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21.
Truman JP Al Gadban MM Smith KJ Hammad SM 《Cellular and molecular life sciences : CMLS》2011,68(20):3293-3305
Macrophages play a central role in innate immune responses, in disposal of cholesterol, and in tissue homeostasis and remodeling.
To perform these vital functions macrophages display high endosomal/lysosomal activities. Recent studies have highlighted
that acid sphingomyelinase (ASMase), which generates ceramide from sphingomyelin, is involved in modulation of membrane structures
and signal transduction in addition to its metabolic role in the lysosome. In this review, we bring together studies on ASMase,
its different forms and locations that are necessary for the macrophage to accomplish its diverse functions. We also address
the importance of ASMase to several disease processes that are mediated by activated macrophages. 相似文献
22.
Giri G Verploegen E Mannsfeld SC Atahan-Evrenk S Kim do H Lee SY Becerril HA Aspuru-Guzik A Toney MF Bao Z 《Nature》2011,480(7378):504-508
Circuits based on organic semiconductors are being actively explored for flexible, transparent and low-cost electronic applications. But to realize such applications, the charge carrier mobilities of solution-processed organic semiconductors must be improved. For inorganic semiconductors, a general method of increasing charge carrier mobility is to introduce strain within the crystal lattice. Here we describe a solution-processing technique for organic semiconductors in which lattice strain is used to increase charge carrier mobilities by introducing greater electron orbital overlap between the component molecules. For organic semiconductors, the spacing between cofacially stacked, conjugated backbones (the π-π stacking distance) greatly influences electron orbital overlap and therefore mobility. Using our method to incrementally introduce lattice strain, we alter the π-π stacking distance of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) from 3.33?? to 3.08??. We believe that 3.08?? is the shortest π-π stacking distance that has been achieved in an organic semiconductor crystal lattice (although a π-π distance of 3.04?? has been achieved through intramolecular bonding). The positive charge carrier (hole) mobility in TIPS-pentacene transistors increased from 0.8?cm(2)?V(-1)?s(-1) for unstrained films to a high mobility of 4.6?cm(2)?V(-1)?s(-1) for a strained film. Using solution processing to modify molecular packing through lattice strain should aid the development of high-performance, low-cost organic semiconducting devices. 相似文献
23.
24.
Zeinab?Karake?ShalhoubEmail author Jameela?Al?Qasimi 《Systemic Practice and Action Research》2005,18(5):457-473
The purpose of the paper is to analyze the Sharjah City for Humanitarian Services (SCHS), a not-for-profit organization serving
people with disabilities in the United Arab Emirates (UAE), from a soft systems methodology (SSM) perspective.
Deputy Chairperson of the Family Supreme Council and Director-General of Sharjah City for Humanitarian Services (SCHS).
Examples of Journals dedicated to the nonprofit sector are Nonprofit& Voluntary Sector Quarterly, Voluntos and Nonprofit Management & Leadership. 相似文献
25.
The origins of the building blocks of the Solar System can be studied using the isotopic composition of early planetary and meteoritic material. Oxygen isotopes in planetary materials show variations at the per cent level that are not related to the mass of the isotopes; rather, they result from the mixture of components having different nucleosynthetic or chemical origins. Isotopic variations reaching orders of magnitude in minute meteoritic grains are usually attributed to stellar nucleosynthesis before the birth of the Solar System, whereby different grains were contributed by different stars. Here we report the discovery of abundant silica-rich grains embedded in meteoritic organic matter, having the most extreme 18O/16O and 17O/16O ratios observed (both approximately 10(-1)) together with a solar silicon isotopic composition. Both O and Si isotopes indicate a single nucleosynthetic process. These compositions can be accounted for by one of two processes: a single exotic evolved star seeding the young Solar System, or irradiation of the circumsolar gas by high energy particles accelerated during an active phase of the young Sun. We favour the latter interpretation, because the observed compositions are usually not expected from nucleosynthetic processes in evolved stars, whereas they are predicted by the selective trapping of irradiation products. 相似文献
26.
The zoeal stages of Hiplyra variegata are described and illustrated for the first time. Zoea I was obtained from an ovigerous female, and the zoea II and zoea III stages were captured in the plankton (their identity was confirmed by rearing some of them from earlier stages). Comparisons are made with the only other species of the genus of which larvae are known, i.e. H. platycheir. The presence of a lateral spine on the carapace of zoea I is one of the most important characters that can be used for easy recognition of H. variegata. It is important to note that the third zoea of H. variegata has four small spines at each posterolateral margin of the carapace, in contrast to three spines in other species. 相似文献
27.
Mostafa R. Sharaf Amr A. Mohamed Hathal M. Al Dhafer Abdulrahman S. Aldawood 《Journal of Natural History》2020,54(5-6):351-365
ABSTRACT A new species of the myrmicine ant genus Nesomyrmex Wheeler, 1910, N. micheleae Sharaf sp. nov., is described and illustrated from Oman based on the worker caste. The new species is a member of the N. angulatus species group and can be diagnosed by the golden yellow gaster that contrasts with the dark brown body; the irregular longitudinal rugulose sculpture on the cephalic surface; and the finely punctate mesonotum and propodeal dorsum. A synoptic species list, an updated key and a distribution map to the Arabian Nesomyrmex species are presented. Continued ant species discoveries are central to large-scale diversity patterns, conservation biology and macroecology. http://www.zoobank.org/urn:lsid:zoobank.org:pub:FBCEACA7-E543-4B10-AB9D-D63319DCB31F http://www.zoobank.org/urn:lsid:zoobank.org:act:1D2EC498-3B2E-43CD-A3C0-1C6C237471E2 相似文献
28.
Multi-component Bose-Einstein condensates provide opportunities to explore experimentally the wealth of physics associated with the spin degrees of freedom. The ground-state properties and line-like vortex excitations of these quantum systems have been studied theoretically. In principle, nontrivial spin textures consisting of point-like topological excitations, or skyrmions, could exist in a multi-component Bose-Einstein condensate, owing to the superfluid nature of the gas. Although skyrmion excitations are already known in the context of nuclear physics and the quantum-Hall effect, creating these excitations in an atomic condensate would offer an opportunity to study their physical behaviour in much greater detail, while also enabling an ab initio comparison between theory and experiment. Here we investigate theoretically the stability of skyrmions in a fictitious spin-1/2 condensate of 87Rb atoms. We find that skyrmions can exist in such a gas only as a metastable state, but with a lifetime comparable to (or even longer than) the typical lifetime of the condensate itself. 相似文献
29.
M. Ali L. H. J. Hayat J. Al Saleh C. J. Gubler 《Cellular and molecular life sciences : CMLS》1989,45(1):112-114
Summary Drinking of both green and black tea as the only liquid ingested resulted in significant decreases in the activity of transketolase in whole blood of rats both before and after the in vitro addition, of thiamin diphosphate. Liver transketolase activity was decreased only by green tea. Mucosal transketolase activity was not affected by either type of tea. The activity of lactate dehydrogenase (LDH) was not affected by either type of tea, while whole blood LDH was decreased by both green and black tea. Neither tea had any affect on mucosal alkaline phosphatase, but thiamin diphosphatase activity was decreased by both teas. An increase in liver total thiamin resulted from the drinking of both types of tea. 相似文献
30.
Impaired response to interferon-alpha/beta and lethal viral disease in human STAT1 deficiency 总被引:22,自引:0,他引:22