检索结果-南通市图书馆

维普期刊数据库

Mapping frontier molecular orbitals using photocurrents

在线全文

学校读者我要写书评

暂无评论

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

作者： Ping Zhou j..0} Stoddart Hongliang Chen Stoddart Institute of Molecular Science Department of ChemistryZhejiang UniversityHangzhou 310027China Zj..Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311215China Department of Chemistry Northwestern University2145 Sheridan RoadEvanstonIllinois 60208USA School of Chemistry University of New South WalesSydneyNSW 2052Australia

In the regime of coherent transport, the conductance of a molecular j..ction is governed(Fig. 1a) by the probability of electron transmission between the metal electrodes, a physica property which is affected significantly by the hybridization of frontier molecular orbitals(FMOs) with the continuous band of energy levels on the electrodes.

关键词： frontier molecular orbitals

维普期刊数据库

Endoscopic ultrasound-guided elastography in the nodal staging of oesophageal cancer

在线全文

学校读者我要写书评

暂无评论

World j..rnal of Gastroenterology 2012年第9期18卷 889-895页

作者： Stuart Paterson fraser Duthie Adrian j..tanley Department of Gastroenterology Forth Valley Royal Hospital Department of Pathology Glasgow Royal Infirmary Department of Gastroenterology Glasgow Royal Infirmary

AIM： To assess quantitative endoscopic ultrasound （EUS）- guided elastography in the nodal staging of oesophago- gastric cancers.METHODS： This was a single tertiary centre study as- sessing 50 patients with established oesophago-gastric cancer undergoing EUS-guided fine needle aspiration biopsy （FNAB） of lymph nodes between j..y 2007 and j..y 2009. EUS-guided elastography of lymph nodes was performed before EUS-FNAB. Standard EUS charac- teristics were also described. Cytological determination of whether a lymph node was malignant or benign was used as the gold standard for this study. Comparisons of elastography and standard EUS characteristics were made between the cytologically benign and malignant nodes. The main outcome measure was the accuracy of elastography in differentiating between benign and malignant lymph nodes in oesophageal cancers.

关键词： Endoscopic ultrasound Oesophageal cancerLymph nodes Elastography Tumour staging

Subtypes of functional dyspepsia

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 j..rnal of Gastroenterology 2006年第17期12卷 2667-2671页

作者： Georgina Baker Robert j..0} Graeme Young Department of Gastroenterology Repatriation General 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 gastrointestinal symptoms and a normal endoscopy. To standardise research-based approaches, an initial categorisation of into sub groups was agreed to, based on clusters of symptoms. However the early expectation that these subgroups would be associated with distinct pathophysiologies amenable to specific therapy has not been realised. A classification based on the most troublesome symptom has been suggested but the utility of this is also unclear. More recent data suggest that some of the pathophysiologic dysfunctions may be associated with specific symptoms and so provide a better tool for grouping patients. But this approach remains incomplete as current insights into the pathogenesis 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 largely empiric.

关键词： Functional dyspepsia Classification Subtypes Symptoms Pathophysiology Management

Making chiral molecular knots and links stereospecifically

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2023年第3期10卷 58-59页

作者： Huang Wu Chun Tang Long Zhang j..0} Stoddart Department of Chemistry Northwestern University School of Chemistry University of New South Wales Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Zj..Hangzhou Global Scientific and Technological Innovation Center

Topological structures [1,2],i.e.,knots and links,grace the macroscopic world in the form of biomorphs and artificial tools,all the way down to the molecular scale,such as catenated DNA and *** inherently exists in structures in which mirror-image topologies cannot be superimposed upon themselves without disassembling the topological *** the chirality we are most familiar with is based on stereogenic centers,

关键词：

LOV to BLUF： Flavoprotein Contributions to the Optogenetic Toolkit

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2012年第3期5卷 533-544页

作者： j..n M. Christie j..de Gawthorne Gillian Young Niall j..fraser^c and Andrew j..Roe Institute of Molecular Cell and Systems Biology College of Medical Veterinary and Life Sciences University of Glasgow UK Institute of Infection immunity and Inflammation College of Medical Veterinary and Life Sciences University of Glasgow UK Institute of Cardiovascular and Medical Sciences College of Medical Veterinary and Life Sciences University of Glasgow UK

Optogenetics is an emerging field that combines optical and genetic approaches to non-invasively interfere with cellular events with exquisite spatiotemporal control. Although it arose originally from neuroscience, optogenetics is widely applicable to the study of many different biological systems and the range of applications arising from this tech- nology continues to increase. Moreover, the repertoire of light-sensitive proteins used for devising new optogenetic tools is rapidly expanding. Light, Oxygen, or Voltage sensing （LOV） and Blue-Light-Utilizing flavin adenine dinucleotide （FAD）（BLUF） domains represent new contributors to the optogenetic toolkit. These small （100-140-amino acids） flavoprotein modules are derived from plant and bacterial photoreceptors that respond to UV-A/blue light. In recent years, considerable progress has been made in uncovering the photoactivation mechanisms of both LOV and BLUF domains. This knowledge has been applied in the design of synthetic photoswitches and fluorescent reporters with applications in cell biology and biotechnology. In this review, we summarize the photochemical properties of LOV and BLUF photosensors and highlight some of the recent advances in how these flavoproteins are being employed to artificially regulate and image a variety of biological processes.

关键词： Blue-Light.Utilizing FAD chromophore flavin fluorescence light, oxygen or voltage optogenetics photo- receptor protein engineering

Proximal gastric motility in critically ill patients with type 2 diabetes mellitus

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 j..rnal of Gastroenterology 2007年第2期13卷 270-275页

作者： Nam Q Nguyen Robert j..0} Laura K Bryant Marianne Chapman Richard H Holloway Department of Gastroenterology Hepatology and General Medicine Royal Adelaide Hospital South Australia Investigation and Procedures Unit Repatriation General Hospital South Australia Anaesthesia and Intensive Care Royal Adelaide Hospital South Australia

AIM： To investigate the proximal gastric motor response to duodenal nutrients in critically ill patients with longstanding type 2 diabetes ***： Proximal gastric motility was assessed （using a barostat） in 10 critically ill patients with type 2 diabetes mellitus （59±3 years） during two 60-min duodenal infusions of Ensure （1 and 2 kcal/min）, in random order, separated by 2h fasting. Data were compared with 15 non-diabetic critically ill patients （48 ± 5 years） and 10 healthy volunteers （28 ±3 years）. RESULTS： Baseline proximal gastric volumes were similar between the three groups. In diabetic patients, proximal gastric relaxation during I kcal/min nutrient infusion was similar to non-diabetic patients and healthy controls. In contrast, relaxation during 2 kcal/ min infusion was initially reduced in diabetic patients （P 〈 0.05） but increased to a level similar to healthy humans, unlike non-diabetic patients where relaxation was impaired throughout the infusion. Duodenal nutrient stimulation reduced the fundic wave frequency in a dose-dependent fashion in both the critically ill diabetic patients and healthy subj..ts, but not in critically ill patients without diabetes. Fundic wave frequency in diabetic patients and healthy subj..ts was greater than in non-diabetic ***： In patients with diabetes mellitus, proximal gastric motility is less disturbed than nondiabetic patients during critical illness, suggesting that these patients may not be at greater risk of delayed gastric emptying.

关键词： Proximal gastric function Diabetes mellitus type 2 Critical illness Enteral nutrition

Mechanisms underlying feed intolerance in the critically ill: Implications for treatment

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 j..rnal of Gastroenterology 2007年第29期13卷 3909-3917页

作者： Adam Deane Marianne j..hapman Robert j..0} Laura K Bryant Carly Burgstad Nam Q Nguyen Intensive Care Unit Royal Adelaide Hospital Adelaide South Australia Discipline of Medicine University of Adelaide and Investigation and Procedures Unit Repatriation General Hospital Adelaide South Australia Investigation and Procedures Unit Repatriation General Hospital Adelaide South Australia Department of Gastroenterology and Hepatology Royal Adelaide Hospital Adelaide South Australia

Malnutrition is associated with poor outcomes in critically ill patients. Although nutritional support is yet to be proven to improve mortality in non-malnourished critically ill patients, early enteral feeding is considered best practice. However, enteral feeding is often limited by delayed gastric emptying. The best method to clinically identify delayed gastric emptying and feed intolerance is unclear. Gastric residual volume （GRV） measured at the bedside is widely used as a surrogate marker for gastric emptying, but the value of GRV measurement has recently been disputed. While the mechanisms underlying delayed gastric emptying require further investigation, recent research has given a better appreciation of the pathophysiology. A number of pharmacological strategies are available to improve the success of feeding. Recent data suggest a combination of intravenous metoclopramide and en/thromycin to be the most successful treatment, but novel drug therapies should be explored. Simpler methods to access the duodenum and more distal small bowel for feed delivery are also under investigation. This review summarises current understanding of the factors responsible for, and mechanisms underlying feed intolerance in critical illness, together with the evidence for current practices. Areas requiring further research are also highlighted.

关键词： Critical illness Enteral nutrition Gastric emptying Gastric motility Gastrointestinal hormones Metoclopramide Erythromycin Prokinetic therapy

A carbon- and oxygen-isotope record of recent environ- mental change from Qinghai Lake, NE Tibetan Plateau

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第14期48卷 1463-1468页

作者： A.C.G.henderson j...Holmes ZHANGj..wu M.j..eng L.R.Carvalho EnvironmentalChangeResearchCentre(ECRC) DepartmentofGeographyUniversityCollegeLondon26BedfordWayLondonWC1H0APUK CenterforAridEnvironmentandPaleoclimateResearch NationalLaboratoryofWesternChina'sEnvironmentalSystemsLanzhouUniversityLanzhou730000China NERCIsotopeGeosciencesLaboratory(NIGL) BritishGeologicalSurveyKeyworthNottingham.NG125GGUK Presentaddress:CentreforEcologyandHydrology(CEH) EdinburghBushEstatePenicuikMidlothianEH260OB.UK

A c. 300-year oxygen and carbon isotope record derived from fine-grained and ostracod carbonate from Qinghai Lake testifies to dramatic interannual tointerdecadal limnological change. Fine-grained carbonates, which are mainly authigenic, are likely to have formed in the epilimnion of the lake and their isotopic composition reflects the summer temperature and, more importantly, the isotopic composition of the near-surface waters, which is mainly a function of evaporative concentration. Ostracod shells are secreted in the benthos of the lake, and their isotopic composition reflects summer bottom-water conditions, together with fractionation effects, which may differ between species. Differences betweencontemporaneous values from authigenic carbonates and ostracod shells may provide an indication of stratification within the lake and variations in effective precipitation over the northeast part of the Tibetan Plateau over the past 300 years. A period of moderate evaporative concentration, from about 300 to 100 yr BP, was interrupted by a marked wet phase from ～100 to 40 yr BP, which was in turnfollowed by a return to drier conditions in the most recent part of the *** increase in ? 18O values in the latter part of the record accords well withinstrumental records of lake-level lowering and salinity increase since about 1955 AD.

关键词：中国西藏东北部环境变化碳同位素氧同位素季风古气候青海湖

维普期刊数据库

An algorithm for family screening for coeliac disease

在线全文

学校读者我要写书评

暂无评论

World j..rnal of Gastroenterology 2006年第48期12卷 7805-7809页

作者： j..elyn S fraser Alistair L King H j..ia Ellis Simon j..oodie Ingvar Bj..nason j..l Swift Paul j..iclitira Division of Nutritional Sciences King's College London United Kingdom Division of Nutritional Sciences King’s College London United Kingdom

AIM: To assess the level of undiagnosed coeliac disease (CD) in relatives of patients affected by the condition. METHODS: We collected blood from 914 relatives of probands. We screened these individuals by ELISA for IgA and IgG tTG antibodies, confirming any positive IgA tTG results with an IgA EMA and looked for evidence of IgA deficiency in those who were IgG tTG positive alone, and performed IgG1 EMA in these individuals. We undertook HLA typing where positive screening was found, and this confirmed a strong prevalence of HLA- DQ2 in the coeliac population. Follow-up small intestinal biopsy was undertaken in cases with positive serological screening, wherever possible. RESULTS:Use of this serological screening algorithm revealed a prevalence of undiagnosed CD in 5%-6% of first degree relatives of probands. CONCLUSION:Our data suggests that first degree relatives of individuals with CD should be screened for this condition.

关键词： Coeliac disease Screening Endomysialantibody Familial study IgA deficiency Prevalence Tissue transglutaminase