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41.
Adopting diffusion theory and the concept of social value orientation, the effects of personality traits on knowledge sharing in a virtual open content community are investigated. In addition to the main effects of personality, it was hypothesized that intrinsic motivations would moderate the effects on knowledge sharing. A sample of N = 256 active users of Wikipedia provided measures of personality, motivation, and knowledge sharing. Latent regression analyses support the notion that authorship of Wikipedia is associated with higher levels of trendsetting and a prosocial value orientation. Moreover, moderation analyses demonstrate that the effect of the latter is moderated by individual differences in motivations to write. Differences with regard to opinion leadership could not be confirmed. 相似文献
42.
Construction of large aperture free-standing metal wire grids is demonstrated for the lower end of the millimeter wave spectral region. For the constructed two grids the co-polarized and cross-polarized components of transmitted power were measured at 45° oblique incidence. The measurements were performed as a function of wire orientation angle and in more detail at selected angles. The results are in good agreement with the theoretical results presented in the literature. In order to save time and costs the construction apparatus was simplified from those reported previously by other authors. It was shown that for this frequency range the grid characteristics are not degraded when such an apparatus is applied. One of the constructed grids will be used in a calibration system of the Helsinki University of Technology (HUT) polarimetric radiometer. 相似文献
43.
Tanja Winkler 《International Planning Studies》2009,14(1):7-24
The international development community invests bulk of its financial aid to South Africa in establishing procedural conditions through which development actions may be realized. Accordingly, ‘democracy assistance’ is designed to target governmental structures and civil society organizations (CSOs). International donor governments and aid agencies also assign an operational role to civil society so that it may assist in the process of change. However, an overt emphasis on the procedural aspects of democracy, governance, and development ignores the context and object of planning. Consequently, development planning in South Africa is perceived in narrow procedural terms alone, and not in terms of more holistic and equitable development responses. 相似文献
44.
Nina Krako Jakovljevic Kasja Pavlovic Aleksandra Jotic Katarina Lalic Milica Stoiljkovic Ljiljana Lukic Tanja Milicic Marija Macesic Jelena Stanarcic Gajovic Nebojsa M. Lalic 《International journal of molecular sciences》2021,22(12)
Type 2 diabetes (T2D), one of the most prevalent noncommunicable diseases, is often preceded by insulin resistance (IR), which underlies the inability of tissues to respond to insulin and leads to disturbed metabolic homeostasis. Mitochondria, as a central player in the cellular energy metabolism, are involved in the mechanisms of IR and T2D. Mitochondrial function is affected by insulin resistance in different tissues, among which skeletal muscle and liver have the highest impact on whole-body glucose homeostasis. This review focuses on human studies that assess mitochondrial function in liver, muscle and blood cells in the context of T2D. Furthermore, different interventions targeting mitochondria in IR and T2D are listed, with a selection of studies using respirometry as a measure of mitochondrial function, for better data comparison. Altogether, mitochondrial respiratory capacity appears to be a metabolic indicator since it decreases as the disease progresses but increases after lifestyle (exercise) and pharmacological interventions, together with the improvement in metabolic health. Finally, novel therapeutics developed to target mitochondria have potential for a more integrative therapeutic approach, treating both causative and secondary defects of diabetes. 相似文献
45.
Werten Marc W. T.; Wisselink Wouter H.; Jansen-van den Bosch Tanja J.; de Bruin Eric C.; de Wolf Frits A. 《Protein engineering, design & selection : PEDS》2001,14(6):447-454
A custom-designed, highly hydrophilic gelatin was produced in
Pichia pastoris
. Secreted production levels in single-copytransformants were in the range 36 g/l of clarified brothand purification to near homogeneity could be accomplished bydifferential ammonium sulfate precipitation. Despite the factthat gelatins are highly susceptible to proteolysis becauseof their unfolded structure, the recombinant protein was shownto be fully intact by SDSPAGE, N-terminal sequencing,gel filtration chromatography and mass spectrometry. Owing toits highly hydrophilic nature, the migration of the syntheticgelatin in SDSPAGE was severely delayed. Esterificationof the carboxylic amino acid side chains resulted in normalmigration. The high polarity of the synthetic gelatin also accountsfor its negligible surface activity in water at concentrationsup to 5% (w/v), as determined by tensiometry. Circular dichroismspectrometry showed that the non-hydroxylated gelatin did notform triple helices at 4°C. The spectrum was even more representativeof the random coil conformation than the spectrum of naturalnon-hydroxylated gelatins. 相似文献
46.
Alexander Paasche Markus Schiller Dr. Tanja Schirmeister Prof. Dr. Bernd Engels Prof. Dr. 《ChemMedChem》2010,5(6):869-880
We investigated the reactions between substituted α,β‐unsaturated carbonyl compounds (Michael systems) and thiols by computations as well as chemoassays. The results give insight into variations in the underlying mechanisms as a function of the substitution pattern. This is of interest for the mechanisms of inhibition of the SARS coronavirus main protease (SARS‐CoV Mpro) by etacrynic acid derivatives as well as for the excess toxicity of substituted α,β‐unsaturated carbonyl compounds. This study compares possible reaction courses including 1,4‐addition followed by a ketonization step, and underscores the importance of a base‐catalyzed step for the reactivity of thiol groups in enzymes. Phenyl and methyl substituents at the Michael system decrease the reactivity of the electrophilic compound, but chlorophenyl substituents partly recover the reactivity. Computations also indicate that electron‐pushing substituents lead to a change in the reaction mechanism. The conformation of the Michael system is also found to significantly influence reactivity: the s‐cis conformation leads to higher reactivity than the s‐trans conformation. The computed data explain the trends in measured inhibition potencies of substituted α,β‐unsaturated carbonyl compounds and of reaction rates in chemical assays. They also indicate that the reversibility of inhibition does not stand in contrast to the formation of a new covalent bond between inhibitor and protease. 相似文献
47.
Stefan Strobl Peter Supancic Tanja Lube Robert Danzer 《Journal of the European Ceramic Society》2012,32(8):1491-1501
The Newman and Raju formula for the stress intensity factor of a semi-elliptical surface crack loaded in uniaxial tension or in bending has been developed about 30 years ago using an FE-analysis for several geometric parameters and fitting an empirical equation to the data points. The Poisson's ratio analyzed was 0.3.In this paper a reassessment of the Newman and Raju formula is made, where all relevant geometric parameters of crack and specimen and the Poisson's ratio are considered. The deviations of the old formula from the new results are up to 21%, if the full range of Poisson's ratio is taken into account. Furthermore the influence of the crack-surface intersection angle is discussed.The results of this work are important for more precise fracture toughness measurements in brittle materials and give a practical guidance for appropriate specimen preparation for fracture toughness measurements, which is also considered here. 相似文献
48.
Tanja Zseby Joachim Fabini Dipika Rani 《e & i Elektrotechnik und Informationstechnik》2014,131(1):8-13
Synchronized phasor measurements provide the basis for fine-grained wide area power quality monitoring in electric grids. Time-synchronized phasor measurement units (PMUs) are deployed at different locations in the grid and report 10–60 measurements/second to energy management systems or other applications. For control applications it is crucial to receive measurement data as soon as possible after a state change in order to trigger corrective actions in time to prevent incidents in the grid. In this paper we analyze characteristics of synchrophasor M2M communication for different network technologies, including VDSL, HSPA and LTE networks. We briefly review synchrophasor communication approaches and real-time demands. We then emulate PMU traffic and perform measurements on different networks. We show how the underlying technology influences one-way delay patterns for synchrophasor communication, which has direct implication on the achievable real-time properties. 相似文献
49.
Contemporary urban policies in various liberal democracies are purposefully crafted to foster both economic efficiency and social justice. For Barel (1989), achieving these directives constitutes a ‘paradox’. Yet, as argued here, this paradox is not new. Rather, it is rooted in liberalism, which, in turn, shapes mainstream planning practices and modes of government. This paper therefore turns to the ‘ethico-politics’ of planning in order to demonstrate how the City of Johannesburg articulates its economic growth and social responsibility policies. It is proposed that unless planners challenge the often unquestioned liberal norms of planning, entrenched norms will continue to obscure alternative possibilities. 相似文献
50.