检索结果-南通市图书馆

Effects of calcineurin on LTP of rats in vivo

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第6期47卷 476-479页

作者： luo Jie LOU Ailin WEI qun Department of Biochemistry and Molecular Biology Beijing Normal UniversityBeijing 100875China Department of Physiology Institute of Clinical Medical Sciences China-Japan Friendship HospitalBeijing 100020China

Calcineurin (CN) is thought to play a role in the synaptic plastivity and long-term potentiation (LTP) in the hippocampus. Based on two LTP models in vivo, a specific inhibitor cyclosporin A (CsA) of CN was observed, which affected LTP in the hippocampal dentate gyrus of the rats. The results indicated that CsA blocked LTP induced by high frequency stimulation (HFS) partly, but it had no effect on the decrease of the onset and peak latency of population spikes (PS) except that it reduced the increase of the amplitude after HFS. On the other hand, CsA blocked LTP induced by ginsenosides (GSS) completely. It suppressed the GSS-enhanced amplitude of PS reversibly and blocked the decrease of the peak latency of PS induced by the GSS. These results suggest that the postsynaptic CN plays a role in the induction of LTP in the hippocampus of the rats.

关键词： calcineurin cyclosporin A hippocampus long term po-tentiation (LTP) ginsenosides.

Normalized solutions for a fourth-order Schrődinger equation with a positive second-order dispersion coefficient

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2023年第6期66卷 1237-1262页

作者： xiao luo Tao Yang School of Mathematics Hefei University of TechnologyHefei 230009China Department of Mathematics Zhejiang Normal UniversityJinhua 321004China

In this paper,we study normalized solutions to a fourth-order Schrődinger equation with a positive second-order dispersion coefficient in the mass supercritical *** the well-studied case where the second-order term is zero or negative,the geometrical structure of the corresponding energy functional changes dramatically and this makes the solution set *** suitable control of the second-order dispersion coefficient and mass,we find at least two radial normalized solutions,a ground state and an excited state,together with some asymptotic *** is worth pointing out that in the considered repulsive case,the compactness analysis of the related Palais-Smale sequences becomes more *** forces the implementation of refined estimates of the Lagrange multiplier and the energy level to obtain normalized solutions.

关键词： fourth-order Schrodinger equation mixed dispersion normalized solution variational method

Regression Analysis of Doubly Censored Data with a Cured Subgroup under a Class of Promotion Time Cure Models

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2021年第6期37卷 835-853页

作者： Min CAI Li qun xiao Shu Wei LI School of Economics and Statistics Guangzhou UniversityGuangzhou 510006P.R.China

In some situations,the failure time of interest is defined as the gap time between two related events and the observations on both event times can suffer either right or interval *** data are usually referred to as doubly censored data and frequently encountered in many clinical and observational ***,there may also exist a cured subgroup in the whole population,which means that not every individual under study will experience the failure time of interest *** this paper,we consider regression analysis of doubly censored data with a cured subgroup under a wide class of flexible transformation cure ***,we consider marginal likelihood estimation and develop a two-step approach by combining the multiple imputation and a new expectation-maximization(EM)algorithm for its *** resulting estimators are shown to be consistent and asymptotically *** finite sample performance of the proposed method is investigated through simulation *** proposed method is also applied to a real dataset arising from an AIDS cohort study for illustration.

关键词： Doubly censored data marginal likelihood EM algorithm multiple imputation transformation cure models

Study on the passive film formed on 2205 stainless steel in acetic acid by AAS and XPS

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 170-176页

作者： Xue-qun Cheng xiao-gang Li Chao-fang Dong Corrosion and Protection Center University of Science and Technology Beijing Beijing 100083 China

The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry （AAS）, X-ray photoelectron spectroscopy （XPS）, and electrochemical polarization measurements. AAS results show that molybdenum is enriched on the surface as the passive film is dissolved. This enrichment decreases the corrosion resistance because it hinders chloride adsorption and Fe ion dissolution, and acts as a local pH buffer because it consumes protons. The dissolution ratio of Fe/Cr is approximately 10 during the active dissolution of the passive film. XPS results indicate that when the potential is in the passivation region, Cr comprises about 50% of the metal cations in the near-surface region of the passive film and is the main metal constituent in this region. When the polarization potential is much greater than the transpassivation potential, the Mo content accounts for approximately 45% of the metal cations in the nearurface region; Fe and Ni have no obvious influence on the formation, dissolution, or puncture of the passive film.

关键词： acetic acid corrosion electrochemical behavior stainless steel passive film

凡纳对虾parkin共调基因和parkin在抗白斑综合征病毒中的表达分析和SNP开发

在线全文

学校读者我要写书评

暂无评论

渔业科学进展 2025年第1期46卷 194-209页

作者：薛倩李旭鹏李洋栾生罗坤孔杰邢群孟宪红浙江海洋大学水产学院浙江舟山316021 海水养殖生物育种与可持续产出全国重点实验室中国水产科学研究院黄海水产研究所山东青岛266071 青岛海洋科技中心海洋渔业科学与食物产出过程功能实验室山东青岛266237 邦普种业科技有限公司山东潍坊261311

本实验室前期研究中基于全基因组关联分析(GWAS)方法筛选到抗白斑综合征病毒(WSSV)候选基因:parkin共调基因(PACRG)。PACRG与帕金森病相关基因parkin共用一个双向启动子,二者共同参与细胞自噬过程,从而在细胞保护方面发挥作用。本研究... 详细信息

本实验室前期研究中基于全基因组关联分析(GWAS)方法筛选到抗白斑综合征病毒(WSSV)候选基因:parkin共调基因(PACRG)。PACRG与帕金森病相关基因parkin共用一个双向启动子,二者共同参与细胞自噬过程,从而在细胞保护方面发挥作用。本研究对凡纳对虾(Penaeus vannamei)PACRG和parkin在抗WSSV中的功能进行探讨,对其mRNA和氨基酸序列进行特征分析,利用real-timePCR技术检测对虾感染WSSV后不同时间、不同组织中PACRG和parkin的表达水平。通过荧光原位杂交技术(FISH)进行空间定位。利用PCR和Sanger测序技术获得单核苷酸多态性位点(SNP)并进行抗WSSV的关联分析。结果显示,PACRG开放阅读框(ORF)全长600bp,编码199个氨基酸,预测包含一个ParcG结构域。parkinORF序列全长1653bp,编码550个氨基酸,预测包含UBQ、IBR结构域和一个信号肽结构。与多物种进行同源序列比对发现,凡纳对虾PACRG氨基酸序列与日本对虾(Penaeus japonicus)的同源性高达89.70%;凡纳对虾parkin氨基酸序列与中国对虾(Penaeus chinensis)和斑节对虾(Penaeus monodon)的同源性高达93.45%。PACRG和parkin蛋白的保守性较高。感染WSSV后,PACRG和parkin在对虾肝胰腺、鳃、肌肉和眼柄中的表达水平发生显著变化,其中,眼柄中PACRG和parkin表现出极相似的组织表达模式。在肌肉中,PACRGmRNA和WSSV在空间位置上呈现高度重叠状态。结合上述结果,推测PACRG和parkin在凡纳对虾与WSSV的互作中发挥功能。在PACRG中筛选到2个SNP位点,在parkin中筛选到15个SNP位点,其中位于parkin非翻译区(UTR)的5个SNP位点与抗WSSV性状显著相关。本文为研究凡纳对虾抗WSSV的分子机制和抗病分子育种提供了理论依据和参考数据。

关键词：凡纳对虾白斑综合征病毒(WSSV) parkin共调基因(PACRG) parkin基因 SNP

Meta label associated loss for fine-grained visual recognition

同方期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第6期67卷 230-247页

作者： Yanchao LI Fu xiao Hao LI qun LI Shui YU School of Computer Science Nanjing University of Posts and Telecommunications School of Network Engineering Zhoukou Normal University School of Computer Science University of Technology Sydney

Recently, intensive attempts have been made to design robust models for fine-grained visual recognition, most notably are the impressive gains for training with noisy labels by incorporating a reweighting strategy into a meta-learning framework. However, it is limited to up or downweighting the contribution of an instance for label reweighting approaches in the learning process. To solve this issue, a novel noise-tolerant method with auxiliary web data is proposed. Specifically, first, the associations made from embeddings of well-labeled data with those of web data and back at the same class are measured. Next, its association probability is employed as a weighting fusion strategy into angular margin-based loss, which makes the trained model robust to noisy datasets. To reduce the influence of the gap between the well-labeled and noisy web data, a bridge schema is proposed via the corresponding loss that encourages the learned embeddings to be coherent. Lastly, the formulation is encapsulated into the meta-learning framework, which can reduce the overfitting of models and learn the network parameters to be noise-tolerant. Extensive experiments are performed on benchmark datasets, and the results clearly show the superiority of the proposed method over existing state-of-the-art approaches.

关键词： label associated loss weighting noisy samples fine-grained visual recognition noise-tolerant learning meta-learning

Linear operators and positive semidefiniteness of symmetric tensor spaces

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2015年第1期58卷 197-212页

作者： luo Zi Yan QI Li qun YE Yin Yu State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Department of Applied Mathematics The Hong Kong Polytechnic University Department of Management Science and Engineering Stanford University

We study symmetric tensor spaces and cones arising from polynomial optimization and physical *** prove a decomposition invariance theorem for linear operators over the symmetric tensor space,which leads to several other interesting properties in symmetric tensor *** then consider the positive semidefiniteness of linear operators which deduces the convexity of the Frobenius norm function of a symmetric ***,we characterize the symmetric positive semidefinite tensor(SDT)cone by employing the properties of linear operators,design some face structures of its dual cone,and analyze its relationship to many other tensor *** particular,we show that the cone is self-dual if and only if the polynomial is quadratic,give specific characterizations of tensors that are in the primal cone but not in the dual for higher order cases,and develop a complete relationship map among the tensor cones appeared in the literature.

关键词： symmetric tensor symmetric positive semidefinite tensor cone linear operator SOS cone

Crystallization and dielectric properties of lead-free glass-ceramic composites with Gd_2O_3 addition

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2012年第3期31卷 281-284页

作者： Zhou, Yi Zhang, Qingmeng luo, Jun Tang, qun Du, Jun Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China

Lead-free glass-ceramic composites in barium sodium niobate silica system with Gd2O3 addition were synthesized through melt-casting fol-lowed by controlled crystallization technique. Crystallization and dielectric properties of the Gd2O3 adding glass-ceramic composites were investigated. With the increase in the concentration of Gd2O3, the glass transition temperature and the crystallization temperature of the pre-cursor glass shift towards the higher temperature. The crystallization behavior that occurred during the heat treatment procedure leads to the enhancement of dielectric constant. All the three compositions of glass-ceramic composites exhibit ferroelectricity when tested at room tem-perature. Both the values of the remanent polarization and coercive field are enhanced regularly with the gradual increase in the concentration of Gd2O3 additive under the same testing field.

关键词： Gd2O3 addition glass-ceramic composites crystallization dielectric properties ferroelectricity

On the Shadowing Property and Shadowable Point of Set-valued Dynamical Systems

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2020年第12期36卷 1384-1394页

作者： xiao Fang luo xiao xiao NIE Jian Dong YIN Department of Mathematics Nanchang UniversityNanchang 330031P.R.China

In this article,the authors introduce the concept of shadowable points for set-valued dynamical systems,the pointwise version of the shadowing property,and prove that a set-valued dynamical system has the shadowing property iff every point in the phase space is shadowable;every chain transitive set-valued dynamical system has either the shadowing property or no shadowable points;and for a set-valued dynamical system there exists a shadowable point iff there exists a minimal shadowable *** the end,it is proved that a set-valued dynamical system with the shadowing property is totally transitive iff it is mixing and iff it has the specification property.

关键词： Shadowing property shadowable point set-valued dynamical system specification