Litter decomposition in terrestrial ecosystems has a major role in the biogeochemical cycling of elements in the environment. Climatic features, like temperature, rainfall, humidity, and seasonal ...variations affect the rate of litter decomposition. This review attempts to understand the litter decomposition process in tropical forest ecosystems. It also reviews the influence of various factors on litter degradation and techniques used for assessing leaf litter decomposition. It is observed that very few studies were conducted on litter decomposition in forest ecosystems, such as tropical and temperate forests. Hence, comprehensive studies on litter degradation have to be undertaken in order to understand the turnover rate of nutrients and other elements in these sensitive ecosystems.
Room temperature rapid detection of toxic gases is still ambitious for real-time application. Recently, molybdenum disulfide transition dichalcogenides (MoS2 TMDCs) have been considered as a ...promising material for gas sensing application, owing to their high surface-to-volume ratio. However low response and incomplete recovery hinder their performance. In this work, we demonstrate MoS2 and cobalt incorporated MoS2 to enhance the sensing response and rapid recovery. Co-incorporated (7 at%) MoS2 showed 546.6% enhancement in response compared to pristine MoS2 for 100 ppm of NO2 gas at room temperature. The enhanced edge site presents in the Co-incorporated samples was the reason for excellent gas adsorption and increased response towards NO2 gas molecules. The stability analysis showed 70% of stability of a fabricated device. These results address a new pathway for an ideal gas sensor for room temperature application.
•The pristine MoS2 and co-incorporated MoS2 was successfully synthesized by hydrothermal method.•Studying the effect of cobalt incorporation in MoS2 and their gas sensing properties via home-made gas sensing unit.•The 7 at% of Co-incorporated MoS2 sample showed enhanced response of 51.08% in 10 s for 100 ppm of NO2 gas.•The uniqueness of our work is to fabricate room temperature gas sensor with enhanced sensitivity of 546.6%.
Background. Enteric fever caused by Salmonella Typhi remains a major public health problem in developing countries. Typbar-TCV is a single-dose typhoid Vi polysaccharide-tetanus toxoid conjugate ...vaccine for persons ≥6 months of age. Methods. Six hundred fifty-four healthy subjects aged 2–45 years enrolled in a double-blind, randomized controlled trial (RCT) received a single dose of Typbar-TCV or comparator "Vi polysaccharide" (Typbar), and 327 healthy subjects aged 6–23 months received a single dose of Typbar-TCV in an open-label trial (OLT); both received single- or multidose presentations from different lots. After 2 years, subsets in each group received a booster dose. The primary objective included analysis of geometric mean titer (GMTs) and 4-fold rise of anti-Vi serum immunoglobulin G (IgG) enzyme-linked immunosorbent assay titers over baseline (seroconversion SCN) 42 days after immunization. Results. Typbar-TCV recipients in the RCT attained higher anti-Vi IgG GMTs 42 days after immunization (SCN, 97%; GMT, 1293 95% confidence interval {CI}, 1153–1449) than recipients of (SCN, 93%; GMT, 411 95% CI, 359–471) (P<.001). Typbar-TCV was highly immunogenic in the OLT (SCN, 98%; GMT, 1937 95% CI, 1785–2103). Two years after vaccination, anti-Vi titers remained higher in Typbar-TCV subjects (GMT, 82 95% CI, 73–92); and exhibited higher avidity (geometric mean avidity index GMAI, 60%) than in Typbar recipients (GMT, 46 95% CI, 40–53; GMAI 46%) in the RCT (P < .001). OLT Typbar-TCV recipients achieved GMT of 48 (95% CI, 42–55) and GMAI of 57%. Typbar-TCV induced multiple IgG subclasses and strong booster responses in all ages. No serious vaccine-attributable adverse events were observed. Conclusions. Single-dose Typbar-TCV is well tolerated and induces robust and long-lasting serum anti-Vi IgG across age groups. Clinical Trials Registration. CTRI/2011/08/001957, CTRI/2014/01/004341.
Fault Tolerant Systems Israel Koren, C. Mani Krishna
2007, 2010, 2010-07-19T00:00:00, 2010-07-19, c2007
eBook
There are many applications in which the reliability of the overall system must be far higher than the reliability of its individual components. In such cases, designers devise mechanisms and ...architectures that allow the system to either completely mask the effects of a component failure or recover from it so quickly that the application is not seriously affected. This is the work of fault-tolerant designers and their work is increasingly important and complex not only because of the increasing number of “mission critical” applications, but also because the diminishing reliability of hardware means that even systems for non-critical applications will need to be designed with fault-tolerance in mind. Reflecting the real-world challenges faced by designers of these systems, this book addresses fault tolerance design with a systems approach to both hardware and software. No other text on the market takes this approach, nor offers the comprehensive and up-to-date treatment the authors provide. Students, designers and architects of high performance processors will value this comprehensive overview of the field.
Background. Japanese encephalitis (JE) is a vaccine-preventable acute disease. We report the results of a phase 2/3 trial of JENVAC, a Vero cell-derived vaccine developed using an Indian strain of JE ...virus (JEV). Methods. JENVAC was administered in 2 doses 28 days apart, and immunogenicity was compared to that from a single dose of SA-14-14-2, the only approved JE vaccine and regimen at the time in India. Results. After both the doses, seroconversion and seroprotection were >90% for JENVAC. For SA-14-14-2, seroconversion and seroprotection were 57.69% and 77.56%, respectively, on day 28 and 39.74% and 60.26%, respectively, on day 56. The geometric mean titers at day 28 and day 56 were 145.04 and 460.53, respectively, for JENVAC and 38.56 and 25.29, respectively, for SA-14-14-2. With a single dose of JENVAC, seroprotection titers lasted at least 12 months in >80% of the subjects. Following receipt of 2 doses, 61.17% of subjects retained seroprotection titers at 24 months, and immunogenicity criteria were higher than that for SA-14-14-2 at 12, 18, and 24 months each. Sera from JENVAC subjects neutralized JEV genotypes I, II, III, and IV equally well. Adverse events were not significantly different between the 2 vaccines. Conclusions. JENVAC elicits long-lasting, broadly protective immunity. Clinical Trials Registration. CTRI/2011/07/001855.
Layered transition metal dichalcogenide (TMD) materials possess novel and unique semiconducting properties when exfoliated into thin sheets or individual layers. The exfoliation leads to effective ...sensing towards gas molecule due to the increase in surface-active sites and edge zone disorders. In this work, we present exfoliation of bulk WS
2
sheets with liquid-based dispersion technique using facile bath sonication method for NO
2
molecule sensing. The exfoliated WS
2
nanosheets show reversible and selective response towards NO
2
gas molecules operating at room temperature. The sensitive film shows p-type characteristics providing sensor response rate around 27% for 10 ppm NO
2
with rapid response and recovery time around 45 s and 60 s, respectively. The sensitive response was further studied at high temperature of 150 °C showing a drastic increase in response rate as 45% with effective response and recovery time. This improvement in NO
2
gas sensing was attributed to the facile exfoliation of WS
2
nanosheets.
Nanostructured transition metal oxides have gained much attention in gas sensing applications due to their superior size-dependent adsorption and catalytic properties. Among them, WO3 based ...nanostructured thin films exhibit relatively high sensitivity towards toxic gases such as CO, NO2, NH3, and H2S, which makes them promising materials for gas sensing applications. Herein, we have attempted to prepare pure and yttrium-doped WO3 nanoplates by one-step hydrothermal method and their gas sensing performance was studied. The selectivity of the fabricated device was studied against NH3, NO2, and H2S gases. Pure and Y-doped samples exhibited an excellent selectivity towards NO2. The gas sensitivity, response time, and recovery time have been significantly enhanced for the Y-doped samples compared to the pure sample. Interestingly, the Y-doped sample (3 mM) exhibits an excellent response towards 20 ppm of NO2, which is comparatively 94- fold higher than pure WO3. The sample exhibited a short response T90 ~ 7 s and recovery time T10 ~ 38 s. The Y-2 sensor showed excellent repeatability and long-term stability. This is due to oxygen vacancy defects and the high surface area of the material. The enhancement in gas sensing performance has been explained by the gas sensing mechanism and work function measurement. The Y-doped WO3 nanostructures provide a new pathway for improving the performance of transition metal oxide-based gas sensors.
•The pure and Y-doped WO3 samples were prepared by hydrothermal method.•The enhancement in the NO2 gas sensing properties of the pure and Y-doped WO3 nano-plates were systematically investigated.•Pure and Y-doped WO3 samples exhibited the excellent the selectivity towards NO2.•The enhancement in the gas sensing properties has been explained by gas sensing mechanism and work function measurement.
Nitrogen dioxide (NO2) is one of the toxic gases produced by chemical industries, power plants, and vehicles. In this work, we demonstrate an inexpensive sensing platform for NO2 detection at room ...temperature (RT-32 °C) based on a charge transfer mechanism. Three-dimensional hierarchical SnS2 and SnS2/mesoporous TiO2 nanocomposites were synthesized via the solvothermal method. SnS2/20 wt% mesoporous TiO2 nanocomposites sample showed 245.4% enhanced response compared to pristine SnS2. The fabricated device exhibits excellent selectivity among all other interfering gases with one-month stability. The rapid response and enhanced response achieved were obtained for the minimum concentration of 2 ppm NO2. The formation of heterojunction between SnS2 and mesoporous TiO2 has a synergetic effect, providing more active sites and porous structures for the detection of NO2 gas molecules.
Antimicrobial activity of silver nanoparticles, which were synthesized by tri-sodium citrate assisted chemical approach, was evaluated. Chemical approach used for the synthesis of silver ...nanoparticles it was based on diminishment of silver nitrate in nearness of trisodium citrate without using any other capping and stabilizing agents. During the synthesis, four samples of silver nanoparticles were collected for comparative studies. The presence of silver nanoparticles was affirmed by analyzing the sample with X-ray diffraction, transmission electron microscopy, dynamic light scattering and ultra violet visible spectroscopy. Antimicrobial activity of some silver nanoparticle samples against two bacterial strains including Bacillus subtilis (which is Gram positive bacteria), Escherichia coli (which is Gram negative bacteria) and two fungal (yeast) strains namely Saccharomyce scerevisiae, and Candida albicans was determined. The silver nanoparticles showed the most significant inhibition activity against bacterial strains (Escherichia coli and Saccharomyces cerevisiae) in comparison to that activity towards fungal strains.
•Synthesis of silver nanoparticles (AgNPs) of different size by advanced chemical approach was applied.•Phases of pure Ag were observed by UV-Vis spectroscopy, XRD and TEM-SAD.•Antimicrobial activity of AgNPs against several bacterial and several fungal strains was determined.•Highest sensitivity towards AgNPs was observed for Escherichia coli, Saccharomyces cerevesiae and Candida albicans.
The world is currently facing an unprecedented global pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Predicting the next source of the pandemic can be very ...challenging. As vaccination is the best way to prevent an infectious disease, the development of an effective vaccine against SARS-CoV-2 can not only reduce the morbidity and mortality associated with it, but can also lessen the economic impact. As the traditional method of vaccine development takes many years for a vaccine to be available to the society, the vaccine development for SARS-CoV-2 should be speeded up using a pandemic approach with fast-track approvals from the regulatory authorities. Various challenges associated with developing a vaccine during the pandemic such as technological hurdles, clinical development pathways, regulatory issues, and support from global funding agencies are expressed here.
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