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41.
通过对服装在线社群特征的分析,引入社群认同为中介变量,构建服装在线社群特征、社群认同和品牌忠诚度之间的影响模型并提出假设.通过问卷调研,采用因子分析和回归分析探索服装在线社群特征、社群认同和品牌忠诚度之间的关系.研究结果显示,信息分享、感知价值、功能收益、共同意识都会通过社群认同正向影响品牌忠诚度,其影响重要程度为社群认同>感知价值>功能收益>信息分享>共同意识.研究结果为企业运营服装在线社群提供参考.  相似文献   
42.
Mobile ad-hoc networks (MANET) operate like self organizing entity. The mobile nodes are operate in a host as well as in a router and dynamic topology. In MANET every network node operates autonomously. It has limited resources like power, bandwidth and storage capacity. Selection of a propagation model plays the vital role of application possibilities in MANET. In this paper, calculations have been performed for three propagation models: Two-ray ground, COST 231 and Okumura–Hata model. The paper shows the impact of these propagation models based on Ad-hoc on-demand distance vector (AODV) protocol at 1.5 GHz frequency, varying transmitted power and number of nodes. This paper also studies effects of the propagation models with the conclusion of choosing the most accurate propagation model. Okumura–Hata propagation model shows better results at 1.5 GHz frequency as compared to COST 231 and Two-ray ground model in open space using Network Simulator (NS 2.35). Two-ray ground propagation model shows better results with varying transmitted power and number of nodes as compared to COST 231 and Okumura–Hata model.  相似文献   
43.
It is estimated that more than one-third of the world population is infected with Mycobacterium tuberculosis. Pyrazinamide (PZA) plays a unique role in shortening therapy because it kills a population of semilatent tubercle bacilli residing in an acidic environment. Niosomes are vesicles made up of non-ionic surfactant and exhibit behavior similar to liposomes in vivo. Preparation of PZA niosomes took place using different molar ratios of Span 60 and Span 85, with cholesterol (CH) i.e. Span: CH (1:1) and (4:2). Dicetyl phosphate and stearyl amine were used in preparation of negative and positively charged niosomes, respectively. Free PZA was separated by cooling centrifugation and estimated spectrophotometrically at 268.4 nm. Niosomes were characterized by electron microscopy and differential scanning calorimetry. The highest percentage PZA entrapped was obtained using Span 60 and the molar ratio (4:2:1) negatively charged niosomes. This was followed by the neutral PZA neutral (4:2) Span 60 niosomes. Biological evaluation of selected PZA niosomal formulations took place on guinea pigs infected with M. tuberculosis. The present work is an attempt to target maximum concentration of PZA to the affected site (lungs) and to exclude undesirable side effects and decrease toxicity. Macrophage targeting and overcoming drug resistance is our final goal.  相似文献   
44.
Evidence for adverse effects of screen media exposure has led to recommendations to limit children's screen time. This paper describes a randomized controlled trial of SMART (Student Media Awareness to Reduce Television), an 18-lesson, theory-based classroom curriculum to reduce screen time among third and fourth grade children in two matched public elementary schools ( n = 181). Intervention school children significantly reduced their weekday television viewing and weekday and Saturday video game playing compared to controls. Greater effects were found among boys and more adult-supervised children. Mothers, fathers, and siblings and other children in intervention school households also reduced their television viewing. The findings demonstrate the efficacy of a classroom intervention to reduce screen time among elementary school children and their family/household members.  相似文献   
45.
Family studies have shown that in some populations up to 75% of the variation of body mass index can be explained by genetic factors. However, in humans, no major obesity gene has been identified to date. In contrast, there are a number of genetically well defined animal models for obesity. In two of those models (ob/ob and db/db), defects in the same pathway are responsible for obesity. Recently, some evidence has been found for the OB gene also being involved in human obesity. In this study we investigated the potential role of the OB receptor (OBR) in the etiology of massive obesity in humans using familial linkage analyses and case-control association studies. The typing of two microsatellite markers (D1S198 and D1S209), flanking the OBR gene, in 256 sib pairs showed no evidence for linkage with obesity. In order to be able to detect small gene effects, association studies with a 3'-UTR insertion/deletion polymorphism were carried out. The results of these analyses remained non-significant (chi 2 = 3.442, P = 0.18). However, subjects heterozygous for the insertion/deletion polymorphism showed a slight trend towards lower insulin values 30 min after an oral glucose load compared to homozygous individuals (P = 0.02). In summary, our results do not support a major role of the human OBR gene in the development of morbid obesity in our population.  相似文献   
46.
A significant source of confusion in the marital observation area is the proliferation of systems for collapsing microbehavioral codes into categories. This study used an archival data set of 995 couples' videotaped conflict negotiations coded with the Marital Interaction Coding System-IV (MICS). A factor analysis was conducted to provide some empirically based guidance for the formation of coding categories. Four factors emerged for both men and women: Hostility, Constructive Problem Discussion, Humor, and Responsibility Discussion. Suggestions are made for category formation with MICS codes and for the development of a new coding system based on these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
47.
Arsenic is an element that is ubiquitous in the environment and is known to form compounds with toxic, even carcinogenic properties. Arsenic toxicity is a function of its chemical form (species). Identification of arsenic species is necessary to accurately determine the transformation and fate of arsenicals as well as the actual risk posed by arsenic contamination. We report X-ray absorption near-edge structure (XANES) measurements of 16 biologically important arsenic compounds. Solid and aqueous standards were studied for differences in XANES spectral features, white line positions, stability during exposure to the beam, and stability between two beam exposures separated by 48 h. Samples containing As(III) (11870.0-11871.7+/-0.5 eV) and As(V) (11872.6-11875.3+/-0.5 eV) were easily distinguished by white line energies and could be further subdivided into a total of seven groups. Valuable examples include As(III)-sulfur compounds (11870.0+/-0.5 eV), arsenobetaine and arsenocholine (11872.6+/-0.5 eV), and a dimethyl arsinyl riboside (11873.3+/-0.5 eV). A growing number of environmental and biological studies use X-ray absorption spectroscopy (XAS) results to complement their more traditional analyses. Results provided here are intended to help make XAS more accessible to new users interested in the study of arsenic in the environment.  相似文献   
48.
Friction is one of the most important parameters in sheet metal forming. Friction conditions are influenced by the texture of the sheet surface, by the surface or coating of the tools and by the lubrication. The aluminium alloy AA 5182 with EDT surface has been studied and tested at various angles between rolling and sliding direction. The friction behaviour observed in experiments at different normal pressures based on Coulomb’s friction law are shown and discussed in this article. Moreover, local surface topography and lubricant distribution in the contact area are described.  相似文献   
49.
The electrorheological (ER) behavior of modified montmorillonite (MMT) suspensions in polydimethylsiloxane is studied. As established by rotational viscometry, the samples with a dispersed phase concentration from 1 to 8 wt % reveal viscous Newtonian behavior and dramatically change their properties to elastic when electric field is applied. The rheological characteristics of the suspensions over 0–7 kV mm−1 range of electric field strengths are also studied. Novel X-ray diffraction method is developed to evaluate the suspension of the filler in a siloxane medium and to calculate the degree of its exfoliation. The dependence of exfoliation degree, dielectric, and ER characteristics on the type of modifier in the MMT structure is considered. Based on the obtained data, a new model of system behavior with the various types of fillers is proposed and the prospects of utilizing MMT as a filler for ER fluids are demonstrated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47678.  相似文献   
50.
The Sacramento-San Joaquin Delta is the major drinking water source for 23 million California residents. Consequently, many studies have examined disinfection byproduct (DBP) formation in relation to Delta dissolved organic carbon (DOC) concentration. However, DOC characteristics within the Delta are not the same as those entering downstream water treatment facilities. As water is transferred to Southern California through the California Aqueduct, a 714.5 km-open channel, it is exposed to sunlight, potentially altering DBP precursors. We collected water from three sites within the Delta and one nearthe California Aqueduct, representing different DOC sources, and irradiated them in a solar simulator at a dose equivalent to that received during four days conveyance in the aqueduct. Photolytic changes in DOC were assessed by measuring CO2 and organic acid production, fluorescence, and ultraviolet absorbance over time. Trihalomethane (THM) and haloacetic acid (HAA) formation potentials, as well as the distribution of hydrophobic, transphilic, and hydrophilic acid fractions were determined at exposures equivalent to one and four days. Solar irradiation significantly decreased ultraviolet absorbance and fluorescence intensity, produced organic acids, and increased the hydrophilic fraction of waters. These changes in DOC caused a shift in bromine incorporation among the THM and HAA species. Our results are the first to demonstrate the importance of sunlight in altering DOC with respect to DBP formation.  相似文献   
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