排序方式: 共有40条查询结果,搜索用时 15 毫秒
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Joseph Berry Tonio Buonassisi David A. Egger Gary Hodes Leeor Kronik Yueh‐Lin Loo Igor Lubomirsky Seth R. Marder Yitzhak Mastai Joel S. Miller David B. Mitzi Yaron Paz Andrew M. Rappe Ilan Riess Boris Rybtchinski Oscar Stafsudd Vladan Stevanovic Michael F. Toney David Zitoun Antoine Kahn David Ginley David Cahen 《Advanced materials (Deerfield Beach, Fla.)》2015,27(35):5102-5112
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Daniel Kalb Dr. Gerald Lackner Marcus Rappe Prof. Dr. Dirk Hoffmeister 《Chembiochem : a European journal of chemical biology》2015,16(10):1426-1430
L ‐α‐Aminoadipic acid reductases catalyze the ATP‐ and NADPH‐dependent reduction of L ‐α‐aminoadipic acid to the corresponding 6‐semialdehyde during fungal L ‐lysine biosynthesis. These reductases resemble peptide synthetases with regard to their multidomain composition but feature a unique domain of elusive function—now referred to as an adenylation activating (ADA) domain—that extends the reductase N‐terminally. Truncated enzymes based on NPS3, the L ‐α‐aminoadipic acid reductase of the basidiomycete Ceriporiopsis subvermispora, lacking the ADA domain either partially or entirely were tested for activity in vitro, together with an ADA‐adenylation didomain and the ADA domainless adenylation domain. We provide evidence that the ADA domain is required for substrate adenylation: that is, the initial step of the catalytic turnover. Our biochemical data are supported by in silico modeling that identified the ADA domain as a partial peptide synthetase condensation domain. 相似文献
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Ermittlung von Temperaturverteilung, Abkühlungsverlauf, Gefüge, Härte und Eigenspannungen bei mittig erwärmten Stahlplatten aus St 37-3 und StE 70. Einfluß des Umwandlungsverhaltens auf die Eigenspannungen. Deutung der Eigenspannungsentstehung beim Zusammenwirken von Wärme- und Umwandlungsspannungen. 相似文献
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Untersuchung des Schrumpfungs- und Umwandlungsverhaltens von Schweißproben aus austenitischem und hochfestem Grund- und Schweißzusatzwerkstoff. Messung von Eigenspannungen im Schweißnahtbereich. Erklärung der Eigenspannungen aus Temperaturverläufen und Härtemessungen im Schweißnahtbereich sowie aus Weg-Zeit-Aufschreibungen für das freie Ende einseitig eingespannter Schweißproben. Deutung der Umwandlungsvorgänge durch Zeit-Temperatur-Umwandlungsschaubilder. 相似文献
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Alireza Kondori Zhen Jiang Mohammadreza Esmaeilirad Mahmoud Tamadoni Saray Arvin Kakekhani Kamil Kucuk Pablo Navarro Munoz Delgado Sadaf Maghsoudipour John Hayes Christopher S. Johnson Carlo U. Segre Reza Shahbazian-Yassar Andrew M. Rappe Mohammad Asadi 《Advanced materials (Deerfield Beach, Fla.)》2020,32(50):2004028
The main drawbacks of today's state-of-the-art lithium–air (Li–air) batteries are their low energy efficiency and limited cycle life due to the lack of earth-abundant cathode catalysts that can drive both oxygen reduction and evolution reactions (ORR and OER) at high rates at thermodynamic potentials. Here, inexpensive trimolybdenum phosphide (Mo3P) nanoparticles with an exceptional activity—ORR and OER current densities of 7.21 and 6.85 mA cm−2 at 2.0 and 4.2 V versus Li/Li+, respectively—in an oxygen-saturated non-aqueous electrolyte are reported. The Tafel plots indicate remarkably low charge transfer resistance—Tafel slopes of 35 and 38 mV dec−1 for ORR and OER, respectively—resulting in the lowest ORR overpotential of 4.0 mV and OER overpotential of 5.1 mV reported to date. Using this catalyst, a Li–air battery cell with low discharge and charge overpotentials of 80 and 270 mV, respectively, and high energy efficiency of 90.2% in the first cycle is demonstrated. A long cycle life of 1200 is also achieved for this cell. Density functional theory calculations of ORR and OER on Mo3P (110) reveal that an oxide overlayer formed on the surface gives rise to the observed high ORR and OER electrocatalytic activity and small discharge/charge overpotentials. 相似文献
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Dr. Larissa Doll Jens Lackner Dr. Franziska Rönicke Prof. Dr. Gerd Ulrich Nienhaus Prof. Dr. Hans-Achim Wagenknecht 《Chembiochem : a European journal of chemical biology》2021,22(15):2561-2567
For monitoring the intracellular pathway of small interfering RNA (siRNA), both strands were labelled at internal positions by two ATTO dyes as an interstrand Förster resonance energy transfer pair. siRNA double strands show red emission and a short donor lifetime as readout, whereas siRNA antisense single strands show green emission and a long donor lifetime. This readout signals if GFP silencing can be expected (green) or not (red). We attached both dyes to three structurally different alkyne anchors by postsynthetic modifications. There is only a slight preference for the ribofuranoside anchors with the dyes at their 2’-positions. For the first time, the delivery and fate of siRNA in live HeLa cells was tracked by fluorescence lifetime imaging microscopy (FLIM), which revealed a clear relationship between intracellular transport using different transfection methods and knockdown of GFP expression, which demonstrates the potential of our siRNA architectures as a tool for future development of effective siRNA. 相似文献
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Werner Heimann Karl-Heinz Franzen Adolf Rappe und Herbert Ullemeyer 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1976,162(2):109-114
Zusammenfassung Während der Incubation von Soja-Lipoxygenase mit Linolsäure entstehen flüchtige Verbindungen, für deren Genese sich mindestens zwei Möglichkeiten abzeichnen: Die eine Möglichkeit besteht darin, daß aus bereits vorgebildeten Linolsäurehydroperoxiden Spaltprodukte auftreten. Zum andern können — je nach äußeren Bedingungen (Temperatur, O2-Druck, Partnerkonzentration, u.a.) — flüchtige Stoffe verschiedener chemischer Natur aus radikalischen Reaktionszwischenstufen entstehen. Durch Versuche mit Hydroperoxid-abbauenden Enzymen (Peroxidasen) und unter Verwendung radioaktiv markierter Linolsäurehydroperoxide wurden die angedeuteten Bildungswege untersucht. Unsere epxerimentellen Ergebnisse zeigen, daß die Bildung der hier untersuchten flüchtigen Verbindungen aus Reaktionszwischenstufen vor sich geht. Festzuhalten ist jedoch, daß n-Hexanal neben der Bildung aus Reaktionszwischenstufen auch aus dem Zerfall vorher gebildeter Hydroperoxide entsteht. Das schon von uns früher angegebene Rekationsschema [2] konnte nunmehr durch diese Untersuchungen experimentell gesichert werden.
Herrn Prof. Dr. J. Eisenbrand zum 75. Geburtstag gewidmet. 相似文献
Investigations on the development of volatile substances during lipoxygenase-linolic-acid-reaction
Summary During incubation of soja-Lipoxygenase with Linolic acid, volatile compounds are formed the development of which can be seen in two possible ways: from preformed Linolic-acid-hydroperoxides splitproducts arise or volatile substances of different chemical nature are built depending on the reaction conditions like temperature, O2-pressure, partner-concentration etc. By trials with hydroperoxdde-decomposing enzymes (peroxidase) and by means of radioactive labelled Linolic-acid-hydroperoxides the pathways mentioned above were investigated. The results indicate that the volatile compounds are built from by-products; n-hexanal was formed from these by-products as well as from decomposed hydroperoxide. The previously proposed reaction-scheme has this been ascertained by experimental means.
Herrn Prof. Dr. J. Eisenbrand zum 75. Geburtstag gewidmet. 相似文献
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Materials science evolves to a state where the composition and structure of a crystal can be controlled almost at will. Given that a composition meets basic requirements of stoichiometry, steric demands, and charge neutrality, researchers are now able to investigate a wide range of compounds theoretically and, under various experimental conditions, select the constituting fragments of a crystal. One intriguing playground for such materials design is the perovskite structure. While a game of mixing and matching ions has been played successfully for about 150 years within the limits of inorganic compounds, the recent advances in organic–inorganic hybrid perovskite photovoltaics have triggered the inclusion of organic ions. Organic ions can be incorporated on all sites of the perovskite structure, leading to hybrid (double, triple, etc.) perovskites and inverse (hybrid) perovskites. Examples for each of these cases are known, even with all three sites occupied by organic molecules. While this change from monatomic ions to molecular species is accompanied with increased complexity, it shows that concepts from traditional inorganic perovskites are transferable to the novel hybrid materials. The increased compositional space holds promising new possibilities and applications for the universe of perovskite materials. 相似文献
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