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Joe Phua 《The Journal of communication》2013,63(5):933-952
This study examined members of health issue-specific social networking sites (SNSs) for smoking cessation, hypothesizing that social identification, bridging and bonding social capital, perceived subjective norms, and social support would impact the relationship between participation and smoking cessation self‐efficacy. Results (N = 252) of an online questionnaire revealed that participation significantly influenced each social factor, which in turn resulted in greater smoking cessation self-efficacy. By applying and extending traditional peer influence theories, a structural model predicting 5 underlying mechanisms of social interconnectedness that influence perceived behavioral control for quitting smoking was tested and supported. Implications for future research on health issue-specific SNSs are discussed. 相似文献
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DONG Hong-bo LI Guo-dong WANG Shao-feng FU Xue-qi ZHAO Zhi-zhuang Joe 《Canadian Metallurgical Quarterly》2011,27(2)
Protein tyrosine phosphatases(PTPs) are crucial regulators of signal transduction. Among them,PTP-MEG2 is an intracellular enzyme of 593 amino acid residues with a putative lipid-binding domain at the N-terminus. In the present study, we cloned the full-length form of the enzyme and expressed it in E. coli cells as a 6xHis-tagged protein. The majority of the expressed enzyme was found in the inclusion body of E. coli cell extracts.Upon extraction with a buffer containing urea, the recombinant enzyme was purified to near homogeneity on a single Ni-NTA-agarose column. This procedure resulted in the production of over 100 mg of purified recombinant PTP-MEG2 from 1 L E. coli cell culture. The purified protein displayed a single polypeptide band with expected molecular size on SDS-polyacrylamide gel electrophoresis under reducing conditions. Isolated under denatured conditions in urea, the purified enzyme was re-natured by dialyzing against a refolding buffer. The re-natured enzyme effectively dephosphorylated the common PTP substrate para-nitrophenylphosphate with a specific activity of 2000units/mg. Meanwhile, the denatured enzyme was used to immunize a rabbit to produce antibodies. The resulting antiserum had extremely high sensitivity and specificity. When used for Western blot analysis, the anti-serum revealed a wide expression of PTP-MEG2 in many tissues of mice. Together, we developed a highly effective way to purify a large amount of PTP-MEG2 and generated highly sensitive antibodies that can specifically detect endogenous expression of the enzyme in tissues. 相似文献
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Jing Zheng Scott P. Beckman Joe N. Gray Mufit Akinc 《Journal of the American Ceramic Society》2001,84(9):1961-1967
X-ray tomography has been used to investigate the density variations in SiC joints formed using polymer pastes. It has been demonstrated that X-ray tomography provides accurate bulk density measurements and volumetric density gradients. The results suggest that the magnitude of the applied pressure after green state joining and the amount of polymer (polycarbosilane, PCS) in the joining pastes influence the green density of the joints. All joints are prepared and applied in air atmosphere and at room temperature. The green densities of the joints increase from 54% to 66% of theoretical with the increase of the applied pressure from ambient to 138 MPa. Highest joint density without applied pressure is achieved using paste containing 50 vol% PCS. Furthermore, allylhydridopopolycarbosilane- (AHPCS-) containing pastes resulted in higher densities at the joint–matrix interface, indicating infiltration of polymer into the matrix. 相似文献
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Priscilla A. Selembo Joe M. Perez Wallis A. Lloyd Bruce E. Logan 《International Journal of Hydrogen Energy》2009
The use of glycerol for hydrogen gas production was examined via electrohydrogenesis using microbial electrolysis cells (MECs). A hydrogen yield of 3.9 mol-H2/mol was obtained using glycerol, which is higher than that possible by fermentation, at relatively high rates of 2.0 ± 0.4 m3/m3 d (Eap = 0.9 V). Under the same conditions, hydrogen was produced from glucose at a yield of 7.2 mol-H2/mol and a rate of 1.9 ± 0.3 m3/m3 d. Glycerol was completely removed within 6 h, with 56% of the electrons in intermediates (primarily 1,3-propanediol), with the balance converted to current, intracellular storage products or biomass. Glucose was removed within 5 h, but intermediates (mainly propionate) accounted for only 19% of the electrons. Hydrogen was also produced using the glycerol byproduct of biodiesel fuel production at a rate of 0.41 ± 0.1 m3/m3 d. These results demonstrate that electrohydrogenesis is an effective method for producing hydrogen from either pure glycerol or glycerol byproducts of biodiesel fuel production. 相似文献
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