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Investigation of fullerene cluster growth mechanisms by carbon atom addition using classical molecular dynamics. J Chem Phys 2023; 159:154303. [PMID: 37861124 DOI: 10.1063/5.0166116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/28/2023] [Indexed: 10/21/2023] Open
Abstract
The mechanisms of carbon sticking reactions to C36 and C-C80 fullerenes were investigated with molecular dynamics simulations (MD) using the Second-generation Reactive Empirical Bond Order (SREBO) and Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) potentials that were specifically optimized for carbon-carbon interactions. Results showed the existence of three possible sticking configurations where the projectile atom can stick either to one, two or three atoms of the target fullerene. They also showed that although the two potentials give similar magnitudes for the sticking cross-sections, they yield fairly different results as far as sticking mechanisms and configurations at thermal collision-energies, i.e., in the range 0.05-0.5 eV, are concerned. While AIREBO, that takes into account the long-range Lennard-Jones interaction, essentially results in a surface-sticking configuration with a single atom of the target fullerene, SREBO potential yields both surface- and two neighbors-sticking (2N-sticking) configurations. The fullerene structure is preserved in the last configuration while it can be recovered by a 2000 K annealing in the former configuration. Results obtained with SREBO eventually showed larger sticking probabilities for C36 as compared with C80. In spite of this, the sticking cross-sections obtained for C80 are similar to or even larger than those obtained for C36 due to the larger size of C80 that compensates for its smaller sticking probabilities.
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A Doctor in the House, An Ethical Consideration on Treating Their Family Members: A Mixed-Method Study. Cureus 2023; 15:e44230. [PMID: 37772215 PMCID: PMC10523028 DOI: 10.7759/cureus.44230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2023] [Indexed: 09/30/2023] Open
Abstract
BACKGROUND The ethical dilemma of doctors treating their own family members has long been a contentious issue in the field of medicine. Despite these dilemmas, doctors may feel compelled to become involved in the care of family members and reluctant to set standards for themselves. Therefore, this study aimed to assess the experience of doctors in the treatment of their families in Perambalur District, Tamil Nadu, India. METHODOLOGY A mixed-method study was conducted among the doctors in Perambalur District, Tamil Nadu, India from December 2021 to October 2022. A semi-structured questionnaire was used to assess the socio-demographic details and the experience of doctors in treating their family members, followed by a focused group discussion (FGD). Data were analyzed using SPSS version 16 (SPSS Inc., Chicago). A scatter plot was created to visualize the relationship between age, experience of doctors, and confidence level with the frequency of treating family members. A chi-square test was performed to find any associations, and a p-value <0.05 was considered significant. For qualitative data, a fish herringbone model was constructed. RESULTS A total of 72 doctors participated in the study. The study found that almost all the doctors (100%) received medical requests from family members, the median number of requests received in a year was 6.5 with an interquartile range of 4-8 and three-quarters (66.6%) of them accepted the requests and treated them. However, concerns about maintaining objectivity, emotional attachment, and loss of confidentiality were cited as primary reasons for not accepting all requests. The study also found a positive relationship between age, years of experience, and the frequency of treating family members. The FGD highlighted challenges related to potential risks in managing complex cases, emotional involvement impacting decision-making, conflicts of interest, and pressures from family members and societal norms. CONCLUSION In the present study, almost all the doctors received requests from their family members in the last year, and more than three-fourths of the doctors treated their family members. One-fourth of the doctors rejected requests from family members due to concerns about the potential loss of objectivity and the risk of misdiagnosing symptoms caused by emotional attachments. This study sheds light on the complexities and ethical considerations doctors face when treating family members. It emphasizes the need for medical ethics education in the curriculum to guide future doctors in making ethical decisions in such situations. Implementing clear-cut medical ethics guidelines in India would be instrumental in addressing these issues and ensuring ethical practices in the medical field.
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Evaluating the Impact of Summer Drought on Vegetation Growth Using Space-Based Solar-Induced Chlorophyll Fluorescence Across Extensive Spatial Measures. BIG DATA 2022; 10:230-245. [PMID: 33983846 DOI: 10.1089/big.2020.0350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Drought is the primary and dominant natural cause of stress on vegetation, and thus, it needs our full attention. Current understanding of drought across extensive spatial measures, around the world, is considerably limited. As case studies to evaluate the feasibility of utilizing space-based solar-induced chlorophyll fluorescence (SIF) across extensive spatial measures, here, we have used data from 2007 to 2017 in Heilongjiang and Jiangsu provinces of China. The onset of the 2015 drought was accompanied by a substantial response of SIF from vegetation in both the provinces; these data were associated with changes in soil moisture, standardized precipitation evapotranspiration index, and emissivity. Our findings suggest that SIF can effectively provide the spatial and temporal progress of drought, as inferred through substantial associations with SIF normalized by absorbed photosynthetically active radiation (related to ΦF) and by photosynthetically active radiation (SIFpar). For the depiction of onset to drought, SIF, ΦF, and SIFpar provide a significant association and a quicker response than the leaf area index and the normalized difference vegetation index. Furthermore, we found that the correlation between gross primary productivity and SIF is highly substantial in both Heilongjiang (R2 = 0.85, p < 0.001) and Jiangsu (R2 = 0.75, p < 0.001) during the drought period. Our results indicate that continuing evaluation from space-based SIF can indeed provide an understanding of the seasonal differences in vegetation for evaluating the impact of drought across extensive spatial measures.
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Case series of invasive lung infections by Aspergillus species and zygomycosis among post COVID-19 and post-transplant individuals. J Family Med Prim Care 2022; 11:7469-7475. [PMID: 36993027 PMCID: PMC10041196 DOI: 10.4103/jfmpc.jfmpc_1066_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 12/24/2022] Open
Abstract
Airborne pathogens like Aspergillus bring the lungs in the frontline for defense. Pulmonary diseases caused by Aspergillus species are broadly classified as aspergilloma, chronic necrotizing pulmonary aspergillosis, invasive pulmonary aspergillosis (IPA), and bronchopulmonary aspergillosis. Intensive care unit (ICU) admission is required for a large number of patients associated with IPA. It is not yet known whether patients with coronavirus disease 2019 (COVID-19) are at a similar risk for IPA as for influenza. However, usage of steroids plays a leading role in COVID-19. The family Mucoraceae includes filamentous fungi of the order Mucorales, causing a rare opportunistic fungal infection known as mucormycosis. The most commonly reported clinical presentations of mucormycosis are rhinocerebral, pulmonary, cutaneous, gastrointestinal, disseminated, and others. Here, we report a case series of invasive pulmonary infection by various fungi like Aspergillus niger, Aspergillus fumigatus, Rhizopus oryzae, and Mucor species. Specific diagnosis was made based on microscopy, histology, culture, lactophenol cotton blue (LPCB) mount, and chest radiography and computed tomography (CT). To conclude, opportunistic fungal infections like those due to Aspergillus species and mucormycosis are most commonly associated with hematological malignancies, neutropenia, transplant patients, and diabetes. Therefore, early diagnosis by direct microscopy, surgical interventions, and effective antifungal treatment form the ideal management for invasive fungal infections like aspergillosis and mucormycosis, instead of waiting for the culture reports.
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How much can we rely on a scrambled COVID-19 vaccine? It is not the only way out! MEDICAL JOURNAL OF DR. D.Y. PATIL VIDYAPEETH 2022. [DOI: 10.4103/mjdrdypu.mjdrdypu_591_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Notice of Retraction: Adaptive Decentralized Tracking Control for Nonlinear Large-Scale Systems. INT J UNCERTAIN FUZZ 2021. [DOI: 10.1142/s0218488521930016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This article has been retracted at the request of the first and corresponding author, Dr. Karthik Chandran. The author has alerted the Editor-in-Chief of IJUFKS the reasons for the retraction: The proposed system was modelled with the incorrect data set. The system response has become incorrect because of this incorrect data set. Two percent of the information (mathematical assumptions) was taken from one paper without proper citation of the source.
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Statistical abundance and stability of carbon nanostructures by combined condensation-annealing molecular dynamics simulations. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Adaptive Decentralized Tracking Control for Nonlinear Large-Scale Systems. INT J UNCERTAIN FUZZ 2020. [DOI: 10.1142/s0218488520400176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Decentralized Model Reference Adaptive Control problems are investigated for a class of linear time-invariant two time-scale model, having fast and slow dynamics and unmatched interconnections. Design of full state feedback controller is a critical task to the system having interrelated dynamics and nonlinear interconnections of time varying lags, however, can be addressed by singular perturbation procedures and time scale modeling. In this research, full order observer-based state feedback control is designed to two-time scale system to ensure the stability of the closed loop system. Then, decentralized model reference adaptive controller with the novel reference model is designed to individual subsystems. It is found that the proposed design enforces the system states to track the reference state asymptotically. To investigate the proposed design, an example of drying process is considered. Simulation results are analyzed to confirm the efficacy of the proposed control scheme.
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An ontology enabled internet of things framework in intelligent agriculture for preventing post-harvest losses. COMPLEX INTELL SYST 2020. [DOI: 10.1007/s40747-020-00183-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AbstractConstituting the agriculture solid substance manufacture, the post-harvest sector processing schema is direct to preventing reduce the losses in intelligent agriculture. Many processing schemata will be preventing post-harvest losses on the agriculture solid substance manufacture, especially sekai-ichi apple is the regularly used fruit also used to make active in human-related activities of the sensory and control function consisting of an agricultural industry. Sekai-ichi apple is being a definite number of diseases induce, but it is to the highest degree of wastage involving in the Post-Harvest process. Especially sekai-ichi apple count loss is an unsafe many time because it not critically post-harvest. Regardless of consideration, the existing hierarchical model specified post-harvest losses prevention research has deficiencies to precise and quick detection of wastage for ensuring healthy separation of agriculture surroundings. This paper suggests a “Hierarchical Model within Ontology Enabled IoT” for distinguishable healthy separation of sekai-ichi apple by using Boosted Continuous Non-spatial whole Attribute Extraction (BCNAE). Sekai-ichi apple count loss is always safe on critically post-harvest. Proposed Post-Harvest hierarchical model specified post-harvest losses prevention and deficiencies to precise and quick detection of wastage for ensuring healthy separation of agriculture surroundings. In these suggestions, the separation cognitive operation takes the three levels of processing schemes such as lower level, middle level, and higher level. Firstly, the lower level is express agreements with the dynamic functioning for maintaining the definite number of manual induces. This lower level showing an absorption with the activity of manual separation by the human reliability determination. Secondly, the middle level is an express arrangement with the dynamic functioning for reducing the overfitting and accommodate to fitting the right shape deliberation. Middle level is establishing being generalized by concentrating the time-varying features in the occurrence of a change for the worse identification. Finally, the upper level is express for features refining with the help of the function of sekai-ichi apple image segmentation connection. This interpretability process helps to make the proven position of a prominent classification in a particular fruit on the agriculture solid substance. These three processing flow constructs the ontology structure with manually collected sekai-ichi apple images from a 3D sensor. The observational consequences express that the proposed BCNAE framework recognizes a detection performance carrying out with an optimized—separation ratio for time-variant of the separation process.
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Chromoblastomycosis caused by Cladophialophora carrionii in a skin graft recipient. Med J Armed Forces India 2016; 72:389-392. [PMID: 27843190 DOI: 10.1016/j.mjafi.2015.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 08/16/2015] [Indexed: 11/16/2022] Open
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Factors preventing early intervention in knee osteoarthritis—focus group study findings. Physiotherapy 2015. [DOI: 10.1016/j.physio.2015.03.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Growth and characterisation of a new polymorph of barium maleate: a metal organic framework. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 137:778-784. [PMID: 25265523 DOI: 10.1016/j.saa.2014.08.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 08/06/2014] [Accepted: 08/24/2014] [Indexed: 06/03/2023]
Abstract
A new polymorph of barium maleate (BM) with chemical formula C24H14O24Ba5⋅7H2O is grown by modified gel method. Transparent plate like crystals of dimensions 9×4×1 mm(3) were obtained. Single crystal X-ray Diffraction analysis was done to determine the structure and the crystal belongs to triclinic system, P-1 space group with cell dimensions a=7.2929(3) Å, b=10.5454(4) Å, c=14.2837(6) Å, α=102.0350(10)°, β=99.1580(10)°, γ=102.9170(10)°. Hydrogen bonding stabilises the two dimensional polymeric crystal structure. Fourier Transform Infrared spectroscopic method was utilised for the analysis of various functional groups present in the complex. Elemental analysis confirmed the stoichiometry of the complex. Thermal properties of the crystal were studied by TGA/DTA. The material melts at 368°C. The optical transparency of the crystal was studied using UV-Visible absorption spectra. The optical band gap is found to be 3.35 eV.
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Seroprevalence of TORCH infections in antenatal and HIV positive patient populations. Med J Armed Forces India 2015; 71:135-8. [PMID: 25859075 DOI: 10.1016/j.mjafi.2014.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 12/07/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The TORCH (Toxoplasma gondii, Rubella, Cytomegalovirus (CMV) and the Herpes Simplex Virus) cause range of diseases in pregnant women and HIV patients and lead to adverse fetal outcomes when not treated on time, in HIV positive can cause life threating infections. There is inadequate data available of these infections in India. METHODS A retrospective study was undertaken to determine the seroprevalence of the TORCH infections in antenatal and HIV/AIDS patients at a tertiary care centre. The laboratory data pertaining to the period Jan 2012-May 2014 was analyzed. The study population involved 162 antenatal cases and 729 HIV/AIDS patients under review at an ART centre. Laboratory testing was done for the presence of IgM and IgG antibodies against the TORCH infections by ELISA method. RESULTS Among the antenatal cases, 30 (18.52%) samples were found to be seropositive for Toxoplasma IgM, CMV IgM antibodies were found in 47 (29.01%) samples, HSV IgM antibodies were found in 12 (7.40%) samples, Rubella IgM antibodies were found in 13 (8.02%) samples, indicating recent infection. Among the HIV/AIDS cases, indicative of recent or current infection, 160 (21.94%) samples were positive for Toxoplasma IgM, CMV IgM was found in 99 (13.58%), HSV IgM antibodies were found in 98 (13.44%) and Rubella IgM in 47 (6.44%). CONCLUSIONS The study showed a high seroprevalence of the infections caused by the TORCH complex amongst pregnant women and HIV/AIDS patients despite improved hygiene conditions and health awareness. Maximum seroprevalence for CMV was observed followed by Rubella and HSV infection.
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A case of Aspergillus nidulans causing white granule mycetoma. Med J Armed Forces India 2015; 72:88-90. [PMID: 26900232 DOI: 10.1016/j.mjafi.2014.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 11/06/2014] [Indexed: 10/24/2022] Open
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Growth and characterisation of crystals of a new organic complex of thiourea with quinine sulphate dihydrate: an NLO material. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 120:517-523. [PMID: 24216117 DOI: 10.1016/j.saa.2013.09.090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/14/2013] [Accepted: 09/26/2013] [Indexed: 06/02/2023]
Abstract
An organic complex of thiourea and quinine sulphate dihydrate (TQS) has been grown for the first time by gel method. The structure determination was done by the single crystal XRD technique. The crystal belongs to monoclinic system, P21 space group with cell dimensions a=6.228 (3) Å, b=20.4051 (4) Å, c=11.0600 (6) Å, β=101.9811(2)°. The crystal structure is stabilized by the hydrogen bonding. The functional groups present in the complex were analysed by the Fourier Transform Infrared spectroscopic method. The stoichiometry of the complex was confirmed by the elemental analysis. Thermal properties of the complex were determined by TGA and DTA methods and the complex melts at 222.53°C. The optical transparency of the crystal was studied using UV-Visible absorption spectra. The optical band gap is found to be 2.5 eV. The SHG conversion efficiency of TQS was investigated using Kurtz and Perry method and found to be higher than that of the reference material, potassium dihydrogen phosphate (KDP).
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Crystal structure, spectral, thermal and dielectric studies of a new zinc benzoate single crystal. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 97:1002-1006. [PMID: 22925975 DOI: 10.1016/j.saa.2012.07.107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 07/21/2012] [Accepted: 07/26/2012] [Indexed: 06/01/2023]
Abstract
Single crystals of zinc benzoate with a novel structure were grown in gel media. Sodium metasilicate of gel density 1.04 g/cc at pH 6 was employed to yield transparent single crystals. The crystal structure of the compound was ascertained by single crystal X-ray diffractometry. It was noted that the crystal belongs to monoclinic system with space group P2(1)/c with unit cell parameters a=10.669(1)Å, b=12.995(5)Å, c=19.119(3)Å, and β=94.926(3)°. The crystal was seen to possess a linear polymeric structure along b-axis; with no presence of coordinated or lattice water. CHN analysis established the stoichiometric composition of the crystal. The existence of functional groups present in the single crystal system was confirmed by FT-IR studies. The thermal characteristic of the sample was analysed by TGA-DTA techniques, and the sample was found to be thermally stable up to 280°C. The kinetic and thermodynamic parameters were also determined. UV-Vis spectroscopy corroborated the transparency of the crystal and revealed the optical band gap to be 4 eV. Dielectric studies showed decrease in the dielectric constant of the sample with increase in frequency.
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Newer Emerging Pathogens of Ocular Non-Sporulating Molds (NSM) Identified by Polymerase Chain Reaction (PCR)-Based DNA Sequencing Technique Targeting Internal Transcribed Spacer (ITS) Region. Curr Eye Res 2009; 33:139-47. [DOI: 10.1080/02713680701864780] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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A linear time algorithm for finding an optimal degree-bounded subtree of an edge-weighted tree. INFORM PROCESS LETT 2009. [DOI: 10.1016/j.ipl.2009.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Topological polar surface area (TPSA), which makes use of functional group contributions based on a large database of structures, is a convenient measure of the polar surface area that avoids the need to calculate ligand 3D structure or to decide which is the relevant biological conformation or conformations. We demonstrate the utility of TPSA in 2D-QSAR for 14 sets of diverse pharmacological activity data. Even though a large pool of reports showing the importance of the classic 2D descriptors such as calculated logP (ClogP) and calculated molar refractivity (CMR) exists in the 2D-QSAR literature, this is the first report to demonstrate the value of TPSA as a relevant descriptor applicable to a large, structurally and pharmacologically diverse set of classes of compounds. We also address the limitations of applicability of this descriptor for 2D-QSAR analysis. We observed a negative correlation of TPSA with activity data for anticancer alkaloids, MT1 and MT2 agonists, MAO-B and tumor necrosis factor-alpha inhibitors and a positive correlation with inhibitory activity data for telomerase, PDE-5, GSK-3, DNA-PK, aromatase, malaria, trypanosomatids and CB2 agonists.
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Quantitative structure–activity relationship analysis of 2,3-diaryl indoles as selective cyclooxygenase-2 inhibitors. J Enzyme Inhib Med Chem 2008; 20:455-61. [PMID: 16335053 DOI: 10.1080/14756360500277251] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Quantitative structure-activity relationship (QSAR) studies have been performed on a combined series of 2-sulfonylphenyl-3-phenyl-indoles and 2-phenyl-3-sulfonylphenyl-indoles with a common 2,3 vicinal diaryl indole scaffold, recently reported as selective COX-2 inhibitors. This study is aimed to throw light on this, special class of diaryl heterocyclic family of selective COX-2 inhibitors. A preliminary Fujita-Ban analysis on 32 compounds provided valuable insights about the role of different substituents R1 and R2 around the 2,3 vicinal diaryl rings and R3, at position-5 of the central indole moiety in explaining their in vitro COX-2 inhibitory activity. The contribution of R1, R2, R3 towards COX-2 inhibitory activity resulted in statistically significant linear multiple regression equation with r = 0.942, r(2) = 0.888, s = 0.532 and F = 7.92, q(2) = 0.516 for 29 compounds. Fujita-Ban model shows a negative contribution of SO2NH2 and SO2CH3 at the R1 position; a negative contribution of 4-Cl, 2-Cl, 3-Cl, 3-CH3, 4-SO2CH3, 4-Br and a positive contribution of 4-OCH3, 4-CH3 substituents at the R2 position. At the R3 position a negative contribution of F, Br and a positive contribution of Cl, CH3 is encountered. In the light of our preliminary investigation that electron donating groups at the para position of R2 are conducive for COX-2 inhibitory activity from the Fujita-Ban model, we attempted to correlate the COX-2 inhibitory activity with quantum chemical descriptors of semi-empirical AM1 optimized geometries of the title compounds. Correlation analysis showed the molecular electronic descriptor, MOPAC total energy as crucial in governing COX-2 inhibitory activity of all the reported 41 compounds.
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Preparation,In vitro, preclinical and clinical evaluations of once daily sustained release tablets of aceclofenac. Arch Pharm Res 2007; 30:222-34. [PMID: 17366745 DOI: 10.1007/bf02977698] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The objective of the present study was to develop "once daily" sustained release tablets of aceclofenac by direct compression using hydroxypropyl methylcellulose-K4M (HPMC). The solubility studies of aceclofenac were conducted to select suitable dissolution media. The drug-excipient mixtures were subjected to preformulation studies. The tablets were subjected to physicochemical, in vitro drug release and stability studies. Preclinical (anti-inflammatory, analgesic, pharmacokinetic and toxicity studies) and clinical pharmacokinetic studies were conducted for optimized tablets. Based on the preformulation results, microcrystalline cellulose (MCC), dicalcium phosphate and spray dried lactose (SDL) were selected as directly compressible vehicles. Because of the incompatibility with aceclofenac, SDL was excluded from the study. The physicochemical properties of tablets were found within the limits. By comparing the dissolution profiles with the marketed product, the tablet containing HPMC (45%) and MCC (30%) along with talc and magnesium stearate (1% w/w, each) (Tablet B7) was considered as a better formulation. This tablet exhibited almost similar drug release profile in different dissolution media as that of marketed tablet. Tablet B7 was stable in accelerated conditions for 6 months. The composition of this tablet showed almost similar preclinical pharmacological activities compared to marketed tablet composition and did not exhibit any toxicity in rats and mice with respect to tested haematological and biochemical parameters along with body weight, food and water intake. The pharmacokinetic study in healthy human volunteers indicated that B7 tablet produced an extended drug release of drug upto 24 h as that of marketed product with almost identical pharmacokinetic parameters.
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First QSAR report on FSH receptor antagonistic activity: Quantitative investigations on physico-chemical and structural features among 6-amino-4-phenyltetrahydroquinoline derivatives. Bioorg Med Chem Lett 2005; 15:4496-501. [PMID: 16085412 DOI: 10.1016/j.bmcl.2005.07.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 07/04/2005] [Accepted: 07/07/2005] [Indexed: 11/26/2022]
Abstract
A quantitative attempt has been made to correlate the structure-activity relationship (SAR) among the recently reported 6-amino-4-phenyltetrahydroquinoline derivatives as antagonists for the Gs-protein-coupled human follicle-stimulating hormone (FSH) receptor. The compounds used for the present study have been reported to show high antagonistic efficacy in vitro using a CHO-hFSHR(luc) assay. Our QSAR investigations revealed a hydrophobic type of interactions between these ligands and the FSH receptor, hence confirming the presence of a lipophilic pocket on the active site of the target structure. The positive coefficient of ClogP variable in our derived QSAR model suggests that more hydrophobic ligands are crucial for their FSH receptor antagonistic efficacy. In exploring the structural requirements among these congeners, we found an amide linkage as conducive to their FSH receptor antagonistic activity. Also, an unsubstituted 4-phenyl ring of the tetrahydroquinoline scaffold is favorable for their FSH receptor antagonistic activity. The results discussed herein could be useful in understanding the nature of interactions of these newly identified ligands as FSH receptor antagonists and in designing more potent ligands based on this novel 6-amino-4-phenyltetrahydroquinoline scaffold.
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Design, synthesis and biological evaluation of novel bicyclic β-lactams as potential antimalarials. Bioorg Med Chem Lett 2005; 15:1371-3. [PMID: 15713389 DOI: 10.1016/j.bmcl.2005.01.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 01/05/2005] [Accepted: 01/07/2005] [Indexed: 11/24/2022]
Abstract
A series of bicyclic N-substituted and unsubstituted beta-lactams were synthesized and evaluated as targeted potential antimalarials. The compounds MNR4 and MNR5 were found to have highest potency against Plasmodium falciparum in vitro.
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QSAR studies on structurally similar 2-(4-methanesulfonylphenyl)pyran-4-ones as selective COX-2 inhibitors: a Hansch approach. Bioorg Med Chem Lett 2005; 15:313-20. [PMID: 15603946 DOI: 10.1016/j.bmcl.2004.10.077] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 10/22/2004] [Accepted: 10/26/2004] [Indexed: 10/26/2022]
Abstract
QSAR analysis based on classical Hansch approach was adopted on two recently reported novel series of 2-phenylpyran-4-ones as selective cyclooxygenase-2 (COX-2) inhibitors. The 6-methyl derivatives of title compounds bifurcate as 3-phenoxypyran-4-ones (subset A) and 3-phenylpyran-4-ones (subset B) among series 1. Series 2 consists of 5-chloro derivatives of title compounds. Various regression equations were derived to study the influence of phenoxy and phenyl ring substituents of series 1 compounds on COX-2, COX-1 and selective COX-2 over COX-1 inhibitory activity. The best triparametric equation derived for 36 compounds of series 1 explains the hydrophobic, electronic and steric requirements for improved COX-2 inhibitory activity. QSAR model derived to explore the selective COX-2 over COX-1 inhibition showed that selectivity could be influenced by size and lipophilicity of substituents. The size of the first atom of 2 substituents appears to have negative effect on selectivity, whereas highly polar 3 substituents at R are favorable for improved selectivity. QSAR investigations on series 2 compounds revealed some interesting correlation of COX-2 inhibitory activity with calculated physicochemical properties of whole molecules. The positive logP confirms the hydrophobic interaction of series 2 compounds with COX-2 enzyme. The positive MR term indicates that an overall increase in size and polarizabilty of the molecules increases COX-2 inhibitory activity. The positive contribution of structural variable suggests biphenyl analogs are extremely potent COX-2 inhibitors.
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Quantitative structure-activity relationship studies of cyclooxygenase inhibitors: a comprehensive analysis. Drug Dev Res 2005. [DOI: 10.1002/ddr.10432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Rationalization of physico-chemical properties of 5, 6-diarylthiazolo [3,2-b]-1, 2, 4-triazoles towards cyclooxygenase-2 (COX-2) inhibition: a QSAR approach. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 2004; 41:179-183. [PMID: 22900350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Quantitative structure-activity relationship (QSAR) analysis was performed on a series of 5, 6-diarylthiazolo [3, 2-b]-1, 2, 4-triazoles to explore their possible interaction with the active amino acid residues of cyclooxygenase-2 (COX-2) enzyme. The significance of orientation and conformational rigidity of 5, 6-diarylthiazolo [3, 2-b]-1, 2, 4-triazoles for COX-2 inhibition is discerned by the spatial descriptor principle moment of inertia-X component, PMI-X. The negative contribution of PMI-X indicates the necessity of orientation of substituents towards X-axis of aromatic ring for better activity. The most common electronic interaction between the title compounds and active residues of COX-2 enzyme is corroborated well by the positive contribution of molecular dipole. The contribution of molecular dipole suggests the non-covalent, electronic interactions between 5, 6-diarylthiazolo [3, 2-b]-1, 2, 4-triazoles and binding site of COX-2 enzyme. Our findings reveal the necessity of less bulkier, less polar substituents on the parent structure for better COX-2 inhibitory activity. The limited tolerance of COX-2 enzyme active site towards the bulk of interacting molecules is evident from the negative coefficient of calculated molar refractivity (CMR) in our models.
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Quantitative structure–activity relationship analysis of a series of 2,3-diaryl benzopyran analogues as novel selective cyclooxygenase-2 inhibitors. Bioorg Med Chem Lett 2004; 14:4005-11. [PMID: 15225716 DOI: 10.1016/j.bmcl.2004.05.059] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2004] [Revised: 05/18/2004] [Accepted: 05/19/2004] [Indexed: 10/26/2022]
Abstract
A series of recently synthesized 2,3-diaryl benzopyrans reported as novel selective cycloxygenase-2 inhibitors was subjected to quantitative structure-activity relationship (QSAR) analysis. Our attempt in correlating the derived physicochemical properties with the COX-2 inhibitory activity resulted in some statistically significant QSAR models with good predictive ability. The QSAR results and the probable pharmacophore features investigated through our study explored some interesting findings for the design of potent new class of selective COX-2 inhibitors.
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Diagnosis of tuberculous meningitis by ELISA test. Indian J Med Res 1994; 99:8-12. [PMID: 8163303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Detection of IgG antibodies to Mycobacterium tuberculosis H37 Ra antigen in cerebrospinal fluid (CSF), by ELISA test appears to be highly sensitive. In 90 per cent (18/20) of proven cases of tuberculous meningitis (TBM), antibodies were present in CSF; in 75 per cent (15/20) antibodies were also present in the sera. In the patients clinically suspected to have TBM, antibodies in CSF and sera were present in 87.5 per cent (42/48) and 70.8 per cent (34/48) respectively, whereas in the control group antibodies were present in only one serum sample and in none of the CSF samples. The results indicate that ELISA test using sonicated M. tuberculosis H37 Ra as antigen is a sensitive and specific test for diagnosis of TBM.
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