This study details the evolution of morphologies in the Si1-xGex/Si system, under kinetically con... more This study details the evolution of morphologies in the Si1-xGex/Si system, under kinetically controlled conditions of 550 °C growth temperature and 1 Å/s growth rate. We find that, with increasing film thickness and Ge fraction, a series of three-dimensional structures develop, starting from pits, and leading to quantum fortresses and ridges. The quantum fortress structures are of special significance because
The embryos of a cultivated tetraploid peanut (Arachis hypogaea), a wild diploid species (A. vill... more The embryos of a cultivated tetraploid peanut (Arachis hypogaea), a wild diploid species (A. villosa), and their hybrid embryos, which generally abort in nature, were cultured in vitro and the plants have been successfully transferred to the soil. The hybrids showed triploid chromosome number (3x=30). The significance of wide hybridization in peanut-improvement programs is discussed.
This study reports laboratory measurements of particle size distributions, cloud condensation nuc... more This study reports laboratory measurements of particle size distributions, cloud condensation nuclei (CCN) activity, and droplet activation kinetics of wet generated aerosols from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. The dependence of critical supersaturation, sc, on particle dry diameter, Ddry, is used to characterize particle-water interactions and assess the ability of Frenkel-Halsey-Hill adsorption activation theory (FHH-AT) and Köhler theory (KT) to describe the CCN activity of the considered samples. Regional dust samples produce unimodal size distributions with particle sizes as small as 40 nm, CCN activation consistent with KT, and exhibit hygroscopicity similar to inorganic salts. Clays and minerals produce a bimodal size distribution; the CCN activity of the smaller mode is consistent with KT, while the larger mode is less hydrophilic, follows activation by FHH-AT, and displays almost identical CCN activity to dry generated dust. Ion Chromatography (IC) analysis performed on regional dust samples indicates a soluble fraction that cannot explain the CCN activity of dry or wet generated dust. A mass balance and hygroscopicity closure suggests that the small amount of ions (of low solubility compounds like calcite) present in the dry dust dissolve in the aqueous suspension during the wet generation process and give rise to the observed small hygroscopic mode. Overall these results identify an artifact that may question the atmospheric relevance of dust CCN activity studies using the wet generation method. Based on a threshold droplet growth analysis, wet generated mineral aerosols display similar activation kinetics compared to ammonium sulfate calibration aerosol. Finally, a unified CCN activity framework that accounts for concurrent effects of solute and adsorption is developed to describe the CCN activity of aged or hygroscopic dusts.
Dust and black carbon aerosol have long been known to exert potentially important and diverse imp... more Dust and black carbon aerosol have long been known to exert potentially important and diverse impacts on cloud droplet formation. Most studies to date focus on the soluble fraction of these particles, and overlook interactions of the insoluble fraction with water vapor (even if known to be hydrophilic). To address this gap, we developed a new parameterization that considers cloud droplet formation within an ascending air parcel containing insoluble (but wettable) particles externally mixed with aerosol containing an appreciable soluble fraction. Activation of particles with a soluble fraction is described through well-established Köhler theory, while the activation of hydrophilic insoluble particles is treated by "adsorption-activation" theory. In the latter, water vapor is adsorbed onto insoluble particles, the activity of which is described by a multilayer Frenkel-Halsey-Hill (FHH) adsorption isotherm modified to account for particle curvature. We further develop FHH activation theory to i) find combinations of the adsorption parameters A FHH , B FHH which yield atmospherically-relevant behavior, and, ii) express activation properties (critical supersaturation) that follow a simple power law with respect to dry particle diameter.
A multiobjective control problem is introduced. The definition of invexity for continuous functio... more A multiobjective control problem is introduced. The definition of invexity for continuous functions is extended to ρ-invexity, ρ-pseudoinvexity, and ρ-quasi-invexity. Duality results are established for Wolfe as well as Mond-Wier type duals.
A gradient, reversed-phase liquid chromatographic (RP-LC) method was developed for the quantitati... more A gradient, reversed-phase liquid chromatographic (RP-LC) method was developed for the quantitative determination of rizatriptan benzoate, used to treat relieves migraine headache symptoms. The developed method can be also employed for the related substance determination in bulk samples. Forced degradation studies were performed on bulk sample of rizatriptan benzoate using acid (0.5 N hydrochloric acid), base (0.1 N sodium hydroxide), oxidation (3.0% hydrogen peroxide), water hydrolysis, heat (60 degrees C) and photolytic degradation. Mild degradation of the drug substance was observed in base hydrolysis and considerable degradation observed during oxidative stress. The chromatographic method was fine tuned using the samples generated from forced degradation studies. Good resolution between the peaks corresponds to degradation products and the analyte was achieved on Agilent Zorbax SB-CN (250 mm x 4.6 mm, 5 microm) column. The mobile phase consists of a mixture of aqueous potassium di hydrogen ortho phosphate (pH 3.4), acetonitrile and methanol. The stress sample solutions were assayed against the qualified reference standard of rizatriptan benzoate and the mass balance in each case was close to 99.7% indicating that the developed method is stability indicating. Validation of the developed method was carried out as per ICH requirements.
We have evaluated the long-term outcome of excision, aspiration and no treatment of dorsal wrist ... more We have evaluated the long-term outcome of excision, aspiration and no treatment of dorsal wrist ganglia prospectively in 236 (83%) of 283 patients who responded to a postal questionnaire at a mean of 70 months. The resolution of symptoms was similar between the treatment groups (p>0.3). Pain and unsightliness improved in all three treatment groups. The prevalence of weakness and stiffness altered only slightly in all three treatment groups. More patients with a recurrent, or persistent ganglion complained of pain, stiffness and unsightliness (p<0.0001). Patient satisfaction was higher after surgical excision (p<0.0001), even if the ganglion recurred. Twenty-three of 55 (58%) untreated ganglia resolved spontaneously. The recurrence rate was 58% (45/78) and 39% (40/103) following aspiration and excision, respectively. Eight out of 103 patients had complications following surgery. In this study, neither excision nor aspiration provided significant long-term benefit over no treatment.
The dynamic behavior of two types of sandwich composites made of E-Glass Vinyl-Ester (EVE) facesh... more The dynamic behavior of two types of sandwich composites made of E-Glass Vinyl-Ester (EVE) facesheets and Corecell™ A-series foam with a polyurea interlayer was studied using a shock tube apparatus. The materials, as well as the core layer arrangements, were identical, with the only difference arising in the location of the polyurea interlayer. The foam core itself was layered with monotonically increasing wave impedance of the core layers, with the lowest wave impedance facing the shock loading. For configuration 1, the polyurea interlayer was placed behind the front facesheet, in front of the foam core, while in configuration 2 it was placed behind the foam core, in front of the back facesheet. A high-speed side-view camera, along with a high-speed back-view 3-D Digital Image Correlation (DIC) system, was utilized to capture the real time deformation process as well as mechanisms of failure. Post mortem analysis was also carried out to evaluate the overall blast performance of these two configurations. The results indicated that applying polyurea behind the foam core and in front of the back facesheet will reduce the back face deflection, particle velocity, and in-plane strain, thus improving the overall blast performance and maintaining structural integrity.
The doctors are vulnerable to substance abuse/addiction due to their ready accessibility to the s... more The doctors are vulnerable to substance abuse/addiction due to their ready accessibility to the substances of abuse. There is higher percentage use of alcohol, tranquillisers and psychedelics among medical students, and dependence rates are 5% for medical students and 3% for doctors. Majority of the substance-abusing doctors are graduates, belong to medicine speciality (21%) and majority of them prescribe drugs to themselves (37%). The consultants experience more substance related complications, despite having late age of onset of alcohol and substance dependence, less number of concomitant substance abuse and less career handicap. Stress (situational, personal and professional), medical student abuse and family history of alcoholism are the major risk factors. Despite paucity of studies in Indian population, substance use is reported between 32.5% to as high as 81.2% among medical students, intems and house physicians. In spite of the treatment dilemmas, the physicians do respond favourably to treatment. These findings have implications in planning preventive and interventional strategies for this professional group.
Lipid peroxides are considered to be the initiation factor for atherosclerosis. Present study dep... more Lipid peroxides are considered to be the initiation factor for atherosclerosis. Present study depicts that L-carnitine treatment (300 mg/kg body weight/day) for 7 and 14 days caused significant reduction in the tissue lipid peroxidations. It also shows marked improvement in the antioxidant status. By this way carnitine maintain the normal function of the cells.
This study details the evolution of morphologies in the Si1-xGex/Si system, under kinetically con... more This study details the evolution of morphologies in the Si1-xGex/Si system, under kinetically controlled conditions of 550 °C growth temperature and 1 Å/s growth rate. We find that, with increasing film thickness and Ge fraction, a series of three-dimensional structures develop, starting from pits, and leading to quantum fortresses and ridges. The quantum fortress structures are of special significance because
The embryos of a cultivated tetraploid peanut (Arachis hypogaea), a wild diploid species (A. vill... more The embryos of a cultivated tetraploid peanut (Arachis hypogaea), a wild diploid species (A. villosa), and their hybrid embryos, which generally abort in nature, were cultured in vitro and the plants have been successfully transferred to the soil. The hybrids showed triploid chromosome number (3x=30). The significance of wide hybridization in peanut-improvement programs is discussed.
This study reports laboratory measurements of particle size distributions, cloud condensation nuc... more This study reports laboratory measurements of particle size distributions, cloud condensation nuclei (CCN) activity, and droplet activation kinetics of wet generated aerosols from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. The dependence of critical supersaturation, sc, on particle dry diameter, Ddry, is used to characterize particle-water interactions and assess the ability of Frenkel-Halsey-Hill adsorption activation theory (FHH-AT) and Köhler theory (KT) to describe the CCN activity of the considered samples. Regional dust samples produce unimodal size distributions with particle sizes as small as 40 nm, CCN activation consistent with KT, and exhibit hygroscopicity similar to inorganic salts. Clays and minerals produce a bimodal size distribution; the CCN activity of the smaller mode is consistent with KT, while the larger mode is less hydrophilic, follows activation by FHH-AT, and displays almost identical CCN activity to dry generated dust. Ion Chromatography (IC) analysis performed on regional dust samples indicates a soluble fraction that cannot explain the CCN activity of dry or wet generated dust. A mass balance and hygroscopicity closure suggests that the small amount of ions (of low solubility compounds like calcite) present in the dry dust dissolve in the aqueous suspension during the wet generation process and give rise to the observed small hygroscopic mode. Overall these results identify an artifact that may question the atmospheric relevance of dust CCN activity studies using the wet generation method. Based on a threshold droplet growth analysis, wet generated mineral aerosols display similar activation kinetics compared to ammonium sulfate calibration aerosol. Finally, a unified CCN activity framework that accounts for concurrent effects of solute and adsorption is developed to describe the CCN activity of aged or hygroscopic dusts.
Dust and black carbon aerosol have long been known to exert potentially important and diverse imp... more Dust and black carbon aerosol have long been known to exert potentially important and diverse impacts on cloud droplet formation. Most studies to date focus on the soluble fraction of these particles, and overlook interactions of the insoluble fraction with water vapor (even if known to be hydrophilic). To address this gap, we developed a new parameterization that considers cloud droplet formation within an ascending air parcel containing insoluble (but wettable) particles externally mixed with aerosol containing an appreciable soluble fraction. Activation of particles with a soluble fraction is described through well-established Köhler theory, while the activation of hydrophilic insoluble particles is treated by "adsorption-activation" theory. In the latter, water vapor is adsorbed onto insoluble particles, the activity of which is described by a multilayer Frenkel-Halsey-Hill (FHH) adsorption isotherm modified to account for particle curvature. We further develop FHH activation theory to i) find combinations of the adsorption parameters A FHH , B FHH which yield atmospherically-relevant behavior, and, ii) express activation properties (critical supersaturation) that follow a simple power law with respect to dry particle diameter.
A multiobjective control problem is introduced. The definition of invexity for continuous functio... more A multiobjective control problem is introduced. The definition of invexity for continuous functions is extended to ρ-invexity, ρ-pseudoinvexity, and ρ-quasi-invexity. Duality results are established for Wolfe as well as Mond-Wier type duals.
A gradient, reversed-phase liquid chromatographic (RP-LC) method was developed for the quantitati... more A gradient, reversed-phase liquid chromatographic (RP-LC) method was developed for the quantitative determination of rizatriptan benzoate, used to treat relieves migraine headache symptoms. The developed method can be also employed for the related substance determination in bulk samples. Forced degradation studies were performed on bulk sample of rizatriptan benzoate using acid (0.5 N hydrochloric acid), base (0.1 N sodium hydroxide), oxidation (3.0% hydrogen peroxide), water hydrolysis, heat (60 degrees C) and photolytic degradation. Mild degradation of the drug substance was observed in base hydrolysis and considerable degradation observed during oxidative stress. The chromatographic method was fine tuned using the samples generated from forced degradation studies. Good resolution between the peaks corresponds to degradation products and the analyte was achieved on Agilent Zorbax SB-CN (250 mm x 4.6 mm, 5 microm) column. The mobile phase consists of a mixture of aqueous potassium di hydrogen ortho phosphate (pH 3.4), acetonitrile and methanol. The stress sample solutions were assayed against the qualified reference standard of rizatriptan benzoate and the mass balance in each case was close to 99.7% indicating that the developed method is stability indicating. Validation of the developed method was carried out as per ICH requirements.
We have evaluated the long-term outcome of excision, aspiration and no treatment of dorsal wrist ... more We have evaluated the long-term outcome of excision, aspiration and no treatment of dorsal wrist ganglia prospectively in 236 (83%) of 283 patients who responded to a postal questionnaire at a mean of 70 months. The resolution of symptoms was similar between the treatment groups (p>0.3). Pain and unsightliness improved in all three treatment groups. The prevalence of weakness and stiffness altered only slightly in all three treatment groups. More patients with a recurrent, or persistent ganglion complained of pain, stiffness and unsightliness (p<0.0001). Patient satisfaction was higher after surgical excision (p<0.0001), even if the ganglion recurred. Twenty-three of 55 (58%) untreated ganglia resolved spontaneously. The recurrence rate was 58% (45/78) and 39% (40/103) following aspiration and excision, respectively. Eight out of 103 patients had complications following surgery. In this study, neither excision nor aspiration provided significant long-term benefit over no treatment.
The dynamic behavior of two types of sandwich composites made of E-Glass Vinyl-Ester (EVE) facesh... more The dynamic behavior of two types of sandwich composites made of E-Glass Vinyl-Ester (EVE) facesheets and Corecell™ A-series foam with a polyurea interlayer was studied using a shock tube apparatus. The materials, as well as the core layer arrangements, were identical, with the only difference arising in the location of the polyurea interlayer. The foam core itself was layered with monotonically increasing wave impedance of the core layers, with the lowest wave impedance facing the shock loading. For configuration 1, the polyurea interlayer was placed behind the front facesheet, in front of the foam core, while in configuration 2 it was placed behind the foam core, in front of the back facesheet. A high-speed side-view camera, along with a high-speed back-view 3-D Digital Image Correlation (DIC) system, was utilized to capture the real time deformation process as well as mechanisms of failure. Post mortem analysis was also carried out to evaluate the overall blast performance of these two configurations. The results indicated that applying polyurea behind the foam core and in front of the back facesheet will reduce the back face deflection, particle velocity, and in-plane strain, thus improving the overall blast performance and maintaining structural integrity.
The doctors are vulnerable to substance abuse/addiction due to their ready accessibility to the s... more The doctors are vulnerable to substance abuse/addiction due to their ready accessibility to the substances of abuse. There is higher percentage use of alcohol, tranquillisers and psychedelics among medical students, and dependence rates are 5% for medical students and 3% for doctors. Majority of the substance-abusing doctors are graduates, belong to medicine speciality (21%) and majority of them prescribe drugs to themselves (37%). The consultants experience more substance related complications, despite having late age of onset of alcohol and substance dependence, less number of concomitant substance abuse and less career handicap. Stress (situational, personal and professional), medical student abuse and family history of alcoholism are the major risk factors. Despite paucity of studies in Indian population, substance use is reported between 32.5% to as high as 81.2% among medical students, intems and house physicians. In spite of the treatment dilemmas, the physicians do respond favourably to treatment. These findings have implications in planning preventive and interventional strategies for this professional group.
Lipid peroxides are considered to be the initiation factor for atherosclerosis. Present study dep... more Lipid peroxides are considered to be the initiation factor for atherosclerosis. Present study depicts that L-carnitine treatment (300 mg/kg body weight/day) for 7 and 14 days caused significant reduction in the tissue lipid peroxidations. It also shows marked improvement in the antioxidant status. By this way carnitine maintain the normal function of the cells.
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Papers by Pramod Kumar