68 results on '"H. Sivaramakrishnan"'
Search Results
2. Stability-Indicating RP-HPLC Method for Assay of Silver Lactate
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V. Srinivasan, H. Sivaramakrishnan, and B. Karthikeyan
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Chemistry ,QD1-999 - Abstract
A simple, economic and time-efficient stability-indicating, reverse-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for analysis of silver lactate in the presence of degradation products generated by decomposition. When silver lactate was subjected to acid hydrolysis, base hydrolysis, oxidative, photolytic, humidity and thermal stress, degradation was observed during base hydrolysis, oxidation, humidity and thermal stress. The drug was found to be stable to other stress conditions. Successful chromatographic condition of the drug from the degradation products formed under stress conditions was achieved on a phenomenex Gemini column with potassium dihydrogen phosphate buffer, pH adjusted to 2.2 with orthophosphoric acid, as mobile phase. The method was validated for linearity, precision, specificity and robustness and can be used for quality-control during manufacture and assessment of the stability of samples of silver lactate. To the best of our knowledge, a validated stability-indicating LC assay method for silver lactate based on lactic acid is reported for the first time.
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- 2011
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3. Mechanisms of charge carrier transport in polycrystalline silicon passivating contacts
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Galleni, L., Fırat, M., Radhakrishnan, H. Sivaramakrishnan, Duerinckx, F., Tous, L., and Poortmans, J.
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- 2021
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4. Single-Event-Transient Resilient Memory for DSP in Space Applications.
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Ne Kyaw Zwa Lwin, H. Sivaramakrishnan, Kwen-Siong Chong, Tong Lin 0001, Wei Shu, and Joseph S. Chang
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- 2018
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5. Synthesis, Characterization, Antimalarial and Anticancer Activities of Few New Amino Analogues of 1,4-Naphthoquinone
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S.S. Sanjay, null Shashiprabha, K. Shridhara, K. Nagarajan, H. Sivaramakrishnan, and B. Arun
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Applied Mathematics ,heterocyclic compounds - Abstract
Present study involves the synthesis, characterization, antimalarial and anticancer activities of some novel substituted amino analogues of 1,4-naphthoquinone. The chloro group present in the key starting materials like 2,3-dichloro-1,4-naphthoquinone (1) and 2-chloro-3-[trans-4-(4-chlorophenyl)- cyclohexyl]-1,4-naphthoquinone (2) was replaced by substituted amines. These analogues were isolated, purified and screened for antimalarial and anticancer activities. A few of the novel compounds were found to possess substantial biological activity and are reasonably potent.
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- 2022
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6. Residential task scheduling under dynamic pricing using the multiple knapsack method.
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N. Kumaraguruparan, H. Sivaramakrishnan, and Sachin S. Sapatnekar
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- 2012
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7. Synthesis of Novel N-(6-(Trifluoromethyl)Pyridin-2-yl)Pyrimidin-4-Amine Analogues
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C. Suneel Manohar, Vijayaparthasarathi Vijayakumar, B. Ravi Shankar, and H. Sivaramakrishnan
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chemistry.chemical_compound ,Trifluoromethyl ,Polymers and Plastics ,chemistry ,Suzuki reaction ,Aryl ,Organic Chemistry ,Materials Chemistry ,Amine gas treating ,Medicinal chemistry - Abstract
A novel series of 2/6-aryl/heteroaryl substituted-N-(6-(trifluoromethyl)pyridin-2-yl)pyrimidin-4-amine analogues have been synthesized from dichloropyrimidines by an initial substitution followed b...
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- 2021
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8. How to accelerate the supply of vaccines to all populations worldwide? Part II: Initial industry lessons learned and detailed technical reflections leveraging the COVID-19 situation
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Mic McGoldrick, Thierry Gastineau, Diane Wilkinson, Cristiana Campa, Norbert De Clercq, Andrea Mallia-Milanes, Olivier Germay, Jyothsna Krishnan, M Van Ooij, Michael P Thien, Peter J. Mlynarczyk, Edward Saltus, Florence Wauters, Philippe Juvin, Didier Clenet, Ana Basso, Nora Dellepiane, Sonia Pagliusi, Monique Collaço de Moraes Stávale, Venkatraman H Sivaramakrishnan, and Samir Desai
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Vaccines ,Infectious Diseases ,General Veterinary ,General Immunology and Microbiology ,SARS-CoV-2 ,Vaccination ,Public Health, Environmental and Occupational Health ,Molecular Medicine ,COVID-19 ,Humans ,Pandemics - Abstract
Vaccine discovery and vaccination against preventable diseases are one of most important achievements of the human race. While medical, scientifictechnological advancements have kept in pace and found their way into treatment options for a vast majority of diseases, vaccines as a prevention tool in the public health realm are found languishing in the gap between such innovations and their easy availability/accessibility to vulnerable populations. This paradox has been best highlighted during the unprecedented crisis of the COVID-19 pandemic. As part of a two series publication on the vaccine industry's view on how to accelerate the availability of vaccines worldwide, this paper offers a deep dive into detailed proposals to enable this objective. These first-of-its-kind technical proposals gleaned from challenges and learnings from the COVID-19 pandemic are applicable to vaccines that are already on the market for routine pathogens as well as for production of new(er) vaccines for emerging pathogens with a public health threat potential. The technical proposals offer feasible and sustainable solutions in pivotal areas such as process validation, comparability, stability, post-approval changes, release testing, packaging, genetically modified organisms and variants, which are linked to manufacturing and quality control of vaccines. Ultimately these proposals aim to ease high regulatory complexity and heterogeneity surrounding the manufacturingdistribution of vaccines, by advocating the use of (1) Science and Risk based approaches, (2) global regulatory harmonization, (3) use of reliance, work-sharing, and recognition processes and (4) digitalization. Capitalizingcollaborating on such new-world advancements into the science of vaccines will eventually benefit the world by turning vaccines into vaccination, ensuring the health of everyone.
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- 2021
9. A catalyst free synthesis of 8, 9, 11-trihalo-5 H -benzofuro[3,2- c ]carbazol-10-ols
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Vijayaparthasarathi Vijayakumar, K. Nagarajan, H. Sivaramakrishnan, and B. Ravi Shankar
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Range (particle radiation) ,010405 organic chemistry ,Stereochemistry ,Chemistry ,Organic Chemistry ,Chloranil ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Medicinal chemistry ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Drug Discovery - Abstract
8, 9, 11-Trichloro-5 H -benzofuro[3,2- c ]carbazol-10-ol analogues have been synthesized by treating 2,3-dihydro-1 H -carbazol-4(9 H )-one with chloranil/fluoranil without any catalyst and is found to be applicable across a range of carbazolone substrates. A possible mechanism has been proposed.
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- 2017
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10. Single-Event-Transient Resilient Memory for DSP in Space Applications
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Joseph S. Chang, Ne Kyaw Zwa Lwin, H. Sivaramakrishnan, Tong Lin, Kwen-Siong Chong, Wei Shu, School of Electrical and Electronic Engineering, and 2018 IEEE 23rd International Conference on Digital Signal Processing (DSP)
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Triple modular redundancy ,Digital signal processor ,Computer science ,Hardware_PERFORMANCEANDRELIABILITY ,02 engineering and technology ,01 natural sciences ,Computer Architecture ,law.invention ,Reduction (complexity) ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Transient (computer programming) ,Static random-access memory ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,Digital signal processing ,Hardware_MEMORYSTRUCTURES ,010308 nuclear & particles physics ,business.industry ,020208 electrical & electronic engineering ,Transistor ,CMOS ,Embedded system ,Electrical and electronic engineering [Engineering] ,SRAM Cells ,business - Abstract
We present a radiation-hardened-by-design (RHBD) memory design that mitigates Single-Event-Transients (SETs), Single-Event-Upsets (SEUs) and Dual-Event-Upsets (DEUs), hence significantly enhancing the reliability of digital signal processors (DSPs) for space applications. We achieve these attributes by combining a Triple-Interlocked Cell (TICE) SRAM cell array and a Triple Modular Redundancy (TMR) voter. The TICE SRAM cells therein self-correct SEUs and DEUs. The TMR voter eliminates SETs. Our proposed RHBD TICE SRAM cells integrated with the TMR voter are also hardened by the layout/sizing RHBD practices. By means of the 128×9-bit memory implementation @ 65nm CMOS, we show that our memory design is inherent SEUand DEU-tolerant, and has 94.83% SET reduction and 92.05% Triple-Event-Upset (TEU) reduction when compared to the memory design embodying the 8-transistor (8-T) SRAM cells. MOE (Min. of Education, S’pore) Accepted version
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- 2018
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11. Synthesis of N-(6-(4-(Piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide Derivatives for the Treatment of Metabolic Syndrome
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Nabajyoti Deka, Swapnil Bajare, Anagha Damre, Amrutha Nair, Dharmeshkumar Patel, Rosalind Adaikalasamy Marita, H. Sivaramakrishnan, Jessy Anthony, Chandan Wilankar, Chandrika B-Rao, and Shivaprakash Jagalur Mutt
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Article Subject ,endocrine system diseases ,business.industry ,Insulin ,medicine.medical_treatment ,lcsh:RM1-950 ,Metabolic disorder ,Type 2 Diabetes Mellitus ,Pharmacology ,medicine.disease ,Biochemistry ,lcsh:Therapeutics. Pharmacology ,Insulin resistance ,High plasma ,Drug Discovery ,Pparγ ligand ,medicine ,Molecular Medicine ,Metabolic syndrome ,Adverse effect ,business ,Research Article - Abstract
Metabolic syndrome is a widely prevalent multifactorial disorder associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. High plasma levels of insulin and glucose due to insulin resistance are a major component of the metabolic disorder. Thiazolidinediones (TZDs) are potent PPARγ ligand and used as insulin sensitizers in the treatment of type 2 diabetes mellitus. They are potent insulin-sensitizing agents but due to adverse effects like hepatotoxicity, a safer alternative of TZDs is highly demanded. Here we report synthesis of N-(6-(4-(piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide derivatives as an alternate remedy for insulin resistance.
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- 2013
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12. Design and synthesis of non-TZD peroxisome proliferator-activated receptor γ (PPARγ) modulator
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H. Sivaramakrishnan, Sujit Kaur Bhumra, Dharmeshkumar Patel, Amrutha Nair, Jessy Anthony, Chandrika B-Rao, Nabajyoti Deka, and Mahesh Uravane
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chemistry.chemical_classification ,endocrine system diseases ,chemistry ,Adipogenesis ,Organic Chemistry ,Antihyperglycemic Agents ,Pharmacology toxicology ,Peroxisome proliferator-activated receptor ,General Pharmacology, Toxicology and Pharmaceutics ,Pharmacology ,Peroxisome ,Receptor - Abstract
Thiazolidinediones (TZDs) are an important class of compound used for the treatment of type 2 diabetes, targeting the peroxisome proliferator-activated receptor γ (PPARγ). Drug-induced hepatotoxicity, edema, and weight gain are the main concerns associated with TZDs. It was unclear whether the side effects observed are target mediated or compound mediated, but most of the TZDs activate PPARγ. This obliged developing of a new diverse class of ligands as antihyperglycemic agents including non-TZD PPAR ligands that could be highly effective, safe, and devoid of side effects. Here, we report the design and synthesis of N-(5-chloro-6-((1-phenylpiperidin-4-yl)oxy)pyridin-3-yl)benzenesulfonamide derivatives as non-TZD PPARγ modulators.
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- 2013
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13. Lead optimization of isocytosine-derived xanthine oxidase inhibitors
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Usha Ghosh, Smriti Khanna, Asha Kulkarni-Almeida, Ankita Srivastava, Komal Bajaj, Chandrika B-Rao, Prashant Tannu, Ashish P. Keche, Kumar V.S. Nemmani, Pranay Shah, Sandeep Burudkar, Rajiv Sharma, Yogesh Suresh Ahire, H. Sivaramakrishnan, Amol Dixit, Anagha Damre, and Nitin J. Deshmukh
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Models, Molecular ,Xanthine Oxidase ,Clinical Biochemistry ,Administration, Oral ,Pharmaceutical Science ,Pharmacology ,Biochemistry ,Cytosine ,Inhibitory Concentration 50 ,chemistry.chemical_compound ,In vivo ,Catalytic Domain ,Drug Discovery ,Animals ,Isocytosine ,Enzyme Inhibitors ,Xanthine oxidase ,Molecular Biology ,Molecular Structure ,Organic Chemistry ,Rats ,Enzyme Activation ,stomatognathic diseases ,chemistry ,Models, Animal ,Molecular Medicine ,Lead compound - Abstract
We report our attempts at improving the oral efficacy of low-nanomolar inhibitors of xanthine oxidase from isocytosine series through chemical modifications. Our lead compound had earlier shown good in vivo efficacy when administered intraperitoneally but not orally. Several modifications are reported here which achieved more than twofold improvement in exposure. A compound with significant improvement in oral efficacy was also obtained.
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- 2013
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14. Improvement of seed layer smoothness for epitaxial growth on porous silicon
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K. Van Nieuwenhuysen, Radhakrishnan H. Sivaramakrishnan, Mario Gonzalez, Valerie Depauw, J. Poortmans, Ivan Gordon, and Roberto Martini
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Materials science ,Silicon ,chemistry.chemical_element ,Surface finish ,Substrate (electronics) ,Porous silicon ,Epitaxy ,law.invention ,chemistry ,law ,Solar cell ,Composite material ,Layer (electronics) ,FOIL method - Abstract
In the last decades many techniques have been proposed to manufacture thin (Several parameters can be adjusted to change the morphology and, hence, the properties of the porous layer, both in the porous silicon formation and the succeeding thermal treatment. This work focuses on the effect of the parameters that control the porous silicon formation on the structure of the porous silicon layer after annealing and, more specifically, on the roughness of the top surface. The reported analysis shows how the roughness of the seed layer can be reduced to improve the quality of the epitaxial growth.
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- 2013
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15. Detection, isolation and characterization of principle synthetic route indicative impurity in telmisartan
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B. Karthikeyan, H. Sivaramakrishnan, and V. Srinivasan
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Chemistry(all) ,General Chemical Engineering ,Characterization ,Analytical chemistry ,030204 cardiovascular system & hematology ,Mass spectrometry ,01 natural sciences ,High-performance liquid chromatography ,lcsh:Chemistry ,03 medical and health sciences ,0302 clinical medicine ,Impurity ,medicine ,Telmisartan ,Spectroscopy ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,ComputingMilieux_MISCELLANEOUS ,Active ingredient ,Chromatography ,Chemistry ,010401 analytical chemistry ,General Chemistry ,MS ,Bulk drug ,NMR ,0104 chemical sciences ,Characterization (materials science) ,lcsh:QD1-999 ,Chemical Engineering(all) ,HPLC ,medicine.drug - Abstract
An unknown impurity was detected in the telmisartan bulk drug (active pharmaceutical ingredient – API) using an isocratic reversed-phase high performance liquid chromatography (HPLC). This impurity was isolated by preparative HPLC. Spectral data of the isolated impurity were collected. Based on the spectral data deriving from two dimensional nuclear magnetic spectroscopy (2D-NMR) and mass spectrometry (MS), the impurity was characterized as “methyl 4′,4′-dibromo methyl biphenyl-2-carboxylate”. The arrived structure was further confirmed by theoretical studies.
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- 2016
16. Synthesis of N-(5-chloro-6-(quinolin-3-yloxy)pyridin-3-yl)benzenesulfonamide derivatives as non-TZD peroxisome proliferator-activated receptor γ (PPARγ) agonist
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Swapnil Bajare, Anagha Damre, Nabajyoti Deka, Amrutha Nair, Dharmeshkumar Patel, Chandrika Rao, Rosalind Adaikalasamy Marita, H. Sivaramakrishnan, and Jessy Anthony
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Models, Molecular ,medicine.medical_specialty ,endocrine system diseases ,Peroxisome proliferator-activated receptor ,Adipose tissue ,Carbohydrate metabolism ,Structure-Activity Relationship ,chemistry.chemical_compound ,Insulin resistance ,Internal medicine ,Adipocyte ,Drug Discovery ,medicine ,Humans ,Receptor ,Pharmacology ,chemistry.chemical_classification ,Sulfonamides ,Dose-Response Relationship, Drug ,Molecular Structure ,Organic Chemistry ,General Medicine ,medicine.disease ,PPAR gamma ,HEK293 Cells ,Endocrinology ,Nuclear receptor ,chemistry ,Adipogenesis ,Quinolines - Abstract
The thiazolidinediones (TZDs) are a class of oral antidiabetic drugs that improve insulin sensitivity in patients with type 2 diabetes. Although the mechanism by which the TZDs lower insulin resistance is unclear, they are known to target the peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor. Ligands for PPARγ regulate adipocyte production and secretion of fatty acids as well as glucose metabolism, resulting in increased insulin sensitivity in adipose tissue, liver, and skeletal muscle. However, TZDs have several adverse effects, including weight gain and liver toxicity. Herein we report identification of non-TZD PPARγ agonists which exhibit beneficial effects similar to that of TZDs in animal models, but without the associated adverse effects.
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- 2012
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17. Identification of novel isocytosine derivatives as xanthine oxidase inhibitors from a set of virtual screening hits
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Rajiv Sharma, Smriti Khanna, Umakant Ashok Bahirat, Asha Kulkarni-Almeida, Pranay Shah, Amol Dixit, Kamlesh V. Katkar, Kumar V.S. Nemmani, Ashish P. Keche, H. Sivaramakrishnan, Vaidehi Korde, Chandrika B-Rao, Ankita Srivastava, Nitin J. Deshmukh, Manoja K. Brahma, Lalit S. Doshi, and Usha Ghosh
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Male ,Xanthine Oxidase ,Clinical Biochemistry ,Pharmaceutical Science ,Hyperuricemia ,Pharmacology ,Biochemistry ,Rats, Sprague-Dawley ,Cytosine ,Structure-Activity Relationship ,chemistry.chemical_compound ,In vivo ,Drug Discovery ,medicine ,Animals ,Computer Simulation ,Isocytosine ,Enzyme Inhibitors ,Xanthine oxidase ,Molecular Biology ,Virtual screening ,Organic Chemistry ,medicine.disease ,Xanthine ,Rats ,Enzyme Activation ,Oxonic Acid ,chemistry ,Docking (molecular) ,Molecular Medicine ,Uric acid - Abstract
In recent years, xanthine oxidase has emerged as an important target not only for gout but also for cardiovascular and metabolic disorders involving hyperuricemia. Contrary to popular belief, recent clinical trials with uricosurics have demonstrated that enhanced excretion of uric acid is, by itself, not adequate to treat hyperuricemia; simultaneous inhibition of production of uric acid by inhibition of xanthine oxidase is also important. Virtual screening of in-house synthetic library followed by in vitro and in vivo testing led to the identification of a novel scaffold for xanthine oxidase inhibition. In vitro activity results corroborated the results from molecular docking studies of the virtual screening hits. The isocytosine scaffold maintains key hydrogen bonding and pi-stacking interactions in the deep end of the xanthine-binding pocket, which anchors it in an appropriate pose to inhibit binding of xanthine and shows promise for further lead optimization using structure-based drug design approach.
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- 2012
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18. STRESS DEGRADATION STUDIES ON MEBEVERINE HYDROCHLORIDE AND DEVELOPMENT OF A VALIDATED STABILITY INDICATING UPLC METHOD
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V. Srinivasan, T. S. Balaji, B. Karthikeyan, H. Sivaramakrishnan, and S. Vijayabaskar
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Chromatography ,Clinical Biochemistry ,Pharmaceutical Science ,Reversed-phase chromatography ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,chemistry.chemical_compound ,Hydrolysis ,chemistry ,Forced degradation ,medicine ,Degradation (geology) ,Thermal stability ,Mebeverine ,Acetonitrile ,medicine.drug - Abstract
A simple, economic, and time-efficient stability-indicating, reverse-phase ultra-performance liquid chromatographic (RP-UPLC) method has been developed for analysis of mebeverine hydrochloride in the presence of both impurities and degradation products generated by forced degradation. When mebeverine hydrochloride was subjected to acid hydrolytic, oxidative, base hydrolysis, photolytic, and thermal stress, degradation was observed only in base hydrolysis. The drug was found to be stable to other stress conditions. Successful chromatographic separation of the drug from impurities formed during synthesis and from degradation products formed under stress conditions was achieved on a Waters Acquity C18, 50 mm x 2.1 mm, 1.7 µ particle size column, UV detection at 225 nm and a gradient elution of orthophosphoric acid and acetonitrile as the mobile phase. The method was validated for specificity, precision, linearity, accuracy, and robustness and can be used for quality control during manufacture and for assessm...
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- 2011
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19. Novel diarylheptanoids as inhibitors of TNF-α production
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Dattatray Maruti More, Firuza Kharas, Sapna Parikh, Lyle C. Fonseca, H. Sivaramakrishnan, Sameer Dhuru, Vijaya Nadar, Roda Dalal, Kiran Hirbhagat, Dilip Bhedi, Ram A. Vishwakarma, Dnyaneshwar Gophane, and Prashant Vadnal
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Lipopolysaccharide ,medicine.medical_treatment ,Clinical Biochemistry ,Anti-Inflammatory Agents ,Pharmaceutical Science ,Pharmacology ,Biochemistry ,Peripheral blood mononuclear cell ,Mice ,chemistry.chemical_compound ,Diarylheptanoids ,Drug Discovery ,medicine ,Animals ,Humans ,Molecular Biology ,Cells, Cultured ,Molecular Structure ,Tumor Necrosis Factor-alpha ,Organic Chemistry ,Diarylheptanoid ,Biological activity ,Cytokine ,Gene Expression Regulation ,chemistry ,Curcumin ,Molecular Medicine ,Tumor necrosis factor alpha - Abstract
Synthesis and anti-inflammatory activity of novel diarylheptanoids [5-hydroxy-1-phenyl-7-(pyridin-3-yl)-heptan-3-ones and 1-phenyl-7-(pyridin-3-yl)hept-4-en-3-ones] as inhibitors of tumor necrosis factor-α (TNF-α) production is described in the present article. The key reactions involve the formation of a β-hydroxyketone by the reaction of substituted 4-phenyl butan-2-ones with pyridine-3-carboxaldehyde in presence of LDA and the subsequent dehydration of the same to obtain the α,β-unsaturated ketones. Compounds 4i, 5b, 5d, and 5g significantly inhibit lipopolysaccharide (LPS)-induced TNF-α production from human peripheral blood mononuclear cells in a dose-dependent manner. Of note, the in vitro TNF-α inhibition potential of 5b and 5d is comparable to that of curcumin (a naturally occurring diarylheptanoid). Most importantly, oral administration of 4i, 5b, 5d, and 5g (each at 100 mg/kg) but not curcumin (at 100 mg/kg) significantly inhibits LPS-induced TNF-α production in BALB/c mice. Collectively, our findings indicate that these compounds may have potential therapeutic implications for TNF-α-mediated auto-immune/inflammatory disorders.
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- 2011
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20. Solar Cells and Mini-Modules Based on 40 Μμm-Thick Epitaxial Si Foils: Towards Conductive Bonding onto Low-Cost Si Powder Sintered Conductive Carriers from the Recycling of Silicon Waste
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H. Sivaramakrishnan Radhakrishnan, K. Van Nieuwenhuysen, J. Govaerts, V. Depauw, T. Bearda, M. Debucquoy, R. Roozeman, J. Heikkinen, M. Schumann, R. Buchwald, H.J. Möller, A. Ciftja, G. Stokkan, E.-J. Øvrelid, A. Stonkus, P. Dubravskij, J. Ulbikas, I. Gordon, J. Szlufcik, J. Poortmans, and A. Ulyashin
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Thin Film Solar Cells and Modules ,Silicon-based Thin Film Solar Cells and Modules ,7. Clean energy - Abstract
32nd European Photovoltaic Solar Energy Conference and Exhibition; 1268-1271, Epitaxial silicon foils (
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- 2016
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21. Formulation and Characterization of Solid Dispersion Prepared by Hot Melt Mixing: A Fast Screening Approach for Polymer Selection
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H. Sivaramakrishnan, Sanket M. Shah, Arno A. Enose, and Priya Dasan
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chemistry.chemical_classification ,Materials science ,Article Subject ,Mixing (process engineering) ,Plasticizer ,lcsh:RS1-441 ,Nanotechnology ,Polymer ,law.invention ,lcsh:Pharmacy and materia medica ,Differential scanning calorimetry ,Optical microscope ,chemistry ,law ,Extrusion ,Dynamic vapor sorption ,Composite material ,Dispersion (chemistry) ,Research Article - Abstract
Solid dispersion is molecular dispersion of drug in a polymer matrix which leads to improved solubility and hence better bioavailability. Solvent evaporation technique was employed to prepare films of different combinations of polymers, plasticizer, and a modal drug sulindac to narrow down on a few polymer-plasticizer-sulindac combinations. The sulindac-polymer-plasticizer combination that was stable with good film forming properties was processed by hot melt mixing, a technique close to hot melt extrusion, to predict its behavior in a hot melt extrusion process. Hot melt mixing is not a substitute to hot melt extrusion but is an aid in predicting the formation of molecularly dispersed form of a given set of drug-polymer-plasticizer combination in a hot melt extrusion process. The formulations were characterized by advanced techniques like optical microscopy, differential scanning calorimetry, hot stage microscopy, dynamic vapor sorption, and X-ray diffraction. Subsequently, the best drug-polymer-plasticizer combination obtained by hot melt mixing was subjected to hot melt extrusion process to validate the usefulness of hot melt mixing as a predictive tool in hot melt extrusion process.
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- 2014
22. Discovery of p1736, a novel antidiabetic compound that improves peripheral insulin sensitivity in mice models
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Vijayalakshmi Ranjith, Somesh Sharma, Sujit Kaur Bhumra, Aditya Kelkar, Nabajyoti Deka, H. Sivaramakrishnan, Jessy Anthony, Shivaprakash Jagalur Mutt, Chandan Wilankar, and Adaikalasamy Rosalind Marita
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medicine.medical_specialty ,Glucose uptake ,medicine.medical_treatment ,lcsh:Medicine ,Aminopyridines ,Type 2 diabetes ,Pharmacology ,Rosiglitazone ,Mice ,Insulin resistance ,Internal medicine ,Hyperinsulinism ,Drug Discovery ,Hyperinsulinemia ,Adipocytes ,Medicine ,Animals ,Hypoglycemic Agents ,lcsh:Science ,Sulfonamides ,Multidisciplinary ,business.industry ,Insulin ,lcsh:R ,medicine.disease ,Metformin ,Mice, Mutant Strains ,Endocrinology ,Glucose ,Diabetes Mellitus, Type 2 ,lcsh:Q ,Thiazolidinediones ,Insulin Resistance ,business ,medicine.drug ,Research Article - Abstract
Insulin resistance is a characteristic feature of Type 2 diabetes. Insulin resistance has also been implicated in the pathogenesis of cardiovascular disease. Currently used thiazolidinedione (TZD) insulin sensitizers although effective, have adverse side effects of weight gain, fluid retention and heart failure. Using fat cell-based phenotypic drug discovery approach we identified P1736, a novel antidiabetic molecule that has completed Phase II clinical trials. The present study evaluated the in vitro and in vivo pharmacological properties of P1736. P1736 is a non-TZD and it did not activate human PPAR(Peroxisome Proliferator Activated Receptor Gamma )receptors. P1736 caused dose dependent increase in glucose uptake (EC50-400 nM) in the insulin resistant 3T3 adipocytes. The compound (10 µM) induced translocation of GLUT-4 (Glucose Transporter type 4) transporters in these adipocytes while metformin (1.0mM) was inactive. In diabetic db/db mice, P1736 (150 mg/kg) was more efficacious than metformin in lowering plasma glucose (35% vs 25%) and triglyceride levels (38% vs 31%). P1736 tested at 5mg/kg, twice daily doses, reduced glucose by 41% and triglycerides by 32%, in db/db mice. These effects were not associated with adverse effects on body weight or liver function. Rosiglitazone (5mg/kg, twice daily) caused 60% and 40 % decreases in glucose and triglyceride levels, respectively. However, rosiglitazone induced 13% weight gain (p
- Published
- 2013
23. Potentiation of anticancer effect of valproic acid, an antiepileptic agent with histone deacetylase inhibitory activity, by the cyclin-dependent kinase inhibitor P276-00 in human non-small-cell lung cancer cell lines
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Maggie Joyce Rathos, H. Sivaramakrishnan, Kalpana Joshi, Umesh Chaudhari, and Nitesh Shirsath
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Pulmonary and Respiratory Medicine ,Cancer Research ,Lung Neoplasms ,Population ,Antineoplastic Agents ,Apoptosis ,Cell Cycle Proteins ,Pharmacology ,Histones ,chemistry.chemical_compound ,Mice ,Cyclin-dependent kinase ,Carcinoma, Non-Small-Cell Lung ,Cell Line, Tumor ,Animals ,Humans ,Propidium iodide ,education ,Protein Kinase Inhibitors ,Tumor Stem Cell Assay ,education.field_of_study ,biology ,Cell growth ,Kinase ,Valproic Acid ,Cell Cycle ,Acetylation ,Flavones ,Xenograft Model Antitumor Assays ,Cyclin-Dependent Kinases ,Histone Deacetylase Inhibitors ,Oncology ,chemistry ,biology.protein ,lipids (amino acids, peptides, and proteins) ,Histone deacetylase ,CDK inhibitor - Abstract
P276-00 is a novel cyclin-dependent kinase (CDK) inhibitor is in Phase II clinical trials. Valproic acid (VPA), an antiepileptic agent has been associated with anticancer activity, through the inhibition of histone deacetylase I. Here we investigate the effect of the combination of VPA and P276-00, in non-small-cell lung cancer (NSCLC) cell lines.Cell growth inhibition was studied using the Propidium iodide (PI) assay. Cell cycle analysis and recovery were detected by flow cytometry. The expression levels of various proteins were detected by western blot. Inhibition of colony formation in H460 was checked in vitro. In vivo efficacy was studied in H460 xenograft model.The combination of P276-00 and VPA showed synergistic effect on p53+ and p53- NSCLC cell lines in antiproliferative assay at both constant and non-constant ratio with marked decrease in colony forming potential. Flow cytometric analysis confirmed a significant time dependent increase in apoptosis with 64% apoptotic population at 96 h compared to VPA (1%) and P276-00 (28%) alone (p0.0001). Incubation of the cells after treatment, in fresh medium without drugs, led to the recovery of cells treated with P276-00 alone but not the cells treated with the combination of both the drugs. The combination treatment up-regulated tumor suppressor proteins like p53, p21 and p27 along with down-regulation of proliferation and survival proteins viz. cyclin D1 and Bcl-2. This was also associated with the upregulation of the pro-apoptotic protein Bax and significant accumulation of hyperacetylated histones in the combination treatment. Interestingly, VPA in combination with P276-00 was much more effective as an antitumor agent than alone, in the H460 xenograft tumor model in SCID mice.This study indicates that the combination of HDAC inhibitor VPA with CDK inhibitor P276-00 is promising novel molecularly targeted therapeutic approach for NSCLC treatment.
- Published
- 2013
24. Harmonic current estimation using mutual information based Independent Component Analysis
- Author
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Raja Krishna Chamarthi, B. Hariharan, S Sriramachandiran, P. Supriya, and H. Sivaramakrishnan
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Harmonic analysis ,Nonlinear system ,Total harmonic distortion ,Harmonic balance ,Engineering ,Electric power system ,Control theory ,business.industry ,Harmonics ,Harmonic ,Electronic engineering ,Power factor ,business - Abstract
Harmonic analysis is an integral part of system planning, design and operation of power systems. Harmonic voltage and current measurements require synchronized measurements which are complicated and more expensive than ordinary measurements. Generally a large number of measurements are required to estimate the harmonic sources using Harmonic State Estimation techniques. In this work, the harmonic current profile in the power system is estimated using minimal information on the power system structure. A blind signal processing technique using Independent Component Analysis based on basic neural network is applied for the detection of harmonic components generated by nonlinear current loads. The harmonic current estimation is carried out on a five bus system and the results obtained in simulation are transported to the embedded platform .NET Micro framework board.
- Published
- 2012
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25. Isocytosine-based inhibitors of xanthine oxidase: design, synthesis, SAR, PK and in vivo efficacy in rat model of hyperuricemia
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Komal Bajaj, Lalit S. Doshi, Rajiv Sharma, Prashant Tannu, Ankita Srivastava, Nitin J. Deshmukh, Manoja K. Brahma, Avani Desai, Anagha Damre, Smriti Khanna, Sandeep Burudkar, Asha Kulkarni-Almeida, Pranay Shah, Usha Ghosh, Chandrika B-Rao, Ashish P. Keche, Amol Dixit, Kumar V.S. Nemmani, Umakant Ashok Bahirat, and H. Sivaramakrishnan
- Subjects
Models, Molecular ,Xanthine Oxidase ,Time Factors ,Clinical Biochemistry ,Pharmaceutical Science ,Administration, Oral ,Hyperuricemia ,Pharmacology ,Biochemistry ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Cytosine ,Structure-Activity Relationship ,Pharmacokinetics ,In vivo ,Drug Discovery ,medicine ,Structure–activity relationship ,Animals ,Isocytosine ,Enzyme Inhibitors ,Rats, Wistar ,Xanthine oxidase ,Molecular Biology ,Dose-Response Relationship, Drug ,Molecular Structure ,Organic Chemistry ,medicine.disease ,In vitro ,Rats ,Disease Models, Animal ,chemistry ,Docking (molecular) ,Drug Design ,Molecular Medicine - Abstract
Structure-activity relationship studies were carried out for lead generation following structure-guided design approach from an isocytosine scaffold identified earlier for xanthine oxidase inhibition. A 470-fold improvement in in vitro IC(50) was obtained in the process. Five most potent compounds with nanomolar IC(50) values were selected for pharmacokinetics and in vivo experiments. The best compound showed good in vivo activity when administered intraperitoneally but was not active by oral route. The results suggest that improvement in oral exposure could improve the in vivo efficacy of this series.
- Published
- 2012
26. Synthesis and biological evaluation of isoxazole, oxazole, and oxadiazole containing heteroaryl analogs of biaryl ureas as DGAT1 inhibitors
- Author
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Nitin J. Deshmukh, H. Sivaramakrishnan, Arno A. Enose, Shaila Srinivasan, Shivaji Kandre, Amol Dixit, Kishorkumar Shivajirao Kadam, Rajiv Sharma, Lalit S. Doshi, M. Mahesh Kumar Reddy, Tandra Guha, Ashok Kumar Gangopadhyay, Ram A. Vishwakarma, Ravindra Dnyandev Jadhav, Amol Gupte, Kumar V.S. Nemmani, Nisha Potdar, and Manoja K. Brahma
- Subjects
Oxadiazole ,Chemistry Techniques, Synthetic ,chemistry.chemical_compound ,Inhibitory Concentration 50 ,Mice ,Structure-Activity Relationship ,In vivo ,Drug Discovery ,Structure–activity relationship ,Organic chemistry ,Animals ,Humans ,Urea ,Diacylglycerol O-Acyltransferase ,Isoxazole ,Solubility ,Enzyme Inhibitors ,Oxazole ,Pharmacology ,chemistry.chemical_classification ,Oxadiazoles ,Organic Chemistry ,Water ,General Medicine ,Isoxazoles ,In vitro ,Enzyme ,chemistry - Abstract
Diacylglycerol acyltransferase, DGAT1, is a promising target enzyme for obesity due to its involvement in the committed step of triglyceride biosynthesis. Amino biphenyl carboxylic acids, exemplified by compound 4, are known potent inhibitors of hDGAT1. However the high cLogP and poor solubility of these biphenyl analogs might tend to limit their development. We have synthesized and evaluated compounds containing 3-phenylisoxazole, 5-phenyloxazole, and 3-phenyl-1,2,4-oxadiazole biaryl units for their hDGAT1 inhibition. Our aim in synthesizing such heterocyclic analogs was to improve the cLogP and solubility of these molecules while retaining hDGAT1 potency. Several compounds within the 3-phenylisoxazole series exhibited potent hDGAT1 inhibition when evaluated using an in vitro enzymatic assay. Certain promising compounds were studied for their potential to reduce triglyceride levels using an in vivo fat tolerance test in mice and were also evaluated for any possible improvement to their solubility. Compound 40a (IC(50) = 64 nM) with an in vivo plasma triglyceride reduction of 90 percent, and a solubility of 0.43 mg/ml at pH 7.4 may serve as a new lead for developing newer anti-obesity agents.
- Published
- 2012
27. Residential task scheduling under dynamic pricing using the multiple knapsack method
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H. Sivaramakrishnan, N. Kumaraguruparan, and Sachin S. Sapatnekar
- Subjects
Mathematical optimization ,Smart grid ,Power demand ,Job shop scheduling ,Computer science ,Knapsack problem ,business.industry ,Dynamic pricing ,Dynamic priority scheduling ,Electricity ,business ,Scheduling (computing) - Abstract
A key component of the smart grid is the ability to enable dynamic residential pricing to incentivize the customer and the overall community to utilize energy more uniformly. However, the complications involved require that automated strategies be provided to the customer to achieve this goal. This paper presents a solution to the problem of optimally scheduling a set of residential appliances under day-ahead variable peak pricing in order to minimize the customer's energy bill (and also, simultaneously spread out energy usage). We map the problem to a well known problem in computer science - the multiple knapsack problem - which enables cheap and efficient solutions to the scheduling problem. Results show that this method is effective in meeting its goals.
- Published
- 2012
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28. ChemInform Abstract: Novel Diarylheptanoids as Inhibitors of TNF-α Production
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H. Sivaramakrishnan and et al. et al.
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Biochemistry ,Chemistry ,General Medicine ,Diarylheptanoids - Published
- 2011
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29. ChemInform Abstract: Novel Palladium-Catalyzed Bicycloannulation of Monoactivated Cyclic Ketones Using a 1,3-Allylic Diacetate and an Enolyzing Catalyst
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Denis Gravel, S Benoît, S. Kumanovic, and H Sivaramakrishnan
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chemistry.chemical_classification ,Allylic rearrangement ,chemistry ,Organic chemistry ,chemistry.chemical_element ,General Medicine ,Bridged compounds ,Catalysis ,Palladium - Published
- 2010
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30. Novel palladium catalyzed bicycloannulation of monoactivated cyclic ketones using a 1,3-allylic diacetate and an enolzying catalyst
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H Sivaramakrishnan, Denis Gravel, S Benoît, and S. Kumanovic
- Subjects
Allylic rearrangement ,Annulation ,Bicyclic molecule ,Chemistry ,Organic Chemistry ,chemistry.chemical_element ,Keto–enol tautomerism ,Biochemistry ,Catalysis ,Potassium carbonate ,chemistry.chemical_compound ,Drug Discovery ,Organic chemistry ,Nonane ,Palladium - Abstract
A novel procedure is reported whereby polysubstituted bicyclo[3.3.1] nonane derivatives are prepared in one step from β-ketoesters providing an adequate enolyzing catalyst is used.
- Published
- 1992
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31. On the palladium catalyzed reaction of methallyl-1,1-diacetate with cyclic β-ketoesters. Intervention of hidden mechanisms
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H Sivaramakrishnan, Denis Gravel, S Benoît, and S. Kumanovic
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chemistry.chemical_classification ,Base (chemistry) ,Bicyclic molecule ,Organic Chemistry ,chemistry.chemical_element ,Methacrolein ,Biochemistry ,Medicinal chemistry ,Catalysis ,chemistry.chemical_compound ,chemistry ,Drug Discovery ,Organic chemistry ,Product formation ,Derivative (chemistry) ,Palladium - Abstract
Palladium(0) catalysis in the title reaction causes the release of methacrolein which competes effectively with the π-allyl species in product formation, a bicycloannulated derivative, when DBU is used as base.
- Published
- 1992
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32. A case of rhino-orbital cerebral mucormycosis with diabetic keto-acidosis
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H, Sivaramakrishnan, S M, Kannan, C, Ravikumar, S, Harishankar, and Santhi, Chellamuthu
- Subjects
Brain Diseases ,Nose Diseases ,Orbital Diseases ,Humans ,Mucormycosis ,Female ,Middle Aged ,Diabetic Ketoacidosis - Abstract
A 60-year-old lady was admitted in the hospital with the complaints of burning sensation during micturition and abdominal pain. She was diagnosed to have moderate hydronephrosis with left lower 1/3rd ureteric calculus for which ureteroscopy and lithotripsy were done. Her pre-operative random blood sugar was normal. On the 7th postoperative day the patient developed diabetic keto-acidosis which was followed by an acute onset of right sided peri-orbital oedema, proptosis and facial pain. Subsequently she developed diminished vision and lower motor neurone type of Ill, IV and VI cranial nerves paralysis on right side, disorientation and minimal left sided hemiparesis. ENT examination revealed black eschar nasal turbinates, nasal septum and palate and a provisional diagnosis of rhino-orbital cerebral mucormycosis was made. Extensive debridement was done for the patient and the specimen culture showed growth of mucor species. Patient was started on intravenous amphotericin-B and she started improving dramatically. This case of rhino-orbital cerebral mucormycosis with diabetic keto-acidois is presented here for its rarity.
- Published
- 2009
33. Comparison of effects of anti-angiogenic agents in the zebrafish efficacy–toxicity model for translational anti-angiogenic drug discovery
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Somesh Sharma, Jayasree Sreenivasan, Nilambari Pawar, H. Sivaramakrishnan, Geetanjali Chimote, and Jyothi Subramanian
- Subjects
Angiogenesis ,Pharmaceutical Science ,Angiogenesis Inhibitors ,Pharmacology ,Metastasis ,Lethal Dose 50 ,Translational Research, Biomedical ,angiogenesis ,Neoplasms ,Toxicity Tests ,Drug Discovery ,medicine ,Animals ,Tumor growth ,therapeutic window ,Zebrafish ,Original Research ,Cell Proliferation ,Therapeutic window ,Drug Design, Development and Therapy ,Neovascularization, Pathologic ,biology ,Drug discovery ,Anti angiogenic ,biology.organism_classification ,medicine.disease ,Receptors, Vascular Endothelial Growth Factor ,zebrafish toxicity assay ,Drug Design ,Models, Animal ,Toxicity ,Cancer research ,VEGFR inhibitors - Abstract
Geetanjali Chimote,1 Jayasree Sreenivasan,1 Nilambari Pawar,1 Jyothi Subramanian,2 Hariharan Sivaramakrishnan,3 Somesh Sharma1,3 1Department of Pharmacology, 2Department of Modeling and Simulation, 3Department of Medicinal Chemistry, Piramal Life Sciences Limited, Mumbai, India Background: Anti-angiogenic therapy in certain cancers has been associated with improved control of tumor growth and metastasis. Development of anti-angiogenic agents has, however, been saddled with higher attrition rate due to suboptimal efficacy, narrow therapeutic windows, or development of organ-specific toxicities. The aim of this study was to evaluate the translational ability of the zebrafish efficacy–toxicity model to stratify anti-angiogenic agents based on efficacy, therapeutic windows, and off-target effects to streamline the compound selection process in anti-angiogenic discovery. Methods: The embryonic model of zebrafish was employed for studying angiogenesis and toxicity. The zebrafish were treated with anti-angiogenic compounds to evaluate their effects on angiogenesis and zebrafish-toxicity parameters. Angiogenesis was measured by scoring the development of subintestinal vessels. Toxicity was evaluated by calculating the median lethal concentration, the lowest observed effect concentration, and gross morphological changes. Results of efficacy and toxicity were used to predict the therapeutic window. Results: In alignment with the clinical outcomes, the zebrafish assays demonstrated that vascular endothelial growth factor receptor (VEGFR) inhibitors are the most potent anti-angiogenic agents, followed by multikinase inhibitors and inhibitors of endothelial cell proliferation. The toxicity assays reported cardiac phenotype in zebrafish treated with VEGFR inhibitors and multikinase inhibitors with VEGFR activity suggestive of cardiotoxic potential of these compounds. Several other pathological features were reported for multikinase inhibitors suggestive of off-target effects. The predicted therapeutic window was translational with the clinical trial outcomes of the anti-angiogenic agents. The zebrafish efficacy–toxicity approach could stratify anti-angiogenic agents based on the mechanism of action and delineate chemical structure-driven biological activity of anti-angiogenic compounds. Conclusion: The zebrafish efficacy–toxicity approach can be used as a predictive model for translational anti-angiogenic drug discovery to streamline compound selection, resulting in safer and efficacious anti-angiogenic agents entering the clinics. Keywords: angiogenesis, therapeutic window, VEGFR inhibitors, zebrafish toxicity assay
- Published
- 2014
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34. A Note on 'A New Algorithm for Symbolic Reliability Analysis'
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H. Sivaramakrishnan and A. Satyanarayana
- Subjects
Theoretical computer science ,Computer science ,Path (graph theory) ,Pattern analysis ,Algorithm design ,Data mining ,Electrical and Electronic Engineering ,Safety, Risk, Reliability and Quality ,Resource management (computing) ,computer.software_genre ,computer ,Reliability (statistics) - Published
- 1977
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35. The Origin of the Maximum in the Adsorption Isotherms of Association Colloids
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Robert D. Vold and N. H. Sivaramakrishnan
- Subjects
Colloid ,Adsorption ,Chemistry ,Inorganic chemistry ,General Engineering ,Physical and Theoretical Chemistry - Published
- 1958
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36. Effect of the excipient concentration on the pharmacokinetics of PM181104, a novel antimicrobial thiazolyl cyclic peptide antibiotic, following intravenous administration to mice
- Author
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Satish Namdeo Sawant, Anagha Damre, Tanaji Deokule, Vijayaphanikumar Yemparala, Venkat Manohar, H. Sivaramakrishnan, Girish B Mahajan, and Kishori Sharan Singh
- Subjects
Tween 80 ,Sociology and Political Science ,medicine.drug_class ,Antibiotics ,Pharmaceutical Science ,Excipient ,PM181104 ,Pharmacology ,Article ,Education ,chemistry.chemical_compound ,Antisolvent precipitation ,Pharmacokinetics ,medicine ,Nanoparticle size ,PEG 400 ,chemistry.chemical_classification ,Chromatography ,Osmotic concentration ,business.industry ,LPN and LVN ,Antimicrobial ,Cyclic peptide ,chemistry ,Particle size ,business ,Law ,medicine.drug - Abstract
Thiazolyl cyclic peptide antibiotics are known for their poor aqueous solubility and unfavorable pharmacokinetics (PK) and hence pose challenging tasks in developing these antibiotics as clinical candidates. In the current paper, we report a possible way to address these challenges with exemplification of our antibiotic PM181104. The approach was to prepare formulations with known excipients, Polysorbate 80 (Tween 80, T-80) and PEG 400 through their varied stiochiometric combination in appropriate ratio to achieve acceptable osmolarity, pH and particle size of the formulation. Two different sets of formulations were prepared with two distinct average particle diameters ranging from 32.8 to 465.4 nm. First, semi-transparent solutions with a particle size of >100 nm were achieved by keeping concentration of PEG 400 constant at 8% (w/v) and decreasing the amounts of T-80. Second, clear colorless solutions with a particle size of, Graphical abstract
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37. A Rapid Algorithm For Reliability Optimisation Of Parallel Redundant Systems
- Author
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A. D. Narasimhalu and H. Sivaramakrishnan
- Subjects
Dynamic programming ,Reliability theory ,Mathematical optimization ,Constraint theory ,Linear programming ,Feasible region ,Optimization methods ,Redundancy (engineering) ,Electrical and Electronic Engineering ,Safety, Risk, Reliability and Quality ,Algorithm ,Mathematics - Abstract
A rapid method is proposed for optimization of reliability of multiconstraint parallel redundant systems. The constraints need not be linear. This method provides good starting values, which are close to the boundary of the feasible region, for the number of redundant units in each subsystem. No proof has been presented to establish the optimality obtained by this method. Yet for examples tried out this method provides optimal or near optimal solutions.
- Published
- 1978
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38. Goodpasture's syndrome (a case report)
- Author
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E S, Johnson, S, Radhakrishnan, M, Chandramohan, and H, Sivaramakrishnan
- Subjects
Adult ,Male ,Nephrotic Syndrome ,Anti-Glomerular Basement Membrane Disease ,Humans - Published
- 1975
39. Correction to 'Redundancy Optimization in General Systems'
- Author
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H. Sivaramakrishnan and A. D. Narasimhalu
- Subjects
Triple modular redundancy ,Computer science ,business.industry ,Redundancy (engineering) ,Telephony ,Electrical and Electronic Engineering ,Safety, Risk, Reliability and Quality ,Dual modular redundancy ,Error detection and correction ,Redundancy optimization ,business ,Algorithm - Published
- 1977
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40. Behavior Change Techniques Involved in Physical Activity Interventions for Children With Chronic Conditions: A Systematic Review.
- Author
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Sivaramakrishnan H, Davis E, Obadimeji L, Valentine J, Wood F, Shetty V, and Finlay-Jones A
- Subjects
- Humans, Child, Chronic Disease psychology, Social Support, Exercise psychology, Behavior Therapy methods
- Abstract
Background: Behavior change techniques (BCTs) have been extensively used in physical activity interventions for children, however, no systematic reviews have synthesized their effects., Purpose: The present review aimed to identify the most promising BCTs used in physical activity interventions associated with (i) increased physical activity behavior and (ii) positive psychosocial outcomes in children with chronic conditions., Methods: A systematic search of 6 databases identified 61 articles as eligible for inclusion. Data, including BCTs, were extracted from these studies and analyzed descriptively. Due to the heterogeneity of interventions, chronic conditions, and outcome measures, a meta-analysis was not conducted., Results: Social support (unspecified), graded tasks, generalization of target behavior, and credible source were the most commonly reported and most promising (i.e., present in 2+ studies evidencing significant effects) BCTs across all studies. These BCTs were found to be especially relevant to improving psychosocial outcomes in the short- and long-term and improving physical activity behaviors in the long-term. Meanwhile, to improve short-term physical activity behaviors, in addition to social support (unspecified), action planning, goal setting (behavior), and problem solving were found to be promising BCTs., Conclusions: The BCTs identified in this review may be relevant to incorporate when planning future interventions to support physical activity and psychosocial outcomes for children with chronic conditions., (© Society of Behavioral Medicine 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
- Published
- 2024
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- View/download PDF
41. Predictors of intentions of adults over 35 years to participate in walking sport programs: A social-ecological mixed-methods approach.
- Author
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Sivaramakrishnan H, Quested E, Cheval B, Thøgersen-Ntoumani C, Gucciardi DF, and Ntoumanis N
- Subjects
- Humans, Adult, Middle Aged, Walking, Exercise, Attitude, Intention, Sports psychology
- Abstract
There is a growing need to identify acceptable and feasible opportunities to engage adults over 35 years in physical activity. Walking sports may be a potential means to engage adults in sport; however, there is limited evidence regarding appeal and feasibility to support its implementation and delivery. Using a two-step mixed-methods approach, we aimed (1) to quantitively identify significant predictors of intentions of adults over 35 years to participate in walking sports and (2) to understand why and how these identified predictors may be contextually relevant to the target group. In phase one, 282 adults over 35 years (M
age = 46.08, SD = 9.75) without prior experience of walking sports completed an online questionnaire assessing personal, psychosocial, program-related, and environmental predictors, and intentions to participate in walking sports. Hierarchical multiple linear regressions showed that perceived health status, attitudes, subjective norms, and distance of venue were significant predictors of intentions. In phase two, interviews with a subset of 17 participants indicated that, when implementing walking sport programs, program labeling, fear of the unknown, and individual differences in the appeal of walking sport warrant consideration. Together, these findings offer insight into the complex interplay of personal, psychosocial, program-related, and environmental predictors of adults' intentions to participate in walking sports. Addressing these elements of a walking sport program would make such programs more appealing to potential participants, and ultimately, more feasible and sustainable to conduct in the long run., (© 2023 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)- Published
- 2023
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42. "More than just a walk in the park": A multi-stakeholder qualitative exploration of community-based walking sport programmes for middle-aged and older adults.
- Author
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Sivaramakrishnan H, Phoenix C, Quested E, Thogersen-Ntoumani C, Gucciardi DF, Cheval B, and Ntoumanis N
- Abstract
In spite of the large-scale growth of walking sport (WS) programmes globally, limited research has explored the experiences of the key stakeholders involved in such programmes (i.e. decision-makers, facilitators, and players). We aimed to explore stakeholder experiences of community-based WS programmes to better understand the appeal of such sport options for middle-aged and older adults, and propose tentative recommendations for the feasibility and sustainability of these types of programmes. We conducted semi-structured interviews with 21 stakeholders who were involved with WS programmes in Australia as decision-makers, facilitators, and/or players. Data were analysed with reflexive thematic analysis. Four key themes pertaining to the WS experience were identified - 'a renewed lease of life', 'navigating ageing stereotypes', 'tension between organisational demands and players' needs', and 'WS facilitators as catalysts of success'. Specifically, we found that WS participation enabled a positive ageing discourse for middle-aged and older adults. WS players had to negotiate stereotypes that, at times, were perceived as participation barriers. We also noted some tensions between the demands of sport organisations and the needs of middle-aged and older adults regarding sport participation. Finally, we also noted the importance of the facilitators' role in increasing accessibility of, and long-term participation in, such programmes. We suggest that to offer feasible and sustainable community-based WS programmes across Australia, incompatibilities across various stakeholders' perspectives need to be addressed., Competing Interests: No potential conflict of interest was reported by the author(S)., (© 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)
- Published
- 2023
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43. A systematic review examining socioeconomic factors in trials of interventions for men that report weight as an outcome.
- Author
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McDonald MD, Hunt K, Sivaramakrishnan H, Moullin J, Avenell A, Kerr DA, Birch JM, Ntoumanis N, and Quested E
- Subjects
- Humans, Male, Socioeconomic Factors, Nutrition Therapy
- Abstract
Weight management interventions designed specifically for men have become more common, but the extent to which socioeconomic factors are considered in trials of these interventions is unclear. We synthesized study characteristics, methods, and reporting of interventions with a behavioral component for men that report weight as an outcome, to establish the extent to which socioeconomic factors are considered during intervention design, conduct, and reporting. A comprehensive search was conducted on Medline, Embase, PsycINFO, and CENTRAL for studies published from January 2000 to July 2021. Thirty-six trials were included. Educational attainment (n = 24) was the most frequently reported socioeconomic characteristic, followed by working status (n = 14) and area level deprivation (n = 12). Seven studies did not report any socioeconomic characteristics. Most studies (n = 20) did not mention the socioeconomic profile of their samples in relation to study strengths or limitations. Few (n = 4) consulted with men from lower socioeconomic groups during intervention design. One study examined potential differential intervention effects across socioeconomic groups, with most not powered to do so. Recent feasibility trials (n = 3) targeting specific socioeconomic groups suggest a potential nascent towards a greater consideration of factors related to equity. To best inform public health policy related to health inequalities, greater consideration of socioeconomic factors is required in trials of men's weight management interventions., (© 2022 The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of World Obesity Federation.)
- Published
- 2022
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44. Local Enhancement of Dopant Diffusion from Polycrystalline Silicon Passivating Contacts.
- Author
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Fırat M, Wouters L, Lagrain P, Haase F, Polzin JI, Chaudhary A, Nogay G, Desrues T, Krügener J, Peibst R, Tous L, Sivaramakrishnan Radhakrishnan H, and Poortmans J
- Abstract
Passivating contacts consisting of heavily doped polycrystalline silicon (poly-Si) and ultrathin interfacial silicon oxide (SiO
x ) films enable the fabrication of high-efficiency Si solar cells. The electrical properties and working mechanism of such poly-Si passivating contacts depend on the distribution of dopants at their interface with the underlying Si substrate of solar cells. Therefore, this distribution, particularly in the vicinity of pinholes in the SiOx film, is investigated in this work. Technology computer-aided design (TCAD) simulations were performed to study the diffusion of dopants, both phosphorus (P) and boron (B), from the poly-Si film into the Si substrate during the annealing process typically applied to poly-Si passivating contacts. The simulated 2D doping profiles indicate enhanced diffusion under pinholes, yielding deeper semicircular regions of increased doping compared to regions far removed from the pinholes. Such regions with locally enhanced doping were also experimentally demonstrated using high-resolution (5-10 nm/pixel) scanning spreading resistance microscopy (SSRM) for the first time. The SSRM measurements were performed on a variety of poly-Si passivating contacts, fabricated using different approaches by multiple research institutes, and the regions of doping enhancement were detected on samples where the presence of pinholes had been reported in the related literature. These findings can contribute to a better understanding, more accurate modeling, and optimization of poly-Si passivating contacts, which are increasingly being introduced in the mass production of Si solar cells.- Published
- 2022
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45. Evolution of physical activity habits after a context change: The case of COVID-19 lockdown.
- Author
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Maltagliati S, Rebar A, Fessler L, Forestier C, Sarrazin P, Chalabaev A, Sander D, Sivaramakrishnan H, Orsholits D, Boisgontier MP, Ntoumanis N, Gardner B, and Cheval B
- Subjects
- Communicable Disease Control, Exercise, Habits, Humans, SARS-CoV-2, COVID-19
- Abstract
Objective: Habits, defined as well-learned associations between cues and behaviours, are essential for health-related behaviours, including physical activity (PA). Despite the sensitivity of habits to context changes, little remains known about the influence of a context change on the interplay between PA habits and behaviours. We investigated the evolution of PA habits amidst the spring COVID-19 lockdown, a major context change. Moreover, we examined the association of PA behaviours and autonomous motivation with this evolution., Design: Three-wave observational longitudinal design., Methods: PA habits, behaviours, and autonomous motivation were collected through online surveys in 283 French and Swiss participants. Variables were self-reported with reference to three time-points: before-, mid-, and end-lockdown., Results: Mixed effect modelling revealed a decrease in PA habits from before- to mid-lockdown, especially among individuals with strong before-lockdown habits. Path analysis showed that before-lockdown PA habits were not associated with mid-lockdown PA behaviours (β = -.02, p = .837), while mid-lockdown PA habits were positively related to end-lockdown PA behaviours (β = .23, p = .021). Autonomous motivation was directly associated with PA habits (ps < .001) and withto before- and mid-lockdown PA behaviours (ps < .001) (but not with end-lockdown PA behaviours) and did not moderate the relations between PA behaviours and habits (ps > .072)., Conclusion: PA habits were altered, and their influence on PA behaviours was impeded during the COVID-19 lockdown. Engagement in PA behaviours and autonomous motivation helped in counteracting PA habits disruption., (© 2021 The British Psychological Society.)
- Published
- 2021
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46. Relationships between changes in self-reported physical activity, sedentary behaviour and health during the coronavirus (COVID-19) pandemic in France and Switzerland.
- Author
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Cheval B, Sivaramakrishnan H, Maltagliati S, Fessler L, Forestier C, Sarrazin P, Orsholits D, Chalabaev A, Sander D, Ntoumanis N, and Boisgontier MP
- Subjects
- Adult, Anxiety, Female, France, Humans, Linear Models, Longitudinal Studies, Male, Middle Aged, Pandemics, Self Report, Switzerland, Young Adult, COVID-19, Exercise, Mental Health, Sedentary Behavior
- Abstract
To assess whether changes in physical activity and sedentary behaviour during the COVID-19 lockdown are associated with changes in mental and physical health. Observational longitudinal study. Participants living in France or Switzerland responded to online questionnaires measuring physical activity, physical and mental health, anxiety, and depressive symptoms. Paired sample t-tests were used to assess differences in physical activity and sedentary behaviour before and during lockdown. Multiple linear regressions were used to investigate associations between changes in physical activity and changes in mental and physical health during lockdown. 267 (wave1) and 110 participants (wave2; 2 weeks later) were recruited. Lockdown resulted in higher time spent in walking and moderate physical activity (~10min/day) and in sedentary behaviour (~75min/day), compared to pre COVID-19. Increased physical activity during leisure time from week 2 to week 4 of lockdown was associated with improved physical health (β=.24, p =.002). Additionally, an increase in sedentary behaviour during leisure time was associated with poorer physical health (β=-.35, p =.002), mental health (β=-.25, p =.003), and subjective vitality (β=-.30, p =.004). Ensuring sufficient levels of physical activity and reducing sedentary time can play a vital role in helping people to cope with a major stressful event, such as the COVID-19 pandemic.
- Published
- 2021
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47. Chlorotrifluoroethylidenes: an efficient and convenient approach to their synthesis.
- Author
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Upare AA, Gadekar PK, Jadhav K, Sivaramakrishnan H, and Roopan SM
- Abstract
A convenient one step synthesis of chlorotrifluoroalkyl olefins starting from aldehydes was developed. The stable reagent 2-((1-chloro-2,2,2-trifluoroethyl)sulfonyl)benzothiazole was prepared from readily available benzothiazole-2-thiol and halothane. This method comprises using stable 2-((1-chloro-2,2,2-trifluoroethyl)sulfonyl)benzothiazole according to the Julia procedure and presents new opportunities for the synthesis of trifluoroalkylidene derivatives., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2020
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48. Design, synthesis and biological evaluation of (E)-5-styryl-1,2,4-oxadiazoles as anti-tubercular agents.
- Author
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Atmaram Upare A, Gadekar PK, Sivaramakrishnan H, Naik N, Khedkar VM, Sarkar D, Choudhari A, and Mohana Roopan S
- Subjects
- Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Dose-Response Relationship, Drug, Microbial Sensitivity Tests, Molecular Structure, Oxadiazoles chemical synthesis, Oxadiazoles chemistry, Structure-Activity Relationship, Antitubercular Agents pharmacology, Drug Design, Mycobacterium tuberculosis drug effects, Oxadiazoles pharmacology
- Abstract
Cinnamic acid and its derivatives are known for anti-tubercular activity. The present study reports the synthesis of cinnamic acid derivatives via bioisosteric replacement of terminal carboxylic acid with "oxadiazole". A series of cinnamic acid derivatives (styryl oxadiazoles) were designed and synthesized in good yields by reaction of substituted cinnamic acids (2, 15a-15s) with amidoximes. The synthesized styryl oxadiazoles were evaluated in vitro for anti-tubercular activity against Mycobacterium tuberculosis (Mtb) H37Ra strain. The structure-activity relationship (SAR) study has identified several compounds with mixed anti-tubercular profiles. The compound 32 displayed potent anti-tubercular activity (IC
50 = 0.045 µg/mL). Molecular docking studies on mycobacterial enoyl-ACP reductase enzyme corroborated well with the experimental findings providing a platform for structure based hit-to-lead development., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2019
- Full Text
- View/download PDF
49. In vitro antibacterial activities of a thiazolyl peptide antibiotic PM2409.
- Author
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Pari K, Mahajan GB, Yemparala V, Kshirsagar R, Parab R, Shanbhag P, Thomas B, Manisha M, Manohar V, and Sivaramakrishnan H
- Subjects
- Anti-Bacterial Agents chemistry, Bacteria drug effects, Microbial Sensitivity Tests, Peptides, Cyclic chemistry, Thiazoles chemistry, Anti-Bacterial Agents pharmacology, Peptides, Cyclic pharmacology, Thiazoles pharmacology
- Published
- 2015
- Full Text
- View/download PDF
50. Comparison of effects of anti-angiogenic agents in the zebrafish efficacy-toxicity model for translational anti-angiogenic drug discovery.
- Author
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Chimote G, Sreenivasan J, Pawar N, Subramanian J, Sivaramakrishnan H, and Sharma S
- Subjects
- Angiogenesis Inhibitors administration & dosage, Angiogenesis Inhibitors toxicity, Animals, Cell Proliferation drug effects, Drug Design, Lethal Dose 50, Models, Animal, Neoplasms blood supply, Neoplasms drug therapy, Neovascularization, Pathologic pathology, Toxicity Tests methods, Zebrafish embryology, Angiogenesis Inhibitors pharmacology, Neovascularization, Pathologic drug therapy, Receptors, Vascular Endothelial Growth Factor antagonists & inhibitors, Translational Research, Biomedical methods
- Abstract
Background: Anti-angiogenic therapy in certain cancers has been associated with improved control of tumor growth and metastasis. Development of anti-angiogenic agents has, however, been saddled with higher attrition rate due to suboptimal efficacy, narrow therapeutic windows, or development of organ-specific toxicities. The aim of this study was to evaluate the translational ability of the zebrafish efficacy-toxicity model to stratify anti-angiogenic agents based on efficacy, therapeutic windows, and off-target effects to streamline the compound selection process in anti-angiogenic discovery., Methods: The embryonic model of zebrafish was employed for studying angiogenesis and toxicity. The zebrafish were treated with anti-angiogenic compounds to evaluate their effects on angiogenesis and zebrafish-toxicity parameters. Angiogenesis was measured by scoring the development of subintestinal vessels. Toxicity was evaluated by calculating the median lethal concentration, the lowest observed effect concentration, and gross morphological changes. Results of efficacy and toxicity were used to predict the therapeutic window., Results: In alignment with the clinical outcomes, the zebrafish assays demonstrated that vascular endothelial growth factor receptor (VEGFR) inhibitors are the most potent anti-angiogenic agents, followed by multikinase inhibitors and inhibitors of endothelial cell proliferation. The toxicity assays reported cardiac phenotype in zebrafish treated with VEGFR inhibitors and multikinase inhibitors with VEGFR activity suggestive of cardiotoxic potential of these compounds. Several other pathological features were reported for multikinase inhibitors suggestive of off-target effects. The predicted therapeutic window was translational with the clinical trial outcomes of the anti-angiogenic agents. The zebrafish efficacy-toxicity approach could stratify anti-angiogenic agents based on the mechanism of action and delineate chemical structure-driven biological activity of anti-angiogenic compounds., Conclusion: The zebrafish efficacy-toxicity approach can be used as a predictive model for translational anti-angiogenic drug discovery to streamline compound selection, resulting in safer and efficacious anti-angiogenic agents entering the clinics.
- Published
- 2014
- Full Text
- View/download PDF
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