Modelling of calcium leaching and its influence on radionuclide migration across the concrete engineered barrier in a NSDF.

A multi barrier concept of disposal is adopted for both low and intermediate level radioactive waste disposal to prevent the spread of radionuclides into the human environment. Concrete engineered barrier is a part of multi barrier system for radioactive waste disposal. As long as the concrete barrier is intact, the containment of radioactive waste within the disposal facility is assured. However, every concrete structure has a finite lifetime. Concrete barriers degrade with time with lifetime dependent on type of concrete, external and internal environmental factors. This degradation allows the free moment of the radionuclides out of the concrete barrier. Hence an attempt was made to model the Calcium (Ca) leaching from side wall of a concrete engineered barrier in a Near Surface Disposal Facility (NSDF) and its influence on radionuclide migration across the concrete barrier, limited to conditions specified in the paper. The conceptual model assumes that rain water seeps into the engineered barrier through the top cover and dissolves radionuclides from the nuclear waste matrix. The modelling was attempted with Finite Difference analysis and validated with the results available in literature. The influence of Ca leaching on radionuclide migration in concrete barrier has been discussed for eight different radionuclides (Cs-137, Sr-90, I-129, H-3, Pu-239, Am-241, Co-60 and Tc-99).

Effect of magnetic field on the biosynthesis of neomycin by Streptomyces marinensis.

The effect of 30, 70, 90, 100, 110 and 150 gauss permanent magnetic field strength on the growth and neomycin titre of Streptomyces marinensis was studied. Maximum growth was attained in 120 h at all magnetic strengths. Gradual increase in neomycin titre was observed with increase of magnetic field strength up to 110 gauss.

Strain improvement studies for cephalosporin C production by Cephalosporium acremonium.

Treatment of spore suspension of Cephalosporium acremonium ATCC 48272 with UV rays and N-methyl-N-nitro-N-nitrosoguanidine (NTG) induced mutants capable of producing higher yields of cephalosporin C. Antibiotic yield was improved from 630 micrograms/ml to 1995 micrograms/ml of the broth resulting in a high yielding mutant.

Production and optimization studies of cephalosporin C by solid state fermentation.

Production of cephalosporin C employing a strain, Cephalosporium sp. NCIM 1039 under solid state fermentation was optimized. Different substrates like wheat bran, wheat grains, rice grains, barley and rice bran were studied to optimize the best substrate. Wheat bran showed the highest antibiotic yield. The physical and chemical parameters were optimized. The maximum productivity of cephalosporin C (750 U/g) was achieved by employing wheat bran and with optimized nutritional and process parameters such as potato starch as additive 1% w/w, urea as additive 1% w/w, incubation period of 7 days, incubation temperature at 30 degrees C, inoculum level 10% w/v, moisture content of solid substrate 80% and pH 7.0.

Bioactive rare actinomycetes from indigenous natural substrates of Andhra Pradesh.

This investigation reports the occurrence of bioactive rare actinomycetes from different indigenous natural substrates of Andhra Pradesh. During the course of our investigation on 20 terrestrial soil samples, 5 marine samples and 3 fresh water samples, a total of 92 rare actinomycetes belonging to Micromonospora, Nocardia, Actinomadura and Thermoactinomyces genera were isolated. The antimicrobial and enzymatic activities were studied for all the isolates. The antibacterial and antifungal activities were studied preliminarily by cross-streak method followed by submerged fermentation studies employing standard cup-plate method for the assay. It was found that 34 isolates (36.95%) showed excellent antibacterial activity and 29 isolates (31.52%) showed good antifungal activity. Proteolytic and amylolytic activities were also studied. It was observed that 79 isolates (85.86%) showed proteolytic activity and 75 isolates (81.52%) showed amylolytic activity.

Bioactive actinomycetes from Krishna River sediments of Andhra Pradesh.

Sediment samples from Krishna River at Nagayalanka of Andhra Pradesh, India were investigated as a source of actinomycetes to screen for the production of novel bioactive compounds. During our investigation on fresh water actinomycetes from 5 different river sediment samples, a total of 80 actinomycetes were isolated. Out of these 80 isolates, 30 isolates which showed distinct macromorphological characteristics were selected. The antimicrobial and enzymatic activities were studied for all the 30 isolates. The preliminary study for antimicrobial activity by cross streak method indicated that 16 isolates (53.3%) have excellent antagonistic properties. All these 16 isolates were subjected to detailed submerged fermentation studies. It was observed that 12 isolates (40.0%) exhibited antibacterial activity, 9 isolates (30.0%) showed antifungal activity while 5 isolates (16.6%) showed both antibacterial and antifungal activities. All the 30 isolates were also subjected for the determination of enzymatic activities 25 isolates (83.3%) exhibited amylolytic activity while 27 isolates (90.0%) showed proteolytic activity. Among these isolates, six promising isolates were selected for detailed morphological, cultural, physiological and biochemical studies. It was established that these isolates belong to the Streptomyces genus by virtue of their cell wall composition pattern and were identified as strains of different Streptomyces species like S. rochei, S. alanosinicus, S. erumpens, S. griseoplanus, S. gancidicus and S. nigrogriseolus.

Response surface optimization of the critical medium components for the production of alkaline protease by a newly isolated Bacillus sp.

PURPOSE: Optimization of the fermentation medium for maximum alkaline protease production was carried out using a new strain, Bacillus Sp. PE-11. METHODS: The carbon source (glucose), the nitrogen source (peptone) and salt solution were selected to optimize. A 2(3 )full factorial composite experimental design and response surface methodology were used in the design of experiments and in the analysis of results. This procedure limited the number of actual experiments performed while allowing for possible interactions between the three components. RESULTS AND DISCUSSION: The optimum values for the tested variables for the maximum alkaline protease production were; glucose 7.798 (g/L), peptone 9.548 (g/L) and salt solution 8.757%. The maximum alkaline protease production was 4,98,123 PU/L. This method was efficient; only 20 experiments were necessary to assess these conditions, and model adequacy was very satisfactory, as the coefficient of determination was 0.941. CONCLUSIONS: In the work, we have demonstrated the use of a central composite factorial design by determining the conditions leading to the high yield of enzyme production. Thus, smaller and less time consuming experimental designs could generally suffice for the optimization of many fermentation processes.

Use of body mass index for assessing the growth status of infants.

Growth status of infants measured by weight and height was assessed from birth to 12 months in a randomly selected community from the urban slums of Hyderabad City. Mean birth weight was 2.82 kg. Weight/height indicator of body mass index (BMI) showed a progressive increase till 4th month, followed by more or less a constant figure with a mean value of 1.50 in longitudinal, semi-longitudinal and cross sectional data till one year. Critical limit for BMI at birth for given weight of 2.5 kg was 1.20 and subsequently increased to 1.35. BMI was well correlated with weight and weight for height (%) and least correlated with height. Children with height of 90% or above and birth weight of above 2.5 kg were observed with better growth and better maintenance of weight for height (%) and BMI till 6 months.