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39 results on '"Kumar, Amar"'

3. Critical role of post-annealing in Ta/Co60Fe20B20/Ta thin film heterostructures: Structural, static, and dynamic properties

Author

Kumar Gupta, Nanhe, primary, Husain, Sajid, additional, Barwal, Vineet, additional, Hait, Soumyarup, additional, Pandey, Lalit, additional, Mishra, Vireshwar, additional, Saravanan, L., additional, Kumar, Amar, additional, Sharma, Nikita, additional, Kumar, Nakul, additional, Kumar Kedia, Sanjay, additional, and Chaudhary, Sujeet, additional

Published
2022
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4. Investigation of gelatin enabled abrasive water slurry jet machining (AWSJM)

Author

Animesh Kumar Amar and Puneet Tandon

Subjects
0209 industrial biotechnology, Work (thermodynamics), Jet (fluid), Materials science, business.industry, Nozzle, Abrasive, Mechanical engineering, 02 engineering and technology, Computational fluid dynamics, Industrial and Manufacturing Engineering, Power (physics), 020303 mechanical engineering & transports, 020901 industrial engineering & automation, 0203 mechanical engineering, Machining, Slurry, business
Abstract

The paper presents the development of an analytical model and Computational Fluid Dynamics (CFD) model of abrasive water slurry jet machining (AWSJM), along with the experimental investigation of the micro-channel formation. The proposed work presents an improvised approach of AWSJM by equipping the conventional abrasive water jet (AWJ) machine with a setup for injecting polymer (Gelatin) solution into the AWJ nozzle, which leads to efficient energy transfer, improved cutting efficiency, and increased material removal rate. The CFD model is developed to simulate jet dynamic characteristics. The modeling of abrasive water jet machining (AWJM) and AWSJM process indicates that the calculated material removal rate is proportional to the power of the water jet. It is further proven from the analytical calculations that during the process of material removal, there is energy loss in both the AWJM and AWSJM. The results from the analytical model are validated through experiments performed on an AWJ machine. The micro-channels were fabricated to compare the depth of cut in the present research work. The analytical model developed to calculate the total depth of jet penetration correlates quite well with the experimental data. It is also observed that the maximum error predicted by the analytical expression and the simulation model for velocity and energy are within 10%.

Published
2021
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9. Critical Role of Post-Annealing in Ta/Co 60Fe 20B 20/Ta Heterostructures: Structural, Static, and Dynamic Properties

Author

Chaudhary, Sujeet, primary, Gupta, Nanhe Kumar, additional, Husain, Sajid, additional, Barwal, Vineet, additional, Hait, Soumyarup, additional, Pandey, Lalit, additional, Mishra, Vireshwar, additional, Saravanan, L., additional, Kumar, Amar, additional, Sharma, Nikita, additional, Kumar, Nakul, additional, and Kedia, Sanjay Kumar, additional

Published
2022
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12. Combined effect of Benzophenone-2 and ultraviolet radiation promote photogenotoxicity and photocytotoxicity in human keratinocytes

Author

Deepti Chopra, Shruti Goyal, Saroj Kumar Amar, Ajeet K. Srivastav, and Ratan Singh Ray

Subjects
Keratinocytes, 0301 basic medicine, Cell Survival, Ultraviolet Rays, DNA damage, Population, UV filter, 010501 environmental sciences, Toxicology, medicine.disease_cause, 01 natural sciences, Cell Line, Benzophenones, 03 medical and health sciences, chemistry.chemical_compound, medicine, Humans, education, 0105 earth and related environmental sciences, education.field_of_study, Cell Cycle, Acridine orange, General Medicine, Comet assay, HaCaT, 030104 developmental biology, chemistry, Biophysics, Comet Assay, Reactive Oxygen Species, Ethidium bromide, Genotoxicity, DNA Damage
Abstract

Benzophenone-2 (BP2), a common ingredient of sunscreens formulation is widely used as UV filter. We have assessed the photogenotoxic and photocytotoxic potential of BP2. Photostability test showed that BP2 is unstable under UV exposure. Cell proliferation assay revealed that viability of HaCaT cells significantly reduced under UVA, UVB and sunlight exposure. DCF fluorescence intensity proved intracellular ROS generation capacity of BP2 under sunlight, UVA and UVB irradiation. Photodynamic degradation of guanine base of DNA is promoted by BP2 under UV treatment. Genotoxicity assessed by comet assay, showed that photosensitized BP2 enhanced DNA damage, which is measured in term of % tail DNA and olive tail moment. Genotoxic potential of BP2 was further validated with photomicronuclei assay. Photogenotoxicity of BP2 was lastly confirmed by formation of CPDs (Cyclo butane pyrimidine dimmers). DNA damage induced by BP2 was irreversible and extended incubation periods (6–12 h) not favored the recovery from damaged DNA. JC 1 staining showed significant reduction in mitochondrial membrane potential. Membrane integrity compromisation of HaCaT cells was established by AO (Acridine orange), EtBr (Ethidium bromide) staining and confirmed with sub G1 population of cell cycle. Thus, results suggest that BP2 should be avoided in topical application for safe sunscreen practices.

Published
2018
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15. Corrigendum to 'Role of type I and type II radicals in DNA damage and activation of Caspase 3 via mitochondrial pathway induced by photosensitized benzophenone' [Toxicol. Lett. 235 (2015) 84–95]

Author

Ashish Dwivedi, Saroj Kumar Amar, Deepti Chopra, Ankit Verma, Syed Faiz Mujtaba, Hari Narayan Kushwaha, Rajnish Kumar Chaturvedi, Ratan Singh Ray, and Shruti Goyal

Subjects
chemistry.chemical_compound, Chemistry, DNA damage, Radical, Mitochondrial pathway, Benzophenone, Caspase 3, General Medicine, Toxicology, Molecular biology
Published
2019
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17. Corrigendum to 'ROS mediated crosstalk between endoplasmic reticulum and mitochondria by Phloxine B under environmental UV irradiation' Journal of Photochemistry & Photobiology, B: Biology 161 (2016) 284–294

Author

Shruti Goyal, Ratan Singh Ray, Nidhi Arjaria, Manish Kumar Pal, Saroj Kumar Amar, Deepti Chopra, and Ajeet K. Srivastav

Subjects
Crosstalk (biology), Radiation, Radiological and Ultrasound Technology, Photobiology, Endoplasmic reticulum, Biophysics, Radiology, Nuclear Medicine and imaging, Mitochondrion, Biology, Cell biology
Published
2019
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18. Corrigendum to “PLGA nanoformulation of sparfloxacin enhanced antibacterial activity with photoprotective potential under ambient UV-R exposure” [Int. J. Pharm. 541 (2018) 173–187]

Author

Singh, Jyoti, primary, Dwivedi, Ashish, additional, Ray, Lipika, additional, Chopra, Deepti, additional, Dubey, Divya, additional, Srivastva, Ajeet K., additional, Kumari, Smita, additional, Kumar Yadav, Randhir, additional, Kumar Amar, Saroj, additional, Haldar, Chandana, additional, and Singh Ray, Ratan, additional

Published
2019
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19. Role of type I & type II reactions in DNA damage and activation of Caspase 3 via mitochondrial pathway induced by photosensitized benzophenone

Author

Ankit Verma, Hari Narayan Kushwaha, Syed Faiz Mujtaba, Deepti Chopra, Saroj Kumar Amar, Rajnish Kumar Chaturvedi, Shruti Goyal, Ratan Singh Ray, and Ashish Dwivedi

Subjects
Keratinocytes, Cell Survival, Ultraviolet Rays, DNA damage, Population, Apoptosis, Caspase 3, Toxicology, Risk Assessment, Cell Line, Benzophenones, Superoxides, Humans, DNA Breaks, Single-Stranded, education, Caspase, bcl-2-Associated X Protein, Membrane Potential, Mitochondrial, chemistry.chemical_classification, Reactive oxygen species, education.field_of_study, Photolysis, Dose-Response Relationship, Drug, L-Lactate Dehydrogenase, biology, Hydroxyl Radical, Chemistry, Cytochrome c, Cytochromes c, General Medicine, Mitochondria, Enzyme Activation, Oxidative Stress, HaCaT, Proto-Oncogene Proteins c-bcl-2, Biochemistry, biology.protein, Lipid Peroxidation, Phototoxicity, Sunscreening Agents, Signal Transduction
Abstract

Sunscreen users have been increased, since excessive sun exposure increased the risk of skin diseases. Benzophenone (BP) and its derivatives are commonly used in sunscreens as UV blocker. Its photosafety is concern for human health. Our study showed the role of type-I and type-II radicals in activation of caspase 3 and phototoxicity of BP under sunlight/UV radiation. BP photodegraded and formed two photoproducts. BP generates reactive oxygen species (ROS) singlet oxygen ((1)O2), superoxide anion (O2˙(-)) and hydroxyl radical (˙OH) through type-I and type-II photodynamic mechanisms. Photocytotoxicity significantly reduced cell viability under sunlight, UVB and UVA. DCF fluorescence confirmed intracellular ROS generation. BP showed single strand DNA breakage, further proved by cyclobutane pyrimidine dimmers (CPDs) formation. Lipid peroxidation and LDH leakage were enhanced by BP. P21 dependent cell cycle study showed sub G1 population which advocates apoptotic cell death, confirmed through AO/EB and annexin V/PI staining. BP decreased mitochondrial membrane potential, death protein released and activated caspase. We proposed cytochrome c regulated caspase 3 dependent apoptosis in HaCaT cell line through down regulation of Bcl2/Bax ratio. Phototoxicity potential of its photoproducts is essential to understand its total environmental fate. Hence, we conclude that BP may replace from cosmetics preparation of topical application.

Published
2015
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20. Corrigendum to 'Involvement of cathepsin B in mitochondrial apoptosis by p-phenylenediamine under ambient UV radiation' [J. Hazard. Mater. 300 (2015) 415–425]

Author

Ankit Verma, Jyoti Singh, Ratan Singh Ray, Divya Dubey, Shruti Goyal, Saroj Kumar Amar, Hari Narayan Kushwaha, and Manish Kumar Pal

Subjects
chemistry.chemical_compound, Environmental Engineering, chemistry, Apoptosis, Health, Toxicology and Mutagenesis, Environmental Chemistry, p-Phenylenediamine, Pollution, Waste Management and Disposal, Molecular biology, Cathepsin B
Published
2019
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21. Corrigendum to 'PLGA nanoformulation of sparfloxacin enhanced antibacterial activity with photoprotective potential under ambient UV-R exposure' [Int. J. Pharm. 541 (2018) 173–187]

Author

Lipika Ray, Chandana Haldar, Divya Dubey, Saroj Kumar Amar, Randhir Kumar Yadav, Smita Kumari, Jyoti Singh, Deepti Chopra, Ratan Singh Ray, Ajeet K Srivastva, and Ashish Dwivedi

Subjects
PLGA, chemistry.chemical_compound, Sparfloxacin, chemistry, INT, medicine, Pharmaceutical Science, Pharmacology, Antibacterial activity, medicine.drug
Published
2019
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24. Corrigendum to 'Photosensitized rose bengal induced phototoxicity on human melanoma cell line under natural sunlight exposure' [J. Photochem. Photobiol. B Biol. 156(March 2016) 87–99]

Author

Saroj Kumar Amar, Hari Narayan Kushwaha, Ajeet K. Srivastav, Rajnish Kumar Chaturvedi, Ankit Verma, Syed Faiz Mujtaba, Ashish Dwivedi, Ratan Singh Ray, and Shruti Goyal

Subjects
Sunlight, chemistry.chemical_compound, Radiation, Radiological and Ultrasound Technology, chemistry, Cell culture, Biophysics, Rose bengal, Radiology, Nuclear Medicine and imaging, Human melanoma, Phototoxicity, Molecular biology
Published
2018
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