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41 result(s) for "Sujan Khadka"
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Comprehensive evaluation of chemical properties and toxic metals in the surface water of Louhajang River, Bangladesh
Louhajang River, Bangladesh, which crosses Tangail as a densely industrialized and urbanized city, supplies water for different purposes. This study reports the levels of pH, electrical conductivity (EC), and some toxic heavy metals in 40 water samples collected during the summer and winter seasons from Louhajang River. The winter season reported higher levels of the examined parameters than the summer season with significant variation ( p < 0.05) for all parameters, with the exception of Cd. The metal contents were assessed against local and international standards for drinking, irrigation, and aquatic life purposes where different trends were observed. The heavy metal evaluation index and the ecological risk index reported low to moderate risks. The spatial distribution of metal contents assigned hot spots in some sites along the riverbed. The health risk assessment for three population categories, i.e., adult male, adult female, and children, was examined. Cr and Cd recorded hazard index > 1 in all cases, indicating possible non-cancer risk. The total carcinogenic risk values during both seasons were > 1.0 × 10 −6 , indicating possible cancer risk. The adopted collection of different approaches (comparison against standard levels of toxicants, statistical analysis, spatial distribution, and health risk assessment) successfully demonstrates a whole picture of the environmental status of Louhajang River, Bangladesh.
Multi-drug resistant extended-spectrum beta-lactamase producing E. coli and Salmonella on raw vegetable salads served at hotels and restaurants in Bharatpur, Nepal
Objective Antimicrobial resistance among the bacteria present in ready-to-eat foods like vegetable salads is an emerging concern today. The current study was undertaken to investigate the presence of multi-drug resistant extended-spectrum β-lactamase (ESBL) producing E. coli and Salmonella spp. in raw vegetable salads served at hotels and restaurants in Bharatpur. A total of 216 salad samples were collected from three different grades of hotels and restaurants and examined for the presence of E. coli and Salmonella spp. in Microbiology laboratory of Birendra Multiple Campus by conventional microbiological techniques. Results Out of 216 samples, 66 samples (35.2%) showed the presence of Salmonella spp. whereas E. coli was recovered from 29 (13.4%) samples of which 3 samples harbored E. coli O157: H7. Antibiotic susceptibility testing revealed that 9 (13.6%) Salmonella and 4 (13.8%) E. coli isolates were detected as multi-drug resistant. Total ESBL producers reported were 5 (7.57%) Salmonella and 4 (13.8%) E. coli . The study also assessed a significant association between occurrence of E. coli and Salmonella with different grades of hotels and restaurants, personal hygiene and literacy rate of chefs and with the type of cleaning materials used to wash knives and chopping boards (p < 0.05). The findings suggest an immediate need of attention by the concerned authorities to prevent the emergence and transmission of food-borne pathogens and infections antimicrobial resistance among them.
Bioactive Effects of Curcumin in Human Immunodeficiency Virus Infection Along with the Most Effective Isolation Techniques and Type of Nanoformulations
Human immunodeficiency virus (HIV) is one of the leading causes of death worldwide, with African countries being the worst affected by this deadly virus. Curcumin (CUR) is a Curcuma longa-derived polyphenol that has attracted the attention of researchers due to its antimicrobial, anti-inflammatory, antioxidant, immunomodulatory and antiviral effects. CUR also demonstrates anti-HIV effects by acting as a possible inhibitor of gp120 binding, integrase, protease, and topoisomerase II activities, besides also exerting a protective action against HIV-associated diseases. However, its effectiveness is limited due to its poor water solubility, rapid metabolism, and systemic elimination. Nanoformulations have been shown to be useful to enhance curcumin's bioavailability and its effectiveness as an anti-HIV agent. In this sense, bioactive effects of CUR in HIV infection are carefully reviewed, along with the most effective isolation techniques and type of nanoformulations available. Keywords: curcumin, bioactivities, HIV therapy, nanoparticles, nanoformulations
Investigation of trace metals in riverine waterways of Bangladesh using multivariate analyses: spatial toxicity variation and potential health risk assessment
Minute quantities of trace metals have delirious effects in the human body causing acute and chronic toxicities. These trace metals have the ability to bind with enzymes and proteins causing an alteration in their activity, and, consequently, their damage. In this study, water samples were collected from five sites in Rupsa River (Bangladesh) during dry and wet seasons aiming to assess the trace metal concentration and the correlated health risk for people living in the area. Six trace metals, namely arsenic (Ar), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and nickel (Ni), were measured for further analyzing their spatial and seasonal variations. The measured trace metal concentrations followed this decreasing order: Cr > Pb > As > Cu > Ni > Cd for the dry season, and Cr > Pb > As > Cu > Ni > Cd for the wet season. Among the trace metals, As, Ni, Cr, and Pb exhibited a statistically significative variation throughout the study period. The PCA analysis accounted for 64.5% and 64.4% total variations of the trace metals in dry and wet seasons, respectively. The Euclidean distance of trace metals in water samples across five sites showed significantly different distribution patterns, which were further confirmed by PERMANOVA. Furthermore, CAP model disclosed that trace metals are source-specific: brickfields and sewage effluents were potential sources for Cd, whereas different industries were potential sources for As, Cr, Cu, Ni, and Pb. Correlation analysis showed that Ni and Cr significantly correlated with pH and electrical conductivity. Correlation among the trace metals unveiled that they depended on each other as for their origin, magnitude, and existence in the riverine waterways. As for the health risk assessment, a non-carcinogenic health hazard due to ingestion during regular activities and dermal contact during fishing activity to all kind of people (adult males, adult females, and children) in the studied area was retrieved based on the hazard index (HI) of trace metals, which was higher than the recommended value (HI > 1). Moreover, also the carcinogenic risks of Ni and As due to regular activities via ingestion and dermal contact pathways were higher than the standard value (CR > 1.0E−04), suggesting the occurrence of cancer risk to humans in the study area.
A Comparative Study of Mathematical Methods for Determining Colding’s Constants for Milling of Steels and Experimental Validation
The optimization of cutting parameters is critical for improving machining efficiency and extending tool life. Colding’s equation is one such tool life prediction equation that can be used to optimize the machining parameters. However, the equation is complex and is often challenging to solve to evaluate its mathematical constants. This study investigates three distinct approaches for calculating the five constants (‘K’, ‘H’, ‘M’, ‘N0’, and ‘L’) in Colding’s equation. These techniques include analytical equation calculation and different curve fitting approaches. The primary objective was to assess the accuracy and effectiveness of these methods in predicting cutting parameters. Two workpiece materials, K1045 and Mild Steel, were used with results indicating that the Python 3.13 programming approach outperformed the other methods, including MATLAB R2024b and analytical calculations, achieving error percentages of 9.08% for K1045 and 5.51% for Mild Steel compared to 12.3% and 35.3% for K1045 and 12.4% and 64.3% for Mild Steel, respectively. Furthermore, the constants ‘N0’, ‘M’, and ‘H’ displayed different values for the two materials, indicating their dependence on workpiece material properties. Moreover, it was evident that Mild Steel exhibited better machinability than K1045 at low MRR (40–80 cm3/min), with up to 55.8% longer tool life, but K1045 performed better at medium and high MRRs, suggesting different machinability behaviours under varying cutting conditions. Overall, the findings demonstrate that Colding’s model, when applied with the appropriate computational method, can accurately optimize cutting parameters for different materials, contributing to more efficient and cost-effective machining processes.
Wolbachia: a possible weapon for controlling dengue in Nepal
Dengue, a mosquito-borne viral infectious disease, causes a high morbidity and mortality in tropical and subtropical areas of the world. In Nepal, the first case of dengue was reported in 2004 followed by frequent outbreaks in subsequent years, with the largest being in 2019 taking the death toll of six. It is reported that the number of dengue fever cases are soaring in Nepal spreading from the plains to more hilly regions. This might have serious public health implications in the future when combined with other factors, such as: global warming, lack of early detection and treatment of dengue, lack of diagnostic facilities, poor healthcare systems and mosquito control strategies. Nepal, thus, needs a cost-effective mosquito control strategy for the prevention and control of dengue. The Wolbachia -mediated biological method of the dengue control strategy is novel, economic, and environment-friendly. It has been successfully trialed in several areas of dengue-prone countries of the world, including Australia, Malaysia, Vietnam etc. resulting in significant reductions in dengue incidence. Given the lack of effective vector control strategy and weak economic condition of the country along with the persistence of climate and environment conditions that favors the host ( Aedes mosquito) for Wolbachia , this approach can be a promising option to control dengue in Nepal.
Study on biodegradation kinetics of di-2-ethylhexyl phthalate by newly isolated halotolerant Ochrobactrum anthropi strain L1-W
Objective Di-2-ethylhexyl phthalate (DEHP) pollution is one of the major environmental concerns all over the world. This research aimed at studying the biodegradation kinetics of DEHP by a newly isolated bacterial strain. Water and sediment samples were collected from Wuhan South Lake and potent bacterial isolates were screened for DEHP degradation, characterized by biochemical, physiological, morphological and 16S rDNA gene sequencing, and optimized under suitable pH, temperature, NaCl and DEHP concentrations. DEHP and its metabolites were quantified by High Performance Liquid Chromatography and their degradation kinetics were studied. Results The newly isolated bacterium was identified as Ochrobactrum anthropi strain L1-W with 99.63% similarity to Ochrobactrum anthropi ATCC 49188. It was capable of utilizing DEHP as the carbon source. The optimum growth temperature, pH, DEHP and NaCl concentration for the strain L1-W were 30 °C, 6, 400 mg/L and 10 g/L respectively. Strain L1-W was capable of degrading almost all (98.7%) of DEHP when the initial concentration was 200 mg/L within a period of 72 h. Besides, it was also found capable of degrading five other phthalates, thus making it a possible candidate for bioremediation of phthalates in the environmental settings.
Screening and Optimization of Newly Isolated Thermotolerant Lysinibacillus fusiformis Strain SK for Protease and Antifungal Activity
The current study was designed to isolate, identify and characterize a Bacillus sp. capable of producing protease and exhibiting antifungal activity. A highly potent bacterium capable of producing protease abundantly was isolated from the soil collected from the waste pit near Microbiology Laboratory of Birendra Multiple Campus, Bharatpur and later on identified as Lysinibacillus fusiformis strain SK on the basis of morphological, physiological, biochemical and 16S rDNA gene sequencing techniques. The strain SK showed 98.36% similarity with L. fusiformis strain NBRC 15717. Using R-programming statistical analysis tool, the optimum incubation time for the highest average protease production (APP) (47.2 U/mL) was found to be 22 h at 50 °C and both incubation time and temperature showed a significant impact on the production of protease (P < 0.01). The maximum average relative protease activity (ARPA) was observed at pH 7.8 and 48 °C, whereas the least ARPA was observed in the presence of 80 g/L NaCl and 10 g/L HgCl2 (P  < 0.01). The newly isolated bacterial strain also exhibited strong antifungal activity against aflatoxigenic Aspergillus flavus and Aspergillus parasiticus suggesting that it can be a potential candidate for protease production and activity over a wider range of temperature and pH as well as for synthesizing effective antifungal compounds.
Bacterial etiology of sputum from tuberculosis suspected patients and antibiogram of the isolates
Objective The current study aims to explore the bacteriology of sputum of tuberculosis (TB) suspected patients. A cross-sectional study was carried out in the sputum samples of 150 TB suspected patients visiting District Public Health Office, Bharatpur, Nepal. The samples were subjected to cultural, microscopic and biochemical analyses for the identification of the isolates. In addition, antibiotic susceptibility tests were carried out with a special focus on ESBL and MBL production following Clinical and Laboratory Standard Institute guidelines. Results Bacterial growth was recovered in 47% (71/150) of the TB suspected patients of which 12.66% (19/150) had pulmonary TB infection. Streptococcus spp. (9%) and Pseudomonas aeruginosa (9%) were the most frequently isolated bacteria. Enterobacteriaceae accounted for 35% of the total isolates. Occurrence of bacterial pathogens was more in males (69%) than in females (31%).The incidence of bacterial pathogen was seen associated with gender of the patients and with the TB infection (p < 0.05) but independent with age of the patients and HIV infection (p > 0.05). Tetracycline was effective against Streptococcus spp. whereas gentamicin was effective against Bacillus species. Imipenem and co-trimoxazole were effective drugs for Gram-negative isolates. Among 83 isolates, 35 were multi-drug resistant, 9 were ESBL producers and 4 were MBL producers.
Microbial Diversity and Antibiotic Susceptibility Pattern of Bacteria Associated with Motorcycle Helmets
Background. Motorcycle helmets can serve as a potential vehicle for the transmission of pathogenic bacteria and fungi with serious health implications. The main aim of this study was to explore the microbial diversity associated with the motorcycle helmets and determine the antibiotic susceptibility profile of the bacterial isolates. Methods. A descriptive cross-sectional study was carried out among the teaching staffs of Birendra Multiple Campus, Bharatpur, Nepal. A total of 130 motorcycle helmets worn by the teaching staffs of the Birendra Multiple Campus, Bharatpur, were included in the study for microbiological investigations. Results. Of the total 130 motorcycle helmets analyzed, 392 bacteria and 346 fungi belonging to seven different genera were recovered. Staphylococcus aureus 89 (22.7%) was the predominant bacteria followed by S. epidermidis 77 (19.6%) and E. coli 54 (13.8%), whereas Aspergillus niger 67 (19.4%) was the predominant fungi followed by A. fumigatus 49 (14.2%). Antibiotic susceptibility test was performed by the disc diffusion method for all the bacterial isolates. Tetracycline, gentamycin, and cotrimoxazole were the most effective antibiotics for Gram-positive isolates, whereas Gram-negative isolates were sensitive towards imipenem and ciprofloxacin. Of the total bacterial isolates, 153 (39.0%) were multidrug-resistant (MDR), 10.4% were extended-spectrum beta-lactamase (ESBL) producers, and 4.3% were metallo-beta-lactamase (MBL) producers and, out of 89 isolates of Staphylococcus aureus, 30 (33.7%) were detected as methicillin-resistant Staphylococcus aureus (MRSA). Conclusion. The findings suggest that motorcycle riders should follow good hygiene practices and regularly clean their helmets with suitable sterilants to avoid the risk of microbial contamination and reduce the associated risks.