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排序方式: 共有774条查询结果,搜索用时 15 毫秒
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Hermann G. Hauthal Peter Jürges Lothar Möhle Udo Ohlerich 《Journal of surfactants and detergents》1999,2(2):175-180
It has been shown that ternary surfactant synergism can be predicted on the basis of nonideality parameters of binary subsystems
derived from advancing contact angles. Studies with appropriate surfactant mixtures of glucamides, ether sulfates, secondary
alkane sulfonates, and alkylamidopropyl betaines were performed on substrates of different polarity. 相似文献
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Competitive advantage in the information age is based, in large part, on a firm's capability to acquire and use quality information as well as effective and efficient services, with its information technology resources at the least possible cost. One possible strategy for improving the cost-performance ratio of information technology resources is known as downsizing. The downsizing effort is a strategic move that is believed by many organizations to be capable of yielding significant benefits. It can also be a costly endeavour which may leave a firm worse off. Therefore, careful planning and control must be exercised if information systems downsizing is to succeed. This paper reports the results of a study whose purpose is to identify and explain the critical success factors for a downsizing effort. Results of the study show that information systems downsizing may produce benefits such as improved information systems, improved organizational structure, higher productivity, and lower cost. The results also indicate that downsizing success is dependent upon complex linkages of communications, action plans, needs for downsizing as perceived by employees, and the specific method of downsizing used. 相似文献
35.
Huixia Yang Zhi Ma Lin Peng Christina Kuhn Martina Rahmeh Sven Mahner Udo Jeschke Viktoria von Schnfeldt 《International journal of molecular sciences》2021,22(16)
Epigenetics play a vital role in early embryo development. Offspring conceived via assisted reproductive technologies (ARTs) have a three times higher risk of epigenetic diseases than naturally conceived children. However, investigations into ART-associated placental histone modifications or sex-stratified analyses of ART-associated histone modifications remain limited. In the current study, we carried out immunohistochemistry, chip-sequence analysis, and a series of in vitro experiments. Our results demonstrated that placentas from intra-cytoplasmic sperm injection (ICSI), but not in vitro fertilization (IVF), showed global tri-methylated-histone-H3-lysine-4 (H3K4me3) alteration compared to those from natural conception. However, for acetylated-histone-H3-lysine-9 (H3K9ac) and acetylated-histone-H3-lysine-27 (H3K27ac), no significant differences between groups could be found. Further, sex -stratified analysis found that, compared with the same-gender newborn cord blood mononuclear cell (CBMC) from natural conceptions, CBMC from ICSI-boys presented more genes with differentially enriched H3K4me3 (n = 198) than those from ICSI-girls (n = 79), IVF-girls (n = 5), and IVF-boys (n = 2). We also found that varying oxygen conditions, RNA polymerase II subunit A (Polr2A), and lysine demethylase 5A (KDM5A) regulated H3K4me3. These findings revealed a difference between IVF and ICSI and a difference between boys and girls in H3K4me3 modification, providing greater insight into ART-associated epigenetic alteration. 相似文献
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Sarah Meister Laura Hahn Susanne Beyer Corinna Paul Sophie Mitter Christina Kuhn Viktoria von Schnfeldt Stefanie Corradini Kritika Sudan Christian Schulz Theresa Maria Kolben Sven Mahner Udo Jeschke Thomas Kolben 《International journal of molecular sciences》2021,22(22)
The aim of this study was to analyze the expression of peroxisome proliferator-activated receptor γ (PPARγ) and retinoid X receptor α (RxRα), a binding heterodimer playing a pivotal role in the successful trophoblast invasion, in the placental tissue of preeclamptic patients. Furthermore, we aimed to characterize a possible interaction between PPARγ and H3K4me3 (trimethylated lysine 4 of the histone H3), respectively H3K9ac (acetylated lysine 9 of the histone H3), to illuminate the role of histone modifications in a defective trophoblast invasion in preeclampsia (PE). Therefore, the expression of PPARγ and RxRα was analyzed in 26 PE and 25 control placentas by immunohistochemical peroxidase staining, as well as the co-expression with H3K4me3 and H3K9ac by double immunofluorescence staining. Further, the effect of a specific PPARγ-agonist (Ciglitazone) and PPARγ-antagonist (T0070907) on the histone modifications H3K9ac and H3K4me3 was analyzed in vitro. In PE placentas, we found a reduced expression of PPARγ and RxRα and a reduced co-expression with H3K4me3 and H3K9ac in the extravillous trophoblast (EVT). Furthermore, with the PPARγ-antagonist treated human villous trophoblast (HVT) cells and primary isolated EVT cells showed higher levels of the histone modification proteins whereas treatment with the PPARγ-agonist reduced respective histone modifications. Our results show that the stimulation of PPARγ-activity leads to a reduction of H3K4me3 and H3K9ac in trophoblast cells, but paradoxically decreases the nuclear PPARγ expression. As the importance of PPARγ, being involved in a successful trophoblast invasion has already been investigated, our results reveal a pathophysiologic connection between PPARγ and the epigenetic modulation via H3K4me3 and H3K9ac in PE. 相似文献
39.
Florian Meierhofer Lutz Mädler Udo Fritsching 《American Institute of Chemical Engineers》2020,66(2):e16885
In flame spray pyrolysis (FSP), the evolution of metal oxide nanoparticles relies on quite a number of droplet (liquid) and vapor phase related physical mechanism as for instance precursor evaporation, oxidation, nucleation via gas-to-particle conversion mechanism, and subsequent particle (solid) growth mechanisms based on coagulation, sintering/coalescence, and agglomeration. The liquid precursor and dispersion oxygen feed rates are relevant control parameters of the FSP process for tailoring the nanoparticle size (diameter) and structure as well as the atomizer nozzle configuration. Sophisticated nonintrusive, laser-based in situ and ex situ diagnostics with multiscale spatial resolution (micrometer to meter range) are applied for analyzing droplet formation and size, gas velocity, temperature, species concentration, as well as primary and agglomerate diameters along the flow direction. Computational fluid dynamics (CFD) are coupled with population balance modeling (PBM) to elucidate the nanoparticle dynamics within the reactive spray. It is found that the CFD-PBM approach allows estimations of primary and agglomerate nanoparticle diameters within 80 and 75% accuracy compared to experimental data, suggesting that the methods presented could pave the way for designing next-generations of flame reactors. 相似文献
40.
Stefan Alexander Tennigkeit Raziye Karapinar Till Rudack Max-Aylmer Dreier Philipp Althoff Dennis Eickelbeck Tatjana Surdin Michelle Grömmke Melanie D. Mark Katharina Spoida Mathias Lübben Udo Höweler Prof. Dr. Stefan Herlitze Prof. Dr. Klaus Gerwert 《Chembiochem : a European journal of chemical biology》2019,20(14):1766-1771
The primary goal of optogenetics is the light-controlled noninvasive and specific manipulation of various cellular processes. Herein, we present a hybrid strategy for targeted protein engineering combining computational techniques with electrophysiological and UV/visible spectroscopic experiments. We validated our concept for channelrhodopsin-2 and applied it to modify the less-well-studied vertebrate opsin melanopsin. Melanopsin is a promising optogenetic tool that functions as a selective molecular light switch for G protein-coupled receptor pathways. Thus, we constructed a model of the melanopsin Gq protein complex and predicted an absorption maximum shift of the Y211F variant. This variant displays a narrow blue-shifted action spectrum and twofold faster deactivation kinetics compared to wild-type melanopsin on G protein-coupled inward rectifying K+ (GIRK) channels in HEK293 cells. Furthermore, we verified the in vivo activity and optogenetic potential for the variant in mice. Thus, we propose that our developed concept will be generally applicable to designing optogenetic tools. 相似文献