Publicaciones agradeciendo el rol del NLHPC en su investigación
2016 |
Escalona, Yerko; Garate, Jose~A.; Araya-Secchi, Raul; Huynh, Tien; Zhou, Ruhong; Perez-Acle, Tomas Exploring the Membrane Potential of Simple Dual-Membrane Systems as Models for Gap-Junction Channels Journal Article Biophysical Journal, 110 (12), pp. 2678–2688, 2016. @article{Escalona2016b, title = {Exploring the Membrane Potential of Simple Dual-Membrane Systems as Models for Gap-Junction Channels}, author = {Yerko Escalona and Jose~A. Garate and Raul Araya-Secchi and Tien Huynh and Ruhong Zhou and Tomas Perez-Acle}, url = {https://doi.org/10.1016/j.bpj.2016.05.005}, doi = {10.1016/j.bpj.2016.05.005}, year = {2016}, date = {2016-06-01}, journal = {Biophysical Journal}, volume = {110}, number = {12}, pages = {2678--2688}, publisher = {Elsevier BV}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
ø, Sigbj; Koop, Ben F; Sandve, Simen R; Miller, Jason R; Kent, Matthew P; Nome, Torfinn; Hvidsten, Torgeir R; Leong, Jong S; Minkley, David R; Zimin, Aleksey; Grammes, Fabian; Grove, Harald; Gjuvsland, Arne; Walenz, Brian; Hermansen, Russell A; von Schalburg, Kris; Rondeau, Eric B; Genova, Alex Di; Samy, Jeevan K A; Vik, Jon Olav; Vigeland, Magnus D; Caler, Lis; Grimholt, Unni; Jentoft, Sissel; Våge, Dag Inge; de Jong, Pieter; Moen, Thomas; Baranski, Matthew; Palti, Yniv; Smith, Douglas R; Yorke, James A; Nederbragt, Alexander J; Tooming-Klunderud, Ave; Jakobsen, Kjetill S; Jiang, Xuanting; Fan, Dingding; Hu, Yan; Liberles, David A; Vidal, Rodrigo; Iturra, Patricia; Jones, Steven J M; Jonassen, Inge; Maass, Alejandro; Omholt, Stig W; Davidson, William S The Atlantic salmon genome provides insights into rediploidization Journal Article Nature, 533 (7602), pp. 200–205, 2016. @article{Lien2016, title = {The Atlantic salmon genome provides insights into rediploidization}, author = {Sigbj \o and Ben F Koop and Simen R Sandve and Jason R Miller and Matthew P Kent and Torfinn Nome and Torgeir R Hvidsten and Jong S Leong and David R Minkley and Aleksey Zimin and Fabian Grammes and Harald Grove and Arne Gjuvsland and Brian Walenz and Russell A Hermansen and Kris von Schalburg and Eric B Rondeau and Alex Di Genova and Jeevan K A Samy and Jon Olav Vik and Magnus D Vigeland and Lis Caler and Unni Grimholt and Sissel Jentoft and Dag Inge Vr{a}ge and Pieter de Jong and Thomas Moen and Matthew Baranski and Yniv Palti and Douglas R Smith and James A Yorke and Alexander J Nederbragt and Ave Tooming-Klunderud and Kjetill S Jakobsen and Xuanting Jiang and Dingding Fan and Yan Hu and David A Liberles and Rodrigo Vidal and Patricia Iturra and Steven J M Jones and Inge Jonassen and Alejandro Maass and Stig W Omholt and William S Davidson}, url = {https://doi.org/10.1038/nature17164}, doi = {10.1038/nature17164}, year = {2016}, date = {2016-04-01}, journal = {Nature}, volume = {533}, number = {7602}, pages = {200--205}, publisher = {Springer Nature}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Utreras, José; Becerra, Fernando; Escala, Andrés Unveiling the Role of Galactic Rotation on Star Formation Journal Article The Astrophysical Journal, 833 (1), pp. 13, 2016. @article{0004-637X-833-1-13, title = {Unveiling the Role of Galactic Rotation on Star Formation}, author = {Jos\'{e} Utreras and Fernando Becerra and Andr\'{e}s Escala}, url = {http://stacks.iop.org/0004-637X/833/i=1/a=13}, year = {2016}, date = {2016-01-01}, journal = {The Astrophysical Journal}, volume = {833}, number = {1}, pages = {13}, abstract = {We study the star formation process at galactic scales and the role of rotation through numerical simulations of spiral and starburst galaxies using the adaptive mesh refinement code Enzo. We focus on the study of three integrated star formation laws found in the literature: the Kennicutt\textendashSchmidt (KS) and Silk\textendashElmegreen (SE) laws, and the dimensionally homogeneous equation proposed by Escala ##IMG## [http://ej.iop.org/images/0004-637X/833/1/13/apjaa4674ieqn1.gif] $rmSigma _mathrmSFRpropto sqrtG/LrmSigma _mathrmgas^1.5$ . We show that using the last we take into account the effects of the integration along the line of sight and find a unique regime of star formation for both types of galaxies, suppressing the observed bi-modality of the KS law. We find that the efficiencies displayed by our simulations are anti-correlated with the angular velocity of the disk Ω for the three laws studied in this work. Finally, we show that the dimensionless efficiency of star formation is well represented by an exponentially decreasing function of ##IMG## [http://ej.iop.org/images/0004-637X/833/1/13/apjaa4674ieqn2.gif] $-1.9rm\Omega {t}_mathrmff^mathrmini$ , where ##IMG## [http://ej.iop.org/images/0004-637X/833/1/13/apjaa4674ieqn3.gif] ${t}_mathrmff^mathrmini$ is the initial free-fall time. This leads to a unique galactic star formation relation which reduces the scatter of the bi-modal KS, SE, and Escala relations by 43%, 43%, and 35%, respectively.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We study the star formation process at galactic scales and the role of rotation through numerical simulations of spiral and starburst galaxies using the adaptive mesh refinement code Enzo. We focus on the study of three integrated star formation laws found in the literature: the Kennicutt–Schmidt (KS) and Silk–Elmegreen (SE) laws, and the dimensionally homogeneous equation proposed by Escala ##IMG## [http://ej.iop.org/images/0004-637X/833/1/13/apjaa4674ieqn1.gif] $rmSigma _mathrmSFRpropto sqrtG/LrmSigma _mathrmgas^1.5$ . We show that using the last we take into account the effects of the integration along the line of sight and find a unique regime of star formation for both types of galaxies, suppressing the observed bi-modality of the KS law. We find that the efficiencies displayed by our simulations are anti-correlated with the angular velocity of the disk Ω for the three laws studied in this work. Finally, we show that the dimensionless efficiency of star formation is well represented by an exponentially decreasing function of ##IMG## [http://ej.iop.org/images/0004-637X/833/1/13/apjaa4674ieqn2.gif] $-1.9rmØmega ŧ_mathrmff^mathrmini$ , where ##IMG## [http://ej.iop.org/images/0004-637X/833/1/13/apjaa4674ieqn3.gif] $ŧ_mathrmff^mathrmini$ is the initial free-fall time. This leads to a unique galactic star formation relation which reduces the scatter of the bi-modal KS, SE, and Escala relations by 43%, 43%, and 35%, respectively. |
Orhan, Ilkay Erdogan ; Kucukboyaci, Nurgun ; Calis, Ihsan ; Cerón-Carrasco, José P; Den-Haan, Helena ; Peña-García, Jorge ; Pérez-Sánchez, Horacio Phytochemistry Letters, 2016, ISSN: 18767486. @article{orhan_acetylcholinesterase_2016, title = {Acetylcholinesterase inhibitory assessment of isolated constituents from Salsola grandis Freitag, Vural & Adig\"{u}zel and molecular modeling studies on N-acetyltryptophan}, author = {Orhan, Ilkay Erdogan and Kucukboyaci, Nurgun and Calis, Ihsan and Cer\'{o}n-Carrasco, Jos\'{e} P. and Den-Haan, Helena and Pe\~{n}a-Garc\'{i}a, Jorge and P\'{e}rez-S\'{a}nchez, Horacio}, url = {http://dx.doi.org/10.1016/j.phytol.2016.10.017}, doi = {10.1016/j.phytol.2016.10.017}, issn = {18767486}, year = {2016}, date = {2016-01-01}, journal = {Phytochemistry Letters}, abstract = {S. grandis Freitag, Vural & N. Adig??zel is an endemic plant species to Turkey. Since some other Salsola species have been reported to exert cholinesterase inhibitory effect, we aimed to investigate its inhibitory potential against AChE. The EtOH extract and thirteen constituents [ten flavonol derivatives; e.g. isorhamnetin-3-O-rutinoside (1), quercetin-3-O-rutinoside (2), quercetin-3-O-metylether (3), tiliroside (4), isorhamnetin-3-glucuronide (5), isorhamnetin-3-O-glucoside (6), quercetin-3-O-galactoside (7), quercetin-3-O-rhamnoside (8), quercetin (9), and manghaslin (10), two oleanane-type saponosides; e.g. momordin II b (11) and IIc (12) as well as one amino acid derivative, N-acetyltryptophan (13)] isolated from the aerial parts of Salsola grandis (Chenopodiaceae) were tested for their possible inhibitory activity against acetylcholinesterase (AChE), related to pathogenesis of Alzheimer's disease. Although the EtOH extract was inactive, among the isolated compounds, only compound 13 exerted a notable inhibition of 64.90 +/- 1.61% at 50??gmL-1, while compound 12 displayed a low inhibition (21.72 +/- 0.99%). Then, compound 13 was further subjected to molecular modeling experiments in order to give insights about its interactions at atomic level with AChE. The data indicated that N-acetyltryptophan (13) could be a promising model molecule for AD treatment.}, keywords = {}, pubstate = {published}, tppubtype = {article} } S. grandis Freitag, Vural & N. Adig??zel is an endemic plant species to Turkey. Since some other Salsola species have been reported to exert cholinesterase inhibitory effect, we aimed to investigate its inhibitory potential against AChE. The EtOH extract and thirteen constituents [ten flavonol derivatives; e.g. isorhamnetin-3-O-rutinoside (1), quercetin-3-O-rutinoside (2), quercetin-3-O-metylether (3), tiliroside (4), isorhamnetin-3-glucuronide (5), isorhamnetin-3-O-glucoside (6), quercetin-3-O-galactoside (7), quercetin-3-O-rhamnoside (8), quercetin (9), and manghaslin (10), two oleanane-type saponosides; e.g. momordin II b (11) and IIc (12) as well as one amino acid derivative, N-acetyltryptophan (13)] isolated from the aerial parts of Salsola grandis (Chenopodiaceae) were tested for their possible inhibitory activity against acetylcholinesterase (AChE), related to pathogenesis of Alzheimer's disease. Although the EtOH extract was inactive, among the isolated compounds, only compound 13 exerted a notable inhibition of 64.90 +/- 1.61% at 50??gmL-1, while compound 12 displayed a low inhibition (21.72 +/- 0.99%). Then, compound 13 was further subjected to molecular modeling experiments in order to give insights about its interactions at atomic level with AChE. The data indicated that N-acetyltryptophan (13) could be a promising model molecule for AD treatment. |
Ding, Mei ; Cutsail III, George E; Aravena, Daniel ; Amoza, Martín ; Rouzières, Mathieu ; Dechambenoit, Pierre ; Losovyj, Yaroslav ; Pink, Maren ; Ruiz, Eliseo ; Clérac, Rodolphe ; Smith, Jeremy M A low spin manganese (IV) nitride single molecule magnet Journal Article Chem. Sci., 7 (9), pp. 6132–6140, 2016, ISSN: 2041-6520. @article{ding_low_2016, title = {A low spin manganese (IV) nitride single molecule magnet}, author = {Ding, Mei and Cutsail III, George E. and Aravena, Daniel and Amoza, Mart\'{i}n and Rouzi\`{e}res, Mathieu and Dechambenoit, Pierre and Losovyj, Yaroslav and Pink, Maren and Ruiz, Eliseo and Cl\'{e}rac, Rodolphe and Smith, Jeremy M.}, url = {http://xlink.rsc.org/?DOI=C6SC01469K}, doi = {10.1039/C6SC01469K}, issn = {2041-6520}, year = {2016}, date = {2016-01-01}, journal = {Chem. Sci.}, volume = {7}, number = {9}, pages = {6132--6140}, abstract = {Structural, spectroscopic and magnetic methods have been used to characterize the tris(carbene)borate compound PhB(MesIm)3Mn≡N as a four-coordinate manganese(IV) complex with a low spin (S = 1/2) configuration. The slow relaxation of the magnetization in this complex, i.e. its single-molecule magnet (SMM) properties, is revealed under an applied dc field. Multireference quantum mechanical calculations indicate that this SMM behavior originates from an anisotropic ground doublet stabilized by spin-orbit coupling. Consistent theoretical and experiment data show that the resulting magnetization dynamics in this system is dominated by ground state quantum tunneling, while its temperature dependence is attributed to Raman relaxation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Structural, spectroscopic and magnetic methods have been used to characterize the tris(carbene)borate compound PhB(MesIm)3Mn≡N as a four-coordinate manganese(IV) complex with a low spin (S = 1/2) configuration. The slow relaxation of the magnetization in this complex, i.e. its single-molecule magnet (SMM) properties, is revealed under an applied dc field. Multireference quantum mechanical calculations indicate that this SMM behavior originates from an anisotropic ground doublet stabilized by spin-orbit coupling. Consistent theoretical and experiment data show that the resulting magnetization dynamics in this system is dominated by ground state quantum tunneling, while its temperature dependence is attributed to Raman relaxation. |
Mediavilla, D G; Figueroa, D Assessment, sources and predictability of the swell wave power arriving to Chile Journal Article Renewable Energy, pp. 1–12, 2016, ISSN: 18790682. @article{mediavilla_assessment_2016, title = {Assessment, sources and predictability of the swell wave power arriving to Chile}, author = {Mediavilla, D. G. and Figueroa, D.}, url = {http://dx.doi.org/10.1016/j.renene.2017.03.014}, doi = {10.1016/j.renene.2017.03.014}, issn = {18790682}, year = {2016}, date = {2016-01-01}, journal = {Renewable Energy}, pages = {1--12}, abstract = {Located at the western border of South America, Chile lacks appreciable reservoirs of fossil fuels, and has begun an effort for developing renewable energies. As the wave power increases to the south, and the southern border of the Chilean Interconnected electrical network lies by 40??S, the zone around Chilo?? Island represents a unique opportunity for harvesting wave energy. Using results from a 20-year global numerical wave model we assessed the wave power and its variability for the Chilean coast, and we determined the sources of the swell arriving to the coast. Wave power and wave arriving direction increased rather steadily from 25 kW/m and SW at the northern Chile (???18??S) to 100 kW/m and W near the south (???54??S). A validated high resolution wave model was developed for the ocean around Chilo?? Island. Determination of wave generation zones allows foreseeing a potentially accurate forecast of wave energy for this area. Total wave power along 10% of the coastline of Chilo?? Island is of around 1800 MW-720 MW during the year. We postulate that wave energy harvesting could fulfill the electricity needs at the remote regions of Southern Chile.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Located at the western border of South America, Chile lacks appreciable reservoirs of fossil fuels, and has begun an effort for developing renewable energies. As the wave power increases to the south, and the southern border of the Chilean Interconnected electrical network lies by 40??S, the zone around Chilo?? Island represents a unique opportunity for harvesting wave energy. Using results from a 20-year global numerical wave model we assessed the wave power and its variability for the Chilean coast, and we determined the sources of the swell arriving to the coast. Wave power and wave arriving direction increased rather steadily from 25 kW/m and SW at the northern Chile (???18??S) to 100 kW/m and W near the south (???54??S). A validated high resolution wave model was developed for the ocean around Chilo?? Island. Determination of wave generation zones allows foreseeing a potentially accurate forecast of wave energy for this area. Total wave power along 10% of the coastline of Chilo?? Island is of around 1800 MW-720 MW during the year. We postulate that wave energy harvesting could fulfill the electricity needs at the remote regions of Southern Chile. |
Vatter, By Benjamin A structural model of hospital and insurer competition PhD Thesis 2016. @phdthesis{vatter_structural_2016, title = {A structural model of hospital and insurer competition}, author = {Vatter, By Benjamin}, year = {2016}, date = {2016-01-01}, abstract = {This paper studies a model of the health insurance market, in which insur- ers act as intermediaries between consumers and health care providers. Health insurers negotiate service prices with providers and later compete by setting pre- miums to a collection of health insurance plans. Building upon recent work by Gowrisankaran et al. (2015) and Ho and Lee (2013), I formulate a framework to study the interactions between upstream and downstream competition in the health care market. The model allows the analysis of both vertical and horizon- tal mergers in the market, while accounting for the downstream competition in premiums. This structural model is estimated using individual level data from the Chilean private health insurance market. The results are used to conduct a counter-factual analysis to study the effects of upstream vertical integration.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } This paper studies a model of the health insurance market, in which insur- ers act as intermediaries between consumers and health care providers. Health insurers negotiate service prices with providers and later compete by setting pre- miums to a collection of health insurance plans. Building upon recent work by Gowrisankaran et al. (2015) and Ho and Lee (2013), I formulate a framework to study the interactions between upstream and downstream competition in the health care market. The model allows the analysis of both vertical and horizon- tal mergers in the market, while accounting for the downstream competition in premiums. This structural model is estimated using individual level data from the Chilean private health insurance market. The results are used to conduct a counter-factual analysis to study the effects of upstream vertical integration. |
Levin, Eugene ; Lipatov, Lev ; Siddikov, Marat BFKL Pomeron with massive gluons and running coupling Journal Article Physical Review D - Particles, Fields, Gravitation and Cosmology, 94 (9), pp. 1–14, 2016, ISSN: 15502368. @article{levin_bfkl_2016, title = {BFKL Pomeron with massive gluons and running coupling}, author = {Levin, Eugene and Lipatov, Lev and Siddikov, Marat}, doi = {10.1103/PhysRevD.94.096004}, issn = {15502368}, year = {2016}, date = {2016-01-01}, journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, volume = {94}, number = {9}, pages = {1--14}, abstract = {? 2016 American Physical Society.The purpose of this paper is to calculate the Pomeron intercepts from the BFKL equation with the running coupling constant and the gluon mass generated by the Higgs-like mechanism, and to estimate the influence of the infrared dynamics on the spectrum. We found that as in the massless case, the spectrum of positive Regge singularities is discrete and the leading Pomeron has a considerable dependence on nonperturbative effects. We cross-checked this result with finite element analysis, semiclassical approximation and variational methods and confirmed the infrared sensitivity of the leading Pomeron. This fact is related to the infrared instability of the BFKL equation in QCD, with a running coupling. The subleading poles have a mild sensitivity to the soft physics, and are well described by known semiclassical methods. Also for the first time we study the BFKL equation for the various running coupling prescriptions suggested in the literature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } ? 2016 American Physical Society.The purpose of this paper is to calculate the Pomeron intercepts from the BFKL equation with the running coupling constant and the gluon mass generated by the Higgs-like mechanism, and to estimate the influence of the infrared dynamics on the spectrum. We found that as in the massless case, the spectrum of positive Regge singularities is discrete and the leading Pomeron has a considerable dependence on nonperturbative effects. We cross-checked this result with finite element analysis, semiclassical approximation and variational methods and confirmed the infrared sensitivity of the leading Pomeron. This fact is related to the infrared instability of the BFKL equation in QCD, with a running coupling. The subleading poles have a mild sensitivity to the soft physics, and are well described by known semiclassical methods. Also for the first time we study the BFKL equation for the various running coupling prescriptions suggested in the literature. |
Orellana, Walter ; Menéndez-Proupin, Eduardo ; Flores, Mauricio A Chlorine impurities near stacking fault in CdTe Technical Report 2016. @techreport{orellana_chlorine_2016, title = {Chlorine impurities near stacking fault in CdTe}, author = {Orellana, Walter and Men\'{e}ndez-Proupin, Eduardo and Flores, Mauricio A}, year = {2016}, date = {2016-01-01}, abstract = {Thin-film cadmium telluride (CdTe) is an important low-cost photovoltaic material. However, transmission electron microscopy has revealed high density of extended defects like stacking faults in as-grown CdTe samples. It has also been observed that the presence of chlorine (Cl) and its interaction with stacking faults plays an important role in the production of high efficiency thin-film CdTe solar cell. Here, we investigate the stability and electronic properties of the Cl impurity at a stacking-fault defect in CdTe, using density functional theory calculations, including hybrid functional. We find that the presence of the stacking fault removes the degeneracy of the valence band maximum, inducing a reduction of the bandgap of about 0.1 eV. When chlorine is incorporated close to the stacking fault, the substitutional ClTe has lower formation energy, showing a p-type characteristic. On the other hand, interstitial chlorine (Cli)showsthree stablesites withsimilar formation energies. Themost stableone islocated at the stackingfault center, exhibitingahalf-occupied midgap level.}, keywords = {}, pubstate = {published}, tppubtype = {techreport} } Thin-film cadmium telluride (CdTe) is an important low-cost photovoltaic material. However, transmission electron microscopy has revealed high density of extended defects like stacking faults in as-grown CdTe samples. It has also been observed that the presence of chlorine (Cl) and its interaction with stacking faults plays an important role in the production of high efficiency thin-film CdTe solar cell. Here, we investigate the stability and electronic properties of the Cl impurity at a stacking-fault defect in CdTe, using density functional theory calculations, including hybrid functional. We find that the presence of the stacking fault removes the degeneracy of the valence band maximum, inducing a reduction of the bandgap of about 0.1 eV. When chlorine is incorporated close to the stacking fault, the substitutional ClTe has lower formation energy, showing a p-type characteristic. On the other hand, interstitial chlorine (Cli)showsthree stablesites withsimilar formation energies. Themost stableone islocated at the stackingfault center, exhibitingahalf-occupied midgap level. |
Garrido, José Matías ; Cartes, Marcela ; Mejía, Andrés Coarse-grained theoretical modeling and molecular simulations of nitrogen + n-alkanes: (n-pentane, n-hexane, n-heptane, n-octane) Journal Article Journal of Supercritical Fluids, pp. 1–8, 2016, ISSN: 08968446. @article{garrido_coarse-grained_2016, title = {Coarse-grained theoretical modeling and molecular simulations of nitrogen + n-alkanes: (n-pentane, n-hexane, n-heptane, n-octane)}, author = {Garrido, Jos\'{e} Mat\'{i}as and Cartes, Marcela and Mej\'{i}a, Andr\'{e}s}, url = {http://dx.doi.org/10.1016/j.supflu.2017.01.001}, doi = {10.1016/j.supflu.2017.01.001}, issn = {08968446}, year = {2016}, date = {2016-01-01}, journal = {Journal of Supercritical Fluids}, pages = {1--8}, abstract = {The variation of the interfacial tension (IFT) with the pressure and molecular chain length as well as the impact of the interfacial adsorption of nitrogen on IFT are described for four binary systems composed by n-alkanes (n-pentane, n-hexane, n-heptane, n-octane) pressurized by nitrogen.Calculations are based on the Square Gradient Theory (SGT) applied to the Statistical Associated Fluid Theory equation of state and Coarse-Grained Molecular Dynamics (MD) simulations. The molecular descriptors of pure fluids (chain length, repulsive/attractive exponents and size/energy scale) and the interfacial parameters involve in SGT are fully obtained by applying the corresponding states principia and scaling arguments. The approach used here only needs the critical temperature, acentric factor and a single data of the saturate liquid density of pure fluids, which implies that it is entirely predictive for mixtures.According to our results, the interfacial tensions of the binary mixtures decrease as the pressure increases. Particularly, the reduction of IFT with increasing pressure at isothermal conditions evidences adsorption of nitrogen at the n-alkane surface, a behavior that was clearly corroborated by analyzing the trend of concentration profiles and Gibbs adsorption isotherms. Results based on SGT and MD revel that as the molecular chain length increases (from n-pentane to n-octane), the surface activity increases and the interface width decreases, implying thus that the IFT of the mixture increases.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The variation of the interfacial tension (IFT) with the pressure and molecular chain length as well as the impact of the interfacial adsorption of nitrogen on IFT are described for four binary systems composed by n-alkanes (n-pentane, n-hexane, n-heptane, n-octane) pressurized by nitrogen.Calculations are based on the Square Gradient Theory (SGT) applied to the Statistical Associated Fluid Theory equation of state and Coarse-Grained Molecular Dynamics (MD) simulations. The molecular descriptors of pure fluids (chain length, repulsive/attractive exponents and size/energy scale) and the interfacial parameters involve in SGT are fully obtained by applying the corresponding states principia and scaling arguments. The approach used here only needs the critical temperature, acentric factor and a single data of the saturate liquid density of pure fluids, which implies that it is entirely predictive for mixtures.According to our results, the interfacial tensions of the binary mixtures decrease as the pressure increases. Particularly, the reduction of IFT with increasing pressure at isothermal conditions evidences adsorption of nitrogen at the n-alkane surface, a behavior that was clearly corroborated by analyzing the trend of concentration profiles and Gibbs adsorption isotherms. Results based on SGT and MD revel that as the molecular chain length increases (from n-pentane to n-octane), the surface activity increases and the interface width decreases, implying thus that the IFT of the mixture increases. |
Martín-Rodríguez, Alejandro ; Aravena, Daniel ; Ruiz, Eliseo DFT approaches to transport calculations in magnetic single-molecule devices Journal Article Theoretical Chemistry Accounts, 135 (8), pp. 1–10, 2016, ISSN: 1432881X. @article{martin-rodriguez_dft_2016, title = {DFT approaches to transport calculations in magnetic single-molecule devices}, author = {Mart\'{i}n-Rodr\'{i}guez, Alejandro and Aravena, Daniel and Ruiz, Eliseo}, doi = {10.1007/s00214-016-1941-6}, issn = {1432881X}, year = {2016}, date = {2016-01-01}, journal = {Theoretical Chemistry Accounts}, volume = {135}, number = {8}, pages = {1--10}, abstract = {Electron transport properties of single-molecule devices based on the [Fe(tzpy)2(NCS)2] complex placed between two gold electrodes have been explored using three different atomistic DFT methods. This kind of single-molecule devices is quite appealing because they can present magnetoresistance effects at room temperature. The three employed computational approaches are: (i) self-consistent non-equilibrium Green functions (NEGF) with periodic models that can be described as the most accurate between the state-of-art methods, and two non-self-consistent NEGF approaches using either periodic or non-periodic description of the electrodes (ii and iii). The analysis of the transmission spectra obtained with the three methods indicates that they provide similar qualitative results. To obtain a reasonable agreement with the experimental data, it is mandatory to employ density functionals beyond the commonly employed GGA (i.e., hybrid functionals) or to include on-site corrections for the Coulomb repulsion (GGA+U method).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Electron transport properties of single-molecule devices based on the [Fe(tzpy)2(NCS)2] complex placed between two gold electrodes have been explored using three different atomistic DFT methods. This kind of single-molecule devices is quite appealing because they can present magnetoresistance effects at room temperature. The three employed computational approaches are: (i) self-consistent non-equilibrium Green functions (NEGF) with periodic models that can be described as the most accurate between the state-of-art methods, and two non-self-consistent NEGF approaches using either periodic or non-periodic description of the electrodes (ii and iii). The analysis of the transmission spectra obtained with the three methods indicates that they provide similar qualitative results. To obtain a reasonable agreement with the experimental data, it is mandatory to employ density functionals beyond the commonly employed GGA (i.e., hybrid functionals) or to include on-site corrections for the Coulomb repulsion (GGA+U method). |
Wladdimiro, Daniel ; Gonzalez-cantergiani, Pablo ; Hidalgo, Nicolas ; Rosas, Erika Disaster Management Platform to Support Real-time Analytics Technical Report Universidad de Santiago 2016. @techreport{wladdimiro_disaster_2016, title = {Disaster Management Platform to Support Real-time Analytics}, author = {Wladdimiro, Daniel and Gonzalez-cantergiani, Pablo and Hidalgo, Nicolas and Rosas, Erika}, year = {2016}, date = {2016-01-01}, pages = {8}, institution = {Universidad de Santiago}, abstract = {Every year, thousands of disasters impact the world, generating substantial loss in terms of lives and public infras- tructure. The recovery phase requires substantial money invest- ment for governments, in order to rebuild the affected region. To minimize the effects of a disaster, applications supporting decision-making through real-time analytics must be fast and accurate. These tools may be supported by stream processing systems that enable the real-time processing of structure-less data; however, their use and configuration require expert pro- gramming knowledge and a setup phase that could lead to loss relevant data. This work proposes a platform based on stream processing systems for supporting the analysis of large streams of data emitted in case the event of disasters. This platform facilitates deploying applications tailored for specific disaster scenarios, provides elasticity in case of changes in the amount of traffic and enables applying migration to increase robustness.We have built a study case to detect needs in case of an earthquake and discuss the properties of the system.}, keywords = {}, pubstate = {published}, tppubtype = {techreport} } Every year, thousands of disasters impact the world, generating substantial loss in terms of lives and public infras- tructure. The recovery phase requires substantial money invest- ment for governments, in order to rebuild the affected region. To minimize the effects of a disaster, applications supporting decision-making through real-time analytics must be fast and accurate. These tools may be supported by stream processing systems that enable the real-time processing of structure-less data; however, their use and configuration require expert pro- gramming knowledge and a setup phase that could lead to loss relevant data. This work proposes a platform based on stream processing systems for supporting the analysis of large streams of data emitted in case the event of disasters. This platform facilitates deploying applications tailored for specific disaster scenarios, provides elasticity in case of changes in the amount of traffic and enables applying migration to increase robustness.We have built a study case to detect needs in case of an earthquake and discuss the properties of the system. |
Ruiz-Fernández, A R; López-Cascales, J J; Giner-Casares, J J; Araya-Maturana, R; Díaz-Baños, F G; Muñoz-Gacitúa, D; Weiss-López, B E Effect of shape and bending modulus on the properties of nematic lyotropic liquid crystals Journal Article RSC Adv., 6 (9), pp. 7455–7464, 2016, ISSN: 2046-2069. @article{ruiz-fernandez_effect_2016, title = {Effect of shape and bending modulus on the properties of nematic lyotropic liquid crystals}, author = {Ruiz-Fern\'{a}ndez, A. R. and L\'{o}pez-Cascales, J. J. and Giner-Casares, J. J. and Araya-Maturana, R. and D\'{i}az-Ba\~{n}os, F. G. and Mu\~{n}oz-Gacit\'{u}a, D. and Weiss-L\'{o}pez, B. E.}, url = {http://xlink.rsc.org/?DOI=C5RA24019K}, doi = {10.1039/C5RA24019K}, issn = {2046-2069}, year = {2016}, date = {2016-01-01}, journal = {RSC Adv.}, volume = {6}, number = {9}, pages = {7455--7464}, abstract = {Synovial liquid is a natural lubricant of articular joints, such as shoulders, knees and hips. Thus, the development of biocompatible lubricants that can be employed in medical prosthesis for artificial implants, and eventually in certain therapies against osteo-arthritis or rheumatoid-arthritis diseases, is of an undoubted importance. Lyotropic liquid crystals have been used in the synthesis of silica and metals containing regularly oriented nanoporous, to obtain oriented carbon nanotube materials, in several pharmaceutical applications, as membrane mimetics and in lubrication applications. In this context, a new nematic lyotropic liquid crystal has been developed based on tetradecyltrimethyl ammonium chloride (TTAC), decanol (DeOH), a natural mixture of lipids (PL) extracted from soybean and sodium chloride (NaCl), all dissolved in water. A 30% w/w increase in TTAC content respect a certain composition of reference produces a more than 24-fold increase in the macroscopic viscosity of the solution. To understand the molecular principles that explain this behavior, several experimental and theoretical studies have been carried out. In this regard, 2H-NMR quadrupole splittings of fully deuterated sodium dodecyl sulphate (SDS-d25) introduced as molecular probe, transmission electron microscopy (TEM), freeze fracture transmission electron microscopy (FF-TEM), cryogenic transmission electron microscopy (Cryo-TEM) and polarized light microscopy (PLM) were obtained. In addition, hydrodynamic studies determined how the enhancement in viscosity requires a change in the shape of the aggregate, from circular to elliptic. Finally, molecular dynamics simulations allowed to estimate how variations in the bending modulus, kb, can explain the observed tendency of the quadrupole splittings, on the basis of a modification in the flexibility of the aggregate.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Synovial liquid is a natural lubricant of articular joints, such as shoulders, knees and hips. Thus, the development of biocompatible lubricants that can be employed in medical prosthesis for artificial implants, and eventually in certain therapies against osteo-arthritis or rheumatoid-arthritis diseases, is of an undoubted importance. Lyotropic liquid crystals have been used in the synthesis of silica and metals containing regularly oriented nanoporous, to obtain oriented carbon nanotube materials, in several pharmaceutical applications, as membrane mimetics and in lubrication applications. In this context, a new nematic lyotropic liquid crystal has been developed based on tetradecyltrimethyl ammonium chloride (TTAC), decanol (DeOH), a natural mixture of lipids (PL) extracted from soybean and sodium chloride (NaCl), all dissolved in water. A 30% w/w increase in TTAC content respect a certain composition of reference produces a more than 24-fold increase in the macroscopic viscosity of the solution. To understand the molecular principles that explain this behavior, several experimental and theoretical studies have been carried out. In this regard, 2H-NMR quadrupole splittings of fully deuterated sodium dodecyl sulphate (SDS-d25) introduced as molecular probe, transmission electron microscopy (TEM), freeze fracture transmission electron microscopy (FF-TEM), cryogenic transmission electron microscopy (Cryo-TEM) and polarized light microscopy (PLM) were obtained. In addition, hydrodynamic studies determined how the enhancement in viscosity requires a change in the shape of the aggregate, from circular to elliptic. Finally, molecular dynamics simulations allowed to estimate how variations in the bending modulus, kb, can explain the observed tendency of the quadrupole splittings, on the basis of a modification in the flexibility of the aggregate. |
Figueroa, Emilio A; Wachter, Javier A Electronic stopping effects in molecular dynamics simulation of Tungsten Inproceedings XX Simposio Chileno de Física, pp. 1, 2016. @inproceedings{figueroa_electronic_2016, title = {Electronic stopping effects in molecular dynamics simulation of Tungsten}, author = {Figueroa, Emilio A. and Wachter, Javier A.}, year = {2016}, date = {2016-01-01}, booktitle = {XX Simposio Chileno de F\'{i}sica}, pages = {1}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Bartels, Jochen ; Levin, Eugene ; Siddikov, Marat Energy spectrum of the electroweak Pomeron Journal Article Physical Review D - Particles, Fields, Gravitation and Cosmology, 94 (5), pp. 1–17, 2016, ISSN: 15502368. @article{bartels_energy_2016, title = {Energy spectrum of the electroweak Pomeron}, author = {Bartels, Jochen and Levin, Eugene and Siddikov, Marat}, doi = {10.1103/PhysRevD.94.053012}, issn = {15502368}, year = {2016}, date = {2016-01-01}, journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, volume = {94}, number = {5}, pages = {1--17}, abstract = {In this paper we study the high energy behaviour of Electroweak Standard Model for a nonzero Weinberg angle $þeta$ W . We evaluate the spectrum of the electroweak pomeron and demonstrate that the leading intercept is given by α e.w. 4 ln 2 and does not depend on the mixing angle $þeta$ W . Due to its very small numerical value, we conclude that the high energy behaviour of electroweak theory cannot be discussed without including the QCD Pomeron which, at sufficiently large energies, will dominate.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper we study the high energy behaviour of Electroweak Standard Model for a nonzero Weinberg angle $þeta$ W . We evaluate the spectrum of the electroweak pomeron and demonstrate that the leading intercept is given by α e.w. 4 ln 2 and does not depend on the mixing angle $þeta$ W . Due to its very small numerical value, we conclude that the high energy behaviour of electroweak theory cannot be discussed without including the QCD Pomeron which, at sufficiently large energies, will dominate. |
Paulpandi, Rajathi Queen ; Ramasamy, Sivaraj ; Paulraj, Mosae Selvakumar ; Díaz Baños, Guillermo F; Villora, G; Cerón-Carrasco, José P; Pérez-Sánchez, Horacio ; Muthu Vijayan Enoch, Israel V Enhanced Zn2+ ion-sensing behavior of a benzothiazole derivative on encapsulation by β-cyclodextrin Journal Article RSC Adv., 6 (19), pp. 15670–15677, 2016, ISSN: 2046-2069. @article{paulpandi_enhanced_2016, title = {Enhanced Zn2+ ion-sensing behavior of a benzothiazole derivative on encapsulation by β-cyclodextrin}, author = {Paulpandi, Rajathi Queen and Ramasamy, Sivaraj and Paulraj, Mosae Selvakumar and D\'{i}az Ba\~{n}os, F. Guillermo and Villora, G. and Cer\'{o}n-Carrasco, Jos\'{e} P. and P\'{e}rez-S\'{a}nchez, Horacio and Muthu Vijayan Enoch, Israel V.}, url = {http://xlink.rsc.org/?DOI=C6RA01202G}, doi = {10.1039/C6RA01202G}, issn = {2046-2069}, year = {2016}, date = {2016-01-01}, journal = {RSC Adv.}, volume = {6}, number = {19}, pages = {15670--15677}, abstract = {We report, in this paper, a benzothiazole derivative which shows selective binding of zinc ions among a pool of metal ions and the enhanced selectivity of the same metal ion by the derivative in its b-cyclodextrin bound form. The Zn 2+ ion binding is studied using UV-visible absorption and fluorescence spectroscopy. The stoichiometry and binding mode of the benzothiazole derivative-b-cyclodextrin complex are determined using 1D and 2D NMR spectroscopic analysis. The cyclodextrin molecule slides over the benzothiazole derivative and resides above the aminomethyl group linking the benzothiazole and dihydroxyphenyl moieties. The site of binding of the Zn 2+ ion with the compound remains the same both in the compound's free and cyclodextrin-complexed forms. Molecular modeling studies were also carried out in order to obtain more details about the cyclodextrin-compound and Zn 2+ -compound interactions, and their results are in close agreement with obtained experimental data.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report, in this paper, a benzothiazole derivative which shows selective binding of zinc ions among a pool of metal ions and the enhanced selectivity of the same metal ion by the derivative in its b-cyclodextrin bound form. The Zn 2+ ion binding is studied using UV-visible absorption and fluorescence spectroscopy. The stoichiometry and binding mode of the benzothiazole derivative-b-cyclodextrin complex are determined using 1D and 2D NMR spectroscopic analysis. The cyclodextrin molecule slides over the benzothiazole derivative and resides above the aminomethyl group linking the benzothiazole and dihydroxyphenyl moieties. The site of binding of the Zn 2+ ion with the compound remains the same both in the compound's free and cyclodextrin-complexed forms. Molecular modeling studies were also carried out in order to obtain more details about the cyclodextrin-compound and Zn 2+ -compound interactions, and their results are in close agreement with obtained experimental data. |
Ríos-González, J A; Menéndez-Proupin, E Estudio teórico de CdTe dopado con bismuto Inproceedings XX Simposio Chileno de Física, pp. 1, 2016. @inproceedings{rios-gonzalez_estudio_2016, title = {Estudio te\'{o}rico de CdTe dopado con bismuto}, author = {R\'{i}os-Gonz\'{a}lez, J A and Men\'{e}ndez-Proupin, E}, year = {2016}, date = {2016-01-01}, booktitle = {XX Simposio Chileno de F\'{i}sica}, pages = {1}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Aravena, Daniel ; Venegas-Yazigi, Diego ; Ruiz, Eliseo Exchange Interactions on the Highest-Spin Reported Molecule: the Mixed-Valence Fe42 Complex Journal Article Scientific Reports, 6 (1), pp. 23847, 2016, ISSN: 2045-2322. @article{aravena_exchange_2016, title = {Exchange Interactions on the Highest-Spin Reported Molecule: the Mixed-Valence Fe42 Complex}, author = {Aravena, Daniel and Venegas-Yazigi, Diego and Ruiz, Eliseo}, url = {http://www.nature.com/articles/srep23847}, doi = {10.1038/srep23847}, issn = {2045-2322}, year = {2016}, date = {2016-01-01}, journal = {Scientific Reports}, volume = {6}, number = {1}, pages = {23847}, abstract = {The finding of high-spin molecules that could behave as conventional magnets has been one of the main challenges in Molecular Magnetism. Here, the exchange interactions, present in the highest-spin molecule published in the literature, Fe 42 , have been analysed using theoretical methods based on Density Functional Theory. The system with a total spin value S = 45 is formed by 42 iron centres containing 18 high-spin Fe III ferromagnetically coupled and 24 diamagnetic low-spin Fe II ions. The bridging ligands between the two paramagnetic centres are two cyanide ligands coordinated to the diamagnetic Fe II cations. Calculations were performed using either small Fe 4 or Fe 3 models or the whole Fe 42 complex, showing the presence of two different ferromagnetic couplings between the paramagnetic Fe III centres. Finally, Quantum Monte Carlo simulations for the whole system were carried out in order to compare the experimental and simulated magnetic susceptibility curves from the calculated exchange coupling constants with the experimental one. This comparison allows for the evaluation of the accuracy of different exchange-correlation functionals to reproduce such magnetic properties. A major goal in the field of Molecular Magnetism is the synthesis of molecules that can play a similar role to conventional magnet (metals or alloys). These molecular systems can provide with new functionalities, such as solubility, photochemical properties and lighter storage units among others 1,2 . The discovery in 1992 of the single-molecule magnet (SMM) behaviour of the Mn 12 molecule, which behaves as a magnet at very low temper-atures, directed the search towards high-spin molecules 3,4 . The energy barrier that fixes the orientation of the spin providing the behaviour as a magnet is equal to textbarDtextbar·S 2 ; being D the the zero-field splitting parameter and S the total spin value 5 . Over the years, the quest to increase the blocking temperature of only 2 K for the Mn 12 (S = 10) 6 has lead towards the syntheses of a large variety of polynuclear complexes with ferromagnetic or ferrimagnetic interactions, aiming to achieve larger values of the total spin 7,8 . Thus, reaching high-spin molecules has been one of the main challenges in this research field. Few years after the discovery of the SMM behaviour, in 1995, a Fe 19 complex was characterized with S = 33/2 being the spin record during the following five years 9,10 . This value was surpassed in 2000 by some heteronuclear Mn 9 M 6 (M = Mo and W) complexes with a total spin of 39/2, respec-tively 11,12 . Initially, a spin of 51/2 was assigned to one of them, the Mn 9 W 6 system, although lately it was corrobo-rated the ferromagnetic nature of the interactions by using theoretical methods with a resulting value of 39/2 for the total spin as well as its analogous with Mo 13 . Few years later, in 2004, the value of S = 51/2 was reached by a Mn 25 complex containing one Mn IV , eighteen Mn III and six Mn II centres 14 . It is worth noting that in such system, the maximum expected S value for a parallel alignment of all the spins would give an S = 105/2. Thus, ferrimag-netic or antiferromagnetic interactions were assumed within the complex. Lately in 2007, the same research group reported another Mn 25 complex with a total spin of 61/2 by replacing the azido ligands of the aforementioned Mn 25 complex by N,O-chelating groups 15}, keywords = {}, pubstate = {published}, tppubtype = {article} } The finding of high-spin molecules that could behave as conventional magnets has been one of the main challenges in Molecular Magnetism. Here, the exchange interactions, present in the highest-spin molecule published in the literature, Fe 42 , have been analysed using theoretical methods based on Density Functional Theory. The system with a total spin value S = 45 is formed by 42 iron centres containing 18 high-spin Fe III ferromagnetically coupled and 24 diamagnetic low-spin Fe II ions. The bridging ligands between the two paramagnetic centres are two cyanide ligands coordinated to the diamagnetic Fe II cations. Calculations were performed using either small Fe 4 or Fe 3 models or the whole Fe 42 complex, showing the presence of two different ferromagnetic couplings between the paramagnetic Fe III centres. Finally, Quantum Monte Carlo simulations for the whole system were carried out in order to compare the experimental and simulated magnetic susceptibility curves from the calculated exchange coupling constants with the experimental one. This comparison allows for the evaluation of the accuracy of different exchange-correlation functionals to reproduce such magnetic properties. A major goal in the field of Molecular Magnetism is the synthesis of molecules that can play a similar role to conventional magnet (metals or alloys). These molecular systems can provide with new functionalities, such as solubility, photochemical properties and lighter storage units among others 1,2 . The discovery in 1992 of the single-molecule magnet (SMM) behaviour of the Mn 12 molecule, which behaves as a magnet at very low temper-atures, directed the search towards high-spin molecules 3,4 . The energy barrier that fixes the orientation of the spin providing the behaviour as a magnet is equal to textbarDtextbar·S 2 ; being D the the zero-field splitting parameter and S the total spin value 5 . Over the years, the quest to increase the blocking temperature of only 2 K for the Mn 12 (S = 10) 6 has lead towards the syntheses of a large variety of polynuclear complexes with ferromagnetic or ferrimagnetic interactions, aiming to achieve larger values of the total spin 7,8 . Thus, reaching high-spin molecules has been one of the main challenges in this research field. Few years after the discovery of the SMM behaviour, in 1995, a Fe 19 complex was characterized with S = 33/2 being the spin record during the following five years 9,10 . This value was surpassed in 2000 by some heteronuclear Mn 9 M 6 (M = Mo and W) complexes with a total spin of 39/2, respec-tively 11,12 . Initially, a spin of 51/2 was assigned to one of them, the Mn 9 W 6 system, although lately it was corrobo-rated the ferromagnetic nature of the interactions by using theoretical methods with a resulting value of 39/2 for the total spin as well as its analogous with Mo 13 . Few years later, in 2004, the value of S = 51/2 was reached by a Mn 25 complex containing one Mn IV , eighteen Mn III and six Mn II centres 14 . It is worth noting that in such system, the maximum expected S value for a parallel alignment of all the spins would give an S = 105/2. Thus, ferrimag-netic or antiferromagnetic interactions were assumed within the complex. Lately in 2007, the same research group reported another Mn 25 complex with a total spin of 61/2 by replacing the azido ligands of the aforementioned Mn 25 complex by N,O-chelating groups 15 |
Cortés-Arriagada, Diego Expanding the environmental applications of metal (Al, Ti, Mn, Fe) doped graphene: adsorption and removal of 1,4-dioxane Journal Article Phys. Chem. Chem. Phys., 18 (47), pp. 32281–32292, 2016, ISSN: 1463-9076. @article{cortes-arriagada_expanding_2016, title = {Expanding the environmental applications of metal (Al, Ti, Mn, Fe) doped graphene: adsorption and removal of 1,4-dioxane}, author = {Cort\'{e}s-Arriagada, Diego}, url = {http://xlink.rsc.org/?DOI=C6CP07311E}, doi = {10.1039/C6CP07311E}, issn = {1463-9076}, year = {2016}, date = {2016-01-01}, journal = {Phys. Chem. Chem. Phys.}, volume = {18}, number = {47}, pages = {32281--32292}, abstract = {The potential applications of Al, Ti, Mn and Fe-doped graphene for environmental remediation of 1,4-dioxane (a critical pollutant and toxic compound) are analyzed in detail in the framework of density functional theory calculations. 1,4-Dioxane is a highly mobile and soluble pollutant and developing new strategies for its adsorption and subsequent removal becomes an important issue. All the systems were fully optimized and analyzed in their most stable spin states. The results determined that the proposed doped-graphene materials enhance the interaction with 1,4-dioxane compared to intrinsic graphene, with adsorption energies in the range of 1.2\textendash1.6 eV. The high stability of the adsorbent\textendashdioxane interactions is fully discussed in terms of chemical metal\textendashdioxane binding, charge transfer and long-range interactions. The adsorbent\textendashdioxane adsorption is also accompanied by changes in the electronic structure with respect to the isolated substrates, which are larger for Mn and Fe as dopants. Ab initio molecular dynamics simulations also show that the adsorbent\textendashadsorbate interactions remain strong at room temperature (300 K). Finally, implicit/explicit solvent methodologies were implemented to get insights into the effects of aqueous environments on the adsorption strength, which shows the high stability of interaction in water, sorting the sorption efficiency as AlG E FeG 4 MnG E TiG. From these new insights, Al, Ti, Mn and Fe-doped graphene emerge as new potential materials to be applied in technologies related to the removal of 1,4-dioxane.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The potential applications of Al, Ti, Mn and Fe-doped graphene for environmental remediation of 1,4-dioxane (a critical pollutant and toxic compound) are analyzed in detail in the framework of density functional theory calculations. 1,4-Dioxane is a highly mobile and soluble pollutant and developing new strategies for its adsorption and subsequent removal becomes an important issue. All the systems were fully optimized and analyzed in their most stable spin states. The results determined that the proposed doped-graphene materials enhance the interaction with 1,4-dioxane compared to intrinsic graphene, with adsorption energies in the range of 1.2–1.6 eV. The high stability of the adsorbent–dioxane interactions is fully discussed in terms of chemical metal–dioxane binding, charge transfer and long-range interactions. The adsorbent–dioxane adsorption is also accompanied by changes in the electronic structure with respect to the isolated substrates, which are larger for Mn and Fe as dopants. Ab initio molecular dynamics simulations also show that the adsorbent–adsorbate interactions remain strong at room temperature (300 K). Finally, implicit/explicit solvent methodologies were implemented to get insights into the effects of aqueous environments on the adsorption strength, which shows the high stability of interaction in water, sorting the sorption efficiency as AlG E FeG 4 MnG E TiG. From these new insights, Al, Ti, Mn and Fe-doped graphene emerge as new potential materials to be applied in technologies related to the removal of 1,4-dioxane. |
Cerón-Carrasco, José P; Den-Haan, Helena ; Peña-García, Jorge ; Contreras-García, Julia ; Pérez-Sánchez, Horacio Exploiting the cyclodextrins ability for antioxidants encapsulation: A computational approach to carnosol and carnosic acid embedding Journal Article Computational and Theoretical Chemistry, 1077 , pp. 65–73, 2016, ISSN: 2210271X. @article{ceron-carrasco_exploiting_2016, title = {Exploiting the cyclodextrins ability for antioxidants encapsulation: A computational approach to carnosol and carnosic acid embedding}, author = {Cer\'{o}n-Carrasco, Jos\'{e} P. and Den-Haan, Helena and Pe\~{n}a-Garc\'{i}a, Jorge and Contreras-Garc\'{i}a, Julia and P\'{e}rez-S\'{a}nchez, Horacio}, doi = {10.1016/j.comptc.2015.10.028}, issn = {2210271X}, year = {2016}, date = {2016-01-01}, journal = {Computational and Theoretical Chemistry}, volume = {1077}, pages = {65--73}, abstract = {Cyclodextrins (CD) are widely used as encapsulation agents for bioactive molecules. Here, we use docking and quantum chemical calculations to ascertain the capability of the three available CDs (α-, β- and γ-CD) to encapsulate carnosol and carnosic acid, which are the most important antioxidants present in the rosemary extract. Docking is revealed as an efficient tool to rank best suited candidates as it quickly discards the molecules that do not fit into CDs cavity. However, more accurate quantum calculations are required to refine the molecular structure as well as to provide reliable interaction energies. According to the reported data, further investigations into the encapsulation of the rosemary extract should be focused on β- and γ-CD rather than in the smaller α-CD, specially if one looks to efficiently preserve their high antioxidant activity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cyclodextrins (CD) are widely used as encapsulation agents for bioactive molecules. Here, we use docking and quantum chemical calculations to ascertain the capability of the three available CDs (α-, β- and γ-CD) to encapsulate carnosol and carnosic acid, which are the most important antioxidants present in the rosemary extract. Docking is revealed as an efficient tool to rank best suited candidates as it quickly discards the molecules that do not fit into CDs cavity. However, more accurate quantum calculations are required to refine the molecular structure as well as to provide reliable interaction energies. According to the reported data, further investigations into the encapsulation of the rosemary extract should be focused on β- and γ-CD rather than in the smaller α-CD, specially if one looks to efficiently preserve their high antioxidant activity. |
Flores, Mauricio A; Orellana, Walter ; Menéndez-Proupin, E First-principles DFT+GW study of O-doped CdTe Journal Article XX Simposio Chileno de Física, pp. 1, 2016. @article{flores_first-principles_2016, title = {First-principles DFT+GW study of O-doped CdTe}, author = {Flores, Mauricio A and Orellana, Walter and Men\'{e}ndez-Proupin, E.}, year = {2016}, date = {2016-01-01}, journal = {XX Simposio Chileno de F\'{i}sica}, pages = {1}, abstract = {Cadmium telluride (CdTe) is one of the few II-VI semiconductors that can be do- ped both n- and p-type. Due to their lar- ge band gap and good mobility, CdTe and its alloys have become of great importan- ce in a wide range of applications including photovoltaics as well as room temperature X-ray and gamma-ray detection. However, harmful deep-energy levels derived from Te antisite (TeCd) are commonly found in as- grown samples. In photovoltaics, CdTe is a promising semiconductors due to its near- optimum band gap of about 1.5 eV, high absorption coefficient, and low manufactu- ring cost [1], which have made it a very im- portant energy material.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cadmium telluride (CdTe) is one of the few II-VI semiconductors that can be do- ped both n- and p-type. Due to their lar- ge band gap and good mobility, CdTe and its alloys have become of great importan- ce in a wide range of applications including photovoltaics as well as room temperature X-ray and gamma-ray detection. However, harmful deep-energy levels derived from Te antisite (TeCd) are commonly found in as- grown samples. In photovoltaics, CdTe is a promising semiconductors due to its near- optimum band gap of about 1.5 eV, high absorption coefficient, and low manufactu- ring cost [1], which have made it a very im- portant energy material. |
Elicer-Cortés, J Gasification of Biomass in an Updraft Fixed Bed Reactor: Effect of Viscous Models Journal Article Journal of Advanced Thermal Science Research, 3 (2), pp. 46–57, 2016, ISSN: 24095826. @article{elicer-cortes_gasification_2016, title = {Gasification of Biomass in an Updraft Fixed Bed Reactor: Effect of Viscous Models}, author = {Elicer-Cort\'{e}s, J.}, url = {http://www.avantipublishers.com/downloads/jatsrv3n2a1/}, doi = {10.15377/2409-5826.2016.03.02.01}, issn = {24095826}, year = {2016}, date = {2016-01-01}, journal = {Journal of Advanced Thermal Science Research}, volume = {3}, number = {2}, pages = {46--57}, abstract = {A numerical study to investigate the influence of viscous models in the biomass gasification in an updraft fixed bed reactor is presented. The unsteady simulations were performed using finite volume method of ANSYS Fluent. A twodimensional axisymmetric transient model was used to simulate the biomass gasification process. The model is based on the Euler-Euler multiphase formulation. The reactive gas-solid flow considers both homogeneous and heterogeneous reactions (drying, pyrolysis, combustion and gasification). Source terms and chemical kinetics are incorporated into the code using user-defined functions programmed in C. Results are validated with experimental data available in the literature for gasification in a continuous reactor. Temperatures and mole fractions of CO, CO2, CH4, Tar, and H2 at the reactor exit are in good agreement with the experimental measurements. Laminar model is agreed with experimental data for net calorific value, however, discrepancies are observed when the k-e mixture model is used. This work provides a methodology for studying gasification in fixed beds using a commercial CFD code which can be used in gasifier design, analysis, and optimization.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A numerical study to investigate the influence of viscous models in the biomass gasification in an updraft fixed bed reactor is presented. The unsteady simulations were performed using finite volume method of ANSYS Fluent. A twodimensional axisymmetric transient model was used to simulate the biomass gasification process. The model is based on the Euler-Euler multiphase formulation. The reactive gas-solid flow considers both homogeneous and heterogeneous reactions (drying, pyrolysis, combustion and gasification). Source terms and chemical kinetics are incorporated into the code using user-defined functions programmed in C. Results are validated with experimental data available in the literature for gasification in a continuous reactor. Temperatures and mole fractions of CO, CO2, CH4, Tar, and H2 at the reactor exit are in good agreement with the experimental measurements. Laminar model is agreed with experimental data for net calorific value, however, discrepancies are observed when the k-e mixture model is used. This work provides a methodology for studying gasification in fixed beds using a commercial CFD code which can be used in gasifier design, analysis, and optimization. |
Aravena, Daniel ; Neese, Frank ; Pantazis, Dimitrios A Improved Segmented All-Electron Relativistically Contracted Basis Sets for the Lanthanides Journal Article Journal of Chemical Theory and Computation, 12 (3), pp. 1148–1156, 2016, ISSN: 15499626. @article{aravena_improved_2016, title = {Improved Segmented All-Electron Relativistically Contracted Basis Sets for the Lanthanides}, author = {Aravena, Daniel and Neese, Frank and Pantazis, Dimitrios A.}, doi = {10.1021/acs.jctc.5b01048}, issn = {15499626}, year = {2016}, date = {2016-01-01}, journal = {Journal of Chemical Theory and Computation}, volume = {12}, number = {3}, pages = {1148--1156}, abstract = {Improved versions of the segmented all-electron relativistically contracted (SARC) basis sets for the lanthanides are presented. The second-generation SARC2 basis sets maintain efficient construction of their predecessors and their individual adaptation to the DKH2 and ZORA Hamiltonians, but feature exponents optimized with a completely new orbital shape fitting procedure and a slightly expanded f space that results in sizable improvement in CASSCF energies and in significantly more accurate prediction of spin\textendashorbit coupling parameters. Additionally, an extended set of polarization/correlation functions is constructed that is appropriate for multireference correlated calculations and new auxiliary basis sets for use in resolution-of-identity (density-fitting) approximations in combination with both DFT and wave function based treatments. Thus, the SARC2 basis sets extend the applicability of the first-generation DFT-oriented basis sets to routine all-electron wave function-based treatments of lanthanide complexes. The new basis sets are benchmarked with respect to excitation energies, radial distribution functions, optimized geometries, orbital eigenvalues, ionization potentials, and spin\textendashorbit coupling parameters of lanthanide systems and are shown to be suitable for the description of magnetic and spectroscopic properties using both DFT and multireference wave function-based methods.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Improved versions of the segmented all-electron relativistically contracted (SARC) basis sets for the lanthanides are presented. The second-generation SARC2 basis sets maintain efficient construction of their predecessors and their individual adaptation to the DKH2 and ZORA Hamiltonians, but feature exponents optimized with a completely new orbital shape fitting procedure and a slightly expanded f space that results in sizable improvement in CASSCF energies and in significantly more accurate prediction of spin–orbit coupling parameters. Additionally, an extended set of polarization/correlation functions is constructed that is appropriate for multireference correlated calculations and new auxiliary basis sets for use in resolution-of-identity (density-fitting) approximations in combination with both DFT and wave function based treatments. Thus, the SARC2 basis sets extend the applicability of the first-generation DFT-oriented basis sets to routine all-electron wave function-based treatments of lanthanide complexes. The new basis sets are benchmarked with respect to excitation energies, radial distribution functions, optimized geometries, orbital eigenvalues, ionization potentials, and spin–orbit coupling parameters of lanthanide systems and are shown to be suitable for the description of magnetic and spectroscopic properties using both DFT and multireference wave function-based methods. |
Muñoz-Becerra, Karina ; Aravena, Daniel ; Ruiz, Eliseo ; Spodine, Evgenia ; Soto-Donoso, Nicolas ; Paredes-Garcia, Veronica ; Venegas-Yazigi, Diego Models to Predict the Magnetic Properties of Single- and Multiple-Bridged Phosphate Cu II Systems: A Theoretical DFT Insight Journal Article Inorg. Chem. Front., 2016, ISSN: 2052-1553. @article{munoz-becerra_models_2016, title = {Models to Predict the Magnetic Properties of Single- and Multiple-Bridged Phosphate Cu II Systems: A Theoretical DFT Insight}, author = {Mu\~{n}oz-Becerra, Karina and Aravena, Daniel and Ruiz, Eliseo and Spodine, Evgenia and Soto-Donoso, Nicolas and Paredes-Garcia, Veronica and Venegas-Yazigi, Diego}, url = {http://pubs.rsc.org/en/Content/ArticleLanding/2016/QI/C6QI00394J}, doi = {10.1039/C6QI00394J}, issn = {2052-1553}, year = {2016}, date = {2016-01-01}, journal = {Inorg. Chem. Front.}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Deneken Guevara, Katherine Optimización del proceso de simulación para un test de bondad de ajuste usando las técnicas computacionales de paralelización disponibles en el lenguaje de programación R PhD Thesis Universidad del Bío-Bío, 2016. @phdthesis{deneken_guevara_optimizacion_2016, title = {Optimizaci\'{o}n del proceso de simulaci\'{o}n para un test de bondad de ajuste usando las t\'{e}cnicas computacionales de paralelizaci\'{o}n disponibles en el lenguaje de programaci\'{o}n R}, author = {Deneken Guevara, Katherine}, year = {2016}, date = {2016-01-01}, school = {Universidad del B\'{i}o-B\'{i}o}, abstract = {Los datos de conteo bivariados surgen en varias disciplinas diferentes y la Distribuci\'{o}n Poisson Bivariada (DPB), siendo una generalizaci\'{o}n de la Distribuci\'{o}n de Poisson (DP), juega un rol importante al momento de modelarlos, siempre que dichos datos presenten una correlaci\'{o}n no negativa. Un aspecto crucial de cualquier an\'{a}lisis de datos es contrastar la bondad de ajuste del modelo supuesto. Novoa-Mu\~{n}oz & Jim\'{e}nez-Gamero, 2014 propusieron tests de bondad de ajuste consistente para la DPB que para aproximar la distribuci\'{o}n nula de los estad\'{i}sticos involucrados emplea el m\'{e}todo bootstrap param\'{e}trico el cual requiere mucho tiempo de simulaci\'{o}n. En este trabajo se experimenta el uso de t\'{e}cnicas de programaci\'{o}n en paralelo mediante el lenguaje de programaci\'{o}n R aplicados a la simulaci\'{o}n del error tipo I del test Rn,w ˆ($þeta$n) propuesto por los autores ya mencionados, utilizando el cl\'{u}ster Leftraru de NLHPC.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Los datos de conteo bivariados surgen en varias disciplinas diferentes y la Distribución Poisson Bivariada (DPB), siendo una generalización de la Distribución de Poisson (DP), juega un rol importante al momento de modelarlos, siempre que dichos datos presenten una correlación no negativa. Un aspecto crucial de cualquier análisis de datos es contrastar la bondad de ajuste del modelo supuesto. Novoa-Muñoz & Jiménez-Gamero, 2014 propusieron tests de bondad de ajuste consistente para la DPB que para aproximar la distribución nula de los estadísticos involucrados emplea el método bootstrap paramétrico el cual requiere mucho tiempo de simulación. En este trabajo se experimenta el uso de técnicas de programación en paralelo mediante el lenguaje de programación R aplicados a la simulación del error tipo I del test Rn,w ˆ($þeta$n) propuesto por los autores ya mencionados, utilizando el clúster Leftraru de NLHPC. |
Collado L, Felipe ; Gyssels, Paolo ; Rodríguez B., Alonso ; Mestres, Marc PORT 21: SISTEMA DE PREVISIÓN DE OCEANOGRAFÍA OPERACIONAL PARA ZONAS COSTERAS Inproceedings XXVII CONGRESO LATINOAMERICANO DE HIDRÁULICA LIMA, PERÚ, 28 AL 30 DE SETIEMBRE DE 2016, Lima, 2016. @inproceedings{collado_l_port_2016, title = {PORT 21: SISTEMA DE PREVISI\'{O}N DE OCEANOGRAF\'{I}A OPERACIONAL PARA ZONAS COSTERAS}, author = {Collado L, Felipe and Gyssels, Paolo and Rodr\'{i}guez B., Alonso and Mestres, Marc}, year = {2016}, date = {2016-01-01}, booktitle = {XXVII CONGRESO LATINOAMERICANO DE HIDR\'{A}ULICA LIMA, PER\'{U}, 28 AL 30 DE SETIEMBRE DE 2016}, address = {Lima}, abstract = {The aim of this paper is the presentation of the System PORT 21 for wave forecasting and Operational Oceanography (OO). For a comprehensive understanding of the system first the methodology adopted for the implementation of PORT 21 is shown and subsequently the study case used to validate and calibrate the system. Finally, the results so far obtained are summarized. A review of the input data System, the different models and wind /wave data sources existing in the state of the art are described, some of which have been selected for routinesystem use. In the conclusions about the results obtained, a critical analysis on the objectives achieved so far is presented and the tasks to be performed in the future are reviewed.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The aim of this paper is the presentation of the System PORT 21 for wave forecasting and Operational Oceanography (OO). For a comprehensive understanding of the system first the methodology adopted for the implementation of PORT 21 is shown and subsequently the study case used to validate and calibrate the system. Finally, the results so far obtained are summarized. A review of the input data System, the different models and wind /wave data sources existing in the state of the art are described, some of which have been selected for routinesystem use. In the conclusions about the results obtained, a critical analysis on the objectives achieved so far is presented and the tasks to be performed in the future are reviewed. |
a Rodriguez, Pedro ; Rivara, Maria-cecilia Relaxed Lepp-Delaunay algorithms for the refinement / improvement of triangulations Journal Article SciVerse ScienceDirect, 00 , pp. 5–9, 2016. @article{rodriguez_relaxed_2016, title = {Relaxed Lepp-Delaunay algorithms for the refinement / improvement of triangulations}, author = {Rodriguez, Pedro a and Rivara, Maria-cecilia}, year = {2016}, date = {2016-01-01}, journal = {SciVerse ScienceDirect}, volume = {00}, pages = {5--9}, abstract = {Longest-edge refinement algorithms for triangulations, based on bisecting the triangles by the longest-edge, were designed to support the development of adaptive finite element software and to guarantee the construction of refined triangulations that maintain the quality of the input mesh [1]. Later the longest-edge propagating path (Lepp) con- cept was introduced by Rivara [2] to design both the Lepp-bisection algorithm (an efficient and simple longest-edge algorithm) and Lepp Delaunay algorithms for the automatic construction of quality triangulations. Lepp-Delaunay algorithms combine the Lepp concept and Delaunay insertion of the selected points. Lepp-centroid algorithm has been studied by Rivara and Calderon [5] and Lepp midpoint algorithms has been studied by Bedregal and Rivara [3]. A study on multicore Lepp-bisection algorithm was presented in [6]. In this paper we propose a Relaxed Lepp-Delaunay method to refine and improve triangulations, where the delau- nization step is relaxed by using a parameter K that constrain the edge flipping propagation around the terminal edge. We present empirical results on a multicore relaxed Lepp-Delaunay algorithm for solving the quality triangulation problem. This method generalizes the Lepp-Centroid Delaunay method discussed in [5].}, keywords = {}, pubstate = {published}, tppubtype = {article} } Longest-edge refinement algorithms for triangulations, based on bisecting the triangles by the longest-edge, were designed to support the development of adaptive finite element software and to guarantee the construction of refined triangulations that maintain the quality of the input mesh [1]. Later the longest-edge propagating path (Lepp) con- cept was introduced by Rivara [2] to design both the Lepp-bisection algorithm (an efficient and simple longest-edge algorithm) and Lepp Delaunay algorithms for the automatic construction of quality triangulations. Lepp-Delaunay algorithms combine the Lepp concept and Delaunay insertion of the selected points. Lepp-centroid algorithm has been studied by Rivara and Calderon [5] and Lepp midpoint algorithms has been studied by Bedregal and Rivara [3]. A study on multicore Lepp-bisection algorithm was presented in [6]. In this paper we propose a Relaxed Lepp-Delaunay method to refine and improve triangulations, where the delau- nization step is relaxed by using a parameter K that constrain the edge flipping propagation around the terminal edge. We present empirical results on a multicore relaxed Lepp-Delaunay algorithm for solving the quality triangulation problem. This method generalizes the Lepp-Centroid Delaunay method discussed in [5]. |
Aravena, Daniel ; Venegas-Yazigi, Diego ; Ruiz, Eliseo Single-Molecule Magnet Properties of Transition-Metal Ions Encapsulated in Lacunary Polyoxometalates: A Theoretical Study Journal Article Inorganic Chemistry, 55 (13), pp. 6405–6413, 2016, ISSN: 1520510X. @article{aravena_single-molecule_2016, title = {Single-Molecule Magnet Properties of Transition-Metal Ions Encapsulated in Lacunary Polyoxometalates: A Theoretical Study}, author = {Aravena, Daniel and Venegas-Yazigi, Diego and Ruiz, Eliseo}, doi = {10.1021/acs.inorgchem.6b00145}, issn = {1520510X}, year = {2016}, date = {2016-01-01}, journal = {Inorganic Chemistry}, volume = {55}, number = {13}, pages = {6405--6413}, abstract = {Single-molecule magnet (SMM) properties of transition-metal complexes coordinated to lacunary polyox-ometalates (POM) are studied by means of state of the art ab initio methodology. Three [M(γ-SiW 10 O 36) 2 ] (M = Mn III , Fe III , Co II) complexes synthesized by Sato et al. (Chem. Commun. 2015, 51, 4081−4084) are analyzed in detail. SMM properties for the Co II and Mn III systems can be rationalized due to the presence of low-energy excitations in the case of Co II , which are much higher in energy in the case of Mn III . The magnetic behavior of both cases is consistent with simple d-orbital splitting considerations. The case of the Fe III complex is special, as it presents a sizable demagnetization barrier for a high-spin d 5 configuration, which should be magnetically isotropic. We conclude that a plausible explanation for this behavior is related to the presence of low-lying quartet and doublet states from the iron(III) center. This scenario is supported by ab initio ligand field analysis based on complete active space self-consistent field results, which picture a d-orbital splitting that resembles more a square-planar geometry than an octahedral one, stabilizing lower multiplicity states. This coordination environment is sustained by the rigidity of the POM ligand, which imposes a longer axial bond distance to the inner oxygen atom in comparison to the more external, equatorial donor atoms.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Single-molecule magnet (SMM) properties of transition-metal complexes coordinated to lacunary polyox-ometalates (POM) are studied by means of state of the art ab initio methodology. Three [M(γ-SiW 10 O 36) 2 ] (M = Mn III , Fe III , Co II) complexes synthesized by Sato et al. (Chem. Commun. 2015, 51, 4081−4084) are analyzed in detail. SMM properties for the Co II and Mn III systems can be rationalized due to the presence of low-energy excitations in the case of Co II , which are much higher in energy in the case of Mn III . The magnetic behavior of both cases is consistent with simple d-orbital splitting considerations. The case of the Fe III complex is special, as it presents a sizable demagnetization barrier for a high-spin d 5 configuration, which should be magnetically isotropic. We conclude that a plausible explanation for this behavior is related to the presence of low-lying quartet and doublet states from the iron(III) center. This scenario is supported by ab initio ligand field analysis based on complete active space self-consistent field results, which picture a d-orbital splitting that resembles more a square-planar geometry than an octahedral one, stabilizing lower multiplicity states. This coordination environment is sustained by the rigidity of the POM ligand, which imposes a longer axial bond distance to the inner oxygen atom in comparison to the more external, equatorial donor atoms. |
Pais, Cristobal ; Weintraub, Andres Stochastic Forestry Planning Problem using Progressive Hedging Technical Report 2016. @techreport{pais_stochastic_2016, title = {Stochastic Forestry Planning Problem using Progressive Hedging}, author = {Pais, Cristobal and Weintraub, Andres}, year = {2016}, date = {2016-01-01}, pages = {52}, abstract = {The forest planning problem with road construction consists of managing the timber production of a land divided into harvest cells. The goal is the maximization of the expected net present value for a tactical plan of a set of 17 forests in Chile, subject to internal (harvesting units' performance) and external (product prices and demand) uncertainties, represented by scenarios associated to probabilities. This enables the planner to make decisions based on a range of possible states for each uncertainty. A methodology for generating scenario trees using a robust mathematical model is applied, with a stochastic process to represent the price movements, obtaining scenarios and their probabilities. It is necessary to include non-anticipativity constraints in the model that link scenarios. This formulation is called the extended formulation (EF). This problem is difficult to solve when the number of scenarios is large, leading to decomposition approaches. A leading algorithm is Progressive Hedging (PH), which decomposes the problem by scenarios. We have implemented this algorithm, with multiple adjustments to improve its solvability. We have compared its performance with the EF. Instances up to 1000 scenarios were successfully solved using parallel programming. Results conclude that the use of PH algorithm, using settings and adjustments made, provides higher performances than traditional optimization techniques for large-scale stochastic problems, with the possibility of exploiting its parallel implementation in similar problems.}, keywords = {}, pubstate = {published}, tppubtype = {techreport} } The forest planning problem with road construction consists of managing the timber production of a land divided into harvest cells. The goal is the maximization of the expected net present value for a tactical plan of a set of 17 forests in Chile, subject to internal (harvesting units' performance) and external (product prices and demand) uncertainties, represented by scenarios associated to probabilities. This enables the planner to make decisions based on a range of possible states for each uncertainty. A methodology for generating scenario trees using a robust mathematical model is applied, with a stochastic process to represent the price movements, obtaining scenarios and their probabilities. It is necessary to include non-anticipativity constraints in the model that link scenarios. This formulation is called the extended formulation (EF). This problem is difficult to solve when the number of scenarios is large, leading to decomposition approaches. A leading algorithm is Progressive Hedging (PH), which decomposes the problem by scenarios. We have implemented this algorithm, with multiple adjustments to improve its solvability. We have compared its performance with the EF. Instances up to 1000 scenarios were successfully solved using parallel programming. Results conclude that the use of PH algorithm, using settings and adjustments made, provides higher performances than traditional optimization techniques for large-scale stochastic problems, with the possibility of exploiting its parallel implementation in similar problems. |
Perinet, Nicolas ; Gutiérrez, Pablo ; Urra, Héctor ; Mujica, Nicolás ; Gordillo, Leonardo Streaming patterns in Faraday waves Journal Article arXiv, pp. 285–310, 2016, ISSN: 14697645. @article{perinet_streaming_2016, title = {Streaming patterns in Faraday waves}, author = {Perinet, Nicolas and Guti\'{e}rrez, Pablo and Urra, H\'{e}ctor and Mujica, Nicol\'{a}s and Gordillo, Leonardo}, doi = {10.1017/jfm.2017.166}, issn = {14697645}, year = {2016}, date = {2016-01-01}, journal = {arXiv}, pages = {285--310}, abstract = {Waves patterns in the Faraday instability have been studied for decades. Besides the rich dynamics that can be observed on the waves at the interface, Faraday waves hide beneath them an elusive range of flow patterns \textemdashor streaming patterns\textemdash which have not been studied in detail until now. The streaming patterns are responsible for a net circulation in the flow which are reminiscent of convection cells. In this article, we analyse these streaming flows by conducting experiments in a Faraday-wave setup. To visualize the flows, tracers are used to generate both trajectory maps and to probe the streaming velocity field via Particle Image Velocimetry (PIV). We identify three types of patterns and experimentally show that identical Faraday waves can mask streaming patterns that are qualitatively very different. Next we propose a three-dimensional model that explains streaming flows in quasi-inviscid fluids. We show that the streaming inside the fluid arises from a complex coupling between the bulk and the boundary layers. This coupling can be taken into account by applying modified boundary conditions in a three-dimensional Navier-Stokes formulation for the streaming in the bulk. Numerical simulations based on this theoretical framework show good qualitative and quantitative agreement with experimental results. They also highlight the relevance of three-dimensional effects in the streaming patterns. Our simulations reveal that the variety of experimental patterns is deeply linked to the boundary condition at the top interface, which may be strongly affected by the presence of contaminants along the surface.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Waves patterns in the Faraday instability have been studied for decades. Besides the rich dynamics that can be observed on the waves at the interface, Faraday waves hide beneath them an elusive range of flow patterns —or streaming patterns— which have not been studied in detail until now. The streaming patterns are responsible for a net circulation in the flow which are reminiscent of convection cells. In this article, we analyse these streaming flows by conducting experiments in a Faraday-wave setup. To visualize the flows, tracers are used to generate both trajectory maps and to probe the streaming velocity field via Particle Image Velocimetry (PIV). We identify three types of patterns and experimentally show that identical Faraday waves can mask streaming patterns that are qualitatively very different. Next we propose a three-dimensional model that explains streaming flows in quasi-inviscid fluids. We show that the streaming inside the fluid arises from a complex coupling between the bulk and the boundary layers. This coupling can be taken into account by applying modified boundary conditions in a three-dimensional Navier-Stokes formulation for the streaming in the bulk. Numerical simulations based on this theoretical framework show good qualitative and quantitative agreement with experimental results. They also highlight the relevance of three-dimensional effects in the streaming patterns. Our simulations reveal that the variety of experimental patterns is deeply linked to the boundary condition at the top interface, which may be strongly affected by the presence of contaminants along the surface. |
Cabrera-vives, Guillermo ; Reyes, Ignacio ; Francisco, F; Est, Pablo A Supernovae Detection by Using Convolutional Neural Networks Journal Article pp. 251–258, 2016. @article{cabrera-vives_supernovae_2016, title = {Supernovae Detection by Using Convolutional Neural Networks}, author = {Cabrera-vives, Guillermo and Reyes, Ignacio and Francisco, F and Est, Pablo A}, year = {2016}, date = {2016-01-01}, pages = {251--258}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Lagos, Carlos F; Campos, Francisca ; Alvarez, Javiera A; Muñoz, Rodrigo ; Varas, Macarena ; Ortíz-Severín, Javiera ; Cabrera, Ricardo ; Chávez, Francisco P Targeting polyphosphate kinase 1 (PPK1) in Pseudomonas aeruginosa PAO1: towards novel antivirulence compounds Technical Report 2016. @techreport{lagos_targeting_2016, title = {Targeting polyphosphate kinase 1 (PPK1) in Pseudomonas aeruginosa PAO1: towards novel antivirulence compounds}, author = {Lagos, Carlos F and Campos, Francisca and Alvarez, Javiera A and Mu\~{n}oz, Rodrigo and Varas, Macarena and Ort\'{i}z-Sever\'{i}n, Javiera and Cabrera, Ricardo and Ch\'{a}vez, Francisco P}, year = {2016}, date = {2016-01-01}, pages = {1}, abstract = {The interest of the pharmaceutical industry in developing novel antimicrobials is decreasing, as established screening systems that identify compounds that kill or inhibit growth of bacteria can no longer be used. In bacteria, inorganic polyphosphate metabolism is not essential for growth but polyP deficiency affects various cellular processes such as bacterial virulence and susceptibility toward antibiotics, including persistence. Consequently, Polyphosphate Kinase 1 (PPK1), the enzyme responsible for polyP synthesis in many bacterial pathogens, has been proposed as a potential drug target for novel antivirulence molecules. Herein, we report the discovery of antivirulence molecules targeting inorganic polyP synthesis in P. aeruginosa PAO1. PPK1Pa was produced in E. coli strain BL21-AI and purified by affinity chromatography. Enzyme kinetics was established using a DAPI-based fluorescence enzyme assay that allows the biological evaluation of drug-like compounds previously selected from virtual screening of the OpenNCI database. Hits were further assayed using D. discoideum as a host-pathogen model. Our screening approach allows the identification of 3 lead compounds that do not kill the bacterial pathogen, avoid affecting the host and its beneficial bacteria and disrupt the production of virulence factors that damage the host.}, keywords = {}, pubstate = {published}, tppubtype = {techreport} } The interest of the pharmaceutical industry in developing novel antimicrobials is decreasing, as established screening systems that identify compounds that kill or inhibit growth of bacteria can no longer be used. In bacteria, inorganic polyphosphate metabolism is not essential for growth but polyP deficiency affects various cellular processes such as bacterial virulence and susceptibility toward antibiotics, including persistence. Consequently, Polyphosphate Kinase 1 (PPK1), the enzyme responsible for polyP synthesis in many bacterial pathogens, has been proposed as a potential drug target for novel antivirulence molecules. Herein, we report the discovery of antivirulence molecules targeting inorganic polyP synthesis in P. aeruginosa PAO1. PPK1Pa was produced in E. coli strain BL21-AI and purified by affinity chromatography. Enzyme kinetics was established using a DAPI-based fluorescence enzyme assay that allows the biological evaluation of drug-like compounds previously selected from virtual screening of the OpenNCI database. Hits were further assayed using D. discoideum as a host-pathogen model. Our screening approach allows the identification of 3 lead compounds that do not kill the bacterial pathogen, avoid affecting the host and its beneficial bacteria and disrupt the production of virulence factors that damage the host. |
Stalevski, Marko ; Ricci, Claudio ; Ueda, Yoshihiro ; Lira, Paulina ; Fritz, Jacopo ; Baes, Maarten The dust covering factor in active galactic nuclei Journal Article Monthly Notices of the Royal Astronomical Society, 458 (3), pp. 2288–2302, 2016, ISSN: 13652966. @article{stalevski_dust_2016, title = {The dust covering factor in active galactic nuclei}, author = {Stalevski, Marko and Ricci, Claudio and Ueda, Yoshihiro and Lira, Paulina and Fritz, Jacopo and Baes, Maarten}, doi = {10.1093/mnras/stw444}, issn = {13652966}, year = {2016}, date = {2016-01-01}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {458}, number = {3}, pages = {2288--2302}, abstract = {The primary source of emission of active galactic nuclei (AGNs), the accretion disc, is sur-rounded by an optically and geometrically thick dusty structure ('the so-called dusty torus'). The infrared radiation emitted by the dust is nothing but a reprocessed fraction of the accretion disc emission, so the ratio of the torus to the AGN luminosity (L torus /L AGN) should corre-sponds to the fraction of the sky obscured by dust, i.e. the covering factor. We undertook a critical investigation of the L torus /L AGN as the dust covering factor proxy. Using state-of-the-art 3D Monte Carlo radiative transfer code, we calculated a grid of spectral energy distributions (SEDs) emitted by the clumpy two-phase dusty structure. With this grid of SEDs, we studied the relation between L torus /L AGN and the dust covering factor for different parameters of the torus. We found that in the case of type 1 AGNs the torus anisotropy makes L torus /L AGN underestimate low covering factors and overestimate high covering factors. In type 2 AGNs L torus /L AGN always underestimates covering factors. Our results provide a novel easy-to-use method to account for anisotropy and obtain correct covering factors. Using two samples from the literature, we demonstrated the importance of our result for inferring the obscured AGN fraction. We found that after the anisotropy is properly accounted for, the dust covering factors show very weak dependence on L AGN , with values in the range of ≈0.6\textendash0.7. Our results also suggest a higher fraction of obscured AGNs at high luminosities than those found by X-ray surveys, in part owing to the presence of a Compton-thick AGN population predicted by population synthesis models.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The primary source of emission of active galactic nuclei (AGNs), the accretion disc, is sur-rounded by an optically and geometrically thick dusty structure ('the so-called dusty torus'). The infrared radiation emitted by the dust is nothing but a reprocessed fraction of the accretion disc emission, so the ratio of the torus to the AGN luminosity (L torus /L AGN) should corre-sponds to the fraction of the sky obscured by dust, i.e. the covering factor. We undertook a critical investigation of the L torus /L AGN as the dust covering factor proxy. Using state-of-the-art 3D Monte Carlo radiative transfer code, we calculated a grid of spectral energy distributions (SEDs) emitted by the clumpy two-phase dusty structure. With this grid of SEDs, we studied the relation between L torus /L AGN and the dust covering factor for different parameters of the torus. We found that in the case of type 1 AGNs the torus anisotropy makes L torus /L AGN underestimate low covering factors and overestimate high covering factors. In type 2 AGNs L torus /L AGN always underestimates covering factors. Our results provide a novel easy-to-use method to account for anisotropy and obtain correct covering factors. Using two samples from the literature, we demonstrated the importance of our result for inferring the obscured AGN fraction. We found that after the anisotropy is properly accounted for, the dust covering factors show very weak dependence on L AGN , with values in the range of ≈0.6–0.7. Our results also suggest a higher fraction of obscured AGNs at high luminosities than those found by X-ray surveys, in part owing to the presence of a Compton-thick AGN population predicted by population synthesis models. |
Förster, Francisco ; Maureira, Juan C; Martín, Jaime San ; Hamuy, Mario ; Martínez, Jorge ; Huijse, Pablo ; Cabrera, Guillermo ; Galbany, Lluís ; de Jaeger, Thomas ; González-Gaitán, Santiago ; Anderson, Joseph P; Kuncarayakti, Hanindyo ; Pignata, Giuliano ; Bufano, Filomena ; Littín, Jorge ; Olivares, Felipe ; Medina, Gustavo ; Smith, Chris R; Vivas, Katherina A; Estévez, Pablo A; Muñoz, Ricardo ; Vera, Eduardo The High Cadence Transient Survey (HiTS) - I. Survey design and supernova shock breakout constraints Journal Article 2016. @article{forster_high_2016, title = {The High Cadence Transient Survey (HiTS) - I. Survey design and supernova shock breakout constraints}, author = {F\"{o}rster, Francisco and Maureira, Juan C. and Mart\'{i}n, Jaime San and Hamuy, Mario and Mart\'{i}nez, Jorge and Huijse, Pablo and Cabrera, Guillermo and Galbany, Llu\'{i}s and de Jaeger, Thomas and Gonz\'{a}lez-Gait\'{a}n, Santiago and Anderson, Joseph P. and Kuncarayakti, Hanindyo and Pignata, Giuliano and Bufano, Filomena and Litt\'{i}n, Jorge and Olivares, Felipe and Medina, Gustavo and Smith, R. Chris and Vivas, A. Katherina and Est\'{e}vez, Pablo A. and Mu\~{n}oz, Ricardo and Vera, Eduardo}, url = {http://arxiv.org/abs/1609.03567%0Ahttp://dx.doi.org/10.3847/0004-637X/832/2/155}, doi = {10.3847/0004-637X/832/2/155}, year = {2016}, date = {2016-01-01}, abstract = {We present the first results of the High cadence Transient Survey (HiTS), a survey whose objective is to detect and follow up optical transients with characteristic timescales from hours to days, especially the earliest hours of supernova (SN) explosions. HiTS uses the Dark Energy Camera (DECam) and a custom made pipeline for image subtraction, candidate filtering and candidate visualization, which runs in real-time to be able to react rapidly to the new transients. We discuss the survey design, the technical challenges associated with the real-time analysis of these large volumes of data and our first results. In our 2013, 2014 and 2015 campaigns we have detected more than 120 young SN candidates, but we did not find a clear signature from the short-lived SN shock breakouts (SBOs) originating after the core collapse of red supergiant stars, which was the initial science aim of this survey. Using the empirical distribution of limiting-magnitudes from our observational campaigns we measured the expected recovery fraction of randomly injected SN light curves which included SBO optical peaks produced with models from Tominaga et al. (2011) and Nakar & Sari (2010). From this analysis we cannot rule out the models from Tominaga et al. (2011) under any reasonable distributions of progenitor masses, but we can marginally rule out the brighter and longer-lived SBO models from Nakar & Sari (2010) under our best-guess distribution of progenitor masses. Finally, we highlight the implications of this work for future massive datasets produced by astronomical observatories such as LSST.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present the first results of the High cadence Transient Survey (HiTS), a survey whose objective is to detect and follow up optical transients with characteristic timescales from hours to days, especially the earliest hours of supernova (SN) explosions. HiTS uses the Dark Energy Camera (DECam) and a custom made pipeline for image subtraction, candidate filtering and candidate visualization, which runs in real-time to be able to react rapidly to the new transients. We discuss the survey design, the technical challenges associated with the real-time analysis of these large volumes of data and our first results. In our 2013, 2014 and 2015 campaigns we have detected more than 120 young SN candidates, but we did not find a clear signature from the short-lived SN shock breakouts (SBOs) originating after the core collapse of red supergiant stars, which was the initial science aim of this survey. Using the empirical distribution of limiting-magnitudes from our observational campaigns we measured the expected recovery fraction of randomly injected SN light curves which included SBO optical peaks produced with models from Tominaga et al. (2011) and Nakar & Sari (2010). From this analysis we cannot rule out the models from Tominaga et al. (2011) under any reasonable distributions of progenitor masses, but we can marginally rule out the brighter and longer-lived SBO models from Nakar & Sari (2010) under our best-guess distribution of progenitor masses. Finally, we highlight the implications of this work for future massive datasets produced by astronomical observatories such as LSST. |
Bachmatiuk, Joanna ; Garcia-gonzalo, Jordi ; Barreiro, Susana ; Pais, Cristóbal ; Weintraub, Andres A Progressive Hedging approach to solve harvest scheduling problem under climate change Journal Article pp. 1–29, 2016. @article{bachmatiuk_progressive_2016, title = {A Progressive Hedging approach to solve harvest scheduling problem under climate change}, author = {Bachmatiuk, Joanna and Garcia-gonzalo, Jordi and Barreiro, Susana and Pais, Crist\'{o}bal and Weintraub, Andres}, year = {2016}, date = {2016-01-01}, pages = {1--29}, abstract = {Forest planning needs to consider several elements of uncertainty, such as prices. A new element of uncertainty is the influence of climate change that impacts forest growth, occurrence of wildfire and other natural disturbances. In many cases, uncertainty is included in planning models in the form of scenarios. In this paper we address the problem of harvest planning considering uncertainty of climate change, which affects tree growth. We develop a solution approach for this problem for a eucalyptus forest with 1000 stands located in central Portugal. We anticipate expected future conditions by considering 32 climate scenarios. Each climate scenario leads to a scenario of tree growth. In this paper we develop a mixed integer programming formulation where the stochastic problem is represented by satisfying the set of constraints that represent the forest planning problem for each scenario, and adding the non-anticipativity constraints that link all scenarios (i.e. extensive form). Decision variables define which stands must be cut in each period in order to maximize expected net profit. The whole set of constraints can lead to a very large problem that can only be solved by decomposition into scenarios. We solve the problem using Progressive Hedging (PH) algorithm (Rockafeller and Wets, 1987) which decomposes the problem into scenarios. We compare both approaches, the extensive form and PH, using the described forest problem and testing 10 scenarios trees. We consider planning with and without spatial adjacency constraints.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Forest planning needs to consider several elements of uncertainty, such as prices. A new element of uncertainty is the influence of climate change that impacts forest growth, occurrence of wildfire and other natural disturbances. In many cases, uncertainty is included in planning models in the form of scenarios. In this paper we address the problem of harvest planning considering uncertainty of climate change, which affects tree growth. We develop a solution approach for this problem for a eucalyptus forest with 1000 stands located in central Portugal. We anticipate expected future conditions by considering 32 climate scenarios. Each climate scenario leads to a scenario of tree growth. In this paper we develop a mixed integer programming formulation where the stochastic problem is represented by satisfying the set of constraints that represent the forest planning problem for each scenario, and adding the non-anticipativity constraints that link all scenarios (i.e. extensive form). Decision variables define which stands must be cut in each period in order to maximize expected net profit. The whole set of constraints can lead to a very large problem that can only be solved by decomposition into scenarios. We solve the problem using Progressive Hedging (PH) algorithm (Rockafeller and Wets, 1987) which decomposes the problem into scenarios. We compare both approaches, the extensive form and PH, using the described forest problem and testing 10 scenarios trees. We consider planning with and without spatial adjacency constraints. |
Rau, Tomás A Covariate Balancing Kernel Matching Estimator Inproceedings 2016 Latin American Workshop in Econometrics, pp. 30, Montevideo, Uruguay, 2016. @inproceedings{rau_covariate_2016, title = {A Covariate Balancing Kernel Matching Estimator}, author = {Rau, Tom\'{a}s}, url = {https://editorialexpress.com/cgi-bin/conference/download.cgi?db_name=ESWC2015&paper_id=516}, year = {2016}, date = {2016-01-01}, booktitle = {2016 Latin American Workshop in Econometrics}, pages = {30}, address = {Montevideo, Uruguay}, abstract = {This paper proposes a bandwidth selection procedure in Kernel-Based Matching Es- timators that, at the same time, improves covariate balance, and decrease the bias of average treatment effects estimators. The method optimizes covariate balance by min- imizing the sample average of a covariate balancing moment condition related to the Hotelling's T-squared statistics of differences between the means of treated and control units, after the match. The estimation of the optimal bandwidth follows a generalized method of moments. Monte Carlo evidence shows that Kernel Matching with this optimal bandwidth performs very well regarding covariate balance and mean squared error. We provide large sample properties of Kernel Matching and a sample analog of the population marginal variance.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This paper proposes a bandwidth selection procedure in Kernel-Based Matching Es- timators that, at the same time, improves covariate balance, and decrease the bias of average treatment effects estimators. The method optimizes covariate balance by min- imizing the sample average of a covariate balancing moment condition related to the Hotelling's T-squared statistics of differences between the means of treated and control units, after the match. The estimation of the optimal bandwidth follows a generalized method of moments. Monte Carlo evidence shows that Kernel Matching with this optimal bandwidth performs very well regarding covariate balance and mean squared error. We provide large sample properties of Kernel Matching and a sample analog of the population marginal variance. |
Bozkurt, Deniz ; Rondanelli, Roberto ; Garreaud, René ; Arriagada, Andrés Impact of Warmer Eastern Tropical Pacific SST on the March 2015 Atacama Floods Journal Article Monthly Weather Review, 144 (11), pp. 4441–4460, 2016, ISSN: 0027-0644. @article{bozkurt_impact_2016, title = {Impact of Warmer Eastern Tropical Pacific SST on the March 2015 Atacama Floods}, author = {Bozkurt, Deniz and Rondanelli, Roberto and Garreaud, Ren\'{e} and Arriagada, Andr\'{e}s}, url = {http://journals.ametsoc.org/doi/10.1175/MWR-D-16-0041.1}, doi = {10.1175/MWR-D-16-0041.1}, issn = {0027-0644}, year = {2016}, date = {2016-01-01}, journal = {Monthly Weather Review}, volume = {144}, number = {11}, pages = {4441--4460}, abstract = {NorthernChile hosts the driest place onEarth in theAtacamaDesert. Nonetheless, an extreme precipitation event affected the region on 24\textendash26 March 2015 with 1-day accumulated precipitation exceeding 40mm in several locations and hourly mean rainfall rates higher than 10mmh21, producing floods and resulting in ca- sualties and significant damage. The event is analyzed using ERA-Interim, surface station data, sounding ob- servations, andsatellite-basedradar.Twomain conditions favorable for precipitationwerepresent at the timeof the event: (i) a cutoff low(COL) off the coast of northern Chile and (ii) positive sea surface temperature (SST) anomalies over the eastern tropicalPacific. The circulation driven by theCOLwas strong but not extraordinary. Regional ClimateModel, version4 (RegCM4), is used to test the sensitivity of precipitation toSSTanomaliesby removing the warm SST anomaly in the eastern tropical Pacific. The cooler simulation produced very similar COL dry dynamics to that simulated in a control run (with observed SST), but suppressed the precipitation by 60%\textendash80%over northern Chile and 100%in parts of the Atacama Desert due to the decreased availability of precipitable water. The results indicate that the warm SST anomaly over the eastern Pacific, favored by the onset ofElNi\~{n}o 2015/16,was instrumental to the extreme precipitation event by providing ananomalous source of water vapor transported to Atacama by the circulation ahead of the COL.}, keywords = {}, pubstate = {published}, tppubtype = {article} } NorthernChile hosts the driest place onEarth in theAtacamaDesert. Nonetheless, an extreme precipitation event affected the region on 24–26 March 2015 with 1-day accumulated precipitation exceeding 40mm in several locations and hourly mean rainfall rates higher than 10mmh21, producing floods and resulting in ca- sualties and significant damage. The event is analyzed using ERA-Interim, surface station data, sounding ob- servations, andsatellite-basedradar.Twomain conditions favorable for precipitationwerepresent at the timeof the event: (i) a cutoff low(COL) off the coast of northern Chile and (ii) positive sea surface temperature (SST) anomalies over the eastern tropicalPacific. The circulation driven by theCOLwas strong but not extraordinary. Regional ClimateModel, version4 (RegCM4), is used to test the sensitivity of precipitation toSSTanomaliesby removing the warm SST anomaly in the eastern tropical Pacific. The cooler simulation produced very similar COL dry dynamics to that simulated in a control run (with observed SST), but suppressed the precipitation by 60%–80%over northern Chile and 100%in parts of the Atacama Desert due to the decreased availability of precipitable water. The results indicate that the warm SST anomaly over the eastern Pacific, favored by the onset ofElNiño 2015/16,was instrumental to the extreme precipitation event by providing ananomalous source of water vapor transported to Atacama by the circulation ahead of the COL. |
Karna, Nabin Kumar; Oyarzua, Elton; Walther, Jens H; Zambrano, Harvey A Effect of the meniscus contact angle during early regimes of spontaneous imbibition in nanochannels Journal Article Phys. Chem. Chem. Phys., 18 (47), pp. 31997–32001, 2016, ISSN: 1463-9076. @article{karna_effect_2016, title = {Effect of the meniscus contact angle during early regimes of spontaneous imbibition in nanochannels}, author = {Nabin Kumar Karna and Elton Oyarzua and Jens H Walther and Harvey A Zambrano}, url = {http://xlink.rsc.org/?DOI=C6CP06155A}, doi = {10.1039/C6CP06155A}, issn = {1463-9076}, year = {2016}, date = {2016-01-01}, journal = {Phys. Chem. Chem. Phys.}, volume = {18}, number = {47}, pages = {31997--32001}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Schmidt, Iván; Siddikov, M Production of pentaquarks in $pA$-collisions Journal Article Phys. Rev. D, 93 (9), pp. 094005, 2016. @article{schmidt_production_2016, title = {Production of pentaquarks in $pA$-collisions}, author = {Iv\'{a}n Schmidt and M Siddikov}, url = {https://link.aps.org/doi/10.1103/PhysRevD.93.094005}, doi = {10.1103/PhysRevD.93.094005}, year = {2016}, date = {2016-01-01}, journal = {Phys. Rev. D}, volume = {93}, number = {9}, pages = {094005}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2015 |
Levin, Eugene; Lipatov, Lev; Siddikov, Marat Semiclassical solution to the BFKL equation with massive gluons Journal Article The European Physical Journal C, 75 (11), pp. 558, 2015, ISSN: 1434-6052. @article{levin_semiclassical_2015, title = {Semiclassical solution to the BFKL equation with massive gluons}, author = {Eugene Levin and Lev Lipatov and Marat Siddikov}, url = {https://doi.org/10.1140/epjc/s10052-015-3777-y}, doi = {10.1140/epjc/s10052-015-3777-y}, issn = {1434-6052}, year = {2015}, date = {2015-01-01}, journal = {The European Physical Journal C}, volume = {75}, number = {11}, pages = {558}, abstract = {In this paper we proceed to study the high energy behavior of scattering amplitudes in a simple field model, with the Higgs mechanism for the gauge boson mass. The spectrum of the j-plane singularities of the t-channel partial waves and the corresponding eigenfunctions of the BFKL equation in leading $$textbackslashbackslashtext log(1/x)$$ log ( 1 / x ) approximation were previously calculated numerically. Here we develop a semiclassical approach to investigate the influence of the exponential decrease of the impact parameter dependence existing in this model, on the high energy asymptotic behavior of the scattering amplitude. This approach is much simpler than our earlier numerical calculations, and it reproduces those results. The analytical (semi-analytical) solutions which have been found in the approximation can be used to incorporate correctly the large impact parameter behavior in the framework of CGC/saturation approach. This behavior is interesting as it provides the high energy amplitude for the electroweak theory, which can be measured experimentally.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper we proceed to study the high energy behavior of scattering amplitudes in a simple field model, with the Higgs mechanism for the gauge boson mass. The spectrum of the j-plane singularities of the t-channel partial waves and the corresponding eigenfunctions of the BFKL equation in leading $$textbackslashbackslashtext log(1/x)$$ log ( 1 / x ) approximation were previously calculated numerically. Here we develop a semiclassical approach to investigate the influence of the exponential decrease of the impact parameter dependence existing in this model, on the high energy asymptotic behavior of the scattering amplitude. This approach is much simpler than our earlier numerical calculations, and it reproduces those results. The analytical (semi-analytical) solutions which have been found in the approximation can be used to incorporate correctly the large impact parameter behavior in the framework of CGC/saturation approach. This behavior is interesting as it provides the high energy amplitude for the electroweak theory, which can be measured experimentally. |
2014 |
Araya-Secchi, Raul; Perez-Acle, Tomas; Kang, Seung-gu; Huynh, Tien; Bernardin, Alejandro; Escalona, Yerko; Garate, Jose-Antonio; í, Agustin~D. Mart; í, Isaac~E. Garc; á, Juan~C. S; Zhou, Ruhong Characterization of a Novel Water Pocket Inside the Human Cx26 Hemichannel Structure Journal Article Biophysical Journal, 107 (3), pp. 599–612, 2014. @article{ArayaSecchi2014, title = {Characterization of a Novel Water Pocket Inside the Human Cx26 Hemichannel Structure}, author = {Raul Araya-Secchi and Tomas Perez-Acle and Seung-gu Kang and Tien Huynh and Alejandro Bernardin and Yerko Escalona and Jose-Antonio Garate and Agustin~D. Mart \'{i} and Isaac~E. Garc \'{i} and Juan~C. S \'{a} and Ruhong Zhou}, url = {https://doi.org/10.1016/j.bpj.2014.05.037}, doi = {10.1016/j.bpj.2014.05.037}, year = {2014}, date = {2014-08-01}, journal = {Biophysical Journal}, volume = {107}, number = {3}, pages = {599--612}, publisher = {Elsevier BV}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Wachter, Javier ; Gutiérrez, Gonzalo ; Zúñiga, Alejandro ; Palma, Rodrigo Buckling of Cu-Zr-based metallic glasses nanowires: Molecular dynamics study of surface effects Journal Article Journal of Materials Science, 49 (23), pp. 8051–8056, 2014, ISSN: 15734803. @article{wachter_buckling_2014, title = {Buckling of Cu-Zr-based metallic glasses nanowires: Molecular dynamics study of surface effects}, author = {Wachter, Javier and Guti\'{e}rrez, Gonzalo and Z\'{u}\~{n}iga, Alejandro and Palma, Rodrigo}, doi = {10.1007/s10853-014-8512-9}, issn = {15734803}, year = {2014}, date = {2014-01-01}, journal = {Journal of Materials Science}, volume = {49}, number = {23}, pages = {8051--8056}, abstract = {The phenomenon of buckling in Cu45Zr45Al10 metallic glass nanowires with different slenderness ratios was studied by means of molecular dynamics simulation. The values of critical stress versus slenderness ratio for two nanowire diameters were obtained. We analyzed the results within the framework of the modified Euler theory of buckling, obtaining values for the surface elastic modulus and the residual surface stress for the two different diam- eters. Our results show that the Cu45Zr45Al10 metallic glass in nanometric size become stiffer and exhibits a lower Young's modulus than that of a bulk sample.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The phenomenon of buckling in Cu45Zr45Al10 metallic glass nanowires with different slenderness ratios was studied by means of molecular dynamics simulation. The values of critical stress versus slenderness ratio for two nanowire diameters were obtained. We analyzed the results within the framework of the modified Euler theory of buckling, obtaining values for the surface elastic modulus and the residual surface stress for the two different diam- eters. Our results show that the Cu45Zr45Al10 metallic glass in nanometric size become stiffer and exhibits a lower Young's modulus than that of a bulk sample. |
2012 |
Rangarajan, Ramsharan ; Lew, Adrian J Universal Meshes: A new paradigm for computing with nonconforming triangulations Journal Article Wiley Online Library, pp. 1–14, 2012. @article{rangarajan_universal_2012, title = {Universal Meshes: A new paradigm for computing with nonconforming triangulations}, author = {Rangarajan, Ramsharan and Lew, Adrian J.}, url = {http://arxiv.org/abs/1201.4903}, doi = {10.1002/nme}, year = {2012}, date = {2012-01-01}, journal = {Wiley Online Library}, pages = {1--14}, abstract = {We describe a method for discretizing planar C2-regular domains immersed in non-conforming triangulations. The method consists in constructing mappings from triangles in a background mesh to curvilinear ones that conform exactly to the immersed domain. Constructing such a map relies on a novel way of parameterizing the immersed boundary over a collection of nearby edges with its closest point projection. By interpolating the mappings to curvilinear triangles at select points, we recover isoparametric mappings for the immersed domain defined over the background mesh. Indeed, interpolating the constructed mappings just at the vertices of the background mesh yields a fast meshing algorithm that involves only perturbing a few vertices near the boundary. For the discretization of a curved domain to be robust, we have to impose restrictions on the background mesh. Conversely, these restrictions define a family of domains that can be discretized with a given background mesh. We then say that the background mesh is a universal mesh for such a family of domains. The notion of universal meshes is particularly useful in free/moving boundary problems because the same background mesh can serve as the universal mesh for the evolving domain for time intervals that are independent of the time step. Hence it facilitates a framework for finite element calculations over evolving domains while using a fixed background mesh. Furthermore, since the evolving geometry can be approximated with any desired order, numerical solutions can be computed with high-order accuracy. We demonstrate these ideas with various numerical examples.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We describe a method for discretizing planar C2-regular domains immersed in non-conforming triangulations. The method consists in constructing mappings from triangles in a background mesh to curvilinear ones that conform exactly to the immersed domain. Constructing such a map relies on a novel way of parameterizing the immersed boundary over a collection of nearby edges with its closest point projection. By interpolating the mappings to curvilinear triangles at select points, we recover isoparametric mappings for the immersed domain defined over the background mesh. Indeed, interpolating the constructed mappings just at the vertices of the background mesh yields a fast meshing algorithm that involves only perturbing a few vertices near the boundary. For the discretization of a curved domain to be robust, we have to impose restrictions on the background mesh. Conversely, these restrictions define a family of domains that can be discretized with a given background mesh. We then say that the background mesh is a universal mesh for such a family of domains. The notion of universal meshes is particularly useful in free/moving boundary problems because the same background mesh can serve as the universal mesh for the evolving domain for time intervals that are independent of the time step. Hence it facilitates a framework for finite element calculations over evolving domains while using a fixed background mesh. Furthermore, since the evolving geometry can be approximated with any desired order, numerical solutions can be computed with high-order accuracy. We demonstrate these ideas with various numerical examples. |
0000 |
Aravena, Daniel Ab Initio Prediction of Tunneling Relaxation Times and Effective Demagnetization Barriers in Kramers Lanthanide Single-Molecule Magnets Journal Article The Journal of Physical Chemistry Letters, 0 (0), pp. 5327-5333, 0000, (PMID: 30149712). @article{doi:10.1021/acs.jpclett.8b02359, title = {Ab Initio Prediction of Tunneling Relaxation Times and Effective Demagnetization Barriers in Kramers Lanthanide Single-Molecule Magnets}, author = {Daniel Aravena}, url = {https://doi.org/10.1021/acs.jpclett.8b02359}, doi = {10.1021/acs.jpclett.8b02359}, year = {0000}, date = {0000-01-01}, journal = {The Journal of Physical Chemistry Letters}, volume = {0}, number = {0}, pages = {5327-5333}, abstract = {Single-molecule magnets (SMMs) are promising candidates for molecule-based quantum information devices. Their main limitation is their cryogenic operative temperature. To achieve devices performing at higher temperatures, demagnetization mechanisms must be suppressed by chemical tuning. Electronic structure calculations can provide useful information to rationalize SMM behavior, but they do not provide a direct prediction for the key experimental parameters describing magnetic relaxation (i.e., tunneling relaxation time (τQT) and effective demagnetization barrier (Ueff)). In this Letter, a first-principles model is proposed to predict τQT and Ueff for mononuclear, half-integer spin SMMs, allowing direct comparison with experiment. Model accuracy was assessed against experimental data for 18 mononuclear LnIII complexes (15 DyIII and 3 ErIII) and applied to 3 of the current best-performing SMMs, correctly predicting nontrivial relaxation pathways. The model shows that the combination of single-ion anisotropy and spin\textendashspin dipolar coupling can account for the major part of tunneling demagnetization for the studied systems.}, note = {PMID: 30149712}, keywords = {}, pubstate = {published}, tppubtype = {article} } Single-molecule magnets (SMMs) are promising candidates for molecule-based quantum information devices. Their main limitation is their cryogenic operative temperature. To achieve devices performing at higher temperatures, demagnetization mechanisms must be suppressed by chemical tuning. Electronic structure calculations can provide useful information to rationalize SMM behavior, but they do not provide a direct prediction for the key experimental parameters describing magnetic relaxation (i.e., tunneling relaxation time (τQT) and effective demagnetization barrier (Ueff)). In this Letter, a first-principles model is proposed to predict τQT and Ueff for mononuclear, half-integer spin SMMs, allowing direct comparison with experiment. Model accuracy was assessed against experimental data for 18 mononuclear LnIII complexes (15 DyIII and 3 ErIII) and applied to 3 of the current best-performing SMMs, correctly predicting nontrivial relaxation pathways. The model shows that the combination of single-ion anisotropy and spin–spin dipolar coupling can account for the major part of tunneling demagnetization for the studied systems. |
Pizarro, Ana; Abarca, Gabriel; Gutiérrez-Cerón, Cristian; Cortés-Arriagada, Diego; Bernardi, Fabiano; Berrios, Cristhian; Silva, Juan F; Rezende, Marcos C; Zagal, José H; Oñate, Rubén; Ponce, Ingrid ACS Catalysis, 0 (0), pp. 8406-8419, 0000. @article{doi:10.1021/acscatal.8b01479, title = {Building Pyridinium Molecular Wires as Axial Ligands for Tuning the Electrocatalytic Activity of Iron Phthalocyanines for the Oxygen Reduction Reaction}, author = {Ana Pizarro and Gabriel Abarca and Cristian Guti\'{e}rrez-Cer\'{o}n and Diego Cort\'{e}s-Arriagada and Fabiano Bernardi and Cristhian Berrios and Juan F Silva and Marcos C Rezende and Jos\'{e} H Zagal and Rub\'{e}n O\~{n}ate and Ingrid Ponce}, url = {https://doi.org/10.1021/acscatal.8b01479}, doi = {10.1021/acscatal.8b01479}, year = {0000}, date = {0000-01-01}, journal = {ACS Catalysis}, volume = {0}, number = {0}, pages = {8406-8419}, abstract = {We have been able to “tune” the electrocatalytic activity of iron phthalocyanine (FePc) and iron hexadodecachlorophthalocyanine (16(Cl)FePc) for the oxygen reduction reaction (ORR) by manipulating the “pull effect” of pyridinium molecules axially bounded to the phthalocyanine complexes (FePcs). These axial ligands play both the role of molecular anchors and also of molecular wires. The axial ligands also affect the reactivity of the Fe metal center in the phthalocyanine. The “pull effect” originates from the positive charge located on the pyridinium core. We have explored the influence of the core positions (Up or Down), in two structural pyridiniums isomers on the activity of FePc and 16(Cl)FePc for the ORR. Of all self-assembled catalysts tested, the highest catalytic activity was exhibited by the Au(111)/Up/FePc system. XPS measurements and DFT calculations showed that it is possible to tailor the FePc\textendashN(pyridiniums) Fe\textendashO2 binding energies, by changing the core positions and affecting the “pull effect” of pyridiniums. This affects directly the catalytic activity of FePcs. The plot of activity as (log I)E versus the calculated Fe\textendashO2 binding energies gives an activity volcano correlation, indicating that an optimum binding energy of O2 with the Fe center provides the highest activity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We have been able to “tune” the electrocatalytic activity of iron phthalocyanine (FePc) and iron hexadodecachlorophthalocyanine (16(Cl)FePc) for the oxygen reduction reaction (ORR) by manipulating the “pull effect” of pyridinium molecules axially bounded to the phthalocyanine complexes (FePcs). These axial ligands play both the role of molecular anchors and also of molecular wires. The axial ligands also affect the reactivity of the Fe metal center in the phthalocyanine. The “pull effect” originates from the positive charge located on the pyridinium core. We have explored the influence of the core positions (Up or Down), in two structural pyridiniums isomers on the activity of FePc and 16(Cl)FePc for the ORR. Of all self-assembled catalysts tested, the highest catalytic activity was exhibited by the Au(111)/Up/FePc system. XPS measurements and DFT calculations showed that it is possible to tailor the FePc–N(pyridiniums) Fe–O2 binding energies, by changing the core positions and affecting the “pull effect” of pyridiniums. This affects directly the catalytic activity of FePcs. The plot of activity as (log I)E versus the calculated Fe–O2 binding energies gives an activity volcano correlation, indicating that an optimum binding energy of O2 with the Fe center provides the highest activity. |
Banegas-Luna, Antonio Jesús; Cerón-Carrasco, José Pedro; Puertas-Martin, Savins; Perez-Sanchez, Horacio BRUSELAS: HPC generic and customizable software architecture for 3D ligand-based virtual screening of large molecular databases Journal Article Journal of Chemical Information and Modeling, 0 (ja), pp. null, 0000. @article{doi:10.1021/acs.jcim.9b00279, title = {BRUSELAS: HPC generic and customizable software architecture for 3D ligand-based virtual screening of large molecular databases}, author = {Antonio Jes\'{u}s Banegas-Luna and Jos\'{e} Pedro Cer\'{o}n-Carrasco and Savins Puertas-Martin and Horacio Perez-Sanchez}, url = {https://doi.org/10.1021/acs.jcim.9b00279}, doi = {10.1021/acs.jcim.9b00279}, year = {0000}, date = {0000-01-01}, journal = {Journal of Chemical Information and Modeling}, volume = {0}, number = {ja}, pages = {null}, abstract = {BRUSELAS (Balanced Rapid and Unrestricted Server for Extensive Ligand-Aimed Screening) is a novel, highly efficient web software architecture for 3D shape and pharmacophore searches in off the cuff libraries. A wide panel of shape and pharmacophore similarity algorithms are combined to avoid unbiased results while yielding consensus scoring functions. To evaluate its reliability, BRUSELAS was tested against other similar servers (e.g. USR-VS, SwissSimilarity, ChemMapper) to search for potential antidiabetic drugs. A web tool is developed for users to customize their tasks and is accessible free of any charge or login at http://bio-hpc.ucam.edu/Bruselas. Source code is available on request.}, keywords = {}, pubstate = {published}, tppubtype = {article} } BRUSELAS (Balanced Rapid and Unrestricted Server for Extensive Ligand-Aimed Screening) is a novel, highly efficient web software architecture for 3D shape and pharmacophore searches in off the cuff libraries. A wide panel of shape and pharmacophore similarity algorithms are combined to avoid unbiased results while yielding consensus scoring functions. To evaluate its reliability, BRUSELAS was tested against other similar servers (e.g. USR-VS, SwissSimilarity, ChemMapper) to search for potential antidiabetic drugs. A web tool is developed for users to customize their tasks and is accessible free of any charge or login at http://bio-hpc.ucam.edu/Bruselas. Source code is available on request. |
Rojas-Nunez, Javier; Gonzalez, Rafael I I; Bringa, Eduardo M; Allende, Sebastian; Sepúlveda, Pamela; Arancibia-Miranda, Nicolás; Baltazar, Samuel E Towards Controlled Morphology of FeCu Nanoparticles: Cu Concentration and Size Effects Journal Article The Journal of Physical Chemistry C, 0 (ja), pp. null, 0000. @article{doi:10.1021/acs.jpcc.7b11556, title = {Towards Controlled Morphology of FeCu Nanoparticles: Cu Concentration and Size Effects}, author = {Javier Rojas-Nunez and Rafael I I Gonzalez and Eduardo M Bringa and Sebastian Allende and Pamela Sep\'{u}lveda and Nicol\'{a}s Arancibia-Miranda and Samuel E Baltazar}, url = {https://doi.org/10.1021/acs.jpcc.7b11556}, doi = {10.1021/acs.jpcc.7b11556}, year = {0000}, date = {0000-01-01}, journal = {The Journal of Physical Chemistry C}, volume = {0}, number = {ja}, pages = {null}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Walter, Rabanal-León; Alejandro, Vásquez-Espinal; Osvaldo, Yañez; Ricardo, Pino-Rios; Ramiro, Arratia-Pérez; Luis, Alvarez-Thon; Juan, Torres-Vega; William, Tiznado Aromaticity of [M3(µ‐X)3X6]0/2‐ (M = Re and Tc Journal Article European Journal of Inorganic Chemistry, 0 (ja), 0000. @article{doi:10.1002/ejic.201800339, title = {Aromaticity of [M3(µ‐X)3X6]0/2‐ (M = Re and Tc}, author = {Rabanal-Le\'{o}n Walter and V\'{a}squez-Espinal Alejandro and Ya\~{n}ez Osvaldo and Pino-Rios Ricardo and Arratia-P\'{e}rez Ramiro and Alvarez-Thon Luis and Torres-Vega Juan and Tiznado William}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ejic.201800339}, doi = {10.1002/ejic.201800339}, journal = {European Journal of Inorganic Chemistry}, volume = {0}, number = {ja}, abstract = {We present new evidence that supports the aromatic character of the clusters with the formula: [M3(µ‐X)3X6]0/2‐ (M = Re and Tc}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present new evidence that supports the aromatic character of the clusters with the formula: [M3(µ‐X)3X6]0/2‐ (M = Re and Tc |
Luis, Lemus; E, Díaz Daniel; Leonel, Llanos; Pablo, Arce; Romina, Lorca; Juan, Guerrero; Juan, Costamagna; Daniel, Aravena; Guillermo, Ferraudi; Allen, Oliver; Graham, Lappin Alexander Chemistry – A European Journal, 0 (ja), 0000. @article{luis_steric_nodate, title = {Steric and electronic factors affecting the conformation of bimetallic Cu(I) complexes. Effect of the aliphatic spacer of tetracoordinating Schiff base ligands.}, author = {Lemus Luis and D\'{i}az Daniel E and Llanos Leonel and Arce Pablo and Lorca Romina and Guerrero Juan and Costamagna Juan and Aravena Daniel and Ferraudi Guillermo and Oliver Allen and Lappin Alexander Graham}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201802290}, doi = {10.1002/chem.201802290}, journal = {Chemistry \textendash A European Journal}, volume = {0}, number = {ja}, abstract = {A family of six homoleptic [CuI(Ln)]2(ClO4)2 and six heteroleptic [CuI(Ln)(PPh3)2]2(ClO4)2 bimetallic complexes, where Ln are bis‐Schiff base ligands with alkyl spacers of variable length (n= 2‐7 ‐CH2‐), were prepared to evaluate the role of the spacer on the formation of helicates or mesocates. In the homoleptic series, spectroscopic and theoretical studies indicate that preferences for a conformation are based on energetic parameters, mainly, the establishment of non‐covalent interactions. The odd‐even nature of the spacers pre‐conditions the superposition of the aromatic rings to allow the juxtaposition necessary for non‐covalent interactions, while the increase of the length reduces the strength of such interactions. Consequently, complexes with even‐spacers of short length were identified as helicates in solution, [CuI(Ln)]22+ (n=2,4). Complexes [CuI(Ln)]22+ (n=3‐7) dissociate in solution to produce the monometallic complexes in equilibrium, [CuI(Ln)]+. The stability of the bimetallic species is discussed in terms of their conformations. The set of heteroleptic complexes was prepared to evaluate the reach of the 'odd‐even rule' in solid, which is based on the 'zig‐zag' arrangements of the spacers. Based on crystallographic information, 'S' and 'C'‐type conformations of Ln are related to even and odd spacers, respectively. This trend is considered in addition to other factors to explain preferences for either a mesocate or helicate conformation in the homoleptic series.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A family of six homoleptic [CuI(Ln)]2(ClO4)2 and six heteroleptic [CuI(Ln)(PPh3)2]2(ClO4)2 bimetallic complexes, where Ln are bis‐Schiff base ligands with alkyl spacers of variable length (n= 2‐7 ‐CH2‐), were prepared to evaluate the role of the spacer on the formation of helicates or mesocates. In the homoleptic series, spectroscopic and theoretical studies indicate that preferences for a conformation are based on energetic parameters, mainly, the establishment of non‐covalent interactions. The odd‐even nature of the spacers pre‐conditions the superposition of the aromatic rings to allow the juxtaposition necessary for non‐covalent interactions, while the increase of the length reduces the strength of such interactions. Consequently, complexes with even‐spacers of short length were identified as helicates in solution, [CuI(Ln)]22+ (n=2,4). Complexes [CuI(Ln)]22+ (n=3‐7) dissociate in solution to produce the monometallic complexes in equilibrium, [CuI(Ln)]+. The stability of the bimetallic species is discussed in terms of their conformations. The set of heteroleptic complexes was prepared to evaluate the reach of the 'odd‐even rule' in solid, which is based on the 'zig‐zag' arrangements of the spacers. Based on crystallographic information, 'S' and 'C'‐type conformations of Ln are related to even and odd spacers, respectively. This trend is considered in addition to other factors to explain preferences for either a mesocate or helicate conformation in the homoleptic series. |
Montecinos, Rodrigo; Diaz-Wilson, Fernanda; Bravo-Sepulveda, Alexis; Salas, Cristian O; Recabarren-Gajardo, Gonzalo; Nome, Faruk Investigation about the complexation of trimethylammonium-derived pillar[5]arene with indole and azaindole derivatives Journal Article Journal of Physical Organic Chemistry, 0 (0), pp. e3889, 0000, (e3889 POC-17-0270.R1). @article{doi:10.1002/poc.3889, title = {Investigation about the complexation of trimethylammonium-derived pillar[5]arene with indole and azaindole derivatives}, author = {Rodrigo Montecinos and Fernanda Diaz-Wilson and Alexis Bravo-Sepulveda and Cristian O Salas and Gonzalo Recabarren-Gajardo and Faruk Nome}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/poc.3889}, doi = {10.1002/poc.3889}, journal = {Journal of Physical Organic Chemistry}, volume = {0}, number = {0}, pages = {e3889}, abstract = {Abstract Indoles and azaindoles are very interesting heterocycles found in naturally occurring and synthetic molecules exhibiting several biological activities associated with its physicochemical properties. Here, we report a study about the inclusion complex formation between trimethylammonium-derived pillar[5]arene (P5A) with indole and azaindole derivatives by NMR and molecular dynamics simulations. Our results indicate that indole forms the most stable inclusion complex of the hosts, with its benzene fragment incorporated near to the centre of the cavity. On the other hand, 5-azaindole presents a weaker interaction with P5A, orienting preferentially the pyrrole moiety toward the host cavity. 7-Azaindole switches between two conformations with the pyridine fragment incorporated inside the cavity. Based on these results, we believe these preliminary study of how the guest structure modifies the structure of the inclusion complexes, and the molecular recognition can be further used in the preparation of new functional supramolecular systems including drug delivery systems.}, note = {e3889 POC-17-0270.R1}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Indoles and azaindoles are very interesting heterocycles found in naturally occurring and synthetic molecules exhibiting several biological activities associated with its physicochemical properties. Here, we report a study about the inclusion complex formation between trimethylammonium-derived pillar[5]arene (P5A) with indole and azaindole derivatives by NMR and molecular dynamics simulations. Our results indicate that indole forms the most stable inclusion complex of the hosts, with its benzene fragment incorporated near to the centre of the cavity. On the other hand, 5-azaindole presents a weaker interaction with P5A, orienting preferentially the pyrrole moiety toward the host cavity. 7-Azaindole switches between two conformations with the pyridine fragment incorporated inside the cavity. Based on these results, we believe these preliminary study of how the guest structure modifies the structure of the inclusion complexes, and the molecular recognition can be further used in the preparation of new functional supramolecular systems including drug delivery systems. |
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