12 results on '"Ghosh, Swarup"'
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2. Strain induced modulations in the thermoelectric properties of 2D SiH and GeH monolayers: insights from first-principle calculations.
- Author
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Banik RR, Ghosh S, and Chowdhury J
- Abstract
The present paper is primarily focused to understand the strain driven alterations in thermoelectric (TE) properties of two-dimensional SiH and GeH monolayers from first-principle calculations. Electronic band structures and the associated TE properties of the compounds under ambient and external strains have been critically unveiled in terms of Seebeck coefficients, electrical conductivities, power factors and electronic thermal conductivities. The phonon dispersion relations have also been investigated to estimate the lattice thermal conductivities of the systems. The TE figure of merits of SiH and GeH monolayers under ambient and external strains have been explored from the collective effects of their Seebeck coefficients, electrical conductivities, electronic and lattice thermal conductivities. The present study will be helpful in exploring the strain induced TE responses of SiH and GeH compounds which in turn may bear potential applications in clean and global energy conservation., (© 2024 IOP Publishing Ltd.)
- Published
- 2024
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3. Predicting band gaps of ABN 3 perovskites: an account from machine learning and first-principle DFT studies.
- Author
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Ghosh S and Chowdhury J
- Abstract
The present paper is primarily focused on predicting the band gaps of nitride perovskites from machine learning (ML) models. The ML models have been framed from the feature descriptors and band gap values of 1563 inorganic nitride perovskites having formation energies <-0.026 eV and band gaps ranging from ∼1.0 to 3.1 eV. Four supervised ML models such as multi-layer perceptron (MLP), gradient boosted decision tree (GBDT), support vector regression (SVR) and random forest regression (RFR) have been considered to predict the band gaps of the said systems. The accuracy of each model has been tested from mean absolute error, root-mean-square error and determination coefficient R
2 values. The bivariate plots between the predicted and input band gaps of the compounds for both the training and test datasets have also been estimated. Additionally, two ABN3 -type nitride perovskites CeBN3 (B = Mo, W) have been selected and their electronic band structures and optoelectronic properties have been studied from density functional theory (DFT) calculations. The band gap values of the said compounds have been estimated from DFT calculations at PBE, HSE06, G0 W0 @PBE, G0 W0 @HSE06 level of theories. The present study will be helpful in exploring the ML models in predicting the band gaps of nitride perovskites which in turn may bear potential applications in photovoltaic cells and optical luminescent devices., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2024
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4. ENResNet: A novel residual neural network for chest X-ray enhancement based COVID-19 detection.
- Author
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Ghosh SK and Ghosh A
- Abstract
Recently, people around the world are being vulnerable to the pandemic effect of the novel Corona Virus. It is very difficult to detect the virus infected chest X-ray (CXR) image during early stages due to constant gene mutation of the virus. It is also strenuous to differentiate between the usual pneumonia from the COVID-19 positive case as both show similar symptoms. This paper proposes a modified residual network based enhancement (ENResNet) scheme for the visual clarification of COVID-19 pneumonia impairment from CXR images and classification of COVID-19 under deep learning framework. Firstly, the residual image has been generated using residual convolutional neural network through batch normalization corresponding to each image. Secondly, a module has been constructed through normalized map using patches and residual images as input. The output consisting of residual images and patches of each module are fed into the next module and this goes on for consecutive eight modules. A feature map is generated from each module and the final enhanced CXR is produced via up-sampling process. Further, we have designed a simple CNN model for automatic detection of COVID-19 from CXR images in the light of 'multi-term loss' function and 'softmax' classifier in optimal way. The proposed model exhibits better result in the diagnosis of binary classification (COVID vs. Normal) and multi-class classification (COVID vs. Pneumonia vs. Normal) in this study. The suggested ENResNet achieves a classification accuracy 99.7 % and 98.4 % for binary classification and multi-class detection respectively in comparison with state-of-the-art methods., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2022
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5. A Novel Human Diabetes Biomarker Recognition Approach Using Fuzzy Rough Multigranulation Nearest Neighbour Classifier Model.
- Author
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Ghosh SK and Ghosh A
- Subjects
- Algorithms, Biomarkers, Cluster Analysis, Humans, Diabetes Mellitus, Fuzzy Logic
- Abstract
The selection of gene identifier from microarray databases is a challenging task since microarray contains large number of gene attributes for a few samples. This article proposes a novel fuzzy-rough set-based gene expression features selection using fuzzy-rough reduct under multi-granular space for human diabetes patient. Firstly, fuzzy multi-granular gain has been computed from the expression datasets via fuzzy entropy which reduces the dimension of the database. Thereafter, the features have been selected from microarray using the fuzzy rough reduct and information gain with respect to their expression patterns. To reduce the computational cost, a decision making scheme has been designed using a rough approximation of a fuzzy concept in the field of multi-granulation framework. Finally, we have recognized the association among the genomes that have expressively different expression patterns from controlled state to the diabetic state with respect to their impression using modified fuzzy-rough nearest neighbour classifier (FRNNC). Five standard diabetic microarray datasets have been considered to quantify the efficiency of the designed FRNNC model and are validated with F measure using diabetes gene expression NCBI database and it performs superior compared to existing methods.
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- 2020
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6. Active Ga-catalysts for the ring opening homo- and copolymerization of cyclic esters, and copolymerization of epoxide and anhydrides.
- Author
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Ghosh S, Glöckler E, Wölper C, Tjaberings A, Gröschel AH, and Schulz S
- Abstract
A series of gallium complexes L12Ga4Me8 (1), L22Ga4Me8 (2), and L32Ga4Me8 (3) was synthesized by reaction of GaMe3 with Schiff base ligands L1-3H2 (L1H2 = 2,4-di-tert-butyl-6-{[(3-hydroxypropyl)imino]methyl}phenol; L2H2 = 2,4-dichloro-6-{[(3-hydroxypropyl)imino]methyl}phenol; L3H2 = 4-tert-butyl-2-{[(3-hydroxypropyl)imino]methyl}phenol) and characterized by 1H, 13C NMR, IR spectroscopy, elemental analysis and single crystal X-ray analysis (1, 2), proving their tetranuclear structure in the solid state. Complexes 1-3 showed good catalytic activity in the ring opening homopolymerization (ROP) and ring opening copolymerization (ROcoP) of lactide (LA) and ε-caprolactone (ε-CL) in the presence of benzyl alcohol (BnOH) in toluene at 100 °C, yielding polymers with the expected average molecular weights (Mn) and narrow molecular weight distributions (MWD), as well as a high isoselectivity for the ROP of rac-lactide (rac-LA), yielding isotactic-enriched PLAs with Pm values up to 0.78. Kinetic studies with complex 1 proved the first order dependence on monomer concentration, while mechanistic studies confirmed the coordination insertion mechanistic (CIM) pathway. Sequential addition of monomers gave well defined diblock copolymers of PCL-b-PLLA and PLLA-b-PCL, proving the living character of the polymerization reactions. The catalysts also showed perfect selectivity for the copolymerization of cyclohexene oxide (CHO) with both succinic anhydride (SA) and maleic anhydride (MA) in the presence of BnOH and produced >99% alternating block copolymers.
- Published
- 2020
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7. Syntheses, structures and catalytic activity of tetranuclear Mg complexes in the ROP of cyclic esters under industrially relevant conditions.
- Author
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Ghosh S, Wölper C, Tjaberings A, Gröschel AH, and Schulz S
- Abstract
Four tetranuclear magnesium complexes were synthesized and fully characterized. They are excellent catalysts for the ring-opening polymerization (ROP) of bulk racemic-lactide (rac-LA) and ε-caprolactone (ε-CL) even with low catalyst loading under industrially relevant conditions without additional co-initiators, yielding polymers with high molecular weight (Mn) and moderately controlled molecular weight distribution (MWD). The polymerization activity depends on the steric and electronic properties of the imino(phenolate) ligands. Kinetic studies of the most active catalyst 1 confirmed that the ROP of rac-LA and ε-CL has a first order dependence on monomer concentration. The ROP of rac-LA and ε-CL using 1-4 with BnOH gave polymers with narrow MWD and a close correlation between Mobsn and Mtheon values. Catalyst 1 was also capable of polymerizing technical-grade rac-LA and ε-CL even with large monomer-to-catalyst ratios ([M]0/[C]0) of up to 10 000 : 1 and without any additional co-initiator. The very high turnover frequencies (TOF) of 9600 h-1 (rac-LA) and 24 000 h-1 (ε-CL) prove that 1 belongs to the most active biocompatible, sustainable and nontoxic ROP catalysts under industrially relevant conditions.
- Published
- 2020
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8. Heterolepic β -Ketoiminate Zinc Phenoxide Complexes as Efficient Catalysts for the Ring Opening Polymerization of Lactide.
- Author
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Ghosh S, Schäfer PM, Dittrich D, Scheiper C, Steiniger P, Fink G, Ksiazkiewicz AN, Tjaberings A, Wölper C, Gröschel AH, Pich A, Herres-Pawlis S, and Schulz S
- Abstract
Zinc phenoxide complexes L
1 ZnOAr 1 - 4 (L1 =Me2 NC2 H4 NC(Me)CHC(Me)O) and L2 ZnOAr 5 - 8 (L2 =Me2 NC3 H6 NC(Me)CHC(Me)O) with donor-functionalized β -ketoiminate ligands (L1/2 ) and OAr substituents (Ar=Ph 1 , 5 ; 2,6-Me2 -C6 H3 2 , 6 ; 3,5-Me2 -C6 H3 3 , 7 ; 4-Bu-C6 H4 4 , 8 ) with tuneable electronic and steric properties were synthesized and characterized. 1 - 8 adopt binuclear structures in the solid state except for 5 , while they are monomeric in CDCl3 solution. 1 - 8 are active catalysts for the ring opening polymerization (ROP) of lactide (LA) in CH2 Cl2 at ambient temperature and the catalytic activity is controlled by the electronic and steric properties of the OAr substituent, yielding polymers with high average molecular weight ( Mn ) and moderately controlled molecular weight distribution (MWDs). 1 and 5 showed a living polymerization character and kinetic studies on the ROP of L -LA with 1 and 5 proved first order dependencies on the monomer concentration. Homonuclear decoupled1 H-NMR analyses of polylactic acid (PLA) formed with rac -LA proved isotactic enrichment of the PLA microstructure., Competing Interests: The authors declare no conflict of interest.- Published
- 2019
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9. Suspecting Hyperferritinemic Sepsis in Iron-Deficient Population: Do We Need a Lower Plasma Ferritin Threshold?
- Author
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Ghosh S, Baranwal AK, Bhatia P, and Nallasamy K
- Subjects
- Anemia, Iron-Deficiency complications, Anemia, Iron-Deficiency mortality, C-Reactive Protein metabolism, Case-Control Studies, Child, Child, Preschool, Humans, India epidemiology, Infant, Malnutrition complications, Organ Dysfunction Scores, Prospective Studies, Shock, Septic complications, Shock, Septic diagnosis, Shock, Septic mortality, Anemia, Iron-Deficiency blood, Ferritins blood, Shock, Septic blood
- Abstract
Objectives: Hyperferritinemia is being suggested to identify patients with sepsis-induced macrophage activation syndrome for early intervention. However, data among iron-deficient children are scarce. This study was planned to explore the biological behavior of plasma ferritin in children from communities with a high frequency of iron deficiency with septic shock and its association with the outcome., Design: Prospective observational study., Setting: Tertiary care teaching hospital in a low-middle income economy of South Asia., Patients or Subjects: Patients (6 mo to 12 yr) (n = 42) with septic shock and their healthy siblings as controls (n = 36). Patients/controls with blood transfusion/iron supplement during last 6 months or with any chronic disease were excluded., Interventions: None., Measurements and Main Results: Ferritin was measured in patients at enrollment and then at 1 month of hospital discharge while they were not on iron supplementation and in controls as indicative of baseline level. Patients' median age was 30 months (13.5-87 mo), 31% were malnourished, majority (86%) had anemia, and two thirds had microcytic hypochromic red cells. Ferritin at admission was 763 ng/mL (480-1,820 ng/mL) in nonsurvivors, whereas 415 ng/mL (262-852 ng/mL) in survivors (p = 0.11). Pediatric Logistic Organ Dysfunction score and C-reactive protein correlated positively with plasma ferritin (p = 0.03 and p = 0.01, respectively) at enrollment. Elevated ferritin of greater than 500 ng/mL (relative risk, 2.48; 95% CI, 0.95-6.43) and greater than 1,000 ng/mL (relative risk, 1.94; 95% CI, 0.94-4.02) were associated with higher mortality but not independently. Among survivors, the 1-month follow-up ferritin fell significantly to 97 ng/mL (16-118 ng/mL) (p = 0.001). However, it was still significantly higher than that in sibling controls (19 ng/mL [10-54 ng/mL]) (p = 0.003)., Conclusions: Ferritin rises significantly in septic shock patients despite iron deficiency and seems to correlate with the severity of inflammation and organ dysfunction. Even a lower threshold (of 500 or 1,000 ng/mL) could predict higher mortality. It may suggest the need for redefining the plasma ferritin threshold for suspecting hyperferritinemic sepsis and sepsis-induced macrophage activation syndrome in these patients. Larger studies with frequent ferritin measurements are desirable to validate these initial observations.
- Published
- 2018
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10. Acanthocytosis in progressive childhood dystonia.
- Author
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Sharawat IK, Ghosh S, Bhatia P, Bhatia V, and Saini AG
- Subjects
- Child, Humans, Male, Pantothenate Kinase-Associated Neurodegeneration genetics, Pantothenate Kinase-Associated Neurodegeneration pathology, Abetalipoproteinemia genetics, Dystonic Disorders genetics, Pantothenate Kinase-Associated Neurodegeneration complications
- Abstract
Competing Interests: There are no conflicts of interest
- Published
- 2018
- Full Text
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11. A Study of Correlation Between Clinical and Histopathological Findings of Erythroderma in North Bengal Population.
- Author
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Banerjee S, Ghosh S, and Mandal RK
- Abstract
Background: Erythroderma is a reaction pattern characterized by erythema and desquamation of 90% or more body surface area along with some metabolic alterations., Materials and Methods: Here we studied 32 patients of erythroderma at of North Bengal Medical College for a period of 1 year to find the etiology, clinical features and histological changes. Detailed history was taken from all the patients followed by relevant biochemical investigations and histological examination. To correlate the clinical and histopathological findings chi square test was used., Results: Male preponderance was present and most of them were in the 4(th) or 5(th) decade. Etiologically the patients were divided into secondary erythroderma developing over pre-existing dermatoses, and idiopathic erythroderma. Secondary erythroderma (n = 24) cases outnumbered the idiopathic cases (n = 8). Among the pre-existing dermatoses, psoriasis was found to be the most common etiologic agent. Apart from erythema the other common presenting features were scaling and itching. Histopathological categorization was possible in 59.3% cases, rest of the cases showed non-specific dermatitis. The most common histopathologic diagnosis was psoriasis (21.8% of cases)., Conclusions: Our study of clinicopathological correlation of erythroderma patients among north bengal population corroborates with most of the previous studies done in other areas. As ours is a cross-sectional study in a undefined population so we could not determine the true incidence of erythroderma in north bengal population. We might have missed lymphoma as a cause of erythroderma in idiopathic cases due to lack of long follow-up, so we understand that further studies over a defined population with long follow-up is needed to determine the true incidence and causes of idiopathic erythroderma.
- Published
- 2015
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12. Gallium and indium complexes containing the bis(imino)phenoxide ligand: synthesis, structural characterization and polymerization studies.
- Author
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Ghosh S, Gowda RR, Jagan R, and Chakraborty D
- Subjects
- Ligands, Molecular Structure, Polymerization, X-Ray Diffraction, Coordination Complexes chemistry, Gallium chemistry, Imines chemistry, Indium chemistry, Phenols chemistry
- Abstract
A series of gallium and indium complexes containing a bis(imino)phenolate ligand framework were synthesized and completely characterized with different spectroscopic techniques. The molecular structures of a few complexes were determined using single crystal X-ray diffraction studies. These compounds were found to be extremely active towards the bulk ring opening polymerization (ROP) of lactides yielding polymers with high number average molecular weight (Mn) and controlled molecular weight distributions (MWDs). The neutral complexes produce isotactic enriched poly(lactic acid) (PLA) from rac-lactide (rac-LA) under melt conditions, whereas the ionic complex produces atactic PLA. The polymerizations are controlled, as evidenced by the narrow molecular distribution (MWDs) of the isolated polymers in addition to the linear nature of number average molecular weight (Mn) versus conversion plots with variations in monomer to catalyst ratios. The kinetic and mechanistic studies associated with these polymerizations have been performed.
- Published
- 2015
- Full Text
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