79 results on '"Dipankar Ghosh"'
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2. Impact of COVID-19 on heart failure hospitalization and outcome in India – A cardiological society of India study (CSI–HF in COVID 19 times study – 'The COVID C–HF study')
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Jayagopal P. B, Ramakrishnan S, Mohanan P. P, Jabir A, Venugopal K, M.K. Das, Santhosh K, Syam N, J. Ezhilan, Rajeev Agarwal, Vaidyanathan P R, Ahmed Hussain Choudhary, Meena C B, Amit Malviya, Arun Gopi, Chopra V K, Stigi Joseph, Krishna Kishore Goyal, John F. John, Sandeep Bansal, Harikrishnan S, Praveen Nagula, Johny Joseph, Ajit Bagawat, Sandeep Seth, Urmil Shah, Pravin K. Goel, P.K. Asokan, K.K. Sethi, Satyavan Sharma, (Lt.Gen)Anup Banerji, Sunandan Sikdar, ManojKumar Agarwala, Sharad Chandra, BishwaBhushan Bharti, S.M. Ashraf, Smit Srivastava, B. Kesavamoorthy, Harinder Kumar Bali, Dipak Sarma, Rajendra Kumar Jain, Sameer I. Dani, B.H. Natesh, Rabindra Nath Chakraborty, Vivek Gupta, Narendra Nath Khanna, Dipankar Mukhopadhyay, Subroto Mandal, Biswajit Majumder, Sridhar L, Meennahalli Palleda Girish, DipakRanjan Das, Tom Devasia, Bhavesh Vajifdar, Tanuj Bhatia, Zia Abdullah, Sanjeev Sharma, Sudeep Kumar, Mathew Lincy, Nitish Naik, Dhiman Kahali, Dhurjati Prasad Sinha, Dipankar Ghosh Dastidar, Gurpreet Sing Wander, Rakesh Yadav, Satyendra Tewari, Suman Bhandari, Pratap Chandra Rath, Vijay Harikisan Bang, Debabrata Roy, ParthoSarathi Banerjee, S. Shanmugasundaram, and Geevar Zachariah
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COVID-19 ,Acute heart failure ,Acute decompensated heart failure ,GDMT in heart failure ,Surgery ,RD1-811 ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Objectives: The presentation and outcomes of acute decompensated heart failure (ADHF) during COVID times (June 2020 to Dec 2020) were compared with the historical control during the same period in 2019. Methods: Data of 4806 consecutive patients of acute HF admitted in 22 centres in the country were collected during this period. The admission patterns, aetiology, outcomes, prescription of guideline-directed medical therapy (GDMT) and interventions were analysed in this retrospective study. Results: Admissions for acute heart failure during the pandemic period in 2020 decreased by 20% compared to the corresponding six-month period in 2019, with numbers dropping from 2675 to 2131. However, no difference in the epidemiology was seen. The mean age of presentation in 2019 was 61.75 (±13.7) years, and 59.97 (±14.6) years in 2020. There was a significant decrease in the mean age of presentation (p = 0.001). Also. the proportion of male patients decreased significantly from 68.67% to 65.84% (p = 0.037). The in-hospital mortality for acute heart failure did not differ significantly between 2019 and 2020 (4.19% and 4.,97%) respectively (p = 0.19). The proportion of patients with HFrEF did not change in 2020 compared to 2019 (76.82% vs 75.74%, respectively). The average duration of hospital stay was 6.5 days. Conclusion: The outcomes of ADHF patients admitted during the Covid pandemic did not differ significantly. The length of hospital stay remained the same. The study highlighted the sub-optimal use of GDMT, though slightly improving over the last few years.
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- 2023
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3. COVID-19 infected ST-Elevation myocardial infarction in India (COSTA INDIA)
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Abdullakutty Jabir, Geevar Zachariah, Padinhare Purayil Mohanan, Mohit Dayal Gupta, Sivasubramanian Ramakrishnan, Chandra Bhan Meena, L. Sridhar, Meennahalli Palleda Girish, Dipak Ranjan Das, Anshul Gupta, Praveen Nagula, Tom Devasia, Bhavesh Vajifdar, Kamlesh Thakkar, Urmil Shah, Tanuj Bhatia, Smit Srivastava, Sanjeev Sharma, Priya Kubendiran, Pathiyil Balagopalan Jayagopal, Sudeep Kumar, Deepthy Sadanandan, Lincy Mathew, Nitish Naik, Anup Banerji, S.M. Ashraf, P.K. Asokan, Bishwa Bhushan Bharti, Biswajit Majumder, Dhiman Kahali, Dhurjati Prasad Sinha, Dipak Sharma, Dipankar Ghosh Dastidar, Dipankar Mukhapdhyay, Gurpreet Sing Wander, Harinder Kumar Bali, B. Kesavamoorthy, Manoj Kumar Agarwala, Narendra Nath Khanna, B.H. Natesh, Pravin K. Goel, Rabindra Nath Chakraborty, Rajendra Kumar Jain, Rakesh Yadav, L. Sameer Dani, Satyavan Sharma, Satyendra Tewari, K.K. Sethi, Sharad Chandra, Subrato Mandal, Suman Bhandari, Sundandan Sikdar, Vivek Gupta, Pratap Chandra Rath, Vijay Harikisan Bang, Debabrata Roy, Mrinal Kanti Das, and Partho Sarathi Banerjee
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COVID positive STEMI ,MI during COVID ,STEMI and COVID ,STEMI during COVID ,STEMI management ,Surgery ,RD1-811 ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Objective: To find out differences in the presentation, management and outcomes of COVID-19 infected STEMI patients compared to age and sex-matched non-infected STEMI patients treated during the same period. Methods: This was a retrospective multicentre observational registry in which we collected data of COVID-19 positive STEMI patients from selected tertiary care hospitals across India. For every COVID-19 positive STEMI patient, two age and sex-matched COVID-19 negative STEMI patients were enrolled as control. The primary endpoint was a composite of in-hospital mortality, re-infarction, heart failure, and stroke. Results: 410 COVID-19 positive STEMI cases were compared with 799 COVID-19 negative STEMI cases. The composite of death/reinfarction/stroke/heart failure was significantly higher among the COVID-19 positive STEMI patients compared with COVID-19 negative STEMI cases (27.1% vs 20.7% p value = 0.01); though mortality rate did not differ significantly (8.0% vs 5.8% p value = 0.13). Significantly lower proportion of COVID-19 positive STEMI patients received reperfusion treatment and primary PCI (60.7% vs 71.1% p value=< 0.001 and 15.4% vs 23.4% p value = 0.001 respectively). Rate of systematic early PCI (pharmaco-invasive treatment) was significantly lower in the COVID-19 positive group compared with COVID-19 negative group. There was no difference in the prevalence of high thrombus burden (14.5% and 12.0% p value = 0.55 among COVID-19 positive and negative patients respectively) Conclusions: In this large registry of STEMI patients, we did not find significant excess in in-hospital mortality among COVID-19 co-infected patients compared with non-infected patients despite lower rate of primary PCI and reperfusion treatment, though composite of in-hospital mortality, re-infarction, stroke and heart failure was higher.
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- 2023
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4. Lignocellulolytic Microbial Systems and its Importance in Dye Decolourization: A Review
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Somnath Das, Ankita Gole, Annesha Chakraborty, Supriyo Mal, Shilpa Rudra, and Dipankar Ghosh
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dye decolourization ,lignocellulolytic enzymes ,microbial consortia ,genetic engineering ,Microbiology ,QR1-502 - Abstract
Effluents containing dyes from different industrial sectors pose a serious threat to the environment. Different physicochemical strategies are being carried out in industry to reduce the toxicity of dye-containing waste so that dye-mixed wastewater can be further utilized in agriculture or irrigation purposes in water-scarce areas. But those techniques are economically not feasible. There is an alternative mechanism present in biological systems that are biocatalysts which is eco-friendly, low cost, and sustainable. Lignin peroxidase, Laccase, Manganese peroxidase are oxidoreductase classes of enzymes with the ligninolytic ability and are potential biocatalysts for the degradation of environmental toxicants like dyes. Besides ligninolytic enzymes, cellulase, pectinase are also powerful candidates for dye decolourization. Most interestingly these biocatalysts are found in a variety of microbial monoculture as well as in mixed microbial consortia. The consortia are able to reduce the organic load of dye-containing industrial effluent at a higher rate rather than the monoculture. This article critically reviews the efficacy of lignocellulolytic enzymes in dye decolourization by both monoculture and consortia approaches. In addition, this review discusses the genetically and metabolically engineered microbial systems that contribute to dye decolourization as well as put forward some future approaches for the enhancement of dye removal efficacy.
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- 2023
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5. Qualitative and Quantitative Studies on Biopigment Producing Algal Regime from Marine Water Resources of Sundarban Region
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Shrestha Debnath and Dipankar Ghosh
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algal pigment ,isolation ,screening ,extraction ,quantification ,marketability ,Microbiology ,QR1-502 - Abstract
The current scientific studies have shown that extensive quantities of synthetic pigments are used worldwide in diverse industries. Synthetic pigments have shown enormous toxicity issues compared to natural colorants and dyes in current industrial usage. Diverse microbial communities, including fungi, bacteria, archaea, and yeast are current biopigment producers. However, the aforementioned biopigments are expensive, least efficient, and less eco-friendly to attain industrial sustainability. Thus, algae-based bio pigments are one of the best natural resources to meet today’s challenges. Algal pigments increase the product’s marketability and carry multiple therapeutic properties, including antioxidant, anti-inflammatory, and neuroprotective actions. These multidimensional qualities of algal pigments have piqued the interest of the food, pharmaceutical, cosmetic, and nutraceutical industries resulting in most potential implementation. Thus, a paradigm shift requires identifying potential algal communities having a higher biopigment-producing ability for future manufacturing and commercialization as a sustainable way forward. Hence, the current study has been designed for effective isolation and screening of algal isolates (i.e. DS1, DS2, DS3, DS4, DS5) from a different region of sundarban water resources concerning the investigation of algal pigments (i.e. chlorophyll-a, chlorophyll-b and carotenoid). In a nutshell, the current study shows that DS2 isolate produces a significant quantity of carotenoid (9.729 mg/g DCW), chlorophyll a (7.872 mg/g DCW), and chlorophyll b (7.176 mg/g DCW) amongst all isolates. Hence, the present study reveals that DS2 algal isolates might be a potential predecessor of biopigment production, having pivotal applications in food, pharmaceutical, cosmetic, and nutraceutical industries in the near future.
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- 2023
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6. Isolation and Screening of Dye Degrading Lignocellulolytic Bacteria from Sundarban Mangrove Ecosystem, West Bengal, India
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Somnath Das, Nilothpal Sinha, Mitun Sen, and Dipankar Ghosh
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laccase ,cellulase ,pectinase ,dye-decolorization ,enzyme activity ,Microbiology ,QR1-502 - Abstract
The present research work was carried out on isolating lignocellulolytic enzyme-producing natural bacterial isolates of the Sundarban Mangrove ecosystem in West Bengal, India. Multiple bacterial isolations and qualitative as well as quantitative screening of the isolates was conducted by selective media plates and dye decolorization assay. Growth characterization of the top three isolates, namely GD1, GD2, and GD3, was determined in both nutrient broth and selective media. GD1 showed laccase activity in ABTS plate and decolorized congo red, malachite green, and methylene blue by 64.82%, 47.69%, and 33.33%, respectively, which is the inherent property of laccase. Along with the maximum laccase activity (9.72U/L), it also showed a little amount of cellulase (5.8U/ml) and pectinase (0.55U/ml) activity in the enzyme assay. GD2 showed maximum cellulase activity (6.56U/ml) with only 3.3% degradation of congo red and 39.43% degradation of malachite green. Like GD1, GD2 also bears 5.6U/L laccase and 0.12U/ml pectinase enzyme activity. The last isolate, GD3 specialized in pectinase production and having 4.4U/ml enzyme activity, degraded congo red by 66.75% and malachite green by 54.26%.All isolates showed activity between 30° and 37°C, and pH ranges from 4.5 to 7. The outcomes of this research will be useful in the fiber industry like jute or banana, dye industry, pulp-paper industry, and textile industry for waste remediation, recycling, and fiber modification.
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- 2023
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7. Fine‐Tuning Supramolecular Assemblies by Controlling Micellar Aggregates
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Dipankar Ghosh, Libby J. Marshall, Giuseppe Ciccone, Wanli Liu, Adam Squires, Annela Seddon, Massimo Vassalli, and Dave J. Adams
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dipeptides ,gel noodles ,micelles ,nanoindentation ,SAXS ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract Supramolecular assembly can be used to fabricate complex functional materials by organizing simple building blocks. However, it is difficult to control the hierarchical assembly across multiple length scales. The correlation of a supramolecular gel network and a pre‐gelling aggregate will help to understand how a molecular‐level assembly is translated into a higher order. Here, a functional dipeptide 2NapFF is used that can assemble in different micellar structures at high pH by varying the counterion. Replacing the counterions with a divalent calcium salt results in a cross‐linked gel network, or an interesting analog “gel noodles.” The physical properties of the gel noodles can be varied by choosing specific micellar assemblies as the pre‐gel. The mechanical rigidity of the gel networks is compared by nanoindentation and tensile testing, and the pattern to the structures of the micelles observed by small‐angle X‐ray scattering is correlated. The supramolecular assembly can be fine‐tuned by using different micelles as the pre‐gel without affecting the inherent gel‐state properties.
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- 2023
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8. Strain echocardiography in predicting LV dysfunction in RV apical pacing
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Goutam Datta, Dipankar Ghosh Dastidar, and Hrishikesh Chakraborty
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Strain Echocardiography ,RV apical pacing ,LV dysfunction ,Heart failure ,GLS ,Surgery ,RD1-811 ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Right ventricular (RV) pacing is associated with a reduction in left ventricular (LV) systolic function, thought to be mediated by pacing-induced ventricular dyssynchrony. The prevalence of heart failure after RV pacing is reported to range from 31±3%. We studied 60 subjects with high-grade atrioventricular block and Complete Heart Block (CHB) scheduled to undergo right ventricular apical pacing. 2D echocardiography was done at baseline, 1 month and 12 months. Pacing-induced cardiomyopathy was defined as a reduction in LVEF to
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- 2023
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9. An Outcome Analysis of Asymptomatic COVID-19 Patients Presenting with Angina- A Retrospective Study
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Dipankar Ghosh Dastidar, Rakhi Sanyal, Nandita Ghosh Dastidar, and Tirna Halder
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cardiovascular diseases ,myocardial infarction ,thrombolysis ,Medicine - Abstract
Introduction: Cardiovascular disorders have long been considered as one of the leading causes of mortality in India, which when presented with concurrent Coronavirus Disease (COVID-19) infection becomes even more fatal. Evidence suggests that COVID-19 affects the cardiovascular system by causing exuberant cytokinaemia, which results in endothelial inflammation and microvascular thrombosis, leading to multiorgan failure. Aim: To analyse the outcome of the asymptomatic COVID-19 patients presenting with cardiac angina during the second wave of COVID-19 in India. Materials and Methods: This is a retrospective data analysis of asymptomatic COVID-19 patients hospitalised with angina was conducted between April 2021 to June 2021 at Bardhhaman Medical College and Hospital located at Bardhdhaman district of West Bengal, India. A total of 1235 patients underwent all regular biochemical, haematological and cardiac investigations after undergoing test for COVID-19 test. Data was retrospectively collected. The outcome of these patients was analysed. Estimation of mean, standard deviation, percentage, p-value (from Pearson’s correlation) was performed to establish the aim of the study. Results: Seventy six out of 1235 patients tested positive for asymptomatic COVID-19. The mean age of this study population was 55.075±10.95 years, of which were 55 male and 21 female. Hypertension was the most prevalent co-morbidity followed by diabetes, 73 (96%) presented with chest pain. A total of 47(62%) of these 76 patients had ST Elevated Myocardial Infarction (STEMI). Eleven (14.4%) underwent Percutaneous Coronary Intervention (PCI) whereas 36 (47.3%) underwent fibrinolytic therapy with tenecteplase, followed by secondary PCI in 27 (75%) of them. Rest 29 (38%) were medically managed for unstable angina. Mortality rate was as low as 6.5%. Age and comorbidity were the contributing factors for STEMI among asymptomatic COVID-19 patients. Conclusion: The results indicate that age and comorbidity are the factors, which lead to death or increases the life risk among patients with asymptomatic COVID-19. In this study, we have established that for the current patient population STEMI and age are negatively corelated. Medical management with thrombolytic agent became a lot more accepted in this scenario. PCI still remains the gold standard to treat myocardial infarction. It is recommended that there should be an ICMR guided protocol for the management of such cases with the concurrent COVID-19.
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- 2023
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10. Stimuli-Responsive Properties of Supramolecular Gels Based on Pyridyl-N-oxide Amides
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Sreejith Sudhakaran Jayabhavan, Baldur Kristinsson, Dipankar Ghosh, Charlène Breton, and Krishna K. Damodaran
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supramolecular gels ,isomeric LMWGs ,pyridyl N-oxide ,stimuli-responsive systems ,anion/cation-responsive gels ,metallogels ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
The nature of functional groups and their relative position and orientation play an important role in tuning the gelation properties of stimuli-responsive supramolecular gels. In this work, we synthesized and characterized mono-/bis-pyridyl-N-oxide compounds of N-(4-pyridyl)nicotinamide (L1–L3). The gelation properties of these N-oxide compounds were compared with the reported isomeric counterpart mono-/bis-pyridyl-N-oxide compounds of N-(4-pyridyl)isonicotinamide. Hydrogels obtained with L1 and L3 were thermally and mechanically more stable than the corresponding isomeric counterparts. The surface morphology of the xerogels of di-N-oxides (L3 and diNO) obtained from the water was studied using scanning electron microscopy (SEM), which revealed that the relative position of N-oxide moieties did not have a prominent effect on the gel morphology. The solid-state structural analysis was performed using single-crystal X-ray diffraction to understand the key mechanism in gel formation. The versatile nature of N-oxide moieties makes these gels highly responsive toward an external stimulus, and the stimuli-responsive behavior of the gels in water and aqueous mixtures was studied in the presence of various salts. We studied the effect of various salts on the gelation behavior of the hydrogels, and the results indicated that the salts could induce gelation in L1 and L3 below the minimum gelator concentration of the gelators. The mechanical properties were evaluated by rheological experiments, indicating that the modified compounds displayed enhanced gel strength in most cases. Interestingly, cadmium chloride formed supergelator at a very low concentration (0.7 wt% of L3), and robust hydrogels were obtained at higher concentrations of L3. These results show that the relative position of N-oxide moieties is crucial for the effective interaction of the gelator with salts/ions resulting in LMWGs with tunable properties.
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- 2023
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11. A fractional order SITR mathematical model for forecasting of transmission of COVID-19 of India with lockdown effect
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S.S. Askar, Dipankar Ghosh, P.K. Santra, Abdelalim A. Elsadany, and G.S. Mahapatra
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Fractional differential equation ,COVID-19 ,SITR compartmental model ,Stability ,Refuge ,Reproduction number ,Physics ,QC1-999 - Abstract
In this paper, we consider a mathematical model to explain, understanding, and to forecast the outbreaks of COVID-19 in India. The model has four components leading to a system of fractional order differential equations incorporating the refuge concept to study the lockdown effect in controlling COVID-19 spread in India. We investigate the model using the concept of Caputo fractional-order derivative. The goal of this model is to estimate the number of total infected, active cases, deaths, as well as recoveries from COVID-19 to control or minimize the above issues in India. The existence, uniqueness, non-negativity, and boundedness of the solutions are established. In addition, the local and global asymptotic stability of the equilibrium points of the fractional-order system and the basic reproduction number are studied for understanding and prediction of the transmission of COVID-19 in India. The next step is to carry out sensitivity analysis to find out which parameter is the most dominant to affect the disease’s endemicity. The results reveal that the parameters η,μ and ρ are the most dominant sensitivity indices towards the basic reproductive number. A numerical illustration is presented via computer simulations using MATLAB to show a realistic point of view.
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- 2021
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12. Improved thermal conductivity and AC dielectric breakdown strength of silicone rubber/BN composites
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Maryam Sarkarat, Michael Lanagan, Dipankar Ghosh, Andrew Lottes, Kent Budd, and Ramakrishnan Rajagopalan
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Silicone rubber composite ,Thermal conductivity ,AC breakdown strength ,Hexagonal boron nitride (h-BN) ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
The present study demonstrates a synergistic effect with the addition of low loading levels of boron nitride filler in silicone rubber that resulted in significant improvement in both ac breakdown strength and thermal conductivity of silicone rubber composites. Our results show that addition of 2.5 vol% and 7 vol% of h-BN platelets improved thermal conductivity of silicone rubber composites by 25% and 65% respectively. The ac breakdown strength of silicone rubber composites was investigated by varying surface area and particle size of hexagonal boron nitride (h-BN) platelets. The breakdown strength of composites with only 2.5 vol% of low surface area boron nitride (0075) was enhanced by 20% and with high surface area boron nitride (7HS) was improved by 30%. The improvement in ac breakdown strength was primarily attributed to effective heat dissipation in the composite as well as low dielectric loss performance of the composite and was dependent upon the textural properties of boron nitride fillers.
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- 2020
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13. Resolution of Papilledema Following Ventriculoperitoneal Shunt or Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus: A Pilot Study
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Sukriti Das, Nicola Montemurro, Musannah Ashfaq, Dipankar Ghosh, Asit Chandra Sarker, Akhlaque Hossain Khan, Sharbari Dey, and Bipin Chaurasia
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endoscopic third ventriculostomy ,ETV ,neurosurgery ,obstructive hydrocephalus ,papilledema ,ventriculoperitoneal shunt ,Medicine (General) ,R5-920 - Abstract
Background and Objectives: Ventriculoperitoneal Shunt (VPS) and Endoscopic Third Ventriculostomy (ETV) are both gold standard procedures to reduce intracranial pressure (ICP) in patients with obstructive hydrocephalus, which often results in papilledema. This comparative study was carried out at the Department of Neurosurgery of Dhaka Medical College and Hospital to compare the efficacy of VPS and ETV in the resolution of papilledema in 18 patients with obstructive hydrocephalus. Materials and Methods: The success of CSF diversion was evaluated by a decrease in retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) and modified Frisen grading of papilledema at the same time. The statistical analyses were carried out by using paired sample t test and the Spearman’s correlation coefficient test. The level of significance (p value) was set at Results: After 7 days, both VPS and ETV were able to reduce RNFL thickness of both eyes with a p value = 0.016 (right eye) and 0.003 (left eye) in group A (VPS) and with a p value p value > 0.05. Further, the inter-group comparison between VPS and ETV showed no difference in decreasing RNFL thickness and modified Frisen grading (p value = 0.56). Conclusion: VPS and ETV procedures both appear very efficient in treating obstructive hydrocephalus, which in turn reduces papilledema in these patients. This paper is preliminary and requires further work.
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- 2022
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14. Degradation and Stability of Polymeric High-Voltage Insulators and Prediction of Their Service Life through Environmental and Accelerated Aging Processes
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Dipankar Ghosh and Dipak Khastgir
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Chemistry ,QD1-999 - Published
- 2018
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15. Making and Breaking of Gels: Stimuli-Responsive Properties of Bis(Pyridyl-N-oxide Urea) Gelators
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Sreejith Sudhakaran Jayabhavan, Dipankar Ghosh, and Krishna K. Damodaran
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LMWGs ,stimuli-responsive ,structural modification ,pyridyl urea ,pyridyl-N-oxide ,Organic chemistry ,QD241-441 - Abstract
The structural modification of existing supramolecular architecture is an efficient strategy to design and synthesize supramolecular gels with tunable and predictable properties. In this work, we have modified bis(pyridyl urea) compounds with different linkers, namely hexylene and butylene, to their corresponding bis(pyridyl-N-oxide urea). The gelation properties of both the parent and the modified compounds were studied, and the results indicated that modification of the 3-pyridyl moieties to the corresponding 3-pyridyl-N-oxides induced hydrogelation. The stability of the parent and modified compounds were evaluated by sol-gel transition temperature (Tgel) and rheological measurements, and single-crystal X-ray diffraction was used to analyze the solid-state interactions of the gelators. The morphologies of the dried gels were analyzed by scanning electron microscopy (SEM), which revealed that the structural modification did not induce any prominent effect on the gel morphology. The stimuli-responsive behavior of these gels in the presence of salts in DMSO/water was evaluated by rheological experiments, which indicated that the modified compounds displayed enhanced gel strength in most cases. However, the gel network collapsed in the presence of the chloride salts of aluminum(III), zinc(II), copper(II), and cadmium(II). The mechanical strength of the parent gels decreased in the presence of salts, indicating that the structural modification resulted in robust gels in most cases. The modified compounds formed gels below minimum gel concentration in the presence of various salts, indicating salt-induced gelation. These results show the making and breaking ability of the gel network in the presence of external stimuli (salts), which explains the potential of using LMWGs based on N-oxide moieties as stimuli-responsive materials.
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- 2021
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16. Efficiency of Pollution Tolerance Index (PTI) of macroinvertebrates in detecting aquatic pollution in an oxbow lake in India
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Dipankar Ghosh and Jayanta Kumar Biswas
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aquatic health ,diversity indexes ,macroinvertebrates ,pollution ,water quality. ,Science (General) ,Q1-390 - Abstract
This paper evaluates the efficiency of a macroinvertebrate-based Pollution Tolerance Index (PTI) in detecting aquatic pollution in the Chhariganga oxbow lake in India. In this lake, calculated PTIs were compared with results from an array of physicochemical water and sediment parameters and to a macroinvertebrate diversity assessment conducted in parallel for the same lake. The obtained PTI values fell in a range (between 20 and 31) that are indicative of an absence of organic pollution according to the literature, and are normally reported for systems devoid of anthropogenic activity (for instance no monsoonal polluting jute retting activities). However, in the light of the results for the assessed water and sediment physicochemical parameters, and the support of diversity indexes of macroinvertebrates, using data from the same lake, it was possible to conclude that the obtained PTI values do not reflect the true pollution status of this oxbow lake. As PTI values and diversity indexes contradict each other in detecting pollution, it is advised to take both parameters into consideration when using macroinvertebrates to assess aquatic health.
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- 2017
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17. Catch per unit efforts and impacts of gears on fish abundance in an oxbow lake ecosystem in Eastern India
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Dipankar Ghosh and Jayanta Kumar Biswas
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Fish abundance ,Fishing gears ,CPUE ,Oxbow lake ,Environmental sciences ,GE1-350 - Abstract
Background: Oxbow lakes are abundant in indigenous fishes, but they are subject to unsustainable fishing practices, potential overexploitation, and indiscriminate use of fine-meshed fishing gear. To quantify the catch per unit effort (CPUE) and impact of fishing gears on fish abundance, a survey was carried out in an oxbow lake in eastern India. Methods: The gear-wise CPUE for fish caught in per unit hour of operation was calculated by dividing the total sampling gear catch in biomass, which is the observed value of fish caught by a particular gear, by the total sampling effort hours. A value of P < 0.05 was accepted as statistical significance. Results: Average annual values of the CPUE of triangular push nets, gill nets, long lines, seine nets, drag nets, stationary dip nets, cone-framed cast nets, and line and hook were calculated as 328.34, 4.12, 36.71, 572.92, 3928.57, 237.78, 235.80, and 0.44 grams of fish per hour of operation, respectively. All the 8 different gears exhibited lower CPUE during monsoon and post-monsoon seasons than in the premonsoon season. The line and hook was dominant (>71%). Cone-framed cast net hauled the maximum catch in biomass (31.51%), and gill nets contributed the maximum number of fish (64.92%). The lower CPUE values of line and hook, gill net, cone-framed cast net and long lines identified them as the most harmful among all gears. Conclusion: Indiscriminate use of gear, particularly line and hook, gill nets, cone-framed cast nets, and long lines, demands regulations and preventions concerning such gear to obtain higher fish abundance.
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- 2017
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18. Solid-State Structural Transformation and Photoluminescence Properties of Supramolecular Coordination Compounds
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Dipankar Ghosh, Oddný Ragnarsdóttir, Daníel Arnar Tómasson, and Krishna K. Damodaran
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supramolecular coordination materials ,hydrogen bonding ,crystal-to-crystal transformation ,Hirshfeld surface analysis ,photoluminescence ,Mathematics ,QA1-939 - Abstract
The combination of strong coordination bonds and hydrogen bonding interactions were used to generate a series of supramolecular coordination materials (SCMs), which was achieved by reacting a bis-pyridyl amide ligand, namely N-(4-pyridyl)nicotinamide (4PNA) with copper(II), zinc(II), and cadmium(II) benzoates. The SCMs were structurally characterized using X-ray diffraction and the key intermolecular interactions were identified via Hirshfeld surface analysis. The role of solvent molecules on the supramolecular architecture was analyzed by synthesizing the SCMs in different solvents/solvent mixtures. A solvent-mediated solid-state structural transformation was observed in copper(II) SCMs and we were able to isolate the intermediate form of the crystal-to-crystal transformation process. The luminescence experiments revealed that complexation enhanced the fluorescence properties of 4PNA in the zinc(II) and cadmium(II) SCMs, but a reverse phenomenon was observed in the copper(II) SCMs. This work demonstrated the tuning of supramolecular assembly in coordination compounds as a function of solvents for generating SCMs with diverse properties.
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- 2021
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19. Role of N–Oxide Moieties in Tuning Supramolecular Gel-State Properties
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Dipankar Ghosh, Ragnar Bjornsson, and Krishna K. Damodaran
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LMWGs ,hydrogen bonding ,pyridyl urea ,N–oxide ,structural modification ,computational calculations ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
The role of specific interactions in the self-assembly process of low molecular weight gelators (LMWGs) was studied by altering the nonbonding interactions responsible for gel formation via structural modification of the gelator/nongelator. This was achieved by modifying pyridyl moieties of bis(pyridyl) urea-based hydrogelator (4–BPU) and the isomer (3–BPU) to pyridyl N–oxide compounds (L1 and L2, respectively). The modification of the functional groups resulted in the tuning of the gelation properties of the parent gelator, which induced/enhanced the gelation properties. The modified compounds displayed better mechanical and thermal stabilities and the introduction of the N–oxide moieties had a prominent effect on the morphologies of the gel network, which was evident from the scanning electron microscopy (SEM) images. The effect of various interactions due to the introduction of N–oxide moieties in the gel network formation was analyzed by comparing the solid-state interactions of the compounds using single crystal X-ray diffraction and computational studies, which were correlated with the enhanced gelation properties. This study shows the importance of specific nonbonding interactions and the spatial arrangement of the functional groups in the supramolecular gel network formation.
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- 2020
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20. Macroinvertebrate diversity indices: A quantitative bioassessment of ecological health status of an oxbow lake in Eastern India
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Dipankar Ghosh and Jayanta Kumar Biswas
- Subjects
oxbow lake ,macroinvertebrate ,diversity index ,aquatic health ,bioassessment ,Environmental sciences ,GE1-350 ,Medicine - Abstract
Aquatic macroinvertebrates, which play a significant role in the food chain of an ecosystem, are used in fresh water quality assessment to identify the environmental stress resulting from a variety of anthropogenic disturbances. Seasonal surveys of macroinvertebrate communities were conducted from April 2013 to March 2014 in Chhariganga oxbow lake of Nadia District of West Bengal, an eastern state of India. In order to bioassess water quality and aquatic health analysis using diversity indices, viz. Shannon-Wiener and Simpson’s diversity index, species richness and evenness, and total abundance with composition trends were carried out. Taxon richness values of 14, 14, and 18, evenness values of 0.80, 0.71, and 0.73, Shannon-Wiener Index values of 2.10, 1.88, and 2.12, and Simpson’s index values of 0.15, 0.22, and 0.20 were determined for macroinvertebrates found during pre-monsoon, monsoon, and post-monsoon period, respectively. In the present study, low diversity indices, like the Shannon-Wiener Index, demonstrated clearly that the selected lake is polluted and has high anthropogenic activity which has rendered the lake bad to poor health status especially during monsoon season. Therefore, it is necessary to regulate and prevent the jute retting process, and its intensity and density during the monsoon to enhance biodiversity in order to ensure sustainable management and conservation of aquatic environment of the oxbow lake.
- Published
- 2015
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21. Tuning Gel State Properties of Supramolecular Gels by Functional Group Modification
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Dipankar Ghosh, Matthew T. Mulvee, and Krishna K. Damodaran
- Subjects
lmwgs ,hydrogel ,structural modification ,pyridyl amides ,n-oxides ,Organic chemistry ,QD241-441 - Abstract
The factors affecting the self-assembly process in low molecular weight gelators (LMWGs) were investigated by tuning the gelation properties of a well-known gelator N-(4-pyridyl)isonicotinamide (4PINA). The N―H∙∙∙N interactions responsible for gel formation in 4PINA were disrupted by altering the functional groups of 4PINA, which was achieved by modifying pyridyl moieties of the gelator to pyridyl N-oxides. We synthesized two mono-N-oxides (INO and PNO) and a di-N-oxide (diNO) and the gelation studies revealed selective gelation of diNO in water, but the two mono-N-oxides formed crystals. The mechanical strength and thermal stabilities of the gelators were evaluated by rheology and transition temperature (Tgel) experiments, respectively, and the analysis of the gel strength indicated that diNO formed weak gels compared to 4PINA. The SEM image of diNO xerogels showed fibrous microcrystalline networks compared to the efficient fibrous morphology in 4PINA. Single-crystal X-ray analysis of diNO gelator revealed that a hydrogen-bonded dimer interacts with adjacent dimers via C―H∙∙∙O interactions. The non-gelator with similar dimers interacted via C―H∙∙∙N interaction, which indicates the importance of specific non-bonding interactions in the formation of the gel network. The solvated forms of mono-N-oxides support the fact that these compounds prefer crystalline state rather than gelation due to the increased hydrophilic interactions. The reduced gelation ability (minimum gel concentration (MGC)) and thermal strength of diNO may be attributed to the weak intermolecular C―H∙∙∙O interaction compared to the strong and unidirectional N―H∙∙∙N interactions in 4PINA.
- Published
- 2019
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22. Stenotrophomonas maltophilia phenotypic and genotypic diversity during a 10-year colonization in the lungs of a cystic fibrosis patient
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Arianna Pompilio, Valentina Crocetta, Dipankar Ghosh, Malabika Chakrabarti, Giovanni Gherardi, Luca Vitali, Fiscarelli Ersilia, and Giovanni Di Bonaventura
- Subjects
Cystic Fibrosis ,Stenotrophomonas maltophilia ,Virulence ,Biofilm ,Chronic infection ,lung infections ,Microbiology ,QR1-502 - Abstract
The present study was carried out to understand the adaptive strategies developed by S. maltophilia for chronic colonization of the cystic fibrosis (CF) lung. For this purpose, 12 temporally isolated strains from a single CF patient chronically infected over a 10-year period were systematically characterized for growth rate, biofilm formation, motility, mutation frequencies, antibiotic resistance, and pathogenicity. Pulsed-field gel electrophoresis showed over time the presence of 2 distinct groups, each consisting of 2 different pulsotypes. The pattern of evolution followed by S. maltophilia was dependent on pulsotype considered, with strains belonging to pulsotype 1.1 resulting to be the most adapted, being significantly changed in all traits considered. Generally, S. maltophilia adaptation to CF lung leads to increased growth rate and antibiotic resistance, whereas both in vivo and in vitro pathogenicity as well as biofilm formation were decreased. Our results show for the first time that S. maltophilia can successfully adapt to a highly stressful environment such as CF lung by paying a biological cost, as suggested by the presence of relevant genotypic and phenotypic heterogeneity within bacterial population. This indicates that S. maltophilia populations are significantly more complex and dynamic than can be described by the analysis of any single isolate and can fluctuate rapidly to changing selective pressures.
- Published
- 2016
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23. Intravascular ultrasound assessment of non-culprit coronary arteries in patients suffering from ST elevation myocardial infarction
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Siddhartha Mani, Prayank Jain, Arnab Roy, Dipankar Ghosh Dastidar, and Santanu Guha
- Subjects
Surgery ,RD1-811 ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2015
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24. Impact of COVID-19 on heart failure hospitalization and outcome in India – A cardiological society of India study (CSI–HF in COVID 19 times study – “The COVID C–HF study”)
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B, Jayagopal P., S, Ramakrishnan, P, Mohanan P., A, Jabir, K, Venugopal, Das, M.K., K, Santhosh, N, Syam, Ezhilan, J., Agarwal, Rajeev, P R, Vaidyanathan, Choudhary, Ahmed Hussain, C B, Meena, Malviya, Amit, Gopi, Arun, V K, Chopra, Joseph, Stigi, Goyal, Krishna Kishore, John, John F., Bansal, Sandeep, S, Harikrishnan, Nagula, Praveen, Joseph, Johny, Bagawat, Ajit, Seth, Sandeep, Shah, Urmil, Goel, Pravin K., Asokan, P.K., Sethi, K.K., Sharma, Satyavan, Banerji, (Lt.Gen)Anup, Sikdar, Sunandan, Agarwala, ManojKumar, Chandra, Sharad, Bharti, BishwaBhushan, Ashraf, S.M., Srivastava, Smit, Kesavamoorthy, B., Bali, Harinder Kumar, Sarma, Dipak, Jain, Rajendra Kumar, Dani, Sameer I., Natesh, B.H., Chakraborty, Rabindra Nath, Gupta, Vivek, Khanna, Narendra Nath, Mukhopadhyay, Dipankar, Mandal, Subroto, Majumder, Biswajit, L, Sridhar, Girish, Meennahalli Palleda, Das, DipakRanjan, Devasia, Tom, Vajifdar, Bhavesh, Bhatia, Tanuj, Abdullah, Zia, Sharma, Sanjeev, Kumar, Sudeep, Lincy, Mathew, Naik, Nitish, Kahali, Dhiman, Sinha, Dhurjati Prasad, Dastidar, Dipankar Ghosh, Wander, Gurpreet Sing, Yadav, Rakesh, Tewari, Satyendra, Bhandari, Suman, Chandra Rath, Pratap, Bang, Vijay Harikisan, Roy, Debabrata, Banerjee, ParthoSarathi, Shanmugasundaram, S., and Zachariah, Geevar
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- 2023
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25. COVID-19 infected ST-Elevation myocardial infarction in India (COSTA INDIA)
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Jabir, Abdullakutty, Geevar Zachariah, Mohanan, Padinhare Purayil, Gupta, Mohit Dayal, Ramakrishnan, Sivasubramanian, Meena, Chandra Bhan, Sridhar, L., Girish, Meennahalli Palleda, Das, Dipak Ranjan, Gupta, Anshul, Praveen Nagula, Tom Devasia, Bhavesh Vajifdar, Kamlesh Thakkar, Urmil Shah, Tanuj Bhatia, Smit Srivastava, Sanjeev Sharma, Priya Kubendiran, Jayagopal, Pathiyil Balagopalan, Sudeep Kumar, Deepthy Sadanandan, Lincy Mathew, Nitish Naik, Anup Banerji, Ashraf, S.M., Asokan, P.K., Bharti, Bishwa Bhushan, Majumder, Biswajit, Dhiman Kahali, Sinha, Dhurjati Prasad, Sharma, Dipak, Dastidar, Dipankar Ghosh, Dipankar Mukhapdhyay, Wander, Gurpreet Sing, Bali, Harinder Kumar, Kesavamoorthy, B., Agarwala, Manoj Kumar, Khanna, Narendra Nath, Natesh, B.H., Goel, Pravin K., Chakraborty, Rabindra Nath, Jain, Rajendra Kumar, Rakesh Yadav, Sameer Dani, L., Satyavan Sharma, Satyendra Tewari, Sethi, K.K., Sharad Chandra, Mandal, Subrato, Bhandari, Suman, Sikdar, Sundandan, Vivek Gupta, Rath, Pratap Chandra, Bang, Vijay Harikisan, Debabrata Roy, Das, Mrinal Kanti, and Banerjee, Partho Sarathi
- Published
- 2023
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26. Strain echocardiography in predicting LV dysfunction in RV apical pacing
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Datta, Goutam, Dastidar, Dipankar Ghosh, and Chakraborty, Hrishikesh
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- 2023
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27. Evaluation of Risk Factors, Clinical and Angiographic Profile of Young Patients with Acute Coronary Syndrome: An Observational Study.
- Author
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MUKHOPADHYAY, TANMAY, DASTIDAR, DIPANKAR GHOSH, SARKAR, SANDIPAN, and BISWAS, UTTAM
- Subjects
- *
ACUTE coronary syndrome , *ANTERIOR wall myocardial infarction , *ANGIOGRAPHY , *MYOCARDIAL infarction , *CORONARY artery disease , *RISK assessment - Abstract
Introduction: The incidence of Acute Coronary Syndrome (ACS) in the young population has begun to rise. There is not enough data regarding the characteristics of young patients with ACS. Aim: To evaluate risk factors, clinical and angiographic profile of young patients with ACS. Materials and Methods: A prospective observational study was conducted from December 2017 to December 2020 at SSWH, Burdwan Medical College and Hospital, Burdwan, West Bengal, Kolkata, India among 100 patients. Patients with ACS and aged =45 years were enrolled in the study. Patients were divided into two groups: patients with and without obstructive Coronary Artery Disease (CAD). Clinical parameters and coronary angiography data were collected and analysed. The p-value <0.05 was considered significant. Results: The mean age of the study participants was 37.42±5.18 years, and 82 (82%) participants were male. Smoking was the most common risk factor observed in 71 (71%) of the study population, and the majority of these patients had obstructive CAD. The young population suffered more with a high incidence of ST-segment Elevation Myocardial Infarction (STEMI), with 37 (56.06%) had Anterior Wall Myocardial Infarction (AWMI). When analysed angiographically, Obstructive CAD was most commonly found 82 (82%); among those with obstructive CAD, Single-vessel diseases were predominant in 47 (47%) individuals. The percentage of stable angina was significantly higher among patients with obstructive CAD (53.6%) compared to non obstructive CAD (11.1%), (p=0.001). Conclusion: Two leading risk factors, smoking, and tobacco, were significantly associated with the onset of young ACS. The prevalence of single-vessel disease was higher in young patients with ACS compared to double and triple-vessel disease. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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28. Dynamic Response of Advanced Ceramics
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Ghatu Subhash, Amnaya Awasthi, Dipankar Ghosh
- Published
- 2021
29. STUDY OF VITAMIN B12 DEFICIENCY IN TYPE 2 DIABETES MELLITUS AND ITS CORRELATION WITH PERIPHERAL NEUROPATHY.
- Author
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Jha, Bijay Narayan, Dastidar, Dipankar Ghosh, and K., Arun Kumar
- Subjects
- *
VITAMIN B12 deficiency , *TYPE 2 diabetes , *PERIPHERAL neuropathy , *VITAMIN B deficiency , *VITAMIN B12 - Abstract
Aim: The aim of the present study was to assess the deficiency of vitamin B12 in the patients of type 2 diabetes mellitus with peripheral neuropathy and its correlation. Methods: The participants for the present study were recruited from patients with T2DM seen in the South Eastern Railway Central Hospital, Kolkata. The study was conducted for two years. Results: Patients with diabetic neuropathy were older as majority had age between 61-70 years (55.40%) compared to those without neuropathy (majority had age between 51-60 years; 39.80%). The sex distribution between group was significantly different as revealed by the highly significant p value of <0.001. 9.60% of the patients with diabetes neuropathy had vitamin B 12 deficiency compared to control group (1.20%). Diabetes neuropathy patients had mean Vitamin B12 (471.33±168.992), diabetes with no neuropathy patients (479.11±208.121). Subjects in control group had higher Vitamin B12 level compared to remaining two groups. Conclusion: Vitamin B12 deficiency is highly prevalent, especially in patients with diabetic neuropathy. In this study an inverse correlation was found between diabetic neuropathy and the plasma level of vitamin B12. The association between diabetic neuropathy and Vitamin B12 deficiency is of great importance, since diabetic or prediabetic patients diagnosed with diabetic neuropathy may have neuropathy due to vitamin B12 deficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2023
30. An Outcome Analysis of Asymptomatic COVID-19 Patients Presenting with Angina- A Retrospective Study.
- Author
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DASTIDAR, DIPANKAR GHOSH, SANYAL, RAKHI, DASTIDAR, NANDITA GHOSH, and HALDER, TIRNA
- Subjects
- *
ASYMPTOMATIC patients , *COVID-19 , *ST elevation myocardial infarction , *COVID-19 pandemic , *CARDIOVASCULAR diseases , *CORONAVIRUS diseases - Abstract
Introduction: Cardiovascular disorders have long been considered as one of the leading causes of mortality in India, which when presented with concurrent Coronavirus Disease (COVID-19) infection becomes even more fatal. Evidence suggests that COVID-19 affects the cardiovascular system by causing exuberant cytokinaemia, which results in endothelial inflammation and microvascular thrombosis, leading to multiorgan failure. Aim: To analyse the outcome of the asymptomatic COVID-19 patients presenting with cardiac angina during the second wave of COVID-19 in India. Materials and Methods: This is a retrospective data analysis of asymptomatic COVID-19 patients hospitalised with angina was conducted between April 2021 to June 2021 at Bardhhaman Medical College and Hospital located at Bardhdhaman district of West Bengal, India. A total of 1235 patients underwent all regular biochemical, haematological and cardiac investigations after undergoing test for COVID-19 test. Data was retrospectively collected. The outcome of these patients was analysed. Estimation of mean, standard deviation, percentage, p-value (from Pearson's correlation) was performed to establish the aim of the study. Results: Seventy six out of 1235 patients tested positive for asymptomatic COVID-19. The mean age of this study population was 55.075±10.95 years, of which were 55 male and 21 female. Hypertension was the most prevalent co-morbidity followed by diabetes, 73 (96%) presented with chest pain. A total of 47(62%) of these 76 patients had ST Elevated Myocardial Infarction (STEMI). Eleven (14.4%) underwent Percutaneous Coronary Intervention (PCI) whereas 36 (47.3%) underwent fibrinolytic therapy with tenecteplase, followed by secondary PCI in 27 (75%) of them. Rest 29 (38%) were medically managed for unstable angina. Mortality rate was as low as 6.5%. Age and comorbidity were the contributing factors for STEMI among asymptomatic COVID-19 patients. Conclusion: The results indicate that age and comorbidity are the factors, which lead to death or increases the life risk among patients with asymptomatic COVID-19. In this study, we have established that for the current patient population STEMI and age are negatively corelated. Medical management with thrombolytic agent became a lot more accepted in this scenario. PCI still remains the gold standard to treat myocardial infarction. It is recommended that there should be an ICMR guided protocol for the management of such cases with the concurrent COVID-19. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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31. An evidenced-based critical discussion to demonstrate leadership and management approaches
- Author
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Dr. Dipankar Ghosh
- Published
- 2022
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32. Comparative Assessment of The Difference Between Men and Women Hospitalized for ACS During COVID-19 PANDEMIC.
- Author
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Dastidar, Dipankar Ghosh, Kamat, Ramdhan Kumar, and Mondal, Koushik
- Subjects
- *
COVID-19 pandemic , *HEART valve diseases , *CONGENITAL heart disease , *ACUTE coronary syndrome , *ANGINA pectoris - Abstract
Aim: We assessed whether women were more affected by the dramatic drop in hospital admissions for ACS during the Covid-19 pandemic. Methods: This evaluation is an Institutional Review Board (IRB) exempt retrospective, observational study performed inBurdwan Medical College, Burdwan, West Bengal, India. We performed chart review of 1000 patients who presented to Burdwan Medical College, Burdwan, West Bengal, India Catheterization lab for elective and emergency catheterization for non ACS and ACS [NSTEMI, Unstable angina (UA), STEMI] during a 4-week period from February 26 to March 10 and from March 25 to April 8 and compared with the equivalent weeks in the last year. Results: Out of 1000, only 450 patients underwent cardiac catheterization for acute coronary syndrome. Remaining patients underwent cardiac catheterization for causes other than acute coronary syndrome, such as atrial septal defect closure, pulmonary arterial hypertension to assess hemodynamics in the heart chambers, cardiac myxoma, treatment of valvular heart disease (e.g., transcatheter mitral valve repair), assessment of the congenital heart diseases like cor triatriatum. Conclusion: In conclusion, the pandemic period reduced the gap between men and women in ACS: the extraordinary reduction in admission rates observed during the Covid-19 pandemic seems to have strongly affected women as men, with similar rates of reduction of hospitalized STEMI and NSTEMI and a trend toward greater reduction in UA admission among women. [ABSTRACT FROM AUTHOR]
- Published
- 2022
33. A HOSPITAL BASED OBSERVATIONAL EVALUATION OF EVALUATE ST ELEVATION MYOCARDIAL INFARCTION OF INFERIOR WALL AND RIGHT VENTRICLE IN RHEUMATIC MITRAL STENOSIS DUE TO THROMBUS AT RIGHT CORONARY SINUS.
- Author
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Dastidar, Dipankar Ghosh, Kamat, Ramdhan Kumar, and Mondal, Koushik
- Subjects
- *
INFERIOR wall myocardial infarction , *MYOCARDIAL infarction , *MITRAL stenosis , *CORONARY artery disease , *THROMBOSIS - Abstract
Aim: The aim of the present study was to evaluate ST elevation myocardial infarction of inferior wall and right ventricle in rheumatic mitral stenosis due to thrombus at right coronary sinus. Methods: The present study was conducted in the Department of cardiology, Burdwan medical college and hospital, West Bengal, India. Acute MI was diagnosed by the presence of at least 2 of the following criteria: electrocardiographic changes, significant rises in myocardial bound creatine kinase fraction, and typical chest pain. Inferior wall MI was diagnosed by electrocardiography, echocardiography and coronary angiography. In patients with non-ST elevation MI, echocardiography and coronary angiographic findings were used for determination of the diagnosis of inferior wall MI. There was total 100 patients included in the present study. Results: Echocardiography was performed within 1.7±1.4 days (range 0-5) after acute MI. There were no differences in age, sex and other frequencies of underlying diseases among the 3 groups. There were no differences in the modality of intervention, severity of coronary artery disease. Fifty-five (73.34%) patients had the culprit lesion in the right coronary artery and 20 (26.6%) patients had the culprit lesion in the left circumflex artery. Patients whose culprit lesion in the left circumflex artery had an increased frequency of more severe MR than those with the culprit lesion in the right coronary artery, but this difference did not reach statistical significance (P=0.420). Conclusion: In the acute phase of inferior wall MI, MR was associated with LV systolic dysfunction with tethering. Therefore, it can be suggested that reduced closing force as a consequence of LV systolic dysfunction in the presence of leaflet tethering would play a more pivotal role in the development of MR in the acute phase of inferior MI, whereas increased tethering forces through a combination of annular dilation and geometric remodeling of the LV would be more important contributor in the chronic phase. [ABSTRACT FROM AUTHOR]
- Published
- 2022
34. Enantioselective Gel Phase Synthesis of Metal–Organic Materials
- Author
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Marcin Górecki, Dipankar Ghosh, Krishna K. Damodaran, and Gennaro Pescitelli
- Subjects
supramolecular gel phase synthesis ,Chemistry ,Enantioselective synthesis ,General Chemistry ,General Medicine ,Combinatorial chemistry ,Solution phase ,Catalysis ,Phase synthesis ,Metal ,solid-state CD ,metal-organic materials ,visual_art ,visual_art.visual_art_medium ,enantioselective synthesis ,Chirality (chemistry) ,chiral induction ,Chiral induction - Abstract
We report the asymmetric synthesis of homochiral metal-organic materials (MOMs) in chiral gels from achiral components. The enantioselectivity of MOMs depends on the chirality of the gel, whereas the synthesis performed in solution phase and achiral gels resulted in conglomerates.
- Published
- 2021
35. Advances in Powder and Ceramic Materials Science 2023
- Author
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Bowen Li, Dipankar Ghosh, Eugene A. Olevsky, Kathy Lu, Faqin Dong, Jinhong Li, Ruigang Wang, Alexander D. Dupuy, Elisa Torresani, Bowen Li, Dipankar Ghosh, Eugene A. Olevsky, Kathy Lu, Faqin Dong, Jinhong Li, Ruigang Wang, Alexander D. Dupuy, and Elisa Torresani
- Subjects
- Ceramic materials, Composite materials, Metals, Building materials, Materials science
- Abstract
This collection emphasizes the advances of powder and ceramic/glass materials in the fundamental research, technology development, and industrial applications. Ceramic materials science covers the science and technology of creating objects from inorganic, non-metallic materials, and includes design, synthesis, and fabrication of ceramics, glasses, advanced concretes, and ceramic-metal composites. In recent years, the hybrids of ceramic and metallic materials have received plenty of interdisciplinary inspirations and achievements in material processes and functional applications including ionic conductors, catalysis, energy conversion and storage, superconductors, semiconductor, filtrations, etc. Topics cover, but are not limited to:· Silicates, oxides, and non-oxide ceramics and glasses · Synthesis, characterization, modeling, and simulation of ceramic materials · Design and control of ceramic microstructure and properties · Ceramic powders and processing · Catalyst and catalyst support materials · Fundamental understanding of ceramic materials and processes · Novel methods, techniques, and instruments used to characterize ceramics and glasses · High entropy ceramics (and/or entropy stabilized, complex-concentrated, compositionally-complex, multi-principal cation ceramics) · Bioceramics, electronic, magnetic ceramics, and applications · Surface treatment and ceramic thin films, membranes, and coatings · Porous ceramic materials · Hybrid systems of ceramic, metal, and/or polymer composites · Ceramics used for extreme environments · Metallurgical byproducts for ceramic manufacturing
- Published
- 2023
36. Tuning Gel State Properties of Supramolecular Gels by Functional Group Modification
- Author
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Matthew T. Mulvee, Dipankar Ghosh, Krishna K. Damodaran, Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, and University of Iceland
- Subjects
Models, Molecular ,Dimer ,Molecular Conformation ,Supramolecular chemistry ,Pharmaceutical Science ,Phase Transition ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Rheology ,Efnafræði ,Drug Discovery ,LMWGs ,Pyridyl amides ,Isonicotinamide ,Physical and Theoretical Chemistry ,structural modification ,N-oxides ,Molecular Structure ,Spectrum Analysis ,Transition temperature ,Organic Chemistry ,Intermolecular force ,Temperature ,Hydrogels ,Hydrogen Bonding ,Molecular Weight ,pyridyl amides ,Crystallography ,Hydrogel ,Microcrystalline ,chemistry ,Chemistry (miscellaneous) ,Structural modification ,Functional group ,Solvents ,Molecular Medicine ,hydrogel ,Gels - Abstract
Publisher's version (útgefin grein), The factors affecting the self-assembly process in low molecular weight gelators (LMWGs) were investigated by tuning the gelation properties of a well-known gelator N-(4-pyridyl)isonicotinamide (4PINA). The N—H···N interactions responsible for gel formation in 4PINA were disrupted by altering the functional groups of 4PINA, which was achieved by modifying pyridyl moieties of the gelator to pyridyl N-oxides. We synthesized two mono-N-oxides (INO and PNO) and a di-N-oxide (diNO) and the gelation studies revealed selective gelation of diNO in water, but the two mono-N-oxides formed crystals. The mechanical strength and thermal stabilities of the gelators were evaluated by rheology and transition temperature (Tgel) experiments, respectively, and the analysis of the gel strength indicated that diNO formed weak gels compared to 4PINA. The SEM image of diNO xerogels showed fibrous microcrystalline networks compared to the efficient fibrous morphology in 4PINA. Single-crystal X-ray analysis of diNO gelator revealed that a hydrogen-bonded dimer interacts with adjacent dimers via C—H···O interactions. The non-gelator with similar dimers interacted via C—H···N interaction, which indicates the importance of specific non-bonding interactions in the formation of the gel network. The solvated forms of mono-N-oxides support the fact that these compounds prefer crystalline state rather than gelation due to the increased hydrophilic interactions. The reduced gelation ability (minimum gel concentration (MGC)) and thermal strength of diNO may be attributed to the weak intermolecular C—H···O interaction compared to the strong and unidirectional N—H···N interactions in 4PINA., We thank the University of Iceland Research Fund and the Science Institute for funding. D.G. thanks the University of Iceland for the Doctoral Research and Teaching Assistantship grant. We thankfully acknowledge Jonathan Steed, Durham University, Durham, UK for rheology experiments, Sigurjur Sveinn Jonsson, ISOR-Iceland for X-ray powder diffraction analysis, and Sigridur Jonsdottir, University of Iceland for NMR and mass spectroscopy. We thank Rannís Iceland for granting an infrastructure grant for a single-crystal X-ray diffractometer.
- Published
- 2019
- Full Text
- View/download PDF
37. The (ir)regularity of Tor and Ext
- Author
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Dipankar Ghosh, Marc Chardin, and Navid Nemati
- Subjects
Pure mathematics ,13D07, 13D02 ,Dimension (vector space) ,Degree (graph theory) ,Mathematics::Commutative Algebra ,Mathematics::K-Theory and Homology ,Applied Mathematics ,General Mathematics ,Complete intersection ,Linearity ,Mathematics - Commutative Algebra ,Mathematics::Algebraic Topology ,Mathematics - Abstract
We investigate the asymptotic behaviour of Castelnuovo-Mumford regularity of Ext and Tor, with respect to the homological degree, over complete intersection rings. We derive from a theorem of Gulliksen a linearity result for the regularity of Ext modules in high homological degrees. We show a similar result for Tor, under the additional hypothesis that high enough Tor modules are supported in dimension at most one; we then provide examples showing that the behaviour could be pretty hectic when the latter condition is not satisfied., Comment: 24 pages, updated version
- Published
- 2019
38. A fractional order SITR mathematical model for forecasting of transmission of COVID-19 of India with lockdown effect
- Author
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Dipankar Ghosh, Abdelalim A. Elsadany, Sameh S. Askar, P. K. Santra, and G. S. Mahapatra
- Subjects
Differential equation ,Reproduction number ,QC1-999 ,SITR compartmental model ,General Physics and Astronomy ,02 engineering and technology ,01 natural sciences ,Stability (probability) ,Refuge ,Article ,Exponential stability ,0103 physical sciences ,Lockdown ,Applied mathematics ,Sensitivity (control systems) ,Uniqueness ,Mathematics ,010302 applied physics ,Equilibrium point ,Physics ,COVID-19 ,021001 nanoscience & nanotechnology ,Fractional differential equation ,Transmission (telecommunications) ,0210 nano-technology ,Basic reproduction number ,Stability - Abstract
In this paper, we consider a mathematical model to explain, understanding, and to forecast the outbreaks of COVID-19 in India. The model has four components leading to a system of fractional order differential equations incorporating the refuge concept to study the lockdown effect in controlling COVID-19 spread in India. We investigate the model using the concept of Caputo fractional-order derivative. The goal of this model is to estimate the number of total infected, active cases, deaths, as well as recoveries from COVID-19 to control or minimize the above issues in India. The existence, uniqueness, non-negativity, and boundedness of the solutions are established. In addition, the local and global asymptotic stability of the equilibrium points of the fractional-order system and the basic reproduction number are studied for understanding and prediction of the transmission of COVID-19 in India. The next step is to carry out sensitivity analysis to find out which parameter is the most dominant to affect the disease’s endemicity. The results reveal that the parameters η , μ and ρ are the most dominant sensitivity indices towards the basic reproductive number. A numerical illustration is presented via computer simulations using MATLAB to show a realistic point of view.
- Published
- 2021
39. Vanishing of (co)homology over deformations of Cohen-Macaulay local rings of minimal multiplicity
- Author
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Dipankar Ghosh and Tony J. Puthenpurakal
- Subjects
Hilbert's syzygy theorem ,Mathematics::Commutative Algebra ,General Mathematics ,010102 general mathematics ,Local ring ,Multiplicity (mathematics) ,Homology (mathematics) ,Commutative Algebra (math.AC) ,Mathematics - Commutative Algebra ,01 natural sciences ,Combinatorics ,Residue field ,0103 physical sciences ,FOS: Mathematics ,010307 mathematical physics ,0101 mathematics ,Primary 13D07, Secondary 13D02, 13H05, 13H10 ,Mathematics - Abstract
Let $ R $ be a $ d $-dimensional Cohen-Macaulay (CM) local ring of minimal multiplicity. Set $ S := R/({\bf f}) $, where $ {\bf f} := f_1,\ldots,f_c $ is an $ R $-regular sequence. Suppose $ M $ and $ N $ are maximal CM $ S $-modules. It is shown that if $ \mathrm{Ext}_S^i(M,N) = 0 $ for some $ (d+c+1) $ consecutive values of $ i \geqslant 2 $, then $ \mathrm{Ext}_S^i(M,N) = 0 $ for all $ i \geqslant 1 $. Moreover, if this holds true, then either $ \mathrm{projdim}_R(M) $ or $ \mathrm{injdim}_R(N) $ is finite. In addition, a counterpart of this result for Tor-modules is provided. Furthermore, we give a number of necessary and sufficient conditions for a CM local ring of minimal multiplicity to be regular or Gorenstein. These conditions are based on vanishing of certain Exts or Tors involving homomorphic images of syzygy modules of the residue field., 20 pages, Final version after revision, To appear in Glasgow Mathematical Journal
- Published
- 2017
40. Plastic Work to Heat Conversion During High-Strain Rate Deformation of Mg and Mg Alloy
- Author
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Guruswami Ravichandran, Dipankar Ghosh, and Owen T. Kingstedt
- Subjects
010302 applied physics ,Work (thermodynamics) ,Materials science ,Structural material ,Magnesium ,Alloy ,Metallurgy ,Metals and Alloys ,technology, industry, and agriculture ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,equipment and supplies ,01 natural sciences ,Grain size ,chemistry ,Mechanics of Materials ,0103 physical sciences ,engineering ,Magnesium alloy ,Deformation (engineering) ,0210 nano-technology ,Bar (unit) - Abstract
Magnesium and magnesium alloy were investigated for plastic work to heat conversion (β). Thermomechanical response was measured employing the shear-compression specimen geometry, a split-Hopkinson pressure bar, and an infra-red detector. β of both materials measured to be less than the common assumption of 0.9; however, heat conversion was observed to be greater for magnesium alloy. Thus, results suggest that alloying and grain size refinement not only improved yield strength but also affected the thermomechanical response.
- Published
- 2017
41. Some criteria for regular and Gorenstein local rings via syzygy modules
- Author
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Dipankar Ghosh
- Subjects
Pure mathematics ,Algebra and Number Theory ,Hilbert's syzygy theorem ,Mathematics::Commutative Algebra ,Applied Mathematics ,Astrophysics::Instrumentation and Methods for Astrophysics ,Local ring ,Computer Science::Computation and Language (Computational Linguistics and Natural Language and Speech Processing) ,Commutative Algebra (math.AC) ,Mathematics - Commutative Algebra ,13D02, 13D07, 13H05, 13H10 ,FOS: Mathematics ,Computer Science::General Literature ,Mathematics - Abstract
Let $ R $ be a Cohen-Macaulay local ring. We prove that the $ n $th syzygy module of a maximal Cohen-Macaulay $ R $-module cannot have a semidualizing direct summand for every $ n \ge 1 $. In particular, it follows that $ R $ is Gorenstein if and only if some syzygy of a canonical module of $ R $ has a non-zero free direct summand. We also give a number of necessary and sufficient conditions for a Cohen-Macaulay local ring of minimal multiplicity to be regular or Gorenstein. These criteria are based on vanishing of certain Exts or Tors involving syzygy modules of the residue field., 13 pages
- Published
- 2016
42. Characterizations of regular local rings via syzygy modules of the residue field
- Author
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Dipankar Ghosh, Anjan Gupta, and Tony J. Puthenpurakal
- Subjects
Noetherian ,Pure mathematics ,Hilbert's syzygy theorem ,13D02 ,Mathematics::Commutative Algebra ,Direct sum ,semi-dualizing modules ,13D05 ,Local ring ,Commutative Algebra (math.AC) ,Mathematics - Commutative Algebra ,Injective function ,syzygy and cosyzygy modules ,semidualizing modules ,Residue field ,injective dimension ,FOS: Mathematics ,13H05 ,Primary 13D02, Secondary 13D05, 13H05 ,Commutative property ,Regular local rings ,Mathematics - Abstract
Let $R$ be a commutative Noetherian local ring with residue field $k$. We show that if a finite direct sum of syzygy modules of $k$ surjects onto `a semidualizing module' or `a non-zero maximal Cohen-Macaulay module of finite injective dimension', then $R$ is regular. We also prove that $R$ is regular if and only if some syzygy module of $k$ has a non-zero direct summand of finite injective dimension., 7 pages
- Published
- 2015
43. Length of Lambda -nin 5 DNA
- Author
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Dipankar Ghosh and Anima Dhar
- Subjects
lcsh:Q ,lcsh:Science - Abstract
Length of Lambda -nin 5 DNA
- Published
- 2015
44. Domain Wall Displacement is the Origin of Superior Permittivity and Piezoelectricity in BaTiO_3 at Intermediate Grain Sizes
- Author
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Juan C. Nino, Jacob L. Jones, Jared Carter, Pam A. Thomas, Dipankar Ghosh, HyukSu Han, and Akito Sakata
- Subjects
Permittivity ,Materials science ,Condensed matter physics ,Dielectric ,Condensed Matter Physics ,Ferroelectricity ,Piezoelectricity ,Grain size ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Crystallography ,chemistry.chemical_compound ,Domain wall (magnetism) ,chemistry ,TA ,Electric field ,Barium titanate ,Electrochemistry ,QC - Abstract
The dielectric and piezoelectric properties of ferroelectric polycrystalline materials have long been known to be strong functions of grain size and extrinsic effects such as domain wall motion. In BaTiO_3, for example, it has been observed for several decades that the piezoelectric and dielectric properties are maximized at intermediate grain sizes (≈1 μm) and different theoretical models have been introduced to describe the physical origin of this effect. Here, using in situ, high-energy X-ray diffraction during application of electric fields, it is shown that 90° domain wall motion during both strong (above coercive) and weak (below coercive) electric fields is greatest at these intermediate grain sizes, correlating with the enhanced permittivity and piezoelectric properties observed in BaTiO_3. This result validates the long-standing theory in attributing the size effects in polycrystalline BaTiO_3 to domain wall displacement. It is now empirically established that a doubling or more in the piezoelectric and dielectric properties of polycrystalline ferroelectric materials can be achieved through domain wall displacement effects; such mechanisms are suggested for use in the design of new ferroelectric materials with enhanced properties.
- Published
- 2014
45. Human defensin 5 expression in intestinal metaplasia of the upper gastrointestinal tract
- Author
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C Shen, Bo Shen, Tomas Ganz, Terry Gramlich, E Reynoso, Charles L. Bevins, M S Sy, R Li, Jason T. Connor, Edith Porter, H K Rho, Dipankar Ghosh, Adrian H. Ormsby, and Judith A. Drazba
- Subjects
Adult ,Male ,medicine.medical_specialty ,Pathology ,Paneth Cells ,Blotting, Western ,education ,Gene Expression ,Enzyme-Linked Immunosorbent Assay ,Biology ,digestive system ,Pathology and Forensic Medicine ,Helicobacter Infections ,Defensins ,Barrett Esophagus ,Metaplasia ,medicine ,Humans ,RNA, Messenger ,Defensin ,Aged ,Helicobacter pylori ,Reverse Transcriptase Polymerase Chain Reaction ,digestive, oral, and skin physiology ,Intestinal metaplasia ,Histology ,Anatomical pathology ,General Medicine ,Original Articles ,Middle Aged ,medicine.disease ,biology.organism_classification ,Small intestine ,digestive system diseases ,humanities ,medicine.anatomical_structure ,Gastric Mucosa ,Immunohistochemistry ,Female ,Esophagogastric Junction ,medicine.symptom - Abstract
Background: Upper gastrointestinal tract intestinal metaplasia (IM) is termed Barrett’s oesophagus (BO) or gastric intestinal metaplasia (GIM), depending on its location. BO and GIM are associated with chemical exposure resulting from gastro–oesophageal reflux and chronic Helicobacter pylori infection, respectively. Paneth cells (PCs), characterised by cytoplasmic eosinophilic granules, are found in a subset of IM at these sites, but histology may not accurately detect them. Aim: To determine human defensin 5 (HD5; an antimicrobial peptide produced by PCs) expression in BO and GIM, and to investigate its association with H pylori infection. Methods: Endoscopic biopsies from 33 patients with BO and 51 with GIM, and control tissues, were examined by routine histology and for H pylori infection and HD5 mRNA and protein expression. Results: In normal tissues, HD5 expression was specific for PCs in the small intestine. Five patients with BE and 42 with GIM expressed HD5, but few HD5 expressing cells in IM had the characteristic histological features of PCs. Most HD5 positive specimens were H pylori infected and most HD5 negative specimens were not infected. Conclusions: HD5 immunohistochemistry was often positive in IM when PCs were absent by conventional histology. Thus, HD5 immunohistochemistry may be superior to histology for identifying metaplastic PCs and distinguishing GIM from BO. The higher frequency of HD5 expression in GIM than in BO is associated with a higher frequency of H pylori infection, suggesting that in IM PCs may form part of the mucosal antibacterial response.
- Published
- 2005
46. Microencapsulation of bovine serum albumin by solvent evaporation and in situ polymerization techniques
- Author
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Partba Sarathi Pal, Dipankar Ghosh, Debanjan Sarkar, Narayan Mukherjee, and Priyabrata Sarkar
- Subjects
polymerization ,techniques ,solvent - Abstract
Department of Polymer Science and Technology, University of Calcutta, Kolkata-700 009, India E-mail : psarkar@cubmb.ernet.in Fax : 91-33-4852976 Manuscript received 28 June 2001, accepted 5 November 2001 This paper presents two techniques for microencapsulation of bovine serum albumin (BSA), namely, solvent evaporation and in situ polymerization. Both these processes have been designed to give improved loading and release rates. We achieved high encapsulation efficiency with high microcapsule yield using high power ultrasonication for formation of microemulsion and an efficient microsprayer for the formation of double emulsion. In situ polymerization in the organic (methyl methacrylate, MMA) liquid membrane of the microemulsion was conducted in inert atmosphere. Both the methods are cost-effective and may be designed for predetermined release of the biomaterials.
- Published
- 2002
- Full Text
- View/download PDF
47. Intellectual capital and capital markets: additional evidence.
- Author
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Dipankar Ghosh and Anne Wu
- Subjects
- *
INTELLECTUAL capital , *CAPITAL market , *CORPORATE finance , *INVESTMENTS , *TIME series analysis , *FINANCIAL performance - Abstract
Purpose - The purpose of this paper is to first examine whether intellectual capital (IC) information is considered in firm valuation. Next, to examine two issues: financial analysts'' investment recommendations when faced with different combinations of performance levels (i.e. above or below industry average) of financial and IC measures, and the role of financial and IC measures with different performance levels and holding periods (i.e. short-term vs long-term) for the investment on analysts'' recommendations. Design/methodology/approach - The first part of the paper used secondary (both archival and survey) data. The second part was an experiment. Findings - The findings in the first part show that, after controlling for the effect of financial performances on firm value, measures of IC are still significant explanatory variables (of firm value). The second part shows that the financial and IC measures affect financial analysts'' investment recommendations differently depending on the measures'' levels of performance and the time horizon for holding the investments. Research limitations/implications - The limitations of the paper are as follows: the use of secondary data from a single country limits its generalizability; and the results of the experiment are parameterized by the research design such as the amount of information provided to the financial analysts. Extending the analyses to other settings and using time-series data represent future research opportunities. Originality/value - The research makes three contributions to the IC literature. First, it extends the studies on the relevance of IC in capital market research by broadening its scope to include measures of IC other than R&D intensity. Next, it provides evidence of the informativeness of IC measures in market valuation of firms and analysts'' recommendations, thus lending credence to the arguments of reports and researchers for more external communication of IC information. Finally, this study is one of the first to examine a broader scope of IC in the capital market context and the use of IC by sophisticated market participants. With policy-makers and standard-setting bodies considering proposals to enhance information on IC in financial reports, it is important to broaden the scope of IC metrics and understand their role in enhancing firm value to develop a framework for reporting IC. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
48. Determination of six anti-infectives in wastewater using tandem solid-phase extraction and liquid chromatography–tandem mass spectrometry.
- Author
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Pedro A. Segura, Araceli García-Ac, André Lajeunesse, Dipankar Ghosh, Christian Gagnon, and Sébastien Sauvé
- Abstract
A rugged and specific method based on tandem solid-phase extraction and liquid chromatography–tandem mass spectrometry for the determination of anti-infectives in raw sewage and wastewater plant effluents was developed. Analyte recoveries from spiked effluents ranged from 68 to 104%. Two specific selected reaction monitoring transitions and their peak area ratios were used to avoid false positives and confirm the presence of the targeted substances. Detection limits allowed low nanogram per litre detection (0.3–22 ng L−1). The method was successfully applied to real samples from the Montréal wastewater treatment plant. All the studied anti-infectives were found in the wastewater samples in concentrations ranging from 39 to 276 ng L−1. Mean flows of anti-infectives were estimated from effluent concentrations and it was found that large amounts (>118 g day−1 up to 830 g day−1) are discharged in the receiving waters of the St Lawrence River. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
49. Extraction and Monitoring of Phytoecdysteroids Through HPLC.
- Author
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Dipankar Ghosh and K.S. Laddha
- Abstract
The size of the phytoecdysteroids family is rapidly growing. Recent data shows over 250 ecdysteroid analogs have been identified so far in plants. It is theorized that there are over 1000 possible structures, which might occur in nature, but it is a fact that ecdysteroids usually occur in plants as a complex cocktail of structurally different compounds. Among these compounds, the major component is usually the common ecdysteroid-like 20-hydroxyecdysone. Ecdysteroids are polar steroids, almost sugar-like in their solubility properties. Extraction and purification of ecdysteroids (polyhydroxy steroids) is complicated by their polar nature and poor crystallizing properties. These properties make them difficult to separate from other polar plant constituents. Besides, this plant extract is very often processed by multistep procedures to isolate the major and minor ecdysteroids from the new or existing sources. A simplified scheme consisting of a few extraction steps for the purification of ecdysteroid from plants is in great demand. A quantitative approach through high-performance liquid chromatography has been initiated for developing an easy method for the extraction of ecdysteroids from Ipomoea hederacea (kaladana) seeds. [ABSTRACT FROM AUTHOR]
- Published
- 2006
50. Risk Attitude, Ambiguity Intolerance and Decision Making: An Exploratory Investigation.
- Author
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Dipankar Ghosh and Ray, Manash R.
- Subjects
DECISION making ,RESEARCH ,ATTITUDES toward work ,INDUSTRIAL psychology ,BEHAVIOR ,RISK management in business - Abstract
Although recent research has identified attitudes towards ambiguity and risk to be important determinants of choice behavior, no prior work jointly assessed the roles of both attitudes. We conducted a laboratory experiment using a real decision scenario and conducted exploratory analyses of the relationship between attitudes towards risk and ambiguity and the decision taken by the subjects. The results support the prediction that attitudes towards both risk and ambiguity affect choice behavior. Our exploratory analyses indicate interesting avenues for future research, including an examination of the decision process itself. [ABSTRACT FROM AUTHOR]
- Published
- 1992
- Full Text
- View/download PDF
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