1,166 research outputs found
Probiotic effects of lactic acid bacteria against Vibrio alginolyticus in Penaeus (Fenneropenaeus) indicus (H. Milne Edwards)
Cell free extracts of four strains of Lactic acid bacteria (LAB) viz. Lactobacillus. acidophilus,
Streptococcus.cremoris, Lactobacillus bulgaricus –56 and Lactobacillus bulgaricus –57 inhibited
growth of Vibrio alginolyticus in nutrient broth. The antagonism of LAB to Vibrio
alginolyticus was further confirmed by streak plating wherein suppression of growth of Vibrio
was obtained.
Juveniles of Penaeus indicus (average weight 0.985 ± 0.1 g) on administering orally a
moist feed base containing 5 × 106 cells·g of the four LAB probionts for a period of four weeks
showed better survival (56 to 72%) when challenged with V. alginolyticus by intra-muscular
injection of 0.1 ml containing 3 × 109 cells·ml. Animals maintained on a diet devoid of bacterial
biomass exhibited 80% mortality
Fishing methods in coral reef areas of the Gulf of Mannar
Fishing methods being practised in the reef areas
of the Gulf of Mannar for finfishes are trawling,
gillnetting, fishing by hooks and lines and traps. Out of
these, the most important device is trawling by which
the most diverse and the highest quantity of finfishes
are being landed from coral reef areas in this region
Natural Rubber Based Fuel Rich Propellant for Ramjet Rocket
Development of fuel rich propellants for air-breathing propulsion is one of the frontier areas of research. This carries less oxidiser than the normal propellants, uses ram air for complete combustion and is heavily metallised. Studies were conducted at VSSC for the development of hydroxyl-terminated natural rubber (HTNR)-based Mg and Mg-Al alloy-filled polyurethane systems. The HTNR prepolymer was modified to make it free of acid functionality so as to avoid reaction with the metals and was then reacted with calculated amount of propylene oxide in the presence of tertiary amine catalyst at room temperature. Various levels of Mg and Mg-Al alloy were used in different compositions and the effect on propellant characteristics was studied. TMP and butane diol were used for higher crosslinking, chain extension, etc and their effects were evaluated. Propellant compositions using 30-35 per cent by weight of Mg/Mg-Al alloy with the modified prepolymer have been developed. They exhibit good processibility and mechanical properties. The feasibility of room temperature curing was attempted. Motors weighing 2 kg with 100 mm OD and 200 mm length were successfully static-tested in the primary mode for performance evaluation
Performance Evaluation and Experimental Studies on Metallised Gel Propellants
Metallised gel propellants offer higher specific impulse and volumetric loading, reduced vaporisation loss, spillage and slosh problems and easy storage in comparison to the conventional liquid propellants. Theoretical performance analysis of gel propellant containing Al in unsymmetrical dimethyl hydrazine-dinitrogen tetroxide (UDMH-N/sub 2/O/sub 4} system shows peak Isp (vacuum condition) of 316.7 s and 318.3 s at oxidiser/fuel (O/f) ratios of 1.5 and 1.0, respectively for 30 per cent and 40 per cent UDMH-Al gel propellants, under standard conditions. The effect of other parameters like area ratio and chamber pressure on performance has been brought out in view of mission oriented applications. Aluminium has been found to be a better choice over magnesium in metallised gel propellants. Experimental studies on UDMH gellation using propellant grade (15 micrometer)and pyrotechnic grade (1.5 micrometer)Al in 500g batch level show that gellant(methyl cellulose) concentration could be reduced by 50 percent using pyrotechnic grade Al. The pseudoplastic-thixotropic behaviour, flow rate through die holes, burst pressure tests and bulk density are studied. UDMH -25 to 30 per cent Al gels with both grades of Al are found to be stable, pseudoplastic (shear thinning) and thixotropic (time-dependent shear thinning), but their flow pattern through die holes differ in nature
Coral reef fishes of Gulf of Mannar, S.E of India
The coral reef ecosystem supports a wide variely of flora and fauna and Gulf of Mannar is one of its kind, located in the south-east of India. It comprises 21 islands along the 140 km stretch between Tuticorin and Rameswaram
Capillary Filling of Anodized Alumina Nanopore Arrays
The filling behavior of a room temperature solvent,
perfluoromethylcyclohexane, in approximately 20 nm nanoporous alumina membranes
was investigated in situ with small angle x-ray scattering. Adsorption in the
pores was controlled reversibly by varying the chemical potential between the
sample and a liquid reservoir via a thermal offset, T. The system
exhibited a pronounced hysteretic capillary filling transition as liquid was
condensed into the nanopores. These results are compared with Kelvin-Cohan
theory, with a modified Derjaguin approximation, as well as with predictions by
Cole and Saam.Comment: 4 pages, 3 figures, pre-proof
Studies on Composite Extrudable Propellant with varied Burning Rate Pressure Index 'n'
This paper discusses the development of composite propellantextrusion technique and the study of burning rate pressure indices nwith respect to compositional variations. The n is found to vary from0.35 to plateau and plateau to mesa by suitable compositionalmodifications. Compositional influence on burning rate with specificreference to plateau and mesaburning additives is described. Detailsof the process parameters like fluidity of the slurry, extrusion pressure,extrusion rate and die-swell are presented. This propellant is based onISRO-CTPB binder using ISRO-AP as oxidizer. Ammonium perchlorate (AP) particle size variation and inclusion of additives likePVC, lead stearate, ammonium sulphate, lithium fluoride etc. are foundto influence the burning rate pressure index n
Socio-economic assessment of major livelihood adaptations in Coral ecosystem
This paper outlines the importance of community based initiatives in managing the waste generated in the rural as well as urban areas of India. The study was carried out in Thiruvananthapuram district of Kerala to analyze how the lifestyle of people residing in a small village changed because of farming using the compost prepared from biodegradable waste generated in Kovalam rural tourism area. Fifty beneficiary farmers of the initiative were selected as respondents of the study. Results showed motivation and support of a non-government organization working in the locality as the major factor behind the waste management move. They created awareness about the need of composting to keep their surroundings clean and localization of chemical free food to stay healthy. It was observed that farmers adopted bio-pesticides and biodynamic preparations along with compost in their small home garden. The low cost farming not only provided chemical free food for the family and society but also improved the net income of the farmers' families. The effort taken by the promoting agency to popularize composting along with farming among the members of the society in the right time to a group of appropriate beneficiaries made the difference here
High prevalence of functional vitamin deficiencies in a psychogeriatric ward
Choline (Ch) is involved in relevant neurochemical processes. It is the precursor and metabolite of acetylcholine (ACh). It plays a role in single-carbon metabolism and is an essential component of different membrane phospholipids (PLs). These PLs are structural components of cell membranes, and involved in intraneuronal signal transduction. An increased ACh release was found after Ch treatment in rat corpus striatum slices. An in vivo proton magnetic resonance study has analyzed Ch ingestion effect. This work which represents the first non invasive study for exploring in vivo human brain neurochemistry showed the transfer of an oral Ch load in the brain of normal volunteers. These results were not confirmed by other in vivo studies. Cellular membranes breakdown is suggested as a feature of neurodegeneration in acute (stroke) and chronic (Alzheimer’s and vascular dementias) brain disorders. The effects of exogenous CCPLs on different brain areas were largely studied. Our group has assessed the influence of treatment with the CCPL, choline alphoscerate (GPC) on brain cholinergic neurotransmission markers in an animal model of brain vascular injury. A neuroprotective effect of GPC alone or in association with acetylcholinesterase inhibitor, galantamine was found. These results suggest that GPC could stimulate the expression of vesicular ACh transporter and Ch transporter primarily in areas involved in cognitive processes. These cholinergic markers could represent an appropriate mean to investigate brain cholinergic pathways. In the lack of novel therapeutic strategies, safe compounds developed since a long time such as the CCPLs could have still a place in pharmacotherapy and would merit to be investigated by new clinical studies
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