检索结果-南通市图书馆

Chain length-dependent cooperativity in fatty acid binding and oxidation by cytochrome P450_(BM3)(CYP102A1)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Protein & Cell 2011年第8期2卷 656-671页

作者： Benjamin Rowlatt jake A.Yorke Anthony j.Strong Christopher j.C.Whitehouse Stephen G.bell luet-lok Wong Department of Chemistry University of OxfordInorganic Chemistry LaboratorySouth Parks RoadOxford OX13QRUK

Fatty acid binding and oxidation kinetics for wild type P450_(BM3)(CYP102A1)from Bacillus megaterium have been found to display chain length-dependent homotropic *** and 13-methyl-myristate display Michaelis-Menten behavior while there are slight deviations with myristate at low ionic *** shows Michaelis-Menten kinetics and hyperbolic binding behavior in 100 mmol/l phosphate,pH 7.4,but sigmoidal kinetics(with an apparent intercept)in low ionic strength buffers and at physiological phosphate *** low ionic strength buffers both the heme domain and the full-length enzyme show complex palmitate binding behavior that indicates a minimum of four fatty acid binding sites,with high cooperativity for the binding of the fourth palmitate molecule,and the full-length enzyme showing tighter palmitate binding than the heme *** first flavin-to-heme electron transfer is faster for laurate,myristate and palmitate in 100 mmol/l phosphate than in 50mmol/l Tris(pH 7.4),yet each substrate induces similar high-spin heme *** palmitate in low phosphate buffer concentrations,the rate constant of the first electron transfer is much larger than *** results suggest that phosphate has a specific effect in promoting the first electron transfer step,and that P450_(BM3) could modulate Bacillus membrane morphology and fluidity via palmitate oxidation in response to the external phosphate concentration.

关键词： P450_(BM3) monooxygenase fatty acid cooperativity allosteric effect CYP102A1

Electrospinning as a route to advanced carbon fibre materials for selected low-temperature electrochemical devices:A review

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

journal of Energy Chemistry 2021年第8期30卷 492-529,I0011页

作者： Yue Wen Matt D.R.Kok jorge Pavel Victoria Tafoya Ana Bjorge Sobrido Ellsworth bell jeff T.Gostick Servann Herou Philipp Schlee Maria-Magdalena Titirici Dan j.l.Brett Paul R.Shearing Rhodri jervis The Electrochemical Innovation lab Dept.of Chemical EngineeringUniversity College LondonTorrington PlaceWC1E 7JE LondonUK Queen Mary University of london School of Engineering and Materials ScienceMile End RoadE14NS LondonUK Department of Chemical Engineering University of WaterlooWaterlooCanada Department of Chemical Engineering Imperial College LondonSouth Kensington CampusSW72AZ LondonUK

Electrospinning has been proven as a highly versatile fabrication method for producing nano-structured fibres with controllable morphology,of both the fibres themselves and the void structure of the ***,it is possible to use heteroatom doped polymers or to include catalytic precursors in the electrospinning solution to control the surface properties of the *** factors make it an ideal method for the production of electrodes and flow media for a variety of electrochemical devices,enabling reduction in mass transport and activation overpotentials and therefore increasing ***,the use of biomass as a polymer source has recently gained attention for the ability to embed sustainable principles in the materials of electrochemical devices,complementing their ability to allow an increase in the use of renewable electricity via their *** this review,the historical and recent developments of electrospun materials for application in redox flow batteries,fuel cells,metal air batteries and supercapacitors are thoroughly reviewed,including an overview of the electrospinning process and a guide to best ***,we provide an outlook for the emerging use of this process in the field of electrochemical energy devices with the hope that the combination of tailored microstructure,surface functionality and computer modelling will herald a new era of bespoke functional materials that can significantly improve the performance of the devices in which they are used.

关键词： Electrospinning Redox flow batteries Fuel cells Metal-air batteries Supercapacitors

Primary care providers should prescribe aspirin to prevent cardiovascular disease based on benefit−risk ratio,not age

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

Family Medicine and Community Health 2021年第4期9卷 1-4页

作者： Kyungmann Kim Charles H Hennekens lisa Martinez j Michael Gaziano Marc A Pfeffer Bianca Biglione Alexander Gitin jeanne bell McCabe Thomas D Cook David l DeMets Sarah K Wood Biostatistics and Medical Informatics University of Wisconsin-Madison School of Medicine and Public HealthMadisonWisconsinUSA Medicine and Population Health and Social Medicine Florida Atlantic UniversityCharles E Schmidt College of MedicineBoca RatonFloridaUSA Medicine Harvard Medical SchoolBostonMassachusettsUSA Medicine University of Florida College of MedicineGainesvilleFloridaUSA

Recent guidelines restricted aspirin(ASA)in primary prevention of cardiovascular disease(CVD)to patients10%,benefits of ASA will generally outweigh risks of significant *** should be considered only after implementati... 详细信息

Recent guidelines restricted aspirin(ASA)in primary prevention of cardiovascular disease(CVD)to patientsld and more recent guidance tolysis,the Antithrombotic Trialists Collaboration reported a significant 12%reduction in CVD with similar benefit−risk ratios at older *** Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines,four trials were added to an updated *** produced a statistically significant 13%reduction in CVD with 95%confidence limits(0.83 to 0.92)with similar benefits at older ages in each of the *** care providers should make individual decisions whether to prescribe ASA based on benefit−risk ratio,not simply *** the absolute risk of CVD is>10%,benefits of ASA will generally outweigh risks of significant *** should be considered only after implementation of therapeutic lifestyle changes and other drugs of proven benefit such as statins,which are,at the very least,additive to *** perspective is that individual clinical judgements by primary care providers about prescription of ASA in primary prevention of CVD should be based on our evidence-based solution of weighing all the absolute benefits and risks rather than *** strategy would do far more good for far more patients as well as far more good than harm in both developed and developing *** new and novel strategy for primary care providers to consider in prescribing ASA in primary prevention of CVD is the same as the general approach suggested by Professor Geoffrey Rose decades ago.

关键词： prevention aspirin absolute

Effect of oxygen and nitrogen functionalization on the physical and electronic structure of graphene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2015年第8期8卷 2620-2635页

作者： Alexander j. Marsden Peter Brommer james j. Mudd M. Adam Dyson Robert Cook Maria Asensio jose Avila Ana levy jeremy Sloan David Quigley Gavin R. bell Neil R. Wilson Department of Physics University of Warwick Coventry UK Centre for Scientific Computing University of Warwick Coventry UK Synchrotron SOlEIl L'Orme des Merisiers Saint Aubin-BP 48 91192 Gifsur Yvette Cedex France

Covalent functionalization of graphene offers opportunities for tailoring its properties and is an unavoidable consequence of some graphene synthesis techniques. However, the changes induced by the functionalization are not well understood. By using atomic sources to control the extent of the oxygen and nitrogen functionalization, we studied the evolution in the structure and properties at the atomic scale. Atomic oxygen reversibly introduces epoxide groups whilst, under similar conditions, atomic nitrogen irreversibly creates diverse functionalities including substitutional, pyridinic, and pyrrolic nitrogen. Atomic oxygen leaves the Fermi energy at the Dirac point （i.e., undoped）, whilst atomic nitrogen results in a net n-doping; however, the experimental results are consistent with the dominant electronic effect for both being a transition from delocalized to localized states, and hence the loss of the signature electronic structure of graphene.

关键词： graphene functionalization chemical vapor deposition density functional theory

Non-interferometric photoacoustic remote sensing microscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

light(Science & Applications) 2017年第1期6卷 753-760页

作者： Parsin Hajireza Wei Shi Kevan bell Robert j Paproski Roger j Zemp Department of Electrical and Computer Engineering University of AlbertaEdmontonAlbertaT6G 2V4 Canada IllumiSonics Inc.5205-38A Ave.N.W.EdmontonAlbertaT6L 2J4Canada

Elasto-optical refractive index modulation due to photoacoustic initial pressure transients produced significant reflection of a probe beam when the absorbing interface had an appreciable refractive index *** effect was harnessed in a new form of non-contact optical resolution photoacoustic microscopy called photoacoustic remote sensing microscopy.A noninterferometric system architecture with a low-coherence probe beam precludes detection of surface oscillations and other phase-modulation *** probe beam was confocal with a scanned excitation beam to ensure detection of initial pressure-induced intensity reflections at the subsurface origin where pressures are *** studies confirmed signal dependence on optical absorption,index contrast and excitation *** vivo imaging of superficial microvasculature and melanoma tumors was demonstrated with~2.7±0.5μm lateral resolution.

关键词： all optical medical imaging optical resolution photoacoustic remote sensing

Efficacy and safety of tenofovir in chronic hepatitis B: Australian real world experience

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 Hepatology 2017年第1期9卷 48-56页

作者： Grace C lovett Tin Nguyen David M Iser jacinta A Holmes Robert Chen Barbara Demediuk Gideon Shaw Sally j bell Paul V Desmond Alexander j Thompson Department of Gastroenterology St Vincent’s Hospital Melbourne Faculty of Medicine University of Melbourne

AIMTo evaluate the long-term treatment outcomes of tenofovir therapy in patients in a real world Australian tertiary care setting. METHODSWe performed a retrospective analysis of treatment outcomes among treatment-naïve and treatment-experienced patients receiving a minimum 3 mo tenofovir therapy through St Vincent’s Hospital Melbourne, Australia. We included patients receiving tenofovir [tenofovir disoproxil fumarate (TDF)] monotherapy, as well as patients treated with TDF in combination with a second antiviral agent. Patients were excluded if they demonstrated human immune-deficiency virus/hepatitis C virus/hepatitis delta virus coinfection or were less than 18 years of age. We considered virological and biochemical response, as well as safety outcomes. Virological response was determined by measurement of hepatitis B virus (HBV) DNA using sensitive assays; biochemical response was determined via serum liver function tests; histological response was determined from liver biopsy and fibroscan; safety analysis focused on glomerular renal function and bone mineral density. The primary efficacy endpoint was complete virological suppression over time, defined by HBV DNA RESUlTSNinety-two patients were identified who fulfilled the enrolment criteria. Median follow-up was 26 mo (range 3-114). Mean age was 46 (24-78) years, 64 (70%) were male and 77 (84%) were of Asian origin. 55 (60%) patients were treatment-naïve and 62 patients (67%) were HBeAg-negative. Complete virological suppression was achieved by 45/65 (71%) patients at 12 mo, 37/46 (80%) at 24 mo and 25/28 (89%) at 36 mo. Partial virological response (HBV DNA 20-2000 IU/ml) was achieved by 89/92 (96.7%) of patients. Multivariate analysis showed a significant relationship between virological suppression at end of follow-up and baseline HBV DNA level (OR = 0.897, 95%CI: 0.833-0.967, P = 0.0046) and HBeAg positive status (OR = 0.373, 95%CI: 0.183-0.762, P = 0.0069). There was no difference in respon

关键词： Tenofovir Hepatitis B virus Australia Real-life Virological suppression Chronic hepatitis B

The Effects of Exercise on Serum Chemistry, Non-Esterified Fatty Acid, Insulin and Glucagon Dynamics during a 400 Meter Sprint in Racing Greyhounds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open journal of Veterinary Medicine 2015年第6期5卷 142-151页

作者： Michael j. bell Emily M. Donaldson Sabine Mann Robert l. Gillette Corri B. levine joseph j. Wakshlag Craigieburn Animal Hospital 9 Craigieburn Rd. Craigieburn Australia Cornell University College of Veterinary Medicine Department of Clinical Sciences Ithaca NY USA Cornell University College of Veterinary Medicine Department of Population Medicine Ithaca NY USA Red Bank Referral Center Sports Medicine and Rehabilitation Service Red Bank NJ USA

The effects of Greyhound racing on plasma insulin, glucagon and non-esterified fatty acid have not been extensively studied. We sought to examine the effects of exercise in 19 greyhounds trialed over 400 meters on serum biochemistry, osmolality, nonessential fatty acids, and the major glucoregulatory hormones insulin and glucagon, before and after racing. Due to the non-traditional dietary patterns of many racing Greyhounds, the diet was analyzed for macro and micro-nutrient assessment to determine adequacy of the diet. Many significant biochemical changes were observed and agreed with previous studies, except for low resting glucose, low post-exercise globulin and phosphorus concentrations, and a high CK both before and after exercise. Insulin concentrations increased 10 minutes post-exercise which might be a result of the rise in serum glucose observed. Non-esterified fatty acids decreased 10 minutes post-exercise, as a likely result of the insulin facilitated cellular uptake of fatty acids early in recovery. Glucagon concentrations did not change after exercise despite the rise in insulin. The diet analysis found some mineral deficiencies in sodium, selenium, iodine and copper;and contained a far higher protein and fat content, being atypical of diets that have been shown to improve the performance in racing Greyhounds.

关键词： Greyhound Insulin Glucagon Non-Esterified Fatty Acid Glucose

long-term outcomes after fractional flow reserve-guided percutaneous coronary intervention in patients with severe coronary stenosis

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 Geriatric Cardiology 2019年第4期16卷 329-337页

作者： Ying-Hua ZHANG jing lI Andreas j. Flammer Yoshiki Matsuo Moo-Sik lee Ryan j. lennon Malcolm R. bell David R. Holmes john F. Bresnahan Charanjit S. Rihal lilach O. lerman Amir lerman Division of Cardiology Xuanwu Hospital Capital Medical UniversityBeijingChina Division of Cardiovascular Diseases Mayo ClinicRochesterUSA Cardiovascular Center CardiologyUniversity Hospital ZurichSwitzerland Department of Preventive Medicine College of Medicine Konyang UniversityDaejeonSouth Korea Biomedical Statistics Mayo ClinicRochesterUSA Division of Nephrology and Hypertension Mayo ClinicRochesterUSA

Objective To explore the safety and efficacy of FFR-guided percutaneous coronary intervention (PCI) in vessels with severe diameter stenosis. Methods & Results Of 1090 patients undergoing fractional flow reserve (FFR) assessment from 2002 to 2009,we identified 167 patients in whom FFR was measured in at least one 70%–89% stenotic lesion. These patients were subdivided into an FFR-defer group (n = 49) if PCI was deferred (FFR > 0.80),and an FFR-perform group (n = 118) if PCI was performed (FFR ≤ 0.80). Comparatively,an additional 1176 patients undergoing PCI in at least one lesion with 70%–89% stenosis but without measurement of FFR served as a control (angiography- guided) group. Clinical outcomes were compared during a median follow-up of 49.0 months. The 5-year Kaplan-Meier estimated revascularization rates were 16% in the FFR-defer group and 33% in the FFR-perform group (P = 0.046). The incidence of major adverse cardiac events were comparable in these two groups (HR = 0.82,95% CI: 0.37–1.82,P = 0.63). The number of stents placed was significantly lower in the FFR-guided group (0.9 ± 0.8 vs. 1.4 ± 0.8,P lusions Functional revascularization for lesions with visually severe stenosis is clinically safe and associated with fewer stents use. This study suggests that extending the use of FFR to more severe coronary lesions may be reasonable.

关键词： Fractional flow reserve Outcome Percutaneous coronary intervention Severe stenosis Stent

Planting Geometry Effects on the Growth and Yield of Dryland Cotton

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

Agricultural Sciences 2018年第1期9卷 99-116页

作者： R. l. Baumhardt R. C. Schwartz G. W. Marek j. M. bell Soil and Water Management Research Conservation and Production Research Laboratory USDA-ARS Bushland TX USA Agronomy Texas A & M AgriLife Research and Extension Amarillo TX USA

The declining Ogallala Aquifer beneath the Southern High Plains may necessitate dryland crop production and cotton (Gossypium hirsutum l.) is a well-adapted and potentially profitable alternative crop. The limited growing season duration of the Texas Panhandle and southwestern Kansas, however, imposes significant production risk due to incomplete boll maturation. Emphasizing earlier boll production that is usually confined to sites on lower fruiting branches may reduce risk, but offsetting high planting densities are needed to maintain desirable lint yield. Our objectives were to quantify planting: 1) row width and 2) in-row spacing effects on growth, yield, and fiber quality of dryland cotton. Field tests of row widths from 0.25 to 0.76 m and plant densities with in-row spacing ranging from 0.075 to 0.15 m were conducted from 1999 to 2005 on a nearly level Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) managed in a wheat (Triticum aestivum l.), cotton, fallow (W-Ctn-F) rotation. To expand the basis of comparison, cotton growth and yields were simulated using GOSSYM and long-term (1958-2000) weather records from Bushland, TX, as input for all combinations of 0.38 or 0.76 m row widths and plant spacing of 0.075, 0.10 and 0.15 m. Experimental and computer simulated plant height and harvested boll number increased significantly with increased row spacing and, occasionally, in-row plant spacing. Modeled lint yield for 0.38 m rows decreased by approximately 50% compared with the 582 kg·ha-1 yield for conventional row spacing, which was practically duplicated by field observations in 2001 and 2004. Measured fiber quality occasionally improved with conventional row spacing over ultra-narrow rows, but was unaffected by plant spacing. Because narrow rows and frequent plant spacing did not improve lint yield or fiber quality of dryland cotton, we do not recommend this strategy to overcome a thermally limited growing season.

关键词： Dryland Crop Production Thermally limited Growing Season Ultra-Narrow Row Spacing