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Díaz MP Rizo OD Díaz AL Aparicio EE Díaz RR 《Journal of Zhejiang University. Science. B》2006,7(12):947-956
A discriminant method for optimizing activity in nuclear medicine studies is validated by comparison with ROC （received operating characteristic）-curves. The method is tested in 21 single photon emission computerized tomography （SPECT）, performed with a cardiac phantom. Three different lesions （Lb L2 and L3） were placed in the myocardium-wall by pairs fbr each SPECT. Three activities （84, 37 or 18.5 MBq） of 99mTc were used as background. Linear discriminant analysis was used to select the parameters that characterize image quality among the measured variables in the images [（Background-to-Lesion （B/Li） and Signal-to-Noise （S/N） ratios）]. Two clusters with different image quality （P=0.021 ） were obtained. The ratios B/Lj, B/L2 and B/L3 are the parameters used to construct the function with 100% of cases correctly classified into the clusters. The value of 37 MBq was the lowest tested activity for which good results for the B/Li ratios were obtained. The result coincides with the applied ROC-analysis （r=0.89）. 相似文献
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Academic deans annually negotiate for a fair share of university resources. Without quantitative accreditation standards to serve as minimum guidelines, the competition is more difficult. Peer institution comparison, derived from the analysis of quantitative data on resource and productivity variables, assists by providing less biased justification for budget requests. In this study, data from a national study of doctoral-granting teacher education programs was used for a factor analysis of key resource and productivity variables. Seven alternative cluster analysis methods were used and compared. Three follow-up procedures (analysis of variance, discriminant analysis, and classification analysis) tested the cluster analysis results to verify the differences between clusters and their internal homogeneity on three different cluster solutions. The classification analysis showed that 88.2% of the 76 programs were correctly classified on the five-cluster solution produced using Ward's minimum variance method. The practical use of such data suggests that Cattell's pattern of profile similarly is a useful beginning to compare programs on factor scores; following that, raw data on each key variable might be used to prepare individual program profiles for more specific comparison. 相似文献
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Mark S. Freeman B. Grant Hayes Tyson H. Kuch Gordon Taub 《Counselor Education & Supervision》2007,46(4):254-265
Selecting a single psychotherapeutic orientation can be a challenge for counselor education students. The authors examined the relationship between counseling theory selection and personality variables of students enrolled in a counseling theories course. A discriminant function analysis was used to identify the personality traits that would determine theoretical orientation choice. No statistically significant results were found. Results indicated that students showed no personality‐based preference of theory. Additionally, no significant differences were found on selected subscales of the Myers—Briggs Type Indicator (I. B. Myers, M. H. McCaulley, N. L. Quenk, & A. L. Hammer, 1998) and the Self‐Directed Search (J. L. Holland, B. A. Fritzsche, & A. B. Powell, 1996; J. L. Holland, A. B. Powell, & B. A. Fritzsche, 1994). 相似文献
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6种常用抗菌中药对3株常见病原性细菌的抑菌作用检测 总被引：2，自引：0，他引：2
目的:建立抗菌中药对临床常见病原性细菌抑菌作用的检测方法。方法:选择6种常用抗菌中药(黄连、苦参、连翘、大黄、生地、知母),分别采用水提法制备至质量浓度1mg/L。应用液体稀释法测定上述中药对金黄色葡萄球菌、大肠埃希菌和铜绿假单胞菌的最低抑菌浓度(MIC)。结果:建立了中药抑菌作用的检测方法。黄连、大黄与连翘抑制细菌的作用较强,MIC值均≤0.05mg/L,其中黄连对金黄色葡萄球菌的抑菌作用最强(MIC值为0.00625mg/L)。结论:应用本方法可以进行中药抑菌作用的检测。抗菌中药对所试验菌种表现不同的抑菌作用。 相似文献
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Liu Zhijing Xu Cong Tian Ran Wang Wan Ma Jiage Gu Liya Liu Fei Jiang Zhanmei Hou Juncai 《Journal of Zhejiang University. Science. B》2021,22(7):533-547
Lactic acid bacteria(LAB) are a representative probiotic. As the dominant flora in the human intestinal tract, LAB can regulate the balance of human intestinal flora and improve host health. The purpose of this study was to isolate and screen LAB that are well suited to the intestinal characteristics of the Chinese population, with excellent probiotics and high antibacterial activity. After 16 S ribosomal RNA(rRNA) homology and phylogenetic tree analysis, potential probiotics were tested for their antibacterial activity, resistance to artificial gastrointestinal fluid and drugs, surface hydrophobicity, and safety.Three strains of LAB with acid resistance, bile salt resistance, epithelial cell adhesion, and no multidrug resistance were selected: Lactobacillus salivarius, Leuconostoc lactis, and Lactobacillus paracasei. Analysis of the antibacterial active substances in the three strains and their fermentation broths revealed that the main antibacterial substances of L. lactis were organic acids, whereas those of L. salivarius and L. paracasei were organic acids and bacteriocins with broad-spectrum antibacterial activity. These three strains of probiotic LAB with high antibacterial activity were identified as bacterial resources that could potentially be used to develop probiotic preparations for the prevention and treatment of intestinal diseases caused by intestinal pathogens. 相似文献
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The geometric shapes of specimens are important in impact tensile tests because geometric shapes determine the stress states of the specimens, and precise geometric shapes can obtain proper material properties without non-material factors. The aim of this study was to investigate the 1D form of the stress by changing the length-to-diameter （L/D） ratios of specimens. The experiments were carried out on a split Hopkinson tensile bar （SHTB）-rotating disk indirect bar-bar tensile impact apparatus. The L/D ratios of the LY12CZ specimens used in the test ranged from 1 to 5. Results show that the specimens can be used to obtain exact parameters of materials under the proposed conditions when the L/D ratio is greater than 2. This is because the longer length will reduce or eliminate the effects of the interfaces. 相似文献
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Aerobically activated sludge processing was carried out to treat terylene artificial silk printing and dyeing wastewater (TPD wastewater) in a lab-scale experiment, focusing on the kinetics of the COD removal. The kinetics parameters determined from experiment were applied to evaluate the biological treatability of wastewater. Experiments showed that COD removal could be divided into two stages, in which the ratio BOD/COD (B/C) was the key factor for stage division. At the rapid-removal stage with B/C>0.1, COD removal could be described by a zero order reaction. At the moderate-removal stage with B/C<0.1, COD removal could be described by a first order reaction. Then Monod equation was introduced to indicate COD removal. The reaction rate constant (K) and half saturation constant (KS) were 0.0208-0.0642 L/(gMLSS)·h and 0.44-0.59 (gCOD)/L respectively at 20 ℃-35 ℃. Activation energy (Ea) was 6.05×104 J/mol. By comparison of kinetic parameters, the biological treatability of TPD wastewater was superior to that of traditional textile wastewater. But COD removal from TPD-wastewater was much more difficult than that from domestic and industrial wastewater, such as papermaking, beer, phenol wastewater, etc. The expected effluent quality strongly related to un-biodegradable COD and kinetics rather than total COD. The results provide useful basis for further scaling up and efficient operation of TPD wastewater treatment. 相似文献
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用Tris-HCl缓冲液抽提、硫酸铵分级沉淀从黄粉虫体内获得N-乙酰氨基葡萄糖苷酶(NAGase,EC3.2.1.52)研究VC、VB1、VB2、VB5、VB6、VB12等对黄粉虫NAGase活力的影响。结果表明:VC、VB1、VB6对NAGase起抑制作用;而VB5、VB2、VB12对NAGase的作用不明显。进一步研究VC和VB6的抑制作用动力学,结果表明:VC和VB6对酶的抑制作用可逆,VC为混合型抑制,VB6为非竞争型抑制。测得VC对酶的抑制常数KI与KIS分别为37.63mmol/L、95.64mmol/L;VB6对酶的抑制常数KI与KIS均为13.75mmol/L。 相似文献
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Kaylee Litson Christian Geiser G. Leonard Burns Mateu Servera 《Structural equation modeling》2017,24(1):31-51
Multitrait-multimethod (MTMM) analyses are used in psychology to assess convergent and discriminant validity and to study method effects. Most current MTMM approaches assume that measures have equal convergent and discriminant validity across the entire range of trait values and thus do not account for potential trait × method interactions. A novel approach is presented that allows analyzing trait × method interactions using factor mixture modeling. The new MTMM mixture model allows identifying latent classes of individuals who differ with respect to convergent and discriminant validity. The new approach was applied to mother’s and father’s ratings of children’s attention deficit hyperactivity disorder (ADHD) symptoms (N = 618). Results revealed four latent classes: one with no symptom levels, two with low symptom levels, and one with moderate symptom levels. Three classes showed evidence for convergent and discriminant validity, whereas a low symptom class lacked convergent validity for ratings of inattention.
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Identification of rice seed varieties using neural network 总被引：1，自引：0，他引：1
A digital image analysis algorithm based color and morphological features was developed to identify the six varieties (ey7954, syz3, xs1 1, xy5968, xy9308, z903) rice seeds which are widely planted in Zhejiang Province. Seven color and fourteen morphological features were used for discriminant analysis. Two hundred and forty kernels used as the training data set and sixty kernels as the test data set in the neural network used to identify rice seed varieties. When the model was tested on the test data set,the identification accuracies were 90.00％, 88.00％, 95.00％, 82.00％, 74.00％, 80.00％ for ey7954, syz3, xsl 1, xy5968, xy9308,z903 respectively. 相似文献
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Habib M Hussain I Fang WH Rajput ZI Yang ZZ Irshad H 《Journal of Zhejiang University. Science. B》2006,7(4):320-323
In this experiment conducted to study the inactivation dynamics of infectious bursal disease virus （IBDV） by binary ethylenimine （BEI） in comparison with formalin, IBDV was isolated from the bursa of infected chickens and its confirmation was done by agar gel precipitation test. Viral suspensions were subjected to inactivation with BEI and formalin for pre-set time in- tervals. BEI was employed at concentrations of 0.001 and 0.002 mol/L while formalin was used at 0.1% and 0.2%. Sampling was done at 6, 12, 24, 36 and 48 h of incubation and samples were tested for their inactivation status in 9-day-old embryonated eggs and 3-week-old broiler chickens. IBDV was completely inactivated by 0.001 and 0.002 mol/L BEI after 36 h of incubation at 37℃, whereas formalin at 0. 1% and 0.2% concentrations inactivated IBDV in 24 h. 相似文献
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Timothy M. Flynn 《Journal of Experimental Education》2013,81(2):46-51
A multiple-choice behavioral observation scale designed to be used by preschool teachers (N = 424) was factor analyzed to obtain factor coefficients. The four factors obtained were cognitive skills, self-control, relationship with achievement model, and dependency. The factor coefficients were then applied to the ratings of 153 preschool disadvantaged children by 33 teachers and 64 teacher aides. Three multi-trait, multi-rater matrices were analyzed using Campbell and Fiske’s convergent discriminant validation procedures. The analyses supported convergent and discriminant validity of three of the four traits. 相似文献
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Antibacterial and antifungal activities of different parts of Tribulus terrestris L. growing in Iraq
Antimicrobial activity of organic and aqueous extracts from fruits, leaves and roots of Tribulus terrestris L., an Iraqi medicinal plant used as urinary anti-infective in folk medicine, was examined against 11 species of pathogenic and non-pathogenic microorganisms: Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Corynebacterium diphtheriae, Escherichia coli,Proteus vulgaris, Serratia marcescens, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans using microdilution method in 96 multiwell microtiter plates. All the extracts from the different parts of the plant showed antimicrobial activity against most tested microorganisms. The most active extract against both Gram-negative and Gram-positive bacteria was ethanol extract from the fruits with a minimal inhibitory concentration (MIC) value of 0.15 mg/ml against B. subtilis,B. cereus, P. vulgaris and C. diphtheriae. In addition, the same extract from the same plant part demonstrated the strongest antifungal activity against C. albicans with an MIC value of 0.15 mg/ml. 相似文献
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INTRODUCTIONInordertogetpliableandelegantterylenefabricjustlikesilk,terylenegreigeclothisalwayspretreatedwithalkali-decompositionprocesswh-ereinterylenegreigeclothishydrolyzedtosomeextentinNaOHsolutionatcertaintemperature(T)andpressure.Duringthisprocess,thesuperficialterylenefibreispeeledofffromtheclothanddis-solvedintosolution,inwhichteryleneacid(TA)andethyleneglycolaredischargedaspollutantsinwastewater.Theobtainedterylenefabricwithsi-lkenwrinkleandsoftfeelingiscalledartificialsilkfabr… 相似文献
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Xue-ying QIN Jing-lun WANG Dao-ping TANG Yong-jin MAI Ling-zhi ZHANG 《浙江大学学报(A卷英文版)》2013,14(7):514-519
{3-[2-(2-methoxyethoxy) ethoxy]-propyl} triethoxysilane (TESM2) was synthesized and used as an electrolyte additive to improve the performances of lithium-ion batteries (LIBs). The electrochemical properties of the electrolyte (1 mol/L lithium hexafluorophosphate (LiPF6)/ethylene carbonate (EC):diethylene carbonate (DEC):dimethyl carbonate (DMC), 1:1:1) with different contents of TESM2 were characterized by ionic conductivity measurement, galvanostatic charge/discharge test of graphite/Li half cells, and electrochemical impedance spectroscopy. Both the cycling performances and C-rate capabilities of graphite/Li half cells were significantly improved with an optimized content of 15% TESM2 in the electrolyte. The graphite/Li half cell delivered a very high specific capacity of 370 mAh/g at 0.2C rate without any capacity loss for 60 cycles, and retained a capacity of 292 mAh/g at 2C rate. The solid electrolyte interphase (SEI) film on the surface of the graphite anode was investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), indicating that TESM2 was effectively involved in the formation of SEI film on the surface of graphite. 相似文献
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Construction and characterization of a cDNA library from human liver tissue with chronic hepatitis B 总被引：3，自引：0，他引：3
Chen XH Chen Z Yao HP Chen F Zhu HH Zhou HJ 《Journal of Zhejiang University. Science. B》2005,6(4):288-294
INTRODUCTION Chronic hepatitis B virus (HBV) infection is aserious clinical problem because of its wide distribu-tion and possible adverse consequences, such as he-patic decompensation, cirrhosis and/or primary livercancer (PLC). The natural course of chronic HBVinfection is characterized by a series of hepatitic flaresor exacerbations and remissions (Ganem and Prince,2004). The severity, extent, duration and frequency ofhepatic histopathological changes in hepatitic flaresare d… 相似文献
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Yue-fei Wang Jie Wang Jing Wu Ping Xu Yi-qi Wang Jun-jie Gao Danielle Hochstetter 《Journal of Zhejiang University. Science. B》2014,15(2):173-180
The conditions for extracting polysaccharides from tea (Camellia sinensis L.) fruit peel (TFPPs) were studied. Three parameters (temperature, time, and liquid/solid ratio) affecting the extraction of TFPP were optimized using response surface methodology (RSM). Under the optimized conditions, the yield of TFPP was predicted to be 4.98%. The physicochemical properties, in vitro antioxidant activities, and inhibitory effects on α-glucosidase of fractionated TFPPs (TFPP-0, TFPP-20, TFPP-40, and TFPP-60) were investigated. We found that the TFPPs were all acid protein-bound heteropolysaccharides, although with different chemical compositions. They had not only remarkable scavenging activity on 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and reducing activity, but also excellent inhibitory potential against α-glucosidase in vitro. Our results suggest that tea fruit peel could be treated as a potential bioresource for the development of polysaccharide antioxidants. 相似文献