Electrical passivation in hydrogen plasma exposed GaN

Lightly p-doped (3×10¹⁷ cm^-3) GaN grown on GaAs substrates by metal organic molecular beam epitaxy (MOMBE) shows deactivation of the residual acceptors on exposure to a microwave (2.45 GHz) hydrogen plasma at 250°C. Subsequent annealing to 350°C produces further dopant passivation, while higher temperatures (450°C) restore the initial conductivity. These results suggest that hydrogen carrier gases should be avoided during vapour phase growth of III-V nitrides     

Comparison of production of choriogonadotropin inhibitory protein, prolactin and insulin-like growth factor binding protein-1 by human decidua in vitro

BACKGROUND: Tissue plasminogen activator (tPA) is elevated in cancer patients and is thought to promote tumor angiogenesis by facilitating endothelial cell migration through plasmin-mediated degradation of extracellular matrix. Due to the presence of an epidermal growth factor (EGF)-finger domain in the tPA A-chain and the existence of an endothelial cell (EC) receptor that binds this domain, it was hypothesized that tPA has a direct receptor-mediated effect on EC proliferation, independent of plasmin. METHODS AND RESULTS: Using cultured canine ECs, tPA (7.25 microg/ml, approximately 107 nM) increased proliferation as much as 50 and 170% in the absence and presence of growth factors, respectively. tPA-induced increases in EC proliferation occurred independent of plasmin generation, as the plasmin inhibitor, aprotinin (10 microg/ml) did not inhibit tPA-induced proliferation. However, tPA-induced proliferation was inhibited dose-dependently to a maximum of 78% using a monoclonal antibody against the tPA EGF-finger domain. This antibody, known to inhibit tPA binding to its receptor, did not inhibit tPA-induced plasmin generation. To investigate the role of potential signal transduction pathways, ECs were exposed to lavendustin A, a tyrosine kinase inhibitor, at 33.5 microM (IC50 for basic fibroblast growth factor). Lavendustin A did not inhibit tPA-induced EC proliferation. However, Rp-cAMP, an inhibitor of cAMP-dependent kinases, specifically inhibited tPA-induced EC proliferation in a dose-dependent manner (IC50 = 50.5 microM). Pertussis toxin at maximal concentrations for this system (0.5 ng/ml) did not inhibit tPA-induced EC proliferation. CONCLUSION: These results lend support to the hypothesis that tPA may have a direct receptor-mediated effect on EC proliferation and that this effect occurs independent of plasmin and may be dependent upon protein kinase A activity.     

Clinical and experimental observation of xilixin granule combined with radiotherapy in treating malignant-tumors

Thirty six patients of pulmonary or nasopharyngeal carcinoma were treated with Xilixin granule (XLXG) combined with radiotherapy and compared their efficacy with that of 31 patients treated by Zhenqi Fuzheng granule combined with radiotherapy for control. Results showed that the symptoms of Yin Deficiency syndrome in treated group were obviously improved, the leucocyte decreased by 5.6%, while in control group it reached 25.8%, the 3 year survival rate was significantly higher in treated group (75.0%) than that in control group (51.6%). Animal experiment revealed that XLXG had the effects of tumor inhibition, it could increase white blood cells, platelets and hemoglobin of patients, especially in using large dosage. These results suggested that XLXG have some protective effect against radiotherapeutic damage in patients with malignant tumor.     

高性能小型扫描器

本文讨论了一种高性能小型扫描器的基本原理及扫描时序变换。对采用该小型扫描器的热成像系统也作了详细的介绍。该小型扫描器可满足多种用途。     

应用硫酸铵提高乌拉嗄金矿石浮选回收率试验研究

经试验发现应用一种化学肥料硫酸铵可以显著提高乌拉嘎金矿石的浮选回收率。闭路试验尾矿工艺矿物学鉴定证明，以硫酸铵作为调整剂的浮选过程中，微细粒单体金和金与石英边生体被有效回收。     

坑道用水下堵漏剂的研制

坑道水下堵漏剂的研制包括F－1、F－2和F－3型。其中F－1是一种有机堵漏剂，它可以在水中固化；F－2是一种无机防水堵漏剂，施工方便；F－3是速凝型，它可在瞬间固化，能对坑道的涌水口进行堵漏。     

Speed–accuracy tradeoff in Fitts’ law tasks—on the equivalency of actual and nominal pointing precision

Pointing tasks in human–computer interaction obey certain speed–accuracy tradeoff rules. In general, the more accurate the task to be accomplished, the longer it takes and vice versa. Fitts’ law models the speed–accuracy tradeoff effect in pointing as imposed by the task parameters, through Fitts’ index of difficulty (I_d) based on the ratio of the nominal movement distance and the size of the target. Operating with different speed or accuracy biases, performers may utilize more or less area than the target specifies, introducing another subjective layer of speed–accuracy tradeoff relative to the task specification. A conventional approach to overcome the impact of the subjective layer of speed–accuracy tradeoff is to use the a posteriori “effective” pointing precision W_e in lieu of the nominal target width W. Such an approach has lacked a theoretical or empirical foundation. This study investigates the nature and the relationship of the two layers of speed–accuracy tradeoff by systematically controlling both I_d and the index of target utilization I_u in a set of four experiments. Their results show that the impacts of the two layers of speed–accuracy tradeoff are not fundamentally equivalent. The use of W_e could indeed compensate for the difference in target utilization, but not completely. More logical Fitts’ law parameter estimates can be obtained by the W_e adjustment, although its use also lowers the correlation between pointing time and the index of difficulty. The study also shows the complex interaction effect between I_d and I_u, suggesting that a simple and complete model accommodating both layers of speed–accuracy tradeoff may not exist.