Foliar resorption is a principal nutrient conservation mechanism in terrestrial vegetation that could be sensitive to ongoing changes in climate and atmospheric nitrogen(N)deposition.We quantified N resorption in nort...Foliar resorption is a principal nutrient conservation mechanism in terrestrial vegetation that could be sensitive to ongoing changes in climate and atmospheric nitrogen(N)deposition.We quantified N resorption in northern hardwood forests along an elevation gradient of decreasing temperature and increasing soil N availability to evaluate how this critical nutrient cycling process can be expected to respond to global and regional environmental changes.Foliar N resorption proficiency(NRP)increased significantly at lower elevations for both sugar maple and American beech,the dominant species in these forests.Foliar N resorption efficiency(NRE)also decreased with increasing elevation,but only in one year.Both species exhibited strong negative relationships between NRP and soil N availability.Thus,we anticipate that with climate warming and decreasing N inputs,northern hardwood forests can be expected to exhibit stronger N conservation via foliar resorption.Both species also exhibited strong correlations between resorption efficiency of N and C,but resorption of both elements was much greater for beech than sugar maple,suggesting contrasting mechanisms of nutrient conservation between these two widespread species.展开更多
Developing efficient and durable alkaline hydrogen evolution reaction(HER)catalysts is crucial for realizing high-performance,practical anion exchange membrane water electrolyzer(AEMWE)operating at ampere-level curren...Developing efficient and durable alkaline hydrogen evolution reaction(HER)catalysts is crucial for realizing high-performance,practical anion exchange membrane water electrolyzer(AEMWE)operating at ampere-level current densities.Although atomically dispersed Platinum(Pt)catalysts offer significant potential for enhancing atom utilization,their HER performance and durability are limited by the inflexibility in valence electron transfer between Pt and the support.In this study,we utilize asymmetrically single-atom copper(Cu)with tunable valence states as a valence electron reservoir(VER)to dynamically regulate the Pt 5d valence states,achieving efficient alkaline HER.In situ synchrotron radiation and theoretical calculations demonstrate that the dynamic evolution of the Pt 5d valence electron configuration optimizes the adsorption strengths of reaction intermediates.Meanwhile,single-atom Cu accelerates the rate-limiting water dissociation,and Pt facilitates subsequent^(*)H coupling.The catalyst requires only 23.5 and 177.2 mV overpotentials to achieve current densities of 10 and 500 mA cm^(-2)in 1 M KOH.Notably,the PtCu/NC exhibits a~57%lower hydrogen evolution barrier than Pt/NC.Moreover,the PtCu/NC-based AEMWE operates for over 600 h at an industrially relevant current density of 500 mA cm^(-2).展开更多
Low temperature sintering NiCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960 ℃). The NiCuZn ferrite sintered body with high-strength and high-frequency magnetic properties was fabri...Low temperature sintering NiCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960 ℃). The NiCuZn ferrite sintered body with high-strength and high-frequency magnetic properties was fabricated. Firstly, NiCuZn ferrite powder was synthesized under CO2 atmosphere at 500 ℃ from the mixed doxalate synthesized by liquid phase precipitation method. Then a small amount of boric acid (H3BO3) was added to the powder, and the NiCuZn ferrite powder compact was prepared with Newton press and CIP methods. Finally, NiCuZn ferrite sintered body was fabricated by sintering at 900 ℃ under CO2 atmosphere. The minimum sintering temperature (800 ℃) was determined by the study of high temperature shrinkage. By this method, NiCuZn ferrite sintered body with 0.5% (mass fraction) boric acid was obtained, which has the bending strength of 340 MPa. The effect of various Mn addition on electromagnetic properties were studied.展开更多
AIM:To investigate the possible biological outcome and effect of glutamine depletion in neonatal mice and rodent intestinal epithelial cells.METHODS:We developed three kinds of artificial milk with different amounts o...AIM:To investigate the possible biological outcome and effect of glutamine depletion in neonatal mice and rodent intestinal epithelial cells.METHODS:We developed three kinds of artificial milk with different amounts of glutamine;Complete amino acid milk (CAM),which is based on maternal mouse milk,glutamine-depleted milk (GDM),and glutaminerich milk (GRM).GRM contains three-fold more glutamine than CAM.Eighty-seven newborn mice were divided into three groups and were fed with either of CAM,GDM,or GRM via a recently improved nipple-bottle system for seven days.After the feeding period,the mice were subjected to macroscopic and microscopic observations by immunohistochemistry for 5-bromo-2'deoxyuridine (BrdU) and Ki-67 as markers of cell proliferation,and for cleaved-caspase-3 as a marker of apoptosis.Moreover,IEC6 rat intestinal epithelial cells were cultured in different concentrations of glutamine and were subject to a 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)2H-5-tetrazolio]-1,3-benzene disulfonate cell proliferation assay,flow cytometry,and western blotting to examine the biological effect of glutamine on cell growth and apoptosis.RESULTS:During the feeding period,we found colonic hemorrhage in six of 28 GDM-fed mice (21.4%),but not in the GRM-fed mice,with no differences in body weight gain between each group.Microscopic examination showed destruction of microvilli and the disappearance of glycocalyx of the intestinal wall in the colon epithelial tissues taken from GDM-fed mice.Intake of GDM reduced BrdU incorporation (the average percentage of BrdU-positive staining;GRM:13.8%,CAM:10.7%,GDM:1.14%,GRM vs GDM:P < 0.001,CAM vs GDM:P < 0.001) and Ki-67 labeling index (the average percentage of Ki67-positive staining;GRM:24.5%,CAM:22.4% GDM:19.4%,GRM vs GDM:P=0.001,CAM vs GDM:P =0.049),suggesting that glutamine depletion inhibited cell proliferation of intestinal epithelial cells.Glutamine deprivation further caused the deformation of the nuclear membrane and the plasma membrane,accompanied by chromatin degeneration and an absence of fat droplets from the colonic epithelia,indicating that the cells underwent apoptosis.Moreover,immunohistochemical analysis revealed the appearance of cleaved caspase-3 in colonic epithelial cells of GDM-fed mice.Finally,when IEC6 rat intestinal epithelial cells were cultured without glutamine,cell proliferation was significantly suppressed after 24 h (relative cell growth;4 mmol/L:100.0% ± 36.1%,0 mmol/L:25.3% ± 25.0%,P < 0.05),with severe cellular damage.The cells underwent apoptosis,accompanied by increased cell population in sub-G0 phase (4 mmol/L:1.68%,0.4 mmol/L:1.35%,0 mmol/L:5.21%),where dying cells are supposed to accumulate.CONCLUSION:Glutamine is an important alimentary component for the maintenance of intestinal mucosa.Glutamine deprivation can cause instability of the intestinal epithelial alignment by increased apoptosis.展开更多
In the framework of the Thomas-Fermi approximation,we systematically study the EOSs and microscopic structures of neutron star matter in a vast density range with n_(b)≈10^(-10)-2 fm^(-3),where various covariant dens...In the framework of the Thomas-Fermi approximation,we systematically study the EOSs and microscopic structures of neutron star matter in a vast density range with n_(b)≈10^(-10)-2 fm^(-3),where various covariant density functionals are adopted,i.e.,those with nonlinear self couplings(NL3,PK1,TM1,GM1,MTVTC)and density-dependent couplings(DD-LZ1,DDME-X,PKDD,DDME2,DD2,TW99).It is found that the EOSs generally coincide with each other at nb■10^(-4)fm^(-3)and 0.1 fm^(-3)■n_(b)■0.3 fm^(-3),while in other density regions they are sensitive to the effective interactions between nucleons.By adopting functionals with a larger slope of symmetry energy L,the curvature parameter K_(sym)and neutron drip density generally increases,while the droplet size,proton number of nucleus,core-crust transition density,and onset density of non-spherical nuclei,decrease.All functionals predict neutron stars with maximum masses exceeding the two-solar-mass limit,while those of DD2,DD-LZ1,DD-ME2,and DDME-X predict optimum neutron star radii according to the observational constraints.Nevertheless,the corresponding skewness coefficients J are much larger than expected,while only the functionals MTVTC and TW99 meet the start-of-art constraints on J.More accurate measurements on the radius of PSR J0740+6620 and the maximum mass of neutron stars are thus essential to identify the functional that satisfies all constraints from nuclear physics and astrophysical observations.Approximate linear correlations between neutron stars’radii at M=1.4M⊙and 2M⊙,the slope L and curvature parameter K_(sym)of symmetry energy are observed as well,which are mainly attributed to the curvature-slope correlations in the functionals adopted here.The results presented here are applicable for investigations of the structures and evolutions of compact stars in a unified manner.展开更多
ZnO films grown on sapphire substrates are implanted with lO0-keV Li ions up to a total dose of 1 × 10^16 cm^-2. Vacancy-type defects, mostly vacancy dusters, are observed by positron annihilation measurements af...ZnO films grown on sapphire substrates are implanted with lO0-keV Li ions up to a total dose of 1 × 10^16 cm^-2. Vacancy-type defects, mostly vacancy dusters, are observed by positron annihilation measurements after implantation. Upon annealing, they first have an agglomeration process which leads to the growth in the vacancy size. After anneling at about 500℃, vacancy clusters grow into microvoids, which is indicated by the positronium formation. With annealing temperature increases to above 500℃, the microvoids begin to recover, and finMly M1 the implantation-induced vacancy defects are removed at 1000℃. No Li nanoclusters can be observed after Li^＋ implantation.展开更多
The void evolution inα-Al2O3 irradiated by En≥1 MeV neutrons of 3×10^(20)cm^(-2) and post-annealed from 100°C to 1050°C has been studied by a positron annihilation lifetime technique.The void nucleati...The void evolution inα-Al2O3 irradiated by En≥1 MeV neutrons of 3×10^(20)cm^(-2) and post-annealed from 100°C to 1050°C has been studied by a positron annihilation lifetime technique.The void nucleation starts at 500°C.In the annealing temperature region from 550℃ to 750℃,the radius of created voids keeps constant at a value of about 0.29 nm and the number of voids increases with increasing temperature.Afterwards,the radius of voids increases rapidly with the increasing annealing temperature and reaches 1.21nm at 1050℃.展开更多
Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water.In this paper,the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluores...Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water.In this paper,the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluorescens was studied.Concomitant accumulation of divalent cations of Mg2+,Zn2+,and Co2+during precipitation of Mn oxides was also studied.The time course of the Mn concentration in solution showed an abrupt decrease after contact of Mn(VII)with microbial cells,followed by an increase after^24 hr.XRD analysis of the precipitated Mn oxides,called biomass Mn oxides,showed the formation of low-crystalline birnessite.Visible spectroscopy and X-ray absorption near edge structure(XANES)analyses indicated that dissolved Mn(VII)was reduced to form biomass Mn oxides involving Mn(IV)and Mn(III),followed by reduction to soluble Mn(II).The numbers of electron transferred from microbial cells to permanganate and to biomass Mn oxides for 24 hr after the contact indicated that the numbers of electron transfer from microbial cell was approximately 50 times higher to dissolved permanganate than to the biomass Mn oxides in present experimental conditions.The 24 hr accumulation of divalent cations during formation of biomass Mn oxides was in the order of Co2+>Zn2+>Mg2+.XANES analysis of Co showed that oxidation of Co2+to Co3+resulted in higher accumulation of Co than Zn and Mg.Thus,treatment of surface water by KMnO4 solution is effective not only for disinfection of microorganisms,but also for the elimination of metal cations from surface water.展开更多
Atomic and electronic structures of adsorbed nickel and vanadium atoms and nanoclusters （Nin and Vn, n = 1-10） on hexagonal h-BN and BC3 lattices were studied using DFT PBE/PBC/PW （Perdew-Burke- Ernzerhof potential...Atomic and electronic structures of adsorbed nickel and vanadium atoms and nanoclusters （Nin and Vn, n = 1-10） on hexagonal h-BN and BC3 lattices were studied using DFT PBE/PBC/PW （Perdew-Burke- Ernzerhof potential of density functional theory/periodic boundary conditions/plane wave basis set） technique. For the sake of comparison the structure and properties of the same nanoclusters deposited on pristine graphene were calculated as well. It was found that for all types of supports an increase of n from 1 to 10 leaded to decrease of coordination types from 776 to r/2 and 771. The h-BN- and BC3-based nanocomposites were characterized by high （up to 18 μ for Ni10/BC3） magnetic moments of the nanoclusters and featured by positive binding energies. The graphene-based nanocomposites revealed energetic stability and, in general, lower magnetic moments per unit cell. The direct potential energy barriers for migration of Ni η2/η21 and η6/η6 types of dimers on graphene were low （10.9-28.9 kJ/mol） with high reverse barriers for η6/η6 dimers, which favored dynamically equilibrated Ni clusterization on graphene.展开更多
In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalizat...In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalization of the f-p model, we compare the eigen-energies in the first Brillouin zone with the results of relativistic band-structure calculations. Here we emphasize a key role of f-p hybridization in order to understand the electronic structure of actinide dioxides. In particular, it is found that the position of energy levels of Г7 and Г8 states determined from crystalline electric field (CEF) potentials depends on the f-p hybridization. We investiagte the values of the Slater-Koster integrals for f-p hybridization, (fpσ) and (fpπ), which reproduce simultaneously the local CEF states and the band-structure calculation results. Then, we find that the absolute value of (fpπ) should be small in comparison with (fpσ) = 1 eV. The small value of |(fpπ)| is consistent with the condition to obtain the octupole ordering in the previous analysis of the f-p model.展开更多
Machine learning is becoming a valuable tool for scientific discovery.Particularly attractive is the application of machine learning methods to the field of materials development,which enables innovations by discoveri...Machine learning is becoming a valuable tool for scientific discovery.Particularly attractive is the application of machine learning methods to the field of materials development,which enables innovations by discovering new and better functional materials.To apply machine learning to actual materials development,close collaboration between scientists and machine learning tools is necessary.However,such collaboration has been so far impeded by the black box nature of many machine learning algorithms.It is often difficult for scientists to interpret the data-driven models from the viewpoint of material science and physics.Here,we demonstrate the development of spin-driven thermoelectric materials with anomalous Nernst effect by using an interpretable machine learning method called factorized asymptotic Bayesian inference hierarchical mixture of experts(FAB/HMEs).Based on prior knowledge of material science and physics,we were able to extract from the interpretable machine learning some surprising correlations and new knowledge about spin-driven thermoelectric materials.Guided by this,we carried out an actual material synthesis that led to the identification of a novel spin-driven thermoelectric material.This material shows the largest thermopower to date.展开更多
The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ...The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ simulations with varied protocols to evaluate the effectiveness of different descriptors in predicting mechanical properties across both low-and high-pressure regimes.Our findings demonstrate that conventional structural and configurational descriptors fail to correlate with the mechanical response following pressure release,whereas the activation energy descriptor exhibits robust linearity with shear modulus after correcting for pressure effects.Notably,the soft mode parameter emerges as an ideal and computationally efficient alternative for capturing this mechanical behavior.These findings provide critical insights into the influence of pressure on glassy properties,integrating the distinct features of compressed glasses into a unified theoretical framework.展开更多
On approaching the glass transition,the structural relaxation of glass-forming liquids slows down drastically,along with a significant growth of dynamic heterogeneity.Recent studies have achieved substantial advanceme...On approaching the glass transition,the structural relaxation of glass-forming liquids slows down drastically,along with a significant growth of dynamic heterogeneity.Recent studies have achieved substantial advancements in elucidating the quantitative correlations between structural relaxation and dynamic heterogeneity.Here,we present the discovery of a novel dynamic crossover with possibly universal dynamic signatures by investigating the relationship between structural relaxation and dynamic heterogeneity.Specifically,the structural relaxation time at the dynamic crossoverτ_(c)is equal to the time scale for the maximum non-Gaussian parameter,which could serve as a quantitative characterization of dynamic heterogeneity.The degree of dynamic heterogeneity at the crossover is approximately equivalent across all investigated glass-forming liquids,leading to a scaling collapse between structural relaxation and dynamic heterogeneity.Moreover,the mean squared displacement at the structural relaxation time is nearly constant across different temperatures as long as the structural relaxation time does not exceedτ_(c).We further observe that the temperature at the dynamic crossover is lower than the onset temperature of slow dynamics.Our findings thus suggest the existence of a novel dynamic crossover with possibly universal dynamic signatures in glass-forming liquids,which merits in-depth investigations.展开更多
In the past two decades,metamaterials and metasurfaces[1,2]have been providing a new playground for light manipulation,establishing concepts and experimental platforms that enable structuring light in compact footprin...In the past two decades,metamaterials and metasurfaces[1,2]have been providing a new playground for light manipulation,establishing concepts and experimental platforms that enable structuring light in compact footprints with exceptional benefits for a wide range of technologies.Metasurfaces,in particular,have been developing a paradigm of compactification of optical components,enabling manipulation of the optical wavefront within subwavelength footprints and unprecedented control over all properties of light,from spectrum to polarization,from wavefront shaping to spatial and temporal coherence[3].The progress in the past few years has been truly impressive,bringing many of these concepts from proof-of-concept ideas to practical demonstrations ready for commercialization and deployment.As such,it has become imperative to explore ways to integrate metamaterial and metasurface devices into photonic platforms and enable platforms compatible with existing photonic circuits and systems.展开更多
The terahertz(THz)frequency range,situated between microwave and infrared radiation,has emerged as a pivotal domain with broad applications in high-speed communication,imaging,sensing,and biosensing.The development of...The terahertz(THz)frequency range,situated between microwave and infrared radiation,has emerged as a pivotal domain with broad applications in high-speed communication,imaging,sensing,and biosensing.The development of topological THz metadevices represents a notable advancement for photonic technologies,leveraging the distinctive electronic properties and quantum-inspired phenomena inherent to topological materials.These devices enable robust waveguiding capabilities,positioning them as critical components for on-chip data transfer and photonic integrated circuits,particularly within emerging 6G communication frameworks.A principal advantage resides in the capacity to maintain low-loss wave propagation while effectively suppressing backscattering phenomena,a critical requirement for functional components operating at higher frequencies.In parallel,by leveraging advanced materials such as liquid crystals,plasma,and phase-change materials,these devices facilitate real-time control over essential wave parameters,including amplitude,frequency,and phase,which augments the functionality of both communication and sensing systems,opening new avenues for THz-based technologies.This review outlines fundamental principles of topological components and reconfigurable metadevices operating at THz frequencies.We further explore emerging strategies that integrate topological properties and reconfigurability,with a specific focus on their implementation in chip-scale photonic circuits and free-space wavefront control.展开更多
The next generation of smart imaging and vision systems will require compact and tunable optical computing hardware to perform high-speed and low-power image processing.These requirements are driving the development o...The next generation of smart imaging and vision systems will require compact and tunable optical computing hardware to perform high-speed and low-power image processing.These requirements are driving the development of computing metasurfaces to realize efficient front-end analog optical pre-processors,especially for edge detection capability.Yet,there is still a lack of reconfigurable or programmable schemes,which may drastically enhance the impact of these devices at the system level.Here,we propose and experimentally demonstrate a reconfigurable flat optical image processor using low-loss phase-change nonlocal metasurfaces.The metasurface is configured to realize different transfer functions in spatial frequency space,when transitioning the phase-change material between its amorphous and crystalline phases.This enables edge detection and bright field imaging modes on the same device.The metasurface is compatible with a large numerical aperture of~0.5,making it suitable for high resolution coherent optical imaging microscopy.The concept of phase-change reconfigurable nonlocal metasurfaces may enable emerging applications of artificial intelligence-assisted imaging and vision devices with switchable multitasking.展开更多
基金National Science Foundation supported this research through the Long Term Ecological Research(LTER)Grant to Hubbard Brook(NSF DEB1114804,1637685,and 2224545)by the project grant(NSF DEB,2020397).
文摘Foliar resorption is a principal nutrient conservation mechanism in terrestrial vegetation that could be sensitive to ongoing changes in climate and atmospheric nitrogen(N)deposition.We quantified N resorption in northern hardwood forests along an elevation gradient of decreasing temperature and increasing soil N availability to evaluate how this critical nutrient cycling process can be expected to respond to global and regional environmental changes.Foliar N resorption proficiency(NRP)increased significantly at lower elevations for both sugar maple and American beech,the dominant species in these forests.Foliar N resorption efficiency(NRE)also decreased with increasing elevation,but only in one year.Both species exhibited strong negative relationships between NRP and soil N availability.Thus,we anticipate that with climate warming and decreasing N inputs,northern hardwood forests can be expected to exhibit stronger N conservation via foliar resorption.Both species also exhibited strong correlations between resorption efficiency of N and C,but resorption of both elements was much greater for beech than sugar maple,suggesting contrasting mechanisms of nutrient conservation between these two widespread species.
基金supported by the Ningbo Top-Talent Team Program,Program for the National Natural Science Foundation of China(22106166)the Yongjiang Innovative Individual Introduction of China,and the China Postdoctoral Science Foundation(2022M723253)。
文摘Developing efficient and durable alkaline hydrogen evolution reaction(HER)catalysts is crucial for realizing high-performance,practical anion exchange membrane water electrolyzer(AEMWE)operating at ampere-level current densities.Although atomically dispersed Platinum(Pt)catalysts offer significant potential for enhancing atom utilization,their HER performance and durability are limited by the inflexibility in valence electron transfer between Pt and the support.In this study,we utilize asymmetrically single-atom copper(Cu)with tunable valence states as a valence electron reservoir(VER)to dynamically regulate the Pt 5d valence states,achieving efficient alkaline HER.In situ synchrotron radiation and theoretical calculations demonstrate that the dynamic evolution of the Pt 5d valence electron configuration optimizes the adsorption strengths of reaction intermediates.Meanwhile,single-atom Cu accelerates the rate-limiting water dissociation,and Pt facilitates subsequent^(*)H coupling.The catalyst requires only 23.5 and 177.2 mV overpotentials to achieve current densities of 10 and 500 mA cm^(-2)in 1 M KOH.Notably,the PtCu/NC exhibits a~57%lower hydrogen evolution barrier than Pt/NC.Moreover,the PtCu/NC-based AEMWE operates for over 600 h at an industrially relevant current density of 500 mA cm^(-2).
文摘Low temperature sintering NiCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960 ℃). The NiCuZn ferrite sintered body with high-strength and high-frequency magnetic properties was fabricated. Firstly, NiCuZn ferrite powder was synthesized under CO2 atmosphere at 500 ℃ from the mixed doxalate synthesized by liquid phase precipitation method. Then a small amount of boric acid (H3BO3) was added to the powder, and the NiCuZn ferrite powder compact was prepared with Newton press and CIP methods. Finally, NiCuZn ferrite sintered body was fabricated by sintering at 900 ℃ under CO2 atmosphere. The minimum sintering temperature (800 ℃) was determined by the study of high temperature shrinkage. By this method, NiCuZn ferrite sintered body with 0.5% (mass fraction) boric acid was obtained, which has the bending strength of 340 MPa. The effect of various Mn addition on electromagnetic properties were studied.
基金Supported by The trust accounts of the Department of Gastroenterological Surgery,Transplant,and Surgical Oncology,Graduate School of Medicine,Dentistry,and Pharmaceutical Sciences,Okayama University
文摘AIM:To investigate the possible biological outcome and effect of glutamine depletion in neonatal mice and rodent intestinal epithelial cells.METHODS:We developed three kinds of artificial milk with different amounts of glutamine;Complete amino acid milk (CAM),which is based on maternal mouse milk,glutamine-depleted milk (GDM),and glutaminerich milk (GRM).GRM contains three-fold more glutamine than CAM.Eighty-seven newborn mice were divided into three groups and were fed with either of CAM,GDM,or GRM via a recently improved nipple-bottle system for seven days.After the feeding period,the mice were subjected to macroscopic and microscopic observations by immunohistochemistry for 5-bromo-2'deoxyuridine (BrdU) and Ki-67 as markers of cell proliferation,and for cleaved-caspase-3 as a marker of apoptosis.Moreover,IEC6 rat intestinal epithelial cells were cultured in different concentrations of glutamine and were subject to a 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)2H-5-tetrazolio]-1,3-benzene disulfonate cell proliferation assay,flow cytometry,and western blotting to examine the biological effect of glutamine on cell growth and apoptosis.RESULTS:During the feeding period,we found colonic hemorrhage in six of 28 GDM-fed mice (21.4%),but not in the GRM-fed mice,with no differences in body weight gain between each group.Microscopic examination showed destruction of microvilli and the disappearance of glycocalyx of the intestinal wall in the colon epithelial tissues taken from GDM-fed mice.Intake of GDM reduced BrdU incorporation (the average percentage of BrdU-positive staining;GRM:13.8%,CAM:10.7%,GDM:1.14%,GRM vs GDM:P < 0.001,CAM vs GDM:P < 0.001) and Ki-67 labeling index (the average percentage of Ki67-positive staining;GRM:24.5%,CAM:22.4% GDM:19.4%,GRM vs GDM:P=0.001,CAM vs GDM:P =0.049),suggesting that glutamine depletion inhibited cell proliferation of intestinal epithelial cells.Glutamine deprivation further caused the deformation of the nuclear membrane and the plasma membrane,accompanied by chromatin degeneration and an absence of fat droplets from the colonic epithelia,indicating that the cells underwent apoptosis.Moreover,immunohistochemical analysis revealed the appearance of cleaved caspase-3 in colonic epithelial cells of GDM-fed mice.Finally,when IEC6 rat intestinal epithelial cells were cultured without glutamine,cell proliferation was significantly suppressed after 24 h (relative cell growth;4 mmol/L:100.0% ± 36.1%,0 mmol/L:25.3% ± 25.0%,P < 0.05),with severe cellular damage.The cells underwent apoptosis,accompanied by increased cell population in sub-G0 phase (4 mmol/L:1.68%,0.4 mmol/L:1.35%,0 mmol/L:5.21%),where dying cells are supposed to accumulate.CONCLUSION:Glutamine is an important alimentary component for the maintenance of intestinal mucosa.Glutamine deprivation can cause instability of the intestinal epithelial alignment by increased apoptosis.
基金supported by National SKA Program of China No.2020SKA0120300National Natural Science Foundation of China(Grant No.11875052,No.11873040,No.11705163,and No.11525524)+3 种基金the science research grants from the China Manned Space Project(No.CMS-CSST-2021-B11)the Youth Innovation Fund of Xiamen(No.3502Z20206061)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2021-sp36)the National Key R&D Program of China No.2018YFA0404402
文摘In the framework of the Thomas-Fermi approximation,we systematically study the EOSs and microscopic structures of neutron star matter in a vast density range with n_(b)≈10^(-10)-2 fm^(-3),where various covariant density functionals are adopted,i.e.,those with nonlinear self couplings(NL3,PK1,TM1,GM1,MTVTC)and density-dependent couplings(DD-LZ1,DDME-X,PKDD,DDME2,DD2,TW99).It is found that the EOSs generally coincide with each other at nb■10^(-4)fm^(-3)and 0.1 fm^(-3)■n_(b)■0.3 fm^(-3),while in other density regions they are sensitive to the effective interactions between nucleons.By adopting functionals with a larger slope of symmetry energy L,the curvature parameter K_(sym)and neutron drip density generally increases,while the droplet size,proton number of nucleus,core-crust transition density,and onset density of non-spherical nuclei,decrease.All functionals predict neutron stars with maximum masses exceeding the two-solar-mass limit,while those of DD2,DD-LZ1,DD-ME2,and DDME-X predict optimum neutron star radii according to the observational constraints.Nevertheless,the corresponding skewness coefficients J are much larger than expected,while only the functionals MTVTC and TW99 meet the start-of-art constraints on J.More accurate measurements on the radius of PSR J0740+6620 and the maximum mass of neutron stars are thus essential to identify the functional that satisfies all constraints from nuclear physics and astrophysical observations.Approximate linear correlations between neutron stars’radii at M=1.4M⊙and 2M⊙,the slope L and curvature parameter K_(sym)of symmetry energy are observed as well,which are mainly attributed to the curvature-slope correlations in the functionals adopted here.The results presented here are applicable for investigations of the structures and evolutions of compact stars in a unified manner.
文摘ZnO films grown on sapphire substrates are implanted with lO0-keV Li ions up to a total dose of 1 × 10^16 cm^-2. Vacancy-type defects, mostly vacancy dusters, are observed by positron annihilation measurements after implantation. Upon annealing, they first have an agglomeration process which leads to the growth in the vacancy size. After anneling at about 500℃, vacancy clusters grow into microvoids, which is indicated by the positronium formation. With annealing temperature increases to above 500℃, the microvoids begin to recover, and finMly M1 the implantation-induced vacancy defects are removed at 1000℃. No Li nanoclusters can be observed after Li^＋ implantation.
基金Supported in par t by the National Natural Science Foundation of China under Grant No.19835050the Nuclear Indus try Science Foundation of China under Grant No.H7196BO116the Contract of 97J11.2.8HZ010.
文摘The void evolution inα-Al2O3 irradiated by En≥1 MeV neutrons of 3×10^(20)cm^(-2) and post-annealed from 100°C to 1050°C has been studied by a positron annihilation lifetime technique.The void nucleation starts at 500°C.In the annealing temperature region from 550℃ to 750℃,the radius of created voids keeps constant at a value of about 0.29 nm and the number of voids increases with increasing temperature.Afterwards,the radius of voids increases rapidly with the increasing annealing temperature and reaches 1.21nm at 1050℃.
基金Financial support was provided to TO by the Japan Society for the Promotion of Science (JSPS Grant-in-Aid for Scientific Research No. 17K19086)performed with the approval of the Photon Factory, KEK (Proposal NO. 2012G179)
文摘Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water.In this paper,the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluorescens was studied.Concomitant accumulation of divalent cations of Mg2+,Zn2+,and Co2+during precipitation of Mn oxides was also studied.The time course of the Mn concentration in solution showed an abrupt decrease after contact of Mn(VII)with microbial cells,followed by an increase after^24 hr.XRD analysis of the precipitated Mn oxides,called biomass Mn oxides,showed the formation of low-crystalline birnessite.Visible spectroscopy and X-ray absorption near edge structure(XANES)analyses indicated that dissolved Mn(VII)was reduced to form biomass Mn oxides involving Mn(IV)and Mn(III),followed by reduction to soluble Mn(II).The numbers of electron transferred from microbial cells to permanganate and to biomass Mn oxides for 24 hr after the contact indicated that the numbers of electron transfer from microbial cell was approximately 50 times higher to dissolved permanganate than to the biomass Mn oxides in present experimental conditions.The 24 hr accumulation of divalent cations during formation of biomass Mn oxides was in the order of Co2+>Zn2+>Mg2+.XANES analysis of Co showed that oxidation of Co2+to Co3+resulted in higher accumulation of Co than Zn and Mg.Thus,treatment of surface water by KMnO4 solution is effective not only for disinfection of microorganisms,but also for the elimination of metal cations from surface water.
基金supported by Russian Scientific Foundation (Grant No. 14-13-00139)
文摘Atomic and electronic structures of adsorbed nickel and vanadium atoms and nanoclusters （Nin and Vn, n = 1-10） on hexagonal h-BN and BC3 lattices were studied using DFT PBE/PBC/PW （Perdew-Burke- Ernzerhof potential of density functional theory/periodic boundary conditions/plane wave basis set） technique. For the sake of comparison the structure and properties of the same nanoclusters deposited on pristine graphene were calculated as well. It was found that for all types of supports an increase of n from 1 to 10 leaded to decrease of coordination types from 776 to r/2 and 771. The h-BN- and BC3-based nanocomposites were characterized by high （up to 18 μ for Ni10/BC3） magnetic moments of the nanoclusters and featured by positive binding energies. The graphene-based nanocomposites revealed energetic stability and, in general, lower magnetic moments per unit cell. The direct potential energy barriers for migration of Ni η2/η21 and η6/η6 types of dimers on graphene were low （10.9-28.9 kJ/mol） with high reverse barriers for η6/η6 dimers, which favored dynamically equilibrated Ni clusterization on graphene.
文摘In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalization of the f-p model, we compare the eigen-energies in the first Brillouin zone with the results of relativistic band-structure calculations. Here we emphasize a key role of f-p hybridization in order to understand the electronic structure of actinide dioxides. In particular, it is found that the position of energy levels of Г7 and Г8 states determined from crystalline electric field (CEF) potentials depends on the f-p hybridization. We investiagte the values of the Slater-Koster integrals for f-p hybridization, (fpσ) and (fpπ), which reproduce simultaneously the local CEF states and the band-structure calculation results. Then, we find that the absolute value of (fpπ) should be small in comparison with (fpσ) = 1 eV. The small value of |(fpπ)| is consistent with the condition to obtain the octupole ordering in the previous analysis of the f-p model.
基金This work was supported by JST-PRESTO“Advanced Materials Informatics through Comprehensive Integration among Theoretical,Experimental,Computational and Data-Centric Sciences”(Grant No.JPMJPR17N4)JST-ERATO“Spin Quantum Rectification Project”(Grant No.JPMJER1402)I.T.is supported in part by C-SPIN,one of six centers of STARnet,a Semiconductor Research Corporation program,sponsored by MARCO and DARPA.
文摘Machine learning is becoming a valuable tool for scientific discovery.Particularly attractive is the application of machine learning methods to the field of materials development,which enables innovations by discovering new and better functional materials.To apply machine learning to actual materials development,close collaboration between scientists and machine learning tools is necessary.However,such collaboration has been so far impeded by the black box nature of many machine learning algorithms.It is often difficult for scientists to interpret the data-driven models from the viewpoint of material science and physics.Here,we demonstrate the development of spin-driven thermoelectric materials with anomalous Nernst effect by using an interpretable machine learning method called factorized asymptotic Bayesian inference hierarchical mixture of experts(FAB/HMEs).Based on prior knowledge of material science and physics,we were able to extract from the interpretable machine learning some surprising correlations and new knowledge about spin-driven thermoelectric materials.Guided by this,we carried out an actual material synthesis that led to the identification of a novel spin-driven thermoelectric material.This material shows the largest thermopower to date.
基金supported by the National Natural Science Foundation of China (Grant Nos.T2325004 and 52161160330)the National Natural Science Foundation of China (Grants No.12504233)+2 种基金Advanced MaterialsNational Science and Technology Major Project (Grant No.2024ZD0606900)the Talent Hub for “AI+New Materials” Basic Researchthe Key Research and Development Program of Ningbo (Grant No.2025Z088)。
文摘The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ simulations with varied protocols to evaluate the effectiveness of different descriptors in predicting mechanical properties across both low-and high-pressure regimes.Our findings demonstrate that conventional structural and configurational descriptors fail to correlate with the mechanical response following pressure release,whereas the activation energy descriptor exhibits robust linearity with shear modulus after correcting for pressure effects.Notably,the soft mode parameter emerges as an ideal and computationally efficient alternative for capturing this mechanical behavior.These findings provide critical insights into the influence of pressure on glassy properties,integrating the distinct features of compressed glasses into a unified theoretical framework.
基金support from the National Natural Science Foundation of China(Grant Nos.12374202 and 12004001)Anhui Projects(Grant Nos.2022AH020009,S020218016,and Z010118169),and Hefei City(Grant No.Z020132009)+3 种基金support from the National Natural Science Foundation of China(Grant Nos.T2325004 and 52161160330)Advanced Materials-National Science and Technology Major Project(Grant No.2024ZD0606900)the Talent Hub for“AI+New Materials”Basic ResearchHefei Advanced Computing Center,Beijing Super Cloud Computing Center,and the High-Performance Computing Platform of Anhui University for providing computing resources.
文摘On approaching the glass transition,the structural relaxation of glass-forming liquids slows down drastically,along with a significant growth of dynamic heterogeneity.Recent studies have achieved substantial advancements in elucidating the quantitative correlations between structural relaxation and dynamic heterogeneity.Here,we present the discovery of a novel dynamic crossover with possibly universal dynamic signatures by investigating the relationship between structural relaxation and dynamic heterogeneity.Specifically,the structural relaxation time at the dynamic crossoverτ_(c)is equal to the time scale for the maximum non-Gaussian parameter,which could serve as a quantitative characterization of dynamic heterogeneity.The degree of dynamic heterogeneity at the crossover is approximately equivalent across all investigated glass-forming liquids,leading to a scaling collapse between structural relaxation and dynamic heterogeneity.Moreover,the mean squared displacement at the structural relaxation time is nearly constant across different temperatures as long as the structural relaxation time does not exceedτ_(c).We further observe that the temperature at the dynamic crossover is lower than the onset temperature of slow dynamics.Our findings thus suggest the existence of a novel dynamic crossover with possibly universal dynamic signatures in glass-forming liquids,which merits in-depth investigations.
文摘In the past two decades,metamaterials and metasurfaces[1,2]have been providing a new playground for light manipulation,establishing concepts and experimental platforms that enable structuring light in compact footprints with exceptional benefits for a wide range of technologies.Metasurfaces,in particular,have been developing a paradigm of compactification of optical components,enabling manipulation of the optical wavefront within subwavelength footprints and unprecedented control over all properties of light,from spectrum to polarization,from wavefront shaping to spatial and temporal coherence[3].The progress in the past few years has been truly impressive,bringing many of these concepts from proof-of-concept ideas to practical demonstrations ready for commercialization and deployment.As such,it has become imperative to explore ways to integrate metamaterial and metasurface devices into photonic platforms and enable platforms compatible with existing photonic circuits and systems.
基金the Nanyang Assistant Professorship Start-up Grant and Ministry of Education(Singapore)under AcRF TIER1(RG61/23)support from the Simons Foundation and the Air Force Office of Scientific Research MURI program.
文摘The terahertz(THz)frequency range,situated between microwave and infrared radiation,has emerged as a pivotal domain with broad applications in high-speed communication,imaging,sensing,and biosensing.The development of topological THz metadevices represents a notable advancement for photonic technologies,leveraging the distinctive electronic properties and quantum-inspired phenomena inherent to topological materials.These devices enable robust waveguiding capabilities,positioning them as critical components for on-chip data transfer and photonic integrated circuits,particularly within emerging 6G communication frameworks.A principal advantage resides in the capacity to maintain low-loss wave propagation while effectively suppressing backscattering phenomena,a critical requirement for functional components operating at higher frequencies.In parallel,by leveraging advanced materials such as liquid crystals,plasma,and phase-change materials,these devices facilitate real-time control over essential wave parameters,including amplitude,frequency,and phase,which augments the functionality of both communication and sensing systems,opening new avenues for THz-based technologies.This review outlines fundamental principles of topological components and reconfigurable metadevices operating at THz frequencies.We further explore emerging strategies that integrate topological properties and reconfigurability,with a specific focus on their implementation in chip-scale photonic circuits and free-space wavefront control.
基金supported by European Union’s Horizon 2020 research and innovation program(Grant No.101017237,PHOENICS Project)European Union’s EIC Pathfinder program(Grant No.101046878,HYBRAIN Project and No.101098717 RESPITE Project)+1 种基金funded in part by the UKRI[EP/T023899/1,EP/R001677/1,EP/W003341/1 and EP/W022931/1]funding from the Marie Sklodowska-Curie Individual Fellowship 101068089(METASCALE).
文摘The next generation of smart imaging and vision systems will require compact and tunable optical computing hardware to perform high-speed and low-power image processing.These requirements are driving the development of computing metasurfaces to realize efficient front-end analog optical pre-processors,especially for edge detection capability.Yet,there is still a lack of reconfigurable or programmable schemes,which may drastically enhance the impact of these devices at the system level.Here,we propose and experimentally demonstrate a reconfigurable flat optical image processor using low-loss phase-change nonlocal metasurfaces.The metasurface is configured to realize different transfer functions in spatial frequency space,when transitioning the phase-change material between its amorphous and crystalline phases.This enables edge detection and bright field imaging modes on the same device.The metasurface is compatible with a large numerical aperture of~0.5,making it suitable for high resolution coherent optical imaging microscopy.The concept of phase-change reconfigurable nonlocal metasurfaces may enable emerging applications of artificial intelligence-assisted imaging and vision devices with switchable multitasking.
