Scientific World

Entropy of coupled Klein-Gorden Field in FLRW space

2023-07-18T06:29:52+00:00

The coupled Klein-Gordan (KG) field in FLRW space-time has been further studied to explore its effect on entropy. The modifications in pressure and density and hence entropy due to coupling have been calculated. There is an indication seen that the introduction of the coupling contributes to the generation of entropy in the KG field which may probably explain the large entropy of the universe.

Monitoring linear accelerator beam with daily quality assurance phantom

2023-07-18T07:29:22+00:00

This paper aims to analyze the output constancy of a medical linear accelerator using PTW, and to study the suitability as a daily quality assurance device. It is assumed that the device is sensitive enough to detect minor variations in central axis beam, flatness, symmetry, and beam quality factor. PTW, QUICKCHECK^webline is the most efficient wireless device used in daily quality assurance. The measurements of output doses of photons ( 6MV and 15 MV) and electrons (6,9,12, and 15MeV) from a medical linear accelerator before the daily treatment have been graphically analyzed. This study assures the output stability of Varian Clinac iX 2100 CD linear accelerator at Bhaktapur Cancer Hospital, Bhaktapur, Nepal. The beam flatness, symmetry, beam quality factor, and central axis of photon and electron beam have been analyzed for 10x10cm² and 20x20cm² field size in separate ways. Among the measurements, observed parameters lie under the tolerance limit as recommended by American Association of Physicists in Medicine viz. ±3%. The outcomes of the measurements are in the acceptable range for the treatment procedure of patients.

Monte-Carlo simulation of phase transition in 2D and 3D ising model

2023-07-18T07:51:19+00:00

In this work, Markov Chain-Monte Carlo technique was used to study the phase transition in two and three dimensional Ising Model (IM) in a square and cubic lattice. The study of temperature dependence of average magnetization and specific heat in different magnetic fields has been carried out in the 3x3 and 3x3x3 lattice with periodic boundary. Critical temperature point k_BT_c / J for 2D and 3D Ising Model has been observed at around 2.2 and 4.3 respectively at zero field. Our work satisfies Onsager’s critical value in 2D IM. The simulation suggests bifurcation in average magnetization below critical temperature T_c. Temperature plays the role of increasing randomness of spins. We found that Ising Model in small lattice size still retains interesting features like spontaneous magnetization and symmetry breaking below T_c at B = 0. At a non-zero field, the likelihood of spins to prefer certain alignment depends on the direction of the external field and magnitude of magnetization depends on magnitude of field ±B. Specific heat C_v, which gives us fluctuation of energy at particular temperature, has been found to attain maximum value at critical regions.

Distribution of dust color temperature, dust mass and planck’s function around C-rich AGB star: IRAS 19558+3333 using IRIS, AKARI, and WISE Surveys

2023-07-21T05:36:32+00:00

The dust properties of C-rich AGB (Asymptotic giant branch) star IRAS 19558+3333 located at right ascension (R.A.) (J2000) = 19^h 57^m 48.440^s and Declination (J2000) = +33⁰ 41^h 21.250^s was studied. The FITS image of this AGB star was obtained by SkyView Virtual Observatory in IRIS, AKARI, and WISE surveys respectively. The flux of ambient medium in the wavelength range of IRIS 60 μm and 100 μm, AKARI 90 μm and 140 μm and WISE 12 μm and 22 μm was calculated along with the physical properties like dust color temperature, dust mass, Planck’s function and visual extinction of the candidate at a distance of 3415.420 pc. The minimum and maximum dust mass is found to be 1.606× 10²¹ kg (8.030 × 10⁻¹⁰ M⊙), and 7.013 × 10²⁰ kg (3.506× 10⁻¹⁰ M⊙) in IRIS, 2.739 × 10²² kg (1.369× 10⁻⁸ M⊙), and 1.292 × 10²² kg (6.460 × 10^-9 M⊙) in AKARI and 2.297 × 10²⁰ kg (1.148 × 10⁻¹⁰ M⊙) and 3.013 × 10¹⁹ kg (1.506 × 10⁻¹¹ M⊙) in the WISE survey and the dust color temperature of the corresponding C-rich star average value was found to be 24.230 ± 0.229 K in IRIS, 16.780 ± 0.189 K in AKARI and 123.750 ± 0.430 K in WISE survey. The temperature in WISE was higher than that of the AKARI and WISE surveys.

Phytochemical and Biological Evaluation and Isolation of Quercetin from Hypericum cordifolium Flower

2023-07-19T04:37:25+00:00

Hypericum cordifolium is a medicinal plant used in the treatment of various ailments in Nepalese traditional medicine. The medicinal values and bioactive constituents of Hypericum perforatum have been well investigated and is used as an alternative medicine in the treatment of depression, cancer, inflammation, bacterial and viral infections. However, scientific reports on Nepalese H. cordifolium are very limited. Here we report about the chemical screening of extracts, quality analysis of H. cordifolium extract by thin layer chromatography, TLC using H. perforatum extract and hyperoside as the standards, estimation of phenolics, flavonoids, tannins and sugars as well as antioxidant, antibacterial and cytotoxic activities of flower extracts. The ethyl acetate extract was fractionated and some phytochemicals were isolated. In our findings, TLC analysis of H. cordifolium extract showed the presence of chlorogenic acid, hyperoside and quercetin. Hypericine and rutin were not detected which indicated that the chemotaxonomy of H. cordifolium is different from H. perforatum. In phytochemical analysis, ethyl acetate extract showed the greater amounts of flavonoids, methanol extract showed the greater amounts of tannins and sugars and 50% aqueous methanol extract showed the greater amounts of phenolics. In DPPH free radical scavenging assay, ethyl acetate (18.79±0.98 μg/ml) and 50% aq. methanol (18.98±0.81 μg/ml) extracts showed the lower IC₅₀ values than the methanol extract (27.00±1.03 μg/ml) due to the presence of high amounts of flavonoids and phenolics in these extracts. In antibacterial assay, all extracts showed moderate antibacterial activity against Staphylococcus aureus except 50% aqueous methanol extract. In cytotoxicity assay on human bladder carcinoma cell line 5637, ethanol extract showed IC₅₀ value of 41.35±5.01 μg/ ml. Quercetin was isolated from ethyl acetate extract and characterized by UV and FTIR spectroscopy. The present findings indicated that the flowers of H. cordifolium could be the rich source bioactive compounds with antibacterial, cytotoxic and antioxidant activities.

Incorporation of Fe(iii) into Bentonite and Study of its As3+ Adsorption Properties

2023-07-19T04:49:26+00:00

Bentonite is montmorillonite type layered clay and has high cation exchange capacity (CEC) because of its typical layered silicate structure. The bentonite was treated with hydrochloric acid to obtain H-bentonite which was further modified by incorporating Fe(Ⅲ) into it. The modified Fe-bentonite was characterized by XRD and FTIR analyses. The specific surface area of the Fe-bentonite adsorbent was obtained from Methylene Blue Adsorption Method and was 598 m²/g.

The adsorption of As³⁺ by Fe-bentonite adsorbent in aqueous environment was investigated by varying different experimental parameters such as pH, contact time and adsorption isotherm. The adsorption process was found to be best fitted to Langmuir adsorption isotherm model controlled by pseudo-second –order kinetics with the rate constant value 0.03723 g/(mg.min). The maximum arsenic adsorption was observed at pH 5 at room temperature. The time taken to reach equilibrium was 75 minutes. The maximum adsorption capacity for As³⁺ on Fe-bentonite was 101.01 mg/g. The value of ∆G (-21 kJ/mole) confirmed the adsorption process was favored by physiosorption. The slope of the linear plot of Q_t vs t^0.5 was linear but not passed through the origin, which indicated that, the intraparticle diffusion was not only rate controlling step.

Impact of thunderstorm activities on tropospheric NOx adversely affecting the climate change over Bagmati province of Nepal

2023-07-23T03:54:53+00:00

Lightning is a complex electrical discharge that occurs in the atmosphere. Huge currents associated with the lightning discharge raises the ambient temperature resulting in the change in atmospheric chemistry. The extreme temperatures within lightning channels break apart molecular nitrogen (N₂) and oxygen (O₂) to produce nitrogen oxides (NO_x). NOx act as indirect greenhouse gases by producing the tropospheric Ozone. Likewise, NOx gases also affect the global greenhouse gas budget through the change in concentration of hydroxyl radical (OH) and Methane. This study analyzes the association of lightning stroke density with the tropospheric NOx over the Bagmati province (central region) of Nepal, during pre-monsoon and post-monsoon for 3 years (2018 to 2020). The tropospheric NOx was examined by utilizing the data from Ozone Monitoring Instrument (OMI), whereas the lightning stroke data was obtained from VAISALA’s Global Lightning Detection (GLD-360) Network. The lightning stroke density for each season were plotted against the corresponding average value of NOx to obtain the correlation coefficient over the period of study. Strong positive correlations between lightning and NOx production during per-monsoon periods were obtained for all the three years of study period, whereas, comparatively weak correlations are obtained for the post-monsoon seasons. Nevertheless, the NOx production due to lightning is found to be strong, during the pre-monsoon period, a relatively dry season over the Bagmati province. This clearly indicates that lightning is a big source of tropospheric NOx,that in turn produces greenhouse gases and hence contributes to the climatic changes over the central region on Nepal.

Adsorptive removal of Cr (VI) from aqueous solution using laboratory prepared ZnO nanoparticles

2023-07-20T04:30:07+00:00

Nano sized zinc oxide (ZnO) been successfully prepared in laboratory by precipitation technique. As prepared ZnO materials were characterized by XRD and SEM analyses. The XRD pattern showed the crystallinity of the material and average crystallite size was found to be 16.61 nm. The SEM images of ZnO nanoparticle revealed that it was flakes like structure having smooth texture. Batch adsorption experiments were performed to investigate the percentage removal of Cr (VI) from aqueous solution. The effects of Cr (VI) concentration, pH of solution, adsorbent dose and contact time variations were studied in order to have adsorptive efficiency of as prepared ZnO nanoparticles. The optimum contact time for maximum adsorption was found to be 90 minutes. The optimum pH was found to be 2.0 at an initial concentration of 20 mg/L. Similarly, the optimum dose of ZnO for the adsorption of Cr (VI) was found to be 0.4 g. The adsorption properties of ZnO were then evaluated by using Langmuir, Freundlich and Temkin isotherm models. The maximum adsorption capacity (Q_m) was found to be 3.43 mg/g which is in good agreement with literature value. The correlation value showed that Langmuir isotherm model was found to be more favorable than Freundlich and Temkin adsorption isotherm model, indicating the presence of homogeneous equivalent active sites in ZnO with monolayer adsorption.

Analysis of phytochemical constituent and biological significance of rhododendrons collected from capital of Laliguras, Laliguras municipality, Tehrathum district, Nepal

2023-07-20T04:39:46+00:00

The largest genus of the Ericaceae family, Rhododendron includes an inspiring number of species. Some of which have been used in the treatment of various ailments such as diseases associated with heart, dysentery, diarrhea, detoxification, fever, constipation, bronchitis and asthma around the world including Nepal. However, systematic study on phytochemistry and pharmacology of Rhododendrons grown in the Capital of Laliguras, Laliguras Municipality, Tehrathum of Nepal is lacking. So this study was conducted to evaluate the antioxidant activity, α-amylase inhibition activity, total phenolic and flavonoid contents of Rhododendron arboretum and Rhododendron campanulatum from Laliguras Municipality, Tehrathum of Nepal. Plant extracts were prepared in methanol by cold percolation method. Phytochemical constituents were analyzed by following standard methods. Antioxidant activity was measured through 2, 2-Diphenyl-1-Picrylhydrazyl assay. Total phenolic and flavonoid content were estimated using Folin–Ciocalteau and aluminum chloride method respectively. Alpha amylase inhibition assay was carried out by starch iodine method. Phytochemical screening of methanolic extract of flower and leaf of R. arboretum and leaves of R. campanulatum displayed the presence of different chemical constituents such as flavonoids, polyphenols, terpenoids, saponins and quinins. Samples showed dose-dependent radical scavenging and α-amylase inhibition activity. Radical scavenging activity and α-amylase inhibition activity of the methanolic extracts of different parts of R. arboretum and R. campanulatum ranged from 19.46 to 95.88% and 13.23 to 68.44% respectively. Flower extracts of R. arboreum showing the strongest radical scavenging activity and α-amylase inhibition with IC₅₀ values 33.61 and 443.44 μg/mL respectively. Among the tested samples, flower extract of R. arboretum showed the strongest antioxidant activity, alpha amylase inhibition activity and contained the highest amount of total phenolic and flavonoid content.

Study on quality parameters of wine at opening and deterioration with time

2023-07-20T09:39:06+00:00

Wine is an alcoholic beverage made from grapes containing alcohol ranging from 5-15% by volume. Wine consumption in the Nepalese market is gaining steady growth in recent years. In this study, parameters such as specific gravity, total acidity, pH, percentage of alcohol content, amount of total dissolved solid, presence of furfural, methyl alcohol and heavy metal were selected for analysis of red and white wine with time after the opening of the packet wine at the time interval of 15, 20 and 25 days respectively.

An increase in acidity and specific gravity (0.9780-0.9992 g/mL) while decrease in alcohol content (9.54%-8.03% by volume), presence of heavy Iron and Copper found below 0.003 and absence of furfural and methyl alcohol were observed with time. Consumption of wine in controlled amounts could prevent heart disease and circulatory problem. However, excess wine consumption can inhibit new brain cell development and depressive disorders.

Isolation and identification of Bacillus species from soil and assessment of antimicrobial properties

2023-07-20T09:56:37+00:00

The emergence of multi drug resistant pathogens such as Methicillin resistant Staphylococcus aureus (MRSA) has become a threat to public health. Thus, the development of new antibiotics has become a global concern. Many scientists are attracted towards discovery of new antimicrobial agents from microbial sources. The aim of this study is to isolate potential Bacillus species from soil for the production of antimicrobial substance. During the study, 20 soil samples were collected from various areas of Kathmandu valley. A total of 70 Bacillus isolates were identified by morphological and biochemical characteristics. Altogether 39 isolates were able to produce antibacterial extract when it was grown in Trypticase soya broth (TSB) at 37°C for 48 h. The antimicrobial activity was tested against test organisms like Escherichia coli, Klebsiella pneumoniae, Salmonella, Pseudomonas, Staphylococcus aureus and Candida by Agar well diffusion method. All of the extracts showed zone of inhibition against E. coli except 6 extracts (E39, E43, E36, E25, E45 and E46). The highest zone of inhibition was shown by extract B68 with 11 mm. Only one extract (E62) was able to inhibit the growth of Pseudomonas. The extract from Bacillus isolate (E35) showed highest zone of inhibition against S. aureus (6mm). The protein nature of the extracts was determined by Biuret and Ninhydrin tests. The extracts were relatively stable to heat treatment and unstable to surfactants like 70% methanol, 2-propanol and ethylacetate. The study revealed that soil is a good source for the potential antimicrobial producer bacteria.

Water quality and health risk assessment in the Gandaki river basin, central Himalaya, Nepal

2023-07-21T03:40:47+00:00

Public health is at threat due to chemical contaminants in drinking water which may have direct health concerns. The suitability of water for health is primarily governed by the mineral constituents present in the water. The present study was carried out to evaluate the water quality and associated health risks in the Gandaki River Basin (GRB) in Central Himalaya, Nepal considering hydrochemical variables such as total dissolved solids (TDS); major cations (Ca²⁺, Mg²⁺, K⁺, and Na⁺); major anions (Cl^-, NO₃^-, SO₄^2-, and HCO₃^-) and trace metals (As, Cu, Mn, Ni, Pb, Zn, Ba, Cr, Li and Sr) in spatiotemporal levels. Water Quality Index (WQI), Health Risk Assessment (HRA), and Cancer Index (CI) were analyzed to evaluate the overall quality of water in the GRB. The results revealed that all the examined variables were within the National Guidelines recommended for domestic uses. Moreover, the results revealed that concentrations of TDS, major ions, and trace metals showed significant seasonality and the WQI values were found to be 36.38, 23.77, and 30.36 in pre-monsoon, monsoon, and post-monsoon, respectively indicating better water quality in the monsoon season. Additionally, CI analysis of the selected trace metals such as As, Cr and Pb indicated relatively low cancer risk in the river water during all the seasons. The hazard quotient (HQ) dermal values of all the elements were < 1, signifying the little or no adverse effects via a dermal path, while HQ ingestion values of Ba, Li, Sr, and Zn were found to be >1 during all the seasons indicating their possible threat via ingestion path. This study provides a useful database and suggests regular assessment and, also appropriate policy formulations for safeguarding the water bodies in the Himalayas.

Lampblack of soybean oil as a low-cost electrode material in supercapacitor application

2023-07-21T04:01:30+00:00

Lampblack of soybean oil was investigated as a potential low-cost material to make electrodes of supercapacitors. The lampblack carbon was characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The electrochemical performance of the lampblack carbon electrode was tested using a three-electrode system, where a platinum wire was used as a counter electrode, a carbon electrode as a working electrode, and Ag/AgCl electrode as a reference electrode. The experiments, Galvanostatic Charge-Discharge (GCD) and Cyclic Voltammetry (CV) were performed in 3M aq. KOH. The specific capacitance of the lampblack carbon electrode from GCD was found to be 49.27 F g^-1 at 1 A g^-1. The lampblack carbon electrode showed good capacitive behavior at both low and high scan rates. The results indicated that lampblack carbon of soybean oil can be a new efficient alternative material for low-cost high-performance supercapacitors.

Phytochemical analysis of Schizophyllum commune Fr. and Microporus xanthopus (Fr.) Kuntze from Phulchowki, central Nepal

2023-07-23T04:34:15+00:00

Mushrooms are widely known for their therapeutic properties, which can be attributed to the secondary metabolites they produce. This study aims to evaluate different phytochemical constituents of two saprophytic mushrooms, namely Schizophyllum commune Fr and Microporus xanthopus (Fr.) Kuntze, collected from forest around Phulchowki, Lalitpur, Nepal. The total phenolic, flavonoid, vitamin C, β-carotene, and lycopene contents of S. commune were found higher than M. xanthopus (143.21 ± 0.003 vs. 108.45 ± 0.112 mg GAE/100 g; 91.55 ± 0.121 vs. 49.72 ± 0.073 mg QAE/100 g; 26.67 ± 0.015 vs. 3.15 ± 0.170 mg AA/100 g; 0.036 ± 0.001 vs. 0.013 ± 0.002, and 0.026 ± 0.002 vs. 0.01 ± 0.004 mg carotenoid/g; respectively) in the methanolic extracts. This study suggests that these mushrooms might have some medicinal values.

Forest structure and biodiversity patterns along elevational gradients in eastern Nepal

2023-08-03T07:10:50+00:00

This study aimed to assess the forest structure, composition, and diversity pattern at different elevations in Morang District, eastern Nepal, using stratified random vegetation sampling technique in five forests: Bhaunne, Raja-Rani, Murchungi, Adheri, and Sagma. Trees, shrubs and herbs of each forest was sampled through quadrat of 20 × 20 m², 5 × 5 m², and 1 × 1 m² each respectively. A total of 315 plant species belonging to 82 families and 255 genera found by this study. A total of 50 quadrats each for trees, shrubs and herbs sampled during this study. A total 10 quadrats studied for each life form from each forest. This study obtained 5,037 individuals across all forests. The highest number of species (55) was recorded from Raja Rani forest, and the highest tree density (985 ind ha^-1) was observed in Adheri forest. The highest density of shrub (24400 ind. ha^-1) and herbs (44.1 ind.m^-2) were recorded in Sagma forest. The Shannon Wiener index value of herb layer was found to be the highest (3.79) at Bhaunne forest. This value for shrub layer was 2.98 and tree layer was 3.12 at Sagma which was the maximum among forests. The concentrations of dominance value were high for herb and shrub layer in Bhaunne forest, and it was maximum for the tree layer in Adheri forest. The forest species composition were significantly different (p ≤ 0.001) among each other. Total basal area of shrub layer and tree layer recorded were maximum (111.52 m²ha^-1 and 612.08 m²ha^-1) in Sagma and Adheri forest, respectively. The number of trees decreased with increasing elevation, while shrubs increased, and herbs showed a U-shaped trend. The dominant tree species were Senegalia catechu, Shorea robusta, Terminalia alata, and Schima wallichii in Bhaunne, Raja-Rani, Murchungi, and Sagma forest, respectively, with Shorea robusta being dominant in Adheri forest. These findings have important implications for forest management and conservation efforts in the region.