The Stokes shift response function, which is related to the time dependent solvation energy, is calculated with the dielectric response function and a novel expression of nonequilibrium solvation energy. In the deriva...The Stokes shift response function, which is related to the time dependent solvation energy, is calculated with the dielectric response function and a novel expression of nonequilibrium solvation energy. In the derivation, relationship between the polarization and the dielectric response function is used. With the dipole-in-a-sphere model applied to the system coumarin 343 and water as the solvent, encouraging agreement with the experimental data from Jimenez et al. is obtained [Nature 369, 471 （1994）].展开更多
Chrornophore structures inspired by natural green fluorescent protein （GFP） play an im- portant role in the field of bio-irnaging. In this work, photochemical properties of a new class of GFP-like chromophores are i...Chrornophore structures inspired by natural green fluorescent protein （GFP） play an im- portant role in the field of bio-irnaging. In this work, photochemical properties of a new class of GFP-like chromophores are investigated using computational approaches. Thermo- dynamically stable isomers are identified in vacuum and in solvent. Spectral Stokes shifts are computed and compared to experiments. An inverted solvatochromic shift between absorption and emission emerging in this new class of GFP-like chromophores is observed, and attributed to the stabilized charge transfer and inhibited rotational structural reorganization in solvent.展开更多
Hydrogen peroxide(H2O2)plays a significant role in regulating a variety of biological processes.Dysregulation of H2O2 can lead to various diseases.Although numerous fluorescent imaging probes for H2O2 have been report...Hydrogen peroxide(H2O2)plays a significant role in regulating a variety of biological processes.Dysregulation of H2O2 can lead to various diseases.Although numerous fluorescent imaging probes for H2O2 have been reported,the development of H2O2 ratiometric fluorescent probe with large Stokes shift remains rather limited.Such probes have shown distinct advantages,such as minimized interference from environment and improved signal-to noise ratio.In this work,we reported a new pyrene-based compound Py-VPB as H2O2 fluorescent probe in vitro.The probe demonstrated ratiometric detection behavior,large Stokes shift and large emission shift.In addition,the probe showed high sensitivity and selectivity towards H2O2 in vitro.Based on these excellent properties,we successfully applied Py-VPB to the visualization of exogenous and endogenous H2O2 in living cells.Cell imaging study also showed that our probe was localized in the mitochondria.We envision that the probe can provide a useful tool for unmasking the biological roles of mitochondrial H2O2 in living systems.展开更多
We consider semiconductor heterostructures in nanometric quantum wells, which as a consequence of the growth process display at the rugged interfaces fractal characteristics, and largely influence optical and transpor...We consider semiconductor heterostructures in nanometric quantum wells, which as a consequence of the growth process display at the rugged interfaces fractal characteristics, and largely influence optical and transport properties of the carriers system. The photoluminescence and excited photoluminescence spectra in such fractal conditions are theoretically analyzed, obtaining good agreement with the experimental results. The Stokes shift and linewidth are strongly dependent on the nonequilibrium thermomechanical-statistical state of the system. The Stokes shift has its origin in the presence of a gain region in the absorption spectrum, only present when the carriers system is in a statistical degenerate state.展开更多
This study identifies a decadal shift of summer surface air temperature （SAT） over Northeast Asia,including southeastern parts of Russia,Mongolia and northern China,around the mid-1990s.The results suggest that the ...This study identifies a decadal shift of summer surface air temperature （SAT） over Northeast Asia,including southeastern parts of Russia,Mongolia and northern China,around the mid-1990s.The results suggest that the SAT over the Northeast Asia experienced a significant warming after 1994 relative to that before 1993.This decadal shift also extends to northern China,and leads to a warmer summer over Northeast China and North China after the mid-1990s.The decadal warming over Northeast Asia is found to concur with the enhancement of South China rainfall around the mid-1990s.On the one hand,both the Northeast Asian SAT and South China rainfall exhibit this mid-1990s decadal shift only in summer,but not in other seasons.On the other hand,both the Northeast Asian SAT and South China rainfall exhibit this mid-1990s decadal shift not only in the summer seasonal mean,but also in each month of summer （June,July and August）.Furthermore,the decadal warming is found to result from an anticyclonic anomaly over Northeast Asia,which can be interpreted as the response to the increased precipitation over South China,according to previous numerical results.Thus,we conclude that the warming shift of summer Northeast Asian SAT around the mid-1990s was a remote response to the increased precipitation over South China.展开更多
Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous socia...Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous social and economic burden to the affected in- dividuals and their families, but is also a great scientific challenge. Currently 25-35 million people worldwide suffer from AD, the single largest cause of dementia in middle- to old-aged individuals. These numbers are projected to triple by 2050 if no treatment to prevent or reverse AD is developed.展开更多
Introduction：Alzheimer’s disease（AD）begins to develop decades prior to its clinical manifestation（Sperling et al.,2011）,and while it is the most common form of dementia,as of yet there is no cure.Two of the most...Introduction：Alzheimer’s disease（AD）begins to develop decades prior to its clinical manifestation（Sperling et al.,2011）,and while it is the most common form of dementia,as of yet there is no cure.Two of the most researched pathological features contributing to disease development are the extracellular amyloid plaques composed of amyloid-beta proteins（Aβ）and neurofibrillary tangles of tau proteins.Another feature of AD is the progression of early neuronal excitability/hyperactivity to silencing/hypoactivity（Palop and Mucke,2010）,展开更多
文摘The Stokes shift response function, which is related to the time dependent solvation energy, is calculated with the dielectric response function and a novel expression of nonequilibrium solvation energy. In the derivation, relationship between the polarization and the dielectric response function is used. With the dipole-in-a-sphere model applied to the system coumarin 343 and water as the solvent, encouraging agreement with the experimental data from Jimenez et al. is obtained [Nature 369, 471 （1994）].
基金supported by US National Science Foundation(CHE-1565520) to X. Lifunded by the STF at the University of Washingtonthe National Science Foundation (MRI-1624430).
文摘Chrornophore structures inspired by natural green fluorescent protein （GFP） play an im- portant role in the field of bio-irnaging. In this work, photochemical properties of a new class of GFP-like chromophores are investigated using computational approaches. Thermo- dynamically stable isomers are identified in vacuum and in solvent. Spectral Stokes shifts are computed and compared to experiments. An inverted solvatochromic shift between absorption and emission emerging in this new class of GFP-like chromophores is observed, and attributed to the stabilized charge transfer and inhibited rotational structural reorganization in solvent.
基金This work was supported by the Science Technology and Innovation Committee of Shenzhen Municipality(JCYJ20180507181654823)the National Natural Science Foundation of China(21778044)and Sichuan Science and Technology Program(2018JY0360).
文摘Hydrogen peroxide(H2O2)plays a significant role in regulating a variety of biological processes.Dysregulation of H2O2 can lead to various diseases.Although numerous fluorescent imaging probes for H2O2 have been reported,the development of H2O2 ratiometric fluorescent probe with large Stokes shift remains rather limited.Such probes have shown distinct advantages,such as minimized interference from environment and improved signal-to noise ratio.In this work,we reported a new pyrene-based compound Py-VPB as H2O2 fluorescent probe in vitro.The probe demonstrated ratiometric detection behavior,large Stokes shift and large emission shift.In addition,the probe showed high sensitivity and selectivity towards H2O2 in vitro.Based on these excellent properties,we successfully applied Py-VPB to the visualization of exogenous and endogenous H2O2 in living cells.Cell imaging study also showed that our probe was localized in the mitochondria.We envision that the probe can provide a useful tool for unmasking the biological roles of mitochondrial H2O2 in living systems.
文摘We consider semiconductor heterostructures in nanometric quantum wells, which as a consequence of the growth process display at the rugged interfaces fractal characteristics, and largely influence optical and transport properties of the carriers system. The photoluminescence and excited photoluminescence spectra in such fractal conditions are theoretically analyzed, obtaining good agreement with the experimental results. The Stokes shift and linewidth are strongly dependent on the nonequilibrium thermomechanical-statistical state of the system. The Stokes shift has its origin in the presence of a gain region in the absorption spectrum, only present when the carriers system is in a statistical degenerate state.
文摘近年来,数值波浪水槽在海洋工程研究中发挥着越来越为重要的作用,成为了水波动力学研究的焦点之一。为此,基于Navier-Stokes(N-S)方程组,首先完成了二维数值波浪水槽的构建。对于N-S方程,采用FVM(Finite Volume Method)法进行离散求解;在入口边界处,模拟活塞推板运动产生了入射波;同时,利用VOF(Volume of Fluid)法对波浪自由面进行了捕捉;在数值波浪水槽尾部,通过设置人工阻尼区实现了消波。利用该二维数值波浪水槽,对典型非线性二阶Stokes波进行了仿真模拟,通过设置虚拟波高监测仪,获取了非线性二阶Stokes波发生、发展和消亡的全过程。对比校验表明,所有仿真结果均与理论精确解相吻合。
基金supported by the National Natural Science Foundation of China (Grant No. 41105046)the National Basic Research Program of China (Grant No. 2010CB950403)the Chinese Academy of Sciences (Grant No. XDA05090000)
文摘This study identifies a decadal shift of summer surface air temperature （SAT） over Northeast Asia,including southeastern parts of Russia,Mongolia and northern China,around the mid-1990s.The results suggest that the SAT over the Northeast Asia experienced a significant warming after 1994 relative to that before 1993.This decadal shift also extends to northern China,and leads to a warmer summer over Northeast China and North China after the mid-1990s.The decadal warming over Northeast Asia is found to concur with the enhancement of South China rainfall around the mid-1990s.On the one hand,both the Northeast Asian SAT and South China rainfall exhibit this mid-1990s decadal shift only in summer,but not in other seasons.On the other hand,both the Northeast Asian SAT and South China rainfall exhibit this mid-1990s decadal shift not only in the summer seasonal mean,but also in each month of summer （June,July and August）.Furthermore,the decadal warming is found to result from an anticyclonic anomaly over Northeast Asia,which can be interpreted as the response to the increased precipitation over South China,according to previous numerical results.Thus,we conclude that the warming shift of summer Northeast Asian SAT around the mid-1990s was a remote response to the increased precipitation over South China.
基金supported in part by the New York State Office of People with Developmental Disabilities(OPWDD)Zenith Award ZEN-12-241233 from Alzheimer’s Associationa research grant#20121203 from Alzheimer’s Drug Discovery Foundation,New York
文摘Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous social and economic burden to the affected in- dividuals and their families, but is also a great scientific challenge. Currently 25-35 million people worldwide suffer from AD, the single largest cause of dementia in middle- to old-aged individuals. These numbers are projected to triple by 2050 if no treatment to prevent or reverse AD is developed.
文摘Introduction：Alzheimer’s disease（AD）begins to develop decades prior to its clinical manifestation（Sperling et al.,2011）,and while it is the most common form of dementia,as of yet there is no cure.Two of the most researched pathological features contributing to disease development are the extracellular amyloid plaques composed of amyloid-beta proteins（Aβ）and neurofibrillary tangles of tau proteins.Another feature of AD is the progression of early neuronal excitability/hyperactivity to silencing/hypoactivity（Palop and Mucke,2010）,
