检索结果-南通市图书馆

An Impulsive Heating Model for the Evolution of Coronal Loops

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2006年第5期6卷 608-616页

作者： Li Feng wei-qun Gan Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 Max Planck Institute for Solar System Research Max-Planck-Str. 2 37191 Katlenburg-LindauGermany

It was suggested by Parker that the solar corona is heated by many small energy release events generally called microflares or nanoflares. More and more observations showed flows and intensity variations in nonflaring loops. Both theories and observations have indicated that the heating of coronal loops should actually be unsteady. Using SOLFTM （Solar Flux Tube Model）, we investigate the hydrodynamics of coronal loops undergoing different manners of impulsive heating with the same total energy deposition. The half length of the loops is 110 Mm, a typical length of active region loops. We divide the loops into two categories： loops that experience catastrophic cooling and loops that do not. It is found that when the nanoflare heating sources are in the coronal part, the loops are in non-catastrophic-cooling state and their evolutions are similar. When the heating is localized below the transition region, the loops evolve in quite different ways. It is shown that with increasing number of heating pulses and inter-pulse time, the catastrophic cooling is weakened, delayed, or even disappears altogether.

关键词： hydrodynamics -- Sun corona -- Sun transition region

Relationship between LTP and the nuclear protein induced by calcineurin

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第16期43卷 1384-1387页

作者： Jie Luo qun wei Beijing Normal Univ Dept Biol Biochem & Mol Biol Lab Beijing 100875 Peoples R China

Results demonstrate that calcineurin plays a role in long term potentiation (LTP) in the hippocampus. A 45 ku enzyme was administered, which exhibits Ca 2+/calmodulin independent activity to rats, and the protein components of nuclear extracts from the cell-free system of rat hippocampus were tested. It is found that the level of a component significantly increased in nuclear extracts following the activation of calcineurin. The concentration of the component in the nucleus is also markedly increased following hippocampal LTP elicited by ginsenosides. These results suggest that the activation of calcineurin induces a pre-existing protein component to translocate to the nucleus in the hippocampus. The nuclear translocation of the component may be required for LTP in the hippocampus.

关键词： calcineurin nuclear protein learning and memory long-term potentiation (LTP).

Synthesis and morphology of triangular pyramid-shaped puerarin microparticle with nanostructure

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2010年第4期21卷 484-487页

作者： Lu, Chuan Hua Zhang, qun wei Anhui Coll Tradit Chinese Med Sch Pharm Hefei 230038 Peoples R China

A type of triangular pyramid-shaped microparticles of puerarin was synthesized by using oil-in-oil microemulsion approach which is simple and economical under the action of copper *** pyramid-shaped microparticles would be made up of deposit of nanospheres or nanorods and have two significant *** is its complex surface morphology like coral *** other is a lot of nanopores in existence in the microparticle *** possible formation routes were speculated.

关键词： Triangular pyramid-shaped puerarin microparticles Synthesis Nanosphere Nanorod

Low frequency repetitive transcranial magnetic stimulation improves motor dysfunction after cerebral infarction

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2017年第4期12卷 610-613页

作者： Zhi-yong Meng wei-qun Song Department of Rehabilitation Xuanwu HospitalCapital Medical University

Low frequency （≤ 1 Hz） repetitive transcranial magnetic stimulation （rTMS） can affect the excitability of the cerebral cortex and synaptic plasticity. Although this is a common method for clinical treatment of cerebral infarction, whether it promotes the recovery of motor function remains controversial. Twenty patients with cerebral infarction combined with hemiparalysis were equally and randomly divided into a low frequency rTMS group and a control group. The patients in the low frequency rTMS group were given 1-Hz rTMS to the contralateral primary motor cortex with a stimulus intensity of 90% motor threshold, 30 minutes/day. The patients in the control group were given sham stimulation. After 14 days of treatment, clinical function scores （National Institute of Health Stroke Scale, Barthel Index, and Fugl-Meyer Assessment） improved significantly in the low frequency rTMS group, and the effects were better than that in the control group. We conclude that low frequency （1 Hz） rTMS for 14 days can help improve motor function after cerebral infarction.

关键词： nerve regeneration brain injury repetitive transcranial magnetic stimulation motor dysfunction cerebral infarction NationalInstitute of Health Stroke Scale Barthel Index Fugl-Meyer Assessment neural regeneration

Multi-wavelength Diagnostics of Bombardment by Non-thermal Particles in Solar Flares

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2005年第5期5卷 519-530页

作者： Zhi Xu Cheng Fang wei-qun Gan Astronomy Department of Nanjing University Nanjing 210093 Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008

Chromospheric lines, including Ha, Lya, Lyβ and CaⅡ K, CaⅡ 8542, are systemically and quantitatively investigated with respect to the non-thermal excitation and ionization due to particle beam bombardment for a series of solar semi-empirical atmospheric models. As a result we propose to use the contrast in the integrated intensity of hydrogen lines to estimate the total energy flux of the bombarding beam during the solar flare impulsive phase. Partial frequency redistribution is considered in the Lyα line calculation and a smaller intensity en- hancement in the Hα line-centers is found than in the previous results of Fang et al.

关键词： Sun: flare- Sun: chromosphere

A combined DFT and molecular dynamics study of U(Ⅵ)/calcite interaction in aqueous solution

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2017年第15期62卷 1064-1073页

作者： Jian-Hui Lan Zhi-Fang Chai wei-qun Shi Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China School of Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions Soochow University Suzhou 215123 China

Here we present a combined DFF and molecular dynamics study of uranyl （U（VI）） interaction mecha- nisms with the calcite （104） surface in aqueous solution. The roles of three anion ligands （CO2 , HCO3, OH ） and solvation effect in U（VI） interaction with calcite have been evaluated. According to our calculations, water adsorbed on the calcite （104） surface prefers to exist in molecular state rather than dis- sociative state. Energy analysis indicate that the positively charged uranyl species prefers to form surface complexes on the surface, while neutral uranyl species may bind with the surface via both surface complexing and ion exchange reactions of U（VI） → Ca（II）. In contrast, the negatively charged uranyl species prefer to interact with the surface via ion exchange reactions of U（VI）→ Ca（II）, and the one with UO2（CO3）2（H2O）^2- as the reactant becomes the most favorable one in energy. We also found that uranyl adsorption increases the hydrophilicability of the （104） surface to different extents, where the UO2（CO3）3Ca2 species contributes to the largest degree of energy changes （ 53 kcal/mol）. Our calcula- tions proved that the （104） surface also has the ability to immobilize U（VI） via either surface complexing or ion exchange mechanisms under different pH values.

关键词： Uranyl Incorporation Adsorption Calcite Density functional theory Molecular dynamics

Mode-I-crack compression modeling and numerical simulation for evaluation of in-situ stress around advancing coal workfaces

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2009年第5期19卷 569-573页

作者： LIU wei-qun ZHU Li School of Sciences China University of Mining ＆ Technology Xuzhou Jiangsu 221116 China University of California Berkeley CA94720 USA

The relatively high stress probably leads to generation of a fractured or even instable area around a working coalface. Also, the generated weak area often evolves into an easy-infiltrating field of water/gas to greatly increase probability of accident occurrence. To reveal the distribution of high stress around working faces, we put forward the mode-I-crack compression model. In this model, the goaf following a working face is regarded as a mode-I crack in an infinite plate, and the self-gravity of overlaying strata is transformed into an uniform pressure applied normal to the upper edge of the model crack. Solving this problem is based on the Westergaard complex stress function. For comparison, the software RFPA-2D is also employed to simulate the same mining problem, and furthermore extendedly to calculate the stress interference induced by the simultaneous advances of two different working faces. The results show that, the area close to a working face or the goaf tail has the maximum stress, and the stress is distributed directly proportional to the square root of the advance and inversely proportional to the square root of the distance to the working face. The simultaneous advances of two neighboring working faces in different horizontals can lead to extremely high resultant stress in an interference area.

关键词： mode-I-crack modeling Westergaard stress function working face high stress stress interference

Activities and properties of calcineurin catalytic domain

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第15期45卷 1394-1399页

作者： Yang Shujie Zhang Li wei qun Department of Biochemistry and Molecular Biology Beijing Normal UniversityBeijing 100875China State Key Laboratory of Biomacromolecules Institute of BiophysicsChinese Academy of SciencesBeijing 100101China

Calcineurin (CN) is the only protein phosphatase known to be under the control of calcium (Ca2+) and calmodulin (CaM). The enzyme consists of two subunits, the catalytic A subunit of 61 ku (CNA) and a regulatory B subunit of 19 ku (CNB). In this study, we used PCR amplication to construct a truncation consisting of only the CNA catalytic domain. The truncation was induced by IPTG and expressed in E. coli. PNPP was used as a substrate to study the phosphatase activity of the CNA catalytic domain. The findings show that its activity is 20 times greater than CNA in the presence of CNB and CaM. The optimum reaction temperature for the CNA catalytic domain protein is 40℃, and the optimum reaction pH value is 8.0. Mn2+ is still an effective activator for the CNA catalytic domain, but its activity is not controlled by Ca2+. In the presence of 6 mmol/L Mg2+, adding either Ca2+ or EGTA did not change the activity of the CNA catalytic domain.

关键词： calcineurin protein phosphatase catalytic domain activity enzyme property.

Inherited cardiomyopathies caused by troponin mutations

在线全文

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2013年第1期10卷 91-101页

作者： qun-wei Lu Xiao-Yan Wu Sachio Morimoto Key Laboratory of Molecular Biophysics of Ministry of Education College of Life Science and Technology Center for Human Genome Research Huazhong University of Science and Technology Wuhan 430074 China Department of Pediatrics Union Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430022 China Department of Clinical Pharmacology Graduate School of Medical Sciences Kyushu University Fukuoka 812-8582 Japan

Genetic investigations of cardiomyopathy in the recent two decades have revealed a large number of mutations in the genes encoding sarcomeric proteins as a cause of inherited hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), or restrictive cardiomyopathy (RCM). Most functional analyses of the effects of mutations on cardiac muscle contraction have revealed significant changes in the Ca2+-regulatory mechanism, in which cardiac troponin (cTn) plays important structural and functional roles as a key regulatory protein. Over a hundred mutations have been identified in all three subunits of cTn, i.e., cardiac troponins T, I, and C. Recent studies on cTn mutations have provided plenty of evidence that HCM- and RCM-linked mutations increase cardiac myofilament Ca2+ sensitivity, while DCM-linked mutations decrease it. This review focuses on the functional consequences of mutations found in cTn in terms of cardiac myofilament Ca2+ sensitivity, ATPase activity, force generation, and cardiac troponin I phosphorylation, to understand potential molecular and cellular pathogenic mechanisms of the three types of inherited cardiomyopathy.

关键词： Calcium sensitivity Cardiomyopathy Muscle contraction Troponin