检索结果-南通市图书馆

Downregulation of Col lal induces differentiation in mouse spermatogonia

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2012年第6期14卷 842-849页

作者： Sun-hong chen Ding li chen Xu Department of Histology and Embryology Shanghai Jiao Tong University School of Medicine Shanghai Key Laboratory of Reproductive Medicine Shanghai 200025 China

Col la I （one of the subunit of collagen type I） is a collagen, which belongs to a family of extracellular matrix （ECM） proteins that play an important role in cellular proliferation and differentiation. However, the role of Col lal in spermatogenesis, especially in the control of proliferation and differentiation of spermatogonial stem cells （SSCs）, remains unknown. In this study, we explored effects of downregulation of Collal on differentiation and proliferation of mouse spermatogonia. Loss-of-function study revealed that Oct4 and Plzf, markers of SSC self-renewal, were significantly decreased, whereas the expression of c-kit and haprin, hallmarks of SSC differentiation, was enhanced after Col la I knockdown. Cell cycle analyses indicated that two-thirds of spermatogonia were arrested in S phase after Collal knockdown. In vivo experiments, DNA injection and electroporation of the testes showed that spermatogonia self-renewal ability was impaired remarkably with the loss-of-function of Collal. Our data suggest that silencing of Collal can suppress spermatogonia self-renewal and promote spermatogonia differentiation.

关键词： Collal differentiation extracellular matrix (ECM) spermatogenesis spermatogonia

Graphene-tuned threshold gain to achieve optical pulling force on microparticle

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 306-310页

作者： hong-li chen Yang Huang School of Science Nantong UniversityNantong 226019China School of Science Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and TechnologyJiangnan UniversityWuxi 214122China

We investigate optical force on a graphene-coated gain microparticle by adopting the Maxwell's stress tensor *** is found that there exists a threshold gain in obtaining the Fano-profile optical force which indicates the reversal of optical pushing and pulling force. And giant pushing/pulling force can be achieved if the gain value of the material is in the proximity of the threshold gain. Our results show that the threshold gain is more sensitive to the relaxation time than to the Fermi energy of the graphene. We further study the optical force on larger microparticle to demonstrate the pulling force occurring at octupole resonance with small gain value and then it will appear at quadrupole resonance by increasing gain value. Our work provides an in-depth insight into the interaction between light and gain material and gives the additional degree of freedom to optical manipulation of microparticle.

关键词： pulling force threshold gain graphene microparticle

On the rate of convergence for multi-category classification based on convex losses

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2007年第11期50卷 1529-1536页

作者： hong chen Luo-qing li Faculty of Mathematics and Computer Science Hubei UniversityWuhan 430062China Faculty of Mathematics and Computer ScienceHubei UniversityWuhan 430062China

The multi-category classification algorithms play an important role in both theory and practice of machine *** this paper,we consider an approach to the multi-category classification based on minimizing a convex surrogate of the nonstandard misclassification *** bound the excess misclassification error by the excess convex *** construct an adaptive procedure to search the classifier and furthermore obtain its convergence rate to the Bayes rule.

关键词： misclassiflcation error consistency convergence rate

Development of a subchannel code for blockage accidents of LMFRs based on the 3D fuel rod model

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2022年第3期33卷 30-44页

作者： Xiao Luo lian-Kai Cao Wen-Pei Feng hong-li chen School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China

To predict the thermal-hydraulic(T/H)parameters of the reactor core for liquid-metal-cooled fast reactors(LMFRs),especially under flow blockage accidents,we developed a subchannel code called *** code uses a time-dependent,four-equation,singlephase flow model together with a 3D heat conduction model for the fuel rods,which is solved by numerical methods based on the finite difference method with a staggered *** to the local effect of the blockage on the flow field,low axial flow,increased forced crossflow,and backflow *** more accurately simulate this problem,we implemented a robust and novel solution *** verified the code with a low-flow(~0.01 m/s)and large-scale blockage *** the preliminary validation,we compared our results with the experimental data of the NACIE-UP BFPS blockage test and the KIT19ROD blockage *** results revealed that KMC-FB has sufficient solution accuracy and can be used in future flow blockage analyses for LMFRs.

关键词： Subchannel method Code development Blockage accident liquid-metal-cooled fast reactor

Startup scheme optimization and flow instability of natural circulation lead-cooled fast reactor SNCLFR-100

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2021年第11期32卷 191-200页

作者： Wen-Shun Duan Ze-Ren Zou Xiao Luo hong-li chen School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China

Owing to the inherent instability of the natural circulation system,flow instability can easily occur during the operation of a natural circulation lead-cooled fast reactor,especially during the startup phase.A comprehensive startup scheme for SNCLFR-100,including primary and secondary circuits,is proposed in this *** references existing more mature startup schemes in various reactor *** additionally considers the restriction conditions on the power increase in other schemes and the characteristics of lead-based *** this basis,the multi-scale coupling code ATHLET-OpenFOAM was used to study the flow instability in the startup phase under different power-step amplitudes and power duration *** results showed that obvious flow instability phenomena were found in the different startup schemes,such as the short-term backflow phenomenon of the core at the initial time of the ***,an obvious increase in the flow rate and temperature to the peak value at the later stage of a continuous power rise was observed,as well as continuous oscillations before reaching a steady *** was determined that the scheme with smaller power-step amplitude and a longer power duration time requires more time to start the ***,it will be more conducive to the safe and stable startup of the reactor.

关键词： Natural circulation Lead-cooled fast reactor Startup scheme Flow instability Multi-scale coupling

Development and validation of a new oxide fuel rod performance analysis code for the liquid metal fast reactor

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2022年第5期33卷 167-177页

作者： Guang-liang Yang Hai-Long liao Tao Ding hong-li chen School of Nuclear Science and Technology University of Science and Technology of ChinaHefei230026China

The integrity and reliability of fuel rods under both normal and accidental operating conditions are of great importance for nuclear *** this study,considering various irradiation behaviors,a fuel rod performance analysis code,named KMC-Fueltra,was developed to evaluate the thermal–mechanical performance of oxide fuel rods under both normal and transient conditions in the *** accuracy and reliability of the KMC-Fueltra were validated by analytical solutions,as well as the results obtained from codes and *** results indicated that KMC-Fueltra can predict the performance of oxide fuel rods under both normal and transient conditions in the LMFR.

关键词： Fuel rod analysis code Thermal-mechanical performance Irradiation behaviors Pellet-cladding mechanical interaction liquid metal fast reactor

Switch-on fluorescence sensor for ascorbic acid detection based on MoS2 quantum dots-MnO2 nanosheets system and its application in fruit samples

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2017年第2期28卷 338-344页

作者： Ya-li Xu Xiao-Ying Niu hong-li chen Sheng-Guo Zhao Xing-Guo chen State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringKey Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu ProvinceLanzhou UniversityLanzhou 730000China Gansu Entry-Exit Inspection and Quarantine Bureau Lanzhou 730020China

In this work,molybdenum disulfide quantum dots（MoS2 QDs） were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid *** joining MnO2 nanosheets into MoS2 QDs solution,they produced an obvious fluorescence quenching,which should be due to inner filter effect（IFE）.Meanwhile,the fluorescent probe was formed,Interestingly,we found that this quenching phenomenon disappeared with the addition of ascorbic acid,In other words,the fluorescence gradually *** recovery phenomenon is mainly due to the reduction effect of ascorbic acid for MnO2 *** the optimum conditions,the limit of detection（LOD） of 39 nmol/L for ascorbic acid was achieved with a linear range of 0.33-5.00 μmol/*** repeatability was better than 5.0% for ascorbic acid in both standard and fruit samples（n = 3）.Moreover,the as-fabricated fluorescent sensing system was successfully employed to detect the ascorbic acid levels in hawthorn and jujube with satisfactory results.

关键词： MoS2 QDs MnO2 nanosheets Ascorbic acid "Switch-on" fluorescence sensor Fruit samples

Biosensor Based on TTF@SiO_2 Nanoparticles as Electron Transfer Mediator for the Determination of Glucose

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第4期22卷 474-478页

作者： li Xiao-hua XIAN Yue-zhong MIN hong li chen-xin XIE Zong-hong ZHANG Fen-fen JIN li-tong Department of Chemistry East China Normal University Shanghai 200062 P. R. China

Tetrathiafulvalene（TTF） was doped in an SiO2 network and the resulting nanocompesite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica（TIT@SiO2 ） nanoparticles were prepared by the water-in-oil（W/O） microemulsion method, and were characterized by transmission electron microscopy（TEM）. The core-shell structure TTF@ SiO2 could prevent TIT from leaching out into an aqueous solution. Combined with chitosan （CHIT）, which serves as a scaffold for glucose oxidase and nanocomposite immobilization, the GCE/TTF@ SiO2- CHIT-GOx biosensor was developed. Under optimal conditions, the biosensors exhibit a linear range of 1.0 × 10^-5 5 × 10^-3 mol/L with a detection limit down to 5.0 μmol/L（S/N = 3 ）. The excellent selectivity, sensitivity, and stability of the glucose biosensor show its potential for practical applications.

关键词： TTF@ SiO2 nanoparticle Chitosan Glucose Biosensor

GENERAliZATION PERFORMANCE OF MULTI-CATEGORY KERNEL MACHINES——In Memory of Professor Sun Yongsheng

在线全文

学校读者我要写书评

暂无评论

Analysis in Theory and Applications 2007年第2期23卷 188-195页

作者： hong chen Luoqing li Faculty of Mathematics and Computer Science Hubei University Wuhan 430062 E R. China

Support vector machines are originally designed for binary classification. How to effectively extend it for multi-class classification is still an on-going research issue. In this paper, we consider kernel machines which are natural extensions of multi-category support vector machines originally proposed by Crammer and Singer. Based on the algorithm stability, we obtain the generalization error bounds for the kernel machines proposed in the paper.

关键词： Kernel machine uniform stability generalization error