The free alpha amino acid nitrogen contents of some common food fishes of Kakinada region, Andhra Pradesh

The moisture and free alpha amino nitrogen contents of some important food fishes and shell fishes of Kakinada region have been studied. Crustaceans and molluscs contain free alpha amino acids in quantities several times higher than all other aquatic animals examined in this study. Their probable role in the physiological activities of these animals has been discussed.

Advantages of liquid nitrogen freezing of Penaeus monodon over conventional plate freezing

Liquid nitrogen frozen products are biochemically and organoleptically superior to conventional plate frozen products but beneficial effect of liquid nitrogen freezing over conventional plate freezing can exist only up to 59 days at a commercial storage temperature of -18°C.

Nitrogen fixing bacteria, Azotobacter sp. in aquatic sediment

Non-symbiotic, free living, nitrogen fixing bacteria, Azotobacter sp. was estimated in sediments of estuarine, marine, backwater and mangrove environments of Portonovo. Number of colony forming units (CFU) of Azotobacter sp. was less (5 to 27 cells/g of dry sediment). CFU of total heterotrophic bacteria (THB), actinomycetes and fungi were between 4.1x10 super(6) and 4.5x10 super (7), 0.8x10 super(5) and 4.9x10 super(5), 1.1x10 super(5) and 3.8x10 super(5)/g respectively. Mangrove sediments contained more CFU of the above microbial groups.

Effect of liquid nitrogen freezing and subsequent storage on survival of Staphylococcus aureus and Streptococcus pyogenes in treated prawn meat

Prawn meat treated with Streptococcus pyogenes B-49-2 culture and Staphylococcus aureus ATCC-12598 culture were frozen in conventional plate freezer at -40°C and by spray type liquid nitrogen freezer. The frozen products were stored at -18°C. Streptococcus pyogenes B-49-2 showed low sensitivity to cold injury during freezing and frozen storage. Staphylococcus aureus ATCC-12598 survived during the entire storage period of 240 days. Total bacterial count of untreated prawn meat was found to be always lesser in liquid nitrogen frozen products than that in plate frozen products.

Influences of dietary lipid and phosphorus levels on retention and excretion of phosphorus and nitrogen in fingerlings red sea bream, Pagrus major

A laboratory based 2x3 factorial experiment was conducted for 12 weeks to investigate the influences of dietary lipid and phosphorus (P) levels on retention and excretion of phosphorus and nitrogen (N) in fingerling red sea bream. Two levels of lipid (210 and 260 g/kg) and three levels of phosphorus (17, 14 and 12 g/kgˉ¹) in the dry diets were tested. Duplicate groups of 25 red sea bream (average weight 3.74±0.07 g) per 60L glass tank were fed experimental diets three times a day near to satiation level at 22 to 28°C water temperature. A reduction in dietary fish meal from 500 to 300 g/kg dry diet, corresponding to a supplementation in both dietary lipid and P resulted in significant increase in both P and N retention which resulted in the reduction of their excretion by red sea bream. The overall results of the present study demonstrated that both lipid and phosphorus supplementation are necessary for developing less-polluting feed which in turn, reduce fish meal level in the diet of fingerling red sea bream. Further studies in this regard with different size and age groups of red sea bream are warranted.

Glycine uptake regulates hippocampal network activity via glycine receptor-mediated tonic inhibition

Functional glycine receptors (GlyRs) are enriched in the hippocampus, but their role in hippocampal function remains unclear. Since the concentration of ambient glycine is determined by the presence of powerful glycine transporter (GlyT), we blocked the r

An investigation of the kinetics of CO2 uptake by a synthetic calcium based sorbent

This study examines the kinetics of carbonation by CO2 at temperatures of ca. 750 °C of a synthetic sorbent composed of 15 wt% mayenite (Ca12Al14O33) and CaO, designated HA-85-850, and draws comparisons with the carbonation of a calcined limestone. In-situ XRD has verified the inertness of mayenite, which neither interacts with the active CaO nor does it significantly alter the CaO carbonation–calcination equilibrium. An overlapping grain model was developed to predict the rate and extent of carbonation of HA-85-850 and limestone. In the model, the initial microstructure of the sorbent was defined by a discretised grain size distribution, assuming spherical grains. The initial input to the model – the size distribution of grains – was a fitted parameter, which was in good agreement with measurements made with mercury porosimetry and by the analysis of SEM images of sectioned particles. It was found that the randomly overlapping spherical grain assumption offered great simplicity to the model, despite its approximation to the actual porous structure within a particle. The model was able to predict the performance of the materials well and, particularly, was able to account for changes in rate and extent of reaction as the structure evolved after various numbers of cycles of calcination and carbonation.

An investigation of the kinetics of CO 2 uptake by a synthetic calcium based sorbent

This study examines the kinetics of carbonation by CO 2 at temperatures of ca. 750°C of a synthetic sorbent composed of 15wt% mayenite (Ca 12Al 14O 33) and CaO, designated HA-85-850, and draws comparisons with the carbonation of a calcined limestone. In-situ XRD has verified the inertness of mayenite, which neither interacts with the active CaO nor does it significantly alter the CaO carbonation-calcination equilibrium. An overlapping grain model was developed to predict the rate and extent of carbonation of HA-85-850 and limestone. In the model, the initial microstructure of the sorbent was defined by a discretised grain size distribution, assuming spherical grains. The initial input to the model - the size distribution of grains - was a fitted parameter, which was in good agreement with measurements made with mercury porosimetry and by the analysis of SEM images of sectioned particles. It was found that the randomly overlapping spherical grain assumption offered great simplicity to the model, despite its approximation to the actual porous structure within a particle. The model was able to predict the performance of the materials well and, particularly, was able to account for changes in rate and extent of reaction as the structure evolved after various numbers of cycles of calcination and carbonation. © 2011 Elsevier Ltd.

Spectroscopic characterization of protein-wrapped single-wall carbon nanotubes and quantification of their cellular uptake in multiple cell generations

We study the spectral characteristics of bovine serum albumin (BSA) protein conjugated single-wall carbon nanotubes (SWNTs), and quantify their uptake by macrophages. The binding of BSA onto the SWNT surface is found to change the protein structure and to increase the doping of the nanotubes. The G-band Raman intensity follows a well-defined power law for SWNT concentrations of up to 33 μg ml-1 in aqueous solutions. Subsequently, in vitro experiments demonstrate that incubation of BSA-SWNT complexes with macrophages affects neither the cellular growth nor the cellular viability over multiple cell generations. Using wide spot Raman spectroscopy as a fast, non-destructive method for statistical quantification, we observe that macrophages effectively uptake BSA-SWNT complexes, with the average number of nanotubes internalized per cell remaining relatively constant over consecutive cell generations. The number of internalized SWNTs is found to be ∼30 × 106 SWNTs/cell for a 60 mm-2 seeding density and ∼100 × 10 6 SWNTs/cell for a 200 mm-2 seeding density. Our results show that BSA-functionalized SWNTs are an efficient molecular transport system with low cytotoxicity maintained over multiple cell generations. © 2013 IOP Publishing Ltd.

Water, salt water, and alkaline solution uptake in epoxy thin films

As a means of characterizing the diffusion parameters of fiber reinforced polymer (FRP) composites within a relatively short time frame, the potential use of short term tests on epoxy films to predict the long-term behavior is investigated. Reference is made to the literature to assess the effectiveness of Fickian and anomalous diffusion models to describe solution uptake in epoxies. The influence of differing exposure conditions on the diffusion in epoxies, in particular the effect of solution type and temperature, are explored. Experimental results, where the solution uptake in desiccated (D) or undesiccated (U) thin films of a commercially available epoxy matrix subjected to water (W), salt water (SW), or alkali concrete pore solution (CPS) at either 20 or 60°C, are also presented. It was found that the type of solution did not significantly influence the diffusion behavior at 20°C and that the mass uptake profile was anomalous. Exposure to 60°C accelerated the initial diffusion behavior and appeared to raise the level of saturation. In spite of the accelerated approach, conclusive values of uptake at saturation remained elusive even at an exposure period of 5 years. This finding questions the viability of using short-term thin film results to predict the long-term mechanical performance of FRP materials. © 2013 Wiley Periodicals, Inc.