The particularly great practical importance of modern physical geography and, in particular, landscape science, is first of all manifested in the detection and study of the resource potential of landscapes, as well as...The particularly great practical importance of modern physical geography and, in particular, landscape science, is first of all manifested in the detection and study of the resource potential of landscapes, as well as in the optimization of the environment. The resource potential, on the other hand, greatly depends on the balance of substance and energy exchange in the natural resources, i.e. the energy of the landscape. In this case, one of the important things is to study the functioning of natural-territorial complexes (NTC). Through it, it is possible and relatively easy to explain, model and, most importantly, predict many complex processes taking place in NTC, including the role of landscape energy balance in increasing the productivity and yield of agro-landscapes, which was the first attempt to research this problem in Georgia.展开更多
The fast dynamic properties of the surface of metallic glasses(MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simula...The fast dynamic properties of the surface of metallic glasses(MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simulation models and laboratory-made samples, the atomic-scale behaviors of the fast surface dynamics of MGs in experiments remain uncertain. Herein, we prepared model MG films with notable variations in thermal stability using a recently developed efficient annealing protocol, and investigated their atomic-scale dynamics systematically. We found that the dynamics of surface atoms remain invariant, whereas the difference in dynamical heterogeneity between surface and interior regions increases with the improvement of thermal stability. This can be associated with the more pronounced correlation between atomic activation energy spectra and depth from the surface in samples with higher thermal stability. In addition, dynamic anisotropy appears for surface atoms, and their transverse dynamics are faster than normal components, which can also be interpreted by activation energy spectra. Our results reveal the presence of strong liquid-like atomic dynamics confined to the surface of laboratory-made MGs, illuminating the underlying mechanisms for surface engineering design, such as cold joining by ultrasonic vibrations and superlattice growth.展开更多
High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 al...High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 alters the structure and stability of the canonical nucleosome(N) in a nonenzymatic,adenosine triphosphate-independent manner. As a result, the canonical nucleosome is converted to two stable, physically distinct nucleosome conformers. Although estrogen receptor(ER) does not bind to its consensus estrogen response element within a nucleosome, HMGB1 restructures the nucleosome to facilitate strong ER binding. The isolated HMGB1-restructured nucleosomes(N' and N'') remain stable and exhibit a number of characteristics that are distinctly different from the canonical nucleosome. These findings complement previous studies that showed(1) HMGB1 stimulates in vivo transcriptional activation at estrogen response elements and(2) knock down of HMGB1 expression by siR NA precipitously reduced transcriptional activation. The findings indicate that a major facet of the mechanism of HMGB1 action involves a restructuring of aspects of the nucleosome that appear to relax structural constraints within the nucleosome. The findings are extended to reveal the differences between ER and the other steroid hormone receptors. A working proposal outlines mechanisms that highlight the multiple facets that HMGB1 may utilize in restructuring the nucleosome.展开更多
The glass transition involves more than one dynamic relaxation mechanisms in supercooled liquids,such as α relaxation,slow β relaxation and fast β relaxation and so on.For the traditional theoretical system,α rela...The glass transition involves more than one dynamic relaxation mechanisms in supercooled liquids,such as α relaxation,slow β relaxation and fast β relaxation and so on.For the traditional theoretical system,α relaxation is believed mainly responsible for the nature of the glass transition as the beginning of the phenomenon.This idea,however,has been open to a big challenge since recent studies have indicated that slow β relaxation closely relates to α relaxation.Slow β relaxation determines the characteristics of α relaxation and is the precursor and the more microscopic base of glass transition behavior.In order to illuminate the significance of slow β relaxation in the fields of the glass transition and the structure of supercooled liquids,the accomplished progress is summarized from different aspects such as on the correlation between α relaxation and slow β relaxation,on the manner of α-slow β relaxation merging,on the energy landscape,on the excess wing and on the thermodynamically phenomenological models.The tendency of investigation in slow β relaxation is also evaluated.展开更多
We introduce a generalized numerical algorithm to construct the solution landscape,which is a pathway map consisting of all the stationary points and their connections.Based on the high-index optimizationbased shrinki...We introduce a generalized numerical algorithm to construct the solution landscape,which is a pathway map consisting of all the stationary points and their connections.Based on the high-index optimizationbased shrinking dimer(Hi OSD)method for gradient systems,a generalized high-index saddle dynamics(GHi SD)is proposed to compute any-index saddles of dynamical systems.Linear stability of the index-k saddle point can be proved for the GHi SD system.A combination of the downward search algorithm and the upward search algorithm is applied to systematically construct the solution landscape,which not only provides a powerful and efficient way to compute multiple solutions without tuning initial guesses,but also reveals the relationships between different solutions.Numerical examples,including a three-dimensional example and the phase field model,demonstrate the novel concept of the solution landscape by showing the connected pathway maps.展开更多
文摘The particularly great practical importance of modern physical geography and, in particular, landscape science, is first of all manifested in the detection and study of the resource potential of landscapes, as well as in the optimization of the environment. The resource potential, on the other hand, greatly depends on the balance of substance and energy exchange in the natural resources, i.e. the energy of the landscape. In this case, one of the important things is to study the functioning of natural-territorial complexes (NTC). Through it, it is possible and relatively easy to explain, model and, most importantly, predict many complex processes taking place in NTC, including the role of landscape energy balance in increasing the productivity and yield of agro-landscapes, which was the first attempt to research this problem in Georgia.
基金sponsored by the National Natural Science Foundation of China (Grant No. 52101201)supported by the National Natural Science Foundation of China (Grant No.T2325004)+2 种基金sponsored by the National Natural Science Foundation of China(Grant No. 51801046)the Natural Science Foundation of Chongqing,China (Grant No. cstc2021jcyj-msxm X0369)the Science Fund for Scientific and Technological Innovation Team of Shaanxi Province (Grant No. 2021TD-14)。
文摘The fast dynamic properties of the surface of metallic glasses(MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simulation models and laboratory-made samples, the atomic-scale behaviors of the fast surface dynamics of MGs in experiments remain uncertain. Herein, we prepared model MG films with notable variations in thermal stability using a recently developed efficient annealing protocol, and investigated their atomic-scale dynamics systematically. We found that the dynamics of surface atoms remain invariant, whereas the difference in dynamical heterogeneity between surface and interior regions increases with the improvement of thermal stability. This can be associated with the more pronounced correlation between atomic activation energy spectra and depth from the surface in samples with higher thermal stability. In addition, dynamic anisotropy appears for surface atoms, and their transverse dynamics are faster than normal components, which can also be interpreted by activation energy spectra. Our results reveal the presence of strong liquid-like atomic dynamics confined to the surface of laboratory-made MGs, illuminating the underlying mechanisms for surface engineering design, such as cold joining by ultrasonic vibrations and superlattice growth.
文摘High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 alters the structure and stability of the canonical nucleosome(N) in a nonenzymatic,adenosine triphosphate-independent manner. As a result, the canonical nucleosome is converted to two stable, physically distinct nucleosome conformers. Although estrogen receptor(ER) does not bind to its consensus estrogen response element within a nucleosome, HMGB1 restructures the nucleosome to facilitate strong ER binding. The isolated HMGB1-restructured nucleosomes(N' and N'') remain stable and exhibit a number of characteristics that are distinctly different from the canonical nucleosome. These findings complement previous studies that showed(1) HMGB1 stimulates in vivo transcriptional activation at estrogen response elements and(2) knock down of HMGB1 expression by siR NA precipitously reduced transcriptional activation. The findings indicate that a major facet of the mechanism of HMGB1 action involves a restructuring of aspects of the nucleosome that appear to relax structural constraints within the nucleosome. The findings are extended to reveal the differences between ER and the other steroid hormone receptors. A working proposal outlines mechanisms that highlight the multiple facets that HMGB1 may utilize in restructuring the nucleosome.
基金supported by the National Natural Science Foundation of China (Grant No.50801041)National Basic Research Program of China (Grant No.2007CB613901)Research Fund for the Doctoral Program of Higher Education of China (Grant No.200804221041)
文摘The glass transition involves more than one dynamic relaxation mechanisms in supercooled liquids,such as α relaxation,slow β relaxation and fast β relaxation and so on.For the traditional theoretical system,α relaxation is believed mainly responsible for the nature of the glass transition as the beginning of the phenomenon.This idea,however,has been open to a big challenge since recent studies have indicated that slow β relaxation closely relates to α relaxation.Slow β relaxation determines the characteristics of α relaxation and is the precursor and the more microscopic base of glass transition behavior.In order to illuminate the significance of slow β relaxation in the fields of the glass transition and the structure of supercooled liquids,the accomplished progress is summarized from different aspects such as on the correlation between α relaxation and slow β relaxation,on the manner of α-slow β relaxation merging,on the energy landscape,on the excess wing and on the thermodynamically phenomenological models.The tendency of investigation in slow β relaxation is also evaluated.
基金supported by National Natural Science Foundation of China(Grant No.11861130351)the support from the Elite Program of Computational and Applied Mathematics for Ph D Candidates of Peking University。
文摘We introduce a generalized numerical algorithm to construct the solution landscape,which is a pathway map consisting of all the stationary points and their connections.Based on the high-index optimizationbased shrinking dimer(Hi OSD)method for gradient systems,a generalized high-index saddle dynamics(GHi SD)is proposed to compute any-index saddles of dynamical systems.Linear stability of the index-k saddle point can be proved for the GHi SD system.A combination of the downward search algorithm and the upward search algorithm is applied to systematically construct the solution landscape,which not only provides a powerful and efficient way to compute multiple solutions without tuning initial guesses,but also reveals the relationships between different solutions.Numerical examples,including a three-dimensional example and the phase field model,demonstrate the novel concept of the solution landscape by showing the connected pathway maps.
