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81.
Shaun Hay Kenton Thiessen Dagmar Svecova Baidar Bakht 《Canadian Metallurgical Quarterly》2006,10(6):483-491
The objective of this study was to develop a cost-effective shear-strengthening technique for timber stringers that is environmentally friendly and leads to a durable structure. Testing was performed on creosote-treated Douglas fir beams, with dimensions of 100×400×3,650?mm, removed from a 40 year old bridge. Two strengthening schemes were investigated; incorporating vertical and diagonal glass fiber-reinforced polymer (GFRP) sheets applied to both shear spans. The diagonal scheme proved effective in increasing the average ultimate load, flexural stiffness, and deformability of the beams. Performance of the members reinforced using the vertical scheme, however, was poor compared to diagonally reinforced beams. The contribution of the diagonal sheets to the shear capacity of the stringers was around 12% at service loads and 40% at ultimate load. In conclusion, this study has shown that diagonal GFRP sheets are more effective than vertical sheets in shear-strengthening timber stringers with horizontal splits at their ends. 相似文献
82.
Sternad Dagmar; Duarte Marcos; Katsumata Hiromu; Schaal Stefan 《Canadian Metallurgical Quarterly》2001,27(5):1163
Rhythmically bouncing a ball with a racket was investigated and modeled with a nonlinear map. Model analyses provided a variable defining a dynamically stable solution that obviates computationally expensive corrections. Three experiments evaluated whether dynamic stability is optimized and what perceptual support is necessary for stable behavior. Two hypotheses were tested: (a) Performance is stable if racket acceleration is negative at impact, and (b) variability is lowest at an impact acceleration between -4 and -1 m/s2. In Experiment 1 participants performed the task, eyes open or closed, bouncing a ball confined to a 1-dimensional trajectory. Experiment 2 eliminated constraints on racket and ball trajectory. Experiment 3 excluded visual or haptic information. Movements were performed with negative racket accelerations in the range of highest stability. Performance with eyes closed was more variable, leaving acceleration unaffected. With haptic information, performance was more stable than with visual information alone. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
83.
84.
Alena Nprstkov Kateina Malínsk Lenka Zvesk Drbkov Elodie Billey Dagmar Nprstkov Eva Sýkorov Ccile Bousquet-Antonelli David Honys 《International journal of molecular sciences》2021,22(4)
ALBA DNA/RNA-binding proteins form an ancient family, which in eukaryotes diversified into two Rpp25-like and Rpp20-like subfamilies. In most studied model organisms, their function remains unclear, but they are usually associated with RNA metabolism, mRNA translatability and stress response. In plants, the enriched number of ALBA family members remains poorly understood. Here, we studied ALBA dynamics during reproductive development in Arabidopsis at the levels of gene expression and protein localization, both under standard conditions and following heat stress. In generative tissues, ALBA proteins showed the strongest signal in mature pollen where they localized predominantly in cytoplasmic foci, particularly in regions surrounding the vegetative nucleus and sperm cells. Finally, we demonstrated the involvement of two Rpp25-like subfamily members ALBA4 and ALBA6 in RNA metabolism in mature pollen supported by their co-localization with poly(A)-binding protein 3 (PABP3). Collectively, we demonstrated the engagement of ALBA proteins in male reproductive development and the heat stress response, highlighting the involvement of ALBA4 and ALBA6 in RNA metabolism, storage and/or translational control in pollen upon heat stress. Such dynamic re-localization of ALBA proteins in a controlled, developmentally and environmentally regulated manner, likely reflects not only their redundancy but also their possible functional diversification in plants. 相似文献
85.
Dagmar Ammelt Alica Lammerskitten Artur Wiktor Francisco J. Barba Stefan Toepfl Oleksii Parniakov 《International Journal of Food Science & Technology》2021,56(4):1777-1787
The effect of pulsed electric fields (PEF) on the cell disintegration index (Zp), the freeze-drying process and the final product quality of red beet and pineapple tissue was studied. Red beets and pineapples were PEF-treated at an electric field strength of 1.07 kV/cm and specific energy inputs of 1 kJ/kg and 4 kJ/kg (PEF1 and PEF2, respectively). Freeze-drying was performed at a pressure of 1 mbar and heating plate temperature of 50 °C for red beet and 40 °C for pineapple. The quality of freeze-dried tissue was evaluated by the analysis of residual moisture content, macrostructure, texture, colour and rehydration properties. For freeze-dried red beets, the betalain content from extracts was studied. It could be stated that PEF pre-treatment had no significant influence on drying time reduction, however significantly improved the final quality of freeze-dried product. Moreover, the effect of PEF was strongly depending on type of plant material used. 相似文献
86.
The role of phase-transfer catalysts (PTC) (ammonium and phosphonium salts) with various anions on the biphasic oxidative cleavage of long chain olefins with aqueous hydrogen peroxide catalyzed by Na2WO4/H3PO4/PTC system has been investigated. It was shown that the nature of PTC widely affects the catalytic activity of the above system in the conversion of alkenes, cycloalkenes and unsaturated fatty acids into carboxylic acids.
相似文献87.
Biosynthesis of the Fluorinated Natural Product Nucleocidin in Streptomyces calvus Is Dependent on the bldA‐Specified Leu‐tRNAUUA Molecule 下载免费PDF全文
Xi Ming Zhu Stefanie Hackl Dr. Maulik N. Thaker Dr. Lindsay Kalan Claudia Weber Dr. Dagmar S. Urgast Dr. Eva M. Krupp Alyssa Brewer Stephanie Vanner Anjuli Szawiola Grace Yim Prof. Jörg Feldmann Prof. Andreas Bechthold Prof. Gerard D. Wright Prof. David L. Zechel 《Chembiochem : a European journal of chemical biology》2015,16(17):2498-2506
Nucleocidin is one of the very few natural products known to contain fluorine. Mysteriously, the nucleocidin producer Streptomyces calvus ATCC 13382 has not been observed to synthesize the compound since its discovery in 1956. Here, we report that complementation of S. calvus ATCC 13382 with a functional bldA‐encoded Leu‐tRNAUUA molecule restores the production of nucleocidin. Nucleocidin was detected in culture extracts by 19F NMR spectroscopy, HPLC‐ESI‐MS, and HPLC‐continuum source molecular absorption spectroscopy for fluorine‐specific detection. The molecule was purified from a large‐scale culture and definitively characterized by NMR spectroscopy and high‐resolution MS. The nucleocidin biosynthetic gene cluster was identified by the presence of genes encoding the 5′‐O‐sulfamate moiety and confirmed by gene disruption. Two of the genes within the nucleocidin biosynthetic gene cluster contain TTA codons, thus explaining the dependence on bldA and resolving a 60‐year‐old mystery. 相似文献
88.
Cover Picture: Freezing the Bioactive Conformation to Boost Potency: The Identification of BAY 85‐8501, a Selective and Potent Inhibitor of Human Neutrophil Elastase for Pulmonary Diseases (ChemMedChem 7/2015) 下载免费PDF全文
Dr. Franz von Nussbaum Dr. Volkhart M.‐J. Li Dr. Swen Allerheiligen Sonja Anlauf Dr. Lars Bärfacker Dr. Martin Bechem Dr. Martina Delbeck Dr. Michael Gerisch Dr. Heike Gielen‐Haertwig Dr. Helmut Haning Dagmar Karthaus Dr. Dieter Lang Dr. Klemens Lustig Dr. Daniel Meibom Prof. Dr. Joachim Mittendorf Dr. Martina Schäfer Dr. Jens Schamberger Dr. Adrian Tersteegen 《ChemMedChem》2015,10(7):1117-1117
89.
Shang L Azadfar N Stockmar F Send W Trouillet V Bruns M Gerthsen D Nienhaus GU 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(18):2614-2620
A facile strategy to synthesize water-soluble fluorescent gold nanoclusters (Au NCs) stabilized with the bidentate ligand dihydrolipoic acid (DHLA) is reported. The DHLA-capped Au NCs are characterized by UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The Au NCs possess many attractive features including ultrasmall size, bright near-infrared luminescence, high colloidal stability, and good biocompatibility, making them promising imaging agents for biomedical and cellular imaging applications. Moreover, their long fluorescence lifetime (>100 ns) makes them attractive as labels in fluorescence lifetime imaging (FLIM) applications. As an example, the internalization of Au NCs by live HeLa cells is visualized using the FLIM technique. 相似文献
90.
Li Shang Linxiao Yang Jürgen Seiter Marita Heinle Gerald Brenner‐Weiss Dagmar Gerthsen G. Ulrich Nienhaus 《Advanced Materials Interfaces》2014,1(2)
Despite intense research on biological and biomedical applications of nanoparticles, our understanding of their basic interactions with the biological environment is still incomplete. Systematic variation of the physicochemical properties of the nanoparticles is widely seen as a promising strategy to obtain further insights. In view of the key role of the protein adsorption layer forming on nanoparticles in contact with biofluids, we systematically varied the surface charge of proteins adsorbing onto nanoparticles by chemical modification so as to examine the effect of Coulomb forces in modulating nano‐bio interactions. We chose human serum albumin (HSA) as a model protein and ultra‐small, negatively charged fluorescent gold nanoclusters (AuNCs) as model nanoparticles. By using fluorescence and CD spectroscopies, we measured binding affinities and structural changes upon binding of the HSA variants. The strengths of the protein‐nanoparticle interactions were found to change substantially upon modifying the surface charge of HSA. Furthermore, by using inductively coupled plasma optical emission spectroscopy, confocal fluorescence microscopy, scanning transmission electron microscopy and cell viability assays, we observed that cellular interactions of the AuNCs, including their adherence to cell membranes, uptake efficiency and cytotoxicity, depended markedly on the different surface charges of the HSA variants adsorbed onto the nanoparticles. These results illustrate vividly that the cellular responses to nanoparticle exposure depend on the specific properties of the proteins that adsorb onto nanoparticles from biofluids. 相似文献