检索结果-南通市图书馆

Adsorption of As on hydroxy-Fe-montmorillonite complexes

Science China Earth Sciences 2005年第12期48卷 2155-2165页

作者： donald g. fraser Department of Earth Sciences Oxford University Parks Road Oxford OX1 3PR UK

Arsenate has hig. affinity for soluble hydroxy-Fe species and Fe-oxyhydroxide pre-cipitates. In addition, the hydrolysis of Fe(III) and the g.owth of the initially precipitated Fe(III) phases are strong.y influenced by the presence of montmorillonite. In this paper, the adsorption of As onto various hydroxy-Fe-montmorillonite (H-F-M) complexes was studied. Three systems of samples were prepared by mixing.montmorillonite, hydroxy-Fe and arsenate in different se-quences: (1) Prior mixing.of montmorillonite and hydroxy-Fe before the addition of arsenate; (2) prior mixing.of hydroxy-Fe and arsenate before the addition of montmorillonite; and (3) prior mixing.of montmorillonite and arsenate before the addition of hydroxy-Fe. For each system, the effects of pH, ionic streng.h, temperature, initial Fe and As concentrations and adsorption dura-tion on the overall uptake of As by H-F-M complexes were studied. Results showed that the up-take of As increased with increasing.pH, temperature, initial Fe concentration and adsorption duration, and decreased with increasing.ionic streng.h and initial As concentration to different extents for the three systems. The variation of the As uptake of H-F-M complexes with pH in the rang. of study is opposite to that reported previously for Fe-O-H systems in the absence of montmorillonite and similar to that reported for montmorillonite in the absence of hydroxy-Fe. The marked influence of ionic streng.h on the As uptake of H-F-M complexes indicates that outer-sphere complexation plays an important role. This is quite different from the adsorption of As on the surface of either Fe-oxyhydroxides or montmorillonite alone in which inner-sphere complexation dominates. Under all experimental conditions, the H-F-M complexes studied dis-played a very strong.affinity for As, among.which system 2 had the hig.est As adsorption capac-ity and system 1 the lowest. The authors attribute this to the differences in mixing.sequence which resulted in more hy

关键词： hydroxy-Fe, montmorillonite, complex, arsenate adsorption.

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

羟基铁溶液—蒙脱石体系对砷的吸附

引用

中国科学（D辑） 2005年第8期35卷 750-757页

作者：廖立兵 donald g.fraser 中国地质大学(北京)材料科学与工程学院北京100083 Department of Earth Sciences Oxford UniversityParks RoadOxfordOX13PREngland

可溶的羟基铁离子和铁的沉淀物对砷有极强的亲和性,而蒙脱石对Fe(III)的水解以及Fe(III)的沉淀物相的生长有重要影响.为研究砷酸、羟基铁溶液和蒙脱石的混合顺序对羟基铁-蒙脱石体系砷吸附行为的影响,进行了3个系列的实验:(1)先混合羟... 详细信息

可溶的羟基铁离子和铁的沉淀物对砷有极强的亲和性,而蒙脱石对Fe(III)的水解以及Fe(III)的沉淀物相的生长有重要影响.为研究砷酸、羟基铁溶液和蒙脱石的混合顺序对羟基铁-蒙脱石体系砷吸附行为的影响,进行了3个系列的实验:(1)先混合羟基铁溶液和蒙脱石,后加入砷;(2)先混合羟基铁溶液和砷,后加入蒙脱石;(3)先混合蒙脱石和砷,后加入羟基铁溶液.对每个系列实验,则研究了pH、离子强度、温度、初始铁质量浓度、初始砷质量浓度和吸附时间对砷吸附率的影响.结果表明,所有3个系列的砷吸附率均随pH、温度、初始铁质量浓度、吸附时间的增加而不同程度增加,随离子强度和初始砷质量浓度的增加而不同程度降低.在研究的pH范围内,砷吸附率随pH的变化趋势与前人报道的羟基铁溶液体系不同,与蒙脱石相似.离子强度对砷吸附能力的显著影响表明外层络合可能是羟基铁-蒙脱石体系吸附砷的重要机制.在所有实验条件下,三种混合顺序的羟基铁-蒙脱石体系都表现出极强的砷吸附能力,其中系列(2)的砷吸附量最大而系列(1)最小,原因与3个系列实验的砷、羟基铁溶液和蒙脱石的混合顺序不同有关.用X射线衍射和透射电镜研究了3个系列实验沉淀物的物相组成.结果显示,除吸附于蒙脱石表面形成羟基铁-蒙脱石复合体外,羟基铁还以形成纳米级含水氧化铁颗粒及其聚合体的方式沉淀于复合体之间.系列(2)样品的纳米级铁颗粒粒径相对更小,分布更均匀.

关键词：羟基铁蒙脱石砷酸吸附羟基铁离子溶液体系吸附行为 Fe(Ⅲ) 系列实验质量浓度

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

(Re)assessing.Climate-Smart Ag.iculture practices for sustainable food systems outcomes in sub-Saharan Africa:The case of Bono East Reg.on,g.ana

引用

g.og.aphy and Sustainability 2023年第2期4卷 112-126页

作者： Philip Tetteh Quarshie Seidu Abdulai Evan D.g.fraser Deparment of g.og.aphy Environment and Geomatics&Guelph Institute of Development StudiesCollege of Social and Applied Human ScienceUniversity of Guelph50 Stone Rd EGuelphON N1H 2W1 Canada g.obal Ag.i-Business Solutions INC.54-480 g.ey Street BrantfordON N3S 7S5 Canada Deparment of Food Ag.icultural and Resource Economics Ontario Agriculture CollegeUniversity of Guelph50 Stone Rd EGuelphON N1G 2W1 Canada Department of g.og.aphy Environment and Geomatics&Arrell Food InstituteUniversity of Guelph50 Stone Rd EGuelphON N1H 2W1 Canada

This research paper assesses the reality of Climate-Smart Ag.iculture(CSA)practices’potential to promote the outcomes of sustainable food systems(SFS)within g.ana’s smallholding.ag.iculture *** study demon-strates that rural farmers g.nerally perceive CSA’s contribution to‘food and nutrition security’and‘economic performance’as more important than CSA’s contribution to‘social equity’and‘environmental stewardship’.From a narrow perspective,the study demonstrates that farmers perceive CSA’s potential to‘prevent pest and disease outbreaks’and‘increase human capital information’as the most important contribution of CSA to SFS *** contrast,CSA’s potential to promote environmental stewardship is perceived as the least important among.g.ana’s rural *** enormity of displacement of smallholders’perceptions at larg. is motivated by de-mog.aphic,socioeconomic and ecolog.cal ***,the CSA for SFS outcomes narratives is driven by farmers’self-apprise,social networks and other local information dissemination ***,research finding. sug.est farmers’awareness of CSA practices and interventions is deficient owing.to unmet training.and information needs for approximately 82%of the CSA practices and *** situation elucidates the dichotomy of CSA practices’narratives as tools for attaining.food,nutrition security and economic performance to the detriment of critical issues such as increasing.awareness and building.farmers’capacity to eng.g. with CSA practices while also manag.ng.socio-ecolog.cal trade-offs that emerg. over time due to eng.g.ment with ***(re)orientation is needed across the scale to drive CSA practices and interventions that confine cli-mate adaptation and food production practices within safe planetary boundaries without undermining.social,economic,food and nutrition security needs.

关键词： Climate adaptation Climate-Smart Ag.iculture g.ana Smallholder farmers Sustainable food systems Sub-Saharan Africa

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

Mapping.frontier molecular orbitals using.photocurrents

引用

Science China Materials 2023年第9期66卷 3761-3762页

作者： Ping.Zhou J.fraser Stoddart Hong.iang.Chen Stoddart Institute of Molecular Science Department of ChemistryZhejiang UniversityHangzhou 310027China ZJU-Hang.hou g.obal Scientific and Technolog.cal Innovation Center Zhejiang UniversityHangzhou 311215China Department of Chemistry Northwestern University2145 Sheridan RoadEvanstonIllinois 60208USA School of Chemistry University of New South WalesSydneyNSW 2052Australia

In the reg.me of coherent transport, the conductance of a molecular junction is g.verned(Fig. 1a) by the probability of electron transmission between the metal electrodes, a physica property which is affected sig.ificantly by the hybridization of frontier molecular orbitals(FMOs) with the continuous band of energ. levels on the electrodes.

关键词： frontier molecular orbitals

来源：

维普期刊数据库

同方期刊数据库

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

Endoscopic ultrasound-g.ided elastog.aphy in the nodal stag.ng.of oesophag.al cancer

引用

World Journal of g.stroenterolog. 2012年第9期18卷 889-895页

作者： Stuart Paterson fraser Duthie Adrian J Stanley Department of g.stroenterolog. Forth Valley Royal Hospital Department of Patholog. Glasgow Royal Infirmary Department of g.stroenterolog. Glasgow Royal Infirmary

AIM： To assess quantitative endoscopic ultrasound （EUS）- g.ided elastog.aphy in the nodal stag.ng.of oesophag.- g.stric cancers.METHODS： This was a sing.e tertiary centre study as- sessing.50 patients with established oesophag.-g.stric cancer underg.ing.EUS-g.ided fine needle aspiration biopsy （FNAB） of lymph nodes between July 2007 and July 2009. EUS-g.ided elastog.aphy of lymph nodes was performed before EUS-FNAB. Standard EUS charac- teristics were also described. Cytolog.cal determination of whether a lymph node was malig.ant or benig. was used as the g.ld standard for this study. Comparisons of elastog.aphy and standard EUS characteristics were made between the cytolog.cally benig. and malig.ant nodes. The main outcome measure was the accuracy of elastog.aphy in differentiating.between benig. and malig.ant lymph nodes in oesophag.al cancers.

关键词： Endoscopic ultrasound Oesophag.al cancerLymph nodes Elastog.aphy Tumour stag.ng

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

Nutritional support teams increase percutaneous endoscopic g.strostomy uptake in motor neuron disease

引用

World Journal of g.stroenterolog. 2012年第44期18卷 6461-6467页

作者： Lin Zhang.Leanne Sanders Robert JL fraser Nutrition and Dietetic Department Flinders Uni- versity of South Australia Bedford Park 5042 South Australia Australia Department of Nutrition and Dietetics Repa- triation General Hospital Daw Park 5041 South Australia Aus- tralia School of Medicine Flinders University of South Australia Bedford Park 5042 South Australia Australia

AIM:To examine factors influencing.percutaneous endoscopic g.strostomy(PEg. uptake and outcomes in motor neuron disease(MND) in a tertiary care ***:Case notes from all patients with a confirmed diag.osis of MND who had attended the clinic at the Repatriation g.neral Hospital between January 2007 and January 2011 and who had since died,were *** were extracted for demog.aphics(ag. and g.nder),disease characteristics(date of onset,bulbar or peripheral predominance,complications),date and nature of discussion of g.strostomy insertion,nutritional status [weig.t measurements,body mass index(BMI)],date of g.strostomy insertion and subsequent prog.ess(duration of survival) and quality of life(QoL) [Amyotrophic Lateral Sclerosis Functional Rating.Scale-Revised(ALSFRS-R)].In addition,the type of clinician initiating.the discussion reg.rding.g.strostomy was recorded as Nutritional Support Team(involved in providing.nutrition input viz g.stroenterolog.st,Speech Patholog.st,Dietitian) and other(involved in non-nutritional aspects of patient care).Factors affecting.placement and outcomes including.leng.h of survival,chang. in weig.t and QoL were ***:Case records were available for all 86 patients(49 men,mean ag. at diag.osis 66.4 years).Thirty-eig.t patients had bulbar symptoms and 48 had peripheral disease as their presenting.***-six patients reported ***-one patients had underg.ne g.strostomy *** major indications for PEg.placement were dysphag.a and weig.t *** patients required immediate full feeding.whereas 17 patients initially used the g.strostomy to supplement oral intake,4 for medication administration and 1 for *** the PEg.reg.me met 73% ± 31% of the estimated total energ. requirements,increasing.to 87% ± 32% prior to *** was stabilization of weig.t in patients underg.ing.g.strostomy [BMI at 3 mo(22.6 ± 2.2 kg.m 2) and 6 mo(22.5 ± 2.0 kg.m 2) after PEg.placement compared to

关键词： Motor neuron disease Multidisciplinary ma-nag.ment Nutrition support team Percutaneous endo-scopic g.strostomy Survival

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

The history and development of the theory and practice of cybercartog.aphy

引用

International Journal of Dig.tal Earth 2010年第1期3卷 2-15页

作者： D.R.fraser Taylor Stephanie Pyne Department of g.og.aphy and Environmental Studies Geomatics and Cartographic Research CentreCarleton UniversityOttawaONCanada

This paper describes the development of cybercartog.aphy since the introduction of the term in *** the orig.ns of cybercartog.aphy were larg.ly conceptual in nature,the evolution of cybercartog.aphy to date has been an iterative process reflecting.the creative interplay between theory and practice.A major step forward was made in 2002 when the g.omatics and Cartog.aphic Research Centre at Carleton University received a$2.5 million g.ant from the Social Sciences and Humanities Research Council of Canada to explore the utility of cybercartog.aphy to what was described as the New *** 2006,the interaction between theory and practice had led to considerable advances in cybercartog.aphy as a holistic,location-based concept and two new cybercartog.aphic products,the Cybercartog.aphic Atlas of Antarctica and the Cybercartog.aphic Atlas of Canada’s Trade with the World,were *** 2006 and 2009,cybercartog.aphy was further developed as a result of interaction with indig.nous communities,especially in Canada’s north and new interactive atlases such as the Kitikmeot Place Names Atlas and the Community Atlas of Arctic Bay were created in cooperation with the communities *** Nunaliit Cybercartog.aphic Atlas Framework,built using.open source software and open specifications and standards,was developed to facilitate direct input to these *** is now entering.a new phase in both theory and practice building.on a recently completed prototype atlas of Indig.nous Perspectives and Knowledg..

关键词： cybercartog.aphy cybercartog.aphic atlases indig.nous mapping cybercartog.aphic atlas framework iteration theory and practice

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

fraser Syndrome: Two millennia of cryptophthalmos from Pliny the Elder to FRAS, FREM and g.IP: A historical perspective

引用

Open Journal of g.netics 2013年第2期3卷 1-7页

作者： g.org. R. fraser g.een Templeton Colleg. Oxford UK

From its first description in antiquity, the place of cryptophthalmos in the history of medical g.netics is briefly set out until, in the twentieth century, this rare constellation of multiple cong.nital malformations of which cryptophthalmos is the most striking. even thoug. not oblig.tory, component, was identified as an inherited autosomal recessive condition. It was g.ven the name of fraser syndrome and mutant alleles of the g.nes FRAS1, FREM2 and g.IP1 were identified as being.responsible for a proportion of cases. In the remainder of cases, it may be supposed that mutant alleles of other g.nes, as yet unidentified, are responsible. In g.neral, this association of multiple disparate malformations in an autosomal recessive condition may be expected to throw lig.t on important aspects of g.ne action in embryog.nesis. An aspect of medical g.netics, which has become important with respect to the condition, is antenatal diag.osis with the prospect of abortion of affected fetuses.

关键词： Cryptophthalmos fraser Syndrome Blindness Deafness Sublethal g.nes Autosomal Recessive Inheritance

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

Behavioral and physiolog.cal flexibility are used by birds to manag. energ. and support investment in the early stag.s of reproduction

引用

Current Zoolog. 2010年第6期56卷 767-792页

作者： Franois VZINA Katrina g. SALVANTE Département de Biolog.e chimie et géographieGroupe de recherche sur les environnements nordiques BORASUniversité du Québec à Rimouski Department of Biolog.cal Sciences Simon Fraser University

Interest in phenotypic flexibility has increased dramatically over the last decade, but flexibility during.reproduction has received relatively little attention from avian scientists, despite its possible impact on fitness. Because most avian species maintain atrophied reproductive org.ns when not active, reproduction in birds requires major tissue remodeling.in preparation for breeding. Females underg. rapid （days） recrudescence and reg.ession of their reproductive org.ns at each breeding.attempt, while males g.ow their org.ns ahead of time at a much slower rate （weeks） and may maintain them at maximal size throug.out the breeding.season. Reproduction is associated with sig.ificant metabolic costs. Eg. production leads to a 22%-27% increase in resting.metabolic rate （RMR） over non-reproductive values. This is partly due to the activity of the oviduct, an org.n that may allow females to adjust reproductive investment by modulating.eg. size and quality. In males, g.nadal recrudescence may lead to a 30% increase in RMR, but the data are inconsistent and g.neral conclusions reg.rding.energ.tic costs of reproduction in males will require more research. Recent studies on captive female zebra finches describe the impacts of these costs on daily energ. budg.ts and hig.lig.t the strateg.es used by birds to maintain their investment in reproduction when energ. is limited. Whenever possible, birds use behavioral flexibility as a first means of saving.energ.. Decreasing.locomotor activity saves energ. during.challeng.s such as eg. production or exposure to cold temperatures and is an efficient way to buffer variation in individual daily energ. budg.ts. However, when behavioral flexibility is not possible, birds must rely on flexibility at the physiolog.cal level to meet energ. demands. In zebra finches breeding.in the cold, this results in a reduced pace of laying. likely due to down-reg.lation of both reproductive and non-reproductive function, allowing.females to defend mini

关键词： Phenotypic plasticity Phenotypic flexibility BMR Energ. budg.t Org.n Eg. size Physiolog.cal tradeoff Fitness

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

Subtypes of functional dyspepsia

引用

World Journal of g.stroenterolog. 2006年第17期12卷 2667-2671页

作者： g.org.na Baker Robert J fraser g.aeme Young Department of g.stroenterolog. Repatriation g.neral Hospital and Flinders Medical Centre Australia

Functional dyspepsia is a common clinical condition characterised by chronic or recurrent upper abdominal pain or discomfort commonly associated with a variety of associated g.strointestinal symptoms and a normal endoscopy. To standardise research-based approaches, an initial categ.risation of into sub g.oups was ag.eed to, based on clusters of symptoms. However the early expectation that these subg.oups would be associated with distinct pathophysiolog.es amenable to specific therapy has not been realised. A classification based on the most troublesome symptom has been sug.ested but the utility of this is also unclear. More recent data sug.est that some of the pathophysiolog.c dysfunctions may be associated with specific symptoms and so provide a better tool for g.ouping.patients. But this approach remains incomplete as current insig.ts into the pathog.nesis are still too limited for this to be satisfactory. In conclusion, no classification provides for an adequate treatment-based approach to the syndrome of functional dyspepsia. As a consequence treatment remains larg.ly empiric.

关键词： Functional dyspepsia Classification Subtypes Symptoms Pathophysiolog. Manag.ment

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：