A field experiment was carried out to investigate the establishment of phosphate-dissolving strains of Azotobacter chroococcum, including soil isolates (wild type) and their mutants, in the rhizosphere and their effect on the growth attributes and root biomass of three genetically divergent wheat cultivars (Triticum aestivum L.). Four fertilizer doses were applied: 90 kg N ha—1, 90 kg N + 60 kg P2O5ha—1, 120 kg N ha—1and 120 kg N + 60 kg P2O5ha—1, besides a control plot without fertilizers or bioinoculants. Phosphate-solubilizing and phytohormone-producing parent soil isolates and mutant strains of A. chroococcum were isolated and selected following the enrichment method. On an overall basis the mutant strains performed better than the soil isolates for in vitro phosphate solubilization (11–14%) and growth hormone production (11.35%). Seed inoculation of wheat varieties with phosphate-solubilizing and phytohormone-producing A. chroococcum showed a better response over the control. Mutant strains of A. chroococcum showed a higher increase in grain (15.30%) and straw (15.10%) yield over the control and better survival (12–14%) in the rhizosphere as compared to their parent soil isolate (P4). Mutant strain M15 performed better in all three varieties in terms of increase in grain yield (20.8%) and root biomass (20.6%) over the control.
Authors:N. Kumar, Nitin Kumar, A. Shukla, S. C. Shankhdhar, and D. Shankhdhar
Global warming is rising as a serious concern affecting agricultural production worldwide. Rice is a staple food crop and the threshold temperature for its pollination is 35 °C. A rise in temperature above this value can cause pollen sterility and may severely affect fertilization. Therefore, a study emphasizing the rise in temperature with respect to pollen viability was conducted with eleven rice genotypes during kharif seasons of 2010 and 2011 in indigenous field conditions. Increasing mean temperature by 12 °C at full flowering was found to severely affect the spikelet attributes of the crop. All genotypes showed spikelet sterility above 90% during both seasons. The study indicated that increased temperature may limit rice yield by affecting spikelet fertility and grain filling. The net reduction in grain yield was 30.4% and 27.6% in 2010 and 2011, respectively. A clear reduction in pollen size under high temperature was shown by scanning electron microscopy.
Authors:A. N. Garg, A. Kumar, G. Maheshwari, and S. Sharma
Radioanalytical techniques have been applied in a study on (subclinical) hepatitis in Dobermann dogs. Cu levels in transcutaneous obtained full liver biopsies were quantified using INAA and 66Cu. A copper excretion study was performed in a group of completely normal Dobermann dogs and in six Dobermanns with elevated copper levels and suffering from subclinical hepatitis. 64Cu2+ was used to assess whether a normal bile flow and thus excretion was possible. All subjects underwent separately from this 64Cu2+ excretion study a 99mTc-Bis-IDA scintigraphy. The Cu levels in liver of these hepatitis patients vary from 600 to 1600 mg . kg-1 whereas 100-300 mg . kg-1 is probably normal for healthy Dobermann dogs. These Cu levels match fully with histopathology results and clinical observations. Measurements during a 2 years' evaluation period showed a clear relation between the existence of subclinical hepatitis and increased Cu levels without a sign for cholestasis or an abnormal bile flow.
Authors:N. Kumar, M. Graham, S. Jha, and S. Chaturvedi
The understanding of the bio-geochemical behavior of the uranium radionuclides in the environmental matrices is crucial for
the health safety point of view. The research was carried out in munitions testing sites New Golloway (SW) of Scotland at
the Dunderann firing range which is contaminated with depleted uranium and site is particularly important because it provides
a controlled environment for the investigation of post depositional association of Depleted Uranium (DU) in contaminated soils.
This study used the modified BCR sequential extraction method to investigates the association of DU in at the different sampling
location and in a control soil and were followed by elemental analysis using inductively coupled-optical Emission spectroscopy
(ICP-OES).The Certified Reference Material (CRM) were used for the validation of the concentration. The concentrations of
(Bureau of Reference) BCR-extracted Uranium (U) were in the range of 4–40 (±13.2) mg kg−1 for the DU-contaminated sites whilst U was barely detectable in the soil from the control site (Rebury Gun) RGW. With the
exception of RGH and RGW, the values for BCR-extracted U compared well with those obtained using Aqaua-regia. The obtained
result showed that the maximum Uranium deposition is at RGE and it is 20 mg kg−1 before hitting the target, the 6 mg kg−1 at RGH and minimum is at RGG and RGW control site.
Authors:N. Sivaraman, R. Kumar, S. Subramaniam, and P. Vasudeva Rao
A rapid and high resolution separation of lanthanides by HPLC technique has been developed using Di-(2-ethylhexyl) phosphoric acid (HDEHP) coated reverse phase column and a-hydroxy isobutyric acid as the complexing reagent for elution. A gradient elution technique has been developed for achieving the separation of the entire lanthanide series. Isocratic elution procedure has also been developed for the separation of lighter (La to Gd) as well heavier lanthanides (Lu to Tb). This paper describes the separation methods developed and their application for the determination of lanthanides in a fission product mixture.
Authors:N. Nathawat, M. Kuhad, A. Patel, R. Kumar, and C. Goswami
The interaction between salinity (8 and 12 dS m
) and three levels (40, 80 and 120 kg ha
) of different forms of nitrogen (NO
) were studied in
cv. RH-30. The plants were salinized with 8 and 12 dS m
at 35 and 55 days after sowing. The relative water content (RWC), water potential (Ψ
) and osmotic potential (Ψ
) exhibited a marked decline under salinity stress. The application of the combined form (NO
) of nitrogen (120 kg ha
) considerably improved the water status and mitigated the adverse effect of salinity on growth. The salinity-induced osmotic effect led to stomatal closure and caused a substantial reduction in net photosynthetic rate (P
), stomatal conductance (g
) and transpiration rate (E) at the pre-flowering and flowering stages (45 and 65 DAS). Salinity effects were considerably moderated by additional nitrogen supply, which varied with the source of nitrogen, the level of salinity/fertilizer and the stage of plant growth. The inhibition in photosynthesis was relatively greater in ammonium-fed (NH
) than in nitrate-fed (NO
) plants, while the transpiration rate was relatively lower in nitrate-fed plants grown either with or without saline water irrigation. The nitrate form of nitrogen @ 120 kg ha
proved best in alleviating the adverse effect of salinity on photosynthesis and transpiration at both the growth stages.
A stability-indicating gradient reverse-phase liquid chromatographic method was developed for the quantitative determination of process-related impurities and forced degradation products of oxcarbazepine in pharmaceutical formulation. The method was developed by using Inertsil cyano (250 × 4.6 mm) 5 μm column with mobile phase containing a gradient mixture of solvent A (0.01 M sodium dihydrogen phosphate, pH adjusted to 2.7 with orthophosphoric acid and acetonitrile in the ratio of 80:20 v/v) and B (50:40:10 v/v/v mixture of acetonitrile, water, and methanol). The flow rate of mobile phase was 1.0 mL min−1. Column temperature was maintained at 25°C and detection wavelength at 220 nm. Developed reverse-phase high-performance liquid chromatography (RP-HPLC) method can adequately separate and quantitate five impurities of oxcarbazepine, namely imp-A, imp-B, imp-C, imp-D, and imp-E. Oxcarbazepine was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation. Oxcarbazepine was found to degrade significantly in acid, base, and oxidative stress conditions. The degradation products were well resolved from oxcarbazepine and its impurities. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.
Authors:R. S. Tiwari, N. Mehta, R. K. Shukla, and A. Kumar
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 Tgwith Ag concentration has been studied. It has been found that Tgdecreases with increase in Ag concentration. The heating rate dependence of Tgis used to evaluate the activation energy of glass transition (DEt). The value ofDEthas been found to increase with increase in Ag concentration followed by nearly constant value at higher concentrations of
Authors:S. Kumar, N. Rawat, B. Tomar, V. Manchanda, and S. Ramanathan
Sorption of technetium on hematite colloids, at varying pH (3–10), has been studied in absence and presence of humic acid
using 95mTc-96Tc radiotracers. Technetium was found to be weakly sorbed on hematite at lower pH (<5) values, while no sorption was observed
at higher pH values. Humic acid was found to have no effect on the sorption of technetium on hematite under aerobic conditions,
while at lower pH values small reduction was observed which was attributed to the reduced zeta potential of the hematite colloids
owing to the strong sorption of humic acid.
Authors:N. Kumar, D. Sangeetha, R. Goyal, and P. S. Reddy
A simple, selective, and stability-indicating reverse phase liquid chromatographic method has been developed and validated for the simultaneous determination of impurities and forced degradation products of quetiapine fumarate. The chromatographic separation was achieved on Inertsil-3 C8, 150 mm × 4.6 mm, 5 μm column at 35°C with UV detection at 217 nm using gradient mobile phase at a flow rate of 1.0 mL/min. Mobile phase A contains a mixture of 0.01 M di-potassium hydrogen orthophosphate (pH 6.8) and acetonitrile in the ratio of 80:20 (v/v), respectively, and mobile phase B contains a mixture of 0.01 M di-potassium hydrogen orthophosphate (pH 6.8) and acetonitrile in the ratio of 20:80 (v/v), respectively. The drug product was subjected to the stress conditions of oxidative, hydrolysis (acid and base), hydrolytic, thermal, and photolytic degradation. Quetiapine fumarate was found to degrade significantly in acid, base, and oxidative stress conditions. The degradation products were well resolved from main peak and its impurities. The mass balance was found to be in the range of 96.6–102.2% in all the stressed conditions, thus proved the stability-indicating power of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.