Effect of gamma irradiation on the optical properties of CR-39 polymer

The UV-Visible absorption spectra of virgin and gamma irradiated (20–800 kGy) CR-39 polymer have been deduced by using Shimadzu Double beam Double Monochromator UV-Visible Spectrophotometer (UV-2550). The existence of the peaks, their shifting and broadening as a result of gamma irradiation has been discussed. Finally the indirect and direct band gap in virgin and gamma irradiated CR-39 has been determined. The values of indirect band gap have been found to be lower than the corresponding values of direct band gap.     

Serial cytological assay of micronucleus induction: a new tool to predict human cancer radiosensitivity

The role of the propeptide sequence and a disulfide bridge between sites 1 and 122 in chymotrypsin has been examined by comparing enzyme activities of wild-type and mutant enzymes. The kinetic constants of mutants devoid of the Cys1-Cys122 disulfide-linked propeptide show that this linkage is not important either for activity or substrate specificity. However this linkage appears to be the major factor in keeping the zymogen stable against non-specific activation. A comparison of zymogen stabilities showed that the trypsinogen propeptide is ten times more effective than the chymotrypsinogen propeptide in preventing non-specific zymogen activation during heterologous expression and secretion from yeast. This feature can also be transferred in trans to chymotrypsinogen; i.e. the chymotrypsin trypsin propeptide chimera forms a stable zymogen.     

Optimisation and comparative study on the addition of shrimp protein hydrolysate and shrimp powder on physicochemical properties of extruded snack

The effect of an addition of shrimp protein hydrolysate and shrimp powder on the physicochemical properties of extruded snack was studied. Rice flour and cornflour were used as base materials, and extrusion was done using corotating twin‐screw extruder. A mixture response surface methodology was used to study the effect of ingredient mixture on the physical, functional and sensory properties of extrudates. Linear and quadratic mixture response regression model was fitted to the response variables, and it was evaluated using R² values. Based on the desirability function score, the optimum combination of ingredient was 47.75% rice flour, 38.64% cornflour, 5.95% hydrolysate and 7.67% shrimp protein powder. It was observed that an addition of shrimp hydrolysate more than 5% (7.5%) improved the crispiness. Sensory evaluation revealed that shrimp hydrolysate and shrimp powder can be used at 5–7.5% level for developing protein‐rich extruded products without affecting sensory characteristics.     

Green Nanocomposites of Natural Rubber/ Olivine Nanosilica: Viscoelastic,Mechanical, Transport and Thermal Characterizations

Silicon - Nanosilica was synthesized from a low cost raw material, olivine by a more sustainable and cost effective method. The pure nanosilica obtained was amorphous in nature with a surface area...     

Transport of cobalt(II) through a hollow fiber supported liquid membrane containing di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the carrier

This work presents experimental, modeling and simulation studies for Co²⁺ ion extraction using hollow fiber supported liquid membrane (HFSLM) operated in a recycling mode. Extractant di-(2-ethylhexyl) phosphoric acid (D2EHPA) diluted with kerosene has been used as the membrane phase. The Co²⁺ ion concentration in the aqueous feed phase was varied in the range of 1–3 mM. Also, D2EHPA concentration was varied in the range of 10–30% (v/v). A mass transfer model has been developed considering the complexation and de-complexation reactions to be fast and at equilibrium. Equations for extractant mass balance and counter-ion (H⁺) transport have also been incorporated in the model. Extraction equilibrium constant (K_ex) for cobalt–D2EHPA system has been estimated from equilibration experiments and found to be 3.48 × 10⁻⁶. It was observed that the model results are in good agreement with the experimental data when diffusivity of metal-complex (D_m) through the membrane phase is 1.5 × 10⁻¹⁰ m²/s. Feed phase pH and strip phase acidity had negligible effect on the extraction profiles of Co²⁺ ions. An increase in D2EHPA concentration increased extraction rates of Co²⁺ ions. The membrane phase diffusion step was found to be the controlling resistance to mass transfer.     

Development and optimization of fish‐fortified instant noodles using response surface methodology

Proper and sensible formulation of ingredients in noodles facilitates its calorie cut down thus making it healthier. Fish being a source of cheap and quality protein can serve in the fortification of noodles. Hence, a study was done to formulate and develop fish noodles from Nemipterus japonicus. D‐optimal mixture experimental design with 15 runs was formulated to optimise the different levels of ingredients for noodles. Influence of different ingredients, viz. fish mince, wheat and refined wheat flour (maida) and potato starch, on the physical, cooking and sensory properties of fish noodles was evaluated. The protein content of noodles increased with increase in the fish mince incorporation. Water absorption capacity (WAC) was found to be directly related to the potato starch concentration. Positive correlation was observed between noodle protein content and cooking time. Desirability function scores revealed a noodle combination of 45% fish mince, 47% wheat: maida (1:1) mix and 8% potato starch as optimum.     

Geometry Dependence of Magnetization Reversal in Nanocomposite Alloys

The geometrical optimization of aligned hard-soft permanent-magnet nanocomposites is investigated by model calculations. Considered criteria are the shapes of the soft and c-axis-aligned hard phases, the packing fraction of the soft phase, and magnetostatic interactions. Taking into account that the energy product is enhanced via the volume fraction of the soft phase, subject to maintaining coercivity, we find that the best structures are soft-magnetic cubes as well as long rods with a square cross section. Comparing embedded soft cubes with embedded soft spheres of the same size, our nucleation-field analysis shows that the volume fraction of the soft phase is enhanced by 91%, with a coercivity reduction of only 25%. Magnetostatic interactions often but not always deteriorate the permanent-magnet performance, as exemplified by the example of MnBi:FeCo bilayers and multilayers.     

Exposure to enriched environment improves spatial learning performances and enhances cell density but not choline acetyltransferase activity in the hippocampus of ventral subicular-lesioned rats.

The authors demonstrated the efficacy of enriched housing conditions in promoting the behavioral recovery and neuronal survival following subicular lesion in rats. Chemical lesioning of the ventral subiculum impaired the spatial learning performances in rats. The lesion also induced a significant degree of neurodegeneration in the CA1 and CA3 areas of the hippocampus and entorhinal cortex. Exposure to enriched housing conditions improved the behavioral performance and partially attenuated the neurodegeneration in the hippocampus. The choline acetyl transferase (ChAT) activity in the hippocampus remained unchanged following ventral subicular lesion and also following exposure to an enriched environment. The study implicates the effectiveness of activity-dependent neuronal plasticity induced by environmental enrichment in adulthood following brain insult. (PsycINFO Database Record (c) 2010 APA, all rights reserved)