The Influence of high pressure on the bending rigidity of model membranes

Curvature is a fundamental lipid membrane property that influences many membrane-mediated biological processes and dynamic soft materials. One of the key parameters that determines the energetics of curvature change is the membrane bending rigidity. Understanding the intrinsic effect of pressure on membrane bending is critical to understanding the adaptation and structural behavior of biomembranes in deep-sea organisms as well as soft material processing. However, it has not previously been possible to measure the influence of high hydrostatic pressure on membrane bending energetics, and this bottleneck has primarily been due to a lack of technology platforms for performing such measurements. We have developed a new high-pressure microscopy cell which, combined with vesicle fluctuation analysis, has allowed us to make the first measurements of membrane bending rigidity as a function of pressure. Our results show a significant increase in bending rigidity at pressures up to 40 MPa. Above 40 MPa, the membrane mechanics become more complex. Corresponding small and wide-angle X-ray diffraction shows an increase in density and thickness of the bilayer with increasing pressure which correlates with the micromechanical measurements. These results are consistent with recent theoretical predictions of the bending rigidity as a function of hydrocarbon chain density. This technology has the potential to transform our quantitative understanding of the role of pressure in soft material processing, the structural behavior of biomembranes, and the adaptation mechanisms employed by deep-sea organisms

Modeling of call - by - need and stream primitives using CCS

technical reportThe semantics of an applicative language are presented using the algebraic primitives introduced in CCS. In particular, the language constructs modeled allow for nondeterminism, stream processing and demand driven (call by need) evaluation

An algebraic formulation of seitz's weak conditions for self timed circuits

technical reportTwo fairly intuitive conditions are given that serve to algebraically characterize Seitz's "weak conditions" for self timed circuits. It is shown that these two conditions embody the 12 temporal logic conditions (developed b y Owicki and Malachi) which are intended to express both the weak conditions as well as certain liveness properties that self timed circuits need to satisfy

Miscellany: benefits of forests, direct and indirect

Forests are known to provide a wide range of benefits including provisioning, regulatory, cultural and supporting services.They provide food, fodder, fuelwood, timber, manure, and medicinal products. Forests also absorb rain water and release it slowly, allowing seepage into the soil, preventing its run-off with water

sessment of ground water contamination in Erode District, Tamilnadu

A systematic study has been carried out to assess the water contamination and the effect of the tanneries and dyeing industries effluents on Erode District, Tamil Nadu. Ten (10) sampling locations were selected in and around industries. The water samples were collected from the selected sampling points. The samples were analyzed for major chemical water quality parameters like pH, EC, Ca, Mg, Cl, SO4, Na, CO3 and HCO3. The present investigation shows a constant variation in different parameters in different locations. So it is highly important to take periodical monitoring of the ground water quality in this region for future sustainability.Key words: Erode district, Tamilnadu, contamination assessment, tanneries and dyeing industries

Occurrence of Phosphate-Solubilizing Bacteria in Rhizospheric and Pneumatophoric Sediment of Avicennia marina

The present study deals with the isolation and characterization of phosphorus-solubilizing bacteria (PSB) from Avicennia marina rhizospheric sediment, pneumatophoric sediment and non-rhizospheric sediment. The sampling was carried out in four mangrove forests of Mumbai, India. The physicochemical parameters like pH, electrical conductivity, organic carbon, texture, total Phosphorus (P), inorganic P, organic P, Olsen P, iron, calcium, magnesium and zinc in sediment were analysed along with the isolation and molecular characterization of PSB. Significantly, lower pH was observed in the rhizospheric sediment than in the pneumatophoric and bulk sediment. Abundance of PSB was also found in the rhizospheric zone. This was supported by other physicochemical parameters such as high organic P, Olsen P, and higher bacterial count along with low inorganic P. In this study, 8 PSB were isolated and 16S rDNA sequence revealed that all the isolates belong to the genus Bacillus. Among the PSB isolates, B. subtilis sub. spizizenii TU-B-10 showed significantly higher solubilization activity (85.8±0.0 µg P released per 108 cfu in 72 hrs). The isolates that showed higher phosphate-solubilizing potentials can be explored as phosphatic bio-fertilizer to enhance the agricultural, aquacultural and mangrove productivity

Growth performance of Spirulina (Arthrospira) platensis in a low cost medium: An assessment

The unialgal culture of Spirulina platensis was sub-cultured in Zarrouk’s medium under photoautotrophic conditions. Initially, indoor batch cultivation was carried out for a week in four different types of cultivation media viz., Zarrouk’s, Modified Zarrouk’s, prescribed Nallayam Research Centre (NRC), and Modified NRC. In modified medium, urea and phosphoric acid of NRC medium were replaced with sodium nitrate and dipotassium hydrogen phosphate (anhydrous) and concentration of ferrous sulphate heptahydrate was reduced. The batch and airlift indoor culture experiments were carried out with an illumination of 3500±100 lux, photoperiod of 12:12 hour light and dark periods and temperature of 24±1°C. The specific growth rate value was 5.7 % higher in Zarrouk’s medium as compared to modified NRC medium. However, the cost of modified NRC medium was considerably lower than Zarrouk’s medium; therefore, modified NRC medium was selected for outdoor studies. The outdoor mass cultivation was done under natural conditions with the solar radiation reaching the surface of culture was between 2160 and 8450 lux and temperature ranged from 27 to 34°C. An assessment of the performance of growth in batch, airlift and FRP (Fiber Reinforced Polymer) tanks revealed that culture grown in airlift units showed best growth which was evident from higher specific growth rate and number of doublings per day. There was a 3.4-fold increase in cell density (in terms of turbidity at 750 nm) of the cultures in such units. The growth in outdoor FRP tanks was also comparable to the airlift cultures

Animal hygiene and sustainable livestock production: impact of ground water contamination with arsenic

There is a growing concern all over the world about contamination of ground water with Arsenic. One of the major repercussions of arsenic contamination is degradation of animal hygiene that ultimately affects sustainable livestock production. The reports suggest that concentration of Arsenic in ground water of twenty one countries is well above the guideline values. Use of such contaminated water for animal husbandry and livestock production compromises with the hygienic value of animal products. Therefore, there is an urgent need to develop low cost treatment technologies for reducing the level of arsenic in ground water to maintain the hygiene and sustainability of livestock production. Most of the traditional treatment technologies are costly and less effective in reducing arsenic concentration to safer limits. Therefore, during present study, an attempt was made to design a low-cost algal adsorbent based filtration unit consisting of polyurethane columns with entrapped algal adsorbents. The column was made of adsorbents of algal origin like agar-agar, alginic acid, calcium alginate and Spirulina platensis biomass entrapped in polyurethane foam matrix. The performance of the column was assessed in terms of removal efficiency and the quantity of metal sequestered in unit time interval. The results from the study the show that algal biosorbents and S. platensis biomass combination has a capacity to adsorbed arsenic from aqueous solution. The simple design, easy fabrication and no energy requirement for the operation of the filtration unit developed under the present study is suitable to rural areas where arsenic contamination of ground water is adversely affecting the animal hygiene and sustained livestock production

Paratuberculosis in different breeds of sheep: A retrospective study of cases

AbstractSpontaneous ovine paratuberculosis in an organized farm was diagnosed based on histopathological lesions, demonstration of acid-fast bacilli in different visceral organs, and detection of antibody levels against Mycobacterium paratuberculosis by agar gel immunodiffusion test (AGID). Out of 190 morbid specimens examined histopathologically, 77% of specimens had pathological lesions, which included predominant epithelioid cell formation, infiltration of lymphocytes, monocytes and macrophages. In acid-fast staining of tissue sections, 74% of intestinal specimens and 53% of mesenteric lymph nodes were positive for the presence of acid-fast bacilli. Hematologically, the animals were showing leucopenia, macrocytic and normochromic anemia. Out of 49 animals tested, 28.5% of animals were positive for antibodies against M. paratuberculosis. Local breeds, namely Nilagiri and Sandyno sheep, were found to be more susceptible than exotic breeds, namely Dorset. Females were more susceptible than males. Mortality was noticed in the age group of 4months to 10years