116 research outputs found
Isolation and Screening of Antibiotics Producing Streptomyces spp from the Soil Collected around the Root of Alnus nepalensis from Godawari
Actinomycetes are considered as the most invaluable prokaryotes whose genome mining show a great number of putative secondary metabolite biosynthesis pathways as well as gene clusters ranging from 20 to 50 per genome. The genus Streptomyces has been explored for its ability to produce 60% antibiotics worldwide. Alnus nepalensis (Alder) has been found to harbor diverse Eubacteria in its rhizosphere. To evaluate the antibiotic production potential from Actinomycetes, we collected soil samples from rhizosphere (5-7 cm deep) of Alder tree. Primary screening was done by cross-streak method against Multidrug Resistant (MDR) such as Methicillin resistant Staphylococcus auereus (MRSA), Vancomycin resistant Enterococcus feacalis (VRE), Imepenem resistant Acinetobacterbaumannii, Vancomycin resistant Klebsiella pneumonia and Imepenem resistant E. coli as well as Non-MDRs (E. coli, Bacillus subtilis, Klebsiella pneumoniae, S. aeureu and Enterococcus feacalis). Extraction of antibiotics was done using rota-vapour from extract obtained by solid-substrate fermentation technique followed by solvent extraction. Secondary screening was done using well diffusion assay against MDRs. Among total of 40 isolates of Actinomycetes recovered, 14 showed remarkable zone of inhibition (ZOI) to various MDRs. NASA 303 showed 26 mm of ZOI against VRE, NASA 101 had ZOI of 34 mm against MRSA, NASA 319 had 33.7 mm ZOI against Imepenem resistant E. coli, NASA 306 had 36 mm of ZOI against Vancomycin resistant Klebsiella pneumoniae, and NASA 108 showed ZOI of 29.6 mm against Imepenem resistant E. faecalis. This investigation revealed that the Actinomycetes found in Rhizosphere of Alder tree had MDR killing potent antibiotics, which needs to be further explored
Effects of potassium levels on growth and productivity of potato varieties in inner terai of Nepal
Potassium is an essential nutrient for potato due to its direct effects on the growth, yield and quality of potato tubers. This study was carried out at Lamahi, Dang Nepal during winter season of 2018. Two potato variety (Local and Cardinal) and five levels of potassium (30, 40, 60, 80 and 100 kg K2O/ha) were evaluated in two factorial randomized block design with three replications. The application of potassium at 100 kg/ha produced significantly highest plant canopy, stem diameter and leaf length for the both varieties. The highest tuber number per plant (10.3 for Local and 17.6 for cardinal) and tuber weight (19.7 g for Local and 49 g for Cardinal) were obtained with the application of 100 kg K2O/ha. The highest gross margin was found with this level of potassium. Therefore, farmers should apply 100 kg K2O to potato to achieve maximum production and benefit. 
Preparation of floral calendar of bee flora available in Lamjung district, Nepal
Between March and May 2022, researchers conducted a broad survey in the Lamjung district to ascertain the presence and accessibility of bee-friendly flora to compile a floral calendar. In the PMAMP Bee Zone, 62 respondents were chosen for the interview through a simple random sampling approach, from a pool of 382 registered beekeepers. Primary data collection involved using personal interviews, focus group discussions, and key informant surveys. Secondary data were gathered from publications related to the topic from various institutions. The collected data were then analyzed using IBM SPSS V.26 and Microsoft Excel. Nearly all farmers in the study area kept Apis cerana bees, but due to insufficient irrigation, the crop fields provided limited forage for the bees during certain periods. The lowest number of frames covers by bees was four during the dearth period. Farmers in the Lamjung district did not practice migratory foraging. The majority of the respondents reported an increase in productivity compared to the previous year. However, only 37.1 percent of them cultivated bee flora. The colony carrying capacity of the forage area was not estimated. Additionally, an increase in deforestation was identified as the major problem affecting bee foraging. To address these issues, it was recommended to plant and cultivate perennial trees such as butter trees (Vitellaria paradox), bottle brush (Callistemon speciosus), litchi (Litchi chinensis), sissoo (Dalbergia sissoo), and sunflower (Helianthus annus) with assured irrigation. This approach could ensure year-round forage availability and reduce the need for artificial feeding. The research aimed to explore the current status of honey bee flora and investigate major flora that could be introduced in the study area
Prenatal and perinatal risk factors for disability in a rural Nepali birth cohort
Background:
Improving newborn health remains a global health priority. Little however is known about the neurodevelopmental consequences for survivors of complications in pregnancy, labour and the neonatal period in in low-income countries outside of small selective and typically urban facility studies. We ask which antenatal, birth and neonatal factors are associated with disability in childhood in a large community birth cohort from rural Nepal.
Methods:
6436 infants were recruited during a cluster randomised control trial (RCT) of participatory women's groups (ISRCTN31137309), of whom 6075 survived beyond 28 days. At mean age of 11∙5 years (range 9.5–13.1), 4219 children (27% lost to follow-up) were available for disability screening which was conducted by face-to-face interview using the Module on Child Functioning and Disability produced by the Washington Group/UNICEF. Hypothesised risk factors for disability underwent multivariable regression modelling.
Findings:
Overall prevalence of disability was 7.4%. Maternal underweight (OR 1.44 (95% CI 1.01–2.08)), maternal cohabitation under 16 years of age (OR 1.50 (1.13–2.00)), standardised infant weight at 1 month (OR 0.82 (0.71–0.95)) and reported infant diarrhoea and vomiting in the first month (OR 2.48 (1.58–3.89)) were significantly associated with disability adjusted for trial allocation. The majority of hypothesised risk factors, including prematurity, were not significant.
Interpretation:
Proxies for early marriage and low birth weight and a measure of maternal undernutrition were associated with increased odds of disability. The lack of association of most other recognised risk factors for adverse outcome and disability may be due to survival bias
Constraining the PG 1553+113 binary hypothesis: interpreting a new, 22-year period
PG 1553+113 is a well-known blazar exhibiting evidence of a -year
quasi-periodic oscillation in radio, optical, X-ray, and -ray bands. We
present evidence of a new, longer oscillation of years in its
historical optical light curve covering 100 years of observation. On its own,
this -year period has a statistical significance of when
accounting for the look-elsewhere effect. However, the probability of both the
- and -year periods arising from noise is ().
The next peak of the 22-year oscillation should occur around July 2025. We find
that the 10:1 relation between these two periods can arise in a
plausible supermassive black hole binary model. Our interpretation of PG
1553+113's two periods suggests that the binary engine has a mass ratio
, an eccentricity , and accretes from a disk with
characteristic aspect ratio . The putative supermassive black hole
binary radiates nHz gravitational waves, but the amplitude is
times too low for detection by foreseeable pulsar timing arrays.Comment: 18 pages, 13 figures, 1 tabl
Aptamer-Phage Reporters for Ultrasensitive Lateral Flow Assays
We introduce the modification of bacteriophage particles with aptamers for use as bioanalytical reporters, and demonstrate the use of these particles in ultrasensitive lateral flow assays. M13 phage displaying an in vivo biotinylatable peptide (AviTag) genetically fused to the phage tail protein pIII were used as reporter particle scaffolds, with biotinylated aptamers attached via avidin朾iotin linkages, and horseradish peroxidase (HRP) reporter enzymes covalently attached to the pVIII coat protein. These modified viral nanoparticles were used in immunochromatographic sandwich assays for the direct detection of IgE and of the penicillin-binding protein from Staphylococcus aureus (PBP2a). We also developed an additional lateral flow assay for IgE, in which the analyte is sandwiched between immobilized anti-IgE antibodies and aptamer-bearing reporter phage modified with HRP. The limit of detection of this LFA was 0.13 ng/mL IgE, ?100 times lower than those of previously reported IgE assays
Long-term impact of community-based participatory women's groups on child and maternal mortality and child disability: follow-up of a cluster randomised trial in rural Nepal
Background: Community-based women's groups practising participatory learning and action (PLA) can reduce maternal and neonatal mortality in low-income countries. However, it is not clear whether these reductions are associated with subsequent increased or decreased rates of childhood death and disability. We assessed the impact on child deaths and disability beyond the perinatal period among participants in the earliest trial in Nepal 2001-2003. Methods: Household interviews were conducted with mothers or household heads. At cluster and individual levels, we analysed disability using pairwise log relative risks and survival using multilevel logistic models. Findings: From 6075 children and 6117 mothers alive at 4 weeks post partum, 44 419 children (73%) were available for interview a mean 11.5 years later. Rates of child deaths beyond the perinatal period were 36.6 and 52.0 per 1000 children in the intervention and control arms respectively. Rates of disability were 62.7 and 85.5 per 1000 children in the intervention and control arms respectively. Individual-level analysis, including random effects for cluster pairing and adjusted for baseline maternal literacy, socioeconomic status and maternal age, showed lower, statistically non-significant, odds of child deaths (OR 0.70 (95% CI 0.43 to 1.18) and disability (0.64 (0.39 to 1.06)) in the intervention arm. Conclusion: Community-level exposure to women's groups practising PLA did not significantly impact childhood death or disability or death beyond the perinatal period. Follow-up of other trials with larger sample sizes is warranted in order to explore the possibility of potential long-term survival and disability benefits with greater precision
Speciated online PM1 from South Asian combustion sources-Part 1: Fuel-based emission factors and size distributions
Combustion of biomass, garbage, and fossil fuels in South Asia has led to poor air quality in the region and has uncertain climate forcing impacts. Online measurements of submicron aerosol (PM1) emissions were conducted as part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) to investigate and report emission factors (EFs) and vacuum aerodynamic diameter (dva) size distributions from prevalent but poorly characterized combustion sources. The online aerosol instrumentation included a qmini aerosol mass spectrometer (mAMS) and a dual-spot eight-channel aethalometer (AE33). The mAMS measured non-refractory PM1 mass, composition, and size. The AE33-measured black carbon (BC) mass and estimated light absorption at 370 nm due to organic aerosol or brown carbon. Complementary gas-phase measurements of carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) were collected using a Picarro Inc. cavity ring-down spectrometer (CRDS) to calculate fuel-based EFs using the carbon mass balance approach. The investigated emission sources include open garbage burning, diesel-powered irrigation pumps, idling motorcycles, traditional cookstoves fueled with dung and wood, agricultural residue fires, and coal-fired brick-making kilns, all of which were tested in the field. Open-garbage-burning emissions, which included mixed refuse and segregated plastics, were found to have some of the largest PM1 EFs (3.77-19.8 g k-1) and the highest variability of the investigated emission sources. Non-refractory organic aerosol (OA) size distributions measured by the mAMS from garbage-burning emissions were observed to have lognormal mode dva values ranging from 145 to 380 nm. Particle-phase hydrogen chloride (HCl) was observed from open garbage burning and was attributed to the burning of chlorinated plastics. Emissions from two diesel-powered irrigation pumps with different operational ages were tested during NAMaSTE. Organic aerosol and BC were the primary components of the emissions and the OA size distributions were centered at ∼ 80 nm dva. The older pump was observed to have significantly larger EFOA than the newer pump (5.18 g k-1 compared to 0.45 g k-1) and similar EFBC. Emissions from two distinct types of coal-fired brick-making kilns were investigated. The less advanced, intermittently fired clamp kiln was observed to have relatively large EFs of inorganic aerosol, including sulfate (0.48 g k-1) and ammonium (0.17 g k-1), compared to the other investigated emission sources. The clamp kiln was also observed to have the largest absorption Ångström exponent (AAE Combining double low line 4) and organic carbon (OC) to BC ratio (OC: BC Combining double low line 52). The continuously fired zigzag kiln was observed to have the largest fraction of sulfate emissions with an EFSO4 of 0.96 g k-1. Non-refractory aerosol size distributions for the brick kilns were centered at ∼ 400 nm dva. The biomass burning samples were all observed to have significant fractions of OA and non-refractory chloride; based on the size distribution results, the chloride was mostly externally mixed from the OA. The dung-fueled traditional cookstoves were observed to emit ammonium, suggesting that the chloride emissions were partially neutralized. In addition to reporting EFs and size distributions, aerosol optical properties and mass ratios of OC to BC were investigated to make comparisons with other NAMaSTE results (i.e., online photoacoustic extinctiometer (PAX) and off-line filter based) and the existing literature. This work provides critical field measurements of aerosol emissions from important yet under-characterized combustion sources common to South Asia and the developing world
Ambient air quality in the Kathmandu Valley, Nepal, during the pre-monsoon: Concentrations and sources of particulate matter and trace gases
The Kathmandu Valley in Nepal is a bowl-shaped urban basin that experiences severe air pollution that poses health risks to its 3.5 million inhabitants. As part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE), ambient air quality in the Kathmandu Valley was investigated from 11 to 24 April 2015, during the premonsoon season. Ambient concentrations of fine and coarse particulate matter (PM2:5 and PM10, respectively), online PM1, inorganic trace gases (NH3, HNO3, SO2, and HCl), and carbon-containing gases (CO2, CO, CH4, and 93 nonmethane volatile organic compounds; NMVOCs) were quantified at a semi-urban location near the center of the valley. Concentrations and ratios of NMVOC indicated origins primarily from poorly maintained vehicle emissions, biomass burning, and solvent/gasoline evaporation. During those 2 weeks, daily average PM2:5 concentrations ranged from 30 to 207 μ g m-3, which exceeded the World Health Organization 24 h guideline by factors of 1.2 to 8.3. On average, the nonwater mass of PM2:5 was composed of organic matter (48 %), elemental carbon (13 %), sulfate (16 %), nitrate (4 %), ammonium (9 %), chloride (2 %), calcium (1 %), magnesium (0.05 %), and potassium (1 %). Large diurnal variability in temperature and relative humidity drove corresponding variability in aerosol liquid water content, the gas-aerosol phase partitioning of NH3, HNO3, and HCl, and aerosol solution pH. The observed levels of gas-phase halogens suggest that multiphase halogen-radical chemistry involving both Cl and Br impacted regional air quality. To gain insight into the origins of organic carbon (OC), molecular markers for primary and secondary sources were quantified. Levoglucosan (averaging 1230±1154 ng m-3), 1,3,5-triphenylbenzene (0:8± 0:6 ng m-3), cholesterol (2:9±6:6 ng m-3), stigmastanol (1.0 ±0:8 ng m-3), and cis-pinonic acid (4:5 ± 1:9 ng m-3) indicate contributions from biomass burning, garbage burning, food cooking, cow dung burning, and monoterpene secondary organic aerosol, respectively. Drawing on source profiles developed in NAMaSTE, chemical mass balance (CMB) source apportionment modeling was used to estimate contributions to OC from major primary sources including garbage burning (18 ± 5 %), biomass burning (17 ± 10 %) inclusive of open burning and biomass-fueled cooking stoves, and internal-combustion (gasoline and diesel) engines (18±9 %). Model sensitivity tests with newly developed source profiles indicated contributions from biomass burning within a factor of 2 of previous estimates but greater contributions from garbage burning (up to three times), indicating large potential impacts of garbage burning on regional air quality and the need for further evaluation of this source. Contributions of secondary organic carbon (SOC) to PM2:5 OC included those originating from anthropogenic precursors such as naphthalene (10 ± 4 %) and methylnaphthalene (0:3 ± 0:1 %) and biogenic precursors for monoterpenes (0:13 ± 0:07 %) and sesquiterpenes (5 ± 2 %). An average of 25 % of the PM2.5 OC was unapportioned, indicating the presence of additional sources (e.g., evaporative and/or industrial emissions such as brick kilns, food cooking, and other types of SOC) and/or underestimation of the contributions from the identified source types. The source apportionment results indicate that anthropogenic combustion sources (including biomass burning, garbage burning, and fossil fuel combustion) were the greatest contributors to PM2:5 and, as such, should be considered primary targets for controlling ambient PM pollution
Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of trace gases and light-absorbing carbon from wood and dung cooking fires, garbage and crop residue burning, brick kilns, and other sources
The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in and around the Kathmandu Valley and in the Indo-Gangetic Plain (IGP) of southern Nepal during April 2015. The source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread in the developing world such as cooking with a variety of stoves and solid fuels, brick kilns, open burning of municipal solid waste (a.k.a. trash or garbage burning), crop residue burning, generators, irrigation pumps, and motorcycles. NAMaSTE produced the first, or rare, measurements of aerosol optical properties, aerosol mass, and detailed trace gas chemistry for the emissions from many of the sources. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared (FTIR) spectroscopy, whole-air sampling (WAS), and photoacoustic extinctiometers (PAX; 405 and 870nm) based on field work with a moveable lab sampling authentic sources. The primary aerosol optical properties reported include emission factors (EFs) for scattering and absorption coefficients (EF Bscat, EF Babs, inm2kg-1 fuel burned), single scattering albedos (SSAs), and absorption Ångström exponents (AAEs). From these data we estimate black and brown carbon (BC, BrC) emission factors (gkg-1 fuel burned). The trace gas measurements provide EFs (gkg-1) for CO2, CO, CH4, selected non-methane hydrocarbons up to C10, a large suite of oxygenated organic compounds, NH3, HCN, NOx, SO2, HCl, HF, etc. (up to ∼ 80 gases in all). The emissions varied significantly by source, and light absorption by both BrC and BC was important for many sources. The AAE for dung-fuel cooking fires (4.63±0.68) was significantly higher than for wood-fuel cooking fires (3.01±0.10). Dung-fuel cooking fires also emitted high levels of NH3 (3.00±1.33gkg-1), organic acids (7.66±6.90gkg-1), and HCN (2.01±1.25gkg-1), where the latter could contribute to satellite observations of high levels of HCN in the lower stratosphere above the Asian monsoon. HCN was also emitted in significant quantities by several non-biomass burning sources. BTEX compounds (benzene, toluene, ethylbenzene, xylenes) were major emissions from both dung- (∼4.5gkg-1) and wood-fuel (∼1.5gkg-1) cooking fires, and a simple method to estimate indoor exposure to the many measured important air toxics is described. Biogas emerged as the cleanest cooking technology of approximately a dozen stove-fuel combinations measured. Crop residue burning produced relatively high emissions of oxygenated organic compounds (∼12gkg-1) and SO2 (2.54±1.09gkg-1). Two brick kilns co-firing different amounts of biomass with coal as the primary fuel produced contrasting results. A zigzag kiln burning mostly coal at high efficiency produced larger amounts of BC, HF, HCl, and NOx, with the halogenated emissions likely coming from the clay. The clamp kiln (with relatively more biomass fuel) produced much greater quantities of most individual organic gases, about twice as much BrC, and significantly more known and likely organic aerosol precursors. Both kilns were significant SO2 sources with their emission factors averaging 12.8±0.2gkg-1. Mixed-garbage burning produced significantly more BC (3.3±3.88gkg-1) and BTEX (∼4.5gkg-1) emissions than in previous measurements. For all fossil fuel sources, diesel burned more efficiently than gasoline but produced larger NOx and aerosol emission factors. Among the least efficient sources sampled were gasoline-fueled motorcycles during start-up and idling for which the CO EF was on the order of ∼700gkg-1 - or about 10 times that of a typical biomass fire. Minor motorcycle servicing led to minimal if any reduction in gaseous pollutants but reduced particulate emissions, as detailed in a companion paper (Jayarathne et al., 2016). A small gasoline-powered generator and an insect repellent fire were also among the sources with the highest emission factors for pollutants. These measurements begin to address the critical data gap for these important, undersampled sources, but due to their diversity and abundance, more work is needed
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