49 results on '"Shyamal Roy"'
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2. Ionic Liquid–Based Pretreatment of Lignocellulosic Biomass for Bioconversion: a Critical Review
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Shyamal Roy and Shishir P. S. Chundawat
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Renewable Energy, Sustainability and the Environment ,Agronomy and Crop Science ,Energy (miscellaneous) - Published
- 2022
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3. Transformation of Wurtzite ZnO to a New Triclinic Nanoporous ZnO Phase via Hydrothermal Treatment with Metformin for Designing Proton Conducting Material
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Aswini Ghosh, Sauvik Chatterjee, Asim Bhaumik, Shyamal Roy, Sayantan Chongdar, and A. Palui
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010405 organic chemistry ,business.industry ,Chemistry ,Nanoporous ,Band gap ,Organic Chemistry ,Nanoparticle ,General Chemistry ,Triclinic crystal system ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Semiconductor ,Chemical engineering ,Phase (matter) ,business ,Nanoscopic scale ,Wurtzite crystal structure - Abstract
Zinc oxide is one of the most widely studied semiconductor metal oxides, which predominantly crystallizes as hexagonal wurtzite and often cubic zinc-blende phases. Here we report the transformation of the highly stable wurtzite ZnO to a new triclinic phase NZO-2 by using metformin as a template during post-synthesis hydrothermal treatment. This crystalline phase of the material NZO-2 has been identified through the refinement of the powder XRD data. NZO-2 possesses porous rod like particle morphology consisting of the self-assembly of 3-7 nm size spherical nanoparticles and interparticle nanoscopic voids spaces. NZO-2 has been surface phosphorylated and the resulting material displayed good proton conductivity. Further, NZO-2 displayed ultra-low band gap of 1.74 eV, thereby responsible for red emission under high energy laser excitation and this may open new opportunities in optoelectronic application of ZnO.
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- 2021
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4. La-doped LiMnPO4/C cathode material for Lithium-ion battery
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Sourav Nag and Shyamal Roy
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Applied Mathematics ,General Chemical Engineering ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
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5. STUDY OF VITAMIN D STATUS IN TYPE II DIABETES MELLITUS PATIENTS AND ITS CORRELATION TO THYROID FUNCTION: A CROSS SECTIONAL STUDY IN A TERTIARY HEALTH CARE CENTRE IN TRIPURA
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Papiya Deb, Atul Debbarma, and Shyamal Roy
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medicine.medical_specialty ,endocrine system diseases ,Health care centre ,Cross-sectional study ,business.industry ,030209 endocrinology & metabolism ,Correlation ,Type ii diabetes ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Vitamin D and neurology ,Medicine ,030212 general & internal medicine ,Thyroid function ,business - Abstract
Background: There has been a marked variance in the prevalence of Vitamin D deciency in India. Limited evidence is available regarding the correlation of Vitamin D with thyroid hormones in patients with Type II Diabetes mellitus (T2DM). Aims AND Objectives: To study the correlation of Vitamin D with thyroid hormones in patients with Type II Diabetes mellitus at tertiary health care in Tripura. Materials And Methods: Hundred patients with T2DM diagnosed as per American Diabetes Association (ADA) were studied in acrosssectional study which was conducted in the Department of Medicine at AGMC&GBP Hospital from January 2019 – June 2020. Blood tests were performed to estimate serum vitamin D level and thyroid prole and correlation was obtained with glycemic parameters. Results: T2DM was more prevalent in the age group of 60-70 years with mean age being 55.28 years. Majority had (52%) hypothyroidism, 38% had had vitamin D deciency and 13% had vitamin D insufciency. Majority of the Vitamin D decient patients TSH > 5 µIU/mL (31%). Linear regression analysis showed that inverse relationship between TSH and Vitamin D, HbA1c and Vitamin D. An equation of Vitamin D level estimation was derived as Vitamin D level = 28.48 – 0.81 * HbA1c level. Conclusion: Prevalence of vitamin d deciency is more prevalent among hypothyroid diabetics and the severity of the Vitamin D deciency correlated with hypothyroid status.
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- 2021
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6. The Role of JMJD3 in Ovarian Follicular Development
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Shyamal Roy
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Histones ,Mice ,Jumonji Domain-Containing Histone Demethylases ,Fertility ,Endocrinology ,Follicular Atresia ,Ovary ,Commentary ,Animals ,Humans ,Female ,Research Article - Abstract
In females, reproductive success is dependent on the expression of a number of genes regulated at different levels, one of which is through epigenetic modulation. How a specific epigenetic modification regulates gene expression and their downstream effect on ovarian function are important for understanding the female reproductive process. The trimethylation of histone3 at lysine27 (H3K27me3) is associated with gene repression. JMJD3 (or KDM6b), a jumonji domain-containing histone demethylase specifically catalyzes the demethylation of H3K27me3, that positively influences gene expression. This study reports that the expression of JMJD3 specifically in the ovarian granulosa cells (GCs) is critical for maintaining normal female fertility. Conditional deletion of Jmjd3 in the GCs results in a decreased number of total healthy follicles, disrupted estrous cycle, and increased follicular atresia culminating in subfertility and premature ovarian failure. At the molecular level, the depletion of Jmjd3 and RNA-seq analysis reveal that JMJD3 is essential for mitochondrial function. JMJD3-mediated reduction of H3K27me3 induces the expression of Lif (Leukemia inhibitory factor) and Ctnnb1 (β-catenin), that in turn regulate the expression of key mitochondrial genes critical for the electron transport chain. Moreover, mitochondrial DNA content is also significantly decreased in Jmjd3 null GCs. Additionally, we have uncovered that the expression of Jmjd3 in GCs decreases with age, both in mice and in humans. Thus, in summary, our studies highlight the critical role of JMJD3 in nuclear-mitochondrial genome coordination that is essential for maintaining normal ovarian function and female fertility and underscore a potential role of JMJD3 in female reproductive aging.
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- 2022
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7. Parametric Optimization and Kinetics Study of Effective Removal of Methylene Blue by Citric Acid-Modified Arjun Bark Powder
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Shyamal Roy and Dilip Kumar Mondal
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Renewable Energy, Sustainability and the Environment - Published
- 2022
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8. Investigating Nanoscale Contact Using AFM-Based Indentation and Molecular Dynamics Simulations
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Shyamal Roy, Sönke Wille, Dan Mordehai, and Cynthia A. Volkert
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Condensed Matter::Materials Science ,thermally activated processes ,contact mechanics ,nanoindentation ,atomic force microscopy ,molecular dynamics simulations ,Metals and Alloys ,ddc:530 ,General Materials Science - Abstract
In this work we study nanocontact plasticity in Au thin films using an atomic force microscope based indentation method with the goal of relating the changes in surface morphology to the dislocations created by deformation. This provides a rigorous test of our understanding of deformation and dislocation mechanisms in small volumes. A series of indentation experiments with increasing maximum load was performed. Distinct elastic and plastic regimes were identified in the force-displacement curves, and the corresponding residual imprints were measured. Transmission electron microscope based measured dislocation densities appear to be smaller than the densities expected from the measured residual indents. With the help of molecular dynamics simulations we show that dislocation nucleation and glide alone fail to explain the low dislocation density. Increasing the temperature of the simulations accelerates the rate of thermally activated processes and promotes motion and annihilation of dislocations under the indent while transferring material to the upper surface; dislocation density decreases in the plastic zone and material piles up around the indent. Finally, we discuss why a significant number of cross-slip events is expected beneath the indent under experimental conditions and the implications of this for work hardening during wear.
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- 2022
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9. Enhancement of Li+ Ion Kinetics in Boehmite Nanofiber Coated Polypropylene Separator in Lifepo4 Cells
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Shyamal Roy, Sourav Nag, and Sourindra Mahanty
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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10. Enhanced Degradation of Phenol by Catalytic Wet Oxidation Over Novel Ceria Promoted Mesoporous Silica Supported Ru-Fe3o4 Catalyst: A Combined Experimental and Dft Study
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Shyamal Roy and Dilip Kumar Mondal
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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11. Prediabetes, dyslipidemia and c-reactive protein levels among stroke patients: a hospital-based study in north-east India
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Moumana Das, Subhadip Paul, and Shyamal Roy
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General Engineering - Abstract
Background: Stroke is defined as an abrupt onset of a neurologic deficit lasting for more than 24 hours that is attributable to a focal vascular cause. Hyperglycemia and dyslipidemia are often documented in stroke patients. Elevated CRP level is independently associated with the excessive risk of ischemic stroke. Aim and Objectives were to evaluate the glycemic status, lipid profile and c-reactive protein level in stroke patients admitted in a teaching institute of north-east India.Methods: A cross-sectional hospital-based study conducted in the department of medicine, Agartala Government Medical College and GBP hospital, within a period of January 2020 to June 2021. Data were analyzed by SPSS software version 15 using appropriate statistical tests.Results: Among 200 patients of stroke, 50% was found to be pre-diabetic, 40% known diabetic and 10% newly diagnosed diabetic. 60% were hypertensives. Among them, 80% had ischaemic stroke and 20% hemorrhagic stroke. 70% of the patients had hypercholesterolemia, 60% had hypertriglyceridemia. 80% had raised serum LDL and 57% decreased serum HDL. Out of 200 patients, 60% was found to have raised serum CRP level. 55% of ischaemic stroke patients and 5% of hemorrhagic stroke patients had raised CRP level.Conclusions: Prediabetes and newly diagnosed diabetes are highly prevalent in patients with stroke or TIA. As the prevalence of prediabetes is growing rapidly, prediabetes might become one of the most important modifiable therapeutic targets in both primary and secondary prevention. Early detection of dyslipidemia and treatment with drugs along with dietary modifications and lifestyle changes can reduce the risk of stroke. Since, it was a cross-sectional study, these results need to be validated by further long-term prospective studies.
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- 2022
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12. Developmental Expression of Bone Morphogenetic Protein 2 (BMP2)-Induced Genes in Fetal Mouse Ovaries [A335]
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Rebecca L. Anderson, Prabuddha Chakraborty, and Shyamal Roy
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Obstetrics and Gynecology - Published
- 2022
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13. Economics of Different Pretreatment Technologies
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Shyamal Roy
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- 2021
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14. Conclusions and Recommendations
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Shyamal Roy
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- 2021
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15. Physical Pretreatments
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Shyamal Roy
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- 2021
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16. Introduction
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Shyamal Roy
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- 2021
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17. Pre-Treatment Methods of Lignocellulosic Biomass for Biofuel Production
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Shyamal Roy
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- 2021
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18. Chemical Pretreatments
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Shyamal Roy
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- 2021
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19. Combined Pretreatment
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Shyamal Roy
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- 2021
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20. Biological Pretreatment
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Shyamal Roy
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- 2021
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21. Problems of the Industrial Adaptation
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Shyamal Roy
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Risk analysis (engineering) ,Computer science ,Adaptation (computer science) - Published
- 2021
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22. Physicochemical Pretreatments
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Shyamal Roy
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- 2021
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23. Ammonia-salt solvent promotes cellulosic biomass deconstruction under ambient pretreatment conditions to enable rapid soluble sugar production at ultra-low enzyme loadings
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Ramendra K. Pal, Shih-Hsien Liu, Shyamal Roy, Hugh O'Neill, Loukas Petridis, Chao Zhao, Zhi Yang, Leonardo da Costa Sousa, Shishir P. S. Chundawat, Sai Venkatesh Pingali, and Shashwat Gupta
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Solvent ,chemistry.chemical_compound ,Hydrolysis ,chemistry ,Chemical engineering ,Cellulosic ethanol ,Environmental Chemistry ,Lignin ,Lignocellulosic biomass ,Fiber ,Cellulose ,Pollution ,Dissolution - Abstract
Here, we report a novel ammonia : ammonium salt solvent based pretreatment process that can rapidly dissolve crystalline cellulose into solution and eventually produce highly amorphous cellulose under near-ambient conditions. Pre-activating the cellulose I allomorph to its ammonia–cellulose swollen complex (or cellulose III allomorph) at ambient temperatures facilitated rapid dissolution of the pre-activated cellulose in the ammonia-salt solvent (i.e., ammonium thiocyanate salt dissolved in liquid ammonia) at ambient pressures. For the first time in reported literature, we used time-resolved in situ neutron scattering methods to characterize the cellulose polymorphs structural modification and understand the mechanism of crystalline cellulose dissolution into a ‘molecular’ solution in real-time using ammonia-salt solvents. We also used molecular dynamics simulations to provide insight into solvent interactions that non-covalently disrupted the cellulose hydrogen-bonding network and understand how such solvents are able to rapidly and fully dissolve pre-activated cellulose III. Importantly, the regenerated amorphous cellulose recovered after pretreatment was shown to require nearly ∼50-fold lesser cellulolytic enzyme usage compared to native crystalline cellulose I allomorph for achieving near-complete hydrolytic conversion into soluble sugars. Lastly, we provide proof-of-concept results to further showcase how such ammonia-salt solvents can pretreat and fractionate lignocellulosic biomass like corn stover under ambient processing conditions, while selectively co-extracting ∼80–85% of total lignin, to produce a highly digestible polysaccharide-enriched feedstock for biorefinery applications. Unlike conventional ammonia-based pretreatment processes (e.g., Ammonia Fiber Expansion or Extractive Ammonia pretreatments), the proposed ammonia-salt process can operate at near-ambient conditions to greatly reduce the pressure/temperature severity necessary for conducting effective ammonia-based pretreatments on lignocellulose.
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- 2020
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24. Selective CO2 reduction to methane catalyzed by mesoporous Ru-Fe3O4/CeOx-SiO2 in a fixed bed flow reactor
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Shyamal Roy, Dilip Kumar Mondal, Sauvik Chatterjee, Avik Chowdhury, Tuhin Suvra Khan, M. Ali Haider, Subhash Mandal, Debraj Chandra, Michikazu Hara, and Asim Bhaumik
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Process Chemistry and Technology ,Physical and Theoretical Chemistry ,Catalysis - Published
- 2022
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25. Enhancement of Li+ ion kinetics in boehmite nanofiber coated polypropylene separator in LiFePO4 cells
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Sourav Nag, Atin Pramanik, Shyamal Roy, and Sourindra Mahanty
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Inorganic Chemistry ,History ,Polymers and Plastics ,Materials Chemistry ,Ceramics and Composites ,Business and International Management ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Industrial and Manufacturing Engineering ,Electronic, Optical and Magnetic Materials - Published
- 2022
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26. KNOWLEDGE OF TYPE 2 DIABETES MELLITUS AND ITS RISK FACTORS AMONG ADULT POPULATION IN RURAL AREAS OF WEST DISTRICT OF TRIPURA- A CROSS SECTIONAL STUDY
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Shyamal Roy, S. Kr. Debbarma, and Taranga Reang
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Blood pressure ,business.industry ,Cross-sectional study ,Environmental health ,Diabetes mellitus ,Medicine ,Type 2 Diabetes Mellitus ,Blood sugar ,Type 2 diabetes ,Rural area ,business ,medicine.disease ,Risk assessment - Published
- 2019
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27. ADHERENCE TO TREATMENT AMONG TYPE 2 DIABETES PATIENTS ATTENDING TERTIARY CARE HOSPITAL IN AGARTALA CITY- A CROSS-SECTIONAL STUDY
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Taranga Reang and Shyamal Roy
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03 medical and health sciences ,medicine.medical_specialty ,0302 clinical medicine ,Cross-sectional study ,business.industry ,Family medicine ,medicine ,030209 endocrinology & metabolism ,030212 general & internal medicine ,Type 2 diabetes ,Tertiary care hospital ,medicine.disease ,business - Published
- 2018
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28. KNOWLEDGE OF DIABETES AMONG TYPE 2 DIABETES PATIENTS AND THEIR BLOOD GLUCOSE LEVEL- A CROSS-SECTIONAL STUDY
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Shyamal Roy and Taranga Reang
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03 medical and health sciences ,medicine.medical_specialty ,0302 clinical medicine ,business.industry ,Cross-sectional study ,Internal medicine ,Diabetes mellitus ,Medicine ,030209 endocrinology & metabolism ,030212 general & internal medicine ,Type 2 diabetes ,business ,medicine.disease - Published
- 2018
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29. TOBACCO USE AND BODY MASS INDEX AMONG ADULT POPULATION IN SELECTED URBAN AREA OF AGARTALA CITY- A CROSS-SECTIONAL STUDY
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Aman Kumar, Shyamal Roy, and Taranga Reang
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geography ,Tobacco use ,geography.geographical_feature_category ,business.industry ,Cross-sectional study ,Adult population ,030204 cardiovascular system & hematology ,Urban area ,03 medical and health sciences ,0302 clinical medicine ,Environmental health ,Medicine ,030212 general & internal medicine ,business ,Body mass index - Published
- 2018
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30. DIETARY HABIT AND NUTRITIONAL STATUS OF INDIGENOUS TRIBAL POPULATION OF WEST DISTRICT OF TRIPURA- A CROSS-SECTIONAL STUDY
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Shyamal Roy, Taranga Reang, and Aman Kumar
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0106 biological sciences ,education.field_of_study ,business.industry ,Cross-sectional study ,Population ,Nutritional status ,04 agricultural and veterinary sciences ,040401 food science ,01 natural sciences ,Indigenous ,0404 agricultural biotechnology ,Environmental health ,Medicine ,Dietary habit ,business ,education ,010606 plant biology & botany - Published
- 2017
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31. Kinetic Study of Biogas Recovery from Thermo-chemically Pre-treated Rice Husk
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Chanchal Mondal, Aritra Das, and Shyamal Roy
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Waste management ,Chemistry ,020209 energy ,General Chemical Engineering ,Kinetics ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Husk ,Anaerobic digestion ,Biogas ,0202 electrical engineering, electronic engineering, information engineering ,0105 earth and related environmental sciences ,Biogas production - Abstract
Six simple kinetic models were used to perform comparative investigations of the kinetics of biogas production from thermo-chemically pre-treated rice husk which were heated at 155°C for 4 h prior ...
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- 2017
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32. Annihilation of edge dislocation loops via climb during nanoindentation
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Dan Mordehai and Shyamal Roy
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010302 applied physics ,Work (thermodynamics) ,Materials science ,Polymers and Plastics ,Condensed matter physics ,Metals and Alloys ,02 engineering and technology ,Nanoindentation ,Physics::Classical Physics ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Crystallography ,Creep ,Free surface ,0103 physical sciences ,Ceramics and Composites ,Climb ,Diffusion (business) ,Dislocation ,0210 nano-technology - Abstract
In this work, we explore the role of dislocation climb in annihilating the dislocation microstructure produced during a nanoindentation test. We produce creep conditions in Molecular Dynamics (MD) simulations of nanoindentation and show that half prismatic edge dislocation loops annihilate via pipe diffusion of vacancies from the free surface. Inspired by the MD simulations, we develop a model for the annihilation rate of these loops via pipe diffusion and compare it with the contribution of bulk diffusion. The model allows us discussing the temperatures at which we expect climb to prevail in experimental conditions and explain why climb is imperative during nanoindentation experiments.
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- 2017
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33. A multiscale study of the size-effect in nanoindentation of Au nanoparticles
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R. Gatti, Shyamal Roy, Dan Mordehai, Benoit Devincre, Institute of Aerodynamics and Fluid Mechanics (AER), Technische Universität München [München] (TUM), Technion - Israel Institute of Technology [Haifa], LEM, UMR 104 CNRS-ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Centre National de la Recherche Scientifique (CNRS)-Université Paris Saclay (COmUE), Laboratoire d'étude des microstructures [Châtillon] (LEM - ONERA - CNRS), Centre National de la Recherche Scientifique (CNRS)-ONERA, and Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM)
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Materials science ,General Computer Science ,MOLECULAR DYNAMICS SIMULATIONS ,General Physics and Astronomy ,Nanoparticle ,NANOPARTICULES ,02 engineering and technology ,NANOINDENTATION ,SIZE-EFFECT ,010402 general chemistry ,01 natural sciences ,Molecular dynamics ,[SPI]Engineering Sciences [physics] ,SIMULATIONS DE DYNAMIQUE MOLÉCULAIRE ,DISCRETE DISLOCATION DYNAMICS ,[CHIM]Chemical Sciences ,General Materials Science ,Composite material ,ComputingMilieux_MISCELLANEOUS ,[PHYS]Physics [physics] ,DYNAMIQUE DE DISLOCATION DISCRÈTE ,Lateral dislocation ,EFFET DE TAILLE ,General Chemistry ,Nanoindentation ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Shear (sheet metal) ,Computational Mathematics ,Mechanics of Materials ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Dislocation ,0210 nano-technology ,Discrete dislocation - Abstract
The mechanical response of nanoparticles is different than that of thin-films during nanoindentation tests. Moreover, it was shown experimentally that smaller nanoparticles are softer for nanoindentation. This size effect was attributed to the proximity of the free lateral surfaces to the indenter, which leads to dislocation-free surface interactions. We present here a multiscale study to show that the size effect is controlled by the interaction of the plastic zone formed beneath the indent and the lateral free surfaces. The detailed dislocation mechanisms and their interactions with the free surfaces are investigated using molecular dynamics (MD) and discrete dislocation dynamics (DDD) simulations. Au nanoparticles in the size range of 9–116 nm were indented with these two simulation techniques. The simulations show that shear dislocation loops are nucleated beneath the indent on all { 1 1 1 } slip planes. Dislocations interactions facilitate their escape from beneath the indent, either by forming v- and u-shaped dislocations or prismatic loops that glide towards the lower part of the nanoparticles, or through glissile interactions that promote lateral dislocation motion. The effect of size on these dislocation mechanisms is discussed.
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- 2019
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34. Catalytic wet air oxidation of aqueous solution of phenol in a fixed bed reactor over Ru catalysts supported on ceria promoted MCM-41
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Chandona Mondal, Shyamal Roy, and Dilip Kumar Mondal
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Chemistry ,Thermal desorption spectroscopy ,General Chemical Engineering ,Inorganic chemistry ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,MCM-41 ,Chemisorption ,Oxidizing agent ,engineering ,Noble metal ,Wet oxidation ,Temperature-programmed reduction ,0210 nano-technology - Abstract
Catalytic wet air oxidation (CWAO) of phenol was carried out in a fixed bed reactor over a noble metal (Ru) supported on silica MCM-41 material. The addition of small amounts of ceria as a promoter to the MCM-41 material enhanced both the activity and selectivity of Ru in this reaction, with significant conversions of about 99% obtained at 413 K and 18 bar oxygen pressure. The oxidation of phenol required moderate temperature and oxygen pressure, and the oxidizing capacity of the catalyst required adjustment. The activation energy of the oxidation reaction was found to be 33 kJ mol−1 at 413 K using the ceria promoted Ru/MCM-41 catalyst. The supports and catalysts were characterized using the Brunauer–Emmett–Teller (BET) surface area, temperature programmed reduction (TPR), CO chemisorption, temperature programmed desorption (TPD), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and inductively coupled plasma atomic emission spectroscopy (ICP-AES).
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- 2016
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35. Pretreatment Methods of Ligno - Cellulosic Biomass: A Review
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Chanchal Mondal, Aritra Das, and Shyamal Roy
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Organic solid wastes ,Chemistry ,General Engineering ,lignin ,recalcitrance. _______________ ,municipal solid waste ,pretreatment ,Pretreatment method ,Pulp and paper industry ,hydrolysis ,lcsh:TA1-2040 ,Cellulosic ethanol ,lcsh:Technology (General) ,lcsh:T1-995 ,lcsh:Engineering (General). Civil engineering (General) - Abstract
Present work primarily deals with the exhaustive investigations of rapid de-lignification processes from source-sorted organic fractions that are recalcitrant in nature. Organic solid wastes (OSW) belongs to the organic fraction of municipal solid wastes (MSW) and they act as enormous potential substrate for alternative source of energy in the form of bio-fuels. Nevertheless, these substrates are not easily biodegradable and the degree of biodegradability is solely dependent on the composition & characteristic of organic solid wastes in municipal solid wastes. The component responsible for recalcitrance of organic solid wastes is lignin that occurs in variable amounts in different plant residues. In order to remove the recalcitrance from organic fraction municipal solid wastes and to make it more easily degradable by microbial consortia, certain pretreatment techniques have been adopted and they are applied either individually or in combined way for enhancement of bio-methanation i.e anaerobic digestion (AD) process. The goal of pretreatment method is to make the cellulose in micro-fibrils available for hydrolysis and improve the rate of hydrolysis. This paper reviews pretreatment techniques including physical, physico-chemical, chemical, biological methods respectively. The various effects of pretreatment on organic solid wastes are discussed separately and pretreatment methods have been compared on the basis of cost, efficiency and suitability to substrate.
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- 2015
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36. Comparative analysis of endothelial cell loss following phacoemulsification in pupils of different sizes
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Raghudev Bhattacharjee, Rajesh Chandra Kar, Rakesh Maggon, Sandeep Shankar, Shyamal Roy, and Vivek Sharma
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Male ,medicine.medical_specialty ,Visual acuity ,Time Factors ,genetic structures ,medicine.medical_treatment ,Visual Acuity ,Intraocular lens ,Cell Count ,Slit Lamp Microscopy ,Group A ,Pupil ,Group B ,Corneal Diseases ,03 medical and health sciences ,0302 clinical medicine ,Postoperative Complications ,lcsh:Ophthalmology ,Double-Blind Method ,Ophthalmology ,medicine ,Humans ,030212 general & internal medicine ,Prospective Studies ,Prospective cohort study ,Aged ,Nuclear sclerosis ,Phacoemulsification ,business.industry ,Endothelium, Corneal ,endothelial cell count ,pupillary size ,Middle Aged ,eye diseases ,lcsh:RE1-994 ,030221 ophthalmology & optometry ,Female ,Original Article ,sense organs ,medicine.symptom ,business ,Follow-Up Studies - Abstract
Purpose: To compare Endothelial cell(EC) loss following Phacoemulsification (PKE) in pupils of different sizes. Methods: A prospective double masked observational study in which a total of 150 eyes of 150 patients between 50 & 70 years of age with senile cataract of nuclear sclerosis grade II were enrolled. Patients were allocated into three groups of 50 eyes each in Group A (pupil size 7 mm). Pupillary size was measured by determining the height of slit on slit-lamp biomicroscope examination. PKE was done by the same expert surgeon using vertical chop technique and a foldable intraocular lens was implanted in the capsular bag. Corneal EC count and pachymetry were performed twice and average of 2 readings was taken for the purpose of this study. Measurements were taken preoperatively and postoperatively on day 1, day 7 and day 30. Results: The mean EC count loss on postoperative day 1 in Group A was 19.45%, Group B 14.89%, Group C 10.19% with statistical significant difference between Group A and Group B, as also Group A and Group C. The difference was not significant between Group B and Group C, though there was a fall in EC count in Group C as well. Increase in corneal thickness on postoperative day 1 in group A was 5.43%, Group B 3.55%, Group C 2.14% with statistical significant difference between Group A and Group B, as also Group A and Group C with no difference in Group B and Group C. Conclusion: PKE done in eyes with maximal pupillary dilatation of 5 mm at the end of one month.
- Published
- 2017
37. Microscale modelling of multiple and higher-order deformation twinning
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Albrecht Bertram, Shyamal Roy, and Rainer Glüge
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Physics ,Condensed matter physics ,Mechanical Engineering ,Lattice (order) ,Solid mechanics ,Computational Mechanics ,Nanotechnology ,Crystallographic slip ,Crystal twinning ,Single crystal ,Microscale chemistry ,A titanium - Abstract
We present a framework for the microscale modelling of higher-order deformation twinning. For this purpose, it is important to track the evolution of the lattice orientation as well as the deformation at each material point. The model is applied to a titanium single crystal with the \({\langle \bar 1 0 1 1 \rangle \{\bar 1 0 1 2\}}\) and \({\langle \bar 1 \bar 1 2 3 \rangle \{11\bar22\}}\) twinning modes.
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- 2014
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38. Ceria promoted γ-Al2O3 supported platinum catalyst for catalytic wet air oxidation of oxalic acid: kinetics and catalyst deactivation
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Shyamal Roy and Anil K. Saroha
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Chemistry ,General Chemical Engineering ,Catalyst support ,Oxalic acid ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Catalyst poisoning ,Catalysis ,chemistry.chemical_compound ,Chemisorption ,Carbon nanotube supported catalyst ,Wet oxidation ,Platinum - Abstract
Alumina-supported platinum catalysts were prepared for catalytic wet air oxidation of oxalic acid. Addition of ceria as a promoter to alumina supported catalyst enhanced the catalytic activity, and significant conversions of about 74% were obtained at 363 K and atmospheric pressure. The long-term deactivation resistance of the ceria promoted Pt/Al2O3 catalyst is higher than that of the Pt/Al2O3 catalyst. A deactivation study of the catalysts was carried out using selective chemisorption, X-ray powder diffraction (XRD) patterns and total organic carbon (TOC) analysis. The deactivation observed with the Pt/Al2O3 catalyst was attributed to the over oxidation of the surface of platinum by molecular oxygen and coke deposition on the catalyst surface.
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- 2014
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39. Hydrogenation of Toluene on Zirconium-Modified Hexagonal Molecular Sieve Supported Platinum and Palladium Catalysts
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Shyamal Roy and Siddhartha Datta
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Zirconium ,Materials science ,General Chemical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Molecular sieve ,Toluene ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,chemistry ,Platinum ,Mesoporous material ,Nuclear chemistry ,Palladium ,Space velocity - Abstract
Hexagonal molecular sieve (HMS) and Zr-HMS materials were synthesized and employed as supports for preparation of hydrogenation catalyst. Supports and catalysts were characterized by using inductively coupled plasma atomic emission spectroscopy, X-ray diffraction, energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), temperature-programmed desorption, Brunauer–Emmett–Teller surface area, and CO chemisorptions techniques. Results from SEM and EDX confirm the hexagonally ordered mesoporous structure and incorporation of Zr into the HMS support, respectively. The detailed kinetic study of hydrogenation of toluene over Pt(0.15wt%)–Pd(0.15wt%)/HMS and Pt(0.15wt%)–Pd(0.15wt%)/Zr-HMS was performed in a continuous-upflow stainless steel catalytic fixed bed reactor at varied weight hourly space velocity (WHSV), hydrogen partial pressure, and temperature. It was observed that toluene conversion was increased on increasing H2 partial pressure and decreased with increasing WHSV. The conversion i...
- Published
- 2013
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40. Antimalarial drug resistance in Bangladesh, 1996–2012
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Jahirul Karim, Harald Noedl, Shyamal Roy, Nazrul Islam, Ubydul Haque, Waziul Haque, and Gregory E. Glass
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medicine.medical_specialty ,Primaquine ,Plasmodium falciparum ,Drug Resistance ,Drug resistance ,Pharmacology ,Antimalarials ,chemistry.chemical_compound ,Chloroquine ,Internal medicine ,parasitic diseases ,Humans ,Medicine ,Malaria, Falciparum ,Bangladesh ,Quinine ,biology ,business.industry ,Mefloquine ,Public Health, Environmental and Occupational Health ,General Medicine ,biology.organism_classification ,medicine.disease ,Treatment Outcome ,Infectious Diseases ,chemistry ,Artesunate ,Parasitology ,business ,Malaria ,medicine.drug - Abstract
Malaria remains an important health problem in Bangladesh, with approximately 14 million people at risk. Antimalarial drug resistance is a major obstacle to the control of malaria in endemic countries. In 2012, Bangladesh reported an estimated 29 522 malaria episodes, of which 94% were reported as being caused by Plasmodium falciparum. In this study, we reviewed and summarized antimalarial drug resistance data from Bangladesh published until June 2013. We searched published sources for data referring to any type of P. falciparum drug resistance (in vivo, in vitro, or molecular) and found 169 articles published in peer-reviewed journals. Of these, 143 articles were excluded because they did not meet our inclusion criteria. After detailed review of the remaining 26 articles, 14 were selected for evaluation. Published studies indicate that P. falciparum shows varying levels of resistance to chloroquine, mefloquine and sulfadoxine-pyrimethamine. Combination therapy of chloroquine and primaquine has proven ineffective and combinations of sulfadoxine-pyrimethamine with either quinine or chloroquine have also shown poor efficacy. Recent studies indicate that artemisinin derivatives, such as artesunate, remain highly efficacious in treating P. falciparum malaria. Available data suggest that artemisinins, quinine, doxycyline, mefloquine-artesunate and azithromycin-artesunate combination therapy remain efficacious in the treatment of P. falciparum malaria in Bangladesh.
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- 2013
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41. Catalytic Wet Air Oxidation of Oxalic Acid Using Ceria-promoted Pt/Al2O3
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Shyamal Roy and Anil K. Saroha
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Thermogravimetric analysis ,chemistry.chemical_compound ,Hydrogen ,Atmospheric pressure ,Chemistry ,Chemisorption ,General Chemical Engineering ,Oxalic acid ,Inorganic chemistry ,chemistry.chemical_element ,Activation energy ,Wet oxidation ,Catalysis - Abstract
Catalytic wet air oxidation of oxalic acid using ceria-promoted Pt/Al2O3 catalyst was studied in a glass reactor operated at atmospheric pressure. The catalyst was prepared by the excess solution impregnation method and the catalyst characterization was performed using scanning electron microscopy, nitrogen adsorption, hydrogen chemisorption and thermogravimetric analysis techniques. The effect of initial concentration of oxalic acid, air flow rate, reaction temperature and ceria loading on oxidation of oxalic acid was investigated. The activation energy was found to be 42 kJ/mol and a rate equation was proposed for the oxidation of oxalic acid. Catalyst deactivation and regeneration were studied. It was noticed that the presence of ceria reduced the deactivation of the Pt/Al2O3 catalyst.
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- 2011
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42. Phtophysical processes involved within the bichromophoric system 9-benzotriazole-1-ylmethyl-9H-carbazole and its role as an artificial photosynthetic device
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Joydeep Chowdhury, Sanjib Ghosh, Asish De, Tapas Misra, Shyamal Roy Chaudhury, Tapan Ganguly, and Paulami Mandal
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Photosynthetic reaction centre ,Acetonitriles ,Benzotriazole ,Photochemistry ,Carbazole ,Carbazoles ,Temperature ,Hydrogen-Ion Concentration ,Excimer ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Photoexcitation ,Kinetics ,chemistry.chemical_compound ,Benzonitrile ,Spectrometry, Fluorescence ,chemistry ,Excited state ,Benzothiazoles ,Photosynthesis ,Acetonitrile ,Instrumentation ,Spectroscopy - Abstract
From both steady state and fluorescence lifetime measurements it reveals that due to photoexcitation of benzotriazole (BZ) part of the bichromophore, 9(1-H-benzotriazole-lylmethyl)-9H-carbazole (BHC), singlet–singlet energy transfer takes place to populate the lowest excited singlet of carbazole (CZ). CZ, thus being excited indirectly via energy transfer process, undergoes strong charge transfer (CT) reaction with the surrounding polar medium acetonitrile (ACN). On the other hand, very weak CT band was apparent when CZ part, within BHC, was directly excited. In less polar tetrahydrofuran (THF) and polar benzonitrile (BN) environment, lack of formation of CT band strongly suggests in favor of the electron-accepting behavior of ACN. Moreover, by measuring the emission spectra of BHC in microcrystals and of 30 bilayers mixed LB film at high mole fraction of BHC molecules, the possibility of excimer formation or aggregation has been ruled out. Thus, BHC, when dissolved in ACN, acts as a triad system of BZ–CZ–ACN where BZ acts as an antenna molecule and CZ as a reaction center. The possible role of the bichromophoric system BHC as an artificial photosynthetic or solar energy conversion device has been hinted.
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- 2007
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43. Overcoming Drug-Resistant Cancer by a Newly Developed Copper Chelate through Host-Protective Cytokine-Mediated Apoptosis
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Soumitra Kumar Choudhuri, S. Majumder, Shyamal Roy, Thomas Efferth, Smarajit Pal, Jayati Mookerjee Basu, Tania Das, Rathindra Nath Baral, Jaydip Biswas, Sanghamitra Raha, Sankar Bhattacharyya, P. Dutta, Gourisankar Sa, Pratima Mukherjee, and Ananda Mookerjee
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Cancer Research ,medicine.medical_treatment ,Antineoplastic Agents ,Apoptosis ,Biology ,Peripheral blood mononuclear cell ,Ehrlich ascites carcinoma ,Mice ,Cell Line, Tumor ,Neoplasms ,medicine ,Animals ,Humans ,Carcinoma, Ehrlich Tumor ,Cell Proliferation ,Chelating Agents ,Immunotherapy ,Drug Resistance, Multiple ,Cytokine ,Oncology ,Doxorubicin ,Drug Resistance, Neoplasm ,Cancer cell ,Immunology ,Leukocytes, Mononuclear ,Cancer research ,Cytokines ,Tumor necrosis factor alpha ,Lymph Nodes ,Copper ,Neoplasm Transplantation ,Spleen ,Ex vivo - Abstract
Purpose: Previously, we have synthesized and characterized a novel Cu(II) complex, copper N-(2-hydroxy acetophenone) glycinate (CuNG). Herein, we have determined the efficacy of CuNG in overcoming multidrug-resistant cancer using drug-resistant murine and human cancer cell lines.Experimental Design: Action of CuNG following single i.m. administration (5 mg/kg body weight) was tested in vivo on doxorubicin-resistant Ehrlich ascites carcinoma (EAC/Dox)–bearing mice and doxorubicin-resistant sarcoma 180–bearing mice. Tumor size, ascitic load, and survival rates were monitored at regular intervals. Apoptosis of cancer cells was determined by cell cycle analysis, confocal microscopy, Annexin V binding, and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling assay ex vivo. IFN-γ and tumor necrosis factor-α were assayed in the culture supernatants of in vivo and in vitro CuNG-treated splenic mononuclear cells from EAC/Dox-bearing mice and their apoptogenic effect was determined. Source of IFN-γ and changes in number of T regulatory marker-bearing cells in the tumor site following CuNG treatment were investigated by flow cytometry. Supernatants of in vitro CuNG-treated cultures of peripheral blood mononuclear cells from different drug-insensitive cancer patients were tested for presence of the apoptogenic cytokine IFN-γ and its involvement in induction of apoptosis of doxorubicin-resistant CEM/ADR5000 cells.Results: CuNG treatment could resolve drug-resistant cancers through induction of apoptogenic cytokines, such as IFN-γ and/or tumor necrosis factor-α, from splenic mononuclear cells or patient peripheral blood mononuclear cells and reduce the number of T regulatory marker-bearing cells while increase infiltration of IFN-γ-producing T cells in the ascetic tumor site.Conclusion: Our results show the potential usefulness of CuNG in immunotherapy of drug-resistant cancers irrespective of multidrug resistance phenotype.
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- 2006
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44. Understanding India from a Business Perspective: Opportunities and Challenges for MNCs
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Ashok Rao, D V R Seshadri, Anand Shah, Shyamal Roy, Ravi Viswanathan, Achal Raghavan, Ajay Mookerjee, Rakesh Makhija, J. Ramachandran, Arun Vora, Venkatesh Mysore, and L C Jain
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Government ,Liberalization ,business.industry ,General Decision Sciences ,Information technology ,General Business, Management and Accounting ,nobody ,Management ,Resilience (organizational) ,Market economy ,Multinational corporation ,Position (finance) ,Business ,Tertiary sector of the economy - Abstract
India has, over the last decade, achieved a position of pre-eminence in many spheres of economic activity, most notably in information technology, business process outsourcing, and various other service industries and also increasingly in manufacturing. At the time when the country was liberalized in the early 90s, nobody thought that such a spectacular performance by the Indian industry would be possible only 15 years later. In fact, during several years immediately following the liberalization of the Indian economy, the common refrain of Indian industrialists to the Government of India was for a ‘level playing field.’ The speed with which the Indian industry has adjusted to these cataclysmic changes in the environment is beyond the wildest expectations of industry watchers and pundits. The Indian industry has, by and large, shown resilience in standing its own ground. Many Indian companies have gone on to take their rightful positions in the world arena. Some of them have even emerged as world leaders in their respective domains. The tide seems to have turned a full circle with many multinational companies (MNCs) with head offices overseas increasingly looking at setting up local operations in India to harness the value that the country delivers.
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- 2006
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45. INHIBITION OF EARLY DNA-DAMAGE AND CHROMOSOMAL ABERRATIONS BY TRIANTHEMA PORTULACASTRUM L. IN CARBON TETRACHLORIDE-INDUCED MOUSE LIVER DAMAGE
- Author
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Soumen Pradhan, Aloke Sarkar, Indranil Mukhopadhyay, Malay Chatterjee, Shyamal Roy, and Subrata K. Bose
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Male ,DNA damage ,Iron ,Mice, Inbred Strains ,Pharmacology ,Magnoliopsida ,Mice ,Basal (phylogenetics) ,chemistry.chemical_compound ,Inbred strain ,Animals ,Chromosome Aberrations ,Ethanol ,biology ,Carbon Tetrachloride Poisoning ,Deoxyribose ,Liver Diseases ,DNA ,Cell Biology ,General Medicine ,biology.organism_classification ,Trianthema portulacastrum ,Biochemistry ,chemistry ,Acute Disease ,Chronic Disease ,Solvents ,Carbon tetrachloride ,Chemical and Drug Induced Liver Injury ,DNA Damage - Abstract
The underlying molecular mechanisms of the antihepatotoxic activity of Trianthema portulacastrum by monitoring its effect on mouse liver DNA-chain break, sugar-base damage and chromosomal aberrations, during chronic or acute treatment with carbon tetrachloride (CCl(4)) have been studied. Daily oral feeding with the ethanolic extract (150 mg/kg basal diet, per os) was given 2 weeks before CCl(4)treatment and continued until the end of the experiment (13 weeks). T. portulacastrum extract offer unique protection (P< 0.05-0. 001) against the induction of liver-specific structural-type chromosomal anomalies 15, 30 or 45 days after the last CCl(4)insult, compared to control mice. This was further evidenced by extract-mediated protection (15 days prior feeding following a single necrogenic dose of CCl(4)) of the generation of DNA chain-break and Fe-sugar-base damage assays. The observed hepatoprotective mechanism could be due to its ability to counteract oxidative injury to DNA in the liver of mouse.
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- 1999
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46. Characterizing the spatial and temporal variation of malaria incidence in Bangladesh, 2007
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Heidi Reid, Nazrul Islam, Shyamal Roy, Ubydul Haque, and Archie C. A. Clements
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medicine.medical_specialty ,Plasmodium falciparum ,Time Factors ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,Plasmodium vivax ,Population ,Temporal ,Risk Assessment ,Bayesian ,lcsh:Infectious and parasitic diseases ,symbols.namesake ,Risk Factors ,parasitic diseases ,medicine ,Malaria, Vivax ,Animals ,Humans ,Spatial ,lcsh:RC109-216 ,Poisson regression ,Malaria, Falciparum ,education ,education.field_of_study ,Bangladesh ,biology ,Ecology ,Incidence (epidemiology) ,Research ,Incidence ,Seasonality ,biology.organism_classification ,medicine.disease ,Malaria ,Geography ,Infectious Diseases ,Tropical medicine ,symbols ,Parasitology ,Topography, Medical ,Risk assessment ,Demography - Abstract
Background Malaria remains a significant health problem in Bangladesh affecting 13 of 64 districts. The risk of malaria is variable across the endemic areas and throughout the year. A better understanding of the spatial and temporal patterns in malaria risk and the determinants driving the variation are crucial for the appropriate targeting of interventions under the National Malaria Control and Prevention Programme. Methods Numbers of Plasmodium falciparum and Plasmodium vivax malaria cases reported by month in 2007, across the 70 endemic thanas (sub-districts) in Bangladesh, were assembled from health centre surveillance reports. Bayesian Poisson regression models of incidence were constructed, with fixed effects for monthly rainfall, maximum temperature and elevation, and random effects for thanas, with a conditional autoregressive prior spatial structure. Results The annual incidence of reported cases was 34.0 and 9.6 cases/10,000 population for P. falciparum and P. vivax respectively and the population of the 70 malaria-endemic thanas was approximately 13.5 million in 2007. Incidence of reported cases for both types of malaria was highest in the mountainous south-east of the country (the Chittagong Hill Tracts). Models revealed statistically significant positive associations between the incidence of reported P. vivax and P. falciparum cases and rainfall and maximum temperature. Conclusions The risk of P. falciparum and P. vivax was spatially variable across the endemic thanas of Bangladesh and also highly seasonal, suggesting that interventions should be targeted and timed according to the risk profile of the endemic areas. Rainfall, temperature and elevation are major factors driving the spatiotemporal patterns of malaria in Bangladesh.
- Published
- 2012
47. Photophysical processes involved within the anisole-thioindoxyl dyad system
- Author
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Tarun Kanti Pradhan, Tapan Ganguly, Shyamal Roy Chaudhury, Sudeshna Bhattacharya, and Avijit K. De, and Asish De
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Solvent ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Singlet state ,Physical and Theoretical Chemistry ,Energy minimization ,Anisole ,Electrochemistry ,Photochemistry ,Redox ,Excitation ,Photoinduced electron transfer - Abstract
The photophysical properties and the nature of the photoinduced electron transfer (PET) reactions within a synthesized anisole (A)-thioindoxyl (T) dyad system (24MBTO) have been studied by electrochemical, steady-state, and time-resolved spectroscopic techniques. Computations on the dyad were performed both in gas phase as well as solvent environment by TD-DFT method with B3LYP density function. The geometry optimization calculation of 24MBTO was done by 6-311G(d,p) basis function set implemented in the Gaussian package. The theoretical values of singlet vertical excitation energies were found to correlate well with the experimentally observed ones. The electrochemical measurements indicate the possibility of occurrence of PET reactions within 24MBTO between the linked redox centers A and T. Both steady-state and time-resolved spectroscopic measurements on the novel synthesized 24MBTO dyad demonstrate the formations of the two types of isomeric species: Z- and E- forms, resulted from the charge separation reactions. From the detailed studies it reveals that the present thioaurone may behave as a versatile photoswitchable system. It has been hinted that the loss process (charge recombination) within 24MBTO could possibly be prevented by incorporating it within the hydrophobic cavity of beta-cyclodextrin (betaCD).
- Published
- 2006
48. Farm tractorisation, productivity and labour employment: A case study of Indian Punjab
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Melvin G. Blase and Shyamal Roy
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Labour economics ,Control (management) ,Economics ,Public policy ,Displacement (orthopedic surgery) ,Development ,Productivity - Abstract
The objective of this paper is to determine the effects of farm tractorisation on output and human labour employment on Punjab farms in India. The residts seem to suggest that, this far, the use of tractors has resulted in higher output and more employment. The authors believe that the threat from farm tractorisation is not all that great; the use of tractors is likely to be confined to certain areas only, and there too, any displacement of labour should be possible to control through appropriate public policies.
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- 1978
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49. Labour‐intensive and capital‐intensive technology in irrigation development
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A. Sunder, Shyamal Roy, and P.S. Rao
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Irrigation ,Rapid expansion ,business.industry ,media_common.quotation_subject ,Development ,Unemployment ,Economics ,Food processing ,Operations management ,Capital intensity ,business ,Industrial organization ,Water Science and Technology ,media_common - Abstract
The need for a rapid expansion in irrigation in India for the purposes of food production is generally accepted. Whether irrigation works can at the same time effectively tackle the country's massive rural unemployment problem is the subject of this paper. Basic planning requirements are outline, and then the complex issues surrounding the choice of labour‐intensive or capital‐intensive technology are discussed. Finally, the kinds of data required before informed decisions can be made are specified.
- Published
- 1987
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