Hydrogen transport in alpha titanium

Permeation experiments after nitriding the inlet surface of a hollow cylindrical membrane were conducted. Permeation data on two additional specimens given pre-oxidation or pre-nitriding treatments at both inlet and outlet surfaces are presented in terms of Arrhenius plots. Additionally, an analysis of geometry dependence on permeation rate was made for several specimens including the ones mentioned above. For simplicity in this report, the term as-polished is used to refer to a specimen which is either as-polished or is as-polished, pre-oxidized and annealed

Gas phase hydrogen permeation in alpha titanium and carbon steels

Commercially pure titanium and heats of Armco ingot iron and steels containing from 0.008-1.23 w/oC were annealed or normalized and machined into hollow cylinders. Coefficients of diffusion for alpha-Ti and alpha-Fe were determined by the lag-time technique. Steady state permeation experiments yield first power pressure dependence for alpha-Ti and Sievert's law square root dependence for Armco iron and carbon steels. As in the case of diffusion, permeation data confirm that alpha-titanium is subject to at least partial phase boundary reaction control while the steels are purely diffusion controlled. The permeation rate in steels also decreases as the carbon content increases. As a consequence of Sievert's law, the computed hydrogen solubility decreases as the carbon content increases. This decreases in explained in terms of hydrogen trapping at carbide interfaces. Oxidizing and nitriding the surfaces of alpha-titanium membranes result in a decrease in the permeation rate for such treatment on the gas inlet surfaces but resulted in a slight increase in the rate for such treatment on the gas outlet surfaces. This is explained in terms of a discontinuous TiH2 layer

Risk of hypertension with bevacizumab, an antibody against vascular endothelial growth factor A: a systematic review and meta-analysis

Bevacizumab, a humanized antibody against VEGF, is effective in the treatment of patients with many cancers. However, as with many therapeutic agents, significant side effects are associated with bevacizumab, Hypertension is one of the predominant toxicity. We performed a systematic review and meta-analysis of published clinical trials of bevacizumab to quantify the risk of hypertension. 15 studies following PRISMA guidelines and matching inclusion and exclusion criteria were collected in which a group of patients were either treated with Bevacizumab and a concurrent chemotherapy and another group treated with Placebo and the same chemotherapy. Relative risk (RR) was calculated. P<0.05 was considered statistically significant. RevMan 5.3 software was used for the analysis. A total of 13,070 patients were included. Bevacizumab was associated with a significant increased risk of overall hypertension (RR=3.509; 95% C.I:2.451 to 5.023). 11 trials are included for determining the risk of Grade 3 hypertension including 8799 patients with a significant increased risk (RR=3.909; 95%C.I:1.983 to 7.707). 7 trials are included for determining the risk of hypertension at low dose (2.5 mg/kg/cycle) including 3691 patients associated with a significant increased (RR=2.640; 95%C.I: 1.408 to 4.950). 10 trials are included for determining the risk of hypertension at high dose (5 mg/kg/cycle) including 9379 patients associated with a significant (RR=4.036; 95%C.I: 2.948 to 5.525). Our meta-analysis has demonstrated that bevacizumab may be associated with a significantly increased risk of hypertension in patient with a variety of metastatic solid tumors irrespective of dosing