检索结果-南通市图书馆

Communications in Theoretical Physics 2006年第5X期46卷 843-844页

作者： LAI Mei-Mei WANG xin XIAO Yan-ping liu Quan-Hui School for Theoretical Physics and Department of Applied Physics Hunan University Changsha 410082 China

When the motion of a particle is constrained, excess terms exist using hermitian form of Cartesian momentum pi （i=1, 2,3） in usual kinetic energy （1/2/μ）∑ pi^2 , and the correct kinetic energy turns out to be （1/2μ） ∑1/ fipi f ipi, where fi are dummy factors in classical mechanics and nontrivial in quantum mechanics. In this paper the explicit form of the dummy functions fi is given for a charged rigid planar rotator in the uniform magnetic field with different gauge chosen. Under different gauges, we have different sets of dummy factors. It means that these factors do not have direct observable effect.

关键词： operator ordering gauge transformation quantum mechanics

Cloning of the kininogen gene from Lampetra japonica provides insights into its phylogeny in vertebrates

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2009年第2期36卷 109-115页

作者： Liwei Zhou xin liu ping Jin Qingwei Li College of Life Sciences Liaoning Normal University Dalian 116029 China

Kininogens, the precursors of bradykinins, ubiquitously exist in vertebrates, including mammals, birds, amphibians, and fishes. To elucidate the phylogeny of kininogen genes in early vertebrates, we cloned the full-length cDNA of kininogen gene from the liver of Lampetra japonica. The open reading frame of this sequence contained 546 bp and encoded 181 amino acids, including a cystatin domain without the canonical binding site for cysteine proteinases and a bradykinin domain. Our results suggested that in lampreys and most of other vertebrates, there might be only one kininogen gene, which was fused by certain sequences during vertebrate evolution and encoded proteins with more functions; however, another special kininogen gene, only encoding the bradykinin domain with multiple copies in some species, arose only in amphibians for adapting themselves to the unique environment. Using reverse transcription PCR, kininogen mRNA was also detected in lamprey gut, kidney, and leukocyte, but absent in lamprey buccal gland. Our findings may provide insights into the phylogeny of kininogen genes as well as other gene families in vertebrates.

关键词： kininogen Lampetrajaponica phylogeny bradykinin domain cystatin domain tissue distribution

Immunolocalization assessment of metastasis-associated protein I in human and mouse mature testes and its association with spermatogenesis

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2007年第3期9卷 345-352页

作者： Wei Li xin-ping liu Ruo-Jun Xu Yuan-Qiang Zhang Department of Histology and Embryology The Fourth Military Medical University Xi＇an 710032 China Department of Biochemistry and Molecular Biology The Fourth Military Medical University Xi＇an 710032 China Department of Zoology University of Hong Kong Hong Kong China

Aim： To investigate the stage-specific localization of metastasis-associated protein 1 （MTA1） during spermatogenesis in adult human and mouse testis. Methods： The immunolocalization of MTA1 was studied by immunohistochemistry and Western blot analysis. The distribution pattern of MTA1 in mouse testis was confirmed by using quantitative analysis of purified spermatogenic cells. Results： The specificity of polyclonal antibody was confirmed by Western blot analysis. MTA1 was found expressed in the nucleus of germ cells, except elongate spermatids, and in the cytoplasm of Sertoli cells; Leydig cells did not show any specific reactivity. MTA1 possessed different distribution patterns in the two species： in humans, the most intensive staining was found in the nucleus of round spermatids and of primary spermatocytes while in mice, the most intense MTA 1 staining was in the nucleus of leptotene, zygotene and pachytene spermatocytes. In both species the staining exhibited a cyclic pattern. Conclusion： The present communication initially provides new evidence for the potential role of MTA1 in mature testis. In addition, its distinctive expression in germ cells suggests a regulatory role of the peptide during spermatogenesis.

关键词： human metastasis-associated proteinl mouse metastasis-associated protein 1 spermatogenesis nuclear remodeling anddeacetylation complex chromatin remodeling spermiogenesis deacetylation

Characteristics of deep drainage and soil water in the mobile sandy lands of Inner Mongolia, northern China

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

Journal of Arid Land 2015年第2期7卷 238-250页

作者： xin ping liu Yu Hui HE Xue Yong ZHAO Tong Hui ZHANG La Mei ZHANG Yun Hua MA Shu Xia YAO Shao Kun WANG Shui Lian WEI Naiman Desertification Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Laboratory of Stress Ecophysiology and Biotechnology Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Quantification of deep drainage and the response of soil water content to rainfall patterns are critical for an effective management strategy of soil water conservation and groundwater utilization. However, there has been little information on how rainfall characteristics influence soil water dynamics and deep drainage in mobile sandy lands. We used an underground chamber to examine the responses of deep drainage and soil water content in mobile sandy lands to rainfall characteristics in Inner Mongolia during the growing seasons of 2010, 2011 and 2012. Results showed that rainfall in this area was dominated by small events （〈5 mm）, which increased soil water con- tent in the surface soil layers （0-40 cm）, but did not increase soil water content in the deeper soil layers （greater than 40 cm）. Soil water content at the 0-100 cm depth increased significantly when the total amount of rain was 〉20 mm. Rainfall amount, intensity and the duration of dry intervals were significantly related to the soil water content in different soil layers. Deep drainage was significantly correlated with rainfall amount and intensity, but not with the duration of dry intervals. The coefficients of deep drainage in the mobile sandy lands ranged from 61.30% to 67.94% during the growing seasons. Our results suggested that rainfall infiltration in the mobile sandy lands had considerable potential to increase soil water storage while recharging the groundwater in this region.

关键词： mobile sandy lands rainfall characteristics deep drainage soil water content

Comparison of the major malformation rate of children conceived from cryopreserved embryos and fresh embryos

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2010年第14期123卷 1893-1897页

作者： LI Hong-zhen QIAO Jie CHI Hong-bin CHEN xin-na liu ping MA Cai-hong Medical Center -for Human Reproduction Department of Obstetrics and Gynecology Peking University Third Hospital Beijing 100191 China

Background Cryopreserved embryo transfer has become indispensable in reproductive technology. More and more children are conceived from frozen-thawed embryo transfer （FET）. The risk of birth defects associated with frozen-thawed embryo transfer has been evaluated and conflict results are obtained. The aim of this study was to compare the rate of major malformations in children conceived from cryopreserved embryos with that of children from fresh embryos. Methods A retrospective analysis was performed on children conceived from frozen-thawed embryos and fresh embryos between January 2005 and December 2008 at the Reproduction Center of the Third Hospital, Peking University. The major malformation rates were compared between two groups for all children, as welt as singletons or twins, separately. The frequencies of different subtypes of malformations classified according to different organ system were also compared. Results Thirty-four of 3125 children from cryopreserved embryos had a major malformation. The malformation rate was 1.09%, which was comparable to that for children after fresh embryos transfer （1.53%（55/3604）, OR： 0.71, 95%Cl; 0.46-1.09）. The malformation rate was also similar when the analysis was limited to children from cryopreserved embryos resulted from in vitro fertilization （IVF）（1.39%）and fresh IVF（1.3%）. However, children from cryopreserved embryos resulted from intracytoplasmic sperm injections （ICSI） had much lower malformation rate than from fresh ICS1（0.63% vs.1.83%, OR： 0.34, 95% CI： 0.16-0.75）. No difference was found in the incidence of major malformations in singletons from cryo ICSI （0.73%） and fresh ICS1（1.9%）, or from cryo IVF（1.49%） and fresh IVF（1.67%）. Similar malformation rate was found in multiples from cryo ICS1（0.52%） and fresh ICS1（1.76%）, or cryo IVF（1.30%） and fresh IVF（0.90%）. The distribution and risk of the subtype of malformations, such as cardiovascular, gastrointestinal, neural tube, urogenital, musculoskeletal and facia

关键词： congenital malformation fertilization in vitro sperm injections, intracytoplasmic frozen-thawed embryo transfer

Significant role of carbonate radicals in tetracycline hydrochloride degradation based on solar light-driven TiO2-seashell composites:Removal and transformation pathways

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2020年第10期41卷 1511-1521页

作者： Jiaqi Wang Qingrong Qian Qinghua Chen xin-ping liu Yongjin Luo Hun Xue Zhaohui Li College of Environmental Science and Engineering Fujian Key Laboratory of Pollution Control&Resource ReuseFujian Normal UniversityFuzhou 350007FujianChina Fuqing Branch of Fujian Normal University Fuqing 350300FujianChina State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350116FujianChina

TiO2-seashell composites prepared via a sol-gel method were used to generate carbonate radicals(·CO3–) under solar light irradiation. ·CO3–, a selective radical, was employed to degrade the target tetracycline hydrochloride contaminant. A series of characterizations was carried out to study the structure and composition of the synthesized TiO2-seashell composite. This material exhibits excellent solar light-driven photochemical activity in the decomposition of tetracycline hydrochloride. The possible pathway and mechanism for the photodegradation process were proposed on the basis of high-resolution electrospray ionization time-of-flight mass spectrometry experiments. Finally, we investigated the reusability of the TiO2-seashell composite. This study is expected to provide a new facile pathway for the application of ·CO3– radicals to degrade special organic pollutants in water.

关键词： TiO2-seashell Carbonate radical Photochemistry Tetracycline hydrochloride Mechanism

Research status and prospects of the fractal analysis of metal material surfaces and interfaces

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 20-38页

作者： Qinjin Dai Xuefeng liu xin Ma Shaojie Tian Qinghe Cui Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Laboratory for Advanced Materials Processing of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Mechanical and Electrical Engineering Xinjiang Institute of EngineeringUrumqi 830023China

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine *** analysis has been used to characterize the shapes of metal materials at various scales and *** methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and ***,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal *** the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear *** relationship between the fractal dimensions and properties of metal material surfaces and interfaces is *** from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be *** is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

关键词： metal material surfaces and interfaces fractal analysis fractal dimension homogeneity

Estimation of Chloride Diffusivity in Hydrated Tricalcium Silicate Using a Hydration-Diffusion Integrated Method

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 49-64页

作者： WANG xin SHEN Dejian TAO Sijie liu Ruixin WU Shengxing College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China

This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydration simulation,thermodynamic calculation,and finite element analysis to examine the effects of pore solution,including effect of electrochemical potential,effect of chemical activity,and effect of mechanical interactions between ions,on the chloride effective diffusion coefficient of hydrated C3S *** results indicate that the effect of electrochemical potential on chloride diffusion becomes stronger with increasing hydration age due to the increase in the content of hydrated calcium silicate;as the hydration age increases,the effect of chemical activity on chloride diffusion weakens when the number of diffusible elements decreases;the effect of mechanical interactions between ions on chloride diffusion decreases with the increase of hydration age.

关键词： tricalcium silicate simulation method chloride diffusion coefficient pore solution

UPLC Orbitrap HRMS法分析西洋参蒸参弃液浓缩物中皂苷类成分

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

质谱学报 2017年第1期38卷 52-59页

作者：张勇黄鑫李帅坪刘淑莹长春中医药大学吉林省人参科学研究院吉林长春130117 中国科学院长春应用化学研究所长春质谱中心吉林长春130022

采用超高效液相色谱-四极杆静电场轨道阱高分辨质谱(UPLC Orbitrap HRMS)技术测定西洋参蒸参弃液浓缩物中15种人参皂苷单体成分含量。采用Thermo Scientific Syncronis C18色谱柱(100mm×2.1mm×1.7μm),以乙腈-0.1%甲酸水溶液为流动相... 详细信息

采用超高效液相色谱-四极杆静电场轨道阱高分辨质谱(UPLC Orbitrap HRMS)技术测定西洋参蒸参弃液浓缩物中15种人参皂苷单体成分含量。采用Thermo Scientific Syncronis C18色谱柱(100mm×2.1mm×1.7μm),以乙腈-0.1%甲酸水溶液为流动相,使用电喷雾电离源(ESI),四极杆静电场轨道阱质量分析器,高分辨质谱仪采集数据。结果表明,人参皂苷Rg1、Rg2、Rg3、Rb1、Rb2、Rc、Rd、Re、Rh1、Rh2、Rk1、Ro、F1、F2和伪人参皂苷F11在线性范围内均存在良好的线性关系,48h内稳定性实验RSD值均小于5%,平均加样回收率为94.38%~102.10%,RSD值不大于3%。西洋鲜参在不同蒸制温度和蒸制时间下得到9组蒸参弃液,通过分析其浓缩物中15种人参皂苷单体化合物的含量,并比较各成分含量的变化情况,总结了4种类型人参皂苷的化学转化规律。该方法简便、准确、灵敏度高、专属性强、重复性好,适用于西洋参蒸参弃液浓缩物中皂苷成分含量的测定,可为开发蒸参弃液提供有效的检测手段。

关键词：超高效液相色谱-四极杆静电场轨道阱高分辨质谱(UPLC Orbitrap HRMS) 西洋参蒸参弃液人参皂苷

Comparative proteomic analysis of plasma exosomes reveals the functional contribution of N-acetyl-alpha-glucosaminidase to Parkinson’s disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第10期20卷 2998-3012页

作者： Yuan Zhao Yidan Zhang xin liu Jian Zhang Ya Gao Shuyue Li Cui Chang Xiang liu Guofeng Yang Department of Geriatrics Second Hospital of Hebei Medical UniversityShijiazhuangHebei ProvinceChina Department of Neurosurgery The Second Hospital of Hebei Medical UniversityShijiazhuangHebei ProvinceChina

Parkinson’s disease is the second most common progressive neurodegenerative disorder,and few reliable biomarkers are available to track disease *** proteins,DNA,mRNA,and lipids carried by exosomes reflect intracellular changes,and thus can serve as biomarkers for a variety of *** this study,we investigated alterations in the protein content of plasma exosomes derived from patients with Parkinson’s disease and the potential therapeutic roles of these proteins in Parkinson’s *** a tandem mass tag-based quantitative proteomics approach,we characterized the proteomes of plasma exosomes derived from individual patients,identified exosomal protein signatures specific to patients with Parkinson’s disease,and identified N-acetyl-alpha-glucosaminidase as a differentially expressed protein.N-acetyl-alpha-glucosaminidase expression levels in exosomes from the plasma of patients and healthy controls were validated by enzyme-linked immunosorbent assay and western *** results demonstrated that the exosomal N-acetyl-alpha-glucosaminidase concentration was not only lower in Parkinson’s disease,but also decreased with increasing Hoehn-Yahr stage,suggesting that N-acetyl-alpha-glucosaminidase could be used to rapidly evaluate Parkinson’s disease ***,western blot and immunohistochemistry analysis showed that N-acetyl-alpha-glucosaminidase levels were markedly reduced both in cells treated with 1-methyl-4-phenylpyridinium and cells overexpressingα-synuclein compared with control ***,N-acetyl-alpha-glucosaminidase overexpression significantly increased cell viability and inhibitedα-synuclein expression in 1-methyl-4-phenylpyridinium-treated *** together,our findings demonstrate for the first time that exosomal N-acetyl-alpha-glucosaminidase may serve as a biomarker for Parkinson’s disease diagnosis,and that N-acetyl-alpha-glucosaminidase may reduceα-synuclein expression and 1-methyl-4-phenylpyridinium-induced n

关键词： biomarker diagnosis exosomes N-acetyl-alpha-glucosaminidase Parkinson’s disease proteomic α-synuclein