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排序方式: 共有760条查询结果,搜索用时 15 毫秒
61.
62.
Horst Karl Ines Lehmann Hartmut Rehbein & Reinhard Schubring 《International Journal of Food Science & Technology》2010,45(1):56-66
A range of conventionally and organically farmed Pangasius or sutchi catfish fillets available on the German market were analysed to compare both composition and quality. Differentiation of Pangasius hypophthalmus from Pangasius bocourti was achieved by RFLP-SSCP analysis. The protein content of conventionally farmed fillets ranged between 13.3 and 15.7%, whereas organically produced fillets had significantly higher protein contents of between 17.0 and 17.4%. No difference in the fat content between farming methods was observed, which varied between 1.4 and 3.2%. Polyunsaturated fatty acids represented about 24% of the total fatty acids with a high level of linoleic acid. The comparison of the proximate composition indicated that water was added to most of the conventionally farmed products, in different amounts, as well as water-binding capacity enhancing additives. Differential scanning calorimetry was used to demonstrate the presence of polyphosphate on muscle proteins. Differences in texture, water-binding capacity and colour are discussed. 相似文献
63.
Filipa Bezerra Christoph Niemietz Hartmut H. J. Schmidt Andree Zibert Shuling Guo Brett P. Monia Paula Gonalves Maria Joo Saraiva Maria Rosrio Almeida 《International journal of molecular sciences》2021,22(17)
Transthyretin (TTR) proteolysis has been recognized as a complementary mechanism contributing to transthyretin-related amyloidosis (ATTR amyloidosis). Accordingly, amyloid deposits can be composed mainly of full-length TTR or contain a mixture of both cleaved and full-length TTR, particularly in the heart. The fragmentation pattern at Lys48 suggests the involvement of a serine protease, such as plasmin. The most common TTR variant, TTR V30M, is susceptible to plasmin-mediated proteolysis, and the presence of TTR fragments facilitates TTR amyloidogenesis. Recent studies revealed that the serine protease inhibitor, SerpinA1, was differentially expressed in hepatocyte-like cells (HLCs) from ATTR patients. In this work, we evaluated the effects of SerpinA1 on in vitro and in vivo modulation of TTR V30M proteolysis, aggregation, and deposition. We found that plasmin-mediated TTR proteolysis and aggregation are partially inhibited by SerpinA1. Furthermore, in vivo downregulation of SerpinA1 increased TTR levels in mice plasma and deposition in the cardiac tissue of older animals. The presence of TTR fragments was observed in the heart of young and old mice but not in other tissues following SerpinA1 knockdown. Increased proteolytic activity, particularly plasmin activity, was detected in mice plasmas. Overall, our results indicate that SerpinA1 modulates TTR proteolysis and aggregation in vitro and in vivo. 相似文献
64.
Doris Pospiech Andreas Korwitz Kathrin Eckstein Hartmut Komber Dieter Jehnichen Marcus Suckow Albena Lederer Kerstin Arnhold Michael Göbel Martina Bremer Anton Hoffmann Steffen Fischer Anett Werner Thomas Walther Harald Brünig Brigitte Voit 《应用聚合物科学杂志》2019,136(46):48257
Thermotropic liquid crystalline polyesters with varied chemical structure are synthesized by melt transesterification polycondensation. They are employed as matrix for blends with lignin materials to obtain melt-spinnable precursors for carbon fibers. The lignin samples are carefully purified by fractionation, enzymatic removal of reducing sugars, and subsequent modification of the terminal OH groups. Effective melt blending is achieved with liquid-crystalline aromatic–aliphatic polyesters having melting ranges that match the softening temperature of the lignin fractions, which is necessary to prevent thermal decomposition of the lignin. Polyester/lignin blends are partially compatibilized, phase-separated materials. The polyester/lignin materials are melt-spun successfully. The fiber properties depend on the lignin purification process. X-ray scattering reveals that orientation in lignin-containing fibers is maintained. First experiments show that the fibers can be converted successfully to carbon fibers by thermal annealing procedures. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48257. 相似文献
65.
Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy 下载免费PDF全文
Dr. Madhu Nagaraj Dr. Trent W. Franks Siavash Saeidpour Dr. Tobias Schubeis Dr. Hartmut Oschkinat Dr. Christiane Ritter Dr. Barth‐Jan van Rossum 《Chembiochem : a European journal of chemical biology》2016,17(14):1308-1311
Dynamic nuclear polarization (DNP) NMR can enhance sensitivity but often comes at the price of a substantial loss of resolution. Two major factors affect spectral quality: low‐temperature heterogeneous line broadening and paramagnetic relaxation enhancement (PRE) effects. Investigations by NMR spectroscopy, isothermal titration calorimetry (ITC), and EPR revealed a new substantial affinity of TOTAPOL to amyloid surfaces, very similar to that shown by the fluorescent dye thioflavin‐T (ThT). As a consequence, DNP spectra with remarkably good resolution and still reasonable enhancement could be obtained at very low TOTAPOL concentrations, typically 400 times lower than commonly employed. These spectra yielded several long‐range constraints that were difficult to obtain without DNP. Our findings open up new strategies for structural studies with DNP NMR spectroscopy on amyloids that can bind the biradical with affinity similar to that shown towards ThT. 相似文献
66.
Julia?CooperEmail author Eleanor?Y.?Reed Stefan?H?rtenhuber Thomas?Lindenthal Anne-Kristin?L?es Paul?M?der Jakob?Magid Astrid?Oberson Hartmut?Kolbe Kurt?M?ller 《Nutrient Cycling in Agroecosystems》2018,110(2):227-239
Maintaining sufficient soil phosphorus (P) levels for non-limiting crop growth is challenging in organic systems since off-farm inputs of P are restricted. This study assessed the status of P on organic farms in Europe using soil test results for extractable P. Data was obtained from published literature, unpublished theses, and various national and regional databases of soil test values. Most of the data (15,506 observations) came from field scale soil tests, but in some cases (1272 observations) values had been averaged across a farm. Farm scale and field scale data were analysed separately and the impact of farm type (arable, dairy, grassland, horticulture, mixed, poultry, unknown) was assessed. Soil test results were assigned to P classes from very low (P class 1) to very high (P class 5). The farm scale data came primarily from Norway, Sweden and Switzerland and did not indicate deficiencies in extractable P; 93% of farms fell into class 3 or above. The majority of the field scale data came from Germany and indicated sufficient or higher levels of P availability for arable and grassland systems on 60% of fields; the remaining fields had low or very low available P. Adaptations in organic systems may improve P uptake and utilization efficiency allowing yields to be maintained in the short-term, nevertheless there is cause for concern about the long-term P sustainability of some organic farming systems in Europe. This highlights the need to reassess allowable P inputs in organic farming systems to improve overall sustainability. 相似文献
67.
Fließkurven beschreiben das Formänderungsvermögen von Werkstoffen. Gleichzeitig liefern sie Informationen über die Wechselwirkung zwischen der Ver- und Entfestigung, wobei diese beiden Eigenschaften temperaturabhängig sind. Fließkurven wurden an Stählen aufgenommen, die sich im wesentlichen in ihrem Kohlenstoffgehalt unterscheiden. Die Bestimmung der Formänderungsfähigkeit erfolgte bei Temperaturen, die denen entsprechen, bei denen eine Austenitformhärtung vorgenommen wird. Die mathematische Beschreibung der Fließkurven läßt erkennen, daß zunächst mit steigender Umformtemperatur die Verfestigungsrate abnimmt. Der Kohlenstoffgehalt erhöht dagegen die Verfestigungsrate. Die dynamische Erholung wird mit wachsender Umformtemperatur beschleunigt, ebenso mit steigendem Kohlenstoffgehalt. 相似文献
68.
69.
We consider the problem of collectively locating a set of points within a set of disjoint polygonal regions when neither for points nor for regions preprocessing is allowed. This problem arises in geometric database systems. More specifically it is equivalent to computing theinside join of geo-relational algebra, a conceptual model for geo-data management. We describe efficient algorithms for solving this problem based on plane-sweep and divide-and-conquer, requiringO(n(logn) +t) andO(n(log2 n) +t) time, respectively, andO(n) space, wheren is the total number of points and edges, and (is the number of reported (point, region) pairs. Since the algorithms are meant to be practically useful we consider as well as the internal versions-running completely in main memory-versions that run internally but use much less than linear space and versions that run externally, that is, require only a constant amount of internal memory regardless of the amount of data to be processed. Comparing plane-sweep and divide-and-conquer, it turns out that divide-and-conquer can be expected to perform much better in the external case even though it has a higher internal asymptotic worst-case complexity. An interesting theoretical by-product is a new general technique for handling arbitrarily large sets of objects clustered on a singlex-coordinate within a planar divide-and-conquer algorithm and a proof that the resulting “unbalanced” dividing does not lead to a more than logarithmic height of the tree of recursive calls. 相似文献
70.
Zusammenfassung Angeregt durch Robert W. Floyds Turing-Award-Lecture ,,The Paradigms of Programming“ von 1979 [6] und motiviert durch die
Unzufriedenheit des Praktikers mit dem Stand der Softwaretechnik aus vielen Industrieprojekten, versucht dieser Beitrag eine
Bestandsaufnahme der Programmiertechnik und identifiziert die Defizite aus Sicht der Grundprinzipien des Konstruktionsprozesses.
Mit der Objektorientierung sind, besonders in den letzten Jahren, viele neue Programmiersprachen entstanden, die sowohl Wert
auf schnelle Entwicklungszyklen als auch auf Erweiterbarkeit legen. Die heute haupts?chlich verwendeten Sprachen und Umgebungen
sind von diesen Zielen weit entfernt. Das Entwickeln von Software ist zum einen zu kompliziert und zum anderen schmerzt die
,,semantische Lücke“ zwischen den ausdrückbaren und den erforderlichen Konzepten. Neue, viel versprechende Programmiersprachen,
die sich durchweg auf Metaprogrammierung stützen, um die erforderliche semantische Erweiterbarkeit der Sprachen zu erreichen,
deuten die Richtung zukünftiger Entwicklungen an. 相似文献