Heavy metal pollution in a sewage-fed lake of Bhopal, (M. P.) India

Shahpura Lake receives untreated domestic sewage from residential areas in Bhopal city. Analysis of water, plankton, fish and sediment reveals that the lake is contaminated by certain heavy metals. The concentrations of some of these metals including iron and manganese were within acceptable limits, whereas others including chromium, nickel, zinc and lead were not within acceptable water quality limits. Metal concentrations in the sewage inlet drain and lake sediment were compared with published criteria. The comparison revealed that the metals in the sediment ranged from the ‘non‐polluted’ to the ‘heavy pollution’ categories. The reference dose was calculated by the adoption of the United States Environmental Protection Agency reference dose factor, and the result reveals that the local population is not exposed to undue health risks. Concentrations of heavy metals in the water increased during the second year of the study, indicating an increase in the pollution load on the system. This might increase the bioaccumulation levels in fish and increase the actual dose of metals to which the local population will be exposed.     

Design and analysis of a hyphenation procedure

A hyphenation procedure is described wherein the search list includes exceptional words, prefixes, suffixes as well as a probabilistic Break-Value-Table. The list of prefixes and suffixes is augmented with what are termed as root words to achieve greater flexibility and accuracy. Importance is given to a number of ways whereby the overall algorithm can be speeded up; in this connection a number of rejection rules are formulated so that only the likely candidates are processed. The order of searching of the various data tables is also considered. A further refinement is tried wherein the common suffixes and common prefixes are given preferential treatment. The algorithm developed was tested on approximately 2,700 common English technical words and an attempt is made to analyse the incorrectly handled words.     

Effect of vacuum packaging on bandwidth of push–pull type capacitive accelerometer structure

Microsystem Technologies - This paper presents the effect of vacuum packaging on the band-width of push–pull type capacitive accelerometer structure. The accelerometer structure...     

A tri-layer approach to controlling nanopore formation in oxide supports

A novel tri-layer approach for immobilizing metal nanoparticles in SiO₂ supports is presented. In this work, we show that under rapid heating to temperatures of approximately 1,000 °C, metal nanoparticles less than 15 nm in size will entrench in the SiO₂ layer on a silicon wafer to create pores as deep as 250 nm. We studied and characterized this entrenching behavior and subsequent nanopore formation for a wide variety of metal nanoparticles, including Au, Ag, Pt, Pd, and Cu. We also demonstrate that an Al₂O₃ layer acts as a barrier to such pore formation. Thus, by creating a tri-layer architecture consisting of SiO₂ on Al₂O₃ on silicon wafers, we can control the depth to which nanoparticles entrench between 3–5 nm. This small range allows one to entrench particles for the purpose of immobilization but still present them above the surface. The two advances of moving into the sub-15 nm size regime and of controlled particle immobilization through entrenchment have important implications in studying site-isolated and stabilized metal nanoparticles for applications in sensing, separations, and catalysis.

     

Tailoring the microstructure and mechanical properties of arrays of aligned multiwall carbon nanotubes by utilizing different hydrogen concentrations during synthesis

We synthesize vertically aligned arrays of carbon nanotubes (CNTs) in a chemical vapor deposition system with floating catalyst, using different concentrations of hydrogen in the gas feedstock. We report the effect of different hydrogen concentrations on the microstructure and mechanical properties of the resulting material. We show that a lower hydrogen concentration during synthesis results in the growth of stiffer CNT arrays with higher average bulk density. A lower hydrogen concentration also leads to the synthesis of CNT arrays that can reach higher peak stress at maximum compressive strain, and dissipate a larger amount of energy during compression. The individual CNTs in the arrays synthesized with a lower hydrogen concentration have, on average, larger outer diameters (associated with the growth of CNTs with a larger number of walls), but present a less uniform diameter distribution. The overall heights of the arrays and their strain recovery after compression have been found to be independent of the hydrogen concentration during growth.     

Sensing the Messenger: Potential Roles of Cyclic-di-GMP in Rickettsial Pathogenesis

Pathogenic bacteria causing human rickettsioses, transmitted in nature by arthropod vectors, primarily infect vascular endothelial cells lining the blood vessels, resulting in ‘endothelial activation’ and onset of innate immune responses. Nucleotide second messengers are long presumed to be the stimulators of type I interferons, of which bacterial cyclic-di-GMP (c-di-GMP) has been implicated in multiple signaling pathways governing communication with other bacteria and host cells, yet its importance in the context of rickettsial interactions with the host has not been investigated. Here, we report that all rickettsial genomes encode a putative diguanylate cyclase pleD, responsible for the synthesis of c-di-GMP. In silico analysis suggests that although the domain architecture of PleD is apparently well-conserved among different rickettsiae, the protein composition and sequences likely vary. Interestingly, cloning and sequencing of the pleD gene from virulent (Sheila Smith) and avirulent (Iowa) strains of R. rickettsii reveals a nonsynonymous substitution, resulting in an amino acid change (methionine to isoleucine) at position 236. Additionally, a previously reported 5-bp insertion in the genomic sequence coding for pleD (NCBI accession: {"type":"entrez-nucleotide","attrs":{"text":"NC_009882","term_id":"157827862"}}NC_009882) was not present in the sequence of our cloned pleD from R. rickettsii strain Sheila Smith. In vitro infection of HMECs with R. rickettsii (Sheila Smith), but not R. rickettsii (Iowa), resulted in dynamic changes in the levels of pleD up to 24 h post-infection. These findings thus provide the first evidence for the potentially important role(s) of c-di-GMP in the determination of host-cell responses to pathogenic rickettsiae. Further studies into molecular mechanisms through which rickettsial c-di-GMP might regulate pathogen virulence and host responses should uncover the contributions of this versatile bacterial second messenger in disease pathogenesis and immunity to human rickettsioses.     

Connected component labeling on a 2D grid using CUDA

Connected component labeling is an important but computationally expensive operation required in many fields of research. The goal in the present work is to label connected components on a 2D binary map. Two different iterative algorithms for doing this task are presented. The first algorithm (Row-Col Unify) is based upon the directional propagation labeling, whereas the second algorithm uses the Label Equivalence technique. The Row-Col Unify algorithm uses a local array of references and the reduction technique intrinsically. The usage of shared memory extensively makes the code efficient. The Label Equivalence algorithm is an extended version of the one presented by Hawick et al. (2010) [3]. At the end the comparison depending on the performances of both of the algorithms is presented.     

Comparative assessment of soybean meal with high and low glucosinolate rapeseed–mustard cake as protein supplement on performance of growing crossbred calves

BACKGROUND: Feeding of high glucosinolate rapeseed–mustard cakes (RMCs) imparts adverse effects on dry matter (DM) intake, health and overall performance of animals. Recently, plant breeding efforts have resulted in many cultivars of RMCs containing low to moderate levels of glucosinolate in India. The feeding value of RMC cultivars with high and low glucosinolate was evaluated relative to commonly used soybean meal as a protein supplement in growing crossbred calves. RESULTS: Eighteen growing crossbred calves (62.9 ± 3.8 kg body weight) were randomly allocated to three dietary treatments SBM, LG and HG containing soybean meal, low glucosinolate B. napus (15 µmol glucosinolates g^?1) and high glucosinolate B. juncea (135 µmol glucosinolates g^?1), respectively. Although daily intake of total DM and wheat straw did not differ (P > 0.05) among the dietary treatments, intake (g/kgW^0.75) of concentrate moiety decreased quadratically (P < 0.01) with increasing glucosinolate levels in diets. Nutrient digestibility and balances of N, Ca and P by calves were similar (P > 0.05) among dietary treatments. However, average daily gain (g) decreased and feed conversion ratio values increased quadratically (P < 0.05) with increasing glucosinolate levels. Serum metabolic profile and triiodothyronine remained within the normal range; however, thyroxine changed quadratically. CONCLUSION: The results suggested that while high glucosinolate RMCs may reduce the palatability and consequently growth rate in crossbred calves, SBM can be replaced completely by low glucosinolate rapeseed without compromising their performance. Copyright © 2008 Society of Chemical Industry