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排序方式: 共有116条查询结果,搜索用时 15 毫秒
31.
Victoria P. A. Johnstone Livia C. Hool 《International journal of molecular sciences》2014,15(10):19203-19225
There is mounting evidence to suggest that protein glutathionylation is a key process contributing to the development of pathology. Glutathionylation occurs as a result of posttranslational modification of a protein and involves the addition of a glutathione moiety at cysteine residues. Such modification can occur on a number of proteins, and exerts a variety of functional consequences. The L-type Ca2+ channel has been identified as a glutathionylation target that participates in the development of cardiac pathology. Ca2+ influx via the L-type Ca2+ channel increases production of mitochondrial reactive oxygen species (ROS) in cardiomyocytes during periods of oxidative stress. This induces a persistent increase in channel open probability, and the resulting constitutive increase in Ca2+ influx amplifies the cross-talk between the mitochondria and the channel. Novel strategies utilising targeted peptide delivery to uncouple mitochondrial ROS and Ca2+ flux via the L-type Ca2+ channel following ischemia-reperfusion have delivered promising results, and have proven capable of restoring appropriate mitochondrial function in myocytes and in vivo. 相似文献
32.
Luigi Sorrentino Livia Cafiero Salvatore Iannace 《Polymer Engineering and Science》2015,55(6):1281-1289
High performance thermoplastic blends based on polyethersulfone (PES) and poly(ethylene 2,6 naphthalate) (PEN) were foamed with supercritical CO2 to develop high‐performance foams with improved heat deflection temperature, extended processing range, and controlled cellular morphology. The cellular morphology resulted to be strongly influenced by the initial morphology of the blend. The presence of small amount of PES as dispersed phase in PEN based blends acted as blowing agent reservoir and allowed to extend the processing temperature range for obtaining low density foams. The presence of PEN droplets in PES based systems extended the foaming temperatures towards lower values and allowed the development of a bimodal micro/nanocellular morphology at a foaming temperature 60°C lower than the PES glass transition temperature. Furthermore, the presence of PEN droplets compensated for the reduced capability of the host matrix to generate a fine and diffuse porosity at low foaming temperatures. POLYM. ENG. SCI., 55:1281–1289, 2015. © 2015 Society of Plastics Engineers 相似文献
33.
Phoa Frederick Kin Hing Lai Hsin-Yi Chang Livia Lin-Hsuan Honda Keisuke 《Scientometrics》2020,125(2):851-863
Scientometrics - It is common sense that some subjects have strong relationships while others are perhaps almost mutually independent, but a quantitative and systematic approach to describe such... 相似文献
34.
Livia Simon-Sarkadi Wilhelm H. Holzapfel 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1994,198(3):230-233
An automated ion-exchange Chromatographic method is described for determination of biogenic amines in leafy vegetables using a cation-exchange resin column in potassium form and a three-buffer system. The following amines were separated and quantified for Chinese cabbage, endive, iceberg lettuce and radiocchio: putrescine, histamine, cadaverine, spermidine, agmatine, spermine, tyramine. Amines from vegetable samples were extracted with 10% trichloroacetic acid. The total concentration of these amines ranged from 14 to 20 g/g fresh weight. Spermidine was the major polyamine detected, present at concentrations of 7–15 g/g fresh weight.
Bestimmung biogener Amine in Blattgemüse mit dem Aminosäureanalysator
Zusammenfassung Es wird eine Methode zur Bestimmung biogener Amine in Blattgemüse mittels automatisierter Ionenaustausch-Chromatographie beschrieben. Die Trennung erfolgte auf einer K+-Kationenaustauschersäule mit Hilfe eines Drei-Puffer-Systems. In Chinakohl, Endivie, Eisbergsalat und Radicchio sind folgende Amine bestimmt worden: Putrescin, Histamin, Cadaverin, Spermidin, Agmatin, Spermin und Tyramin. Die Extraktion erfolgte mit 10% Trichloressigsäure. Die Gesamtkonzentration biogener Amine betrug 14–20 g/ g Frischsubstanz. Von den nachgewiesenen Polyaminen war Spermidin mit einer Konzentration von 7–15 g Frischsubstanz am stärksten vertreten.相似文献
35.
The authors investigated the differences between 8-year-olds (n = 80) and adults (n = 80) in recognition of felt versus faked enjoyment smiles by using a newly developed picture set that is based on the Facial Action Coding System. The authors tested the effect of different facial action units (AUs) on judgments of smile authenticity. Multiple regression showed that children base their judgment on AU intensity of both mouth and eyes, with relatively little distinction between the Duchenne marker (AU6 or "cheek raiser") and a different voluntary muscle that has a similar effect on eye aperture (AU7 or "lid tightener"). Adults discriminate well between AU6 and AU7 and seem to use eye-mouth discrepancy as a major cue of authenticity. Bared-teeth smiles (involving AU25) are particularly salient to both groups. The authors propose and discuss an initial developmental model of the smile recognition process. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
36.
The perceptions of authoritarians (highs) by other authoritarians and nonauthoritarians (lows) by other nonauthoritarians are investigated by placing 12 pairs of highs and 12 pairs of lows in a social situation and instructing them to discuss the neutral topics of radio, television, and the movies. Each S had previously responded to the F scale along with some buffer MMPI items. After the discussion was completed, each S was again given the questionnaire, but was instructed to respond to it as he felt his partner would answer it. The combined data of this, and a previous study show that highs tend to estimate peers as having high attitudes, whether these peers are high or low. The estimates by lows of peers are less uniform than those of highs. The social perceptions of highs appear to be influenced by a "same-stereotype" while those of lows by an "other-stereotype." (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
37.
Silvia Bradamante Livia Barenghi Silvia Versari Alessandro Villa 《Microgravity science and technology》2006,18(3-4):250-253
Cardiovascular system functions are impaired in altered gravity conditions. In particular endothelial cells play a major role being responsible for the integrity of the vascular wall. Due to obvious difficulties in performing continuous and exhaustive experiments in space, most of the available data have been obtained so far using various simulators of hypergravity and microgravity (µg) conditions. The consistency of the data resides on the reliability of the simulator, being a critical point in the development of the research. We exposed the cell cultures to 1) hypergravity (launch condition) using MidiCAR at Dutch Experiment Support Center (DESC, NL); 2) simulated µg using the Rotating Wall Vessel (RWV) and the Random Positioning Machine (RPM). We used two different cellular models: human umbilical vein endothelial cells (HUVEC) and human leukocytes (U937). Only few experiments on cells using RPM have been reported. To assess the RPM best operative parameters we considered data from experiments in space on U937 as reference standard. Differently, cultures in modelled µg using RWV have been extensively reported. Our data on HUVEC indicate that the two µg simulators provide analogous results in terms of proliferation and cytoskeletal organization. Finally, to investigate the effects of spaceflight on different human cells, we developed a spaceflight-like protocol consisting of an initial hypergravity phase (launch), followed by a µg simulation (orbital flight). Using this protocol, results show that hypergravity limits in our models the effects on proliferation induced by modelled µg. 相似文献
38.
Mathieu Lemay Livia Aumand WilliamW. Ogilvie 《Advanced Synthesis \u0026amp; Catalysis》2007,349(3):441-447
Conformational control was utilized to design a hydrazide organocatalyst for asymmetric Diels–Alder reactions, thus introducing a new aspect to organocatalysis. Diastereoselectivities and enantioselectivities of up to 96 % were achieved by the application of the rigidified catalyst. The first crystal structure of a key iminium intermediate in an organocatalyzed process is also provided. 相似文献
39.
Bice Cavallo Livia D’Apuzzo 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(2):353-366
In this paper, at first, we provide some results on the group of vectors with components in a divisible Abelian linearly ordered
group, the related subgroup of
\odot\odot-normal vectors, the relation of
\odot\odot-proportionality and the corresponding quotient group. Then, we apply the achieved results to the groups of reciprocal and
consistent matrices over divisible Abelian linearly ordered groups; this allows us to deal with the problem of deriving a
weighting ranking for the alternatives from a pairwise comparison matrix. The proposed weighting vector has several advantages;
it satisfies, for instance, the independence of scale-inversion condition. 相似文献
40.
We all make use of oxide ultrathin films, even if we are unaware of doing so. They are essential components of many common devices, such as mobile phones and laptops. The films in these ubiquitous electronics are composed of silicon dioxide, an unsurpassed material in the design of transistors. But oxide films at the nanoscale (typically just 10 nm or less in thickness) are integral to many other applications. In some cases, they form under normal reactive conditions and confer new properties to a material: one example is the corrosion protection of stainless steel, which is the result of a passive film. A new generation of devices for energy production and communications technology, such as ferroelectric ultrathin film capacitors, tunneling magnetoresistance sensors, solar energy materials, solid oxide fuel cells, and many others, are being specifically designed to exploit the unusual properties afforded by reduced oxide thickness. Oxide ultrathin films also have tremendous potential in chemistry, representing a rich new source of catalytic materials. About 20 years ago, researchers began to prepare model systems of truly heterogeneous catalysts based on thin oxide layers grown on single crystals of metal. Only recently, however, was it realized that these systems may behave quite differently from their corresponding bulk oxides. One of the phenomena uncovered is the occurrence of a spontaneous charge transfer from the metal support to an adsorbed species through the thin insulating layer (or vice versa). The importance of this property is clear: conceptually, the activation and bond breaking of adsorbed molecules begin with precisely the same process, electron transfer into an antibonding orbital. But electron transfer can also be harnessed to make a supported metal particle more chemically active, increase its adhesion energy, or change its shape. Most importantly, the basic principles underlying electron transfer and other phenomena (such as structural flexibility, electronic modifications, and nanoporosity) are now largely understood, thus paving the way for the rational design of new catalytic systems based on oxide ultrathin films. Many of the mechanisms involved (electron tunneling, work function changes, defects engineering, and so forth) are typical of semiconductor physics and allow a direct link between the two fields. A related conceptual framework, the "electronic theory of catalysis", was proposed a long time ago but has been largely neglected by the catalytic community. A renewed appreciation of this catalytic framework, together with spectacular advances in modeling and electronic structure methods, now makes it possible to combine theory with advanced experimental setups and meet the challenge of designing new materials with tailored properties. In this Account, we discuss some of the recent advances with nanoscale oxide films, highlighting contributions from our laboratory. Once mastered, ultrathin oxide films on metals will provide vast and unforeseen opportunities in heterogeneous catalysis as well as in other fields of science and technology. 相似文献