A substoichiometric radiochemical extraction method has been developed for the determination of cerium employing a chelating agent -hydroxy-naphthaldoxime, dissolved in isoamyl alcohol. The reagent was synthesised and characterised in our laboratory. The method developed was utilized to determine the cerium content of some natural samples.
Determination of mercury (II) by substoichiometric extraction with malonic anilide into a mixture of ether and MIBK is reported. The method has been applied in the estimation of the metal in industrial effluents.
A radiochemical procedure for separation of carrier-free22Na from bulk of Mg is described. The method involves the initial removal of bulk of Mg as Mg(OH)2 by means of ammonia followed by separation of the last traces of Mg by means of extraction with a cationic liquid exchanger,
di-(2-ethylhexyl) phosphoric acid (HDEHP) in cyclohexane.
Effect of Trichoderma viride T1433 on the pectolytic enzyme activity of Rhizopus stolonifer (= R. artocarpi) during the development of soft rot of jackfruit was studied. Activity of different fractions of pectolytic enzymes like PG, PME and PL was investigated during pathogenesis and correspondingly the associated resistance of the host was assayed. It was noticed that the biocontrol agent, Trichoderma significantly interacts with the pectolytic enzyme activity of the pathogen. It caused an appreciable reduction in enzymatic action. The reduction in the activity of polygalacturonase enzyme (PG) was recorded to be the highest among all the fractions of pectolytic enzymes. Such a trend appeared to be more pronounced in 'Kujja' than in 'Ghula' cultivar of jackfruit. The reduction in pectolytic enzyme activity was found to be coupled with a significant increase in the activity of polyphenol oxidase enzyme of the host tissues and a concomitant increase in host phenol content. Such inter-relationship between these two enzyme systems plays a key role to stimulate the defense mechanism of the host plant against infection. Significant increase in total phenol content of the host tissue during Trichoderma plant pathogen interaction that was recorded may correspond with the host defense response.
A radiochemical solvent extraction method for the determination of iron(III) employing the chelating extractant malonic anilide (MA), synthesized in our laboratory, has been described. Effects of different parameters on the extraction of iron(III) from 2M hydrochloric acid into a mixed organic solvent (methyl isobutyl ketone (TIBK) and diethyl ether) have been studied in detail. The method was applied for the estimation of iron content in several fruits using the principle of substoiciometric isotope dilution analysis.
A study on the seasonal incidence of the beetle
Champ and the relationship of various meteorological factors with its incidence in oyster mushroom (
Jacq. Ex Fr.) was conducted in the Department of Plant Pathology, Assam Agricultural University, Jorhat (India) during 1999–2000. Seasonal variation in the population density of adult beetles and per cent fruit body infestation by the adults and grubs were observed. Incidence of the beetle was recorded from March to November 1999 revealing the highest number (12.35) of adults per fruit body and per cent infestation (29.96) during July, 1999. The mushroom remained free from beetle incidence during the winter months. Beetle population per fruit body (10.43) and extent of infestation (26.03%) were higher during monsoon (June to August) where as the pre-monsoon period (March to May) recorded the beetle population and per cent infestation of 4.64 and 9.61%, respectively. Beetle population showed positive significant correlations with maximum (
< 0.05) and minimum temperature (
< 0.05) and number of rainy days (
< 0.01). Per cent fruit body infestation by the beetle exhibited positive significant correlations with maximum temperature (
< 0.05), minimum temperature (
< 0.05), total rainfall (
< 0.05) and number of rainy days
The work describes a procedure of preconcentration and separation of trace amounts of Pd(II) by solid phase extraction of
the metal ion by dithiooxamide groups incorporated into a matrix of polystyrene-divinylbenzene whereas the determination of
palladium has been carried out by radiotracer technique using 109Pd (T1/2 = 13.43 hr, Eγ = 311, 647 keV). The experiments were carried out using both batch method and column operation. Parameters such as the amount
of resin, effect of pH, equilibration rate, sorption and desorption of metal ions have been studied. The maximum sorption
capacity for palladium was found to be 0.10 mmol·g−1 at pH 6.0. The method is rapid, has a good accuracy and can be used routinely.