Showing papers by "Bareilly College published in 2012"

Nanotwinning and structural phase transition in CdS quantum dots

Abstract: Nanotwin structures are observed in high-resolution transmission electron microscopy studies of cubic phase CdS quantum dots in powder form by chemical co-precipitation method. The deposition of thin films of nanocrystalline CdS is carried out on silicon, glass, and TEM grids keeping the substrates at room temperature (RT) and 200°C by pulsed laser ablation. These films are then subjected to thermal annealing at different temperatures. Glancing angle X-ray diffraction results confirm structural phase transitions after thermal annealing of films deposited at RT and 200°C. The variation of average particle size and ratio of intensities in Raman peaks I2LO/I1LO with annealing temperature are studied. It is found that electron-phonon interaction is a function of temperature and particle size and is independent of the structure. Besides Raman modes LO, 2LO and 3LO of CdS at approximately 302, 603, and 903 cm−1 respectively, two extra Raman modes at approximately 390 and 690 cm−1 are studied for the first time. The green and orange emissions observed in photoluminescence are correlated with phase transition.

Nanotwinning in CdS quantum dots

Abstract: High resolution transmission electron microscopy, X-ray diffraction and photoluminescence measurements are carried out in order to study the defects in CdS quantum dots (QDs), synthesized in cubic phase by chemical co-precipitation method. The nanotwinning structures in CdS quantum dots (∼2.7 nm) are reported for the first time. Mostly CdS QDs are characterized by existence of nanotwin structures. The twinning structures are present together with stacking faults in some QDs while others exist with grain boundaries. Raman spectroscopy analysis shows intense and broad peaks corresponding to fundamental optical phonon mode (LO) and the first over tone mode (2LO) of CdS at 302 cm −1 and 605 cm −1 respectively. A noticeable shift is observed in Raman lines indicating the effect of phonon confinement. Fourier transform infrared spectroscopy analysis confirms the presence of Cd–S stretching bands at 661 cm −1 and 706 cm −1 . The photoluminescence spectrum shows emission in yellow and red regions of visible spectrum. The presence of stacking faults and other defects are explained on the basis of X-rays diffraction patterns and are correlated with photoluminescence spectrum. These nanotwinning and microstructural defects are responsible for different emissions from CdS QDs.

QSARs on human carbonic anhydrase VA and VB inhibitors of some new not yet synthesized, substituted aromatic/heterocyclic sulphonamides as anti-obesity agent

Abstract: This paper presents result of quantitative structure-activity relationships (QSAR) study realized with the PRECLAV, omega, brood and MOPAC software. The dependent property is the inhibitory activity against human carbonic anhydrase mitochondrial isoforms VA and VB. The calibration set includes 17 aromatic/heterocyclic sulphonamides incorporating phenacetyl, pyridylacetyl and thienylacetyl tails with three clinically used CA inhibitors namely AZA, TPM and ZNS molecules. The prediction set contains 24 others not yet synthesized substituted aromatic/heterocyclic sulphonamides having unknown observed values of activity. In the presence of prediction set, the predictive quality of QSAR of hCA VA (r(2) = 0.9789, F = 418.115, r(2)(CV) = 0.9689) and hCA VB (r(2) = 0.9768; F = 379.717; r(2)(CV) = 0.9637) is large. The obtained models suggest a slightly different inhibition mechanism for the two isoforms. Large percentage, in weight, of CONH molecular fragments seems to be favourable to inhibitory activity of both VA and VB.

Lattice distortion in ion beam synthesized silicon nanocrystals in SiOx thin films

Abstract: Lattice deformation is observed in nanocrystalline silicon synthesized by ion beam induced phase separation of SiOx films. The separation of silicon and silicon dioxide phases is achieved in the suboxide films after irradiation with a 100-MeV Ag beam. The interaction of a high-energy heavy ion beam with the material is dominated by an electronic energy loss process. A large amount of energy is deposited uniformly in the material through this process. Glancing angle X-ray diffraction (GAXRD), micro-Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), and energy-dispersive X-ray spectroscopy (EDX) measurements were carried out. The results confirm the occurrence of phase separation in non-stoichiometric silicon oxide by means of ion-beam irradiation leading to the formation of silicon nanocrystals in the films. The lattice of silicon nanocrystals is found to be deformed (contracted). The X-ray diffraction studies and HRTEM studies reveal the occurrence of two different phases of silicon, viz. cubic (fcc) phase and high-pressure (contracted lattice) phase, simultaneously. The observations are explained on the basis of ion beam induced pressure and thermal spike in the ion track.

Opto-structural studies of well-dispersed silicon nano-crystals grown by atom beam sputtering

Abstract: Synthesis and characterization of nano-crystalline silicon grown by atom beam sputtering technique are reported. Rapid thermal annealing of the deposited films is carried out in Ar + 5% H2 atmosphere for 5 min at different temperatures for precipitation of silicon nano-crystals. The samples are characterized for their optical and structural properties using various techniques. Structural studies are carried out by micro-Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy, and selected area electron diffraction. The optical properties are studied by photoluminescence and UV-vis absorption spectroscopy, and bandgaps are evaluated. The bandgaps are found to decrease after rapid thermal treatment. The micro-Raman studies show the formation of nano-crystalline silicon in as-deposited as well as annealed films. The shifting and broadening in Raman peak suggest formation of nano-phase in the samples. Results of micro-Raman, photoluminescence, and TEM studies suggest the presence of a bimodal crystallite size distribution for the films annealed at higher temperatures. The results show that atom beam sputtering is a suitable technique to synthesize nearly mono-dispersed silicon nano-crystals. The size of the nano-crystals may be controlled by varying annealing parameters.

Bioaccumulation and glutathione-mediated detoxification of copper and cadmium in Sphagnum squarrosum Crome Samml.

Abstract: Physiological and biochemical responses, metal bioaccumulation and tolerance potential of Sphagnum squarrosum Crome Samml. to Cu and Cd were studied to determine its bioindication and bioremediation potential. Results suggest that glutathione treatment increases the metal accumulation potential and plays a definite role in heavy metal scavenging. High abundance of Sphagnum in metal-rich sites strongly suggests its high metal tolerance capabilities. This experiment demonstrates that S. squarrosum is able to accumulate and tolerate a high amount of metals and feasibility of its application as bioindicator and remediator test species of metal-contaminated environment.

Mental Health Concerns for Indian Women

Abstract: This article studies the mental health problems of women, especially in the Indian context. As per World Health Organization (WHO) estimates, depression is expected to be the second largest contributor to disease burden by 2020, and with one in every three women worldwide being afflicted by common mental disorders including depression, the mental health of women is a serious issue indeed. While studying the psychological construct of mental health, we come to understand that it is deeply embedded within an individual’s social and socioeconomic relationships. Since women worldwide, and more so in India, face gender-based discrimination at every stage of their lives, their psychological well-being becomes a cause for great concern. This note attempts to explore the various risk and protective factors affecting the mental health of women. Considering the gravity of the matter, urgent remedial measures such as understanding the underlying causes of psychological distress among women, adopting a gender-sensiti...

Energy dependence of pre-equilibrium emission for the (p,xn) reactions in niobium

Abstract: Proton induced reactions have been studied in the energy region from ≈7.0 to 12.5 MeV for niobium, using the stacked foil activation technique followed by gamma ray spectroscopy. The excitation functions for the production of 93mMo, 93mNb and 89gZr have been determined. The experimental data have been compared with theoretical calculations based on compound reactions in statistical equilibrium as well as on pre-equilibrium reactions.

A QSAR study on novel series of carbonic anhydrase inhibitors hCA IX--tumor-associated (hypoxia).

Abstract: This paper presents results of QSAR (Quantitative Structure Activity Relationship) studies realized with the PRECLAV (Property Evaluation by Class Variables) software. The database contains 66 derivatives of aromatic benzene sulfonamides incorporating 1, 3, 5-triazine moieties, fluorophenyl sulfamates, S-substituted-2-mercaptobenzenesulfonamide and diazenylbenzenesulfonamides with clinically used CA inhibitors. For each molecule over 3600 descriptors were calculated using programs MOPAC, PRECLAV and DRAGON. A heuristic algorithm selects the best multiple linear regression (MLR) equation showed that the correlation between the observed values and the calculated values of activity is very good (N = 66, Se = 0.263, r(2) = 0.884, F = 92.98, r(2)(cv) = 0.859, Q = 0.794). The virtual molecular fragments that lead to a significant increase of the inhibitor activity of hCA IX are C(3)H(2)N(5)Cl, NH(2), C(6)H(4), C(3)H(5)N(6), COOH, and C(3)HN(6). The virtual fragment--HO, C(5)H(2)NO, C(3)HN(6), leads to a significant decrease of the inhibitor activity value. With a view to external validation, the calibration set includes 50 molecules (Se = 0.256, r(2) = 0.885, F = 69.501, r(2)(cv) = 0.852) and the validation set includes 16 molecules (Se = 0.111, r(2) = 0.87, F = 93.984). Identification of molecules in validation set with high estimated value of inhibitory activity of hCA IX is correct enough to have practical value, even if the calibration/validation set contains aromatic benzene sulfonamides incorporating 1,3,5-triazine moieties and fluor phenyl sulfamates derivatives with very different chemical structures.

Infectivity of Bufo melanostictus (Amphibia: Bufonidae) to Two New Species of Haematozoan Parasites from Rohilkhand, India

Abstract: Micro-haematotechniques (hanging drop preparations, microhaematocrit, permanent smears) on blood of Bufo melanostictus revealed 210 % prevalence of Trypanosoma bisalpurensis n sp (intensity 10–20/100 RBCs) and Hepatozoon gangwarii n sp (intensity 10–30/100 RBCs) The permanent preparations of the parasites were cyto-morpho-taxonomically compared with the previously described forms The characteristic ‘S’-shaped body, the unusual close proximity of the nucleus and kinetoplast, the slender and elongated body and a shortened free flagellum of the Trypanosoma species and the differential size, nuclear position and dimensions, nuclear displacement ratio, absence of capsule and gametocyte characteristics of Hepatozoon are regarded as novel identity of the parasites and are being reported as new species with specific characters as provided in this communication The displacement of the host nucleus is consequential due to Hepatozoon infection and is also described herein

Investigation of the influence of incomplete fusion on complete fusion of 16O induced reactions at moderate excitation energies

Abstract: An attempt has been made to investigate for the reaction dynamics leading to incomplete fusion (ICF) of heavy ions at moderate excitation energies, especially the influence of incomplete fusion on complete fusion (CF) of 16 O induced reactions at specific energies Excitation functions (EFs) of various reaction products populated via CF and/or ICF of 16 O projectile with 45 Sc target were measured at energies ≈3-7 MeV/nucleon, using recoil catcher technique followed by offline γ-ray spectroscopy The measured EFs were compared with theoretical values obtained using the statistical model code PACE4 The experimentally measured EFs were in general found to be in good agreement with the theoretical predictions for non α-emitting channels in the present target projectile system However, for α-emitting channels the measured EFs were higher than the predictions of the theoretical model codes, which may be credited to incomplete fusion reactions at these energies

Impact of exogenous application of Indole Acetic Acid on accumulation of heavy metal and antioxidants in wheat (Triticum aestivum L.) under sewage water irrigation

Abstract: A field experiment was conducted to study the activities of antioxidative enzymes SOD, CAT & GR, non-enzymatic antioxidants i.e. carotenoid & proline and uptake of heavy metals (Pb, Cr, Zn, Cu and Fe) in winter wheat (Triticum aestivum L.) variety PBW-343 grown under sewage water (SW) collected from Quilla channel of Bareilly city (U.P), India. Wheat was irrigated with two concentrations (50% and 100%) of sewage water along with exogenous application of 10 and 20 ppm Indole-3 Acetic Acid (IAA). Enzymatic and non-enzymatic antioxidant was significantly higher in 100% SW as compared to 50% SW. There was a significant (p<0.001) increase in carotenoid and proline content whereas decrease in uptake of toxic heavy metals was observed in wheat irrigated with SW+10 and 20 ppm IAA as compared to SW and control. Further, significant (p<0.001) decline in carotenoid and proline content was evident in 20 ppm IAA as compared to 10 ppm IAA in both the concentrations of SW. In contrast, under both the concentrations of SW, heavy metals especially Cr found to decrease (p<0.05) whereas significant decrease was also noticed in Zn, Cu and Fe uptake on application of 20 ppm IAA as compared to 10 ppm IAA and SW alone. Normal 0 false false false EN-IN X-NONE X-NONE

Mutual viscosity and NMR spin–lattice relaxation time in some polar molecules

Abstract: Present communication reports the experimental values of the NMR spin–lattice relaxation time (T 1) of 10 polar molecules and mutual viscosity ( ) of 2-fluorobenzaldehyde, 3-fluorobenzaldehyde and 4-fluorobenzaldehyde. The experimental values of T 1 have been correlated with the calculated value of T 1 obtained using different equations for the dielectric relaxation time ( ). It is concluded from this comparative study that the Murty equation is a useful representation of the dielectric relaxation phenomenon. It is also concluded that the mutual viscosity ( ) is a substitute for the resistance to the rotation of the individual solute molecule.

In Silico Modeling of Carbonic Anhydrase Inhibitor hCA IX-Tumor Associated (Hypoxia)

Abstract: From two QSAR studies realized with the PRECLAV computer program, the database of the series of aromatic benzene sulfonamides incorporating 1,3,5-triazine moieties derivative, give without outliers N = 59, Se = 02858, r 2 = 08734, r CV 2 = 08444, F = 745237 The virtual molecular fragments that lead to a significant increase of the inhibitor activity of CA IX are C3H2N5Cl, NH2, C3H5N6, CHO2, and C3HN6 The virtual fragment OH, C5H2NO, N atom, CHO2, C3HN6 leads to a significant decrease of the inhibitor activity value The CA IX inhibitor activity is favorably influenced by the size of the molecule With a view to external validation, the calibration set includes 46 molecules (Se = 0234, r 2 = 09114, F = 843447, r CV 2 = 08872) and the validation set includes 13 molecules (Se = 0279, r 2 = 08741, F = 569143, r CV 2 = 08246) Identification of molecules in validation set with high estimated value of inhibitory activity of CA IX is correct enough to have practical value, even if the calibration/validation set contains aromatic benzene sulfonamides incorporating 1,3,5-triazine moieties derivatives with very different chemical structures