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Abstract: The depleting fossil fuels with their ever increasing prices have paved ways for alternative fuels. Biodiesel is one of those alternative fuels which have picked up keen interest of the people due to its similar properties to diesel. However due to biodiesel being costlier than diesel in the present scenario, it has not been preferred to diesel. However if the cost of biodiesel is reduced then its effective usage can be made, either by blending with conventional diesel or by utilizing its byproduct (glycerol) effectively. One way is to use glycerol to produce hydrogen. Hydrogen, being another source of renewable energy, is also seen as a clean fuel for transportation purpose. Hydrogen can be prepared through glycerol via various routes namely steam reforming, auto-thermal reforming, partial oxidation, etc. The paper here focuses on the steam reforming process. This process is used widely used in the industries and it would not require much change in the system if the feedstock is changed to glycerol from naphtha or natural gas. However like every process this process also has some limitations which hinder the effective production of hydrogen. The paper throws light on these challenges, along with few possible solutions which can be used in order to avoid or eliminate these challenges and help in efficient production of hydrogen. [Copyright &y& Elsevier]

Experimental glomerulonephritis induced by heterologous GBM immunization in mice is temporarily prevented and reduced in severity when ATG is administered prior to or in conjunction with GBM. Once the disease is well established, ATG does not appear to significantly alter glomerular damage. [ABSTRACT FROM AUTHOR]

Mice immunized with dog glomerular basement membrane in Fruend's complete adjuvant uniformly developed severe renal lesions. A prominent event in many animals appeared to be mononuclear cell accumulation around small renal blood vessels. Glomerular lesions characterized by hypercellularity, thickening of basement membrane, necrosis, and well marked crescent formation were noted. Immunofluoresecnt and antibody elution studies from the kidneys of animals immunized with dog GBM demonstrated the presence of specific anti-GBM antibody which could be detected in mouse glomeruli 4 weeks after initial immunization. [ABSTRACT FROM AUTHOR]

We investigated the predictors of serum albumin and the relationship between serum albumin and urea kinetic indices in continuous peritoneal dialysis (CPD). In a training set (TS) of 143 urea kinetic studies performed in 92 CPD patients, stepwise logistic regression identified high/high-average peritoneal solute transport, diabetes, advanced age and high daily drain volume normalized by body water as predictors of low serum albumin (< 35 g/liter). This analysis was then substantiated in a validation set (VS) of 187 kinetic studies performed in another 102 CPD patients. The calculated area under the receiver operating characteristic (ROC) curve by this logistic regression model was 0.782 (95% CI, 0.745 to 0.819). Logistic regression was repeated in the TS using only the first kinetic study from each patient, and it identified high/high-average peritoneal solute transport, diabetes, and advanced age as predictors of low albumin. Using only the first kinetic study from each patient in the VS, the second logistic regression model calculated an area under the ROC curve equal to 0.850 (95% CI, 0.810 to 0.890). The relative risk (RR) of serum albumin < 35 g/liter was computed for all kinetic studies after combining the TS and the VS and using non-diabetic CPD subjects aged < or = 61 years with low/low average peritoneal solute transport as the reference group. The RR with only one risk factor present ranged from 1.076 (age > 61 years) to 6.792 (high/high-average transport). The RR with two risk factors present ranged from 5.200 to 9.729. The RR with all three risk factors present was 9.100 (95% CI, range 3.923 to 21.111). A subset of 37 CPD patients had a second urea kinetic study 8 +/- 5 months after an increase in the amount of dialysis due to low urea clearance and/or uremic symptoms. The weekly KT/V urea increased from 1.40 +/- 0.24 to 2.10 +/- 0.31 after the increase in the CPD dose. With the increase in dialysis, the protein catabolic rate increased substantially; however, the mean serum albumin remained stable (from 33.9 +/- 4.6 to 33.3 +/- 6.2 g/liter; decrease 18; increase 15; same 4). In comparison to the subjects who had a decrease in serum albumin after the increase in KT/V, those with the increase in serum albumin were younger (44.2 +/- 11.2 vs. 54.3 +/- 16.2 years, P = 0.044) and had a higher serum urea after the increase in the dose of CPD (22.4 +/- 7.8 vs. 17.0 +/- 6.0 mmol/liter, P = 0.037). We conclude that the major predictors of low serum albumin in CPD are advanced age, diabetes, and high/high-average peritoneal solute transport, but not urea kinetic studies. An increase in the dose of dialysis does not cause a consistent rise in serum albumin in underdialyzed CPD subjects. However, a subset of younger patients may be able to increase their serum albumin in response to the increase in KT/V.

Anionic sites have been demonstrated in the basement membranes of peritubular capillaries. The anionic barrier function of peritubular capillary wall has been ascribed to these sites. Fenestrated capillaries in other organs have anionic sites in the endothelial cell glycocalyx and at the luminal surface of the fenestral diaphragms. The purpose of this study was to map anionic sites at the luminal surface of peritubular capillaries and to assess whether a concentration gradient for albumin exists across the endothelium. Partial chemical characterization of these anionic sites was done by in vivo enzymatic degradation. The difference in distribution of albumin following enzyme digestion was also studied. The binding of cationized ferritin to the luminal surface indicated that the rat peritubular capillaries have anionic sites along the entire luminal surface of the endothelial cell, including the fenestral diaphragms. Partial biochemical characterization of these sites shows that the sites in the glycocalyx are mainly from neuraminic acid, while the fenestral diaphragms have mainly heparan sulfate proteoglycans. Intravascular albumin extended to the endothelial luminal plasmalemma and to the luminal surface of fenestral diaphragms. Digestion with heparitinase was associated with the leakage of albumin outside the capillary wall. These findings suggest that the anionic surface of fenestrae constitutes a charge barrier of the peritubular capillaries.

Severe hyperkalemia (serum potassium level >6 mmol per liter [mEq per liter]), often with electrocardiographic disturbances, was noted at presentation in 30% of 73 hyperglycemic episodes (serum glucose concentration >25 mmol per liter [455 mg per dl]) observed in 15 in-hospital patients with insulin-dependent diabetes mellitus who were receiving long-term hemodialysis or peritoneal dialysis. Serum glucose concentration and total carbon dioxide content correlated significantly with the presenting serum potassium concentration. Treatment with parenteral insulin alone resulted in a decrease of the serum glucose value from 41 +/- 14 (standard deviation) to 11 +/- 5 mmol per liter (P <.001) and of serum potassium level from 5.2 +/- 1.2 to 4.0 +/- 0.6 mmol per liter (P <.001). The changes in serum glucose concentration and in carbon dioxide content and the serum potassium concentration at hyperglycemia were found to be independent correlates of the decrease in potassium concentration during treatment. Insulin alone resulted in correction of hyperkalemia in all instances. Posttreatment hypokalemia was noted in only two instances, each associated with both ketoacidosis and low-normal serum potassium concentration at hyperglycemia. Giving insulin is the only treatment usually needed for the hyperkalemia of hyperglycemia in patients on ongoing dialysis.

Noninvasive characterization of renal artery blood flow variables in the human has not been reported. Using a unique dual-frequency real-time two-dimensional echo Doppler (Duplex scanner) that was calibrated in vitro, we characterized renal artery blood flow patterns in 16 normal subjects (6 females). Calculated mean values of systolic diameter (Ds), maximal spatial average blood velocity (Vmsa), and volume flow rate (Q) were as follows: 4.5 +/- 0.6 mm right, 4.4 +/- 0.6 mm left; 67.6 +/- 9.4 cm . sec-1 right, 69.6 +/- 12.0 cm . sec-1 left; and 403 +/- 127 ml . min-1 right, 395 +/- 98 ml . min-1 left; respectively. Direct linear regression correlation of body surface area (BSA) with Ds and Q were statistically significant (P less than 0.01, r = 0.70; and P less than 0.01, r = 0.72, respectively). In a blind prospective series, six of seven angiographically normal renal arteries were noninvasively identified by normal geometry and blood velocity patterns. One angiographically normal artery was incorrectly classified as mildly stenotic. Eleven angiographically documented abnormal renal arteries were noninvasively identified by their abnormal blood flow patterns and/or geometry. This study suggests that dual-frequency Duplex scanning with careful sample volume control and Doppler audio spectra/blood velocity waveform analysis can be used to characterize blood flow variables in normal and diseased human renal arteries.

We evaluated the diagnostic accuracy of ultrasonic echo-Doppler velocimetry for the noninvasive diagnosis of renal artery stenosis. Renal artery stenosis was diagnosed if one or more of the following four abnormal hemodynamic parameters were found by Doppler velocimetry: (1) peak blood velocity greater than 100 cm . sec-1 in a focal area along the length of a renal artery, (2) absence of blood velocity during diastole, (3) absence of any detectable blood velocity denoting occlusion, or (4) broad-band Doppler frequency spectra due to focal blood velocity disturbances. With these criteria, the presence or absence of renal artery stenosis was blindly evaluated in 26 patients (52 arteries) who underwent standard or digital subtraction angiography. Compared to arteriography (reduction in diameter greater than or equal to 50%), the sensitivity of Doppler method was 89%, while its specificity was 73%. This noninvasive method may be useful in selecting patients for radiographic evaluation of renal artery stenosis and in the long term follow-up of these patients. Furthermore, echo-Doppler velocimetry may have the unique capability of assessing the hemodynamic consequences of renal artery stenosis.

We measured by affinity chromatography glycosylated hemoglobin levels in the blood of 43 diabetic and nondiabetic patients (139 measurements) on long-term dialysis therapy (continuous ambulatory peritoneal dialysis and hemodialysis) to determine the usefulness of this method of estimating glycemic control in diabetic persons on dialysis therapy. In nondiabetic patients, glycosylated hemoglobin levels were within the normal range (4.0% to 6.8% of total blood hemoglobin levels) for both continuous ambulatory peritoneal dialysis and hemodialysis. Glycosylated hemoglobin values correlated significantly with fasting blood glucose levels, serum urea levels, and serum total carbon dioxide content. By stepwise regression, fasting blood glucose values accounted statistically for .54 of the variability (R2) in glycosylated hemoglobin. The contribution of the other variables to this variability was minimal. In 9 diabetic patients (3 on hemodialysis), glycosylated hemoglobin levels correlated significantly with average daily blood glucose levels. Regression of the fasting blood glucose value on glycosylated hemoglobin was similar between continuous ambulatory peritoneal dialysis and hemodialysis. Measuring glycosylated hemoglobin levels by affinity chromatography is a suitable method for assessing glycemia in dialysis patients.