排序方式: 共有33条查询结果,搜索用时 15 毫秒
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João Serra Sara Sequeira Ismael Domingos Ana Paracana Ermelinda Maçôas Luís V. Melo Bernardo J. Pires Susana Cardoso Diana C. Leitao Helena Alves 《Advanced functional materials》2021,31(47):2105638
Light detection technologies are of interest due to their applications in energy conversion and optical communications. Single-crystal organic semiconductors, such as rubrene, present high detectivities and charge carrier mobility, making them attractive for light-sensing applications. Growth of high crystallinity organic crystals is achieved using vapor processes, forming crystals of arbitrary shapes and orientations and requiring posterior patterning processes. However, patterning the organic semiconductors using industry-standard microfabrication techniques is not straightforward, as these often cause irreversible damage to the crystals. Here the fabrication of patterned micrometric rubrene photosensors is demonstrated through a combination of photolithography and Reactive Ion Etching steps. Protective layers during microfabrication minimize degradation of optoelectronic properties of the organic single crystals during fabrication. Crystals undergoing the patterning process presented a survival rate of 39%. Photoresponse values of up to 41 mA W−1 are obtained under illumination at 500 nm. This opens a route for the industrial-scale fabrication process of high-performance optoelectronic devices based on organic crystals semiconductors. 相似文献
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Several reports have indicated that platelet-activating factor (PAF) may play a role in the physiopathology of nervous tissue.
We previously have demonstrated the presence, in the microsomal fractions of rat brain, of a phosphocholinetransferase which
is able to synthesize PAF by thede novo pathway. The presence of dithiothreitol in the medium increases the rate of PAF biosynthesis, whereas it inhibits the synthesis
of long-chain alkylacyl- and diacyl-glycerophosphocholines (GPC), including dioctanoyl-GPC. This and other properties, such
as pH dependence and thermal stability, indicate that rat brain may have two distinct enzymes for the synthesis of PAF and
other choline phospholipids. The affinity of these enzymes for CDPcholine is similar to that reported for other tissues, the
Km being 42 μm and 55 μm with alkylacetylglycerol and dioctanoylglycerol as lipid substrates, respectively. The Vmax values were 3.0 and 2.2 nmol/mg prot/min for PAF and dioctanoyl-GPC, respectively. In addition, it was shown that the microsomal
fraction of rat brain contains an acetyltransferase which can convert lysoPAF to PAF. Since it has been reported previously
that brain tissue possesses phospholipase A2 activity that can hydrolyze alkylacyl-GPC to lysoPAF, we conclude that brain tissue has all enzymic activities for the synthesis
of PAF by the “remodeling pathway”. The role of the two routes of PAF biosynthesis in nervous tissue remains to be established.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
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Alexandre Gonçalves Ermelinda Silva Cátia Brito Sandra Martins Luís Pinto Lia-Tânia Dinis Ana Luzio Carlos Martins-Gomes Anabela Fernandes-Silva Carlos Ribeiro M. Ângelo Rodrigues José Moutinho-Pereira Fernando M. Nunes Carlos M. Correia 《Journal of the science of food and agriculture》2020,100(2):682-694
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Oriano Francescangeli Vesna Stanic Sofia I. Torgova Alfredo Strigazzi Nicola Scaramuzza Claudio Ferrero Igor P. Dolbnya Thomas M. Weiss Roberto Berardi Luca Muccioli Silvia Orlandi Claudio Zannoni 《Advanced functional materials》2009,19(16):2592-2600
The still undiscovered fluid ferroelectric nematic phase is expected to exhibit a much faster and easier response to an external electric field compared to conventional ferroelectric smectic liquid crystals; therefore, the discovery of such a phase could open new avenues in electro‐optic device technology. Here, experimental evidence of a ferroelectric response to a switching electric field in a low molar mass nematic liquid crystal is reported and connected with field‐induced biaxiality. The fluid is made of bent‐core polar molecules and is nematic over a range of 120 °C. Combining repolarization current measurements, electro‐optical characterizations, X‐ray diffraction and computer simulations, ferroelectric switching is demonstrated and it is concluded that the response is due to field‐induced reorganization of polar cybotactic groups within the nematic phase. This work represents significant progress toward the realization of ferroelectric fluids that can be aligned at command with a simple electric field. 相似文献
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The transfer of radioactivity from cytidine-5′-diphosphate ethanolamine into 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine of neuronal and glial cells from adult rabbit brain cortex has been investigated in vitro.
The synthesis of 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine in both cell populations was stimulated 23–25-fold by the addition of 6 mM alkylacylglycerol.
The neuronal cell-enriched fraction was found to possess/unit protein a 1.7–1.8-fold ethanolaminephosphotransferase activity
(EC 2.7.8.1), as compared to the glial fraction, when saturating concentrations (6 mM) of alkylacylglycerols were added in
the incubation system. The neuronal/glial ratio was 2.6–2.8 in the absence of lipid acceptor or with low concentrations of
alkylacylglycerol. Under most favorable conditions, 6.4 and 3.3. nmoles 1-alkyl-2-acyl-sn-glycerophosphorylethanol-amine/mg protein/30 min was obtained for neurons and glia, respectively. Various kinetic properties
of the 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine synthesizing phosphotransferase activity were found to be similar both in neurons and glia. 相似文献