排序方式: 共有21条查询结果,搜索用时 15 毫秒
1.
Li YF Polgar O Okada M Esser L Bates SE Xia D 《Journal of molecular graphics & modelling》2007,25(6):837-851
The ATP-binding cassette protein ABCG2 is a member of a broad family of ABC transporters with potential clinical importance as a mediator of multidrug resistance. We carried out a homology and knowledge-based, and mutationally improved molecular modeling study to establish a much needed structural framework for the protein, which could serve as guidance for further genetic, biochemical, and structural analyses. Based on homology with known structures of both full-length and nucleotide-binding domains (NBD) of ABC transporters and structural knowledge of integral membrane proteins, an initial model of ABCG2 was established. Subsequent refinement to conform to the lipophilic index distributions in the transmembrane domain (TMD) and to the results of site-directed mutagenesis experiments led to an improved model. The complete ABCG2 model consists of two identical subunits facing each other in a closed conformation. The dimeric interface in the nucleotide-binding domain (NBD) involves a characteristic nucleotide sandwich and the interface in the TMD consists of the TM helices 1–3 of one subunit and the helices 5 and 6 of the other. The interface between the NBD and the TMD is bridged by the conserved structural motif between TM2 and TM3, the intracellular domain 1 (ICD1), and the terminal β-strand (S6) of the central β-sheet in the NBD. The apparent flexibility of the ICD1 may play a role in transmitting conformational changes from the NBD to the TMD or from the TMD to the NBD. 相似文献
2.
Dora Szabo Zsolt Sarszegi Beata Polgar Eva Saghy Adam Nemeth Dora Reglodi Andras Makkos Aniko Gorbe Zsuzsanna Helyes Peter Ferdinandy Robert Herczeg Attila Gyenesei Attila Cziraki Andrea Tamas 《International journal of molecular sciences》2021,22(6)
Acute myocardial infarction (MI) is one of the most common causes of death worldwide. Pituitary adenylate cyclase activating polypeptide (PACAP) is a cardioprotective neuropeptide expressing its receptors in the cardiovascular system. The aim of our study was to examine tissue PACAP-38 in a translational porcine MI model and plasma PACAP-38 levels in patients with ST-segment elevation myocardial infarction (STEMI). Significantly lower PACAP-38 levels were detected in the non-ischemic region of the left ventricle (LV) in MI heart compared to the ischemic region of MI-LV and also to the Sham-operated LV in porcine MI model. In STEMI patients, plasma PACAP-38 level was significantly higher before percutaneous coronary intervention (PCI) compared to controls, and decreased after PCI. Significant negative correlation was found between plasma PACAP-38 and troponin levels. Furthermore, a significant effect was revealed between plasma PACAP-38, hypertension and HbA1c levels. This was the first study showing significant changes in cardiac tissue PACAP levels in a porcine MI model and plasma PACAP levels in STEMI patients. These results suggest that PACAP, due to its cardioprotective effects, may play a regulatory role in MI and could be a potential biomarker or drug target in MI. 相似文献
3.
A. A. Kaplyanskiĭ S. Kapphan A. B. Kutsenko K. Polgar A. P. Skvortsov 《Technical Physics Letters》2007,33(4):337-339
The optical spectra of europium-doped stoichiometric lithium niobate (LiNbO3:Eu3+) crystals have been studied using combined excitation-luminescence spectroscopy in the range of 5D0 → 7F1, 7F0 optical transitions. Analysis of the results shows that Eu3+ ions can occupy 14 energetically nonequivalent positions in the LiNbO3 crystal lattice. This multiplicity of impurity centers is related to possible variants of the incorporation of Eu3+ ions into the LiNbO3 crystal lattice and the compensation of excess charge. Energy positions of the 5D0 level and the lowest sublevel of the 7F1 Stark multiplet are determined for Eu3+ centers of all 14 types. 相似文献
4.
Patrizio Raffa Adamantia Kassi Julian Gosschalk Nicola Migliore Lorenzo Massimo Polgar Francesco Picchioni 《大分子材料与工程》2021,306(4):2000755
A series of copolymers of styrene and furfuryl methacrylate characterized by various molecular structures (linear and star, block and random) is synthesized via atom transfer radical polymerization, and cross-linked with a bismaleimide by means of thermally reversible Diels–Alder (DA) reaction, to obtain self-healing materials. The prepared materials are studied in terms of gelation, swelling, thermal, and dynamic-mechanical analysis, with the aim of correlating relevant properties to their chemical structure. It is found that the furan/styrene ratio, as well as the molecular architecture, have a major influence on the properties. It is also found that the reversibility of the DA reaction is not complete in the solid state for materials with high cross-linking density. This study provides some important tools for the design of materials characterized by thermally reversible behavior, which find usually application as self-healing thermosets, coatings, or adhesives. 相似文献
5.
Wireless Personal Communications - Wireless mesh networks represent a key architecture on which several communication systems are relaying. Implementations of these networks which apply... 相似文献
6.
L. M. Polgar N. Migliore F. Picchioni M. Van Duin 《Polymer-Plastics Technology and Engineering》2020,59(12):1379-1385
ABSTRACTTwo important aspects that should be considered when designing new, sustainable rubber products are the bio-based character of the rubber compound ingredients and the recyclability of the vulcanized rubber product. In this work, both are addressed by compounding a thermoreversible cross-linked EPM rubber with pyrolysis carbon black and squalane as sustainable filler and plasticizer, respectively. The resulting rubber product is fully reprocessable in the melt and it displays material properties comparable to those of compounds with conventional additives with high retention of the material properties upon reprocessing. 相似文献
7.
Location of double bonds in long chain esters by methoxymercuration-demercuration followed by mass spectroscopy 总被引:2,自引:0,他引:2
Methyl esters of simple mono-, di-, and triunsaturated long chain fatty acids quantitatively react with mercuric acetate in
methanol to produce methoxyacetoxymercuri derivatives. Demercuration of these derivatives with sodium borohydride yields methoxylated
fatty acid esters, readily isolable by thin layer chromatography. Mass spectra of the methoxylated esters are characterized
by intense peaks due to cleavage adjacent to methoxy-functions which allow the position of the original double bond in the
chain to be ascertained. The methoxylated derivatives are conveniently analyzed by gas liquid chrovmatography and also by
combined gas chromatographymass spectrometry. In comparison with other methods for double bond location, the procedure described
in simple, reliable, and rapid. 相似文献
8.
A new procedure for determining the position of ethylenic linkages in lipids involves oxidation of the corresponding epoxides
with ethereal periodic acid. The oxidation products are identified by standard techniques such as nuclear magnetic resonance
spectroscopy, mass spectrometry and gas liquid chromatography. 相似文献
9.
Safe driving in older adulthood depends not only on health and driving ability, but also on the driving environment itself, including the type of vehicle. However, little is known about how safety figures into the older driver's vehicle selection criteria and how it ranks among other criteria, such as price and comfort. For this purpose, six focus groups of older male and female drivers (n = 33) aged 70–87 were conducted in two Canadian cities to explore vehicle purchasing decisions and the contribution of safety in this decision. Themes emerged from the data in these categories: vehicle features that keep them feeling safe, advanced vehicular technologies, factors that influence their car buying decisions, and resources that inform this decision. Results indicate older drivers have gaps with respect to their knowledge of safety features and do not prioritize safety at the time of vehicle purchase. To maximize the awareness and uptake of safety innovations, older consumers would benefit from a vehicle design rating system that highlights safety as well as other features to help ensure that the vehicle purchased fits their lifestyle and needs. 相似文献
10.