abha shukla | National Physical Laboratory, New Delhi, India (original) (raw)
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Books by abha shukla
"Hydrocarbon contamination in the environment is a very serious problem whether it comes from pet... more "Hydrocarbon contamination in the environment is a very serious problem whether it comes from petroleum, pesticides or other toxic organic matter. Environmental pollution caused by petroleum is of great concern because petroleum hydrocarbons are toxic to all forms of life. Environmental contamination by crude oil is relatively common because of its widespread use and its associated disposal operations and accidental spills........
Heavy metals are naturally present in soils; however due to human activity, the concentration of heavy metals in soil is increasing. Some areas contain such a high concentrations of heavy metals and metalloids that they are affecting the natural ecosystem. It has been observed that hydrocarbon contaminated sites co-contaminated with heavy........."
Papers by abha shukla
International Journal of Hydrogen Energy
Abstract Hydrogen gas is a zero-emission fuel for clean environment. In present work a novel envi... more Abstract Hydrogen gas is a zero-emission fuel for clean environment. In present work a novel environment friendly hydrogen producing technique based on nascently invented Hydroelectric cell has been reported. Hydroelectric cell is one of the unique non-polluting H2 gas generation methods compared to photo-biosynthesis, photo-electro-catalysis and thermo-chemical etc. Spontaneous dissociation of water molecule by Hydroelectric cell (HEC) has led this study for effective production of hydrogen gas. Moreover, a nanoporous lithium substituted magnesium ferrite used in HEC dissociates water molecule to produce hydrogen without using any electrolyte and light. Ferrite pellet combined with zinc and silver electrodes known as hydroelectric cell produces zinc hydroxide and hydrogen gas as a result of redox reaction. Nanoporous and oxygen deficient ferrite pellet has been synthesised with optimized processing conditions. Maximum average nanopore size distribution has been obtained 3.8 nm by N2 adsorption-desorption isotherm. Surface dangling bonds of unsaturated cations and oxygen vacancies in ferrite chemidissociate water molecule into hydroxide and hydronium ion. High purity hydrogen gas is produced continuously by applying different external voltage only on hydroelectric cell. Collected gas has been analysed by gas chromatography in comparison to pure reference hydrogen gas. This technique has produced hydrogen in large quantity 1.856 mmol/h compared to existing photocatalytic active ferrite methods. Hydrogen gas generation by HEC is an exclusively facile, low cost and novel technique.
Journal of Biotechnology & Biomaterials, 2016
Short Communication OMICS International J o ur nal of B io te ch nology & B io materia ls
Journal of Petroleum & Environmental Biotechnology, 2015
Antonie van Leeuwenhoek, 2014
Never before electricity has been generated out of metal oxides without using any light (UV/IR), ... more Never before electricity has been generated out of metal oxides without using any light (UV/IR), acid or alkali but it has been achieved by adding few drops of water on nano porous metal oxide based Hydroelectric cell (HEC) at room temperature. Electricity generation has been validated and unified for six different metal oxides based on the principle of water dissociation at oxygen deficient nonporous pellet. Presence of oxygen vacancies at the surface of all metal oxide samples has been confirmed by Raman and Photoluminescence spectroscopy. Oxide based HEC delivers maximum power ~16.6 mW in 4.48 cm2 area of SnO2 cell with peak current 22.2 mA, approximately 2.075 times higher than reported 8 mA current in ferrite based HEC. Water chemidissociation at metal oxide surface was found to be reinforced predominantly by electronegativity of metal cations and defect structures at nanoporous surface. Divergent peak current values ranging from 22.2 mA to 1.1 mA were obtained depending on int...
Antonie van Leeuwenhoek
The ability of the human fungal pathogen Candida albicans to reversibly switch between different ... more The ability of the human fungal pathogen Candida albicans to reversibly switch between different morphological forms and establish biofilms is crucial for establishing infection. Targeting phenotypic plasticity and biofilm formation in C. albicans represents a new concept for antifungal drug discovery. The present study evaluated the influence of cyclic lipopeptide biosurfactant produced by Bacillus amyloliquefaciens strain AR2 on C. albicans biofilms. The biosurfactant was characterized as a mixture of iturin and fengycin by MALDI-TOF and amino acid analysis. The biosurfactant exhibited concentration dependent growth inhibition and fungicidal activity. The biosurfactant at sub-minimum growth inhibition concentration decreased cell surface hydrophobicity, hindered germ tube formation and reduced the mRNA expression of hyphae-specific gene HWP1 and ALS3 without exhibiting significant growth inhibition. The biosurfactants inhibited biofilm formation in the range of 46–100 % depending upon the concentration and Candida strains. The biosurfactant treatment dislodged 25–100 % of preformed biofilm from polystyrene plates. The biosurfactant retained its antifungal and antibiofilm activity even after exposure to extreme temperature. By virtue of the ability to inhibit germ tube and biofilm formation, two important traits of C. albicans involved in establishing infection, lipopeptides from strain AR2 may represent a potential candidate for developing heat stable anti-Candida drugs.
"Hydrocarbon contamination in the environment is a very serious problem whether it comes from pet... more "Hydrocarbon contamination in the environment is a very serious problem whether it comes from petroleum, pesticides or other toxic organic matter. Environmental pollution caused by petroleum is of great concern because petroleum hydrocarbons are toxic to all forms of life. Environmental contamination by crude oil is relatively common because of its widespread use and its associated disposal operations and accidental spills........
Heavy metals are naturally present in soils; however due to human activity, the concentration of heavy metals in soil is increasing. Some areas contain such a high concentrations of heavy metals and metalloids that they are affecting the natural ecosystem. It has been observed that hydrocarbon contaminated sites co-contaminated with heavy........."
International Journal of Hydrogen Energy
Abstract Hydrogen gas is a zero-emission fuel for clean environment. In present work a novel envi... more Abstract Hydrogen gas is a zero-emission fuel for clean environment. In present work a novel environment friendly hydrogen producing technique based on nascently invented Hydroelectric cell has been reported. Hydroelectric cell is one of the unique non-polluting H2 gas generation methods compared to photo-biosynthesis, photo-electro-catalysis and thermo-chemical etc. Spontaneous dissociation of water molecule by Hydroelectric cell (HEC) has led this study for effective production of hydrogen gas. Moreover, a nanoporous lithium substituted magnesium ferrite used in HEC dissociates water molecule to produce hydrogen without using any electrolyte and light. Ferrite pellet combined with zinc and silver electrodes known as hydroelectric cell produces zinc hydroxide and hydrogen gas as a result of redox reaction. Nanoporous and oxygen deficient ferrite pellet has been synthesised with optimized processing conditions. Maximum average nanopore size distribution has been obtained 3.8 nm by N2 adsorption-desorption isotherm. Surface dangling bonds of unsaturated cations and oxygen vacancies in ferrite chemidissociate water molecule into hydroxide and hydronium ion. High purity hydrogen gas is produced continuously by applying different external voltage only on hydroelectric cell. Collected gas has been analysed by gas chromatography in comparison to pure reference hydrogen gas. This technique has produced hydrogen in large quantity 1.856 mmol/h compared to existing photocatalytic active ferrite methods. Hydrogen gas generation by HEC is an exclusively facile, low cost and novel technique.
Journal of Biotechnology & Biomaterials, 2016
Short Communication OMICS International J o ur nal of B io te ch nology & B io materia ls
Journal of Petroleum & Environmental Biotechnology, 2015
Antonie van Leeuwenhoek, 2014
Never before electricity has been generated out of metal oxides without using any light (UV/IR), ... more Never before electricity has been generated out of metal oxides without using any light (UV/IR), acid or alkali but it has been achieved by adding few drops of water on nano porous metal oxide based Hydroelectric cell (HEC) at room temperature. Electricity generation has been validated and unified for six different metal oxides based on the principle of water dissociation at oxygen deficient nonporous pellet. Presence of oxygen vacancies at the surface of all metal oxide samples has been confirmed by Raman and Photoluminescence spectroscopy. Oxide based HEC delivers maximum power ~16.6 mW in 4.48 cm2 area of SnO2 cell with peak current 22.2 mA, approximately 2.075 times higher than reported 8 mA current in ferrite based HEC. Water chemidissociation at metal oxide surface was found to be reinforced predominantly by electronegativity of metal cations and defect structures at nanoporous surface. Divergent peak current values ranging from 22.2 mA to 1.1 mA were obtained depending on int...
Antonie van Leeuwenhoek
The ability of the human fungal pathogen Candida albicans to reversibly switch between different ... more The ability of the human fungal pathogen Candida albicans to reversibly switch between different morphological forms and establish biofilms is crucial for establishing infection. Targeting phenotypic plasticity and biofilm formation in C. albicans represents a new concept for antifungal drug discovery. The present study evaluated the influence of cyclic lipopeptide biosurfactant produced by Bacillus amyloliquefaciens strain AR2 on C. albicans biofilms. The biosurfactant was characterized as a mixture of iturin and fengycin by MALDI-TOF and amino acid analysis. The biosurfactant exhibited concentration dependent growth inhibition and fungicidal activity. The biosurfactant at sub-minimum growth inhibition concentration decreased cell surface hydrophobicity, hindered germ tube formation and reduced the mRNA expression of hyphae-specific gene HWP1 and ALS3 without exhibiting significant growth inhibition. The biosurfactants inhibited biofilm formation in the range of 46–100 % depending upon the concentration and Candida strains. The biosurfactant treatment dislodged 25–100 % of preformed biofilm from polystyrene plates. The biosurfactant retained its antifungal and antibiofilm activity even after exposure to extreme temperature. By virtue of the ability to inhibit germ tube and biofilm formation, two important traits of C. albicans involved in establishing infection, lipopeptides from strain AR2 may represent a potential candidate for developing heat stable anti-Candida drugs.