检索结果-南通市图书馆

Response surface methodology-based optimization of ultrasound-assisted extraction of β-sitosterol and lupeol from Astragalus atropilosus(roots) and validation by HPTLC method

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

Asian Pacific Journal of Tropical Biomedicine 2020年第6期10卷 281-292页

作者： Perwez Alam Nasir A.siddiqui Ali s.Alqahtani Anzarul Haque Omer A.Basudan saleh I.Alqasoumi m.U.Khan Department of Pharmacognosy College of PharmacyKing Saud UniversityP.O.Box-2457Riyadh-11451Saudi Arabia Department of Pharmacognosy College of PharmacyPrince Sattam bin Abdulaziz UniversityAl-KharjKSA Department of Pharmaceutical Chem.s.ry&Pharmacognosy Unaizah College of PharmacyQassim UniversityAl QassimSaudi Arabia

Objective:To optimize the ultrasonication method for efficient extraction ofβ-sitosterol and lupeol from the roots of Astragalus atropilosus using Box-Behnken design of response surface methodology(Rsm),and its validation by high performance thin layer chromatography(HPTLC)***:Ultrasonication method was used to extractβ-sitosterol and lupeol from Astragalus atropilosus(roots).Rsm was used to optimize the different extraction parameters *** to solid ratio(10–14 m L/g),temperature(60-80℃)and time(40–60 min)to maximize the yield ofβ-sitosterol and *** quantitative estimation ofβ-sitosterol and lupeol was done in chloroform extract of Astragalus atropilosus by validated HPTLC method on 10 cm×20 cm glass-backed silica gel 60 F254 plate using hexane and ethyl acetate(8:2,v/v)as mobile ***:A quadratic polynomial model was found to be m.s. appropriate with regard to R1(yield of total extraction;R2/%CV=0.9948/0.28),R2(β-sitosterol yield;R2/%CV=0.9923/0.39)and R3(lupeol yield;R2/%CV=0.9942/0.97).The values of adjusted R2/predicted R2/signal to noise ratio for R1,R2,and R3 were 0.9782/0.9551/48.77,0.9904/0.9110/31.33,and 0.9927/0.9401/36.08,respectively,indicating a high degree of correlation and adequate *** linear correlation plot between the predicted and experimental values for R1,R2,and R3 showed high values of R2 ranging from 0.9905-0.9973.β-sitosterol and lupeol in chloroform extract of Astragalus atropilosus were detected at Rf values of 0.22 and 0.34,respectively,atλmax=518 *** optimized ultrasonic extraction produced 8.462%w/w of R1,0.451%w/w of R2 and 0.172%w/w of R3 at 13.5 m L/g liquid to solid ratio,78℃of temperature and 60 min of ***:The experimental findings of Rsm optimized extraction and HPTLC analysis can be further applied for the efficient extraction ofβ-sitosterol and lupeol in other species of Astragalus.

关键词： β-sitosterol Lupeol Box-Behnken design Astragalus High performance thin layer chromatography

Electronic structure Reconstruction across the Antiferromagnetic Transition in TaFe1.23Te3 spin Ladder

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 Physics Letters 2015年第2期32卷 127-130页

作者：徐敏王莉敏彭瑞葛青亲陈飞叶子荣张焱陈苏迪夏淼刘荣华 Arita m. shimada K. Namatame H. Taniguchi m. matsunami m. Kimura s. 史明陈仙辉尹卫国顾威谢斌平封东来 state Key Laboratory of surface Physics Department of Physicsand Advanced Materials LaboratoryFudan University Condensed matter Physics and materials science Department Brookhaven National Laboratory Collaborative Innovation Center of Advanced microstructures Hefei National Laboratory for Physical sciences at microscale and Department of Physics University of Science and Technology of China Hiroshima synchrotron Radiation Center Hiroshima University UVsOR Facility Institute for Molecular Science swiss Light source Paul-Scherrer Institute

Employing the angle-resolved photoem.s.ion spectroscopy, we study the electronic structure of TaFe1.23Te3, a two-leg spin ladder compound with a novel antiferromagnetic ground state. Quasi-two-dimensional （2D） Fermi surface is observed, with sizable inter-ladder hopping. moreover, instead of observing an energy gap at the Fermi surface in the antiferromagnetic state, we observe the shifts of various bands. Combining these observations with density-functional-theory calculations, we propose that the large scale reconstruction of the electronic structure, caused by the interactions between the coexisting itinerant electrons and local moments, is m.s. likely the driving force of the magnetic transition. Thus TaFe1.23Te3 serves as a simpler platform that contains similar ingredients to the parent compounds of iron-based superconductors.

关键词： Ta der Electronic structure Reconstruction across the Antiferromagnetic Transition in TaFe AFm

Hydrological modeling in a semi-Arid Catchment Using sWAT model

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 Environmental science and Engineering 2011年第12期5卷 1695-1701页

作者： m. m.s.ahi s. Benabdallah m.R. Boussema Laboratory of Remote sensing and Information system for spatial Reference National School of Engineers Tunis 1002 Tunisia Center of Water Technologies .National Institute for Scientific and Technology Research Soliman 8020 Tunisia

In the field of the water resources, hydrologic models have been used to assess water quality performance of complex watersheds and river basins. Hydrologic models can provide essential information for making decisions on sustainable management system of water resources within watersheds. The main objective of this study was to validate the performance of the soil and Water Assessment Tool （sWAT） and the feasibility of using this model as a simulator of runoff at a catchment scale in semi-arid area in Northwestern Tunisia. Calibration and validation of the model output were performed by comparing predicted runoff with corresponding measurements from the sarrath outlet for the periods 1990-1995 for calibration and 2000-2005 for validation. The time series for the years 1996-1999 showed discrepancies between the measured rainfall and the observed runoff indicating errors due to either the observations or to a dysfunction in the equipments. sensitivity analysis shows that sensitive parameters for the simulation of discharge include curve number, soil evaporation compensation factor, depth of water in shallow aquifer and slope of subbasin. statistical comparisons between monthly simulated results and observed data for the calibration period gave a reasonable agreement with a coefficient of determination （R2） greater than 0.75 and Nash-sutcliffe Coefficient （NsE） equal to 0.72. These values were respectively 0.70 and 0.64 for validation period. Overall, the sWAT model has the capability to predict runoff within a complex semi-arid catchment.

关键词： semi-arid catchment sWAT model runoff.

Phytoextraction of Nickel and Chrome in Paddy soil Amended With municipal solid Waste and sewage sludge

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 Environmental science and Engineering 2011年第5期5卷 660-666页

作者： s.m. mousavi m.A. Bahmanyar H.A. Pirdashti soil science Department College of Crop Science Sari Agricultural Sciences and Natural Resources University Iran

A field study was conducted in the paddy soil amended with municipal solid waste （msW） and sewage sludge （ss） to find out total, DTPA extractable nickel （Ni） and chrome （Cr） in soil and their uptake by rice plant as split-plot arrangement based on randomized complete block design with three replications. The results indicated that the m.s. available Ni （2.10 ppm） measured under 3 years application of 40 ***~ msW＋I/2 chemical fertilizer （CF）. Also, with 3 application of 40 ton-ha＂l msW concluded the highest available Cr. The m.s. accumulation of Ni in root （14.51 ppm） and grain （8.89 ppm） happened under 3 years application of 40 ***-1 ss and 20 ton ha-1 msW＋I/2 CF, respectively. With application of 40 ***-1 ss and 40 ton ss＋1/2 CF, respectively happened the maximum Cr uptake by root and grain （12.43 and 3.65 ppm, respectively）.

关键词： municipal solid waste sewage sludge nickel chrome rice soil.

Petrographic characteristics coals, mahanadi Gondwana and paleomires of mand-Raigarh Basin, Chhattisgarh, India

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal science & Technology 2016年第2期3卷 165-183页

作者： A. s. Naik m. P. singh N. Volkmann P. K. singh D. mohantya D. Kumar Banaras Hindu University Varanasi India T U Bergakademie Freiberg Germany CsIR-Central Institute of mining and Fuel ResearchDhanbad India

mand-Raigarh coalfield is one of the largest coalfields in the mahanadi basin. The Geological survey of India carried out initial study primarily on exploration. However, detailed petrographic and geochemical characters of the coals have not been done so far. This investigation is an attempt for petrographic and geochemical appraisal of the coals. moreover, effort is also made for possible interpretation on development of coal facies. The results drawn from 30 composite coal samples suggest coals are rich in vitrinite, with collotelinite as the dominant maceral while liptinite macerals register low concentration. Dominant mineral assemblages found were clay minerals, pyrite was recorded as disseminated, framboidal and euhedral forms, carbonates recorded were mainly siderites. The vitrinite reflectance random （VRo） mean values range from 0.44 % to 0.56 %, and the rank of coal is suggested as high volatile ＇B＇ to ＇A＇ sub- bituminous in rank. The rock-eval pyrolysis reveal TOC content varying from 37 % to 68.83 %, while low hydrocarbon generating potential is evident from low $2 and Tmax values. The Hydrogen Index （HI） versus Oxygen Index （OI） plot reveal that the samples belong to Kerogen type--II-III with input dominantly from terrestrial source, some samples also fall in Kerogen type--II domain indicating lacustrine input. Vitrinite reflectance result indicate that the samples are immature and approaching oil window, which is in agreement with data of the Rock-Eval parameters. The gelification index （GI） and tissue preservation index （TPI） indicate that the coal developed in a telematic set up with high tree density. The ground water index （GWI） and vegetation index （VI） demonstrate that the peat developed as an ombrogenous bog.

关键词： mand-Raigarh coalfield Organic petrology Geochem.s.ry source rock

Cross inhibition improves activity selection when switching incurs time costs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2015年第2期61卷 242-250页

作者： Jam.s.A. R. mARsHALL Angelique FAVR EAU-PEIGN Lutz FROmHAGE John m. mCNAmARA Liarme F. s. mEAH Alasdair I. HOUsTON Department of Computer science and University of sheffield Sheffield S 1 4DP UK INRA UMR791 Modelisation Systemique Appliquee aux Ruminants F-75005 Paris France Department of Biological and Environmental science P.O. Box 35 FI-40014 University of Jyvaskyla Finland school of mathematics University of Bristol University Walk Bristol BS8 1TW UK school of Biological sciences University of Bristol Bristol Life Sciences Building 24 Tyndall Avenue Bristol BS8 1TQ UK AgroParisTech UMR Modelisation Systemique Appliquee anx Ruminants F-75005 Paris France

We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and exa- mine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has pre- viously been included in models of decision making, the question of what benefit it may provide to an animal＇s activity selection behaviour has not previously been studied. In neuroscience and in collective behaviour cross-inhibition, and other equivalent means of coupling evidence-accumulating pathways, have been shown to approximate statistically-optimal decision-making and to adaptively break deadlock, thereby improving decision performance. switching between activities is an ongoing decision process yet here we also find that cross-inhibition robustly improves its efficiency, by reducing the frequency of costly switches between behaviours .

关键词： Crossinhibition Geometric framework Foraging Activity selection Neuroscience Behaviour

Bryozoan Nodules as a Frame-Builder of Bryozoanmicroreef, middle miocene sediments, Egypt

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 Earth science 2015年第2期26卷 251-258页

作者： Abdelbaset s.El-sorogy Geology and Geophysics Department College of Science King Saud University Geology Department Faculty of Science Zagazig University

Bryozoan nodules, coralline algae, scleractinian corals and oysters form an important organic buildup, 1.2-4.5 m thick in the Langhian-serravaliann sediments of Egypt. Based on type, shape and size of the substrate, bryozoan nodules take tree-like and globular morphologies. Tree-like speci- mens reach 10 cm in maximum height and 3 cm in diameter, while Globular ones attain 9 cm in maxi- mum diameter. m.s. tree-like nodules are perforated with wide or narrow pores, few are non-perforated. Globulars and few tree-like forms are with mamelon-like structures. Perforations on the outer surfaces may indicate a symbiotic relationship between bryozoans and a live plant substrate. Nod- ules from Homiera and Gharra areas of the Cairo-suez District with wider perforations may indicate growth in slightly lighter or turbid areas of the continental shelf than those of North Western Desert of narrower perforations. Non-perforated nodules may assume an incrustation on ephemeral substrate .

关键词： miocene bryozoa frame builder microreef paleoecology Egypt.

P53 rs1042522 and CD95 rs1800682 genetic variations in HCV-4a response to antiviral therapy

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

Genes & Diseases 2015年第2期2卷 197-210页

作者： Ahmed A.Abd-Rabou Emad F.Eskander mervat s.mohamed shaymaa m.m.Yahya Ashraf El sherbini Olfat G.shaker Hormones Department Medical Research DivisionNational Research CentreCairo 12622Egypt Chem.s.ry Department Biochemistry SpecialtyFaculty of ScienceCairo UniversityEgypt Internal medicine Department Medical Research DivisionNational Research CentreCairoEgypt medical Biochem.s.ry and molecular Biology Department Faculty of MedicineCairo UniversityEgypt

Current estimates indicate that the hepatitis C(HCV)is the leading cause of mortality around the world,with infection rates steadily increasing in *** dual therapy for this silent epidemic with pegylated-interferon-a2b/ribavirin has markedly improved the success rates in genotype-4 *** was reported that apoptosis plays a vital mechanistic role in limiting viral replication.P53,a key regulator of apoptosis,induces CD95 gene expression and subsequently initiates apoptotic cascade to be *** current study examined the impact of P53 rs1042522 and CD95 rs1800682 polymorphisms on the treatment *** groups of 240 volunteers were enrolled in this study;86 in sustained virological responders group,74 in non-responders group,and 80 in control *** patients had HCV genotype-4a and were interferon treatment naı¨*** of HCV-RNA by qRT-PCR and histological scores were performed for all *** addition,genotyping of HCV-RNA,P53 rs1042522 Arg/Pro and CD95 rs1800682 A/G polymorphisms were investigated in all *** was resulted that P53 Pro/Pro homozygous genotype has high significant increase,while CD95 A/A homozygous genotype has high significant decrease when comparing non-responders with ***,it was concluded that Pro variant of P53 rs1042522 may be used as a genetic predictor for non-responsiveness,while A/A variant of CD95 rs1800682 may be used as a sensitive biomarker for responsiveness to antiviral therapy of HCV genotype-4a *** addition,low prolactin,high total testosterone,and high GH levels may provide prom.s.ng biomarkers for early prediction of the response when associated with these genetic polymorphisms.

关键词： CD95 rs1800682 HCV gentotype-4a P53 rs1042522 Response sNPs

Extracting a Heterogeneous social Network of AcademicResearchers on the Web Based on Information Retrieved from multiple sources

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Operations Research 2011年第2期1卷 33-38页

作者： Rasim m. Alguliev Ramiz m Aliguliyev Fadai s Ganjaliyev Institute of Information Technology Azerbaijan National Academy of Sciences Baku Azerbaijan

The majority of academic researchers present the results of their scientific activity on the Web. This trace can be used to derive useful information of their past, present activity and forecast the future intentions. Hence, social network of academic researchers can be of important value for scientific community. This information can be retrieved from various data source currently available on the Web. From each of them a separate net-work can be built. In this paper we present a method which can be used to combine multiple single-relational networks into a single network which will combine all relations, hence it will be multi-relational.

关键词： multi-Relational Networks Academic Researchers’ Network Data source Criteria