Biosorptio Of Cd2+ By Wildtype And Cadmium Resistant, CdR-99 Cell Line Of Chlorella Vulgaris

Removal of heavy metals is very important in wastewater treatment process, due to their toxic effects on the environment. Biological treatment has attracted researchers for years since it has many advantages over physical and chemical methods for removing heavy metals from wastewater. The purpose of this research was to assess the biosorption of Cd2+ by wildtype (WT) and CdR-99 resistant line of Chlorella vulgaris confirming mechanisms of resistance to Cd2+ toxicity and the effect of the variable concentrations of Cd2+ on their growth. Exposure of both algal cell lines to increasing Cd2+ concentrations resulted in progressive inhibition of growth as revealed by growth experiments. The higher ID50 value (38 μM Cd2+) of CdR-99 resistant line exhibited some degree of resistance to Cd2+ toxicity. Metal content was determined by flame atomic absorption spectrometry (FAAS). When exposed to the growth medium containing 50 μM Cd2+, CdR-99 resistant isolate proved to be efficient cell line compared to the WT, in terms of adsorption and removal of Cd2+ at 15 min and 48 hr interval of time respectively. Extracellular Cd2+ adsorption was found significantly higher than intracellular uptake in both the tested cell lines. Total Cd2+ accumulation and distribution between the external and internal cell fractions of the CdR-99 were significantly higher to the WT. Thus, the CdR-99 cell line appeared more resistant to Cd2+ toxicity and hence may be used for wastewater treatment and remediation of metal contaminated sites.

Hydrochemical Assessment Of Jhilmila Lake, Kanchanpur, Nepal

Freshwater contamination remains a challenging issue for the sustainable management of wetland ecosystems. This study aims to evaluate the water quality of Jhilmila Lake, Kanchanpur, Nepal by adopting standard test procedures, geochemical indices, and multivariate statistical analysis. The surface water samples were collected during the postmonsoon season in 2018 to assess the hydrochemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS) and dissolved oxygen (DO), ammonium (NH4+ ), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), sulphate (SO42-), nitrate (NO3-), phosphate (PO43-), bicarbonate (HCO3-) and total hardness (TH). The EC ranged from 162-190 µS/cm while TDS was 87-101 mg/L. The concentration of DO in the lake was in the range of 4.77-6.21 mg/L, indicated mild organic pollution. Moreover, the results revealed the moderate alkaline nature of water with the pattern of average ionic dominance of Ca2+>Na+>Mg2+ >K+>NH4+ for cations, and HCO3˗> Cl-> SO42- > NO3- > PO43- for anions. The principal component analysis demonstrated four major components indicating the association of EC, TDS, Ca2+, Mg2+, and HCO3- ; Na+ , PO43- and SO42-; NO3- and K+ ; and Cl- for PC1, PC2, PC3, and PC4, respectively exhibiting both the geogenic and anthropic origin. Overall, the Jhilmila Lake was less polluted, and all the measured water quality parameters were found within permissible limits in terms of drinking purposes. The findings of this study could help for the sustainable management of the lake by providing better insights into the water quality and hydrochemistry of the lake.

Study Of Tremulous Signatures In Devanagari Nepali Script

Signatures, as one of the behavioral human characteristics are generally recognized as legal means for verifying an individual's identity by administrative and financial institutions. A signature is developed by a person and it can change over time. Signatures are prone to influences by age, physical and mental conditions. In this study tremulous signatures including questioned and standards related to 50 real cases resolved by National Forensic Science Laboratory of Nepal were collected. The time interval between questioned and standard signatures was up to ten years. Sixteen major characteristics along with their forty-one sub characteristics of each case were studied. Among sixteen major characteristics in the tremulous signatures, study shows that the characteristics like the style of writing in hand printed form, pen pauses, medium pen pressure, poor line quality, pen lifts are most prominently observed. Tremors were absent mostly in the terminal strokes of letters. The letters written were varied in size and those were 6% small, 70% medium and 24% large. Interestingly no any retouch attempts were found to complete the shape of letters.

Characterizations Of Water Quality In West-Seti and Tamor River Basins, Nepal

This study presents the geochemical composition and water quality of waters in the West-Seti and Tamor River basins in Nepal Himalaya with the aim to reveal their hydrochemical characteristics and to evaluate the water quality. Water samples were collected from 18 sites of the rivers in the pre-monsoon season and analysed the physicochemical parameters to characterize their quality. The parameters- temperature, pH, conductivity, and total dissolved solids were measured in the field, while the major ions (Na+, Ca2+, Mg2+, Si4+, SO42−, NO3−, HCO3−, Cl−, and F−) were analyzed in the laboratory. Overall results of physicochemical parameters revealed that the ionic strength is much distinct; however, the waters are chemically pure in both the river basins with very less electrical conductivity (<250 µS/cm) and total dissolved solids (<120 mg/L). Bicarbonate (HCO3−) has a significant correlation with Ca2+ and Mg2+ suggesting carbonate rock weathering as the dominant geochemical process in both of the basins. The concentrations of Ca2+, Mg2+, and HCO3− in the water of the West-Seti is relatively higher than the waters in the Tamor River basin. Mostly, the geochemical facies of both the rivers are characterized by the Ca-Mg-HCO3- type (88.9%), with dominant carbonate dominated lithology. However, hydrochemical facies clearly suggested spatial discrimination between two basins with dominant geogenic signatures as Ca-SO4-Cl type water facies are also reported from the Tamor River basin. The results exhibited that the concentrations of measured parameters were relatively very low and within the WHO guideline values and currently under a safe level of the water quality for drinking and ecosystem health perspectives; however, further in-depth research is recommended in the periodic basis to assess traces of climate change imprints, and anthropogenic interferences for more consistent and reliable dataset. The findings of this study could be useful for the water quality management in the glacier-fed Himalayan River basins.

Assessment of Air Pollution Impact on Micro-Morphological and Biochemical Properties Of Callistemon citrinus (Curtis) Skeels And Lagerstroemia indica L.

The urban air pollution is a major environmental concern, particularly in the developing countries and in their major cities. In the present study an attempt has been made to assess the air pollution effect on micromorphological and biochemical parameters of Callistemon citrinus and Lagerstroemia indica. Biochemical parameters were analyzed by using standard protocol. one-way analysis of variance was performed with SPSS software, v. 20.0, and Duncan test (p ≤ 0.05) was used to compare averages of all measured biochemical parameters and micromorpholgical features. There was a decrease in number of stomata of both species at highly polluted site compared to less polluted site (control). Stomatal index of both species was found to be reduced in polluted site when compared to control. The number of clogged stomata was less in control area samples when compared to polluted sample. A number of epidermal cells were significantly decreased at heavily polluted site. Total chlorophyll content and leaf extract pH in both the plants were found to be significantly higher in control sites than in heavily polluted sites. Ascorbic acid, relative water content, and Air Pollution Tolerance Index (ATPI) was found to be significantly higher at more polluted plants than at control. Based on the present study results, Callistemon citrinus emerged as the most tolerant species with the highest APTI. Hence, Callistemon citrinus can be suggested for plantations along the roadside of urban areas for green belt development.

Phytochemical and Antioxidant Properties Of Traditionally Used Mistletoes In Nepal

Mistletoes are being used for food or beverage and for variety of medicinal purposes. In Nepal, mistletoes are traditionally used as fodder and as remedy to cure various ailments. In this study, methnolic extracts of seven common mistletoe species (Helixanthera ligustrina, Macrosolen cochinchinensis, Scurrula elata, S. parasitica, Viscum album, V. articulatum and V. liquidambaricola) were analyzed for their phytochemical constituents and antioxidant potential. The total flavonoid content (TFC) and total phenol content (TPC) were quantitatively determined by aluminum chloride colorimetric and folin-cioalteau reagent methods, respectively. The TFC was found highest for V. album (31.5 ± 2.3 mg QE/g) and lowest for M. cochinchinensis (24.9 ± 2.3 mg QE/g). Similarly, highest total phenolic content was found in S. parasitica (32.9 ± 2.5 mg GAE/g) and lowest in V. album (20.6 ± 2.1 mg GAE/g). The antioxidant activity measured by DPPH radical scavenging assay was found best for S. parasitica (with lowest IC₅₀ value; 26.0 ± 0.7 µg/ml) among the studied mistletoes. Overall analysis provides scientific evidence in favor of indigenous use of these mistletoes as a source of fodder, food and for medicinal purposes

Phytochemical Analysis, Antioxidant, Antimicrobial Activities and GC-MS Profiling Of Drymaria Diandra Blume

Drymaria diandra is used in Nepalese traditional medicine to treat various ailments. The hexane, dichloromethane, ethyl acetate, methanol and 50% aqueous methanol extracts of D. diandra were prepared and screened for the presence of different classes of phytochemicals. Methanol and 50% aqueous methanol extracts showed the presence of phenolics, flavonoids and carbohydrates so their total contents were estimated. The highest amount of phenolics and flavonoids were found in methanol extract (190.58±2.21 mg GAE/g extract and 69.25±7.91 mg CE/g extract respectively). The highest amount of sugar was found in 50% methanol extract (185.60±2.53 mg GE/g extract). Similarly, the extracts were tested for the antibacterial activity against one gram negative bacteria, Escherichia coli and one gram positive bacteria Staphylococcus aureus. All the tested extracts showed good antibacterial activity against both bacteria with the inhibition zone ranging from 10 -22 mm. The free radical scavenging activity was determined using DPPH free radical. Both methanol and 50% aqueous methanol extracts showed strong antioxidant activity (IC50 13.61 and 16.94 μg/ml respectively). The GC-MS analysis of hexane extract revealed the presence of more than 22 compounds. However, 9 compounds were identified by comparing the mass fragmentation pattern of each compound with the standard NIST mass spectral database

Using Wavelet Transform To Extract Frequency Content In Electric Field Radiated By Unusual Lightning Activity

In this frequency spectrum electric fields radiated by the unusual lightning activities have been computed using the wavelet transform technique. The unusual lightning activities have very recently been identified activities and are very poorly understood among the lightning community. As the electric fields are very recently identified and are measured in time domain, to the best of our knowledge, their frequency content has not been studied as of today. To understand the physics of the discharge mechanism of such events, the frequency domain information plays a significant role. In order to extract frequency domain information from the time domain electric field signatures the wavelet transform technique has been employed. For the purpose, the electric field pertinent to the unusual activity, has been divided into two parts namely main activity and the preceding opposite polarity field change. From the computation, it is found that the opposite-polarity field change radiates energy in the spectral range of 2 kHz to 173 kHz whereas, the main activity predominantly radiates in the frequency range 2 kHz to 162 kHz. Such a wider spectral range that the unusual activities radiate have not been reported for the other known activities such as positive and negative return strokes. Evidently, the unusual events have some unique origin of discharge unlike the known activities. Further, as the unusual events were noticed in the temperate region (Uppsala, Sweden) and Sub-tropical climatic zone (Kathmandu, Nepal), it should have some common source of origin between two regions.

Extracting Features of Transient Electric Fields With Fourier And Wavelet Transform–A Case Study Of Lightning Positive Return Stroke

Frequency domain information were extracted from the time domain electric fields pertinent to the lightning positive return strokes applying Fourier transform and Wavelet transform. The electric field radiated by positive ground flashes striking the sea were recorded at 10 ns resolution at a coastal station to minimize the propagation effects. The frequency spectrum of the electric field of positive return strokes were computed applying the Fourier transform technique in the range of 10 kHz to 20 MHz owing to the fact that this range of frequency is of very much interest to the researchers and design engineers. The amplitude of the energy spectral density decreases nearly as ƒ-1 from 10 kHz to about 0.1 MHz and drops nearly as ƒ-2 up to 8 MHz. Applying the wavelet transform technique, the same positive return strokes are found to radiate in the frequency range of 5.5 to 81 kHz with the average spread distribution of 13.6 kHz to about 30 kHz. From frequency spectrum obtained from the Fourier transform it is difficult to identify as which phase of the return stroke radiates in the higher frequency range and that in the lower frequency range, whereas, one can easily identify from the frequency spectrum obtained with the wavelet transform that ramp portion of the positive return stroke radiates in the larger spectral range as compared to that of initial peak of the return stroke. Also, from the spectral density map obtained from wavelet transform one can easily observe the contribution of each phase in a range of frequency, which is not possible from the Fourier transform technique. Clearly, the wavelet transform is much more powerful tool to extract the frequency domain information of a non-stationary signal as compared to that of Fourier transform.

Dirac Particles in Coulomb Like Field in FLRW–Space

Behaviour of the Dirac particle in Coulomb like field in FLRW space is investigated. Firstly, the Maxwell equations, in terms of the vector potentials are solved to identify the Lorentz and Coulomb like gauges. The radial Coulomb like potential is solved in terms of Legendre functions. Then the Dirac equation is generalized to include this potential and the angular part is separated and solved. The radial and temporal parts of the mass less case is also separated and solved. But the massive case remains coupled. This is still reduced to the case where the Dirac particle can be represented as being in a combined gravitational and electric potential. This effective potential is found to develop an attractive well, which may require a revisit to the recombination era.