检索结果-南通市图书馆

Preventive effect of a pectic polysaccharide of the common cranberry vaccinium oxycoccos L. on acetic acid-induced colitis in mice

引用

World Journal of Gastroenterology 2006年第41期12卷 6646-6651页

作者： Sergey v Popov Pavel A Markov Ida R Nikitina Sergey Petrishev vasily smirnov Yury S Ovodov Department of Molecular Immunology and Biotechnology Institute of PhysiologyKomi Science CentreThe Urals Branch of the Russian Academy of Sciences50 Pervomaiskaya str.Syktyvkar 167982Russia

AIM： To study isolation and chemical characterization of pectin derived from the common cranberry vaccin/um oxycoccos L. （oxycoccusan OP） and the testing of its preventive effect on experimental colitis. METHODS： Mice were administrated orally with OP two days prior to a rectal injection of 5% acetic acid and examined for colonic damage 24 h later. Colonic inflammation was characterized by macroscopical injury and enhanced levels of myeloperoxidase activity measured spectrophotometrically with o-phenylene diamine as the substrate. The mucus contents of the colon were determined by the Alcian blue dye binding method. vascular permeability was estimated using 4% Evans blue passage after i.p. injection of 0.05 mol/L acetic acid. RESULTS： In the mice treated with OP, colonic macroscopic scores （1.1 ± 0.4 vs 2.7, P 〈 0.01） and the total square area of damage （10 ± 2 vs 21 ± 7, P 〈 0.01） were significantly reduced when compared with the vehicle-treated colitis group. OP was shown to decrease the tissue myeloperoxidase activity in colons （42 ± 11 vs 112 ± 40, P 〈 0.01） and enhance the amount of mucus of colitis mice （0.9 ± 0.1 vs 0.4 ± 0.1, P 〈 0.01）. The level of colonic malondialdehyde was noted to decrease in OP-pretreated mice （3.6 ± 0.7 vs 5.1 ± 0.8, P 〈 0.01）. OP was found to decrease the inflammatory status of mice as was determined by reduction of vascular permeability （161 ± 34 vs 241 ± 21, P 〈 0.01）. Adhesion of peritoneal neutrophils and macrophages was also shown to decrease after administration of OP （141 ± 50 vs 235 ± 37, P 〈 0.05）. CONCLUSION： Thus, a preventive effect of pectin from the common cranberry, namely oxycoccusan OP, on acetic acid-induced colitis in mice was detected. A reduction of neutrophil infiltration and antioxidant action may be implicated in the protective effect of oxycoccusan.

关键词： Common cranberry vaccinium oxycoccos L Pectin Colitis Anti-inflammatory Mice

来源：

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

Synergistic effect of chitin nanofibers and polyacrylamide on electrochemical performance of their ternary composite with polypyrrole

引用

Journal of Energy Chemistry 2018年第3期27卷 843-853页

作者： Michael A.smirnov Maria P.Sokolova Natalya v.Bobrova Alexander M.Toikka Pierfrancesco Morganti Erkki Lahderanta Lappeenranta University of Technology 53850 LappeenrantaFinland Institute of Macromolecular compounds Russian Academy of Sciences199004 Saint PetersburgRussia St.Petersburg State University PeterhofSaint Petersburg 198504Russia Dermatological Institute II University of Naples80138 NaplesItaly

Development of simple methods for preparation of polymeric electrode materials with nanofibrous network structure is a perspective way toward cheap supercapacitors with high specific capacitance and energy density. In this work one-pot synthesis of electroactive ternary composite based on polypyrrole, polyacrylamide and chitin nanofibers with beneficial morphology was elaborated. Ternary system demonstrates better electrochemical performance in comparison with both polypyrrole–polyacrylamide and polypyrrole–chitin binary composites. Possible mechanism of synergistic effect of simultaneous influence of polyacrylamide and chitin nanofibers on the formation of composite＇s structure is *** highest attained specific capacitance of electroactive polypyrrole in ternary composite reached 249 F/g at 0.5 A/g and 150 F/g at 32 A/g. Symmetrical supercapacitor was assembled using the elaborated electrode material. High specific capacitance 89 F/g and good cycling stability with capacitance retention of 90% after 3000 cycles at 2 A/g were measured.

关键词： Energy materials Nanocomposites Natural fibers Electrical properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Population dynamics of Amur tigers(Panthera tigris altaica)in Sikhote-Alin Biosphere Zapovednik:1966–2012

引用

Integrative Zoology 2015年第4期10卷 315-328页

作者： Dale G.MIQUELLE Evgeny N.smirnov Olga Yu.ZAUMYSLOvA Svetlana v.SOUTYRINA Douglas H.JOHNSON Wildlife Conservation Society BronxNew YorkUSA Sikhote-Alin Biosphere Zapovednik TerneiPrimorskii KraiRussia USGS Northern Prairie Wildlife Research Center Saint PaulMinnesotaUSA

In 2010,the world’s tiger(Panthera tigris)range countries agreed to the goal of doubling tiger numbers over 12 years,but whether such an increase is biologically feasible has not been ***-term monitoring of tigers in Sikhote-Alin Biosphere Zapovednik(SABZ),Russia provided an opportunity to determine growth rates of a recovering population.A 41-year growth phase was followed by a rapid decline in tiger *** growth rates during the growth phase averaged 4.6%,beginning near 10%in the earliest years but quickly dropping below 5%.Sex ratio(females per male)mirrored growth rates,declining as population size *** rapid decline from 2009 to 2012 appeared to be tied to multiple factors,including poaching,severe winters and *** indicators of this population are similar to those of Bengal tiger populations,suggesting that growth rates may be *** results suggest that,first,tiger populations likely in general grow slowly:3–5%yearly increases are realistic and larger growth rates are likely only when populations are highly depressed,mortality rates are low and prey populations are high relative to numbers of adult ***,while more research is needed,it should not be assumed that tiger populations with high prey densities will necessarily grow more quickly than populations with low prey ***,while growth is slow,decline can be ***,because declines can happen so quickly,there is a constant need to monitor populations and be ready to respond with appropriate and timely conservation interventions if tiger populations are to remain ***,an average annual growth rate across all tiger populations of 6%,required to reach the Global Tiger Initiative’s goal of doubling tiger numbers in 12 years,is a noble but unlikely scenario.

关键词： Amur tiger growth rates population dynamics

来源：

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

Titanium oxide artificial synaptic device:Nanostructure modeling and synthesis,memristive cross-bar fabrication,and resistive switching investigation

引用

Nano Research 2023年第7期16卷 10222-10233页

作者： vadim I.Avilov Roman v.Tominov Zakhar E.vakulov Lev G.Zhavoronkov vladimir A.smirnov Research Laboratory Neuroelectronics and Memristive Nanomaterials(NEUROMENA Lab) Southern Federal UniversityTaganrog 347922Russia Institute of Nanotechnologies Electronics and Electronic Equipment EngineeringSouthern Federal UniversityTaganrog 347922Russia

The paper shows the results of the mathematical model development and the numerical simulation of the oxygen vacancies,and the distribution of TiO,Ti_(2)O_(3),and TiO_(2)oxides in the titanium oxide nanostructure obtained by local anodic oxidation(anodization).The effect of the anodization voltage pulse duration and amplitude on the titanium oxide composition distribution and the conduction channel formation was *** device prototypes based on electrochemical titanium oxide are fabricated and *** was shown that forming free resistive switching between the low resistances state(LRS)1.43±0.54 kΩand the high resistance state(HRS)28.75±9.75 kΩwere observed during 100,000 switching cycles and LRS 1.49±0.23 kΩwas maintained for 10,000 *** resistive switching of the synaptic device prototype was *** was shown that increasing Uset from 0.5 to 1.5 v leads to different LRS from 3.96±0.19 to 0.71±0.10 kΩ.The results obtained can be used in the development of technological foundations for the formation of high-performance multilevel artificial synapses for elements of neuroelectronics and hardware neural networks.

关键词： artificial intelligence neuromorphic systems memristive cross bar resistive switching scanning probe microscopy titanium oxide

来源：

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

基于Q级联理论估算同位素生产的成本

引用

原子能科学技术 2020年第4期54卷 761-768页

作者：曾实余欢雷增光 BORISEvICH v D smirnov A Yu SULABERIDZE G A 清华大学工程物理系北京100084 中国核工业集团有限公司北京100822 National Research Nuclear University MEPhI Moscow 115409Russia

在决定某种同位素的生产之前,有必要进行生产的经济性分析,以了解和确保生产的经济可行性。本文给出一种用离心法生产非铀同位素的成本分析方法。利用Q模型级联(简称Q级联)理论得到同位素分离的原料利用率与级联相对总流量的关系。通过... 详细信息

在决定某种同位素的生产之前,有必要进行生产的经济性分析,以了解和确保生产的经济可行性。本文给出一种用离心法生产非铀同位素的成本分析方法。利用Q模型级联(简称Q级联)理论得到同位素分离的原料利用率与级联相对总流量的关系。通过利用公开的离心法铀同位素分离的单位分离功价格数据,避免生产成本分析中涉及分离单元成本和人员成本等多个复杂因素,在假定分离部分成本正比于分离工厂规模情况下,导出了成本分析的简单公式,可根据原料成本、铀单位分离功价格、原料利用率等对产品成本进行评估和优化。并以铅同位素208Pb的生产为例,对成本分析的过程进行了阐述。结果表明:利用本文的方法,成本分析简单易行。

关键词：同位素分离 Q级联生产成本分析

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Urea Preparation by Oxidative Carbonylation of Ammonia

引用

Journal of Environmental Science and Engineering 2011年第8期5卷 1006-1012页

作者： A.R. Elman v.I. smirnov Rostkhim Ltd. Moscow 105118 Russia

Effective one-stage method of urea preparation by catalytic oxidative carbonylation of ammonia in liquid phase is developed. The method allows to prepare urea with productivity of-530 g/（L·h） in sufficiently mild conditions （total pressure -30 bar, 45 ℃）. The process is characterized by high selectivity （near 100%） i.e. byproducts separation is not needed. Almost all CO is consumed during the process, this substantially diminishes the waste-gas purification costs and raises the process environmental characteristics; the only byproduct is water.

关键词： Urea ammonia oxidative carbonylation selenium heat efficiency

来源：

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

Travel time prediction with viscoelastic traffic model

引用

Applied Mathematics and Mechanics(English Edition) 2018年第12期39卷 1769-1788页

作者： Yongliang ZHANG M.N.smirnovA A.I.BOGDANOvA Zuojin ZHU N.N.smirnov Faculty of Engineering Science University of Science and Technology of China Faculty of Mechanics and Mathematics Moscow M.V.Lomonosov State University Scientific Research Institute for System Analysis Russian Academy of Sciences

Travel time through a ring road with a total length of 80 km has been predicted by a viscoelastic traffic model(vEM), which is developed in analogous to the non-Newtonian fluid flow. The vEM expresses a traffic pressure for the unfree flow case by space headway, ensuring that the pressure can be determined by the assumption that the relevant second critical sound speed is exactly equal to the disturbance propagation speed determined by the free flow speed and the braking distance measured by the average vehicular length. The vEM assumes that the sound speed for the free flow case depends on the traffic density in some specific aspects, which ensures that it is exactly identical to the free flow speed on an empty road. To make a comparison, the open Navier-Stokes type model developed by Zhang(ZHANG, H. M. Driver memory, traffic viscosity and a viscous vehicular traffic flow model. Transp. Res. Part B, 37, 27–41(2003)) is adopted to predict the travel time through the ring road for providing the counterpart *** the traffic free flow speed is 80 km/h, the braking distance is supposed to be 45 m,with the jam density uniquely determined by the average length of vehicles l ≈ 5.8 m. To avoid possible singular points in travel time prediction, a distinguishing period for time averaging is pre-assigned to be 7.5 minutes. It is found that the travel time increases monotonically with the initial traffic density on the ring road. Without ramp effects, for the ring road with the initial density less than the second critical density, the travel time can be simply predicted by using the equilibrium speed. However, this simpler approach is unavailable for scenarios over the second critical.

关键词： travel time viscoelastic modeling distinguishing period for time averaging spatial-temporal pattern traffic jam

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Boundary Eigenvalue Problem for Maxwell Equations in a Nonlinear Dielectric Layer

引用

Applied Mathematics 2010年第1期1卷 29-36页

作者： Yury G. smirnov Dmitry v. valovik Department Mathematics and Supercomputer Modeling Penza State University Penza Russia

The propagation of TM-polarized electromagnetic waves in a dielectric layer filled with lossless, nonmagnetic, and isotropic medium is considered. The permittivity in the layer defines by Kerr law. We look for eigenvalues of the problem and reduce the issue to the analysis of the corresponding dispersion equation. The equivalence of the boundary eigenvalue problem and the dispersion equation is proved. We show that the solution of the problem exists and from dispersion equation it can be numerically obtained. Using this solution the components of electromagnetic field in the layer can be numerically obtained as well. Transition to the limit in the case of a linear medium in the layer is proved. Some numerical results are presented also.

关键词： Maxwell Equations Nonlinear Boundary Eigenvalue Problem Dispersion Equation Nonlinear Slab (Film)

来源：

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

Problems of Birds Sex Determination

引用

Natural Science 2014年第15期6卷 1232-1240页

作者： Antonina v. Trukhina Aleksandr F. smirnov Department of Genetics and Biotechnology St. Petersburg State University St. Petersburg Russia

Sex determination system in birds is characterized by a homo-(Neognatae) and heteromorphic (Paleognatae) sex chromosomes. Heterogametic sex is female (ZZ/ZW system). DMRT1 gene is a gene regarded as a main male sex determining factor in this group of animals. The question remains about the participation of other factors (HEMOGEN, AMH etc.) in appearance of testis, and the role of steroid hormones in formation of ovaries. Complete sex inversion is not typical for species with genotypic sex determination (GSD), although the effect of estrogen metabolites is noted for birds. For birds epigenetic mechanisms of regulation (methylation of DNA and non-coding RNA) have been described for sex controlling genes such as CYP19A1 and DMRT1.

关键词： Bird Sex Determination Epigenetics Dosage Compensation

来源：

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

Experimental Sex Inversion of Chicken Embryos at Aromatase Inhibition, Estrogen Receptor Modulation, DNA Demethylation and Progesterone Treatment

引用

Natural Science 2016年第11期8卷 451-459页

作者： Antonina v. Trukhina Natalia A. Lukina Aleksandr F. smirnov Department of Genetics and Biotechnology St. Petersburg State University St. Petersburg Russia

The work was carried out by microinjections of an aromatase inhibitor letrozole, an estrogen receptor modulator tamoxifen in incubated eggs Gallus g. domesticus, the first day of incubation. It also used 5-azacytidine (5-AC) at the same time. Injection of progesterone was carried out before the onset of meiosis prophase 1 on 16 h of incubation. Morphologically and histologically and by PCR, sex of the 17-day embryos was controlled. According to information received microinjection of letrozole caused almost a 100% inversion of genetic males to females, which is manifested in the morphology of the gonads. In other experiments, sex reversal is not revealed. The results are obtained in this study, and the data suggest that the presence of gonadogenesis in female chickens makes earlier emergence of aromatase in the beginning of incubation, than that according to the classical scheme of sex determination in birds. Presumably this kind of synthesis is triggered by some W-chromosomal factors. It failed to detect the phenomenon of gender inversion—the transformation of males into females after exposure to demethylating agent 5-AC that casts doubt on the participation of male hypermethylated (MHM)-RNA-segment in regulating the activity of sex determining genes.

关键词： Gallus gallus Sex Determination Aromatase Gonad DMRT1

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：