Two new Protecting Groups for the Guanidino Function of arginine

Two new synthons, Fmoc-L-Arg(biphenyl-4-sulphonyl)-OH ( 8 ) and Fmoc-Arg(4-methoxy-3-t-butylbenzenesulphonyl)-OH ( 14 ), are prepared for the synthesis of arginine-containing peptides. These groups are cleaved by commonly employed trifluoroacetic acid and methanesulphonic acid. Kinetic studies reveal that extended bicyclic aromatic conjugation, as in biphenyl, slightly improves the acid lability compared to the electron-donating t-butyl group.     

Radiation induced decontamination of Cr(Ⅵ), Cu(Ⅱ) and phenol in some tannery effluents

Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high concentrations of Cr(Ⅵ) (2.7-12.6 mg/L), Cu(Ⅱ) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A new technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(Ⅵ), Cu(Ⅱ) and phenol associated with tannery effluents to the permitted values. It was observed that concentration of Cr(Ⅵ) in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy. A radiation dose of 2.5 kGy was required to remove more than 95% of Cu(Ⅱ) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose.     

Hypocholesterolaemic effect of yoghurt containing Bifidobacterium pseudocatenulatum G4 or Bifidobacterium longum BB536

The effect of a yoghurt supplement containing Bifidobacterium pseudocatenulatum G4 or Bifidobacterium longum BB536 on plasma lipids, lipid peroxidation and the faecal excretion of bile acids was examined in rats fed a cholesterol-enriched diet. After 8 weeks, the rats in the positive control (PC) group who were fed the cholesterol-enriched diet showed significant increases in plasma total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and malondialdehyde (MDA). However, groups fed a cholesterol-enriched diet supplemented with yoghurt containing B. pseudocatenulatum G4 or B. longum BB536 had significantly lower plasma TC, LDL-C, very-low-density lipoprotein (VLDL) cholesterol, and MDA than had the PC group after 8 weeks of treatment. In addition, faecal excretion of bile acids was markedly increased in the rats fed the yoghurt containing B. pseudocatenulatum G4 or B. longum BB536 as compared to the PC and NC groups.     

Specific Heat of Olive Oil to 356 MPa

We measured the velocity of sound in olive oil under pressure with the Brillouin light scattering technique. Using the values for the density and the thermal conductivity that have only recently been reported, we calculated the adiabatic compressibility and the isobaric specific heat up to 356 MPa and the thermal diffusivity up to 200 MPa. The specific heat displays a maximum at 124 MPa, suggesting a possible phase transition around this pressure. Apart from the theoretical and practical importance of these results for the food industry and beyond, this work shows that Brillouin light scattering and macroscopic methods are complementary and can be employed to measure thermophysical parameters of food liquids under pressure.     

Lipoprotein Subfraction Profile and HDL-Associated Enzymes in Sickle Cell Disease Patients

Although hypocholesterolemia is a reported finding in sickle cell disease (SCD), low-density lipoprotein (LDL)/high-density lipoprotein (HDL) subfractions and HDL-associated enzymes have not been determined in SCD patients. Blood was collected from 38 hemoglobin (Hb)A volunteers and 45 homozygous HbSS patients who had not received blood transfusions in the last 3 months. Serum lipids were measured by automated analyzer while LDL and HDL subfraction analysis was done by continuous disc polyacrylamide gel electrophoresis. Serum levels of cholesteryl ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT), apolipoprotein B (apoB) and apolipoprotein A-1 (apoA-I) were determined by enzyme-linked immunosorbent assay (ELISA). Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were significantly decreased, while TG levels were significantly increased in SCD patients compared to controls. A significant decrease in intermediate-density lipoprotein (IDL)-C, IDL-B, IDL-A and LDL-1 fractions were seen in SCD patients, while no significant difference was observed in small dense LDL particles. A significant decrease was seen in HDL-large, HDL-intermediate and HDL-small fractions in SCD patients versus controls. Levels of LCAT and ApoA-1 protein measured in SCD patients were significantly lower while no significant difference was observed in CETP and ApoB protein levels compared to controls. The reduction observed in LDL- and HDL-C in SCD patients was reflected as significantly decreased IDL, LDL-1 and HDL-subfractions. Decreased HDL subfractions may possibly lead to the reduced ApoA-1 and LCAT protein levels observed in SCD patients.     

LOW TEMPERATURE OXIDATION OF LOW RANK COALS

The low temperature oxidation of a Montana subbituminous coal was investigated using round bottom 100 ml flasks in constant temperature baths. The experiments were carried out in normal and oxygen enriched air at 30°C, 45°C and 70°C with particle sizes ranging from 4 mesh to 100 mesh. Periodic analysis of gas samples from the flasks provided the rate data. The reactivity of the as received coal was compared with that of the same coal dried (i) in high pressure steam and (ii) in hot water

A rate equation has been proposed incorporating the effects of oxygen diffusion and surface reaction. For higher oxygen concentration and smaller particle sizes, the zero order surface reaction was found to be controlling. The temperature dependency of the reaction rate was found to be well represented by the Arrhenius equation. The activation energy varied slightly under various conditions between 15 to 20 kca)/g mole

The reactivity of the hot water dried coal was found to be similar to that of the as received coal. Steam dried coal however, was found to be much less reactive.     

Mechanism of boron tribromide electroreduction

This study was carried out to investigate the electrochemical behavior of boron tribromide in dimethlyformamide. The reduction of the compound was found to follow a CE mechanism. The kinetic parameters and the diffusion coefficient were calculated by the use of ultramicrodisc electrodes and chronoamperometry. The number of electrons transferred was found to be 2 by rotating disc and ultramicro disc electrodes and 3 by coulometry. These results are in good accordance with those obtained from molten boron salts. This study is important in regard to electrochemical boronizing at low temperatures.     

Optimization of design and operating parameters in a pilot scale Jameson cell for slime coal cleaning

The Jameson flotation cell has been commonly used to treat a variety of ores (lead, zinc, copper etc.), coal and industrial minerals at commercial scale since 1989. It is especially known to be highly efficient at fine and ultrafine coal recovery. However, although the Jameson cell has quite a simple structure, it may be largely inefficient if the design and operating parameters chosen are not appropriate. In this study, the design and operating parameters of a pilot scale Jameson cell were optimized to obtain a desired metallurgical performance in the slime coal flotation. The optimized design parameters are the nozzle type, the height of the nozzle above the pulp level, the downcomer diameter and the immersion depth of the downcomer. Among the operating parameters optimized are the collector dosage, the frother dosage, the percentage of solids and the froth height. In the optimum conditions, a clean coal with an ash content of 14.90% was obtained from the sample slime having 45.30% ash with a combustible recovery of 74.20%. In addition, a new type nozzle was developed for the Jameson cell, which led to an increase of about 9% in the combustible recovery value.