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21.
Pauline V. Marck Marco T. Pessoa Yunhui Xu Laura C. Kutz Dominic M. Collins Yanling Yan Cierra King Xiaoliang Wang Qiming Duan Liquan Cai Jeffrey X. Xie Jerry B. Lingrel Zijian Xie Jiang Tian Sandrine V. Pierre 《International journal of molecular sciences》2021,22(7)
The Na/K-ATPase is the specific receptor for cardiotonic steroids (CTS) such as ouabain and digoxin. At pharmacological concentrations used in the treatment of cardiac conditions, CTS inhibit the ion-pumping function of Na/K-ATPase. At much lower concentrations, in the range of those reported for endogenous CTS in the blood, they stimulate hypertrophic growth of cultured cardiac myocytes through initiation of a Na/K-ATPase-mediated and reactive oxygen species (ROS)-dependent signaling. To examine a possible effect of endogenous concentrations of CTS on cardiac structure and function in vivo, we compared mice expressing the naturally resistant Na/K-ATPase α1 and age-matched mice genetically engineered to express a mutated Na/K-ATPase α1 with high affinity for CTS. In this model, total cardiac Na/K-ATPase activity, α1, α2, and β1 protein content remained unchanged, and the cardiac Na/K-ATPase dose–response curve to ouabain shifted to the left as expected. In males aged 3–6 months, increased α1 sensitivity to CTS resulted in a significant increase in cardiac carbonylated protein content, suggesting that ROS production was elevated. A moderate but significant increase of about 15% of the heart-weight-to-tibia-length ratio accompanied by an increase in the myocyte cross-sectional area was detected. Echocardiographic analyses did not reveal any change in cardiac function, and there was no fibrosis or re-expression of the fetal gene program. RNA sequencing analysis indicated that pathways related to energy metabolism were upregulated, while those related to extracellular matrix organization were downregulated. Consistent with a functional role of the latter, an angiotensin-II challenge that triggered fibrosis in the α1r/rα2s/s mouse failed to do so in the α1s/sα2s/s. Taken together, these results are indicative of a link between circulating CTS, Na/K-ATPase α1, ROS, and physiological cardiac hypertrophy in mice under baseline laboratory conditions. 相似文献
22.
An exact solution inside, outside, and within two arbitrary concentric spherical shells is presented for an impinging monochromatic linearly polarized electromagnetic wave. Specifically, the solution was found for a double-shell spherical acrylic plastic enclosure irradiated with 2450-MHz microwaves. The enclosure is used as an environmentally controlled exposure chamber for experimental animals during microwave irradiation. The analysis shows that an air foamed material, such as styrofoam, would be a better material than either Plexiglas or Teflon, provided it is sufficiently durable. 相似文献
23.
Janaina Braga do?CarmoEmail author Christopher?Neill Diana?C.?Garcia-Montiel Marisa?de Cássia Piccolo Carlos?C.?Cerri Paul?A.?Steudler Cristiano Alberto?de Andrade Caio?C.?Passianoto Brigitte?J.?Feigl Jerry?M.?Melillo 《Nutrient Cycling in Agroecosystems》2005,71(3):213-225
The clearing of tropical rain forest in the Amazon basin has created large areas of cattle pasture that are now declining in productivity. Practices adopted by ranchers to restore productivity to degraded pastures have the potential to alter soil N availability and gaseous N losses from soils. We examined how soil inorganic N pools, net N mineralization and net nitrification rates, nitrification potential and NO and N2O emissions from soils of a degraded pasture responded to the following restoration treatments: (1) soil tillage followed by replanting of grass and fertilization, (2) no-till application of non-selective herbicide, planting of rice, harvest followed by no-till replanting of grass and fertilization, and (3) the same no-till sequence with soybeans instead of rice. Tillage increased soil NH4+ and NO3? pools but NH4+ and NO3? pools remained relatively constant in the control and no-till treatments. Cumulative rates of net N mineralization and net nitrification during the first 6 months after treatment varied widely but were hightest in the tilled treatment. Emissions of NO and N2O fluxes increased with tillage and with N fertilization. There were no clear relationships among rates of N fertilizer application, net N mineralization, net nitrification, NO, N2O and total N oxide emissions. Our results indicate that pasture restoration sequences involving tilling and fertilizing will increase emissions of N oxides, but the magnitude of the increase is likely to differ based on timing of fertilizer application relative to the presence of plants and the magnitude of plant N demand. Emissions of N oxides appear to be decreased by the use of restoration sequences that minimize reductions in pasture grass cover. 相似文献
24.
Wei-Heng Shih David Kisailus Wan Y. Shih Yung-Haw Hu Jerry Hughes 《Journal of the American Ceramic Society》1996,79(5):1155-1162
In an attempt to improve the colloidal processing of Si3 N4 ceramics, we studied the rheology and consolidation of colloidal suspensions of Si3 N4 particles (average particle size 0.7 μm) with small Al2 O3 particles (average particle size 20 nm). It was found that at pH >7, the viscosity of the mixtures increased and then decreased with an increasing concentration of Al2 O3 . λpotential measurements, optical micrographs, and visible light absorptance measurement suggest that such viscosity behavior is due to clustering of Si3 N4 particles bridged by the small Al2 O3 particles. This is also supported by the Derjaquin-Landau-Verwey-Overbeek (DLVO) potential calculations that show the barrier height in the DLVO potential between Al2 O3 and Si3 N4 is small. The small barrier height under current experimental conditions stems from the small size of the Al2 O3 particles. The small barrier height allows the thermal motion of the two kinds of particles to overcome the barrier and attach to each other. The adsorption of small Al2 O3 particles on Si3 N4 can occur even when both Al2 O3 and Si3 N4 carry the same sign of charges. The adsorption of Al2 O3 on Si3 N4 also increases the density of consolidated compacts. 相似文献
25.
Jim D. Earls Jerry E. White Marvin L. Dettloff Marty J. Null 《Journal of Coatings Technology and Research》2004,1(3):243-245
Epoxidized 10-undecenoic acid triglyceride, an experimental seed oil derivative that has a terminal epoxy group on each of
the three acyl glyceride segments, has been found to have good reactivity with amine curatives and allows room temperature
cures to be obtained. Coatings based on epoxidized 10-undercenoic acid triglyceride have also shown excellent UV stability.
As an example, coatings samples placed in a QUVA chamber exhibit no loss in gloss after 3000 hr of a cycled exposure to high
intensity UV lamps and moisture at temperatures of 50–60°C. In comparison, coatings based on standard liquid epoxy resins
(LERs) and commercially available hydrogenated LERs lose gloss due to chalking/decomposition within 200–800 hr.
Presented at the 81 st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia,
PA. 相似文献
26.
Jerry Kang 《Datenschutz und Datensicherheit - DuD》2011,35(9):624-628
We often see the government or the corporation as the greatest threat to information privacy. But due to a nascent data practice
called “self-surveillance,” the greatest threat may actually come from ourselves. Using various existing and emerging technologies,
such as GPS-enabled smartphones, we are beginning voluntarily to measure ourselves in granular detail - how long we sleep,
where we go, what we breathe, what we eat, how we spend our time. And we are storing these data casually in the “cloud,” and
giving third-parties broad access. This practice of self-surveillance will decrease information privacy in troubling ways.
To counter this trend, we recommend the creation of the Personal Data Guardian, a new professional who manages Personal Data
Vaults, which are repositories for self-surveillance data. 相似文献
27.
28.
Jerry L. Trahan Mingxian Jin Wittaya Chantamas Johnnie W. Baker 《Journal of Parallel and Distributed Computing》2010
The MASC (Multiple ASsociative Computing) model is a multi-SIMD model that uses control parallelism to coordinate the interaction of data parallel threads and supports associative SIMD computing on each of its threads. There have been a wide range of algorithms developed for this model. Research on using this model in real-time system applications and building a scalable MASC architecture is currently quite active. In this paper, we present simulations between MASC and reconfigurable bus-based models, e.g., various versions of the Reconfigurable Multiple Bus Machine (RMBM). Constant time simulations of the basic RMBM by MASC and vice versa are obtained. Simulations of the segmenting RMBM, fusing RMBM, and extended RMBM by MASC in non-constant time are also discussed. By taking advantage of previously established relationships between RMBM and two other popular parallel computational models, namely, the Reconfigurable Mesh (RM) and the Parallel Random Access Machine (PRAM), we extend our simulation results to further categorize the power of the MASC model in relation to RM and PRAM. 相似文献
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