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981.
Viral nervous necrosis(VNN)has emerged to become a major problem in the culture of larval and juvenile marine fish worldwide.Bioactive phytochemicals isolated from commonly available medicinal plants are often screened for their efficacy in controlling fish viral diseases.Occurrence of newer viral strains and resistance to existing antiviral drugs are problems currently as-sociated with treatment of VNN,which necessitates looking for alternate sources for effective antiviral drugs.The aim of the present study was to screen antiviral potential of gymnemagenol(C30H50O4)previously extracted from leaves of Gymnema sylvestre.The fish nodavirus,grouper nervous necrosis virus(GNNV)in infected Sahul Indian Grouper Eye(SIGE)cell lines were used to study the antiviral activity of gymnemagenol under in vitro conditions.The susceptibility of the virus to gymnemagenol was confirmed by measuring the viral titre(TCID50 mL?1)in virus-infected SIGE cells every 24 h.Gymnemagenol at 20 μg mL?1 inhibited the prolifera-tion of GNNV to 53% at the end of the 6th d by inhibiting the proliferation of GNNV-infected SIGE cells.The viable SIGE cells were reduced to 47% as determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.The viral titre(TCID50 mL?1)was also reduced to log 2.8 at the end of the 7th d in gymnemagenol-treated SIGE cells after inoculated with GNNV when compared to untreated control SIGE cell viral titre(log 4.1).Based on our results it can be concluded that gymnemagenol could be used as an antiviral agent against GNNV infection. 相似文献
984.
985.
TENSORIAL RESOLUTION:A DIRECT TRILINEAR DECOMPOSITION 总被引:4,自引:0,他引:4
EUGENIO SANCHEZ~ BRUCE R.KOWALSKI Laboratory for Chemometrics Department of Chemistry BG-.University of Washington Seattle WA U.S.A. Mobil Research Development Corporation Paulsboro Research Laboratory Billinsport Ro Paulsboro NJ U.S.A. 《地理学报(英文版)》1990,(1)
Modern instrumentation in chemistry routinely generates two-dimensional(second-order)arrays of data.Considering that most analyses need to compare several samples,the analyst ends up with a three-dimensional(third-order)array which is difficult to visualize or interpret with the conventional statisticaltools.Some of these data arrays follow the so-called trilinear model,(?)These trilinear arrays of data are known to have unique factor analysis decompositions which correspondto the true physical factors that form the data,i.e.given the array (?),a unique solution can be found inmany cases for each order X,Y and Z.This is in contrast to the well-known second-order bilinear datafactor analysis,where the abstract solutions obtained are not unique and at best cannot be easilycompared with the underlying physical factors owing to a rotational ambiguity.Trilinear decompositions have had the disadvantage,however,that a non-linear optimization withmany parameters is necessary to reach a least-squares solution.This paper will introduce a method forreducing the problem to a rectangular generalized eigenvalue-eigenvector equation where the eigenbectorsare the contravariant form(pseudo-inverse)of the actual factors.It is shown that the method works wellwhen the factors are linearly independent in at least two orders(e.g.X_(jr),and Y_(jr) are full rank matrices).Finally,it is shown how trilinear decompositions relate to multicomponent calibration,curve resolutionand chemical analysis. 相似文献
986.
987.
988.
A solution of the nonlinear problem for determining the wind velocity in frictionless atmosphere (the gradient wind) under given geopotential (pressure) field is proposed. The approach is analytical and is based on quadratic polynomial approximation of the geopotential field and linear approximation of the wind velocity field with respect to x and y, the coefficients of the expansions being functions of the time t. The derived system of ordinary nonlinear differential equations is analyzed as a dynamical system. Exact analytical solutions are found for some particular cases. Some of their properties bear a resemblance to those or really existing atmospheric vortices (cyclones and anticyclones). 相似文献
989.
J.H.HAN A.J.I.WARD B.K.LAVINE Department of Chemistry Clarkson University Potsdum NY U.S.A. 《地理学报(英文版)》1990,(1)
Because many pattern recognition techniques are predicated on the assumption of mutivariate normaldata,Monte Carlo simulation studies were performed to determine the number of samples that arenecessary to describe a multivariate normal population adequately.From these studies we have learnedthat hundreds of sainples are required.These results suggest that parametric procedures should only beused to analyze very large data sets. 相似文献
990.
PAUL BENJAMIN CRILLY Department of Electrical Computer Engineering Knoxville TN - U.S.A. 《地理学报(英文版)》1990,(1)
In previous papers Jansson's method was found to be successful at deconvolving severely overlapped gaschromatographic peaks.In the most recent paper the method was evaluated with respect to quantitativeaceuracy,peak area and retention time repeatability.The problems associated with deconvolving noisydata and some alternatives which can improve the ability of Jansson's method to deconvolve noisy dataare discussed.These alternatives include presmoothing the data with a nine-point,third-order polynomialfilter and data reblurring.This paper will test these methods on peaks with various degrees of resolutionand signal-to-noise ratios. 相似文献