The determination of insulin in plasma and urine

Thesis (M.A.)--Boston UniversityWe have tried to determine insulin in urine and plasma by means of aminoguanidine sulfate solution. The urine and plasma are cleared with Somogyi reagent. The filtrate is then diluted with water to the range of the aminoguanidine sulfate reagent. Our only difficulty lies in the compliance of the curves to Beer's law. The curves tend to give less color in the higher concentrations and more color in the lower concentrations thus the curves do not pass through or near the origin. It is our fond hope that if the Beer's law plots were straightened out the determination would be successful. By running determinations simultaneously at two different temperatures, it would then be possible to determine insulin and only insulin

Direct 3D Printing of Silica Doped Transparent Magnesium Aluminate Spinel Ceramics

Transparent magnesium aluminate spinel ceramics were additively manufactured via a laser direct deposition method in this study. With a minimum porosity of 0.3% achieved, highly transparent spinel samples with the highest total optical transmittance of 82% at a wavelength of 632.8 nm, were obtained by a 3D printing approach. However, cracking was found to be a major issue affecting printed spinel samples. To control prevalent cracking, the effect of silica dopants was investigated. Increased silica dopants reduced average total crack length by up to 79% and average crack density by up to 71%. However, a high dopant level limited optical transmission, attributed to increased porosity and formation of secondary phase. Further investigation found that with decreased average fracture toughness, from 2.4 MPa·m1/2 to 1.9 MPa·m1/2, the obvious reduction in crack formation after doping was related to decreased grain size and introduction of softer secondary phase during deposition. The study demonstrated the feasibility of the proposed laser direct deposition method in directly fabricating transparent spinel ceramics while dopants showed potentials in addressing cracking issues

A randomized trial of intravenous and oral iron in chronic kidney disease

Although iron is commonly used to correct iron deficiency anemia (IDA) in chronic kidney disease (CKD), its effect on kidney function is unclear. To assess this, we randomly assigned patients with stage 3 and 4 CKD and IDA to either open-label oral ferrous sulfate (69 patients to 325 mg three times daily for 8 weeks) or intravenous iron sucrose (67 patients to 200 mg every 2 weeks, total 1 g). The primary outcome was the between-group difference in slope of measured glomerular filtration rate (mGFR) change over two years. The trial was terminated early on the recommendation of an independent data and safety monitoring board based on little chance of finding differences in mGFR slopes, but a higher risk of serious adverse events in the intravenous iron treatment group. mGFR declined similarly over two years in both treatment groups (oral -3.6 ml/min per 1.73 m(2), intravenous -4.0 ml/min per 1.73 m(2), between-group difference -0.35 ml/min per 1.73 m(2); 95% confidence interval -2.9 to 2.3). There were 36 serious cardiovascular events among 19 participants assigned to the oral iron treatment group and 55 events among 17 participants of the intravenous iron group (adjusted incidence rate ratio 2.51 (1.56-4.04)). Infections resulting in hospitalizations had a significant adjusted incidence rate ratio of 2.12 (1.24-3.64). Thus, among non-dialyzed patients with CKD and IDA, intravenous iron therapy is associated with an increased risk of serious adverse events, including those from cardiovascular causes and infectious diseases

To debt or not to debt : are Islamic banks less risky than conventional banks?

We empirically analyze the market risk profiles of Islamic banks with two sets of conventional banks taken from the same geographical locations as Islamic banks and from a random global sample respectively for the period 2000-2013. Moreover, we divided our sample period into pre-financial crisis, during financial and post financial crisis. Estimates of Value-at-Risk (VaR) and Expected Shortfall (ES) which incorporates losses beyond VaR are used as market risk measures for both univariate and multivariate portfolios. Our key input is the share price by market capitalization of publicly traded banks of similar size in Islamic and non-Islamic countries. Univariate analysis finds no discernible differences between Islamic and conventional banks. However, dynamic correlations obtained via a multivariate setting shows Islamic banks to be less riskier for both sets of conventional banks; and especially so during the recent global financial crisis. The policy implications are: (i) that the inclusion of Islamic banks within asset portfolios may mitigate potential risk; (ii) that the Basel committee should consider the ES measure of risk for Islamic banks in preference to the current VaR methodology, which over-estimates the market risk of Islamic banks

Effects of Zirconia Doping on Additively Manufactured Alumina Ceramics by Laser Direct Deposition

The ability to additively manufacture functional alumina ceramics has the potential to lower manufacturing costs and development time for complex components. In this study, the doping effects of zirconia on laser direct deposited alumina ceramics were investigated. The microstructure of the printed samples was analyzed in terms of grain size and composition distribution. The addition of zirconia was found to accumulate along alumina grain boundaries and resulted in significant grain refinement. The zirconia doping largely reduced crack formation during processing compared to that of pure alumina samples. In the case of 10 wt% zirconia, cracking during deposition was nearly completely eliminated, but meanwhile porosity was increased. Through grain refinement and crack reduction in 10 wt% zirconia samples, bending strength was shown to increase by nearly four times the value obtained with pure alumina. Fracture toughness was also shown to increase by 1.5 times with addition of 5 wt% zirconia, which was attributed to the crack interaction with zirconia doped grain boundary and stress induced tetragonal to monoclinic transformation of zirconia. These findings indicated the potentials of dopants during laser direct deposition of ceramics and can further be used to tailor the properties of additively manufactured ceramic components

Origin of Afferent Projections into Bovine Chromaffin Cell Implants in the Rat Periaqueductal Gray Determined by Retrograde and Anterograde Tracing

We have previously described long-term survival of isolated bovine chromaffin cell suspension grafts in the periaqueductal gray of adult rats. Electron microscopic analysis of the graft sites revealed synapses on the transplanted chromaffin cells. The origin of these synapses is not known, but they are probably derived from the host since the initial grafts were suspensions of chromaffin cells that were essentially free of other cell types