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  • Author or Editor: A. Shukla x
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Abstract

The coordination complex of Cu (II) with the Schiff base derived from 4-chloroaniline with salicylaldehyde have been synthesized and characterized by micro analytical data; FT–IR, UV–Vis, FAB-mass and thermal analysis studies. Thermal data show degradation of complexes. We carried out thermal analysis at three different heating rates viz. 5, 10 and 20 °C per min. The activation thermodynamic parameters, such as activation energy (E∗), entropy of activation (ΔS∗), enthalpy of activation (ΔH∗) and Gibbs free energy (ΔG∗) have been calculated with the help of TG, DTA and DTG curves using Coats–Redfern method. The stoichiometry of the complexes are in 1:2 (M:L) molar ratio. Synthesized complex has been tested for their reactivity and substitution behaviour.

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An impact of temperature, light and relative humidity were studied on root colonisation by mycorrhizal fungi and on pine seedling growth. Moderate and high light intensities favoured mycorrhizal colonisation and seedling growth. Pine seedlings inoculated with Pisolithus tinctorius compared to other fungi attained maximum growth. Survival of pine seedlings was higher under moderate light intensity than low and high light intensity. Seedling growth and mycorrhizal colonisation was better at 25°C than 10°C. Variation in humidity did not show much difference in mycorrhizal colonisation and seedling growth. However, seedling survival was greater at high than at low humidity. Pine seedlings showed best survival with 0.5 P level (46.153 mg P/kg soil) of phosphorus at 25 °C temperature and under moderate light intensity. Among the mycorrhizal fungi used P. tinctorius was the most effective endophyte and was followed by Laccaria laccata, Rhizopogon luteolus and Collybia radicata under various physical factors.

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Abstract  

When a biological system is either accidentally or intentionally exposed to radiation, the energy absorbed triggers a number of successive events including damage to living tissues. Major radiation damage is due to the aqueous free radicals generated by the radiolysis of water. These free radicals act as molecular marauders and in turn damage DNA, mitochondrial membrane, lipid, cellular protein, resulting in cellular dysfunction and mortality. In view of the above mentioned facts an experiment was conducted to study the genotoxic effects of γ radiation and its dose effectiveness. The present experiment was conducted on samples of plasmid pBR322 DNA as the in vitro experimental model devoid of any DNA repair and replication machinery. The samples were exposed to different doses of gamma radiations from 1 to 200 Gy. Exposure of plasmid pBR322 DNA to γ radiation resulted in production of single strand breaks as a result of which, the supercoiled (SC) form was converted to relaxed form (RL). Exposure of radiation, even at very low dose of 1 Gy, exhibited a significant damage to DNA resulting in about 70% SC form and 30% RL form of DNA. At a dose of 10 Gy the SC form was reduced to about 37% and further 5% at a dose of 50 Gy with about 88.5 and 6.5% RL and linear (L) forms of DNA respectively. Thus, the disappearance of supercoiled form of plasmid pBR322 DNA was found to be directly related to radiation dose and exhibited a radiation dose dependent pattern.

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Abstract  

The study summarizes radiological characteristics of Banduhurang open cast mine which includes qualitative and quantitative behavior of 222Rn concentration, external gamma radiation level over the mine pit as well as in its adjoining environment, long-lived alpha (LLα) activity concentration associated with the respirable size of ore dust and assessment of dose to the mine workers in 2006–2008. The investigations reveal that geometric means (χg) of measured radon concentration were 36.39, 38.69, 26.64 and 24 Bq m−3 with respective geometric standard deviations (σg) were 1.52, 1.55, 1.36 and 1.68 Bq m−3 and χg of gamma absorbed dose rates were 0.54, 0.64, 0. 45 and 0.15 μGy h−1 with respective σg were 1.63, 1.53, 1.52 and 1.72 μGy h−1 over the mine pit, ore yard, waste yard and in the surrounding environment within a 10 km radius to the mine, respectively. The χg of LLα activity was observed to be 16 mBq m−3 with σg of 1.9 mBq m−3. The annual mean effective dose equivalent received by the member radiation workers of Banduhurang mine was estimated to 1.41 mSv y−1, which is about 7% of the prescribed dose limits of 20 mSv y−1.

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Yellow mosaic and leaf curling symptoms were observed on Ageratum conyzoides plants in a survey made during 2007–09 at Gorakhpur and nearby locations of North-Eastern Uttar Pradesh, India. The incident of disease was significantly high with severe symptoms. Due to presence of whiteflies in the field, begomovirus infection was suspected. Therefore, polymerase chain reaction (PCR) was performed with begomovirus specific primers (TLCV-CP). Total genomic DNA was isolated from infected as well as healthy leaf samples. In gel electrophoresis an ∼800 bp amplicon was obtained in diseased leaf samples as expected, while no amplicon was found in healthy plants.Amplicons obtained were directly sequenced and submitted to the GenBank with the accession number GQ412352 and a phylogeny tree was constructed with the available sequences in the Genbank. Based on the highest nucleotide similarity (98%), amino acid similarity and close relationship with isolates of Ageratum enation virus, the present isolate was considered as an isolate of Ageratum enation virus.

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Summary  

The present paper reports the Differential Scanning Calorimetric (DSC) study of some Ag doped Se-Te chalcogenide glasses. DSC runs were taken at different heating rates. Well-defined endothermic and exothermic peaks were obtained at glass transition and crystallization temperatures. The variation of glass transition temperature T gwith Ag concentration has been studied. It has been found that T gdecreases with increase in Ag concentration. The heating rate dependence of T gis used to evaluate the activation energy of glass transition (DE t). The value ofDE thas been found to increase with increase in Ag concentration followed by nearly constant value at higher concentrations of Ag.

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Nitrogen use efficiency, more specifically physiological nitrogen use efficiency depends primarily on management of N, one of the major essential nutrients. It is required in increased agricultural production and may possibly cause soil toxicity if fed in excess. Rate of N fertilizer application in fertile agricultural field and improved productivity in sterile soils require the improvement of NUE. A field experiment was therefore conducted to evaluate the effect of different N levels (N0, N50, N100 and N200) on rice genotypes. Vegetative plant growth was found to be reduced under N0 while improved at N200 level. Among the genotypes, highest PNUE (34.94) and correspondingly higher yield (7.15 ton ha−1) was observed for Krishna Hamsa. The other traits viz. plant height, no. of productive tillers and LAI exhibited higher values for Krishna Hamsa as well. Hence these can be utilized as physiological markers for the selection of rice genotypes efficient in N use.

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The paper deals with morphological and physiological variability of Colletotrichum falcatum Went on different temperature, pH, medium, nitrogen sources, carbon sources and also first time reporting of the two National Pathotypes from North East Zone of Uttar Pradesh, India. Thirty-four isolates were isolated from infected samples of different sugarcane varieties during survey and maintained on Oat Meal Agar (OMA) slants as well as on the Petri dishes at 30±1 °C. These isolates showed the variability in their optimum radial growth pattern. The optimum radial growth of all isolates was recorded at 8, 10 and 12 days. Six isolates exhibited maximum radial growth (90 mm diam) in 8 days, while the other 10 isolates attained same growth in 10 days. Remaining 14 isolates took 12 days to attain same growth. Pathogenecity of 34, isolates has been tested on 12 host differentials of sugarcane genotypes only SES594 was found resistant and others showed the variable response, while highly susceptible reaction to be found in three isolates (R0704, R0720 and R0728). These three isolates gave maximum spores on OMA followed by PDA medium and higher dry mycelium weight was observed in Richard’s liquid medium as compared to others. The maximum growth was recorded for these three isolates on potassium nitrate and sodium nitrate as nitrogen sources. Growth regulators like IAA and IBA at lower concentration enhances the growth while higher concentration showed adverse affect. When these three isolates were compared with the national level pathotypes, viz. Cf01 (Co1148), Cf08 (CoJ64) and Cf09 (CoS767) reaction in differential and spores inoculation technique it was found that isolates showed similar reaction like National Level pathotypes. Hence, it was concluded that these three isolates are belonging to new pathotypes.

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Abstract  

In the environs of uranium mining, milling and processing facilities and in the uranium mineralized terrain, a little higher ambient radon concentration and gamma radiation level may be expected in comparison with natural background. The present study gives a brief account of atmospheric radon concentration, gamma absorbed dose rate and radiation dose received by the members of public in the vicinity of Narwapahar uranium mine. The ambient radon concentration in the air in the study area was found to vary from 5 to 107 Bq m−3 with geometric mean of 24 Bq m−3 and geometric standard deviation of 1.74 Bq m−3. The measured gamma absorbed dose rate in air at 1 m above the ground ranged from 87 to 220 nGy h−1 with an overall arithmetic mean of 128 ± 18.5 nGy h−1. The mean annual effective dose received by the members of public from inhalation of radon and its progeny and external gamma exposure was estimated to be 0.32 mSv year−1, which is comparable to other reported values elsewhere.

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Abstract  

A brief study on dissolved radionuclides in aquatic environment, especially in ground water, constitutes the key aspect for assessment and control of natural exposure. In the present study the distribution of natural uranium and 226Ra concentration were measured in ground water samples collected within a 10 km radius around the Narwapahar uranium mine in the Singhbhum thrust belt of Jharkhand, India in 2007–2008. The natural uranium content in the ground water samples in this region was found to vary from 0.1 to 3.75 μg L−1 with an average of 0.87 ± 0.73 μg L−1 and 226Ra concentration was found to vary from 5.2 to 38.1 mBq L−1 with an average of 13.73 ± 7.34 mBq L−1. The mean annual ingestion dose due to intake of natural uranium and 226Ra through drinking water pathway to male and female adults population was estimated to be 6.55 and 4.78 μSv y−1, respectively, which constitutes merely a small fraction of the reference dose level of 100 μSv y−1 as recommended by WHO.

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