Antimicrobial activity of tissue and associated bacteria from benthic sea anemone Stichodactyla haddoni against microbial pathogens

Associated bacteria from Stichodactyla haddoni are found maximum in tentacle tissues than the body tissue. There are eight associated bacterial species viz., Alcaligenes sp, Corynebacterium sp, Aeromonas sp, Sporosarcina sp, Renibacterium sp, Camobacterium sp1, Camobacterium sp2 and Salinococcus sp were recorded. The culture extracts from the associated bacterial species showed sensitivity against human bacterial and fungalpathogens. However, the hexane tissue extract of sea anemone showed maximum sensitivity (24 mm dia.) against the fish bacterial pathogen Aeromonas hydrophila than the other chosen pathogens. Comparatively the tissue extracts showed promising antimicrobial sensitivity than the cell free extracts of associated bacteria, and hence, the tissue samples from the sea anemone Stichodactyla haddoni is recommended for further exploration of novel antimicrobial drugs than the associated bacteria.     

High reduction of 4-nitrophenol using reduced graphene oxide/Ag synthesized with tyrosine

There is a demand for the development of environmental friendly methods for the synthesis of graphene composites. Reduced graphene oxide/silver (RGO/Ag) nanocomposites are very good catalysts. Here, we propose a simple, green method for the synthesis of RGO/Ag nanocomposite using the amino acid tyrosine as bioreductant and stabilizing agent. RGO/Ag nanocomposite was characterized by using various analytical techniques and studied for its catalytic degradation of 4-nitrophenol. Results of attenuated total reflectance Fourier transform infrared spectroscopy and Zeta potential at ?55 mV reveal the surface capping of tyrosine onto the reduced graphene oxide nanosheets. RGO/Ag nanocomposites show excellent catalytic reduction of 4-nitrophenol with NaBH₄, when compared to actual individual silver nanoparticles.     

Unravelling the photoprotective effects of freshwater alga Nostoc commune Vaucher ex Bornet et Flahault against ultraviolet radiations

Environmental Science and Pollution Research - Several studies have suggested the direct relationship between skin complications, air pollution, and UV irradiation. UVB radiations cause various...     

Zinc oxide nanoparticles as efficient catalyst for the synthesis of novel di-spiroindolizidine bisoxindoles in aqueous medium

Environmental Chemistry Letters - Developing environmentally benign synthetic protocols such as reaction in water is a major challenge. However, many of the known methods carried out in an...     

Optimization of grid tied hybrid power system in smart premises

Tapping of renewable energy sources like solar and wind is given great priority by power producers all over the world. Technical problems of linking them to the grid are solved. The cost constraints of utilizing renewable energy at specific locations are to be determined. In this work, a model is developed for grid tied hybrid power system (HPS) consisting of photovoltaic (PV) module and wind mill at the roof top of smart premises. The grid is capable of delivering and receiving energy. Objective function is formed with constraints taking into account the cost of PV module, wind mill, and grid tied inverter with controller. The constraints are rating of HPS and energy that can be delivered to the grid. Using this model, case studies were conducted in three locations in India, each location having two different demands. The results are presented. With the optimal rating of HPS, results shows that, conventional energy cost is higher.     

Distribution of PCBs, HCHs and DDTs, and their ecotoxicological implications in Bay of Bengal, India

Analyses of environmentally persistent pollutants like polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, and dichlorodiphenyltrichloroethane (DDT) and its metabolites in seawater and sediment samples collected from six locations along the east coast of India were carried out using High-Resolution Gas Chromatograph with High-Resolution Mass Spectrometer (HRGC-HRMS). Sediment and water from Chennai harbour and Cuddalore fishing harbour contained higher concentration of all the compounds. The highest concentration (6570 pg/g dry weight) of total PCB was found in sediment from Chennai harbour followed by sediments sampled in Chennai (opposite to Cooum River mouth) (505 pg/g), Cuddalore fishing harbour (335 pg/g) and Mandapam (251 pg/g). Concentrations in other locations were two orders of magnitude lower than Chennai harbour. A distinct PCB distribution pattern in sediment was observed between harbours and other locations. Greater concentrations of tetra-, penta- and hexachlorobiphenyls were observed in sediments of harbours and opposite to Cooum river mouth, but in other locations lower chlorinated biphenyls (di, tri and tetra-) were more. In seawater, HCH concentration was greater than DDT, but it was quite opposite in sediments. Elevated levels of DDT in sediment were observed only at highly populated urban locations, reflecting the local usage and input of this pesticide. Based on sediment/water quality criteria/guidelines, some coastal locations of the Bay of Bengal could be designated as being polluted by DDTs and gamma-HCH (lindane), but not by PCBs. This investigation reveals the declining trend on the environmental burden of persistent pesticides in Indian marine environment. Data on the organochlorine concentrations found in this survey can be used as reference levels for future POPs monitoring programme.     

Cytogenetic results from the U.S. collaborative study on CVS

Cytogenetic data are presented for 11 473 chorionic villus sampling (CVS) procedures from nine centres in the U.S. NICHD collaborative study. A successful cytogenetic diagnosis was obtained in 99.7 per cent of cases, with data obtained from the direct method only (26 per cent), culture method only (42 per cent), or a combination of both (32 per cent). A total of 1.1 per cent of patients had a second CVS or amniocentesis procedure for reasons related to the cytogenetic diagnostic procedure, including laboratory failures (27 cases), maternal cell contamination (4 cases), or mosaic or ambiguous cytogenetic results (98 cases). There were no diagnostic errors involving trisomies for chromosomes 21, 18, and 13. For sex chromosome aneuploidies, one patient terminated her pregnancy on the basis of non-mosaic 47,XXX in the direct method prior to the availability of results from cultured cells. Subsequent analysis of the CVS cultures and fetal tissues showed only normal female cells. Other false-positive predictions involving non-mosaic aneuploidies (n = 13) were observed in the direct or culture method, but these cases involved rare aneuploidies: four cases of tetraploidy, two cases of trisomy 7, and one case each of trisomies 3, 8, 11, 15, 16,20, and 22. This indicates that rare aneuploidies observed in the direct or culture method should be subjected to follow-up by amniocentesis. Two cases of unbalanced structural abnormalities detected in the direct method were not confirmed in cultured CVS or amniotic fluid. In addition, one structural rearrangement was misinterpreted as unbalanced from the direct method, leading to pregnancy termination prior to results from cultured cells showing a balanced, inherited translocation. False-negative results (n = 8) were observed only in the direct method, including one non-mosaic fetal abnormality (trisomy 18) detected by the culture method and seven cases of fetal mosaicism (all detected by the culture method). Mosaicism was observed in 0.8 per cent of all cases, while pseudomosaicism (including single trisomic cells) was observed in 1.6 per cent of cases. Mosaicism was observed with equal frequency in the direct and culture methods, but was confirmed as fetal mosaicism more often in cases from the culture method (24 per cent) than in cases from the direct method (10 per cent). The overall rate of maternal cell contamination was 1.8 per cent for the culture method, but there was only one case of incorrect sex prediction due to complete maternal cell contamination which resulted in the birth of a normal male. The rate of maternal cell contamination was significantly higher in samples obtained by the transcervical sampling method (2. 16 per cent) than in samples obtained by the transabdominal method (0.79 per cent). From these data, it is clear that the culture method has a higher degree of diagnostic accuracy than the direct method, which should not be used as the sole diagnostic technique. The direct method can be a useful adjunct to the culture method, in which maternal cell contamination can lead to incorrect sex prediction and potentially to false-negative diagnostic results.     

Optimizing the position of insulating materials in flat roofs exposed to sunshine to gain minimum heat into buildings under periodic heat transfer conditions

Building roofs are responsible for the huge heat gain in buildings. In the present work, an analysis of the influence of insulation location inside a flat roof exposed directly to the sun’s radiation was performed to reduce heat gain in buildings. The unsteady thermal response parameters of the building roof such as admittance, transmittance, decrement factor, and time lags have been investigated by solving a one-dimensional diffusion equation under convective periodic boundary conditions. Theoretical results of four types of walls were compared with the experimental results available in literature. The results reveal that the roof with insulation placed at the outer side and at the center plane of the roof is the most energy efficient from the lower decrement factor point of view and the roof with insulation placed at the center plane and the inner side of the roof is the best from the highest time lag point of view among the seven studied configurations. The composite roof with expanded polystyrene insulation located at the outer side and at the center plane of the roof is found to be the best roof from the lowest decrement factor (0.130) point of view, and the composite roof with resin-bonded mineral wool insulation located at the center plane and at the inner side of the roof is found to be energy efficient from the highest time lag point (9.33 h) of view among the seven configurations with five different insulation materials studied. The optimum fabric energy storage thicknesses of reinforced cement concrete, expanded polystyrene, foam glass, rock wool, rice husk, resin-bonded mineral wool, and cement plaster were computed. From the results, it is concluded that rock wool has the least optimum fabric energy storage thickness (0.114 m) among the seven studied building roof materials.     

Zooplankton community structure across an eddy-generated upwelling band close to a tropical bay-mangrove ecosystem

Mesoscale eddies in the world’s oceans are ubiquitous and bring about episodic pulses of nutrients into the photic zone. Transient in nature, the role of eddy pumping in coastal enrichment via plankton production, and subsequent organic flux is not yet fully realised. In the context of a cyclonic cold-core eddy that propagates annually under the influence of the East India Coastal Current and enriches coastal waters in the western Bay of Bengal north of 16°N, a detailed study on zooplankton community structure along with phytoplankton composition and associated water quality was undertaken during April–May 2002 coinciding with the spring intermonsoon. Zooplankton samples were collected at 32 hydrographically different (salinity 24.5–35.6 PSU) GPS fixed locations representing bay-mangrove areas and nearshore waters (30 m) close to the River Godavari, which is one of India’s largest estuarine systems. During the study, the bay-coastal waters were typified by elevated nutrient levels (nitrate 10.73–22.04 μM), high salinity (27.98–35.52 PSU), and relatively low temperatures (30.63–31.40°C). Altogether, 95 zooplankton taxa were encountered with copepods forming the predominant population. Agglomerative Hierarchical Cluster Analysis (AHCA) and Non-metric Multidimensional Scaling (NMDS) based on Bray–Curtis similarity (PRIMER) analysis revealed appreciable alterations in zooplankton structure across bay-mangrove locations and coastal waters (Stress 0.11; ANOSIM test Global R: 0.94, P = 0.1%). Similarity Percentage (SIMPER) analysis revealed zooplankton associations through “discriminating species” for each location (Kakinada Bay, Cluster I, 27.9 ± 3.0 PSU; upwelling band, cluster II, 35.5 ± 0.2 PSU; offshore waters, cluster III, 34.2 ± 0.4 PSU; mangrove outlets, cluster IV, 32.7 ± 1.3 PSU and mangrove creeks, cluster V, 33.5 ± 0.6 PSU). The index of multivariate dispersion (IMD) illustrated high variability in zooplankton standing stock for mangrove/sea locations relative to the bay. Concurrent observations on phytoplankton revealed the importance of diatoms (r: 0.640, P ≤ 0.05). Within the eddy-generated band of upwelled water, a significant top-down control of diatoms by herbivorous zooplankton resulted in a comparative increase in abundance of dinophyceans. Based on zooplankton abundance data and species association patterns, it was possible to distinguish different zooplankton/copepod communities in accordance with mesoscale variability in physical, chemical and biological processes under tropical conditions. This was confirmed through canonical correspondence analysis (CCA) that represented coastal-offshore waters and the Bay environment in this area.     

Approach for the use of MSW settlement predictions in the assessment of landfill capacity based on reliability analysis

In the analysis and design of municipal solid waste (MSW) landfills, there are many uncertainties associated with the properties of MSW during and after MSW placement. Several studies are performed involving different laboratory and field tests to understand the complex behavior and properties of MSW, and based on these studies, different models are proposed for the analysis of time dependent settlement response of MSW. For the analysis of MSW settlement, it is very important to account for the variability of model parameters that reflect different processes such as primary compression under loading, mechanical creep and biodegradation. In this paper, regression equations based on response surface method (RSM) are used to represent the complex behavior of MSW using a newly developed constitutive model. An approach to assess landfill capacities and develop landfill closure plans based on prediction of landfill settlements is proposed. The variability associated with model parameters relating to primary compression, mechanical creep and biodegradation are used to examine their influence on MSW settlement using reliability analysis framework and influence of various parameters on the settlement of MSW are estimated through sensitivity analysis.