Effect of Temperature Variations on Vermicomposting of Household Solid Waste and Fecundity of Eisenia fetida

Experiments were conducted in winter (October to January) and summer (May to August) seasons to study the effect of seasonal temperature variations on the vermicomposting of household waste using Eisenia fetida earthworms. The prevailing temperatures during experiments were in the range of ?2.7°C to 35.0°C during winter season and 18.0°C to 44.4°C during summer season. Organic matter degradation was higher during winter than summer season. The electrical conductivity (EC) of vermicomposts was increased in the range of 2.3–7.8% in winter season; however, the increase in EC was 0.9–1.8% during summer season for different waste mixtures. There was about 56.2–80% increase in total Kjeldahl nitrogen (TKN) content during winter season, whereas the TKN increase was 23.9–44% during summers. The C:N ratio also decreased remarkably in all the waste mixtures during vermicomposting in both the seasons. However, the C:N ratio reduction was more significant during winter (47–60%) than in summer (31–44%). After the observation period, the net worm biomass achieved was higher during winter than summer season. The temperature variations during winter supported the life activities of earthworms more favourably than in summer. The results indicated that growth and reproductive potential of the earthworms were affected not only by the quality and quantity of the feed but also by ambient temperature.     

Use of dietary diversity score as a proxy indicator of nutrient adequacy of rural elderly people in Sri Lanka

ABSTRACT: BACKGROUND: Macro and micro nutrient deficiencies are public health concerns in most developing countries including Sri Lanka, partly due to monotonous, cereal-based diet that lacks diversity. The objective of the study was to assess validity of food variety score (FVS), dietary diversity score (DDS) and dietary serving score (DSS) as indicators of nutrient adequacy of rural elderly people in Sri Lanka. FINDINGS: A sample of 200 apparently healthy elderly people >60y of age were studied. A single 24 h recall was performed to compute dietary diversity indicators. Pearson's correlation was used to assess the utility of FVS, DDS and DSS as indicators of nutrient adequacy. Sensitivity (Se) and specificity (Spe) analysis were done to determine the most appropriate cut-off points for using FVS and DDS to categorize elderly people with adequate nutrient intake. The average (standard deviation) of the food variety score, dietary diversity score and dietary serving score was 8.4 (2), 4.4 (0.9) and 11.4 (2.5), respectively. Mean adequacy ratio (MAR) of 12 nutrients was 0.39 (39 %). Pearson's correlation coefficients between MAR and FVS was 0.45 (P < 0.01), for DDS it was 0.48 (P < 0.01) and for DSS it was 0.58 (P < 0.01). When maximizing sensitivity and specificity, the best cut-off point for achieving 50 % of MAR was about 9 and 4.5 for FVS and DDS, respectively. CONCLUSION: In conclusion, FVS, DDS and DSS were useful proxy indicators of nutrient adequacy of rural elderly people in Sri Lanka. Indeed, the performance of the indicators is improved when considering the quantities of food consumed.     

Experiments with a turing gas: Mimicking chemical evolution

Three different experiments with colliding artificial molecules, made of binary strings, are reported. Rules of evolution are designed such that the innovative collisions, i.e., those producing new species at the end of a reaction, become a negligible part of total number of collisions after a sufficiently large number of collisions have taken place. The distribution of species in the final mixture according to their bit size as well as the decay profile of the reactive and the innovative collisions are obtained. It is seen that the prescribed rules are sufficient to characterize a self-regulatory feature of the evolving system. Presented at the National Symposium on Evolution of Life.     

Physicochemical characterization of thermoresponsive poly(N-isopropylacrylamide)-poly(ethylene imine) graft copolymers

Synthetic polycations have shown promise as gene delivery vehicles but suffer from an unacceptable toxicity and low transfection efficiency. Novel architectures are being explored to increase transfection efficiency, including copolymers with a thermoresponsive character. The physicochemical characterization of a family of copolymers comprising a core of the cationic polymer poly(ethylene imine) (PEI) with differing thermoresponsive poly( N-isopropylacrylamide) (PNIPAM) grafts has been carried out using pulsed-gradient spin-echo NMR (PGSE-NMR) and small-angle neutron scattering (SANS). For the copolymers that have longer chain PNIPAM grafts, there is clear evidence of the collapse of the grafts with increasing temperature and the associated emergence of an attractive interpolymer interaction. These facets depend on the number of PNIPAM grafts attached to the PEI core. While a collapse in the smaller PNIPAM grafts is observed for the third polymer, there is no appearance of the interpolymer attractive interaction. These observations provide further insight into the association behavior of these copolymers, which is fundamental to developing a full understanding of how they interact with nucleic acids. Furthermore, the differing behaviors of the three copolymers over temperatures in which the PNIPAM blocks undergo coil-to-globule transitions is indicative of changes in the presentation of charged-core and hydrophobic chain components, which are key factors affecting nucleic acid binding and, ultimately, cell transfection ability.     

Multiple signaling pathways coordinately mediate reactive oxygen species dependent cardiomyocyte hypertrophy

The heart responds to an increased demand arising due to physiological stimuli or pathological insults by hypertrophy of myocytes. Reactive oxygen species (ROS) have recently been identified as the molecular intermediates in the translation of mechanical stimuli to cellular response. Different signal transduction pathways have been implicated with cardiac hypertrophy, prominent among them being, mitogen-activated protein kinase (MAPK), protein kinase C (PKC) and calcineurin. It remains unclear whether the ROS induced hypertrophy is mediated through one or more of these pathways. This study was taken up with the objective to affirm the role of ROS in the induction of cardiomyocyte hypertrophy and examine the contribution of specific pathways in the mediation of the hypertrophic response. The cellular response to enzyme-generated reactive oxygen species was examined in cultured cells from newborn rat heart. Pathway specific inhibitors were used to identify the role of each pathway in the mediation of cellular hypertrophy. Cellular hypertrophy in response to hypoxanthine-xanthine oxidase was prevented by inhibition of any one of the pathways; leading to the inference that oxidative stress induced hypertrophy is mediated by coordinative regulation of the three major pathways.     

Variation in mitogenic response of cardiac and pulmonary fibroblasts to cerium

Fibroproliferative response of rat heart and lung fibroblasts to the lanthanide cerium was examined, as the element has been implicated in the causation of cardiac and pulmonary fibrosis. Fibroblasts from both of the organs were morphologically identical, and the response to fetal bovine serum, a nonspecific mitogen, was also comparable. The oxygen radical generator (hypoxanthine + xanthine oxidase [Hyp.+XO]) induced a proliferative response that was neutralized in both cardiac and lung fibroblasts by free-radical scavengers. Superoxide dismutase was more effective than catalase in reducing the mitogenic effect of Hyp.+XO. The free-radical scavenger N-acetyl-l-cysteine neutralized the free-radical-mediated changes in pulmonary fibroblasts but had a negative effect in cardiac fibroblasts, indicating a tissue-dependent variation. Reactive oxygen species are known to act as biological mediators of tissue fibrosis induced by metallic compounds. Exposure to low levels of cerium (0.5 μM) stimulated a mitogenic response in cardiac fibroblasts, but the pulmonary fibroblasts were not sensitized by the element. Tissue-dependent variation in proliferative response to cerium shows a positive association with intracellular generation of reactive oxygen species. Fibrotic changes in cerium pneumoconiosis may either be replacement fibrosis following tissue damage or mediated by nonfibroblastic cells. The study confirms that cardiac and pulmonary fibroblasts are dissimilar cellular subtypes.