The annual mean volume and heat transport sketches through the inter-basin passages and transoceanic sections have been constructed based on 1400-year spin up results of the MOM4p 1. The spin up starts from a state of...The annual mean volume and heat transport sketches through the inter-basin passages and transoceanic sections have been constructed based on 1400-year spin up results of the MOM4p 1. The spin up starts from a state of rest, driven by the monthly climatological mean force from the NOAAWorld Ocean Atlas （1994）. The volume transport sketch reveals the northward transport throughout the Pacific and southward transport at all latitudes in the Atlantic. The annual mean strength of the Pacific-Arctic-Atlantic through flow is 0.63x106 m3/s in the Bering Strait. The majority of the northward volume transport in the southern Pacific turns into the Indonesian through flow （ITF） and joins the Indian Ocean equatorial current, which subse- quently flows out southward from the Mozambique Channel, with its majority superimposed on the Ant- arctic Circumpolar Current （ACC）. This anti-cyclonic circulation around Australia has a strength of 11 x 106 ms /s according to the model-produced result. The atmospheric fresh water transport, known as P-E^R （pre- cipitation minus evaporation plus runoff）, constructs a complement to the horizontal volume transport of the ocean. The annual mean heat transport sketch exhibits a northward heat transport in the Atlantic and poleward heat transport in the global ocean. The surface heat flux acts as a complement to the horizontal heat transport of the ocean. The climatological volume transports describe the most important features through the inter-basin passages and in the associated basins, including： the positive P-E＋R in the Arctic substantially strengthening the East Greenland Current in summer; semiannual variability of the volume transport in the Drake Passage and the southern Atlantic-Indian Ocean passage; and annual transport vari- ability of the ITF intensifying in the boreal summer. The climatological heat transports show heat storage in July and heat deficit in January in the Arctic; heat storage in January and heat deficit in July in the Antarctic circumpolar current regime （ACCR）; and intensified heat transport of the iTF in July. The volume transport of the ITF is synchronous with the volume transport through the southern Indo-Pacific sections, but the year-long southward heat transport of the ITF is out of phase with the heat transport through the equatorial Pacific, which is northward before May and southward after May. This clarifies the majority of the ITF origi- natinR from the southern Pacific Ocean.展开更多
This article discussed a study by Almahasneh et al,which investigated how high glucose and severe hypoxia affected mesenchymal stem cells(MSCs)at different passages.This research provides insights into the resilience ...This article discussed a study by Almahasneh et al,which investigated how high glucose and severe hypoxia affected mesenchymal stem cells(MSCs)at different passages.This research provides insights into the resilience of higher-passage MSCs under stress conditions,challenging the common use of lower passage MSCs in clinical settings.While this study offers valuable perspectives on the adaptability of MSCs,it relies mainly on in vitro results from a single cell line,limiting broader applicability.It highlights the need for more comprehensive in vivo studies to validate these findings and better understand MSC behavior in clinical scenarios.展开更多
Pressure and proximity measurements made in a tunnel indicate that a typical vehicle passage produced on the tunnel roof an initial pressure increase of small magnitude,followed by a sharp and more substantial drop in...Pressure and proximity measurements made in a tunnel indicate that a typical vehicle passage produced on the tunnel roof an initial pressure increase of small magnitude,followed by a sharp and more substantial drop in pressure below atmospheric.The magnitude of the pressure drop was found to increase with smaller clearances between the vehicle top and the tunnel roof,consistent with the Bernoulli relation and the vehicle speed.The dynamic pressures potentially may have significant effects on the vibration and noise environments on the lower floors of“air rights construction”buildings that span highways.展开更多
BACKGROUND Mesenchymal stem cells(MSCs)have been extensively studied for therapeutic potential,due to their regenerative and immunomodulatory properties.Serial passage and stress factors may affect the biological char...BACKGROUND Mesenchymal stem cells(MSCs)have been extensively studied for therapeutic potential,due to their regenerative and immunomodulatory properties.Serial passage and stress factors may affect the biological characteristics of MSCs,but the details of these effects have not been recognized yet.AIM To investigate the effects of stress factors(high glucose and severe hypoxia)on the biological characteristics of MSCs at different passages,in order to optimize the therapeutic applications of MSCs.METHODS In this study,we investigated the impact of two stress conditions;severe hypoxia and high glucose on human adipose-tissue derived MSCs(hAD-MSCs)at passages 6(P6),P8,and P10.Proliferation,senescence and apoptosis were evaluated measuring WST-1,senescence-associated beta-galactosidase,and annexin V,respectively.RESULTS Cells at P6 showed decreased proliferation and increased apoptosis under conditions of high glucose and hypoxia compared to control,while the extent of senescence did not change significantly under stress conditions.At P8 hAD-MSCs cultured in stress conditions had a significant decrease in proliferation and apoptosis and a significant increase in senescence compared to counterpart cells at P6.Cells cultured in high glucose at P10 had lower proliferation and higher senescence than their counterparts in the previous passage,while no change in apoptosis was observed.On the other hand,MSCs cultured under hypoxia showed decreased senescence,increased apoptosis and no significant change in proliferation when compared to the same conditions at P8.CONCLUSION These results indicate that stress factors had distinct effects on the biological processes of MSCs at different passages,and suggest that senescence may be a protective mechanism for MSCs to survive under stress conditions at higher passage numbers.展开更多
Elbow-inlet passage is widely used in large drainage pumping stations.Flow uniformity at the exit section directly determines its hydraulic performance.Flow uniformity must be optimized to improve the operational effi...Elbow-inlet passage is widely used in large drainage pumping stations.Flow uniformity at the exit section directly determines its hydraulic performance.Flow uniformity must be optimized to improve the operational efficiency of the large axial-flow pumping station.Modeling and numerical simulation methods were used to investigate the elbow-inlet passage,and the accuracy of the calculation results was verified.The key geometric parameters affecting the uniformity of the flow were optimized by the orthogonal experiment design.The optimal schemes were obtained and compared with the original scheme.The results show that flow uniformity V u after optimization is 95.41%,which is increased by 1.04%.The pumping station efficiency is increased by 1.89%,thereby confirming the applicability and accuracy of the proposed scheme,especially for the optimization of flow uniformity of the exit section of the elbow-inlet passage.展开更多
Since its outbreak in 2019,Severe Acute Respiratory Syndrome Coronavirus 2(SARS-Co V-2)keeps surprising the medical community by evolving diverse immune escape mutations in a rapid and effective manner.To gain deeper ...Since its outbreak in 2019,Severe Acute Respiratory Syndrome Coronavirus 2(SARS-Co V-2)keeps surprising the medical community by evolving diverse immune escape mutations in a rapid and effective manner.To gain deeper insight into mutation frequency and dynamics,we isolated ten ancestral strains of SARS-Co V-2 and performed consecutive serial incubation in ten replications in a suitable and common cell line and subsequently analysed them using RT-q PCR and whole genome sequencing.Along those lines we hoped to gain fundamental insights into the evolutionary capacity of SARS-Co V-2 in vitro.Our results identified a series of adaptive genetic changes,ranging from unique convergent substitutional mutations and hitherto undescribed insertions.The region coding for spike proved to be a mutational hotspot,evolving a number of mutational changes including the already known substitutions at positions S:484 and S:501.We discussed the evolution of all specific adaptations as well as possible reasons for the seemingly inhomogeneous potential of SARS-Co V-2 in the adaptation to cell culture.The combination of serial passage in vitro with whole genome sequencing uncovers the immense mutational potential of some SARS-Co V-2 strains.The observed genetic changes of SARS-Co V-2 in vitro could not be explained solely by selectively neutral mutations but possibly resulted from the action of directional selection accumulating favourable genetic changes in the evolving variants,along the path of increasing potency of the strain.Competition among a high number of quasi-species in the SARS-Co V-2 in vitro population gene pool may reinforce directional selection and boost the speed of evolutionary change.展开更多
Although worldwide concern has been raised since the large-scale outbreak of highly pathogenic avian influenza in wild birds at Qinghai Lake,China in 2005,the factors responsible for the ability to kill waterfowl rema...Although worldwide concern has been raised since the large-scale outbreak of highly pathogenic avian influenza in wild birds at Qinghai Lake,China in 2005,the factors responsible for the ability to kill waterfowl remain unclear. The why and how questions of the H5N1 virus species-jump into its reservoir host need to be answered. In this report we test the pathogenicity and adaptation of Qinghai Lake (Clade 2.2) isolate to Muscovy ducks for further understanding of this virus. The isolate was highly pathogenic in ducks and retained its high pathogenicity even after 20 generations of passage in ducks. During the process of serial passages,only the NS gene developed non-synonymous substitutions,which caused two mutations in NS1 protein (Val23Ala and Leu207Pro) and one in NS2 (Phe55Leu). These mutations persisted immutably through all subsequent passages and the pathogenicity remained high,implying that highly pathogenic H5N1 virus remains stable in aquatic birds through oral transmission. Although the exact functions of these mutations are not known,our results provide an important foundation for further understanding the characteristics of the Qinghai Lake isolates.展开更多
Quantum computation requires coherently controlling the evolutions of qubits.Usually,these manipulations are implemented by precisely designing the durations(such as theπ-pulses)of the Rabi oscillations and tunable i...Quantum computation requires coherently controlling the evolutions of qubits.Usually,these manipulations are implemented by precisely designing the durations(such as theπ-pulses)of the Rabi oscillations and tunable interbit coupling.Relaxing this requirement,herein we show that the desired population transfers between the logic states can be deterministically realized(and thus quantum computation could be implemented)both adiabatically and non-adiabatically,by performing the duration-insensitive quantum manipulations.Our proposal is specifically demonstrated with the surface-state of electrons floating on the liquid helium,but could also be applied to the other artificially controllable systems for quantum computing.展开更多
To better understand the characteristics of a large-scaled parabolic trough solar field(PTSF)under cloud passages,a novel method which combines a closed-loop thermal hydraulic model(CLTHM)and cloud vector(CV)is develo...To better understand the characteristics of a large-scaled parabolic trough solar field(PTSF)under cloud passages,a novel method which combines a closed-loop thermal hydraulic model(CLTHM)and cloud vector(CV)is developed.Besides,the CLTHM is established and validated based on a pilot plant.Moreover,some key parameters which are used to characterize a typical PTSF and CV are presented for further simulation.Furthermore,two sets of results simulated by the CLTHM are compared and discussed.One set deals with cloud passages by the CV,while the other by the traditionally distributed weather stations(DWSs).Because of considering the solar irradiance distribution in a more detailed and realistically way,compared with the distributed weather station(DWS)simulation,all essential parameters,such as the total flowrate,flow distribution,outlet temperature,thermal and exergetic efficiency,and exergetic destruction tend to be more precise and smoother in the CV simulation.For example,for the runner outlet temperature,which is the most crucial parameter for a running PTSF,the maximum relative error reaches−15%in the comparison.In addition,the mechanism of thermal and hydraulic unbalance caused by cloud passages are explained based on the simulation.展开更多
The complex vortex structures in the flow around turbine rotor passages, with weak or strong, large or small vortices, interacting with each other, often generate most of aerodynamic loss in turbomachines. Therefore, ...The complex vortex structures in the flow around turbine rotor passages, with weak or strong, large or small vortices, interacting with each other, often generate most of aerodynamic loss in turbomachines. Therefore, it is important to identify the vortex structures accurately for the flow field analysis and the aerodynamic performance optimization for turbomachines. In this paper, by using 4 vortex identification methods (the Q criterion, the Q method, the Liutex method and the Q -Liutex method), the vortices are identified in turbine rotor passages. In terms of the threshold selection, the results show that the D method and the Q -Liutex method are more robust, by which strong and weak vortices can be visualized simultaneously over a wide range of thresholds. As for the display consistency of the vortex identification methods and the streamlines, it is shown that the Liutex method gives results coinciding best with the streamlines in identifying strong vortices, while the Q -Liutex method gives results the most consistent with the streamlines in identifying weak vortices. As to the relationship among the loss, the vortices and the shear, except for the Q criterion, the other three methods can distinguish the vortical regions from the high shear regions. And the flow losses in turbine rotor passages are often related to high shear zones, while there is a small loss within the core of the vortex. In order to obtain the variation of vortices in the turbine rotor passages at different working points, the Liutex method is applied in 2 cases of a turbine with different angles of attack. The identification results show that the strengths of the tip leakage vortex and the upper passage vortex are weaker and the distance between them is closer at a negative angle of attack. This indicates that the Liutex method is an effective method, and can be used to analyze the vortex structures and their evolution in turbine rotor passages.展开更多
Path planning is a crucial concern in the field of mobile robotics,particularly in complex scenarios featuring narrow passages.Sampling-based planners,such as the widely utilized probabilistic roadmap(PRM),have been e...Path planning is a crucial concern in the field of mobile robotics,particularly in complex scenarios featuring narrow passages.Sampling-based planners,such as the widely utilized probabilistic roadmap(PRM),have been extensively employed in various robot applications.However,PRM’s utilization of random node sampling often results in disconnected graphs,posing a significant challenge when dealing with narrow passages.In order to tackle this issue,we present equipotential line sampling strategy for probabilistic roadmap(EPL-PRM),a novel approach derived from PRM.This paper initially proposes a sampling potential field,followed by the construction of equipotential lines that are denser in the proximity of obstacles and narrow passages.Random sampling is subsequently conducted along these lines.Consequently,the sampling strategy enhances the likelihood of sampling nodes around obstacles and narrow passages,thereby addressing the issue of sparsity encountered in traditional sampling-based planners.Furthermore,we introduce a nodal optimization method based on an artificial repulsive field,which prompts sampled nodes to move in the direction of repulsion.As a result,nodes around obstacles are distributed more uniformly,while nodes within narrow passages gravitate toward the middle of the passages.Finally,extensive simulations are conducted to evaluate the proposed method.The results demonstrate that our approach achieves path planning with superior efficiency,lower cost,and higher reliability compared with traditional algorithms.展开更多
The wave rotor technology is an energy exchanging approach that achieves efficient energy transfer between gases without using mechanical components.The wave rotor technology has been successfully utilized in gas turb...The wave rotor technology is an energy exchanging approach that achieves efficient energy transfer between gases without using mechanical components.The wave rotor technology has been successfully utilized in gas turbine cycle systems,gas expansion refrigeration and a variety of other industrial domains,yielding numerous researches and application outcomes.The structure of wave rotor passages inside which the energy exchange between gases is realized has an important impact on the equipment performance.In this study,based on gas wave ejection technology,the first application trials of an expansion wave rotor with curved passages were conducted.Additionally,the performance enhancing effect and mechanism of curved passages on the energy exchanging process were studied precisely by the combination of experimental and three-dimensional numerical simulation methods.The experimental results demonstrate that the curved passage rotor(CIR rotor)employed in this research has a maximum isentropic efficiency of 61.6%,and the CIR rotor achieves higher efficiency than the straight passage rotor(STR rotor)on all working conditions in this study.Compared with the STR rotor,the maximum efficiency improving ratio of CIR rotor can exceed 14.2%at each experimental expansion ratio,and the maximum relative increments of ejection rate are more than 5%.In addition,the CIR rotor can also effectively increase the proportion of static pressure in total pressure of the medium-pressure gas,and reduce the device power consumption.The three-dimensional numerical investigations revealed the principle of gas ejection in the wave rotors and explained why the CIR rotor performed better.According to the numerical findings,the curved passages of the CIR rotor may effectively minimize various energy losses created in the processes of high-pressure gas incidence,exhausting flow in nozzle,and high-speed gas flow in the passages.展开更多
1Legal requirements The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and t...1Legal requirements The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.展开更多
1Legal requirements.The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and t...1Legal requirements.The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.展开更多
Satellite communication technology has emerged as a key solution to address the challenges of data transmission in remote areas.By overcoming the limitations of traditional terrestrial communication networks,it enable...Satellite communication technology has emerged as a key solution to address the challenges of data transmission in remote areas.By overcoming the limitations of traditional terrestrial communication networks,it enables long-distance data transmission anytime and anywhere,ensuring the timely and accurate delivery of water level data,which is particularly crucial for fishway water level monitoring.To enhance the effectiveness of fishway water level monitoring,this study proposes a multi-task learning model,AS-SOMTF,designed for real-time and comprehensive prediction.The model integrates auxiliary sequences with primary input sequences to capture complex relationships and dependencies,thereby improving representational capacity.In addition,a novel timeseries embedding algorithm,AS-SOM,is introduced,which combines generative inference and pooling operations to optimize prediction efficiency for long sequences.This innovation not only ensures the timely transmission of water level data but also enhances the accuracy of real-time monitoring.Compared with traditional models such as Transformer and Long Short-Term Memory(LSTM)networks,the proposed model achieves improvements of 3.8%and 1.4%in prediction accuracy,respectively.These advancements provide more precise technical support for water level forecasting and resource management in the Diqing Tibetan Autonomous Prefecture of the Lancang River,contributing to ecosystem protection and improved operational safety.展开更多
Alice opened the door and found that it led into a small passage,not much larger than a rat⁃hole:she knelt down and looked along the passage into the loveliest garden you ever saw.How she longed to get out of that dar...Alice opened the door and found that it led into a small passage,not much larger than a rat⁃hole:she knelt down and looked along the passage into the loveliest garden you ever saw.How she longed to get out of that dark hall,and wander about among those beds of bright flowers and those cool fountains,but she could not even get her head through the doorway;“and even if my head would go through,”thought poor Alice,“it would be of very little use without my shoulders.Oh,how I wish I could shut up like a telescope!I think I could,if I only know how to begin.”For,you see,so many out⁃of⁃the⁃way things had happened lately,that Alice had begun to think that very few things indeed were really impossible.展开更多
NEW MATTER MATTERS.Oriental Outlook.17 April.The Shenzhen-Zhongshan Link,a major cross-sea passage in Guangdong Province,stands as a testament to modern engineering.To meet the demands of its harsh marine environment,...NEW MATTER MATTERS.Oriental Outlook.17 April.The Shenzhen-Zhongshan Link,a major cross-sea passage in Guangdong Province,stands as a testament to modern engineering.To meet the demands of its harsh marine environment,Chinese researchers have developed an advanced protective coating.Reinforced with ultrathin materials,this innovative solution is designed to extend the lifespan of steel structures well beyond a century by shielding them from corrosion.展开更多
Oral squamous cell carcinoma(OSCC)constitutes 90%of oral tumors.Advanced cases severely impair patients'life quality of life due to anatomical location and limited therapies.Conventional treatments often induce dr...Oral squamous cell carcinoma(OSCC)constitutes 90%of oral tumors.Advanced cases severely impair patients'life quality of life due to anatomical location and limited therapies.Conventional treatments often induce drug resistance or recurrence.Patientderived xenograft(PDX)models are widely used to simulate tumor progression and drug responses,serving as translational tools for precision medicine.This study aimed to establish drug-resistant OSCC PDX models.Human OSCC tissues were transplanted into immunodeficient mice and passaged(P1–P2).At P2(tumor volume:40–80 mm^(3)),mice received cisplatin(1 mg/kg,three times/week)with cetuximab(1 mg/kg,weekly),GSK690693(10 mg/kg,five times/week),or rapamycin(4 mg/kg,five times/week).PDX tissues from groups with less-therapeutic response(manifested as larger tumor volumes)were serially passaged to assess treatment efficacy.Tumor tissues with diminished drug sensitivity underwent histopathological analysis and identified stability of their tumor characteristics using hematoxylin–eosin(HE)and immunohistochemical staining after one additional passage and retreatment.Results demonstrated that successive passaging accelerates tumor growth.First-generation treatments showed universal sensitivity.At P2,cisplatin–cetuximab and rapamycin groups remained sensitive,whereas GSK690693 efficacy declined.Continued passaging of GSK690693-treated tumors confirmed resistance,as evidenced by exhibiting enhanced malignant characteristics at histological level.The GSK690693-resistant model was established first,whereas resistant models of other treatment groups were established according to similar protocols.These findings suggest that sequential passaging and drug exposure in PDX models recapitulated clinical tumor evolution,enabling the development of drug-resistant OSCC models.This study can offer methodological insights for precision therapy of OSCC.展开更多
We present a comprehensive extension of the integral of first passage times(IFS)method to investigate the adsorption kinetics of polymers with multiple binding sites on planar surfaces.While effective for single-point...We present a comprehensive extension of the integral of first passage times(IFS)method to investigate the adsorption kinetics of polymers with multiple binding sites on planar surfaces.While effective for single-point adsorption,the original IFS method was limited in capturing the complex kinetics of multi-point adsorption due to inadequate reaction coordinates and theoretical frameworks.Our approach introduces a center-of-mass-based reaction coordinate and a generalized kinetic model that accounts for multi-barrier free energy landscapes characteristic of collective polymer diffusion and binding.This theoretical advancement,implemented using the adaptive bias force method for efficient sampling,enables prediction of adsorption kinetics across timescales from nanoseconds to seconds.Our results demonstrate that adsorption behavior is governed by two key factors:the number of binding monomers primarily controls desorption barriers and long-term stability,while the configuration of pre-adsorbed layers significantly modulates both adsorption and desorption rates.Polymers with three or more binding sites exhibit effectively irreversible adsorption due to exponentially increasing desorption barriers,whereas different adsorbed layer configurations lead to distinct equilibrium coverages and kinetic profiles.This extended IFS framework provides critical insights for designing functional surfaces in nanoscale sensing,macromolecular recognition,and tailored polymeric coatings where precise control over adsorption kinetics is essential.展开更多
基金The National Basic Research Program Grant of China under contract No.2011CB403502the National High Technology Research and Development Program(863 Program)under contract No.2013AA09A506+2 种基金the Global Change and Air-Sea Interaction Program under contract No.GASI-03-01-01-04the International Cooperation Program Grant of China under contract No.2010DFB23580author Guan Yuping is supported by the National Natural Science Foundation of China under contract Nos 40976011 and 91228202
文摘The annual mean volume and heat transport sketches through the inter-basin passages and transoceanic sections have been constructed based on 1400-year spin up results of the MOM4p 1. The spin up starts from a state of rest, driven by the monthly climatological mean force from the NOAAWorld Ocean Atlas （1994）. The volume transport sketch reveals the northward transport throughout the Pacific and southward transport at all latitudes in the Atlantic. The annual mean strength of the Pacific-Arctic-Atlantic through flow is 0.63x106 m3/s in the Bering Strait. The majority of the northward volume transport in the southern Pacific turns into the Indonesian through flow （ITF） and joins the Indian Ocean equatorial current, which subse- quently flows out southward from the Mozambique Channel, with its majority superimposed on the Ant- arctic Circumpolar Current （ACC）. This anti-cyclonic circulation around Australia has a strength of 11 x 106 ms /s according to the model-produced result. The atmospheric fresh water transport, known as P-E^R （pre- cipitation minus evaporation plus runoff）, constructs a complement to the horizontal volume transport of the ocean. The annual mean heat transport sketch exhibits a northward heat transport in the Atlantic and poleward heat transport in the global ocean. The surface heat flux acts as a complement to the horizontal heat transport of the ocean. The climatological volume transports describe the most important features through the inter-basin passages and in the associated basins, including： the positive P-E＋R in the Arctic substantially strengthening the East Greenland Current in summer; semiannual variability of the volume transport in the Drake Passage and the southern Atlantic-Indian Ocean passage; and annual transport vari- ability of the ITF intensifying in the boreal summer. The climatological heat transports show heat storage in July and heat deficit in January in the Arctic; heat storage in January and heat deficit in July in the Antarctic circumpolar current regime （ACCR）; and intensified heat transport of the iTF in July. The volume transport of the ITF is synchronous with the volume transport through the southern Indo-Pacific sections, but the year-long southward heat transport of the ITF is out of phase with the heat transport through the equatorial Pacific, which is northward before May and southward after May. This clarifies the majority of the ITF origi- natinR from the southern Pacific Ocean.
基金Supported by the National Natural Science Foundation of China,No.81500207 to Xiao-Ting Liangand the Pyramid Talent Project,No.YQ677 to Yue Ding.
文摘This article discussed a study by Almahasneh et al,which investigated how high glucose and severe hypoxia affected mesenchymal stem cells(MSCs)at different passages.This research provides insights into the resilience of higher-passage MSCs under stress conditions,challenging the common use of lower passage MSCs in clinical settings.While this study offers valuable perspectives on the adaptability of MSCs,it relies mainly on in vitro results from a single cell line,limiting broader applicability.It highlights the need for more comprehensive in vivo studies to validate these findings and better understand MSC behavior in clinical scenarios.
文摘Pressure and proximity measurements made in a tunnel indicate that a typical vehicle passage produced on the tunnel roof an initial pressure increase of small magnitude,followed by a sharp and more substantial drop in pressure below atmospheric.The magnitude of the pressure drop was found to increase with smaller clearances between the vehicle top and the tunnel roof,consistent with the Bernoulli relation and the vehicle speed.The dynamic pressures potentially may have significant effects on the vibration and noise environments on the lower floors of“air rights construction”buildings that span highways.
基金Supported by the Deanship of Scientific Research,Yarmouk University,Jordan,No.73/2022.
文摘BACKGROUND Mesenchymal stem cells(MSCs)have been extensively studied for therapeutic potential,due to their regenerative and immunomodulatory properties.Serial passage and stress factors may affect the biological characteristics of MSCs,but the details of these effects have not been recognized yet.AIM To investigate the effects of stress factors(high glucose and severe hypoxia)on the biological characteristics of MSCs at different passages,in order to optimize the therapeutic applications of MSCs.METHODS In this study,we investigated the impact of two stress conditions;severe hypoxia and high glucose on human adipose-tissue derived MSCs(hAD-MSCs)at passages 6(P6),P8,and P10.Proliferation,senescence and apoptosis were evaluated measuring WST-1,senescence-associated beta-galactosidase,and annexin V,respectively.RESULTS Cells at P6 showed decreased proliferation and increased apoptosis under conditions of high glucose and hypoxia compared to control,while the extent of senescence did not change significantly under stress conditions.At P8 hAD-MSCs cultured in stress conditions had a significant decrease in proliferation and apoptosis and a significant increase in senescence compared to counterpart cells at P6.Cells cultured in high glucose at P10 had lower proliferation and higher senescence than their counterparts in the previous passage,while no change in apoptosis was observed.On the other hand,MSCs cultured under hypoxia showed decreased senescence,increased apoptosis and no significant change in proliferation when compared to the same conditions at P8.CONCLUSION These results indicate that stress factors had distinct effects on the biological processes of MSCs at different passages,and suggest that senescence may be a protective mechanism for MSCs to survive under stress conditions at higher passage numbers.
基金Natural Science Foundation of China(51806053)Anhui Provincial Key Research and Development Program(1804a09020012,1804a09020007)
文摘Elbow-inlet passage is widely used in large drainage pumping stations.Flow uniformity at the exit section directly determines its hydraulic performance.Flow uniformity must be optimized to improve the operational efficiency of the large axial-flow pumping station.Modeling and numerical simulation methods were used to investigate the elbow-inlet passage,and the accuracy of the calculation results was verified.The key geometric parameters affecting the uniformity of the flow were optimized by the orthogonal experiment design.The optimal schemes were obtained and compared with the original scheme.The results show that flow uniformity V u after optimization is 95.41%,which is increased by 1.04%.The pumping station efficiency is increased by 1.89%,thereby confirming the applicability and accuracy of the proposed scheme,especially for the optimization of flow uniformity of the exit section of the elbow-inlet passage.
基金the financial support of the Austrian Research Promotion Agency(FFG),Grant No.35863961。
文摘Since its outbreak in 2019,Severe Acute Respiratory Syndrome Coronavirus 2(SARS-Co V-2)keeps surprising the medical community by evolving diverse immune escape mutations in a rapid and effective manner.To gain deeper insight into mutation frequency and dynamics,we isolated ten ancestral strains of SARS-Co V-2 and performed consecutive serial incubation in ten replications in a suitable and common cell line and subsequently analysed them using RT-q PCR and whole genome sequencing.Along those lines we hoped to gain fundamental insights into the evolutionary capacity of SARS-Co V-2 in vitro.Our results identified a series of adaptive genetic changes,ranging from unique convergent substitutional mutations and hitherto undescribed insertions.The region coding for spike proved to be a mutational hotspot,evolving a number of mutational changes including the already known substitutions at positions S:484 and S:501.We discussed the evolution of all specific adaptations as well as possible reasons for the seemingly inhomogeneous potential of SARS-Co V-2 in the adaptation to cell culture.The combination of serial passage in vitro with whole genome sequencing uncovers the immense mutational potential of some SARS-Co V-2 strains.The observed genetic changes of SARS-Co V-2 in vitro could not be explained solely by selectively neutral mutations but possibly resulted from the action of directional selection accumulating favourable genetic changes in the evolving variants,along the path of increasing potency of the strain.Competition among a high number of quasi-species in the SARS-Co V-2 in vitro population gene pool may reinforce directional selection and boost the speed of evolutionary change.
基金Supported by the National Natural Science Foundation of China (Grant No. 30599434)the National Basic Research Program of China (Grant No. 2005CB523001)+1 种基金a grant from NIH (Grant No. 3U19AI051915-05S1)GFG is a distinguished young investigator of the NSFC (Grant No. 30525010)
文摘Although worldwide concern has been raised since the large-scale outbreak of highly pathogenic avian influenza in wild birds at Qinghai Lake,China in 2005,the factors responsible for the ability to kill waterfowl remain unclear. The why and how questions of the H5N1 virus species-jump into its reservoir host need to be answered. In this report we test the pathogenicity and adaptation of Qinghai Lake (Clade 2.2) isolate to Muscovy ducks for further understanding of this virus. The isolate was highly pathogenic in ducks and retained its high pathogenicity even after 20 generations of passage in ducks. During the process of serial passages,only the NS gene developed non-synonymous substitutions,which caused two mutations in NS1 protein (Val23Ala and Leu207Pro) and one in NS2 (Phe55Leu). These mutations persisted immutably through all subsequent passages and the pathogenicity remained high,implying that highly pathogenic H5N1 virus remains stable in aquatic birds through oral transmission. Although the exact functions of these mutations are not known,our results provide an important foundation for further understanding the characteristics of the Qinghai Lake isolates.
基金supported by the National Natural Science Foundation of China(Grant Nos.90921010 and 11174373)the National FundamentalResearch Program of China(Grant No.2010CB-923104)+1 种基金the National Research Foundation and Ministry of Education,Singapore(Grant No.WBS:R-710-000-008-271)the 2013 Doctoral Innovation funds of Southwes tJiaotong University and the Fundamental Research Funds for the Central Universities
文摘Quantum computation requires coherently controlling the evolutions of qubits.Usually,these manipulations are implemented by precisely designing the durations(such as theπ-pulses)of the Rabi oscillations and tunable interbit coupling.Relaxing this requirement,herein we show that the desired population transfers between the logic states can be deterministically realized(and thus quantum computation could be implemented)both adiabatically and non-adiabatically,by performing the duration-insensitive quantum manipulations.Our proposal is specifically demonstrated with the surface-state of electrons floating on the liquid helium,but could also be applied to the other artificially controllable systems for quantum computing.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFB-0905102).
文摘To better understand the characteristics of a large-scaled parabolic trough solar field(PTSF)under cloud passages,a novel method which combines a closed-loop thermal hydraulic model(CLTHM)and cloud vector(CV)is developed.Besides,the CLTHM is established and validated based on a pilot plant.Moreover,some key parameters which are used to characterize a typical PTSF and CV are presented for further simulation.Furthermore,two sets of results simulated by the CLTHM are compared and discussed.One set deals with cloud passages by the CV,while the other by the traditionally distributed weather stations(DWSs).Because of considering the solar irradiance distribution in a more detailed and realistically way,compared with the distributed weather station(DWS)simulation,all essential parameters,such as the total flowrate,flow distribution,outlet temperature,thermal and exergetic efficiency,and exergetic destruction tend to be more precise and smoother in the CV simulation.For example,for the runner outlet temperature,which is the most crucial parameter for a running PTSF,the maximum relative error reaches−15%in the comparison.In addition,the mechanism of thermal and hydraulic unbalance caused by cloud passages are explained based on the simulation.
基金Project supported by the National Natural Science Foundation of China (Grant No. 51406003)This work is accomplished by using the code RortexUTA and the code Omega-LiutexUTA which are released by Chaoqun Liu at University of Texas at Arlington.
文摘The complex vortex structures in the flow around turbine rotor passages, with weak or strong, large or small vortices, interacting with each other, often generate most of aerodynamic loss in turbomachines. Therefore, it is important to identify the vortex structures accurately for the flow field analysis and the aerodynamic performance optimization for turbomachines. In this paper, by using 4 vortex identification methods (the Q criterion, the Q method, the Liutex method and the Q -Liutex method), the vortices are identified in turbine rotor passages. In terms of the threshold selection, the results show that the D method and the Q -Liutex method are more robust, by which strong and weak vortices can be visualized simultaneously over a wide range of thresholds. As for the display consistency of the vortex identification methods and the streamlines, it is shown that the Liutex method gives results coinciding best with the streamlines in identifying strong vortices, while the Q -Liutex method gives results the most consistent with the streamlines in identifying weak vortices. As to the relationship among the loss, the vortices and the shear, except for the Q criterion, the other three methods can distinguish the vortical regions from the high shear regions. And the flow losses in turbine rotor passages are often related to high shear zones, while there is a small loss within the core of the vortex. In order to obtain the variation of vortices in the turbine rotor passages at different working points, the Liutex method is applied in 2 cases of a turbine with different angles of attack. The identification results show that the strengths of the tip leakage vortex and the upper passage vortex are weaker and the distance between them is closer at a negative angle of attack. This indicates that the Liutex method is an effective method, and can be used to analyze the vortex structures and their evolution in turbine rotor passages.
基金supported by the National Key R&D Program of China(2018YFB1307400).
文摘Path planning is a crucial concern in the field of mobile robotics,particularly in complex scenarios featuring narrow passages.Sampling-based planners,such as the widely utilized probabilistic roadmap(PRM),have been extensively employed in various robot applications.However,PRM’s utilization of random node sampling often results in disconnected graphs,posing a significant challenge when dealing with narrow passages.In order to tackle this issue,we present equipotential line sampling strategy for probabilistic roadmap(EPL-PRM),a novel approach derived from PRM.This paper initially proposes a sampling potential field,followed by the construction of equipotential lines that are denser in the proximity of obstacles and narrow passages.Random sampling is subsequently conducted along these lines.Consequently,the sampling strategy enhances the likelihood of sampling nodes around obstacles and narrow passages,thereby addressing the issue of sparsity encountered in traditional sampling-based planners.Furthermore,we introduce a nodal optimization method based on an artificial repulsive field,which prompts sampled nodes to move in the direction of repulsion.As a result,nodes around obstacles are distributed more uniformly,while nodes within narrow passages gravitate toward the middle of the passages.Finally,extensive simulations are conducted to evaluate the proposed method.The results demonstrate that our approach achieves path planning with superior efficiency,lower cost,and higher reliability compared with traditional algorithms.
基金supported by the National Key Research and Development Program of China(No.2018YFA0704600)。
文摘The wave rotor technology is an energy exchanging approach that achieves efficient energy transfer between gases without using mechanical components.The wave rotor technology has been successfully utilized in gas turbine cycle systems,gas expansion refrigeration and a variety of other industrial domains,yielding numerous researches and application outcomes.The structure of wave rotor passages inside which the energy exchange between gases is realized has an important impact on the equipment performance.In this study,based on gas wave ejection technology,the first application trials of an expansion wave rotor with curved passages were conducted.Additionally,the performance enhancing effect and mechanism of curved passages on the energy exchanging process were studied precisely by the combination of experimental and three-dimensional numerical simulation methods.The experimental results demonstrate that the curved passage rotor(CIR rotor)employed in this research has a maximum isentropic efficiency of 61.6%,and the CIR rotor achieves higher efficiency than the straight passage rotor(STR rotor)on all working conditions in this study.Compared with the STR rotor,the maximum efficiency improving ratio of CIR rotor can exceed 14.2%at each experimental expansion ratio,and the maximum relative increments of ejection rate are more than 5%.In addition,the CIR rotor can also effectively increase the proportion of static pressure in total pressure of the medium-pressure gas,and reduce the device power consumption.The three-dimensional numerical investigations revealed the principle of gas ejection in the wave rotors and explained why the CIR rotor performed better.According to the numerical findings,the curved passages of the CIR rotor may effectively minimize various energy losses created in the processes of high-pressure gas incidence,exhausting flow in nozzle,and high-speed gas flow in the passages.
文摘1Legal requirements The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.
文摘1Legal requirements.The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.
基金supported in part by the National Natural Science Foundation of China under Grant 62371181in part by the Changzhou Science and Technology International Cooperation Program under Grant CZ20230029The Institute of Information&Communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(No.RS-2024-00396797,Development of core technology for intelligent O-RAN security platform).
文摘Satellite communication technology has emerged as a key solution to address the challenges of data transmission in remote areas.By overcoming the limitations of traditional terrestrial communication networks,it enables long-distance data transmission anytime and anywhere,ensuring the timely and accurate delivery of water level data,which is particularly crucial for fishway water level monitoring.To enhance the effectiveness of fishway water level monitoring,this study proposes a multi-task learning model,AS-SOMTF,designed for real-time and comprehensive prediction.The model integrates auxiliary sequences with primary input sequences to capture complex relationships and dependencies,thereby improving representational capacity.In addition,a novel timeseries embedding algorithm,AS-SOM,is introduced,which combines generative inference and pooling operations to optimize prediction efficiency for long sequences.This innovation not only ensures the timely transmission of water level data but also enhances the accuracy of real-time monitoring.Compared with traditional models such as Transformer and Long Short-Term Memory(LSTM)networks,the proposed model achieves improvements of 3.8%and 1.4%in prediction accuracy,respectively.These advancements provide more precise technical support for water level forecasting and resource management in the Diqing Tibetan Autonomous Prefecture of the Lancang River,contributing to ecosystem protection and improved operational safety.
文摘Alice opened the door and found that it led into a small passage,not much larger than a rat⁃hole:she knelt down and looked along the passage into the loveliest garden you ever saw.How she longed to get out of that dark hall,and wander about among those beds of bright flowers and those cool fountains,but she could not even get her head through the doorway;“and even if my head would go through,”thought poor Alice,“it would be of very little use without my shoulders.Oh,how I wish I could shut up like a telescope!I think I could,if I only know how to begin.”For,you see,so many out⁃of⁃the⁃way things had happened lately,that Alice had begun to think that very few things indeed were really impossible.
文摘NEW MATTER MATTERS.Oriental Outlook.17 April.The Shenzhen-Zhongshan Link,a major cross-sea passage in Guangdong Province,stands as a testament to modern engineering.To meet the demands of its harsh marine environment,Chinese researchers have developed an advanced protective coating.Reinforced with ultrathin materials,this innovative solution is designed to extend the lifespan of steel structures well beyond a century by shielding them from corrosion.
基金National Natural Science Foundation of China,Grant/Award Number:82173399Young Elite Scientists Sponsorship Program by CAST,Grant/Award Number:2022QNRC001+2 种基金Beijing Natural Science Foundation,Grant/Award Number:7252096Beijing Natural Science Foundation-Haidian Original Innovation Joint Fund Project,Grant/Award Number:L222145CAMS&Comparative Medicine Center,PUMC (IACUC approval number:QC24002)
文摘Oral squamous cell carcinoma(OSCC)constitutes 90%of oral tumors.Advanced cases severely impair patients'life quality of life due to anatomical location and limited therapies.Conventional treatments often induce drug resistance or recurrence.Patientderived xenograft(PDX)models are widely used to simulate tumor progression and drug responses,serving as translational tools for precision medicine.This study aimed to establish drug-resistant OSCC PDX models.Human OSCC tissues were transplanted into immunodeficient mice and passaged(P1–P2).At P2(tumor volume:40–80 mm^(3)),mice received cisplatin(1 mg/kg,three times/week)with cetuximab(1 mg/kg,weekly),GSK690693(10 mg/kg,five times/week),or rapamycin(4 mg/kg,five times/week).PDX tissues from groups with less-therapeutic response(manifested as larger tumor volumes)were serially passaged to assess treatment efficacy.Tumor tissues with diminished drug sensitivity underwent histopathological analysis and identified stability of their tumor characteristics using hematoxylin–eosin(HE)and immunohistochemical staining after one additional passage and retreatment.Results demonstrated that successive passaging accelerates tumor growth.First-generation treatments showed universal sensitivity.At P2,cisplatin–cetuximab and rapamycin groups remained sensitive,whereas GSK690693 efficacy declined.Continued passaging of GSK690693-treated tumors confirmed resistance,as evidenced by exhibiting enhanced malignant characteristics at histological level.The GSK690693-resistant model was established first,whereas resistant models of other treatment groups were established according to similar protocols.These findings suggest that sequential passaging and drug exposure in PDX models recapitulated clinical tumor evolution,enabling the development of drug-resistant OSCC models.This study can offer methodological insights for precision therapy of OSCC.
基金financially supported by the National Natural Science Foundation of China(No.12374207)the Natural Science Foundation of Jiangsu Province(No.BK20233001)supported by the Big Data Computing Center of Southeast University。
文摘We present a comprehensive extension of the integral of first passage times(IFS)method to investigate the adsorption kinetics of polymers with multiple binding sites on planar surfaces.While effective for single-point adsorption,the original IFS method was limited in capturing the complex kinetics of multi-point adsorption due to inadequate reaction coordinates and theoretical frameworks.Our approach introduces a center-of-mass-based reaction coordinate and a generalized kinetic model that accounts for multi-barrier free energy landscapes characteristic of collective polymer diffusion and binding.This theoretical advancement,implemented using the adaptive bias force method for efficient sampling,enables prediction of adsorption kinetics across timescales from nanoseconds to seconds.Our results demonstrate that adsorption behavior is governed by two key factors:the number of binding monomers primarily controls desorption barriers and long-term stability,while the configuration of pre-adsorbed layers significantly modulates both adsorption and desorption rates.Polymers with three or more binding sites exhibit effectively irreversible adsorption due to exponentially increasing desorption barriers,whereas different adsorbed layer configurations lead to distinct equilibrium coverages and kinetic profiles.This extended IFS framework provides critical insights for designing functional surfaces in nanoscale sensing,macromolecular recognition,and tailored polymeric coatings where precise control over adsorption kinetics is essential.
