sk sharma - Academia.edu (original) (raw)

Papers by sk sharma

Journal of Polymer Science: Polymer Physics Edition, 1984

Correction factors defined as the ratio of the true size parameter and the size parameter deduced... more Correction factors defined as the ratio of the true size parameter and the size parameter deduced from Fraunhofer diffraction theory are presented for weakly anisotropic transparent fibers. These correction factors enable the Fraunhofer diffraction approximation to be used for sizing weakly anisotropic fibers from light‐scattering measurements. Fibers in the diameter range 4–50 μm and refractive index range 1.45–1.56 are considered. It is shown that for fibers having birefringence −0.005 ≤ Δm ≤ 0.01, the diameters may be obtained to within 9% accuracy if the fiber diameter lies between 4 and 50 μm.

International Journal of Science and Research (IJSR)

Hemoglobinopathies are the most commonly encountered monogenic disorders of blood posing a major ... more Hemoglobinopathies are the most commonly encountered monogenic disorders of blood posing a major genetic and public health problem in Southeast Asia and the Indian subcontinent. Of the several abnormal hemoglobins so far identified, there are three variants – sickle cell (Hb S), hemoglobin E (Hb E) and hemoglobin D (Hb D), which are predominantly prevalent in India. Among these clinically important hemoglobinopathies, hemoglobin E (Hb E) is mostly restricted to the North eastern states of India with high gene frequency. Hb E disorders may be found in heterozygous (AE), homozygous (EE) and compound heterozygous states (e.g., Hb E with other abnormal hemoglobins or thalassemias) with widely variable clinical phenotypes. Studies suggest that there is a positive correlation of the βE-globin gene with malaria endemicity. Since northeast India is a holoendemic area for Plasmodium falciparum and other types of malaria, it is reasonable to suspect that malaria might be acting as a selective...

Biochemistry of Vitamin B6 and PQQ, 1994

In the past decade nontraditional functions for various vitamins which are not necessarily second... more In the past decade nontraditional functions for various vitamins which are not necessarily secondary arising out of cofactor function, have been recognized. From the notion of vitamin depletion and deficiency syndromes the newer concept that vitamins as chemicals do regulate or alter the rate of some metabolic reactions has found acceptance.

British journal of cancer, Jan 9, 2002

Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated se... more Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated selectively at the tumour site by an enzyme, which has been targeted to the tumour by an antibody (antibody-enzyme conjugate). Previous clinical trials have shown evidence of tumour response, however, the activated drug had a long half-life, which resulted in dose-limiting myelosuppression. Also, the targeting system, although giving high tumour to blood ratios of antibody-enzyme conjugate (10 000 : 1) required administration of a clearing antibody in addition to the antibody-enzyme conjugate. The purpose of this current study therefore was to attempt tumour targeting of the antibody-enzyme conjugate without the clearing antibody, and to investigate a new prodrug (bis-iodo phenol mustard, ZD2767P) whose activated form is highly potent and has a short half-life. Twenty-seven patients were treated with antibody-directed enzyme prodrug therapy using A5CP antibody-enzyme conjugate and ZD2767P ...

The Journal of communicable diseases, 1981

The Indian Journal of Pediatrics, 1990

Radionuclide gastro-esophageal scintigraphy was performed on 25 control and 183 children sufferin... more Radionuclide gastro-esophageal scintigraphy was performed on 25 control and 183 children suffering from recurrent lower respiratory tract infectior~. Gastro-esophageal reflux (GER) of varying grades was observed in 135 patients. The severity of clinical symptoms in the patients was found to be directly related to the severity of reflux observed in the radionuclide study. In some patients an attempt was also made to quantitate GER by calculating the Gastro-asophageal reflux index. The results of the scintigraphic study were correlated with the results of the other commonly used and more conventional Barium swallow and fluoroscopy study. Gastro-esophageal scintigraphy was found to be much superior in terms of sensitivity, specificity and accuracy in detecting GER. It was also possible to objectively evaluate and monitor response to treatment following conservative or corrective surgical therapy using the radionuclide technique. The results of the study demonstrated a remarkably high incidence of GER in the patients. Whether GER is the cause of recurrent lower respiratory tract infection or not is difficult to establish firmly. But within the perview of the study the association seems to be very strong and cannotbe easily ignored.

AIDS Research and Treatment, 2012

Objective. The increased use of antiretroviral therapy (ART) has reduced the morbidity and mortal... more Objective. The increased use of antiretroviral therapy (ART) has reduced the morbidity and mortality associated with HIV, adversely leading to the emergence of HIV drug resistance (HIVDR). In this study we aim to evaluate the prevalence of HIVDR mutations in ART-naive HIV-1 infected patients from northern India.Design. Analysis was performed using Viroseq genotyping system based on sequencing of entire protease and two-thirds of the Reverse Transcriptase (RT) region ofpolgene.Results. Seventy three chronic HIV-1 infected ART naïve patients eligible for first line ART were enrolled from April 2006 to August 2008. In 68 patients DNA was successfully amplified and sequencing was done. 97% of HIV-1 strains belonged to subtype C, and one each to subtype A1 and subtype B. The overall prevalence of primary DRMs was 2.9% [2/68, 95% confidence interval (CI), 0.3%–10.2%]. One patient had a major RT mutation M184V, known to confer resistance to lamivudine, and another had a major protease inhi...

The Indian Journal of Pediatrics, 1973

Physical Review C, 1981

The role played by the ¹gââ orbital vis-a-vis the structure of the recently observed high-spin y... more The role played by the ¹gââ orbital vis-a-vis the structure of the recently observed high-spin yrast cascade in ⁶°Ni is examined. The anomalous high-spin sequence is correctly reproduced. A number of electromagnetic transitions are predicted.

Pharmaceutical Biology, 1998

Crude ethanol extracts (CEE) of dried leaves (CEE1), fresh leaves (CEE2), dried petioles (CEE3) a... more Crude ethanol extracts (CEE) of dried leaves (CEE1), fresh leaves (CEE2), dried petioles (CEE3) and stem bark (CEE4) of Gliricidia sepium were investigated for their toxic properties on the late third instar larvae of Anopheles stephansi, Aedes aegypti and Culex quinquefasciatus. The results indicate that all the CEEs are toxic to the larvae of the three species, causing 100% mortality at or below a dosage of 16,000 ppm. Although the mortality rate is dose-dependent, the larvae of different species exhibit genetic variability with respect to their tolerance at lower doses of CEE. It is likely that the toxicity, at least in some cases, could be due to more than one toxic principle. The findings also suggest that toxic principles vary quantitatively and/or qualitatively in different organs of the plant. Overall, CEE2 shows a higher toxicity and CEE3 shows a weaker toxicity compared to CEEs from fresh leaves and bark.

Journal of the Korean Physical Society, 2013

Hydrogenated amorphous silicon thin films manufactured by plasma deposition techniques are widely... more Hydrogenated amorphous silicon thin films manufactured by plasma deposition techniques are widely used in electronic and optoelectronic devices. The optical and electrical properties of undoped and doped hydrogenated amorphous silicon (a-Si:H) thin films determine the importance and characteristics of the final film structure of practical devices. In particular, a-Si:H thin film solar cells and optical sensors have many industrial and technical advantages, such as being light weight, low cost, and having a large deposition area. The a-Si:H thin film is one of the candidates for flexible solar cells for use in space. This article reviews the optical and electrical properties of double donor Se-and S-doped a-Si:H thin films, which can be considered as an alternative to wide bandgap absorbing layers in the next generation of optoelectronic devices.

Journal of Physics: Condensed Matter, 2007

In situ x-ray diffraction studies on α-cristobalite GaPO4 have found that the orthorhombic α-cris... more In situ x-ray diffraction studies on α-cristobalite GaPO4 have found that the orthorhombic α-cristobalite GaPO4 (I) transforms into a monoclinic phase (II) at about 2GPa, then to the VCrO4-type orthorhombic phase (III) at 4GPa, which persists to 52 GPa, and no further transformation was observed. The volume changes for (I)–(II) and (II)–(III) transitions are ∼<1% and 17%, respectively, at the transition pressure. Upon releasing the pressure to atmospheric pressure, the orthorhombic phase (III) either reverses back to the phase (I) or persists as the metastable phase, depending upon the loading process. By fitting the P–V data to the Murnaghan equation of state, we obtained values of the zero-pressure bulk modulus (K0) and its pressure derivative (K0′) at 12.1 2.1GPa and 11.5 3.5 for phase (I), and 144.1 6.1GPa and 5.2 0.4 for phase (III).

Journal of Neuroscience Research, 1987

Incubation of C6‐BU1 glioma cells in the presence of isoproterenol and Ro20‐1724—a potent cAMP ph... more Incubation of C6‐BU1 glioma cells in the presence of isoproterenol and Ro20‐1724—a potent cAMP phosphodiesterase inhibitor—results in a transient increase in intracellular cAMP levels, followed by a rapid efflux of cyclic AMP from the cells into the media. Two distinct types of morphological changes could be seen: (1) rounded cell bodies with multipolar processes and beadings after 30 minutes of incubation—this period coincides with a 70–80‐fold increase in intracellular cAMP levels, and (2) elongated cell bodies with extended bipolar processes after 24–48 hours. By this time the intracellular cAMP concentration drpped to a low level, which was only three‐ to four fold higher than that in control. The transient increase in intracellular cAMP concentration results in retardation of cell growth, diminished uptake of 3H‐2‐deoxyglucose, and abolition of enhanced synthesis of cyclic AMP by concanavalin A.

Journal of Neural Transmission, 1993

Microinjections of the neuroexcitotoxin, domoic acid (DOM), in the ipsilateral rat hippocampal CA... more Microinjections of the neuroexcitotoxin, domoic acid (DOM), in the ipsilateral rat hippocampal CA-3 region, induced generalized electrical seizure discharge activity, characterized by spikes and waves, followed by intermittent burst discharges. Computerized EEG analysis exhibited relative dominance of delta and theta and reductions in alpha and beta activities during domoic acid epileptogenesis. Seizure discharge activity was attenuated by the microinjection of the 5-HT~A agonist, 8-hydroxy-2-(di-N-propylamino)tetralin(8-(OH)-DPAT) and augmented by the specific 5-HT1A antagonist, spiroxatrine in the contralateral hippocampal CA-3 region. Neuronal recovery following 8-(OH)-DPAT was associated with significant reductions in the relative dominance of delta and theta and increases in the alpha and beta activities. The results suggest that activation of serotonergic 5-HT~A receptor in the hippocampus has a neuroprotective action.

Journal of Modern Optics, 1992

The derivation of the anomalous diffraction approximation from Mie theory has been re-examined. T... more The derivation of the anomalous diffraction approximation from Mie theory has been re-examined. The usual requirement ¦m − 1¦ ≪ 1, m being the relative refractive index of the scatterer, is shown to be over-restrictive. A more appropriate requirement is found to be ¦m − 1¦ ≪ ¦m + 1¦. The relationship between the anomalous diffraction approximation and another m→1

Journal of Materials Science, 2004

ABSTRACT In this paper thermally stimulated luminescence (TSL) studies of BaB4O7 compound are rep... more ABSTRACT In this paper thermally stimulated luminescence (TSL) studies of BaB4O7 compound are reported for the first time. The polycrystalline sample of BaB4O7 was prepared by a melting method and the formation of the BaB4O7 compound was confirmed by an X-ray diffraction study. The compound has orthorhombic structure at room temperature. The TSL glow curves of BaB4O7 compound when heated at a constant heating rate of 4C/s exhibit two thermoluminescence (TL) glow peaks at 110 and 150C followed by a shoulder around 210C. The trapping parameters associated with the prominent glow peak of BaB4O7 are reported using isothermal luminescence decay method (ILDM). As a check the trap parameters are also calculated by glow curve shape (Chen's) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods.

Journal of Fluorescence, 2013

This paper reports the structural and optical properties of rare earth doped and codoped yttrium ... more This paper reports the structural and optical properties of rare earth doped and codoped yttrium oxide nanophosphors. Dysprosium (Dy 3+) and Terbium (Tb 3+) doped and codoped yttrium oxide (Y 2 O 3) phosphors were prepared by combustion synthesis method and subsequently annealed to high temperature to eliminate the hydroxyl group (−OH) and to get more crystallinity. The formation of compounds was confirmed by the X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR). The diffuse reflectance spectra (DRS) of doped and codoped Y 2 O 3 powder phosphors were measured and it is observed that the absorption edge of the doped samples is shifted towards blue region with respect to undoped sample. The bandgap of the prepared samples were evaluated with the help of Kubelka-Munk function using Diffuse Reflectance Spectra (DRS) and an increase in bandgap was observed with the decrease in crystallite size. A strong characteristics emission from Tb 3+ and Dy 3+ ions was identified and the influence of doping concentration and annealing temperature on photoluminescence properties was systematically studied. Transfer of energy was observed in dysprosium-terbium codoped Y 2 O 3 nanophosphor at room temperature from Dy 3+ ions toTb 3+ ions.

Journal of Biosciences, 2006

Anopheles fluviatilis and An. minimus complexes,each comprising of at least three sibling species... more Anopheles fluviatilis and An. minimus complexes,each comprising of at least three sibling species, are closely related and important malaria vectors in Oriental Region. Recently An. fluviatilis species S, which is a highly efficient malaria vector in India, has been made conspecific with An. minimus species C (senior synonym) on the basis of homology in 335 base pair nucleotide sequence of D3 domain of 28S ribosomal DNA (rDNA). We examined the conspecificity of these two nominal species by obtaining and analysing the DNA sequences of nuclear ribosomal loci internal transcribed spacer 2 (ITS2) and D2-D3 domain of 28S rDNA (28S-D2/D3) from those of An. fluviatilis S and An. minimus C. We found that the sequences of An. fluviatilis S are appreciably different from those of An. minimus C with pair-wise distance (Kimura-2-parametre model)of 3.6 and 0.7%for loci ITS2 and 28S-D2/D3, respectively. Pair-wise distance and phylogenetic analyses using ITS2 sequences of members of Minimus and Fluviatilis Complexes revealed that An. fluviatilis S is distantly related to An. minimus C as compared to any other members of the Fluviatilis Complex. These findings suggest that the two nominal species, An. fluviatilis S and An. minimus C, do not merit synonymy. The study also confirms that the reported species An. fluviatilis X is synonym with species S.

Journal of Asthma, 1987

This article describes the immediate effect of verapamil, a calcium antagonist, on pulmonary func... more This article describes the immediate effect of verapamil, a calcium antagonist, on pulmonary functions in bronchial asthma. The effect of oral administration of 80 mg of verapamil or placebo was studied in a randomized double-blind manner in 30 extrinsic asthmatic subjects. No significant bronchodilator effect was observed with verapamil administration. There were no significant changes in heart rate and blood pressure after verapamil.

Journal of Polymer Science: Polymer Physics Edition, 1984

Correction factors defined as the ratio of the true size parameter and the size parameter deduced... more Correction factors defined as the ratio of the true size parameter and the size parameter deduced from Fraunhofer diffraction theory are presented for weakly anisotropic transparent fibers. These correction factors enable the Fraunhofer diffraction approximation to be used for sizing weakly anisotropic fibers from light‐scattering measurements. Fibers in the diameter range 4–50 μm and refractive index range 1.45–1.56 are considered. It is shown that for fibers having birefringence −0.005 ≤ Δm ≤ 0.01, the diameters may be obtained to within 9% accuracy if the fiber diameter lies between 4 and 50 μm.

International Journal of Science and Research (IJSR)

Hemoglobinopathies are the most commonly encountered monogenic disorders of blood posing a major ... more Hemoglobinopathies are the most commonly encountered monogenic disorders of blood posing a major genetic and public health problem in Southeast Asia and the Indian subcontinent. Of the several abnormal hemoglobins so far identified, there are three variants – sickle cell (Hb S), hemoglobin E (Hb E) and hemoglobin D (Hb D), which are predominantly prevalent in India. Among these clinically important hemoglobinopathies, hemoglobin E (Hb E) is mostly restricted to the North eastern states of India with high gene frequency. Hb E disorders may be found in heterozygous (AE), homozygous (EE) and compound heterozygous states (e.g., Hb E with other abnormal hemoglobins or thalassemias) with widely variable clinical phenotypes. Studies suggest that there is a positive correlation of the βE-globin gene with malaria endemicity. Since northeast India is a holoendemic area for Plasmodium falciparum and other types of malaria, it is reasonable to suspect that malaria might be acting as a selective...

Biochemistry of Vitamin B6 and PQQ, 1994

In the past decade nontraditional functions for various vitamins which are not necessarily second... more In the past decade nontraditional functions for various vitamins which are not necessarily secondary arising out of cofactor function, have been recognized. From the notion of vitamin depletion and deficiency syndromes the newer concept that vitamins as chemicals do regulate or alter the rate of some metabolic reactions has found acceptance.

British journal of cancer, Jan 9, 2002

Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated se... more Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated selectively at the tumour site by an enzyme, which has been targeted to the tumour by an antibody (antibody-enzyme conjugate). Previous clinical trials have shown evidence of tumour response, however, the activated drug had a long half-life, which resulted in dose-limiting myelosuppression. Also, the targeting system, although giving high tumour to blood ratios of antibody-enzyme conjugate (10 000 : 1) required administration of a clearing antibody in addition to the antibody-enzyme conjugate. The purpose of this current study therefore was to attempt tumour targeting of the antibody-enzyme conjugate without the clearing antibody, and to investigate a new prodrug (bis-iodo phenol mustard, ZD2767P) whose activated form is highly potent and has a short half-life. Twenty-seven patients were treated with antibody-directed enzyme prodrug therapy using A5CP antibody-enzyme conjugate and ZD2767P ...

The Journal of communicable diseases, 1981

The Indian Journal of Pediatrics, 1990

Radionuclide gastro-esophageal scintigraphy was performed on 25 control and 183 children sufferin... more Radionuclide gastro-esophageal scintigraphy was performed on 25 control and 183 children suffering from recurrent lower respiratory tract infectior~. Gastro-esophageal reflux (GER) of varying grades was observed in 135 patients. The severity of clinical symptoms in the patients was found to be directly related to the severity of reflux observed in the radionuclide study. In some patients an attempt was also made to quantitate GER by calculating the Gastro-asophageal reflux index. The results of the scintigraphic study were correlated with the results of the other commonly used and more conventional Barium swallow and fluoroscopy study. Gastro-esophageal scintigraphy was found to be much superior in terms of sensitivity, specificity and accuracy in detecting GER. It was also possible to objectively evaluate and monitor response to treatment following conservative or corrective surgical therapy using the radionuclide technique. The results of the study demonstrated a remarkably high incidence of GER in the patients. Whether GER is the cause of recurrent lower respiratory tract infection or not is difficult to establish firmly. But within the perview of the study the association seems to be very strong and cannotbe easily ignored.

AIDS Research and Treatment, 2012

Objective. The increased use of antiretroviral therapy (ART) has reduced the morbidity and mortal... more Objective. The increased use of antiretroviral therapy (ART) has reduced the morbidity and mortality associated with HIV, adversely leading to the emergence of HIV drug resistance (HIVDR). In this study we aim to evaluate the prevalence of HIVDR mutations in ART-naive HIV-1 infected patients from northern India.Design. Analysis was performed using Viroseq genotyping system based on sequencing of entire protease and two-thirds of the Reverse Transcriptase (RT) region ofpolgene.Results. Seventy three chronic HIV-1 infected ART naïve patients eligible for first line ART were enrolled from April 2006 to August 2008. In 68 patients DNA was successfully amplified and sequencing was done. 97% of HIV-1 strains belonged to subtype C, and one each to subtype A1 and subtype B. The overall prevalence of primary DRMs was 2.9% [2/68, 95% confidence interval (CI), 0.3%–10.2%]. One patient had a major RT mutation M184V, known to confer resistance to lamivudine, and another had a major protease inhi...

The Indian Journal of Pediatrics, 1973

Physical Review C, 1981

The role played by the ¹gââ orbital vis-a-vis the structure of the recently observed high-spin y... more The role played by the ¹gââ orbital vis-a-vis the structure of the recently observed high-spin yrast cascade in ⁶°Ni is examined. The anomalous high-spin sequence is correctly reproduced. A number of electromagnetic transitions are predicted.

Pharmaceutical Biology, 1998

Crude ethanol extracts (CEE) of dried leaves (CEE1), fresh leaves (CEE2), dried petioles (CEE3) a... more Crude ethanol extracts (CEE) of dried leaves (CEE1), fresh leaves (CEE2), dried petioles (CEE3) and stem bark (CEE4) of Gliricidia sepium were investigated for their toxic properties on the late third instar larvae of Anopheles stephansi, Aedes aegypti and Culex quinquefasciatus. The results indicate that all the CEEs are toxic to the larvae of the three species, causing 100% mortality at or below a dosage of 16,000 ppm. Although the mortality rate is dose-dependent, the larvae of different species exhibit genetic variability with respect to their tolerance at lower doses of CEE. It is likely that the toxicity, at least in some cases, could be due to more than one toxic principle. The findings also suggest that toxic principles vary quantitatively and/or qualitatively in different organs of the plant. Overall, CEE2 shows a higher toxicity and CEE3 shows a weaker toxicity compared to CEEs from fresh leaves and bark.

Journal of the Korean Physical Society, 2013

Hydrogenated amorphous silicon thin films manufactured by plasma deposition techniques are widely... more Hydrogenated amorphous silicon thin films manufactured by plasma deposition techniques are widely used in electronic and optoelectronic devices. The optical and electrical properties of undoped and doped hydrogenated amorphous silicon (a-Si:H) thin films determine the importance and characteristics of the final film structure of practical devices. In particular, a-Si:H thin film solar cells and optical sensors have many industrial and technical advantages, such as being light weight, low cost, and having a large deposition area. The a-Si:H thin film is one of the candidates for flexible solar cells for use in space. This article reviews the optical and electrical properties of double donor Se-and S-doped a-Si:H thin films, which can be considered as an alternative to wide bandgap absorbing layers in the next generation of optoelectronic devices.

Journal of Physics: Condensed Matter, 2007

In situ x-ray diffraction studies on α-cristobalite GaPO4 have found that the orthorhombic α-cris... more In situ x-ray diffraction studies on α-cristobalite GaPO4 have found that the orthorhombic α-cristobalite GaPO4 (I) transforms into a monoclinic phase (II) at about 2GPa, then to the VCrO4-type orthorhombic phase (III) at 4GPa, which persists to 52 GPa, and no further transformation was observed. The volume changes for (I)–(II) and (II)–(III) transitions are ∼<1% and 17%, respectively, at the transition pressure. Upon releasing the pressure to atmospheric pressure, the orthorhombic phase (III) either reverses back to the phase (I) or persists as the metastable phase, depending upon the loading process. By fitting the P–V data to the Murnaghan equation of state, we obtained values of the zero-pressure bulk modulus (K0) and its pressure derivative (K0′) at 12.1 2.1GPa and 11.5 3.5 for phase (I), and 144.1 6.1GPa and 5.2 0.4 for phase (III).

Journal of Neuroscience Research, 1987

Incubation of C6‐BU1 glioma cells in the presence of isoproterenol and Ro20‐1724—a potent cAMP ph... more Incubation of C6‐BU1 glioma cells in the presence of isoproterenol and Ro20‐1724—a potent cAMP phosphodiesterase inhibitor—results in a transient increase in intracellular cAMP levels, followed by a rapid efflux of cyclic AMP from the cells into the media. Two distinct types of morphological changes could be seen: (1) rounded cell bodies with multipolar processes and beadings after 30 minutes of incubation—this period coincides with a 70–80‐fold increase in intracellular cAMP levels, and (2) elongated cell bodies with extended bipolar processes after 24–48 hours. By this time the intracellular cAMP concentration drpped to a low level, which was only three‐ to four fold higher than that in control. The transient increase in intracellular cAMP concentration results in retardation of cell growth, diminished uptake of 3H‐2‐deoxyglucose, and abolition of enhanced synthesis of cyclic AMP by concanavalin A.

Journal of Neural Transmission, 1993

Microinjections of the neuroexcitotoxin, domoic acid (DOM), in the ipsilateral rat hippocampal CA... more Microinjections of the neuroexcitotoxin, domoic acid (DOM), in the ipsilateral rat hippocampal CA-3 region, induced generalized electrical seizure discharge activity, characterized by spikes and waves, followed by intermittent burst discharges. Computerized EEG analysis exhibited relative dominance of delta and theta and reductions in alpha and beta activities during domoic acid epileptogenesis. Seizure discharge activity was attenuated by the microinjection of the 5-HT~A agonist, 8-hydroxy-2-(di-N-propylamino)tetralin(8-(OH)-DPAT) and augmented by the specific 5-HT1A antagonist, spiroxatrine in the contralateral hippocampal CA-3 region. Neuronal recovery following 8-(OH)-DPAT was associated with significant reductions in the relative dominance of delta and theta and increases in the alpha and beta activities. The results suggest that activation of serotonergic 5-HT~A receptor in the hippocampus has a neuroprotective action.

Journal of Modern Optics, 1992

The derivation of the anomalous diffraction approximation from Mie theory has been re-examined. T... more The derivation of the anomalous diffraction approximation from Mie theory has been re-examined. The usual requirement ¦m − 1¦ ≪ 1, m being the relative refractive index of the scatterer, is shown to be over-restrictive. A more appropriate requirement is found to be ¦m − 1¦ ≪ ¦m + 1¦. The relationship between the anomalous diffraction approximation and another m→1

Journal of Materials Science, 2004

ABSTRACT In this paper thermally stimulated luminescence (TSL) studies of BaB4O7 compound are rep... more ABSTRACT In this paper thermally stimulated luminescence (TSL) studies of BaB4O7 compound are reported for the first time. The polycrystalline sample of BaB4O7 was prepared by a melting method and the formation of the BaB4O7 compound was confirmed by an X-ray diffraction study. The compound has orthorhombic structure at room temperature. The TSL glow curves of BaB4O7 compound when heated at a constant heating rate of 4C/s exhibit two thermoluminescence (TL) glow peaks at 110 and 150C followed by a shoulder around 210C. The trapping parameters associated with the prominent glow peak of BaB4O7 are reported using isothermal luminescence decay method (ILDM). As a check the trap parameters are also calculated by glow curve shape (Chen's) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods.

Journal of Fluorescence, 2013

This paper reports the structural and optical properties of rare earth doped and codoped yttrium ... more This paper reports the structural and optical properties of rare earth doped and codoped yttrium oxide nanophosphors. Dysprosium (Dy 3+) and Terbium (Tb 3+) doped and codoped yttrium oxide (Y 2 O 3) phosphors were prepared by combustion synthesis method and subsequently annealed to high temperature to eliminate the hydroxyl group (−OH) and to get more crystallinity. The formation of compounds was confirmed by the X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR). The diffuse reflectance spectra (DRS) of doped and codoped Y 2 O 3 powder phosphors were measured and it is observed that the absorption edge of the doped samples is shifted towards blue region with respect to undoped sample. The bandgap of the prepared samples were evaluated with the help of Kubelka-Munk function using Diffuse Reflectance Spectra (DRS) and an increase in bandgap was observed with the decrease in crystallite size. A strong characteristics emission from Tb 3+ and Dy 3+ ions was identified and the influence of doping concentration and annealing temperature on photoluminescence properties was systematically studied. Transfer of energy was observed in dysprosium-terbium codoped Y 2 O 3 nanophosphor at room temperature from Dy 3+ ions toTb 3+ ions.

Journal of Biosciences, 2006

Anopheles fluviatilis and An. minimus complexes,each comprising of at least three sibling species... more Anopheles fluviatilis and An. minimus complexes,each comprising of at least three sibling species, are closely related and important malaria vectors in Oriental Region. Recently An. fluviatilis species S, which is a highly efficient malaria vector in India, has been made conspecific with An. minimus species C (senior synonym) on the basis of homology in 335 base pair nucleotide sequence of D3 domain of 28S ribosomal DNA (rDNA). We examined the conspecificity of these two nominal species by obtaining and analysing the DNA sequences of nuclear ribosomal loci internal transcribed spacer 2 (ITS2) and D2-D3 domain of 28S rDNA (28S-D2/D3) from those of An. fluviatilis S and An. minimus C. We found that the sequences of An. fluviatilis S are appreciably different from those of An. minimus C with pair-wise distance (Kimura-2-parametre model)of 3.6 and 0.7%for loci ITS2 and 28S-D2/D3, respectively. Pair-wise distance and phylogenetic analyses using ITS2 sequences of members of Minimus and Fluviatilis Complexes revealed that An. fluviatilis S is distantly related to An. minimus C as compared to any other members of the Fluviatilis Complex. These findings suggest that the two nominal species, An. fluviatilis S and An. minimus C, do not merit synonymy. The study also confirms that the reported species An. fluviatilis X is synonym with species S.

Journal of Asthma, 1987

This article describes the immediate effect of verapamil, a calcium antagonist, on pulmonary func... more This article describes the immediate effect of verapamil, a calcium antagonist, on pulmonary functions in bronchial asthma. The effect of oral administration of 80 mg of verapamil or placebo was studied in a randomized double-blind manner in 30 extrinsic asthmatic subjects. No significant bronchodilator effect was observed with verapamil administration. There were no significant changes in heart rate and blood pressure after verapamil.