The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake...The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of attention.In this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold boxes.Cyclic shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear rate.The results indicate that the shear stress vs.shear displacement curves under each shear cycle and the peak shear strength vs.cyclic number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with mudstone.The peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing conditions.The normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.展开更多
Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using ...Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.展开更多
Naturally occurring radium(^(223)Ra,^(224)Ra,^(226)Ra,and^(228)Ra)isotopes have been widely applied as geochemical tracers in marine environments,especially when estimating the submarine groundwater discharge(SGD).In ...Naturally occurring radium(^(223)Ra,^(224)Ra,^(226)Ra,and^(228)Ra)isotopes have been widely applied as geochemical tracers in marine environments,especially when estimating the submarine groundwater discharge(SGD).In this sense,the influencing factors and transport mechanism of radium isotope activity in aquifers can be key information for SGD estimation.This work evaluates the adsorption/desorption behavior of^(224)Ra and^(226)Ra in the solid-liquid phase through a leaching experiment and analysis of field data.The results suggested that radium isotope activity was positively correlated with salinity and grain size,in the case of abundant sediments.Through ion analysis,we found that the ions(Na^(+),Ca^(2+),Mg^(2+),and Ba^(2+))exchanged with radium isotopes in the process of transport.A 1-D reactive transport model was established to simulate the transport process of radium isotope in aquifers.The model successfully simulated the variation of radium isotope desorption activity with salinity and was subsequently verified in the field.This study contributes to the understanding of the geochemical behavior of radium isotopes in aquifers and provides guidance for selecting a suitable groundwater endmember in SGD estimation.展开更多
The existing graph convolution methods usually suffer high computational burdens,large memory requirements,and intractable batch-processing.In this paper,we propose a high-efficient variational gridded graph convoluti...The existing graph convolution methods usually suffer high computational burdens,large memory requirements,and intractable batch-processing.In this paper,we propose a high-efficient variational gridded graph convolution network(VG-GCN)to encode non-regular graph data,which overcomes all these aforementioned problems.To capture graph topology structures efficiently,in the proposed framework,we propose a hierarchically-coarsened random walk(hcr-walk)by taking advantage of the classic random walk and node/edge encapsulation.The hcr-walk greatly mitigates the problem of exponentially explosive sampling times which occur in the classic version,while preserving graph structures well.To efficiently encode local hcr-walk around one reference node,we project hcrwalk into an ordered space to form image-like grid data,which favors those conventional convolution networks.Instead of the direct 2-D convolution filtering,a variational convolution block(VCB)is designed to model the distribution of the randomsampling hcr-walk inspired by the well-formulated variational inference.We experimentally validate the efficiency and effectiveness of our proposed VG-GCN,which has high computation speed,and the comparable or even better performance when compared with baseline GCNs.展开更多
Carbon fiber reinforced polymer(CFRP)and CFRP-based composite honeycomb sandwich structures are particularly sensitive to impact.The mechanical characteristics of composite honeycomb sandwich structures under oblique ...Carbon fiber reinforced polymer(CFRP)and CFRP-based composite honeycomb sandwich structures are particularly sensitive to impact.The mechanical characteristics of composite honeycomb sandwich structures under oblique impact are studied by numerical simulation and experiment.The oblique impact model is established,and the reliability of the model is verified by the oblique impact test.To further analyze the influence of structural parameters on energy absorption under oblique impact,the influence of impact angle,face sheet thickness and wall thickness of the honeycomb is numerically studied.The results show that the impact angle has an important effect on energy distribution.The structural parameters also have an effect on the peak contact force,contact time,and energy absorption,and the effect is different from normal impact due to the presence of frictional dissipation energy.Compared with normal impact,the debonding of oblique impact will be reduced,but the buckling range of the honeycomb core will be expanded.展开更多
Fish behavior refers to various movements of fish. Fish behavior is closely related to the ecology of fish, physiological changes of fish, aquaculture and so on. Related applications will be expanded if fish behavior ...Fish behavior refers to various movements of fish. Fish behavior is closely related to the ecology of fish, physiological changes of fish, aquaculture and so on. Related applications will be expanded if fish behavior is analyzed properly. Traditional analysis of fish behavior mainly relies on the observation of human eyes. With the deepening and extension of application and the rapid development of computer technology, computer vision technology is increasingly used to analyze fish behaviors. This paper summarized the research status, research progress and main problems of fish behavior analysis by using computer vision and made forecast about future research.展开更多
In order to solve the problem of unsatisfactory detection effect of underwater visual saliency map, an image saliency detection algorithm based on improved histogram equalization is proposed. Underwater images are oft...In order to solve the problem of unsatisfactory detection effect of underwater visual saliency map, an image saliency detection algorithm based on improved histogram equalization is proposed. Underwater images are often not clear enough because the refraction of light underwater causes insufficient image resolution. Therefore, in order to solve the existing problems of traditional histogram equalization algorithm, an improved histogram equalization method is proposed to enhance the quality of images, which makes the saliency regions smoother and clearer. In this paper, the simulation experiments were conducted on UIEBD dataset and DLOU_underwater dataset. The experimental results show the effectiveness, robustness and accuracy of the proposed algorithm.展开更多
Exosomes(EXOs)have showed great potential in regenerative medicine.The separation of EXOs from complex biological media is essential for the down-stream applications.Herein,we report a deoxyribonucleic acid(DNA)-based...Exosomes(EXOs)have showed great potential in regenerative medicine.The separation of EXOs from complex biological media is essential for the down-stream applications.Herein,we report a deoxyribonucleic acid(DNA)-based micro-complex(DMC)containing polyaptamers,which realized the specific separation of EXOs from cell culture media and the significant promotion of wound healing.The synthesis of DMCs was based on a biomineralization process via rolling circle amplification(RCA)under the catalysis of phi29 DNA polymerase.To endow DMCs with the ability to capture EXOs,the DNA template of RCA was integrated with complementary sequence of aptamer that specifically recognized the CD63 proteins on EXOs.The obtained DMCs contained polyaptamers that can specifically capture the EXOs in cell culture media.The EXOs-capturing DMCs were collected by centrifugation,achieving the separation of EXOs.Mesenchymal stem cell(MSC)-derived EXOs(MSC-EXOs)were separated by this DMC-based strategy,and the separated MSC-EXOs significantly enhanced the migration ability of cells.In particular,the significant therapeutic efficacy of the DMCs with MSC-EXOs was verified in full-thickness wound excision mouse models,in which the wounds completely healed in 10 days.We envision that this DMC-based separation strategy can be a promising route to promote the development of EXOs in biomedicine.展开更多
During dislocation,a tunnel crossing the active fault will be damaged to varying degrees due to its permanent stratum displacement.Most previous studies did not consider the influence of the tunnel’s deep burial and ...During dislocation,a tunnel crossing the active fault will be damaged to varying degrees due to its permanent stratum displacement.Most previous studies did not consider the influence of the tunnel’s deep burial and the high in-situ stress,so the results were not entirely practical.In this paper,the necessity of solving the anti-dislocation problem of deep-buried tunnels is systemically discussed.Through the model test of tunnels across active faults,the differences in failures between deep-buried tunnels and shallow-buried tunnels were compared,and the dislocation test of deep-buried segmental tunnels was carried out to analyze the external stress change,lining strain,and failure mode of tunnels.The results are as follows.(1)The overall deformation of deep-buried and shallow-buried tunnels is both Sshaped.The failure mode of deep-buried tunnels is primarily characterized by shear and tensile failure,resulting in significant compressive deformation and a larger damaged area.In contrast,shallow-buried tunnels mainly experience shear failure,with the tunnel being sheared apart at the fault crossing,leading to more severe damage.(2)After the segmental structure design of the deep-buried tunnel,the‘‘S”deformation pattern is transformed into a‘‘ladder”pattern,and the strain of the tunnel and the peak stress of the external rock mass are reduced;therefore,damages are significantly mitigated.(3)Through the analysis of the distribution of cracks in the tunnel lining,it is found that the tunnel without a segmental structure design has suffered from penetrating failure and that cracks affect the entire lining.The cracks in a flexible segmental tunnel affect about 66.6%of the entire length of the tunnel,and cracks in a tunnel with a short segmental tunnel only affect about 33.3%of the entire length of the tunnel.Therefore,a deep-buried tunnel with a short segmental tunnel can yield a better anti-dislocation effect.(4)By comparing the shallow-buried segmental tunnel in previous studies,it is concluded that the shallow-buried segmental tunnel will also suffer from deformation outside the fault zone,while the damages to the deep-buried segmental tunnel are concentrated in the fault zone,so the anti-dislocation protection measures of the deep-buried tunnel shall be provided mainly in the fault zone.The results of the above study can provide theoretical reference and technical support for the design and reinforcement measures of the tunnel crossing active fault under high in-situ stress conditions.展开更多
Dear Editor,Two distinct pathways,non-homologous end joining(NHEJ)and homologous recombination(HR)repair,have evolved to repair DNA double-strand breaks(DSBs),the most deleterious type of DNA damage.Impaired NHEJ and ...Dear Editor,Two distinct pathways,non-homologous end joining(NHEJ)and homologous recombination(HR)repair,have evolved to repair DNA double-strand breaks(DSBs),the most deleterious type of DNA damage.Impaired NHEJ and HR are often associated with a high incidence of tumorigenesis and the early onset of aging.A number of methods and tools have been developed to help elucidate the regulatory mechanisms of the two repair pathways in the past.In vitro biochemical assays employ 32P-labeled broken DNA fragments and cell extracts to evaluate DSB repair capacity.At DSB sites,several DSB repair factors form foci,which can be visualized through immunofluorescence and microscopy.Among them,phosphorylated H2AX at the Ser139 residue is often considered a DSB marker,and its formation and removal at different time points post the induction of DSBs can be used to reflect the repair capacity and genomic instability.In addition,by quantifying the kinetics of the recruitment of specific NHEJ and HR factors such as 53BP1,DNA-PKcs,MRE11,RPA2,and RAD51,one would be able to make judgments on whether NHEJ,HR,or both pathways is/are affected and sometimes at which steps DSB repair pathways are regulated.An alternative approach for kinetic analysis is to quantify the microirradiation-induced recruitment of repair factors.Moreover,comet assays are also utilized to measure DNA damage-induced genomic stability at the single-cell level.However,with these assays,it is still difficult to measure NHEJ and HR efficiency in a relatively less time-consuming and more quantitative manner.展开更多
The emergence of adapted variants of the SARS-CoV-2 virus has led to a surge in breakthrough infections worldwide.A recent analysis of immune responses in people who received inactivated vaccines has revealed that ind...The emergence of adapted variants of the SARS-CoV-2 virus has led to a surge in breakthrough infections worldwide.A recent analysis of immune responses in people who received inactivated vaccines has revealed that individuals with no prior infection have limited resistance to Omicron and its sub-lineages,while those with previous infections exhibit a significant amount of neutralizing antibodies and memory B cells.However,specific T-cell responses remain largely unaffected by the mutations,indicating that T-cell-mediated cellular immunity can still provide protection.Moreover,the administration of a third dose of vaccine has resulted in a marked increase in the spectrum and duration of neutralizing antibodies and memory B cells in vivo,which has enhanced resistance to emerging variants such as BA.2.75 and BA.2.12.1.These results highlight the need to consider booster immunization for previously infected individuals and the development of novel vaccination strategies.The rapid spread of adapted variants of the SARS-CoV-2 virus presents a significant challenge to global health.The findings from this study underscore the importance of tailoring vaccination strategies based on individual immune backgrounds and the potential need for booster shots to combat emerging variants.Continued research and development are crucial to discovering new immunization strategies that will effectively protect public health against the evolving virus.展开更多
We study the Cesaro means related to the divisor function. We show that the DDT Theorem holds over square-free numbers in short interval, which generalizes some results established by Deshouillers-Dress-Tenenbaum and ...We study the Cesaro means related to the divisor function. We show that the DDT Theorem holds over square-free numbers in short interval, which generalizes some results established by Deshouillers-Dress-Tenenbaum and by Cui-Wu.展开更多
In this paper, we establish a quite general mean value result of arithmetic functions over short intervals with the Selberg-Delange method and give some applications. In particular, we generalize Selberg's result ...In this paper, we establish a quite general mean value result of arithmetic functions over short intervals with the Selberg-Delange method and give some applications. In particular, we generalize Selberg's result on the distribution of integers with a given number of prime factors and Deshouillers-Dress-Tenenbaum's arcsin law on divisors to the short interval case.展开更多
With the development of fishery industry,accurate estimation of the number of fish in aquaculture waters is of great importance to fish behavior analysis,bait feeding and fishery resource investigation.In this paper,w...With the development of fishery industry,accurate estimation of the number of fish in aquaculture waters is of great importance to fish behavior analysis,bait feeding and fishery resource investigation.In this paper,we propose a method for fish density estimation based on the multi-scale context enhanced convolutional network,which could map a fish school image taken at any angle to a density map,and calculate the number of fish in the image finally.In order to eliminate the influence of camera perspective effect and image resolution on density estimation,multi-scale filters are utilized in a convolutional neural network to process fish image in parallel.And then,the context enhancement module is merged in the network structure to help the network understand the global context information of the image.Finally,different feature maps are merged together to construct the density map of fish school images,and finally get the number of fish in the image.In order to make the effectiveness of our method valid,we test the proposed method on DlouDataset.The results show that the proposed method has lower mean square error and mean absolute error,which is helpful to improve the accuracy of the fish counting in dense fish school images.展开更多
The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic,urgently requiring effective countermeasures against its rapid expansion.All available vaccine platforms are being us...The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic,urgently requiring effective countermeasures against its rapid expansion.All available vaccine platforms are being used to generate safe and effective COVID-19 vaccines.Here,we generated a live-attenuated candidate vaccine strain by serial passaging of a SARSCoV-2 clinical isolate in Vero cells.展开更多
For arbitrary c00, if A is a subset of the primes less than x with cardinality δx(logx)-1, δ≥(logx)-c0, then there exists a positive constant c such that the cardinality of A+A is larger than cδx(loglogx)-1.
Dear Editor,The COVID-19 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), has led to millions of lives lost worldwide. The trimeric spike protein(S) decorating the membrane sur...Dear Editor,The COVID-19 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), has led to millions of lives lost worldwide. The trimeric spike protein(S) decorating the membrane surface of the infectious virion is responsible for the attachment and entry by binding to the receptor angiotensin-converting enzyme 2(ACE2) in the early replication cycle(Zhou P. et al., 2020). Two subunits S1 and S2 are included in the trimeric glycoprotein.展开更多
Caveolae,the specialized cell-surface plasma membrane invaginations which are abundant in endothelial cells,play critical roles in regulating various cellular processes,including cholesterol homeostasis,nitric oxide p...Caveolae,the specialized cell-surface plasma membrane invaginations which are abundant in endothelial cells,play critical roles in regulating various cellular processes,including cholesterol homeostasis,nitric oxide production,and signal transduction.Endothelial caveolae serve as a membrane platform for compartmentalization,modulation,and integration of signal events associated with endothelial nitric oxide synthase,ATP synthaseβ,and integrins,which are involved in the regulation of endothelial dysfunction and related cardiovascular diseases,such as atherosclerosis and hypertension.Furthermore,these dynamic microdomains on cell membrane are modulated by various extracellular stimuli,including cholesterol and flow shear stress.In this brief review,we summarize the critical roles of caveolae in the orchestration of endothelial function based on recent findings as well as our work over the past two decades.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42377182,52079133 and 41931295).
文摘The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of attention.In this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold boxes.Cyclic shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear rate.The results indicate that the shear stress vs.shear displacement curves under each shear cycle and the peak shear strength vs.cyclic number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with mudstone.The peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing conditions.The normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.
基金supported by the National Natural Science Foundation of China(No.52079133)CRSRI Open Research Program(Program SN:CKWV2019746/KY)+1 种基金the project of Key Laboratory of Water Grid Project and Regulation of Ministry of Water Resources(QTKS0034W23291)the Youth Innovation Promotion Association CAS.
文摘Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.
基金The Joint Funds of the National Natural Science Foundation of China under contract Nos U22A20580 and U2106203the National Natural Science Foundation of China under contract No.41706067the Open Project Program of Key Laboratory of Ecological Warning,Protection&Restoration for Bohai Sea,Ministry of Natural Resources under contract No.2022108.
文摘Naturally occurring radium(^(223)Ra,^(224)Ra,^(226)Ra,and^(228)Ra)isotopes have been widely applied as geochemical tracers in marine environments,especially when estimating the submarine groundwater discharge(SGD).In this sense,the influencing factors and transport mechanism of radium isotope activity in aquifers can be key information for SGD estimation.This work evaluates the adsorption/desorption behavior of^(224)Ra and^(226)Ra in the solid-liquid phase through a leaching experiment and analysis of field data.The results suggested that radium isotope activity was positively correlated with salinity and grain size,in the case of abundant sediments.Through ion analysis,we found that the ions(Na^(+),Ca^(2+),Mg^(2+),and Ba^(2+))exchanged with radium isotopes in the process of transport.A 1-D reactive transport model was established to simulate the transport process of radium isotope in aquifers.The model successfully simulated the variation of radium isotope desorption activity with salinity and was subsequently verified in the field.This study contributes to the understanding of the geochemical behavior of radium isotopes in aquifers and provides guidance for selecting a suitable groundwater endmember in SGD estimation.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20190019,BK20190452)the National Natural Science Foundation of China(62072244,61906094)the Natural Science Foundation of Shandong Province(ZR2020LZH008)。
文摘The existing graph convolution methods usually suffer high computational burdens,large memory requirements,and intractable batch-processing.In this paper,we propose a high-efficient variational gridded graph convolution network(VG-GCN)to encode non-regular graph data,which overcomes all these aforementioned problems.To capture graph topology structures efficiently,in the proposed framework,we propose a hierarchically-coarsened random walk(hcr-walk)by taking advantage of the classic random walk and node/edge encapsulation.The hcr-walk greatly mitigates the problem of exponentially explosive sampling times which occur in the classic version,while preserving graph structures well.To efficiently encode local hcr-walk around one reference node,we project hcrwalk into an ordered space to form image-like grid data,which favors those conventional convolution networks.Instead of the direct 2-D convolution filtering,a variational convolution block(VCB)is designed to model the distribution of the randomsampling hcr-walk inspired by the well-formulated variational inference.We experimentally validate the efficiency and effectiveness of our proposed VG-GCN,which has high computation speed,and the comparable or even better performance when compared with baseline GCNs.
基金This research was supported by the National Natural Science Foundations of China(Nos.52175153,U1833116,51705468 and 11402234)the China Scholarship Council(CSC).
文摘Carbon fiber reinforced polymer(CFRP)and CFRP-based composite honeycomb sandwich structures are particularly sensitive to impact.The mechanical characteristics of composite honeycomb sandwich structures under oblique impact are studied by numerical simulation and experiment.The oblique impact model is established,and the reliability of the model is verified by the oblique impact test.To further analyze the influence of structural parameters on energy absorption under oblique impact,the influence of impact angle,face sheet thickness and wall thickness of the honeycomb is numerically studied.The results show that the impact angle has an important effect on energy distribution.The structural parameters also have an effect on the peak contact force,contact time,and energy absorption,and the effect is different from normal impact due to the presence of frictional dissipation energy.Compared with normal impact,the debonding of oblique impact will be reduced,but the buckling range of the honeycomb core will be expanded.
基金Guangdong Province Key Laboratory of Popular High Performance Computers (SZU-GDPHPCL201805)Institute of Marine Industry Technology of Universities in Liaoning Province (2018-CY-34)+2 种基金National Natural Science Foundation of China (61701070)Liaoning Doctoral Start-up Fund (20180540090)China Postdoctoral Science Foundation (2018M640239).
文摘Fish behavior refers to various movements of fish. Fish behavior is closely related to the ecology of fish, physiological changes of fish, aquaculture and so on. Related applications will be expanded if fish behavior is analyzed properly. Traditional analysis of fish behavior mainly relies on the observation of human eyes. With the deepening and extension of application and the rapid development of computer technology, computer vision technology is increasingly used to analyze fish behaviors. This paper summarized the research status, research progress and main problems of fish behavior analysis by using computer vision and made forecast about future research.
基金Guangdong Province Key Laboratory of Popular High Performance Computers (SZU-GDPHPCL201805)Institute of Marine Industry Technology of Universities in Liaoning Province (2018-CY-34)China Postdoctoral Science Foundation (2018M640239).
文摘In order to solve the problem of unsatisfactory detection effect of underwater visual saliency map, an image saliency detection algorithm based on improved histogram equalization is proposed. Underwater images are often not clear enough because the refraction of light underwater causes insufficient image resolution. Therefore, in order to solve the existing problems of traditional histogram equalization algorithm, an improved histogram equalization method is proposed to enhance the quality of images, which makes the saliency regions smoother and clearer. In this paper, the simulation experiments were conducted on UIEBD dataset and DLOU_underwater dataset. The experimental results show the effectiveness, robustness and accuracy of the proposed algorithm.
基金supported by Tianjin Health Science and Technology Research Project(No.TJWJ2021MS005)National Natural Science Foundation of China(No.22174097).
文摘Exosomes(EXOs)have showed great potential in regenerative medicine.The separation of EXOs from complex biological media is essential for the down-stream applications.Herein,we report a deoxyribonucleic acid(DNA)-based micro-complex(DMC)containing polyaptamers,which realized the specific separation of EXOs from cell culture media and the significant promotion of wound healing.The synthesis of DMCs was based on a biomineralization process via rolling circle amplification(RCA)under the catalysis of phi29 DNA polymerase.To endow DMCs with the ability to capture EXOs,the DNA template of RCA was integrated with complementary sequence of aptamer that specifically recognized the CD63 proteins on EXOs.The obtained DMCs contained polyaptamers that can specifically capture the EXOs in cell culture media.The EXOs-capturing DMCs were collected by centrifugation,achieving the separation of EXOs.Mesenchymal stem cell(MSC)-derived EXOs(MSC-EXOs)were separated by this DMC-based strategy,and the separated MSC-EXOs significantly enhanced the migration ability of cells.In particular,the significant therapeutic efficacy of the DMCs with MSC-EXOs was verified in full-thickness wound excision mouse models,in which the wounds completely healed in 10 days.We envision that this DMC-based separation strategy can be a promising route to promote the development of EXOs in biomedicine.
基金supported by the National Key R&D Programs for Young Scientists of China(Grant No.2023YFB2390400)the National Natural Science Foundation of China(Grant Nos.U21A20159,52079133,52379112,and 41902288)+2 种基金Key Research Program of First Survey and Design Institute(Grant No.2022KY56(ZDZX)-02)Key Research Program of the Ministry of Water Resources of China(Grant No.SKS-2022103)Yunnan Major Science and Technology Special Program(Grant No.202102AF080001).
文摘During dislocation,a tunnel crossing the active fault will be damaged to varying degrees due to its permanent stratum displacement.Most previous studies did not consider the influence of the tunnel’s deep burial and the high in-situ stress,so the results were not entirely practical.In this paper,the necessity of solving the anti-dislocation problem of deep-buried tunnels is systemically discussed.Through the model test of tunnels across active faults,the differences in failures between deep-buried tunnels and shallow-buried tunnels were compared,and the dislocation test of deep-buried segmental tunnels was carried out to analyze the external stress change,lining strain,and failure mode of tunnels.The results are as follows.(1)The overall deformation of deep-buried and shallow-buried tunnels is both Sshaped.The failure mode of deep-buried tunnels is primarily characterized by shear and tensile failure,resulting in significant compressive deformation and a larger damaged area.In contrast,shallow-buried tunnels mainly experience shear failure,with the tunnel being sheared apart at the fault crossing,leading to more severe damage.(2)After the segmental structure design of the deep-buried tunnel,the‘‘S”deformation pattern is transformed into a‘‘ladder”pattern,and the strain of the tunnel and the peak stress of the external rock mass are reduced;therefore,damages are significantly mitigated.(3)Through the analysis of the distribution of cracks in the tunnel lining,it is found that the tunnel without a segmental structure design has suffered from penetrating failure and that cracks affect the entire lining.The cracks in a flexible segmental tunnel affect about 66.6%of the entire length of the tunnel,and cracks in a tunnel with a short segmental tunnel only affect about 33.3%of the entire length of the tunnel.Therefore,a deep-buried tunnel with a short segmental tunnel can yield a better anti-dislocation effect.(4)By comparing the shallow-buried segmental tunnel in previous studies,it is concluded that the shallow-buried segmental tunnel will also suffer from deformation outside the fault zone,while the damages to the deep-buried segmental tunnel are concentrated in the fault zone,so the anti-dislocation protection measures of the deep-buried tunnel shall be provided mainly in the fault zone.The results of the above study can provide theoretical reference and technical support for the design and reinforcement measures of the tunnel crossing active fault under high in-situ stress conditions.
基金the Chinese National Program on the Key Basic Research Project(2018YFC2000100 and 2021YFA1102000 to Z.M.)the National Natural Science Foundation of China(31871438 and 82071565 to Z.M.,81972457 and 32171288 to Y.J.)+2 种基金the“Shu Guang”project supported by the Shanghai Municipal Education Commission and Shanghai Education Development Foundation(19SG18 to Z.M.)the Program of the Shanghai Academic Research Leader(19XD1403000 to Z.M.)the Shanghai Sailing Program(22YF1434300 to Y.C.).
文摘Dear Editor,Two distinct pathways,non-homologous end joining(NHEJ)and homologous recombination(HR)repair,have evolved to repair DNA double-strand breaks(DSBs),the most deleterious type of DNA damage.Impaired NHEJ and HR are often associated with a high incidence of tumorigenesis and the early onset of aging.A number of methods and tools have been developed to help elucidate the regulatory mechanisms of the two repair pathways in the past.In vitro biochemical assays employ 32P-labeled broken DNA fragments and cell extracts to evaluate DSB repair capacity.At DSB sites,several DSB repair factors form foci,which can be visualized through immunofluorescence and microscopy.Among them,phosphorylated H2AX at the Ser139 residue is often considered a DSB marker,and its formation and removal at different time points post the induction of DSBs can be used to reflect the repair capacity and genomic instability.In addition,by quantifying the kinetics of the recruitment of specific NHEJ and HR factors such as 53BP1,DNA-PKcs,MRE11,RPA2,and RAD51,one would be able to make judgments on whether NHEJ,HR,or both pathways is/are affected and sometimes at which steps DSB repair pathways are regulated.An alternative approach for kinetic analysis is to quantify the microirradiation-induced recruitment of repair factors.Moreover,comet assays are also utilized to measure DNA damage-induced genomic stability at the single-cell level.However,with these assays,it is still difficult to measure NHEJ and HR efficiency in a relatively less time-consuming and more quantitative manner.
基金supported by National Natural Science Foundation of China(92159302 to W.M.L.)the Fundamental Research Funds for the Central Universities(SCU2022D025 to W.M.L.)+2 种基金Science and Technology Foundation of Sichuan Province,China(2022NSFSC0842 to W.X.L.,2020YFS0572 to L.Y.L.)Ministry of Science and Technology of China(EKPG21-09 and CPL-1233)supported by Ten Thousand Talent Program and the NSFS Innovative Research Group(No.81921005).
文摘The emergence of adapted variants of the SARS-CoV-2 virus has led to a surge in breakthrough infections worldwide.A recent analysis of immune responses in people who received inactivated vaccines has revealed that individuals with no prior infection have limited resistance to Omicron and its sub-lineages,while those with previous infections exhibit a significant amount of neutralizing antibodies and memory B cells.However,specific T-cell responses remain largely unaffected by the mutations,indicating that T-cell-mediated cellular immunity can still provide protection.Moreover,the administration of a third dose of vaccine has resulted in a marked increase in the spectrum and duration of neutralizing antibodies and memory B cells in vivo,which has enhanced resistance to emerging variants such as BA.2.75 and BA.2.12.1.These results highlight the need to consider booster immunization for previously infected individuals and the development of novel vaccination strategies.The rapid spread of adapted variants of the SARS-CoV-2 virus presents a significant challenge to global health.The findings from this study underscore the importance of tailoring vaccination strategies based on individual immune backgrounds and the potential need for booster shots to combat emerging variants.Continued research and development are crucial to discovering new immunization strategies that will effectively protect public health against the evolving virus.
基金Acknowledgements The authors are indebted to the anonymous referees for valuable suggestions, which led to Lemma 2 in its present shape. The first author is especially grateful to his supervisor, Prof. Hongze Li, for his unending encouragement and his effort that provides the opportunities to communicate with foreign specialists. This work was supported in part by the National Natural Science Foundation of China (Grant No. 11271249) and the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20120073110059).
文摘We study the Cesaro means related to the divisor function. We show that the DDT Theorem holds over square-free numbers in short interval, which generalizes some results established by Deshouillers-Dress-Tenenbaum and by Cui-Wu.
基金supported by National Natural Science Foundation of China (Grant Nos. 11671253, 11771252 and 11531008)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20120073110059)+1 种基金Program for Innovative Research Team in University of Ministry of Education of China (Grant No. IRT16R43)Taishan Scholars Project, the Program PRC 1457-AuForDiP (CNRS-NSFC)
文摘In this paper, we establish a quite general mean value result of arithmetic functions over short intervals with the Selberg-Delange method and give some applications. In particular, we generalize Selberg's result on the distribution of integers with a given number of prime factors and Deshouillers-Dress-Tenenbaum's arcsin law on divisors to the short interval case.
基金This work is supported by Institute of Marine Industry Technology of Universities in Liaoning Province(2018-CY-34)National Natural Science Foundation of China(31972846)+1 种基金China Postdoctoral Science Foundation(2018M640239)Acknowledgement for the Data Support from National Marine Science Data Center(Dalian),National Science&Technology Resource Sharing Service Platform of China(http://odc.dlou.edu.cn/).
文摘With the development of fishery industry,accurate estimation of the number of fish in aquaculture waters is of great importance to fish behavior analysis,bait feeding and fishery resource investigation.In this paper,we propose a method for fish density estimation based on the multi-scale context enhanced convolutional network,which could map a fish school image taken at any angle to a density map,and calculate the number of fish in the image finally.In order to eliminate the influence of camera perspective effect and image resolution on density estimation,multi-scale filters are utilized in a convolutional neural network to process fish image in parallel.And then,the context enhancement module is merged in the network structure to help the network understand the global context information of the image.Finally,different feature maps are merged together to construct the density map of fish school images,and finally get the number of fish in the image.In order to make the effectiveness of our method valid,we test the proposed method on DlouDataset.The results show that the proposed method has lower mean square error and mean absolute error,which is helpful to improve the accuracy of the fish counting in dense fish school images.
基金This work was supported by the National Key Research and Development Program of China(No.2020YFC0840900,2018YFA0900801 and 2020YFA0707500)the Strategic Priority Research Program(XDB29010000,XDB37030000),CAS(YSBR-010)+5 种基金the Emergency Key Programof Guangzhou Laboratory(No.EKPG21-09)the Beijing Municipal Science and Technology Project(No.Z201100001020004,Z201100005420017)the National Natural Science Foundation of China(No.82171820,No.12034006,and No.81921005)C.-F.Q.was supported by the National Science Fund for Distinguished Young Scholars(81925025)the Innovative Research Group(81621005)from the NSFCthe Innovation Fund forMedical Sciences(2019-I2 M-5-049)from the Chinese Academy of Medical Sciences.
文摘The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic,urgently requiring effective countermeasures against its rapid expansion.All available vaccine platforms are being used to generate safe and effective COVID-19 vaccines.Here,we generated a live-attenuated candidate vaccine strain by serial passaging of a SARSCoV-2 clinical isolate in Vero cells.
基金Supported by National Natural Science Foundation of China (Grant No.11271249)Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20120073110059)
文摘For arbitrary c00, if A is a subset of the primes less than x with cardinality δx(logx)-1, δ≥(logx)-c0, then there exists a positive constant c such that the cardinality of A+A is larger than cδx(loglogx)-1.
基金partially supported by the National Basic Research Program of China (2015CB351802)the National Natural Science Foundation of China (Grant Nos.61390511,61222211, 61379083,61271445)+1 种基金the Strategic Priority Research Program of the CAS (XDB02070004) the Youth Innovation Promotion Association CAS (2015085).
基金supported by funding from Beijing Natural Science Foundation-Haidian Primitive Innovation Joint fund(L192008)the National Key R&D Program(2020YFA0707500,2018YFA0900801,2021YFA1301400)the National Natural Science Foundation of China(31872730 and 32070947)
文摘Dear Editor,The COVID-19 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), has led to millions of lives lost worldwide. The trimeric spike protein(S) decorating the membrane surface of the infectious virion is responsible for the attachment and entry by binding to the receptor angiotensin-converting enzyme 2(ACE2) in the early replication cycle(Zhou P. et al., 2020). Two subunits S1 and S2 are included in the trimeric glycoprotein.
基金supported by National Key Research and Development Program of China Grant(2019YFA0802003)National Natural Science Foundation of China Grants(81730014,81790621,82070451,and 81870313)+1 种基金Young Elite Scientists Sponsorship Program by CAST(2019QNRC001)Tianjin Municipal Science and Technology Project(18JCZDJC44900 and 17JCJQJC45700)。
文摘Caveolae,the specialized cell-surface plasma membrane invaginations which are abundant in endothelial cells,play critical roles in regulating various cellular processes,including cholesterol homeostasis,nitric oxide production,and signal transduction.Endothelial caveolae serve as a membrane platform for compartmentalization,modulation,and integration of signal events associated with endothelial nitric oxide synthase,ATP synthaseβ,and integrins,which are involved in the regulation of endothelial dysfunction and related cardiovascular diseases,such as atherosclerosis and hypertension.Furthermore,these dynamic microdomains on cell membrane are modulated by various extracellular stimuli,including cholesterol and flow shear stress.In this brief review,we summarize the critical roles of caveolae in the orchestration of endothelial function based on recent findings as well as our work over the past two decades.