Nepal Journal of Science and Technology最新文献

{"title":"Stimulated Emission Depletion Microscopy Resolves Nanoparticle Assembly on a Porous Membrane Surface","authors":"B. Neupane","doi":"10.3126/NJST.V17I1.25058","DOIUrl":"https://doi.org/10.3126/NJST.V17I1.25058","url":null,"abstract":"Stimulated emission depletion microscopy—depending on the nature of fluorophore and sample, depletion laser power, and other experimental conditions—provides diffraction unlimited lateral resolution in the range of 20-100 nm. In this manuscript, a detailed description of such a microscope along with one of the possible imaging schemes is provided. Application of such a microscope in resolving self assembly of polymeric nanoparticles on porous alumina membrane in wet condition is demonstrated. STED microscopy resolves formation of loose linear to quasi polygonal self-assembly patterns on the membrane surface. Possible reasons for the formation of such self assembly patterns are provided","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127629045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water hardness removal using wheat straw and rice husk ash","authors":"Hari Lal Kharel","doi":"10.3126/NJST.V17I1.25057","DOIUrl":"https://doi.org/10.3126/NJST.V17I1.25057","url":null,"abstract":"This study examined potential of using wheat straw ash (WSA) and rice husk ash (RHA) to remove hardness of natural and synthetic water. Eight water samples (both natural and synthetic) with hardness between 236 to 580 mg/L were treated with eleven different doses of WSA and RHA ranged from 0 to 25 g ash L -1 at regular increment of 2.5 g. Water hardness, hardness removal efficiency and change in pH were measured. Hardness removal efficiency and pH of water increased with increasing doses of ash. Maximum removal was achieved at 17.5 and 22.5 g/L for WSA and RHA and further ash addition did not change the hardness. Maximum removal efficiency of WSA was 81% and RHA was 58%. Higher efficiency of WSA might be related to presence of higher concentrations of alkali metal oxide. As similar to removal efficiency, WSA also increased pH of water samples relative to RHA. The results thus indicate that locally available WSA and RHA may be an alternative technique in hardness removal process.","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129401258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis of Chitosan from Prawn Shells and Characterization of its Structural and Antimicrobial Properties","authors":"Shanta Pokhrel, R. Lach, W. Grellmann, A. Wutzler, W. Lebek, R. Godehardt, Paras Nath, Yadav, R. Adhikari","doi":"10.3126/NJST.V17I1.25056","DOIUrl":"https://doi.org/10.3126/NJST.V17I1.25056","url":null,"abstract":"Chitin was prepared from prawn shells waste by chemical treatments viz . demineralization, deproteinization and decolorization. Chitosan was prepared by deacetylation of chitin with 50% NaOH at 100 °C in the presence of nitrogen. Deacetylation was performed at different intervals of time to get a series of chitosans having different degrees of deacetylation. Prepared chitosans were characterized by molecular weight determination, degree of deacetylation, Fourier transform infrared (FTIR) spectroscopy and Scanning electron micrography (SEM). The degree of deacetylation of chitosans was calculated by acid base titration and potentiometric titration. The molecular weights of commercial and prepared chitosan (CS-4.0) samples were determined using the Mark-Houwink equation and were found to be 3.5 × 10 5 (g/mole) and 3.3 × 10 4 (g/mole), respectively. The degree of deacetylation was found to linearly increase with the increase of reaction time. FTIR spectra showed the characteristic peaks of chitin and chitosan. Antimicrobial screening results revealed that the prepared chitosan (CS-4.0) was equally or more biologically active than the commercial chitosan.","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132459681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and characterization of ZnTe nanoparticles","authors":"Sujan Dhungana, B. R. Poudel, S. K. Gautam","doi":"10.3126/NJST.V17I1.25054","DOIUrl":"https://doi.org/10.3126/NJST.V17I1.25054","url":null,"abstract":"In this work, we report the ZnTe semiconductor nanoparticles (NPs) prepared by aqueous chemical precipitation method using the tellurium precursor solution with different zinc compounds. Three batches of ZnTe NPs were synthesized to study the effect of dilution on the size and phase purity of ZnTe. The influence of source compounds and concentrations of the size and structure of NPs were studied. ZnTe NPs have great applications as field-effect transistors and photodetectors. The existing controversy regarding the crystalline structure of ZnTe NPs, whether it is cubic or hexagonal, has been resolved using X-ray Diffraction (XRD) data. The ZnTe NPs possess cubic structure, which is also confirmed by Electron Diffraction (ED) pattern. The average particle size determined from XRD data with the help of Debye-Scherrer equation is about 6 nm. The particle size can be further verified by Transmission Electron Microscopy (TEM) studies.","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123639360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crop Protection and Its Effectiveness against Wildlife: A Case Study of Two Villages of Shivapuri National Park, Nepal","authors":"S. Pandey, S. Bajracharya","doi":"10.3126/NJST.V16I1.14352","DOIUrl":"https://doi.org/10.3126/NJST.V16I1.14352","url":null,"abstract":"A complex relationship between the residents and protected areas continue to be an obstacle to successful conservation of protected areas. Conflicts between park authority and people living around the park pose a threat to conservation. Moreover, crop depredation due to wildlife incurs a severe economic loss to communities living in the close vicinity of the park, affecting the livelihood and well-being of locals. Many studies have been carried out emphasizing the identification and quantification of crop damage, but studies highlighting the means used for the crop protection and their effectiveness are limited. This paper examines frequency of the crop damage by wildlife and efficacy of utilized management practices in Shivapuri National Park (SNP). Altogether 132 households were visited in two buffer zone villages namely, Sikre and Jhor Mahankhal of Shivapuri National Park, Nepal. The study suggested that crop depredation by wildlife was a function of several factors, namely, distance of the farmland from the park, size of the crop raiding animals, frequency of their attacks on the farmland, and the type of crops. Five different measures were identified by the communities which they regularly used to prevent crop damage. Both traditional as well as modern means were used by households to guard crops from invading wild animals. The means of crop protection from wildlife differed according to the type of animal and crop being protected. Biofencing and trenches were effective for the small animals. Watch tower “Machans” and throwing flaming sticks and making noises were the most effective and safest means of crop guarding from all kind of animals. Though crop guarding was intensive, no means were found to be able to prevent crop damage completely. Thus, site specific management strategies as well as technical and financial support from donor organizations would be most useful to minimize crop loss. Nepal Journal of Science and Technology Vol. 16 , No.1 (2015) pp. 1-10","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131626303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal Variation of Rainfall in the Bagmati River Basin, Nepal","authors":"R. Shrestha, A. B. Sthapit","doi":"10.3126/NJST.V16I1.14355","DOIUrl":"https://doi.org/10.3126/NJST.V16I1.14355","url":null,"abstract":"The main aim of the study was to identify the temporal variation of rainfall in the Bagmati River basin, Nepal using  data available at Department of Hydrology and Meteorology, Government of Nepal. The time series data for the  period of 1981-2008 were analyzed by using non-parametric Mann-Kendal test, Spearman’s’ Rho and a parametric  linear regression. The results showed that there was a significantly increasing upward trend of the annual mean of  weighted areal rainfall, with a rate of 2.2 mm per year. Trend analysis of the monthly time series of weighted areal  rainfall showed a significant upward trend in the months of summer monsoon season (June and July). However,  there were no such significant result in the other season/months. The increasing trend in the summer monsoon  might lead to severe flooding in future. Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp. 31-40","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128081231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Species Diversity, Forest Community Structure and Regeneration in Banke National Park","authors":"R. Napit","doi":"10.3126/NJST.V16I1.14354","DOIUrl":"https://doi.org/10.3126/NJST.V16I1.14354","url":null,"abstract":"Banke national park, located in Banke district of western Nepal with an area of 550 sq. km was established as the  tenth national park in 2010 A.D. Forest community structure, species diversity and natural regeneration were  studied in the Park. A total of 1067 plots at every interval of 200m were laid by line transect method for the study. In  each plot three concentric rings of radii of 10m, 5m, and 1m were laid down for the study of trees, shrubs/saplings  and herbs/seedlings respectively. The park was floristically rich with a total of 113 species of trees representing 57  genera and 28 families. Similarly 85 species of shrubs including climbers and 107 species of herbs including  herbaceous climbers, and grasses were recorded. The obtained results from the size class distribution of the trees  resembling inverse ‘J’ shape indicated the good regenerating capability of the forest in the park. Fifty eight species  of saplings and 40 species of seedlings of trees were recorded. From the quantitative study of the trees, the  dominant species was Shorea robusta based on IVI (important value index) values, which was followed by Terminalia  alata , Anogeissus latifolius, Mallotus philippinensis, etc. The total density stand (D) and basal area (BA) of the  park were 291.48 trees/ha and 21.13 m 2 /ha respectively. The highest density (D) and the basal area (BA) of S.  robusta was 46.07 trees /ha and 5.07m 2 /ha respectively. The species diversity index (H) of the tree species in BaNP  was 1.32, with species evenness (J) of 0.64 and index of dominance (C) of 0.08. A total of seven forest community  types were estimated in the Park. The size class distribution diagram of all trees showed right skewed (inverse J  shaped) pattern indicating a good regenerating capability of the forest. The regeneration of S. robusta , T. alata and  A. latifolius were higher in comparison to other tree species which was indicated by the higher seedlings and  saplings density of them. S. robusta was the dominant with saplings density of 200.49 / ha and seedlings density  of 27153.4 /ha . Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp. 17-30","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122360610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beta Lactamase Producing Escherichia coli, Klebsiella pneumoniae and Methicillin Resistant Staphylococcus aureus among Uropathogens","authors":"Vivek Kumar Singh, R. Tuladhar, M. Chaudhary","doi":"10.3126/NJST.V16I1.14364","DOIUrl":"https://doi.org/10.3126/NJST.V16I1.14364","url":null,"abstract":"Urinary tract infection (UTI) is the leading cause of morbidity and health care expenditures in persons of all the ages. The impact of disease is high in the low-resource developing countries due to lack of awareness about the UTIs caused by extended spectrum beta lactamase producing pathogens and methicillin resistant Staphylococcus aureus . This study represents a cross-sectional analysis of UTI prevalence in patients attending at KIST Medical College Teaching Hospital, Imadole, Lalitpur. Bacterial isolates were identified using standard biochemical tests. The antimicrobial susceptibility to various drugs and confirmation of the extended spectrum s-lactamase (ESBL) and methicillin resistant Staphylococcus aureus (MRSA) production was done following Clinical & Laboratory Standards Institute (CLSI) guidelines. During the study period, 303 (24.08% of urine submissions) UTIs were confirmed. Among these 303 strains, E. coli was the most common, representing 65.34% of the isolates, followed by S. aureus (6.93%) and other pathogens (27.72%). Prevalence of ESBL E. coli, K. pneumoniae and MRSA in the urinary isolates were found to be 38.38 %, 35 % and 47.61 % respectively. Empiric treatment for UTIs in Nepal should be reconsidered and prudent use of antibiotics, particularly Gentamycin, is highly recommended. The recent spread of ESBL-producing Enterobacteriaceae and MRSA is striking and underlines the need for further studies. Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp. 105-112","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130781912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Plant Extracts against Stemphylium Blight of Lentil","authors":"S. Subedi, S. Shrestha, G. Kc, R. Thapa, S. Ghimire, D. Gharti, S. Neupane","doi":"10.3126/NJST.V16I1.14353","DOIUrl":"https://doi.org/10.3126/NJST.V16I1.14353","url":null,"abstract":"Experiments were carried out to evaluate five different plant extracts against lentil stemphylium blight ( Stemphylium botryosum Walr.) at the Grain Legume Research Program, Rampur, Chitwan, Nepal during two winter seasons (2011/ 12 and 2012/13) using CRD in laboratory and RCBD in field conditions. Water extract of Acorus calamus at higher dose (8% W/V) was able to check the growth of the pathogen completely in-vitro . The mycelial growth inhibition (%) of Xanthoxylum armatum and Lantana camera at 8% concentration in PDA were 31.17 and 24.56 respectively. In the field experiment during 2011/12, extracts were sparingly effective for a short period. However the disease control (PDC) was higher in X. armatum treated plot (31.60%) followed by A. calamaus (28.69%) and L. camera (27.61%) when compared to unsprayed plot. The following year (2012/13) field experimental results also verified the effect of plant extracts against the disease. The lower Disease (%) Index (PDI) was obtained from the plots treated with A. calamus (35.33%) and X. armatum (35.55%). Higher crop yield was recorded from the plot treated with A. calamus (987.39 kg/ha) followed by X. armatum (972.78 kg/ha). Two years’ experimental results revealed that A. calamus and X. armatum were effective botanicals to manage lentil Stemphylium blight. Nepal Journal of Science and Technology Vol. 16, No.1 (2015)  pp. 11-16","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127186859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate Change Dry Spell Impact on Agriculture in Salyantar, Dhading, Central Nepal","authors":"P. Paudyal, D. Bhuju, M. Aryal","doi":"10.3126/NJST.V16I1.14358","DOIUrl":"https://doi.org/10.3126/NJST.V16I1.14358","url":null,"abstract":"Understanding the problem increasingly posed by climatic change is one of the critical challenges of our time. A study was carried out in Salyantar village in Dhading district of central Nepal to understand and assess the extent of climate change impacts on agriculture. The impact assessment was performed through analysis of meteorological data, Landsat images, and people’s perception on changes relative to agriculture sector. Mann-Kendall statistical trend test was used to assign statistical significance to the trend whereas temperature vegetation dryness index (TVDI) was used to identify soil moisture condition as an assessment criterion. The perception of local people on climate change and its impacts was studied through generalized questionnaire survey and participatory rural appraisal. The results of the study portrayed rise in temperature in the study area in the recent years in comparison to the past. The maximum temperature increment was 0.03p C per year. As for precipitation, it showed decreasing trend by 1.855mm per year. The TVDI obtained from Landsat image, showed decreasing trend of soil moisture in different years, which indicate an increased longer dry spell. This has unswerving effect on agriculture as the entire Salyantar village is dependent upon rain-fed agriculture. The perceived impacts on agriculture were decreased crop yield, reduced soil moisture, and increased incidence of new pests and invasive plant species. Such impacts were fairly heterogeneous in distribution. The Salyantar village, a raised flat-land of river deposition already stuck in the grip of water stress, was found exacerbated by the effect of climate change. Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp.59-68","PeriodicalId":129302,"journal":{"name":"Nepal Journal of Science and Technology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130335844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}