Groundwater aquifers serve as the primary source of potable water for the vast majority of the population in the Brahmaputra River valley. However, these groundwater reserves form a substantial part ...of a rapidly weathering alluvial drainage resulting in major contamination by Arsenic (As) and associated heavy metals thereby raising key concern on their safety and sustained usage. The current study entails a comprehensive qualitative analysis of the potable groundwater reserves using a combination of geographical information system (GIS) and geochemical approaches to determine the severity of groundwater contamination by As and other heavy metals in a total of twenty administrative districts of Assam, India. Furthermore, the groundwater solute chemistry and water quality status in the 20 districts of the study area, which encompasses the Brahmaputra River valley, was also assessed to evaluate the sustainability of these potable groundwater reserves. The findings show that the groundwater aquifers present in these districts of the Brahmaputra River valley in Assam are severely contaminated with As with the highest concentration at ∼352.56 ppb being observed in the district of Nagaon. The districts of Tinsukia, Dibrugarh, Sivasagar, Dhemaji, Lakhimpur, Jorhat, Golaghat, Sonitpur, Nagaon, Morigaon, Darrang, Udalguri, Kamrup, Nalbari, and Baksa also showed the presence of elevated levels of dissolved As which on an average exceeded the WHO permissible limit of 10 parts per billion as well as the Bureau of Indian Standards limit of 50 parts per billion. Moreover, notable contamination by other heavy metals including lead, manganese, iron, and zinc exceeding the WHO and BIS prescribed limits were prominent. Also, the groundwater was found to harbour elevated concentrations of ions such as HCO3−, Ca2+ and Mg2+ which impart severe restrictions on to the safety, aesthetics and palatability of these potable water reserves. Furthermore, the dissolved As content was found to exhibit a significant correlation to the elemental contaminants such as iron and manganese suggesting that the reductive dissolution of iron oxyhydroxides may serve as the underlying mechanism for the As enrichment of these groundwater reserves. Additionally, the impact assessment study through the spatial distribution of the groundwater quality index (GWQI) of the areas studied showed that the groundwater reserves in the majority of the administrative districts are unfit for human consumption, without the intervention through requisite water treatment and/or sustainable remediation approaches. These findings indicate the need for serious introspection and reconsiderations on the part of the stakeholders for the sustainable use of these groundwater resources for anthropogenic activities.
•Spatially interpolated distribution maps for groundwater As, heavy metals, pH and depth developed.•16 out of 20 districts surveyed had severe As contamination, highest being ∼352 ppb.•10 new districts found to be affected by As contamination, in the comprehensive study.•Modeling of groundwater As showed correlation with Mn and Fe.•Groundwater Quality Indexing shows most groundwater reserves unfit for human consumption.
The magnetic abrasive machining (MAM) process is a highly developed unconventional machining process. It is frequently used in manufacturing industries for nanometer range surface finishing of ...workpiece with the help of Magnetic abrasive particles (MAPs) and magnetic force applied in the machining zone. It is precise and faster than conventional methods and able to produce defect free finished components. This paper provides a comprehensive review on the recent advancement of MAM process carried out by different researcher till date. The effect of different input parameters such as rotational speed of electromagnet, voltage, magnetic flux density, abrasive particles size and working gap on the performances of Material Removal Rate (MRR) and surface roughness (Ra) have been discussed. On the basis of review, it is observed that the rotational speed of electromagnet, voltage and mesh size of abrasive particles have significant impact on MAM process.
Multiwalled carbon nanotube/hectorite hybrid filler (HMH) was prepared by simple dry grinding method. It was subsequently used for the reinforcement of technologically compatible acrylonitrile ...butadiene rubber (NBR)/ ethylene-co-vinyl acetate (EVA) blend through solution intercalation method. Analysis of the prepared blend nanocomposites confirms homogeneous dispersion of the constituent fillers in the polymer matrix and significant interaction between two types of constituent fillers. Mechanical properties of NBR/EVA blend are significantly improved with HMH content up to 4 wt.% followed by reversion. Maximum improvement observed in tensile strength, elongation at break and toughness are 106%, 37% and 171% respectively without significant rise in Young’s modulus. Results also show best dynamic mechanical and dielectric response at 4 wt.% and 3 wt.% HMH content respectively. Enhanced mechanical, dynamic mechanical and dielectric properties of the blend nanocomposites attained may be attributed to fair degree of compatibility between the two polymer matrices, homogeneous dispersion of fillers and improved polymer-filler interaction.
Exclusive b → sγ decays at Belle Dutta, D; Bhuyan, B
Journal of physics. Conference series,
07/2015, Volume:
631, Issue:
1
Journal Article
Peer reviewed
Open access
We report results on two exclusive b → sγ decays, namely B0s → γ and B0s → γγ at Belle. For this study, we have used 121.4 fb-1 of (5S) data collected with the Belle detector at the KEKB ...asymmetric-energy e+e- collider. Calculations within the Standard Model framework predict the B0s → γ branching fraction to be in the range (3.9 - 4.3) x 10-5 and the B0s → γγ branching fraction to be in the range (0.18 - 2.45) x 10-6. The B0s → γ branching fraction is measured as (3.6 ± 0.5 ± 0.3 ± 0.6) x 10-5, where the first uncertainty is statistical, the second is systematic and the last one is due to the uncertainty in the fraction of events. This result agrees with the theoretical predictions and other experimental results. We observe no statistically significant signal for B0s → γγ and have thus set a 90% confidence-level upper limit on its branching fraction at 3.1 x 10-6. This improves on the previous result by a factor of about 3 and is the most stringent limit till date.
Hydrocarbonoclastic bacterial strains were isolated from rhizosphere of plants growing in crude oil-contaminated sites of Assam, India. These bacteria showed plant growth-promoting attributes, even ...when exposed to crude oil. Two independent pot trials were conducted to test the rhizodegradation ability of the bacterial consortium in combination of plants
Azadirchta indica
or
Delonix regia
in crude oil-contaminated soil. Field experiments were conducted at two crude oil-contaminated agricultural field at Assam (India), where plants (
A. indica
or
D. regia
) were grown with the selected bacterial consortium consisting of five hydrocarbonoclastic bacterial isolates (
Gordonia amicalis
BB-DAC,
Pseudomonas aeruginosa
BB-BE3,
P. citronellolis
BB-NA1,
Rhodococcus ruber
BB-VND, and
Ochrobactrum anthropi
BB-NM2), and NPK was added to the soil for biostimulation. The bacterial consortium-NPK biostimulation led to change in rhizosphere microbiome with enhanced degradation of petroleum hydrocarbons (PHs) in soils contaminated with crude oil. After 120 days of planting
A. indica
+ consortium + NPK treatment, degradation of PHs was found to be up to 67%, which was 55% with
D. regia
with the same treatment. Significant changes in the activities of plant and soil enzymes were also noted. The shift is bacterial community was also apparent as with
A. indica
, the relative abundance of Proteobacteria, Actinobacteria, and Acidobacteria increased by 35.35%, 26.59%, and 20.98%, respectively. In the case of
D. regia
, the relative abundance of Proteobacteria, Actinobacteria, and Acidobacteria were increased by 39.28%, 35.79%, and 9.60%, respectively. The predicted gene functions shifted in favor of the breakdown of xenobiotic compounds. This study suggests that a combination of plant-bacterial consortium and NPK biostimulation could be a productive approach to bioengineering the rhizosphere microbiome for the purpose of commercial bioremediation of crude oil-contaminated sites, which is a major environmental issue faced globally.
Introduction: Type 2 diabetes mellitus (T2DM) has been found to be associated with poor quality of life (QOL). The aim of this study was to measure QOL in T2DM patients and examine if the patients' ...socio demographic, diabetes-related clinical characteristics and insulin usage are associated with better quality of life. Materials and Methods: This clinic based cross-sectional study analyzed data from outpatients with T2DM attending a referral clinic between January and June 2016. Association between Diabetes Attitudes, Wishes and Needs (DAWN) QOL and few demographic, socioeconomic, clinical and biochemical predictors were examined using multivariate logistic regression model. A total of 518 patients completed the interview. Results: The HbA1c level of insulin ± oral anti-diabetic (OAD) cohort was significantly lower (7.89 ± 1.98) than the OAD cohort (8.79 ± 1.96), P < 0.001. Compared to their counterparts in the OAD cohort, patients on insulin were older with longer duration of diabetes mellitus. Co-morbid confounders like obesity, hypoglycemia, and blood pressure control or socio demographic confounders like income, education were almost similar in both the cohorts. The incidence of hypertension, coronary artery disease (CAD) and statin usage was significantly higher in the insulin cohort. The overall composite DAWN QOL scores of the insulin ± OAD cohort (25.42 ± 4.35) was marginally higher than that of the OAD cohort (23.62 ± 5.06) (P = 0.067). Analog insulin users were also found to have significantly higher composite DAWN QOL scores compared to human insulin users (25.77 ± 5.73 vs.24.13 ± 4.88, P = 0.037). Conclusions: The insulin cohort, despite being older and having longer duration of diabetes, had significantly higher diet compliance score, and enhanced QOL owing to better diabetes-related knowledge and treatment adherence characteristics than non-insulin users. Questionnaires-based evaluation of QOL can provide better understanding of the patient's experience of the illness, self-care, psychological and emotional functioning, and choice of therapeutic modality enhancing the quality of care.
Linagliptin, a dipeptidyl peptidase 4 (DPP 4) inhibitor with a long terminal half life, significantly inhibits the DPP 4 enzyme at a steady state up to 48 h after the last dose. The present case ...series examined the hypothesis that linagliptin retains its efficacy during alternate day dosing in type 2 diabetes patients when switched over from once daily (OD) dosing. Eight type 2 diabetes patients maintaining stable glycosylated hemoglobin (HbA1c) with acceptable fasting plasma glucose and postprandial glucose levels and receiving linagliptin 5 mg OD for at least 6 weeks, with a stable dose of concomitant antidiabetic medications were given linagliptin 5 mg every alternate day. The median HbA1c while on the OD regimen was 6.1% (43 mmol/mol) (range: 5.8-6.9% 40-52 mmol/mol) and median duration of diabetes was 7 years (range: 0.75-16 years). After a median follow-up period of 21weeks,the glycemic control was maintained in all patients similar to their baseline values (median HbA1c: 6.0% 42 mmol/mol, range: 5.1-7.1% 32-54 mmol/mol). The body weight, fasting, and random glucose levels at baseline were also well maintained at the end of treatment. Optimal glycemic status maintained in our study population favors our hypothesis that linagliptin used alternate daily after switching from initial OD dose of the drug in patients on a stable background antidiabetic medications retains its efficacy. Paradoxically, alternate day dosing may affect compliance if the patient forgets when they took the last dose. Further studies including larger cohorts are needed to validate this finding and identify patients who can benefit from the alternate day regimen.
The experimental results on the ratios of branching fractions R(D)=B(Bover ¯→Dτ^{-}νover ¯_{τ})/B(Bover ¯→Dℓ^{-}νover ¯_{ℓ}) and R(D^{*})=B(Bover ¯→D^{*}τ^{-}νover ¯_{τ})/B(Bover ¯→D^{*}ℓ^{-}νover ...¯_{ℓ}), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D^{*}), based on a data sample containing 772×10^{6} BBover ¯ events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D^{*})=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D^{*}), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D^{*}) performed to date as well as the first result for R(D) based on a semileptonic tagging method.
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