The space charge trapping/detrapping in thermally charged polyimide (PI) samples have been studied by means of “Final Thermally
Stimulated Discharge Current” (FTSDC). We investigate the effects associated with space charge behavior in PI near glass transition
region. The FTSDC spectra consist of space charge peak attributed trapping of charges at different trapping levels. The peak
positions are found to be very sensitive with poling time, discharging time, and heating rate. The apparent activation energy
distributed in the range from 0.51 to 1.12 eV, and the charge released has been found to be varying with poling temperature
(Tp) and poling time (tc)/discharging time (td). The decay of space charge (Q) resembled an agreement with interfacial polarization.
4,4′-bismaleimidophenyl methane (BM) and 3,3′-bismaleimidophenyl sulfone (BS) were blended in solution using weight ratios 3∶1 (MS31), 2∶1 (MS21), 1∶1 (MS11), 1∶2 (MS12) and 1∶3 (MS13). Chain extended bismaleimide resins were also prepared by treating BS/BM with 4,4′-diaminodiphenyl ether in molar ratios of 1∶0.3 (BM-E and BS-E resins). These resins were also blended with bismaleimides and the curing characteristics were evaluated by differential scanning calorimetry. Increase in BM content in BM∶BS blends or increase in chain extended bismaleimide content in BM-E∶BS or BS-E ∶ BM blends resulted in a reduction of melting and curing temperatures. Indication about the extent of cross-linking was obtained from solubility measurements (in DMF) of isothermally cured resins (180 °C, lh and 220 °C, lh in an air oven). Thermogravimetric analysis of samples isothermally cured at 180 °C and 220 °C (lh each) was carried out in nitrogen atmosphere. Improvement in thermal stability of chain extended bismaleimides was observed on blending.
Leaf rust resistance genes Lr9 and Lr10 were detected in wheat (Triticum aestivum) genotypes by PCR based STS markers. Out of sixty-two elite wheat genotypes, screened for the presence of leaf rust resistance gene Lr10, nineteen genotypes revealed the presence through PCR analysis with the primers specific to Lr10 gene. Validation of the marker for Lr9 gene in the parental lines followed by successful detection of the gene in F4 lines out of cross HP1633 (Lr9) X HP1776, was also done. Usefulness of molecular markers for the detection of rust resistance genes in different genotypes is discussed.
The objective of the present investigation was to develop and validate a stability indicating liquid chromatography (LC) method which should possess potential to separate flucloxacillin as well as all the degradation products. Simultaneously, our aim was also to identify, separate, and characterize the major degradation product (DPs) of flucloxacillin, generated under various stress conditions. To achieve this objective, flucloxacillin was subjected to hydrolytic, oxidative, photolytic, and thermal stress as per International Conference on Harmonization (ICH) guidelines Q1A(R2). The drug was found to degrade in acidic, alkaline, neutral, and oxidative stress conditions and showed stable behavior in photolytic and thermal stress conditions. In total, seven degradation products were formed, which were separated on a C-18 column employing a gradient high-performance liquid chromatographic (HPLC) method. A complete mass fragmentation pathway of the drug was established with the help of multi-stage (MSn) and mass spectrometry/time of flight (MS/TOF) accurate mass studies. Then the stress samples were subjected to LC-MS/TOF studies, which provided the fragmentation pattern along with the accurate masses for a major degradation product. The entire mass spectral studies helped to identify the degradation product so as to propose its best possible structure. Finally the total information was used to establish the degradation pathway of the drug.
Authors:R. Singh, D. Datta, Priyamvada, S. Singh, and R. Tiwari
The aim of this study was to develop a PCR based assay for an efficient selection of
resistance gene in breeding material. The two primer pairs designed from the
gene sequence amplified specific DNA fragments in the genotypes carrying
and did not give a signal with near isogenic line and other lines containing different
genes. The genetic linkage of these molecular markers to
gene was tested on a segregating F
population derived from cross between the stripe rust resistant genotype carrying
(FLW10) and the susceptible line WH542. The data demonstrated that the markers derived from
gene sequence are completely linked to
, which will enable to combine this gene with other stripe rust resistance genes in wheat breeding programmes.
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:D. Garg, S. Sareen, S. Dalal, R. Tiwari, and R. Singh
Terminal heat referred to as increase in temperature during grain filling, is one of the important stress factors for wheat production and is responsible for decline in wheat production in many environments worldwide. In order to meet the challenges of high temperature ahead of global warming, concerted efforts are needed to evaluate wheat genotypes for heat tolerance and develop genotypes suitable for such stressed environments. Twenty-seven advanced wheat genotypes developed for stress and normal environments by different research centres were evaluated during 2009–10 and 2010–11 under timely sown (normal) and late sown (heat stress) environments. Analysis of variance revealed that the genotypes differed significantly in grain filling duration (GFD), grain growth rate (GGR) and thousand-grain weight (TGW). Out of 27 genotypes, 16 were found to be tolerant for thousand-grain weight under late planting (heat stress) during 2009-10 but only 12 were tolerant during 2010–11. Many of the genotypes registered more reduction in thousand-grain weight during 2010–11 as compared to 2009–10; the temperatures during 2009–10 were higher. The differences in grain filling duration under two conditions during both seasons as well as difference in temperatures during first half of grain filling explain the reduction pattern in the genotypes. GFD had significant negative correlation with temperatures during post heading period and the difference in GFD under two environments had positive correlation with these temperatures. The reduction in GFD had regression of 33.3% on reduction in GGR and reduction in GGR had regression of 41.6% on reduction in TGW genotypes AKW 1071, DBW 17, HS 277, K 7903, K 9107, NW 1014 and RAJ 3765 had less sensitivity to stress environments during both years.
Authors:S. Mishra, D. Tiwari, S. Prasad, R. Dubey, and M. Mishra
The role of dead biomasses viz., mango (Mangifera indica) and neem (Azadirachta indica) bark samples are assessed in the removal behavior of, one of important fission fragments, Cs(I) from aqueous solutions employing
a radiotracer technique. The batch type studies were carried out to obtain various physico-chemical data. It is to be noted
that the increase in sorptive concentration (from 1.0·10−8 to 1.0·10−2 mol·dm−3), temperature (from 298 to 328 K) and pH (2.6 to 10.3) apparently favor the uptake of Cs(I) by these two bark samples. The
concentration dependence data obeyed Freundlich adsorption isotherm and the uptake follows first order rate law. Thermodynamic
data evaluation and desorption experiments reveal the adsorption to be irreversible and endothermic in nature proceeding through
ion-exchange and surface complexation for both dead biomasses. Both bark samples showed a fairly good radiation stability
in respect of adsorption uptake of Cs(I) when irradiated with a 300 mCi (Ra-Be) neutron source having an integral neutron
flux of ∼3.85·106 n·cm−2·s−1 and associated with a nominal γ-dose of ∼1.72 Gy·h−1.
Authors:Ranjeet Kumar, R. C. Tripathi, and M. D. Tiwari
In the current scenario of the global economy and race for the next Asian super power, overall economic strength of the two countries, India and China, is a most debated topic. The future role of intellectual property protection especially in the form of patent system and the growth of industrialization for these two developing economies in ASIA may prove to be crucial over all other assets. In the current development scene of the changing global market supported by intangible asset of inventions protected mainly through the patents is emerging to play an important role. This paper elaborates the statistical research on patents granted/filed in the US Patent and Trade Mark office (US-PTO), PCT of WIPO and in the home countries over last 35 years of aforesaid two Asian countries. It is found that the economic and technological growth of both of the countries may make main difference primarily based on the level of patenting activity by them.
Authors:S. Mishra, D. Tiwari, S. Prasad, R. Dubey, and Manisha Mishra
The removal behavior of amorphous aluminum hydroxide for Hg(II) ions from aqueous solutions was investigated by employing
a radiotracer technique at micro down to trace level concentrations. The batch type experiments were performed to obtain various
physico-chemical parameters, viz., effect of sorptive concentration, temperature and pH. It was observed that the increase
in sorptive concentration (from 1·10−8 to 1·10−2 mol·dm−3), temperature (from 303 to 333K) and pH (from 3.4 to 10.3) apparently favored the uptake of Hg(II) by this solid. Similarly,
the presence of anions (six fold) viz., oxalate, phosphate, glycine and EDTA also enhanced the uptake behavior of aluminum
hydroxide for Hg(II). Whereas, the added cations viz., Na+, K+, Ba2+, Sr2+, Mg2+, Cd2+ and Fe3+ more or less suppressed the removal behavior of the adsorbent. Further, the adsorption process followed the classical Freundlich
adsorption isotherm and deductions of various thermodynamic data revealed that the uptake of Hg(II) on aluminum hydroxide
followed the ion-exchange type mechanism and thermodynamically it was found to be endothermic in nature.