A review: Aeration efficiency of hydraulic structures in diffusing DO in water.

This paper contemplates the review of aeration efficiency with commonly used different aeration systems such as Venturi flumes, Weirs, Conduits, Stepped channels, In Venturi Aeration, the SAE value grows fast with the number of air holes. In Weir Aeration, it was found that among all the different labyrinth weir structure, triangular notch weirs are known for the optimum results for air entrainment. The ANN model was developed with parameters discharge (Q) and tail water depth (Tw) which showed that Q is more influential parameter than Tw. In conduits structure, it was found that circular high head gated conduits have better aeration performance than other conduits. Aeration efficiency in Stepped channels cascades may range from 30% to 70%. The sensitivity analysis with ANN model showed that discharge (Q) followed by number of steps (N) was the most influential parameter in E20. Bubble size was the important parameter to undertake when using bubble diffuser. The oxygen transfer efficiency (OTE) in jet diffusers was predicted developing an ANN model. It was found in sensitivity analysis that the input of 'velocity' is highly sensitive to OTE. According to literature, jets can provide OTE in the range of 1.91- 21.53kgO2/kW-hr.

Xanthine scaffold: scope and potential in drug development.

Medicinal plants have been the basis for discovery of various important marketed drugs. Xanthine is one such lead molecule. Xanthines in various forms (caffeine, theophylline, theobromine, etc) are abode in tea, coffee, cocoa, chocolate etc. giving them popular recognition. These compounds are best known for their diverse pharmaceutical applications as cyclic nucleotide phosphodiesterase inhibition, antagonization of adenosine receptor, anti-inflammatory, anti-microbial, anti-oxidant and anti-tumor activities. These properties incentivize to use xanthine as scaffold to develop new derivatives. Chemical synthesis contributes greater diversity in xanthine based derivatisation. With highlighting the existing challenges in chemical synthesis, the present review focuses the probable solution to fill existing lacuna. The review summarizes the available knowledge of xanthine based drugs development along with exploring new xanthine led chemical synthesis path for bringing diversification in xanthine based research. The main objective of this review is to explore the immense potential of xanthine as scaffold in drug development.

Effect of physicochemical parameters on enzymatic biodecaffeination during tea fermentation.

We report for the first time the development of a biodecaffeination process for tea synchronised with tea fermentation process using enzymes isolated from Pseudomonas alcaligenes. Cell-free extract was used for biodecaffeination of tea during fermentation of tea and 80% of the caffeine in the tea dhool was degraded within 90 min of incubation. Several factors that tend to effect the biodecaffeination during this stage, like moisture, aeration, intermittent enzyme addition and mixing, were optimized, and inhibitory interactions of proteins with polyphenols, caffeine-polyphenol interactions, which directly influence the biodecaffeination process were prevented by the use of glycine (5% w/w) in the dhool. Tea decaffeinated through the enzymatic route retained the original flavor and aroma, and there was an increase in the total polyphenol content of the tea.

Immobilised tyrosinase-based biosensor for the detection of tea polyphenols.

An amperometric principle-based biosensor containing immobilized enzyme tyrosinase has been used for detection of polyphenols in tea. The immobilized tyrosinase-based biosensor could detect tea polyphenols in the concentration range 10-80 mmol L(-1). Immobilization of the enzyme by the crosslinking method gave good stable response to tea polyphenols. The biosensor response reached the steady state within 5 min. The voltage response was found to have a direct linear relationship with the concentration of polyphenols in black tea samples. Enzyme membrane fouling was observed with number of analyses with a single immobilised enzyme membrane. The tyrosinase-based biosensor gave maximum response to tea polyphenols at 30 degrees C. The optimum pH was 7.0. This biosensor system can be applied for analysis of tea polyphenols. Variation in the biosensor response to black tea infusions gave an indication of the different amounts of theaflavins in the samples, which is an important parameter in evaluating tea quality. A comparative study of the quality attributes of a variety of commercially available brands of tea were performed using the biosensor and conventional analytical techniques such as spectrophotometry.

Production of plant growth regulators by some Fusarium species.

About 10 species of Fusarium were screened and tested for their growth regulatory activity on oat coleoptile straight growth test. Culture filtrates of four species contained growth-stimulating factors while others showed growth-inhibition responses on oat sections. On the whole, F. moniliforme was found to be produce higher stimulatory effects. Chromatographic analysis revealed the presence of several indole auxin and gibberellin-like plant-growth regulators in their culture filtrates. The quantity and biological activity of each indole spot was also measured.