| 671. |
- Kröll, T., et al.
(författare)
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Transfer Reactions on Neutron-rich Nuclei at REX-ISOLDE
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 363-368 461
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Konferensbidrag (refereegranskat)abstract
- We report on one- and two-neutron transfer reactions to study the single-particle properties of nuclei at the border of the "island of inversion". The (d,p)- and (t,p)-reactions in inverse kinematics on the neutron-rich isotope Mg-30, delivered as radioactive beam by the REX-ISOLDE facility, have been investigated. The outgoing protons have been detected and identified by a newly built array of Si detectors. The gamma-decay of excited states has been detected in coincidence by the MINIBALL array. First results for Mg-31 and from the search for the second, spherical, 0(+) state in Mg-32 are presented.
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| 672. |
- Kumar, Manoj, et al.
(författare)
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Arsenic distribution and mobilization : A case study of three districts of uttar pradesh and bihar (india)
- 2015
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Ingår i: Safe and Sustainable Use of Arsenic-Contaminated Aquifers in the Gangetic Plain. - Cham : Springer Publishing Company. - 9783319161242 - 9783319161235 ; , s. 111-123
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Tectonic evolution of Himalayas is related to high erosional potential and substantial sediment transport. Fluvial deposition of clastic material in the Middle Gangetic plain (MGP) is mainly governed by crustal deformation and climatic condition of Himalayas (Singh M, Singh IB, Müller G, Geomorphology 86:144-175, 2007). Seven large Asian rivers-Ganga, Indus, Brahmaputra, Yangtze, Huang He or Yellow River, Salween and Mekong-are fed by Himalayan glaciers which are supplying ~30 % of the global sediments to the ocean (Milliman JD, Meade RH, J Geol 9:1-19, 1983; Singh VB, Ramanathan AL, Pottakkal JG, Kumar M, J Asian Earth Sci 79:224-234, 2014, 2005). High flux of sediment transported from different terrain of Himalayas is product of geologically young rock formation (Singh VB, Ramanathan AL, Pottakkal JG, Kumar M, J Asian Earth Sci 79:224-234, 2014). It provides an opportunity to study the fluvial system and post-depositional changes in sediment water interaction depending on the degree of mobility of element under the altered environmental conditions. Arsenic (As) contamination of groundwater is a global problem. Understanding of As mobilization from sediments to As-contaminated aquifers is important for water quality management in areas of MGP of India.
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| 673. |
- Kumar, M., et al.
(författare)
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Groundwater evolution and its utility in upper Ganges-Yamuna Alluvial plain of Northern India, India : Evidence from solute chemistry and stable isotopes
- 2018
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Ingår i: Groundwater for Sustainable Development. - : Elsevier BV. - 2352-801X. ; 7, s. 400-409
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Tidskriftsartikel (refereegranskat)abstract
- The current study was focused on the characterization of recharge, weathering processes and to check the aptness of groundwater for household and agriculture utility in the Chhaprola industrial area located in Gautam Buddha Nagar district of Uttar Pradesh, India. Groundwater samples (n = 33) were analyzed for major cations and anions from which (n = 22) were analyzed for stable isotopic records (δ2H and δ18O). Solute chemistry revealed neutral to moderately basic nature (pH ranged 6.4–8.8) and showed a higher (ranged 552–3130 µS/cm) of electrical conductivity. Isotopic signals ranged from − 8.7 to − 3.3‰ for δ18O and − 60.1 to − 37‰ for δ2H. Bivariate plot of stable isotopes (δ18O and δ2H) showed that majority of the samples fell below the global meteoric water line (GMWL) and local meteoric water line (LMWL) of New Delhi, indicating enrichment of heavier isotopes in the aquifers, which explain that recharging water, has undergone evaporation before recharging the aquifer. Monsoonal precipitation was observed as the major source of aquifer recharge in the surveyed area. Vertical hydraulic connectivity of the aquifer layers was traced with the help of isotopic record which exhibited a more negative intercept for shallow depth tube well than the middle depth tube well. About 76% of the samples exhibited negative Schoeller index thereby indicated cation-anion exchange reactions while the remaining samples depicted the Base Exchange Reactions. Sodium-normalized Ca versus Na-normalized Mg and HCO3, indicated an equal contribution of silicate and carbonate type weathering on global-average weathering system. About 52% of the groundwater samples fell into the Ca-HCO3 - water type while remaining samples fell into 33% and 15% of Na-HCO3 and Mg-HCO3 type, respectively. Water quality indices (viz. residual sodium carbonate, Kelly index, permeability index, magnesium hazard, and Chloroalkaline indices) revealed unsuitability of the groundwater for drinking and irrigation purpose at few locations.
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| 674. |
- Kumar, Rajiv, et al.
(författare)
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Effect of chromium and aluminum addition on anisotropic and microstructural characteristics of ball milled nanocrystalline iron
- 2016
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 671, s. 164-169
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Tidskriftsartikel (refereegranskat)abstract
- Prior studies on synthesis of nanocrystalline elements have discussed the effect of ball milling on lattice parameter, crystallite size, and micro-strain. For elemental milled powders, the anisotropic peak broadening does not change with increasing milling time. However, the effect of alloying addition on the anisotropic behavior of ball milled nanocrystalline powders remains an unexplored area. Here we report the effect of chromium and aluminum addition on the anisotropic behavior of iron in nanocrystalline Fe–20Cr–5Al (wt%) alloy powders synthesized by ball milling. The experimental results show that the anisotropic behavior of iron changes towards isotropic with milling. This change was also correlated to the theoretically calculated anisotropic factor from the change in elastic constant of iron due to milling. Addition of alloying elements exhibited a monotonic rise in the lattice parameter with crystallite size, which was attributed to the excess grain boundary interfacial energy and excess free volume at grain boundaries. Transmission electron microscopy image confirmed the crystallite size and nature of dislocation obtained using modified Williamson-Hall method.
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| 675. |
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| 676. |
- Kumar, S., et al.
(författare)
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Nitrogen uptake potential under different temperature-salinity conditions: Implications for nitrogen cycling under climate change scenarios
- 2018
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Ingår i: Marine Environmental Research. - : Elsevier BV. - 0141-1136 .- 1879-0291. ; 141:October, s. 196-204
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Tidskriftsartikel (refereegranskat)abstract
- As projected by climate change models, increase in sea surface temperature and precipitation in the future may alter nutrient cycling in the coastal regions due to potential changes in phytoplankton community structure and their ability to assimilate nitrogen (N) and carbon (C). An experiment simulating different temperature and salinity conditions (28 degrees C-35 ambient conditions, 28 degrees C-31, 31 degrees C-35 and 31 degrees C-31) in mesocosms containing 1000 L of coastal water from the Arabian Sea was performed and N uptake rates were measured using N-15 tracer technique on 2nd, 5th, 7th and 10th day of the experiment. The results show that, under all conditions, the total N (NO3- + NH4+) uptake rates were lower in the beginning and on the final day of the tracer experiment, while it peaked during middle, consistent with chlorophyll a concentrations. Total N uptake rate was significantly lower (p = 0.003) under ambient temperature -lower salinity condition (28 degrees C-31) than the others. This indicates that lowering of salinity in coastal regions due to excessive rainfall in the future may affect the N uptake potential of the phytoplankton, which may change the regional C and N budget.
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| 677. |
- Kumar, Varun, et al.
(författare)
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Highly time-resolved chemical speciation and source apportionment of organic aerosol components in Delhi, India, using extractive electrospray ionization mass spectrometry
- 2022
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 22:11, s. 7739-7761
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the Indian capital city of Delhi has been impacted by very high levels of air pollution, especially during winter. Comprehensive knowledge of the composition and sources of the organic aerosol (OA), which constitutes a substantial fraction of total particulate mass (PM) in Delhi, is central to formulating effective public health policies. Previous source apportionment studies in Delhi identified key sources of primary OA (POA) and showed that secondary OA (SOA) played a major role but were unable to resolve specific SOA sources. We address the latter through the first field deployment of an extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF) in Delhi, together with a high-resolution aerosol mass spectrometer (AMS). Measurements were conducted during the winter of 2018/19, and positive matrix factorization (PMF) was used separately on AMS and EESI-TOF datasets to apportion the sources of OA. AMS PMF analysis yielded three primary and two secondary factors which were attributed to hydrocarbon-like OA (HOA), biomass burning OA (BBOA-1 and BBOA-2), more oxidized oxygenated OA (MO-OOA), and less oxidized oxygenated OA (LO-OOA). On average, 40 % of the total OA mass was apportioned to the secondary factors. The SOA contribution to total OA mass varied greatly between the daytime (76.8 %, 10:00–16:00 local time (LT)) and nighttime (31.0 %, 21:00–04:00 LT). The higher chemical resolution of EESI-TOF data allowed identification of individual SOA sources. The EESI-TOF PMF analysis in total yielded six factors, two of which were primary factors (primary biomass burning and cooking-related OA). The remaining four factors were predominantly of secondary origin: aromatic SOA, biogenic SOA, aged biomass burning SOA, and mixed urban SOA. Due to the uncertainties in the EESI-TOF ion sensitivities, mass concentrations of EESI-TOF SOA-dominated factors were related to the total AMS SOA (i.e. MO-OOA + LO-OOA) by multiple linear regression (MLR). Aromatic SOA was the major SOA component during the daytime, with a 55.2 % contribution to total SOA mass (42.4 % contribution to total OA). Its contribution to total SOA, however, decreased to 25.4 % (7.9 % of total OA) during the nighttime. This factor was attributed to the oxidation of light aromatic compounds emitted mostly from traffic. Biogenic SOA accounted for 18.4 % of total SOA mass (14.2 % of total OA) during the daytime and 36.1 % of total SOA mass (11.2 % of total OA) during the nighttime. Aged biomass burning and mixed urban SOA accounted for 15.2 % and 11.0 % of total SOA mass (11.7 % and 8.5 % of total OA mass), respectively, during the daytime and 15.4 % and 22.9 % of total SOA mass (4.8 % and 7.1 % of total OA mass), respectively, during the nighttime. A simple dilution–partitioning model was applied on all EESI-TOF factors to estimate the fraction of observed daytime concentrations resulting from local photochemical production (SOA) or emissions (POA). Aromatic SOA, aged biomass burning, and mixed urban SOA were all found to be dominated by local photochemical production, likely from the oxidation of locally emitted volatile organic compounds (VOCs). In contrast, biogenic SOA was related to the oxidation of diffuse regional emissions of isoprene and monoterpenes. The findings of this study show that in Delhi, the nighttime high concentrations are caused by POA emissions led by traffic and biomass burning and the daytime OA is dominated by SOA, with aromatic SOA accounting for the largest fraction. Because aromatic SOA is possibly more toxic than biogenic SOA and primary OA, its dominance during the daytime suggests an increased OA toxicity and health-related consequences for the general public.
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| 678. |
- Kumari, G., et al.
(författare)
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Impact of Counseling based Edu Vaccine on the Control and Prevention of COVID-19 pandemic
- 2023
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Ingår i: Biomedical and Pharmacology Journal. - : Oriental Scientific Publishing Company. - 0974-6242. ; 16:4, s. 2069-2081
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Tidskriftsartikel (refereegranskat)abstract
- Millions of people throughout the world are affected by the coronavirus outbreak brought on by the pandemic Coronavirus Disease (COVID-19), which is the first significant human catastrophe in history. This study aimed to assess the effect of counseling based Edu Vaccine on prevention and control of COVID-19 pandemic. This pre and post designed, prospective, study was conducted in different states of India using an online survey. A 30-items questionnaire as an instrument was sent to 1597 potential responders. The responded participants were enrolled as study participants and divided into counseling and non-counseling groups. The obtained data were analyzed using SPSS version 21. Chi-square test was used to assess the level of association among variables and independent t-test was used to compare participants' demographic and socioeconomic measurements. Out of 1597 only 829 participants responded and completed the survey questionnaire. At baseline, half of the population found that the symptoms of COVID include fever, cough and trouble breathing, but after the counseling a significant change was observed (p<0.001) in the counseling group. 91.7% population were agreed that social distancing, maintain hygiene and public awareness can help to control the community spread or 3rd stage of COVID-19. Around 96 % of the population in the counseling group was aware of the preventive measures recommended by WHO to avoid COVID-19 infection after the counseling. A significant improvement was observed in general population's the knowledge levels regarding COVID-19 and its preventive measures. We observed that people were aware of COVID-19 and preventive masseurs but they do not adhere so there is an urgent need to continuous educational campaigns with follow-ups that target less-educated, lower-income population and further studies are warranted.
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| 679. |
- Kurzawa-Akanbi, M., et al.
(författare)
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Altered ceramide metabolism is a feature in the extracellular vesicle-mediated spread of alpha-synuclein in Lewy body disorders
- 2021
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 142, s. 961-984
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in glucocerebrosidase (GBA) are the most prevalent genetic risk factor for Lewy body disorders (LBD)-collectively Parkinson's disease, Parkinson's disease dementia and dementia with Lewy bodies. Despite this genetic association, it remains unclear how GBA mutations increase susceptibility to develop LBD. We investigated relationships between LBD-specific glucocerebrosidase deficits, GBA-related pathways, and alpha-synuclein levels in brain tissue from LBD and controls, with and without GBA mutations. We show that LBD is characterised by altered sphingolipid metabolism with prominent elevation of ceramide species, regardless of GBA mutations. Since extracellular vesicles (EV) could be involved in LBD pathogenesis by spreading disease-linked lipids and proteins, we investigated EV derived from post-mortem cerebrospinal fluid (CSF) and brain tissue from GBA mutation carriers and non-carriers. EV purified from LBD CSF and frontal cortex were heavily loaded with ceramides and neurodegeneration-linked proteins including alpha-synuclein and tau. Our in vitro studies demonstrate that LBD EV constitute a "pathological package" capable of inducing aggregation of wild-type alpha-synuclein, mediated through a combination of alpha-synuclein-ceramide interaction and the presence of pathological forms of alpha-synuclein. Together, our findings indicate that abnormalities in ceramide metabolism are a feature of LBD, constituting a promising source of biomarkers, and that GBA mutations likely accelerate the pathological process occurring in sporadic LBD through endolysosomal deficiency.
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| 680. |
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