Design and evaluation of sustained release matrix tablets of levofloxacin for effective treatment of microbial infections

The objective of present work was to formulate and evaluate sustained release matrix tablets of levofloxacin for treating microbial infections effectively. Levofloxacin is the active component of the racemate ofloxacin, and used for treating a variety of clinical conditions such as lower respiratory tract infections, acute sinusitis, uncomplicated skin and soft-tissue infections and complicated urinary tract infections. Different formulations were prepared by wet granulation method using various release rate controlling hydrophilic polymers. The formulations were evaluated for hardness, weight variation, friability and drug content uniformity. The in vitro release of drug from the formulations was studied in pH 1.2 acidic buffer and pH 6.8 phosphate buffer, and it was found that the prepared tablets were able to sustain the release of the drug. The release of levofloxacin from the tablets was diffusion controlled and the release mechanism was non-Fickian. For conclusion, the developed formulations may reduce the dosing intervals, reduce the dose related side effects and increase the drug’s efficacy for treating infections.Keywords: Matrix tablets, levofloxacin, HPMC, guar gum, xantham gum, locust bean gum, Amorphophallus starch

Radiating dipoles in photonic crystals

The radiation dynamics of a dipole antenna embedded in a Photonic Crystal are modeled by an initially excited harmonic oscillator coupled to a non--Markovian bath of harmonic oscillators representing the colored electromagnetic vacuum within the crystal. Realistic coupling constants based on the natural modes of the Photonic Crystal, i.e., Bloch waves and their associated dispersion relation, are derived. For simple model systems, well-known results such as decay times and emission spectra are reproduced. This approach enables direct incorporation of realistic band structure computations into studies of radiative emission from atoms and molecules within photonic crystals. We therefore provide a predictive and interpretative tool for experiments in both the microwave and optical regimes.Comment: Phys. Rev. E, accepte

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Not AvailableCassava is one of the most important tropical tuber crops that ensure food and nutritional security in the developing countries. In India, cassava is cultivated mainly in the southern states viz., Tamil Nadu, Kerala and Andhra Pradesh. Harvesting is one of the major difficult and labour intensive operations in cassava cultivation. In India, cassava is mostly harvested manually by hand. This study was attempted to evaluate the performance of tractor operated Tamil Nadu Agricultural University (TNAU) cassava harvester with two industrial varieties (H-165 and Mulluvadi) and two commercial planting system (Mound and Ridge) using six treatments in a randomized complete block design (RCBD). Based on the field performance trial, the shank length and width of digging blade were modified and then their dimensions were optimized for better performance. Among the selected treatments, it was found that a minimum damage of 4.12% was observed for H-165 variety under manual harvesting and a maximum damage of 9.05% for Mulluvadi variety in mound planting system under mechanized harvesting was noticed. The tuber spread length was highly correlated with the per centage damage (%) of cassava tubers. Thus, the tuber spread length is an important agronomical parameter to be considered while selecting the variety for mechanization of cassava harvesting. This study also confirmed that the ridge planting system is highly suitable for operating mechanized harvester as compared to mound planting system.Not Availabl

Comparison of ethanol yield from pretreated lignocellulo-starch biomass under fed-batch SHF or SSF modes

The ethanol yields from lignocellulo-starch biomass (peels of sweet potato, elephant foot yam, tannia, greater yam and beet root) by fed-batch separate hydrolysis and fermentation (F-SHF) and simultaneous saccharification and fermentation (F-SSF) using Saccharomyces cerevisiae were compared. Fed-batch saccharification of steam or dilute sulphuric acid pretreated biomass enhanced the reducing sugar yield which resulted in high RS consumption, volumetric ethanol productivity and ethanol yield during the first 24 h fermentation under F-SHF mode, while continuous production and utilization of reducing sugars occurred up to 72 h in F-SSF. Dilute sulphuric acid pretreated residues under F-SHF gave higher ethanol yield (34–43 g/L) and productivity (274–346 ml/kg dry biomass) than steam pretreatment (27–36 g/L and 223–295 ml/kg respectively), while F-SSF was superior for steam pretreated peels of sweet potato, elephant foot yam and tannia giving ethanol yields from 281 to 302 ml/kg. Glucose and xylose were present in all the hydrolysates with a preponderance of glucose and fermentation resulted in significant reduction in glucose levels in both F-SHF and F-SSF. Higher levels of total soluble phenolics and hydroxymethyl furfural were observed in the hydrolysates from dilute sulphuric acid pretreatment and yeast assimilated/detoxified part of the inhibitors, while only trivial amounts of furfural were present due to the low xylose content in the hydrolysates. Continuous formation led to higher accumulation of inhibitors in F-SSF despite supplementation with the detoxification mix comprising Tween 20, polyethylene glycol and sodium borohydride. F-SHF of dilute sulphuric acid pretreated biomass could be considered as a comparatively advantageous process where only one time feeding of enzyme cocktail and yeast was adopted compared to multiple feeds of enzymes and yeast along with other additives such as detoxification mix or nutrient solution in F-SSF

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Chromatic exclusivity hypothesis and the physical basis of floral color

International audienceThis paper presents the results of floral spectral studies on 1275 flowers from India, Brazil, Israel, Germany, and Norway. Floral spectral reflectance from 400 to 700 nm (nm) was used to quantitatively represent ‘human-perceived’ color of flowers in Red, Green, Blue color space. Floral spectral reflectance from 350 to 600 nm was used to discern and objectively represent ‘insect pollinator-perceived’ flower colors in color hexagon. We leverage the advantage offered by ‘quantified human perception’ provided by ‘human-perceived’ floral colors to represent the distribution of floral hues and uncover the relationship between the composition of incoming solar radiation and predominant ‘human-perceived’ floral colors at the tropics and the higher latitudes. Further, the observed species-level mutual exclusivity of ‘insect pollinator-perceived’ floral colors is stated as chromatic exclusivity hypothesis. We compare ‘human-perceived’ and ‘insect pollinator-perceived’ floral colors at Trivandrum (India) and provide a physical explanation for short and long ‘wavelength triads’ of insect pollinator and human visual sensitivity respectively