Some aspects of reproductive biology of two sciaenids, Otolithes cuvieri Trewavas and Johnius elongatus Mohan: maturation, spawning, sex ratio and fecundity

The gonads of Otolithes cuvieri and Johnius elongatus are described in seven maturity stages. O. Cuvieri spawns once a year from April to September as evidence by ova diameter frequency distribution and GSI values. 50% maturity is attained at 210mm TL in males and 200mm TL in females. Fecundity ranged from 2387 to 104379 with a mean value of 33502. Log-Log relationship between fecundity and total lenght, body weight and ovary weight were determined. An overall sex ratio of 1.54:1.00 was unequal in favour of males. Johnius elongatus spawns twice a year from January-February to Aprile-May and from August to October as evidence by ova diameter frequency distribution and GSI values. 50% maturity is attained at 140-143mm TL in both sexes. Fecundity ranged from 4238 to 167669 with a mean value of 42818. Log-Log relationship between fecundity and total lenght, body weign and ovary weight were determined. An overall sex ratio of 1.00:1.20 was unequal in favour of females

Statistical Optimization of Oxidative Derivatization of Polyethylene Glycol to Polyethylene Carboxylate Using Custom Design Approach

Reaction optimization has been a tedious task for the research chemist for very long and many approaches has been employed to achieve the best reaction condition resulting in highest yield. As an answer to this problem the statistical optimization approach has better chances of providing most acceptable solution to it. Through, our present work we have found that among other statistical approaches the custom design approach is the best methodology to be adopted for optimizing any synthetic reaction. The oxidative transformation of polyethylene glycol into polyethylene carboxylate by the use of TEMPO, NaClO and KBr; has been optimized by identifying the key factors affecting the yield and exact ratios of them to achieve highest possible yield. Here, we have employed custom design approach to further limit the experimental runs and yet find a better possible combination of reagents and conditions to get highest yield with maximum purity. This method has reduced the number of runs to only 16, which was 1024 in case of the traditional OVAT approach and in full factorial approach it was 64 runs. Thus, custom design method of DoE has been satisfactorily utilized for optimizing the oxidative derivatization of polyethylene glycol to polyethylene carboxylate