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81.
A liquid-vapor interface in thermal equilibrium was considered, where the pressure tensor depends upon the density (z) and the position z. The surface tension coefficient results are parametrized with the bulk compressibility, liquid-vapor density difference, and interfacial width along the saturation curve. Previous results at the triple and critical points reported by other investigators are verified. Also included is a plot of the computed results using the parametric equation and experimental data for different substances.  相似文献   
82.
We have investigated the temperature dependence of the electrical transport and the thermogravimetric properties, from -200°C to +1000, of the Bi-Sr-Ca-Cu-O high-temperature superconductor. We conclude that this system has a cooperative, simultaneous-melting/oxygen desorption/metal-insulator transition that occurs near 900°C. We speculate on its nature and on its relationship to phenomena found in other high-T c superconductors.  相似文献   
83.
Extracellular ATP (eATP) has long been established in animals as an important signalling molecule but this is less understood in plants. The identification of Arabidopsis thaliana DORN1 (Does Not Respond to Nucleotides) as the first plant eATP receptor has shown that it is fundamental to the elevation of cytosolic free Ca2+ ([Ca2+]cyt) as a possible second messenger. eATP causes other downstream responses such as increase in reactive oxygen species (ROS) and nitric oxide, plus changes in gene expression. The plasma membrane Ca2+ influx channels involved in eATP-induced [Ca2+]cyt increase remain unknown at the genetic level. Arabidopsis thaliana Annexin 1 has been found to mediate ROS-activated Ca2+ influx in root epidermis, consistent with its operating as a transport pathway. In this study, the loss of function Annexin 1 mutant was found to have impaired [Ca2+]cyt elevation in roots in response to eATP or eADP. Additionally, this annexin was implicated in modulating eATP-induced intracellular ROS accumulation in roots as well as expression of eATP-responsive genes.  相似文献   
84.
Grain legumes are important crops, but they are salt sensitive. This research dissected the responses of four (sub)tropical grain legumes to ionic components (Na+ and/or Cl) of salt stress. Soybean, mungbean, cowpea, and common bean were subjected to NaCl, Na+ salts (without Cl), Cl salts (without Na+), and a “high cation” negative control for 57 days. Growth, leaf gas exchange, and tissue ion concentrations were assessed at different growing stages. For soybean, NaCl and Na+ salts impaired seed dry mass (30% of control), more so than Cl salts (60% of control). All treatments impaired mungbean growth, with NaCl and Cl salt treatments affecting seed dry mass the most (2% of control). For cowpea, NaCl had the greatest adverse impact on seed dry mass (20% of control), while Na+ salts and Cl salts had similar intermediate effects (~45% of control). For common bean, NaCl had the greatest adverse effect on seed dry mass (4% of control), while Na+ salts and Cl salts impaired seed dry mass to a lesser extent (~45% of control). NaCl and Na+ salts (without Cl) affected the photosynthesis (Pn) of soybean more than Cl salts (without Na+) (50% of control), while the reverse was true for mungbean. Na+ salts (without Cl), Cl salts (without Na+), and NaCl had similar adverse effects on Pn of cowpea and common bean (~70% of control). In conclusion, salt sensitivity is predominantly determined by Na+ toxicity in soybean, Cl toxicity in mungbean, and both Na+ and Cl toxicity in cowpea and common bean.  相似文献   
85.
Cardiovascular disease is the leading cause of mortality and morbidity around the globe, creating a substantial socio-economic burden as a result. Myocardial infarction is a significant contributor to the detrimental impact of cardiovascular disease. The death of cardiomyocytes following myocardial infarction causes an immune response which leads to further destruction of tissue, and subsequently, results in the formation of non-contractile scar tissue. Macrophages have been recognized as important regulators and participants of inflammation and fibrosis following myocardial infarction. Macrophages are generally classified into two distinct groups, namely, classically activated, or M1 macrophages, and alternatively activated, or M2 macrophages. The phenotypic profile of cardiac macrophages, however, is much more diverse and should not be reduced to these two subsets. In this review, we describe the phenotypes and functions of macrophages which are present in the healthy, as well as the infarcted heart, and analyze them with respect to M1 and M2 polarization states. Furthermore, we discuss therapeutic strategies which utilize macrophage polarization towards an anti-inflammatory or reparative phenotype for the treatment of myocardial infarction.  相似文献   
86.
采用高温淬火方法制备了Tc在27.4K至92.4K之间的一组不同氧含量的PMP(粉末熔融工艺)法YBCO超导体。通过对这些超导体样品的磁滞回线及不可逆线的研究发现,随着氧空位的增加,超导体的磁通钉扎力减小  相似文献   
87.
杂原子掺杂碳基氧还原(ORR)催化剂具有代替Pt基催化剂的巨大潜力。以硫掺杂g-C3N4(S-doped g-C3N4, S-g-C3N4)作为硫源和氮源,以三嵌段共聚物P123作为碳源,通过简单的高温热解法成功制备了N、S共掺杂碳(N, S co-doped carbon, NSC)催化剂,并考察了热解温度对制备的NSC催化剂ORR性能的影响。材料表征结果显示:温度为1 000 ℃时制备的催化剂NSC-1000具有较高的氮含量和硫含量及最大的比表面积;电化学测试结果显示:NSC-1000具有最佳的ORR性能,在0.1 mol/L KOH溶液中半波电位(half-wave potential, E1/2)高达0.888 V,且经10 000圈循环伏安扫描后E1/2仅负移12 mV,表现出极佳的活性和稳定性。此外,旋转环盘电极测试结果显示:NSC-1000催化剂主要以四电子反应路径催化ORR的发生。本实验为制备N、S共掺杂碳基高效ORR催化剂提供了新的思路。  相似文献   
88.
In the chemical looping with oxygen uncoupling (CLOU) process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combustion rate of carbon is faster than the decoupling rate of oxygen carrier (OC).Hence,high tem-perature tolerance and rapid oxygen release rate of CuO modified by three different ores were investi-gated in this study.The kinetics analysis of oxygen decoupling with Cu-based oxygen carriers was also evaluated.Results showed that CuO modified by chrysolite had faster oxygen release rate than that of CuO.Limestone showed obvious positive effect on the oxidization process.The selected OCs could keep stable in at least 20 cycles,for about 1200 min.Shrinking core model (SCM) fitted well for the decoupling process in the temperature range of 1123-1223 K.Reduction rate kinetic information may aid in the development of chemical looping with oxygen uncoupling (CLOU) technologies during reactor design and process modeling.Ternary doped copper oxide with chrysolite and limestone could improve the reactivity of CuO in decoupling and coupling process and also improve the high temperature tolerance.  相似文献   
89.
采用一种简单易行的共沉淀法合成了前驱体镍铁普鲁士蓝类似物NiFe-PBA(NF),然后通过溶剂热处理获得了镍铁普鲁士蓝纳米多孔材料(NFP)。通过XRD、SEM、TEM、XPS、BET及电化学方法对所得材料进行了结构表征和析氧性能测试。结果表明,NFP相对于前驱体NF,电化学比表面积增大、催化活性位点增多,电催化析氧反应(OER)性能显著提高。在浓度1 mol/L KOH水溶液中,达到10 mA/cm2电流密度时,NFP所需过电位仅为260 mV,比NF(320 mV)前驱体低18.75%,也优于大多数已报道的非贵金属催化剂和商用贵金属催化剂,显示出良好的应用前景。  相似文献   
90.
Disulfiram (DSF), an irreversible aldehyde dehydrogenase inhibitor, is being used in anticancer therapy, as its effects in humans are known and less adverse than conventional chemotherapy. We explored the potential mechanism behind the cytotoxicity of DSF-Cu+/Cu2+ complexes in oral epidermoid carcinoma meng-1 (OECM-1) and human gingival epithelial Smulow-Glickman (SG) cells. Exposure to CuCl2 or CuCl slightly but concentration-dependently decreased cell viability, while DSF-Cu+/Cu2+ induced cell death in OECM-1 cells, but not SG cells. DSF-Cu+/Cu2+ also increased the subG1 population and decreased the G1, S, and G2/M populations in OECM-1 cells, but not SG cells, and suppressed cell proliferation in both OECM-1 and SG cells. ALDH enzyme activity was inhibited by CuCl and DSF-Cu+/Cu2+ in SG cells, but not OECM-1 cells. ROS levels and cellular senescence were increased in DSF-Cu+/Cu2+-treated OECM-1 cells, whereas they were suppressed in SG cells. DSF-Cu+/Cu2+ induced mitochondrial fission in OECM-1 cells and reduced mitochondrial membrane potential. CuCl2 increased but DSF- Cu2+ impaired oxygen consumption rates and extracellular acidification rates in OECM-1 cells. CuCl2 stabilized HIF-1α expression under normoxia in OECM-1 cells, and complex with DSF enhanced that effect. Levels of c-Myc protein and its phosphorylation at Tyr58 and Ser62 were increased, while levels of the N-terminal truncated form (Myc-nick) were decreased in DSF-Cu+/Cu2-treated OECM-1 cells. These effects were all suppressed by pretreatment with the ROS scavenger NAC. Overexpression of c-Myc failed to induce HIF-1α expression. These findings provide novel insight into the potential application of DSF-CuCl2 complex as a repurposed agent for OSCC cancer therapy.  相似文献   
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