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排序方式: 共有724条查询结果,搜索用时 750 毫秒
1.
Dr. Adarshi P. Welegedara Dr. Ansis Maleckis Ruchira Bandara Dr. Mithun C. Mahawaththa Iresha Dilhani Herath Yi Jiun Tan Dr. Angeliki Giannoulis Prof. Daniella Goldfarb Prof. Gottfried Otting Prof. Thomas Huber 《Chembiochem : a European journal of chemical biology》2021,22(8):1480-1486
The selenol group of selenocysteine is much more nucleophilic than the thiol group of cysteine. Selenocysteine residues in proteins thus offer reactive points for rapid post-translational modification. Herein, we show that selenoproteins can be expressed in high yield and purity by cell-free protein synthesis by global substitution of cysteine by selenocysteine. Complete alkylation of solvent-exposed selenocysteine residues was achieved in 10 minutes with 4-chloromethylene dipicolinic acid (4Cl-MDPA) under conditions that left cysteine residues unchanged even after overnight incubation. GdIII−GdIII distances measured by double electron–electron resonance (DEER) experiments of maltose binding protein (MBP) containing two selenocysteine residues tagged with 4Cl-MDPA-GdIII were indistinguishable from GdIII−GdIII distances measured of MBP containing cysteine reacted with 4Br-MDPA tags. 相似文献
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Of 101 women, 15-50 years of age, presenting with vaginal discharge, 34 had bacterial vaginosis and were randomly assigned to a seven-day course of oral treatment with either erythromycin (0.5 g b.i.d.) or metronidazole (0.4 g b.i.d.) in a single-blind, cross-over study. Treatment failure (> or = three clinical signs of bacterial vaginosis) occurred in 13 (81%) of 16 patients given erythromycin, as compared with three (17%) of 18 women treated with metronidazole (p < 0.001). Persistence of Gardnerella vaginalis, Mobiluncus species and/or Mycoplasma hominis was found in 14 of 16 patients treated with erythromycin, and in four of 16 patients treated with metronidazole. Treatment with metronidazole was successful (< or = two clinical signs of bacterial vaginosis) in eight of 10 cases of erythromycin treatment failure. Neither of two cases of metronidazole treatment failure was cured with erythromycin. At three-month follow-up of 31 women, persistence or recurrence of bacterial vaginosis was diagnosed in 11 cases (36%). 相似文献
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International scientific collaboration is very sensitive to political and economic changes in a country or a geopolitical region. Collaboration in research is reflected by the corresponding coauthorship of the published results which can be analysed with the help of bibliometric methods. Based on data from theScience Citation Index (SCI), the change of annual international coauthorship patterns ofBulgaria, Czechoslovakia, Hungary, Poland andRomania have been analysed for the periods 1981–1985 and 1984–1993, respectively. It is shown that international collaboration was not developing similarly in the countries under study. Whilst scientific communities of Hungary and Poland have already been opening in the early 80s, the international collaboration of the other East-European countries was still dominated by COMECON relations till 1989. As expected, since 1990 an increasing scientific collaboration with highly developed countries can be observed in all five countries. At the same time, scientific collaboration with the former communist countries shows a clear decline. The great share of international co-authorship links is some countries reflect various tendencies part of which are interpreted with the help of a cardiologic model. 相似文献
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Gottfried Spicher 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(4):300-303
Zusammenfassung Es wurden Untersuchungen angestellt über die Mikroflora von 26 Weizensauerteigen für die Panettone- und Weizenbrotherstellung aus Bäckereien in Italien, der Schweiz, Deutschland und Schweden. Die Sauerteige wurden teils mit einem Spontansauer angestellt, teils mit einem reifen Weizensauer (masa madre), der bereits über längere Zeit fortgeführt wurde. Die Mikroflora der Sauerteige (pH 4,4 bis 3,8, Säuregrad 6,3 bis 22,4) setzte sich aus 2,5 × 105 bis 3 × 109 Lactobacillun/g und 1 × 103 bis 4,5 × 107 Hefen/g zusammen. Es wurden insgesamt 388 Isolate gewonnen und als Vertreter der GattungLactobacillus identifiziert. In Weizensauerteigen, die mit einem Spontansauer angestellt wurden, traten vornehmlich homofermentativeLactobacillus-Species auf (Lactobacillus plantarum, L. casei, L. farciminis, L. homohiochii), nebenL. brevis, L. hildegardii und einigen anderen heterofermentativen Spezies. Die Sauerteigbakterien des mit einem masa madre angestellten Weizensauerteig erwiesen sich insbesondere alsLactobacillus brevis ssp.lindneri resp.L. sanfrancisco, nebenL. brevis, L. hildegardii undL. viridescens. Daneben kamen in den Weizensauerteigen zu mehr oder minder hohen AnteilenStreptococcus spp. vor. Bei den im Weizensauerteig auftretenden Hefen handelt es sich umSaccharomyces cerevisiae, nebenS. servazzi undCandida milleri.
Nr. 5475 der Veröffentlichung der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung, Detmold 相似文献
The microflora of sourdoughXXII. Communication: The lactobacillus species of wheat sourdough
Summary We investigated the microflora of 26 wheat sourdoughs which are used for the production of panettone and wheat bread in bakeries in Italy, Switzerland, Germany and Sweden. The sourdoughs were started in part with a ripe wheat sour (masa madre) which had been propagated for a long time. The microflora of the wheat sourdough (pH 4.4 to 3.8; acidity 6.3 to 22.4) consisted of 2 × 105 to 3 × 109 lactobacilli/g and 1 × 103 to 4.5 to 107 yeasts/g. We obtained 388 isolates; all belonging to the genusLactobacillus. In wheat sourdoughs which were started with a spontaneous sour homofermentativelactobacilli (Lactobacillus plantarum, L. casei, L. farciminis, L. homohiochii) are mainly found and alsoLactobacillus brevis, L. hildegardii and some other heterofermentative species. The main sourdough bacteria of wheat sourdoughs which were prepared with a masa madre were identified asLactobacillus brevis ssp.lindneri resp.L. sanfrancisco, which were present in addition toL. brevis, L. hildegardii, andL. viridescens. We also found varying numbers ofStreptococcus spp. in the wheat sourdoughs. The yeasts which we identified wereSaccharomyces cerevisiae, S. servazzi andCandida milleri.
Nr. 5475 der Veröffentlichung der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung, Detmold 相似文献
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Roland Schmidt Ulrich Hammon Stefan Gottfried M. Bruce Welch Helmut G. Alt 《应用聚合物科学杂志》2003,88(2):476-482
The synthesis of iron(II) complexes with various tridentate di(imino)pyridine ligands and their potential as ethene oligomerization catalysts are described. The ligands are characterized by 1H‐ and 13C‐NMR spectroscopy and the complexes only by mass spectrometry due to their paramagnetism. After activation either with methylalumoxane (MAO) or with a heterogeneous cocatalyst consisting of partially hydrolyzed trimethylaluminum and silica gel, the prepared complexes proved to be good catalysts for the oligomerization of ethene. 1‐Octene, 1‐hexene, and 1‐decene were the major products, formed in very high isomeric purity (99.9 %). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 476–482, 2003 相似文献
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Janine Glänzel Arnd Meyer Roman Unger Michael Bräunig Volker Wittstock Steffen Ihlenfeldt 《The International Journal of Advanced Manufacturing Technology》2017,88(5-8):1279-1288
A new interdisciplinary approach is discribed to identifying unknown parameters using an extended version of the known interval bisection method. This developed method is based on the use of finite elements for calibrating the simulation calculation. The resulting thermo-elastic deformations which occur in drilling processes with impaired cooling lubrication are to be used as correction values for tool positioning in the NC control. Based on the strong impact on workpiece temperature of machining, a simulation approach is presented for calculating the temperature fields and their thermo-elastic consequences. In addition, methods are presented to correct these effects. This paper particularly deals with the temperature fields of drilling operations. Special attention is paid to the technique employed for iterative numerical determination of the unknown heat flux η w and heat transfer coefficient \(\bar {\gamma }\) values. Finally, the data obtained from experiments are compared with those achieved by numerical simulation in order to verify the efficiency of simulation and determination of parameters. 相似文献
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Felix Schmutzler Christopher Zschiesche Juliane Titus David Poppitz Jens Freiding Rainer Rakoczy Andreas Reitzmann Roger Gläser 《化学,工程师,技术》2021,93(6):981-989
The hydroisomerization of two long-chain n-alkane mixtures was investigated over bifunctional Pt/H-ZSM-5 catalysts before and after dealumination of preshaped zeolite/binder pellets. The hydroisomerization over the dealuminated catalysts leads to more isomers and less cracking products. Consequently, higher ratios of multi- to mono-branched isomerization products are formed as expected for large- rather than medium-pore zeolites. This indicates a higher availability of space in the vicinity of the active sites and provides an attractive route to make medium-pore zeolites suitable for upgrading higher boiling hydrocarbon feeds. 相似文献
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