Adsorption of atrazine on selected vertisols and alfisols.

Adsorption of atrazine was studied on two Vertisols and two Alfisols varying in their physicochemical properties. Soils were equilibrated with various concentrations of atrazine using batch techniques. Adsorption affinity for atrazine was approximated by Freundlich constant (Kf), which is a measure of the strength or degree of adsorption. Kd values were calculated for atrazine despite some non-linearity in adsorption on both Vertisols and Alfisols. The Kd values are greater for Vertisols than Alfisols and increased with organic carbon content. Correlations were worked out between extent of adsorption and soil properties and were positively correlated with organic carbon (r = 0.688), clay content ( r = 0.712) and clay + organic carbon (r = 0.708). KOC values were calculated taking into account the organic carbon content for both Vertisols and Alfisols.

Ultrasound in the diagnosis of typhoid fever.

OBJECTIVES: To establish the efficacy of ultrasound (US) of the abdomen as a diagnostic test in Typhoid. To determine the ultrasound diagnostic criteria in cases of Typhoid. METHODS: The Widal test is the most commonly used method of detecting Typhoid fever, but does not provide results until a week after onset of fever due to the need for enough antibodies to develop to render a positive result. Abdominal Ultrasound was performed within three days of the onset of fever in 80 cases suspected to be having Typhoid fever. Subsequent follow-up scans were performed at five days, ten days and fifteen days. Subsequently, all 80 cases were found to be Widal positive and Salmonella culture was positive in 32 cases. We present our findings in 26 patients in the age group between 4 to 20 years in whom both Widal test and Salmonella culture was subsequently positive. RESULTS: The US findings were as follows: splenomegaly (n-26, 100%); Bowel wall thickening (n-22, 85%); mesenteric lymphadenopathy(n-20,77%); hepatomegaly with normal parenchymal echotexture (n-8, 31%); thickened gall bladder (n-16, 62%); biliary sludge (n-6, 23%); positive US Murphy's sign (n-7, 27%); pericholecystic edema with increased vascularity (n-6, 23%); mucosal ulceration in the wall of the gall bladder (n-1, 3.8%). CONCLUSION: In endemic areas like India, ultrasound findings of hepatomegaly, splenomegaly, ileal and cecal thickening, mesenteric lymphadenopathy and thick-walled gallbladder are diagnostic features of typhoid. Ultrasound can be a non-invasive, economical and a reasonably sensitive tool for diagnosing typhoid when serology is equivocal and cultures are negative.