21 research outputs found
Role of Ionic Liquid in Asphaltene Dissolution: A Combined Experimental and Molecular Dynamics Study
No full textThe role of ionic liquid in asphaltene dissolution is studied using experimental characterization techniques, such as optical microscopic imaging analysis, 13C nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy, along with molecular insights achieved using classical molecular dynamics (MD) simulations. The dissolution behavior of the asphaltenes in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid along with organic solvents, i.e., toluene and hexane, is investigated using optical images. The behavior of asphaltene aggregates in the solvent plus ionic liquid mixture is probed using FTIR and 13C NMR spectroscopic techniques. The structural and dynamical properties of the asphaltene aggregates mainly end-to-end distance, the diffusion coefficient of the asphaltene molecules, and the trajectory density contour of the asphaltene in the solvent plus ionic liquid mixture are probed using MD simulations. It is concluded from our combined experimental-MD study that the ionic liquid plays a key role in asphaltene separation from organic solvents under study.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Poulumi De
Autonomous MEMS- Based Intracellular Neural Interfaces
No full textabstract: Intracellular voltage recordings from single neurons in vitro and in vivo have been fundamental to our understanding of neuronal function. Conventional electrodes and associated positioning systems for intracellular recording in vivo are large and bulky, which has largely restricted their use to single-channel recording from anesthetized animals. Further, intracellular recordings are very cumbersome, requiring a high degree of skill not readily achieved in a typical laboratory. This dissertation presents a robotic, head-mountable, MEMS (Micro-Electro-Mechanical Systems) based intracellular recording system to overcome the above limitations associated with form-factor, scalability and highly skilled and tedious manual operations required for intracellular recordings. This system combines three distinct technologies: 1) novel microscale, polycrystalline silicon-based electrode for intracellular recording, 2) electrothermal microactuators for precise microscale navigation of the electrode and 3) closed-loop control algorithm for autonomous movement and positioning of electrode inside single neurons. First, two distinct designs of polysilicon-based microscale electrodes were fabricated and tested for intracellular recordings. In the first approach, tips of polysilicon microelectrodes were milled to nanoscale dimensions (1.5 mV amplitude, positive-going action potentials and synaptic potentials from neurons in the abdominal ganglion of Aplysia Californica. In the second approach, polysilicon microelectrodes were integrated with miniaturized glass micropipettes filled with electrolyte to fabricate glass-polysilicon microelectrodes. These electrodes consistently recorded high fidelity intracellular potentials from neurons in the abdominal ganglion of Aplysia Californica (Resting Potentials 60 mV) as well as the rat motor cortex (Resting Potentials 60 mV) were recorded after each successful penetration attempt with the controller and microactuated glass-polysilicon microelectrodes. The success rate of penetration and quality of recordings achieved using electrothermal microactuators were comparable to that of conventional positioning systems. Finally, the feasibility of this miniaturized system to obtain intracellular recordings from single neurons in the motor cortex of rats in vivo is also demonstrated. The MEMS-based system offers significant advantages: 1) reduction in overall size for potential use in behaving animals, 2) scalable approach to potentially realize multi-channel recordings and 3) a viable method to fully automate measurement of intracellular recordings.Dissertation/ThesisDoctoral Dissertation Biomedical Engineering 201
Deep eutectic solvents interaction with asphaltenes: A combined experimental and molecular dynamics study
No full textDeep eutectic solvents (DESs) are industrially promising solvents and posses numerous applications in wide areas such as metal processing, synthesis media, synthesis of nanoparticles, gas sequestration and many more. In this work, we synthesized and investigated the performance of three deep eutectic solvents (DESs) i.e., reline, glyceline and ethaline in the separation of pure asphaltene from organic solvents, i.e., toluene and n-heptane using experimental techniques and classical molecular dynamics (MD) simulations. The DESs are prepared and characterized by Fourier transform infrared (FTIR) spectroscopy and density meter analysis. The separation and aggregation of asphaltene from the organic solvent phase into the DES phase at various DES concentrations are visually observed using optical microscopy. MD simulations are used to probe the end-to-end distance and diffusion coefficient of the asphaltene molecules in DESs-organic solvent mixtures. Further, the trajectory density contours of asphaltene in three DESs-toluene/n-heptane systems are calculated to analyze asphaltene aggregation in the presence of the DESs. Our experimental-simulations synergistic study shows the superior performance of glyceline DES in toluene and reline DES in n-heptane for efficient separation of the asphaltene.Team Poulumi De
Mantle cell lymphoma presenting as acute appendicitis
No full textAbstractINTRODUCTIONMost cases of appendicitis associated with lymphoma reported in literature are in patients with Burkitt's or large B-cell lymphoma. Mantle cell lymphoma only makes up 4% of all lymphoma cases in the U.S. We report a case of a patient with mantle cell lymphoma presenting with acute appendicitis.PRESENTATION OF CASEA 75 year old male with a history of left cervical lymphadenopathy biopsied to be mantle cell lymphoma presented with right lower abdomen pain for 3 days. An outpatient CT scan revealed acute appendicitis. Laparoscopic appendectomy was performed without any complication. The histologic examination showed mantle cell lymphoma occluding the lumen of appendix.DISCUSSIONTypically, appendicitis is caused by obstruction of the lumen of appendix by fecalith or lymphoma. A previously reported case of a patient with mantle cell lymphoma who developed appendicitis received chemotherapy before appendectomy. The author could not determine how mantle cell lymphoma contributed to appendicitis because the lumen of appendix was not occluded by the lymphoma, likely from cytoreduction from chemotherapy. We have a patient with mantle cell lymphoma before the patient received chemotherapy who presented with appendicitis. The appendiceal specimen shows the lumen filled with mantle cell lymphoma.CONCLUSIONThis is a rare case of mantle cell lymphoma causing obstruction of appendiceal lumen and subsequently appendicitis, unaffected by chemotherapy
Gender disparity in Indian library and information science journals: An analytical study
No full textObjective. This study investigates gender disparity in research productivity in Indian Library and Information Science (LIS) journals, focusing on authorship patterns, professional engagement, prolific institutions, and regional productivity.
Methodology. We analyzed 2404 articles with 4583 authors from ten selected Indian LIS journals (2014–2023). Author details, including gender, institutional affiliation, and authorship roles, were collected from biographical notes and recorded in Excel sheets. The analysis involved descriptive statistics and inferential tests (Chi-square tests and correlation analysis) using SPSS software.
Findings. The study revealed a significant gender disparity in Indian LIS research, with male authors representing 71.81% of contributions and dominating first authorship roles (69.3%). Collaborative authorship patterns were also male-dominated, with male-only and male-majority teams prevailing. Faculty members of the University of Delhi and Aligarh Muslim University emerged as the top contributors. Female representation was more visible among research scholars in the KELPRO journal, which showed a balanced gender representation. Regional analyses showed that contributions from New Delhi, West Bengal, and Karnataka were the highest, with minimal representation from states such as Sikkim and Nagaland.
Conclusions. This study highlights the persistence of gender disparity in Indian LIS scholarship and provides valuable insights into authorship dynamics, institutional productivity, and regional representation. These findings offer actionable recommendations for fostering inclusivity and gender equity in Indian LIS research
Fluoroscopic Notching of Left Atrial Disc – A Sign of Prolapse
No full textTransesophageal echocardiography has been used throughout the procedure of transcatheter closure of atrial septal defect due to high resolution images as well as superior operator comfort in assessing device position. However, the centers, lacking the facility of intra-procedural transesophageal echocardiography, carry out the procedure using transthoracic echocardiography which may have higher chances of device malposition. In this case-series, we describe fluoroscopic features of device position or malposition which would prove beneficial to the centers in assessing device position in the transcatheter closure of atrial septal defect performed using transthoracic echocardiography
Longevity of URL citations Cited in LIS journal articles: A Webometric Study
Get PDFThe study investigated the use of URLs as citations and their longevity, based on 966 articles published in selected LIS journals published during 2011-2015. It is found that there are 36,968 references in 966 articles with an average of 38.26 per article. Of the 36,968 references, there are 5,867 URL references. Each of the 5,867 URL citations were checked using W3C link checker to verify their accessibility. The study also found that 46.53% URLs (2,730 out of 5,867) remained active while the remaining 3,137 (53.46%) were found to be missing. The largest number of missing URLs (83.22%) cited in LIS articles are published in the year 2012. The HTTP error 404 - ‘file not found’ error message was the common error 40.36% In this regard the study suggested that the author(s) should check the accessibility of URL citation before it is used in the reference list of the article
Efficiency and equity considerations in pricing and allocating irrigation water
Get PDFEconomic efficiency has to do with how much wealth a given resource base can generate. Equity has to do with how that wealth is to be distributed in society. Economic efficiency gets far more attention, in part because equity considerations involve value judgements that vary from person to person. The authors examine both the efficiency and the equity of different methods of pricing irrigation water. After describing water pricing practices in a number of countries, they evaluate their efficiency and equity. In general they find that water use is most efficient when pricing affects the demand for water. The volumetric, output, input, tiered, and two-part tariff schemes all satisfy this condition and can be efficient although whether efficiency is short-run or long-run, first- or second-best, varies. Pricing schemes that do not directly influence water input -- per-unit areas fees for example -- lead to inefficient allocation. But they are usually easier to implement and administer and require less information. The extent to which water pricing methods can effect income redistribution is limited, the authors conclude. Disparities in farm income are mainly the result of factors such as farm size and location and soil quality, but not water (or other input) prices. Pricing schemes that do not involve quantity quotas cannot be used in policies aimed at affecting income inequality. The results somewhat support the view that water prices should not be used to effect income redistribution because water prices are a poor vehicle for reducing income inequality. But pricing schemes that involve water quota rules can reduce income inequality. The authors demonstrate this with a two-rate tiered pricing scheme combined with equal quotas of the cheaper water.Water Conservation,Environmental Economics&Policies,Water and Industry,Drylands&Desertification,Economic Theory&Research,Town Water Supply and Sanitation,Water Supply and Sanitation Governance and Institutions,Water Conservation,Water and Industry,Environmental Economics&Policies
A Critical Study of the Autobiographical Elements in the Fictional Works of R. K. Narayan
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The M235T polymorphism of the angiotensinogen gene in South Indian patients of hypertrophic cardiomyopathy
No full text Introduction. Hypertrophic cardiomyopathy (HCM) is a complex disorder and genetically transmitted cardiac disease with a diverse clinical course. The objective of the present study was to examine the association of the T704C polymorphism of exon 2 of the angiotensinogen (AGT) gene with HCM in a South Indian population from Andhra Pradesh. Subjects and methods. One-hundred and fifty HCM (90 sporadic hypertrophic cardiomyopathy [SHCM] and 60 familial hypertrophic cardiomyopathy [FHCM]) patients and 165 age- and sex-matched normal healthy controls without known hypertension and left ventricular hypertrophy were included in the study. DNA was isolated from peripheral leukocytes and the region of interest in the AGT gene bearing a missense mutation methionine to threonine substitution at codon 235 (M235T) of exon 2, was amplified by polymerase chain reaction (PCR). The PCR products were subjected to restriction digestion with the enzyme SfaNI. Results. Significant differences were detected in genotypic distribution ( p = 0.04) as well as the allelic frequency ( p = 0.003) between the SHCM patients and controls. The polymorphism did not show any association with FHCM. Conclusion. Our results suggest that the T allele of the AGT gene is significantly associated with SHCM in a South Indian population from Andhra Pradesh. However, we did not find significant association of this polymorphism with FHCM. </jats:p
