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排序方式: 共有893条查询结果,搜索用时 31 毫秒
1.
Ilaria Fraudentali Renato A. Rodrigues-Pousada Riccardo Angelini Sandip A. Ghuge Alessandra Cona 《International journal of molecular sciences》2021,22(10)
Polyamines are ubiquitous, low-molecular-weight aliphatic compounds, present in living organisms and essential for cell growth and differentiation. Copper amine oxidases (CuAOs) oxidize polyamines to aminoaldehydes releasing ammonium and hydrogen peroxide, which participates in the complex network of reactive oxygen species acting as signaling molecules involved in responses to biotic and abiotic stresses. CuAOs have been identified and characterized in different plant species, but the most extensive study on a CuAO gene family has been carried out in Arabidopsis thaliana. Growing attention has been devoted in the last years to the investigation of the CuAO expression pattern during development and in response to an array of stress and stress-related hormones, events in which recent studies have highlighted CuAOs to play a key role by modulation of a multilevel phenotypic plasticity expression. In this review, the attention will be focused on the involvement of different AtCuAOs in the IAA/JA/ABA signal transduction pathways which mediate stress-induced phenotypic plasticity events. 相似文献
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Renato Cataluña Rosângela da Silva Eliana Weber de Menezes Ricardo Boeira Ivanov 《Fuel》2008,87(15-16):3362-3368
Oxygenated fuels increase fuel consumption due to their low enthalpy of combustion; however, their high antiknock index renders them suitable for use in engines with a high compression rate, increasing their thermal yield. This study evaluated the performance of biorenewable oxygenated fuels (ethanol and isoamyl alcohol) and partially renewable fuels (ETBE: ethyl tert-butyl ether, TAEE: tert-amyl ethyl ether and di-TAE: di-tert-amyl ether) with high degree of purity and in mixtures with automotive gasoline, based on tests with Otto cycle engines. Among the oxygenated fuels evaluated here, di-TAE was found to present the best characteristics of performance, both individually and in mixtures with gasoline. 相似文献
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Renato Maia Renato Cerqueira Clarisse Sieckenius de Souza Tomás Guisasola-Gorham 《Empirical Software Engineering》2012,17(3):166-199
Today middleware is much more powerful, more reliable and faster than it used to be. Nevertheless, for the application developer,
the complexity of using middleware platforms has increased accordingly. The volume and variety of application contexts that
current middleware technologies have to support require that developers be able to anticipate the widest possible range of
execution environments, desired and undesired effects of different programming strategies, handling procedures for runtime
errors, and so on. This paper shows how a generic framework designed to evaluate the usability of notations (the Cognitive Dimensions of Notations Framework, or CDN) has been instantiated and used to analyze the cognitive
challenges involved in adapting middleware platforms. This human-centric perspective allowed us to achieve novel results compared
to existing middleware evaluation research, typically centered around system performance metrics. The focus of our study is
on the process of adapting middleware implementations, rather than in the end product of this activity. Our main contributions
are twofold. First, we describe a qualitative CDN-based method to analyze the cognitive effort made by programmers while adapting
middleware implementations. And second, we show how two platforms designed for flexibility have been compared, suggesting
that certain programming language design features might be particularly helpful for developers. 相似文献
6.
Rudolf E. Schmitt Johann Haas und Renato Amadò 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1988,187(2):121-124
Zusammenfassung Zur Bestimmung biogener Amine aus Schlachtgeflügel wird ein einfach durchzuführendes Analysenverfahren beschrieben. Die Amine wurden mit 0,6m-Perchlorsäure extrahiert, nach Dansylierung auf einer RP-18 Säule aufgetrennt und bei 254 nm detektiert. Innerhalb von 7 min konnte eine gute Auftrennung von 8 Aminen erreicht werden. Zur quantitativen Erfassung von Spermin und Spermidin mußte der Extrakt zusätzlich über Amberlite CG 50 gereinigt werden. Die Wiederfindungsraten betrugen 82% bis 96%, die Nachweisgrenzen 0,2 bis 0,5 g pro g Hühnerhaut. Bei Schlachtgeflügel eignen sich Putrescin und Cadaverin gut als Leitsubstanzen für den einsetzenden Verderb, da sie bereits ab Gesamtkoloniezahlen von etwa 105 pro cm2 nachweisbar sind, und ihre Konzentration mit zunehmendem Verderb rasch ansteigen.
Determination of biogenic amines by RP-HPLC for monitoring microbial spoilage of poultry
Summary A simple high-performance liquid chromatographic (HPLC) analysis is described for the determination of biogenic amines in broiler carcasses. The clean-up procedure consists of an extraction with 0.6M-perchloric acid, formation of dansyl derivatives, separation by a RP-18 column and UV detection at 254 nm. Within 7 min eight amines could be separated. The quantitative determination of spermidine and spermine requires an additional ion-exchange clean-up with Amberlite CG 50 after the extraction. This procedure gives recoveries of 82%–96% with detection limits of 0.2–0.5 g/g of broiler skin. Putrescine and cadaverine are good indicators for the onset of spoilage of poultry carcasses, since both amines could be detected at total colony counts of 105 cfu/cm2 and their concentration increases rapidly with advancing decomposition.相似文献
7.
Rafael S. Pinto João P. Serra João C. Barbosa Renato Gonçalves Maria M. Silva Senentxu Lanceros-Méndez Carlos M. Costa 《大分子材料与工程》2021,306(11):2100372
Considering the high levels of materials used in the fields of electronics and energy storage systems, it is increasingly necessary to take into consideration environmental impact. Thus, it is important to develop devices based on environmentally friendlier materials and/or processes, such as additive manufacturing techniques. In this work, poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) are prepared by direct-ink-writing (DIW) by varying solvent evaporation temperature and fill density percentage. Different morphologies for both polymers are obtained, including dense films and porous membranes, as well as different electroactive β-phase content, thermal and mechanical properties. The dielectric constant and piezoelectric d33 coefficient for dense films reaches up to 16 at 1 kHz and 4 pC N−1, respectively for PVDF-HFP with a fill density of 80 and a solvent evaporation temperature of 50 °C. Porous structures are developed for battery separator membranes in lithium-ion batteries, with a highest ionic conductivity value of 3.8 mS cm−1 for the PVDF-HFP sample prepared with a fill density of 100 and a solvent evaporation temperature of 25 °C, the sample showing an excellent cycling performance. It is demonstrated that electroactive films and membranes can be prepared by direct-ink writing suitable for sensors/actuators and energy storage systems. 相似文献
8.
In traditional networks special efforts are put to secure the perimeter with firewalls: particular routers that analyze and filter the traffic to separate zones with different levels of trust. In wireless multi-hop networks the perimeter is a concept extremely hard to identify, thus, it is much more effective to enforce control on the nodes that will route more traffic. But traffic filtering and traffic analysis are costly activities for the limited resources of mesh nodes, so a trade-off must be reached limiting the number of nodes that enforce them. This work shows how, using the OLSR protocol, the centrality of groups of nodes with reference to traffic can be estimated with high accuracy independently of the network topology or size. We also show how this approach greatly limits the impact of an attack to the network using a number of firewalls that is only a fraction of the available nodes. 相似文献
9.
Douglas F. G. Santiago Renato Portugal Nolmar Melo 《Quantum Information Processing》2013,12(5):1871-1884
It is known that nonadditive quantum codes can have higher code dimensions than stabilizer codes for the same length and minimum distance. The class of codeword stabilized codes (CWS) provides tools to obtain new nonadditive quantum codes by reducing the problem to finding nonlinear classical codes. In this work, we establish some results on the kind of non-Pauli operators that can be used as observables in the decoding scheme of CWS codes and propose a procedure to obtain those observables. 相似文献
10.
Romain Carron Enrico Avancini Thomas Feurer Benjamin Bissig Paolo A. Losio Renato Figi 《Science and Technology of Advanced Materials》2018,19(1):396-410
Cu(In,Ga)Se2-based solar cells have reached efficiencies close to 23%. Further knowledge-driven improvements require accurate determination of the material properties. Here, we present refractive indices for all layers in Cu(In,Ga)Se2 solar cells with high efficiency. The optical bandgap of Cu(In,Ga)Se2 does not depend on the Cu content in the explored composition range, while the absorption coefficient value is primarily determined by the Cu content. An expression for the absorption spectrum is proposed, with Ga and Cu compositions as parameters. This set of parameters allows accurate device simulations to understand remaining absorption and carrier collection losses and develop strategies to improve performances. 相似文献