Biosorption studies of nickel on Parthenium hysterophorous ash.

The application of an aquatic weed, Parthenium hysterophorous, has been investigated for the removal of nickel from aqueous solutions. Parthenium hysterophorous, the weed was converted to ash and was used as an adsorbent for the removal of nickel(II) from aqueous solutions at different experimental conditions. The per cent removal of Ni increased from 67.30 to 97.54%, with the nickel(II) concentration decreasing from 477.21 to 67.83 mg L(-1) at 25 degrees C, pH 11.0. The removal was favoured at higher pH, with a maximum removal at pH 11.0. The effects of concentration and temperature are also reported. Batch adsorption kinetics are described by the Lagergren equation. The value of the rate constant of adsorption was found to be 6.82 x 10(-2) min(-1) at 67.83 mg L(-1) and 25 degrees C. The applicability of the Langmuir and Freundlich equations for the present system were tested at different temperatures, viz. 25, 50 and 75 degrees C, and the constants were calculated. Thermodynamic parameters indicate the exothermic nature of nickel(II) adsorption on P. hysterophorous ash. The adsorption capacity was found to be much better than other common adsorbents reported for the removal of nickel(II).

Relationship between NMR relaxation characteristics and water activity in cereal leaves.

The relationship of imposed water activity a(w) (equilibrium relative humidity) with conventional water status parameters and proton spin-lattice relaxation time T1 of leaf water was studied in pearl millet and wheat. The water activities of different levels were created by equilibrating the leaves in varying concentrations of PEG-6000 solutions. With decreasing a(w), relative water content and T1 decreased linearly and other variables (leaf water potential and leaf water content) decreased exponentially upto a dehydration level of a(w) approximately 0.978 for pearl millet, 0.986 for drought susceptible wheat var. HD2329 and 0.975 for tolerant wheat var. C306. Below that level there was abrupt reduction in all parameters except T1 which registered an increase. The changes in short and long components of T1 with changes in a(w) have also have been discussed for pearl millet.

Cholecystectomy and a simple technique of operative cholangiography.

A simple, easily reproducible technique of operative cholangiography is described. The technique has three advantages: (a) there is no need to divide or ligate the cystic duct; (b) it demonstrates the cystic duct anatomy clearly and is particularly useful in demonstrating stones in that duct thus eliminating the hazard of the retained stone in the cystic duct stump; (c) it is possible to eliminate the problem of false positives due to air bubbles. A consecutive series of 442 cholecystectomy patients is reviewed. The overall operative mortality was 1.6 per cent; no death could be attributed to operative cholangiography. Thirty-five of 324 patients (10.8 per cent) with gallstones and no history of jaundice were shown to have unexpected abnormalities in the common bile duct.

Short-stay surgery for inguinal hernia. Clinical outcome of the Shouldice operation.

In 1970 a general surgical team on Teesside adopted the Shouldice operation for inguinal hernia together with a policy of short-stay surgery. Careful follow-up has established that repairs using the suture material of choice--stainless-steel wire--have an estimated 6-year recurrence-rate of 0.8%, statistically indistinguishable from that achieved by the highly specialised Shouldice Clinic. However, the recurrence-rate 2 years after suturing with an alternative polyester-based material is estimated at 8.1%--a figure much more in keeping with rates reported by general surgeons using traditional methods.