检索结果-南通市图书馆

Chinese Journal of Structural Chemistry 1995年第2期14卷 145-150页

作者：谢秀兰 Augstin,lo StateKeyLaboratoryofStructuralChemistryandFujianIn StateKeyLaboratoryofStructura

Magnetic susceptibility of a series of dinuclear Ⅴ(Ⅳ) . Co(Ⅱ) and Mn(Ⅲ) complexes has been measured in the temperature range of 1. 5 ～300K. The isotropic Heisenberg theory has been applied to study the temperature-dependent behaviour of the magnetic susceptibility of these complexes and a corresponding program for fitting the experimental results has been set up on a VAX 11/785 computer. Conclusions can be drawn that the three complexes studied are all anti-ferromagnetically coupled with coupling constants -4. 4 , -115. 2 , and - 8. 4 cm￣(-1) for Ⅴ(Ⅳ) . Co(Ⅱ) ,and Mn(Ⅲ) complexes, respectively.

关键词： magnetic susceptibility magnetic exchange interaction anti-ferromagnetic coupling isotropic Heisenberg model theoretical fitting

Effect of natural organic matter on thallium and silver speciation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2020年第7期32卷 185-192页

作者： loïc A.Martin Caroline Simonucci Sétareh Rad Marc F.Benedetti Universitéde Paris Institut de physique du globe de ParisCNRSF-75005 ParisFrance IRSN PSE-ENV/SIRSE/LER-NordBP 1792262 Fontenay-aux-Roses CedexFrance Catchment and Eco-Hydrology Research Group Luxembourg Institute of Science and TechnologyL-4422 BelvauxLuxembourg BRGM Unitéde Géomicrobiologie et Monitoring Environnemental45060 Orléans Cedex 2France

Natural organic matter(NOM)is known to play an important role in the transport and binding of trace metal elements in aquatic and soil *** is a pollutant for which the extent of the role played by NOM is poorly ***,this study investigates thallium(Ⅰ)and its complexation to a purified humic substance as proxy for *** were performed with the Donnan Membrane Technique to separate,for the first time,the free Tl^+ion from its complexed form in the bulk *** pH and concentrations were investigated at constant ionic strength and constant NOM proxy concentrations in *** results were described with NICA-Donnan *** complexation was compared to silver complexation using literature data and using the same NICA-Donnan *** for these two cations(Tl^+and Ag^+)are reported in this article,for the first *** display low thallium complexation to the NOM proxy while silver competes with divalent cations for the NOM binding *** speciation for dissolved thallium highlights the dominance of free thallium(Tl^+)in solution whereas Tl-NOM complexes contribute roughly 15%to total Tl(Ⅰ)species in river and lake type *** results are obtained for soil solutions,Tl-bound to NOMse and geochemistry.

关键词： Thallium Organic matter Speciation NICA-Donnan model Soil Water

Cellular, physiological and pathological aspects of the long non-coding RNA NEAT1

在线全文

学校读者我要写书评

暂无评论

Frontiers in Biology 2016年第6期11卷 413-426页

作者： Pang-Kuo lo Benjamin Wolfson Qun Zhou Department of Biochemistry and Molecular Biology Greenebaum Cancer Center University of Maryland School of Medicine BaltimoreMD 21201 USA

BACKGROUND： The majority of mammalian genomes have been found to be transcribed into non-coding RNAs. One category of non-coding RNAs is classified as long non-coding RNAs （lncRNAs） based on their transcript sizes larger than 200 nucleotides. Growing evidence has shown that lncRNAs are not junk transcripts and play regulatory roles in multiple aspects of biological processes. Dysregulation of lncRNA expression has also been linked to diseases, in particular cancer. Therefore, studies of lncRNAs have attracted significant interest in the field of medical research. Nuclear enriched abundant transcript 1 （NEAT1）, a nuclear lncRNA, has recently emerged as a key regulator involved in various cellular processes, physiological responses, developmental processes, and disease development and progression. OBJECTIVE： This review will summarize and discuss the most recent findings with regard to the roles of NEAT1 in the function of the nuclear paraspeckle, cellular pathways, and physiological responses and processes. Particularly, the most recently reported studies regarding the pathological roles of deregulated NEAT1 in cancer are highlighted in this review. METHODS： We performed a systematic literature search using the Pubmed search engine. Studies published over the past 8 years （between January 2009 and August 2016） were the sources of literature review. The following keywords were used：＂Nuclear enriched abundant transcript 1,＂＂NEATI,＂ and ＂paraspeckles.＂ RESULTS： The Pubmed search identified 34 articles related to the topic of the review. Among the identified literature, 13 articles report findings related to cellular functions of NEAT1 and eight articles are the investigations of physiological functions of NEAT1. The remaining 13 articles are studies of the roles of NEAT1 in cancers. CONCLUSION： Recent advances in NEAT1 studies reveal the multifimctional roles of NEAT1 in various biological processes, which are beyond its role in nuclear paraspeckles. Recent studies al

关键词： long non-coding RNAs (lncRNAs) nuclear enriched abundant transcript 1 (NEAT1) paraspeckles microRNAs(miRNAs) epigenetic regulation cancer

Is there a relationship between length of resection and lymph-node ratio in colorectal cancer?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Gastroenterology Report 2021年第3期9卷 234-240,I0002页

作者： Antonio Zanghi Andrea Cavallaro Emanuele lo Menzo serena Curella Botta Salvatore lo Bianco Maria Di Vita Francesco Cardi Alessandro Cappellani General and Breast Surgery Unit Department of SurgeryUniversity of CataniaCataniaItaly Department of General Surgery Digestive Disease InstituteCleveland Clinic FloridaWestonFLUSA

Background:The prognosis of colorectal cancer depends on the number of positive lymph nodes(LNþ)and the total number of lymph nodes resected(rLN).This represents the lymph-node ratio(LNR).The aim of our study is to assess how the length of the resected specimen(RL)influences the prognostic values of the ***:We conducted a retrospective study of all the patients operated on for colorectal cancer from 2000 to 2015 at our *** details were *** total number of rLN,the number of LNþ,and the LNR were calculated and measured against the *** receiver-operating characteristic(ROC)curve of patients with LNþwas ***:Of the 670 patients included in our study,337 were men(50.3%)and the mean age was 69.2 *** correlation with prognosis of the LNR is greater than that of the LNR adjusted to RL(LNR/RL),both in subjects with positive nodes(n=312)and in all cases(n=670).The LNR presents a higher prognostic value than LNR/RL and RL in patients with LNþexcept for metastatic recurrence,for which the predictive value appears slightly higher for LNR/*** statistical significance of the maximal divergence in Kaplan–Meier survival plots was demonstrated for the LNR(P=0.043),not for LNR/RL(P=0.373)and RL alone(P=0.314).Conclusion:An increase in RL causes an increase in the number of harvested lymph nodes without affecting the number of LNþ,thus representing a confounding factor that could alter the prognostic value of the *** larger-scale studies are needed to confirm these findings.

关键词： colorectal cancer lymph-node ratio resection length prognostic value

Synthesis and evaluation of C-glycosides as hydrotropes and solubilizing agents

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2010年第9期53卷 1957-1962页

作者： RANOUX Adeline LEMIEGRE loc BENVEGNU Thierry Ecole Nationale Supérieure de Chimie de Rennes CNRS UMR 6226Université Européenne de Bretagne

This work presents expeditious synthesis of C-glycoside amphiphiles in aqueous media from unprotected di-or mono-saccharides.A Horner-Wadsworth-Emmons/Michael addition/Barbier allylation sequence led to C-glycosides that exhibit hydrotropic *** hydrotropic and solubilizing properties of these homoallylic alcohols including a β-C-glycoside moiety as well as additional β-C-glycosidic ketones with a short(C7) alkyl chain are also described and compared with those of commercial O-glucoside references.

关键词： C-glycoside amphiphiles Horner-Wadsworth-Emmons reaction Barbier allylation green chemistry hydrotropes

Structure and reflective properties of Al-Cu-Fe quasicrystalline thin film prepared by laser induced arc method

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2004年第Z1期47卷 133-140页

作者： MOU Huiqing SHAO Tianmin se Dao State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China

Al-Cu-Fe thin films were prepared by laser induced arc (laser-arc) method from a single source-Al63Cu25Fe12 alloy, which was proved to consist of quasicrystalline phase together with approximant phase. The composition of the deposited films meets the requirement for formation of icosahedral symmetry phase. Quasicrystalline phase was obtained after annealing the amorphous as-deposit film samples. The optical properties of the samples were investigated. Thin film samples of Al, Cu and Fe deposited under the same condition were employed for comparison. The results showed specific reflective properties of Al-Cu-Fe quasicrystal thin film in some wavelength range. The optical conductivity of the films exhibited a negative peak, centered about 440 nm in range of 190to 800 nm. The Al-Cu-Fe quasicrystal thin films could absorb almost all the ray in the wavelength range from 420nm to 450 nm. The ratio of absorption was greater than 99%.

关键词： quasicrystal, thin film, reflection ratio, laser-arc.

What security Questions Do Developers Ask？ A Large-Scale Study of Stack Overflow Posts

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2016年第5期31卷 910-924页

作者： Xin-Li Yang David lo Xin Xia Zhi-Yuan Wan Jian-Ling Sun College of Computer Science and Technology Zhejiang University Hangzhou 310027 China School of Information Systems Singapore Management University Singapore Singapore

security has always been a popular and critical topic. With the rapid development of information technology, it is always attracting people＇s attention. However, since security has a long history, it covers a wide range of topics which change a lot, from classic cryptography to recently popular mobile security. There is a need to investigate security-related topics and trends, which can be a guide for security researchers, security educators and security practitioners. To address the above-mentioned need, in this paper, we conduct a large-scale study on security-related questions on Stack Overflow. Stack Overflow is a popular on-line question and answer site for software developers to communicate, collaborate, and share information with one another. There are many different topics among the numerous questions posted on Stack Overflow and security-related questions occupy a large proportion and have an important and significant position. We first use two heuristics to extract from the dataset the questions that are related to security based on the tags of the posts. And then we use an advanced topic model, Latent Diriehlet Allocation （LDA） tuned using Genetic Algorithm （GA）, to cluster different security-related questions based on their texts. After obtaining the different topics of security-related questions, we use their metadata to make various analyses. We summarize all the topics into five main categories, and investigate the popularity and difficulty of different topics as well. Based on the results of our study, we conclude several implications for researchers, educators and practitioners.

关键词： security Stack Overflow empirical study topic model

Cellular factors involved in the hepatitis C virus life cycle

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2021年第28期27卷 4555-4581页

作者： Hui-Chun Li Chee-Hing Yang Shih-Yen lo Department of Biochemistry Tzu Chi UniversityHualien 970Taiwan Department of Laboratory Medicine and Biotechnology Tzu Chi UniversityHualien 970Taiwan Department of Laboratory Medicine Buddhist Tzu Chi General HospitalHualien 970Taiwan

The hepatitis C virus(HCV),an obligatory intracellular pathogen,highly depends on its host cells to propagate *** HCV life cycle can be simply divided into several stages including viral entry,protein translation,RNA replication,viral assembly and *** of cellular factors involved in the HCV life cycle have been identified over more than thirty years of *** of these cellular factors has provided extensive insight into HCV replication *** of these cellular factors are targets for anti-HCV *** this review,we summarize the well-characterized and recently identified cellular factors functioning at each stage of the HCV life cycle.

关键词： Hepatitis C virus Cellular factor Viral entry Translation Replication Assembly Release

Simplifying living donor liver transplantation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2010年第1期9卷 9-14页

作者： see Ching Chan Chung Mau lo Sheung Tat Fan Department of Surgery The University of Hong KongQueen Mary Hospital

BACKGROUND: Living donor liver transplantation is a complex surgical operation. Treatment policies and operative techniques evolved in the last two decades. DATA SOURCES: Our center's experience in living donor liver transplantation was reviewed in conjunction with relevant publications in the literature. RESULTS: The surgical techniques and perioperative surgical therapeutics could be modified towards simplicity. Examples include regular inclusion of the middle hepatic vein without compromising the venous outflow of the donor's remnant left liver. This provides excellent venous outflow, which is crucial for a small-for-size graft. Immunosuppression and hepatitis B suppression are steroid free and hepatitis B immunoglobulin free respectively. CONCLUSION: The most practical way to achieve high graft and recipient survival rates with an acceptably low donor risk is through design of a protocol that simplifies the surgery and postoperative management.

关键词： simplifying right liver living donor liver transplantation

A comparative analysis of alternative approaches to fitting species-abundance models

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2012年第1期5卷 32-45页

作者： sean R.Connolly loïc M.Thibaut School of Marine and Tropical Biology and ARC Centre of Excellence for Coral Reef Studies James Cook UniversityTownsvilleQueensland 4811Australia

Aims Fits of species-abundance distributions to empirical data are increasingly used to evaluate models of diversity maintenance and community structure and to infer properties of communities,such as species *** distributions predicted by several models are the Poisson lognormal(PLN)and the negative binomial(NB)distribution;however,at least three different ways to parameterize the PLN have been proposed,which differ in whether unobserved species contribute to the likelihood and in whether the likelihood is conditional upon the total number of individuals in the *** of these has an analogue for the ***,we propose a new formulation of the PLN and NB that includes the number of unobserved species as one of the estimated *** investigate the performance of parameter estimates obtained from this reformulation,as well as the existing alternatives,for drawing inferences about the shape of species abundance distributions and estimation of species *** We simulate the random sampling of a fixed number of individuals from lognormal and gamma community relative abundance distributions,using a previously developed‘individual-based’bootstrap *** use a range of sample sizes,community species richness levels and shape parameters for the species abundance distributions that span much of the realistic range for empirical data,generating 1000 simulated data sets for each parameter *** then fit each of the alternative likelihoods to each of the simulated data sets,and we assess the bias,sampling variance and estimation error for each *** Findings Parameter estimates behave reasonably well for most parameter values,exhibiting modest levels of median ***,for the NB,median error becomes extremely large as the NB approaches either of two limiting *** both the NB and PLN,>90%of the variation in the error in model parameters across parameter sets is explained by three quantities that corresponded to t

关键词： Poisson lognormal negative binomial Poisson gamma species-abundance distributions species richness