Showing papers by "Somnath C. Roy published in 2017"
TL;DR: The results suggest that the mechanisms of cell death do not seem to be mediated by apoptosis, through caspases 3/7 activation, but by involving membrane potential and imbalance in physiological elements such as P, K and Ca.
53 citations
TL;DR: It is concluded that VIV O-acac species may be transported in blood by transferrin, and at very low complex concentrations speciation calculations suggest that [(VO)(apoHTF)] species form.
Abstract: [VO(acac)2 ] is a remarkable vanadium compound and has potential as a therapeutic drug. It is important to clarify how it is transported in blood, but the reports addressing its binding to serum proteins have been contradictory. We use several spectroscopic and mass spectrometric techniques (ESI and MALDI-TOF), small-angle X-ray scattering and size exclusion chromatography (SEC) to characterize solutions containing [VO(acac)2 ] and either human serum apotransferrin (apoHTF) or albumin (HSA). DFT and modeling protein calculations are carried out to disclose the type of binding to apoHTF. The measured circular dichroism spectra, SEC and MALDI-TOF data clearly prove that at least two VO-acac moieties may bind to apoHTF, most probably forming [VIV O(acac)(apoHTF)] complexes with residues of the HTF binding sites. No indication of binding of [VO(acac)2 ] to HSA is obtained. We conclude that VIV O-acac species may be transported in blood by transferrin. At very low complex concentrations speciation calculations suggest that [(VO)(apoHTF)] species form.
37 citations
TL;DR: Overall, the data confirm that these Casiopeínas may bind to HSA and may be transported in blood serum by this protein; this might allow some selective tumor targeting, particularly in the case of Cas-II-Gly.
27 citations
TL;DR: The ultra-fine nano branches grown on the MLNTs are effective in increasing light absorption through multiple scattering and improving charge transport/transfer efficiencies by enlarging semiconductor/electrolyte interface area.
Abstract: Hierarchically structured nanomaterials play an important role in both light absorption and separation of photo-generated charges. In the present study, hierarchically branched TiO2 nanostructures (HB-MLNTs) are obtained through hydrothermal transformation of electrochemically anodized TiO2 multi-leg nanotubes (MLNT) arrays. Photo-anodes based on HB-MLNTs demonstrated 5 fold increase in applied bias to photo-conversion efficiency (%ABPE) over that of TiO2 MLNTs without branches. Further, such nanostructures are wrapped with reduced graphene oxide (rGO) films to enhance the charge separation, which resulted in ~6.5 times enhancement in %ABPE over that of bare MLNTs. We estimated charge transport (η tr) and charge transfer (η ct) efficiencies by analyzing the photo-current data. The ultra-fine nano branches grown on the MLNTs are effective in increasing light absorption through multiple scattering and improving charge transport/transfer efficiencies by enlarging semiconductor/electrolyte interface area. The charge transfer resistance, interfacial capacitance and electron decay time have been estimated through electrochemical impedance measurements which correlate with the results obtained from photocurrent measurements.
10 citations
01 Jun 2017
TL;DR: In this article, an implementation of the immersed boundary method in continuous casting simulation involving boundary movement has been demonstrated and a parallel programming paradigm using message passing interface has been implemented to obtain enhanced computational efficiency.
Abstract: This article demonstrates implementation of immersed boundary method in continuous casting simulation involving boundary movement. In this methodology, the immersed boundary method is coupled with the second-order accurate finite difference solution of unsteady three-dimensional heat conduction equation. The moving molten metal front is modelled using the immersed boundary method in a Cartesian mesh framework that provides simplicity in its implementation and reduces the computational time as compared to the adaptive mesh solutions. A parallel programming paradigm using message passing interface has been implemented to obtain enhanced computational efficiency. This study has focused on capturing moving boundary during continuous casting and predicts the temperature distribution and shell thickness under different cooling ambiences and casting function. Good agreements with published data and correlations are obtained through numerical analysis. Mould-region shell thickness agrees well with Chipman–Fonders...
7 citations
01 Jan 2017
TL;DR: A simple and robust methodology has been proposed with good mass conservation property that results in smooth pressure fluctuations over moving surfaces that shows a second order accurate mass conservation.
Abstract: Spurious pressure fluctuation and poor mass conservation are considered as the limitations of immersed boundary method (IBM). Over last decade, various implementations are developed to overcome these issues, which are usually mathematically involved and computationally expensive. In this paper, a simple and robust methodology has been proposed with good mass conservation property that results in smooth pressure fluctuations over moving surfaces. A simple quadratic interpolation/extrapolation scheme is used for reconstruction of solution at immersed and ghost nodes in. The proposed scheme has been implemented for fixed and moving three-dimensional boundaries and validated with available literature data. Overall second-order accuracy has been maintained. The achieved results show a second order accurate mass conservation. Spurious pressure fluctuations are also observed to disappear with mesh refinement.
1 citations
TL;DR: In this article, the authors demonstrate implementation of a mass-conserving sharp-interface immersed boundary for simulation of flows in branched arterial geometries, which can be used as a detection tool for arterial diseases.
Abstract: The present work demonstrates implementation of a mass-conserving sharp-interface immersed boundary for simulation of flows in branched arterial geometries. A simplistic two-dimensional arterial junction is considered to capture the preliminary flow physics in the aortic regions. Numerical solutions are benchmarked against established available experimental PIV results in Ensley et al (Annu. Thorac. Surg. 68(4):1384–1390, 1999) and numerical predictions in Gilmanov and Sotiropoulos (J. Comput. Phys. 207(2):457–492, 2005) and de Zelicourt et al (Comput. Fluids 38(9):1749–1762, 2009). Simulations are further carried out for pulsated flows and effects of blockages near the junctions (due to stenosis or atherosclerosis). Instabilities in the flow structures near the junction and the resulting changes in the downstream pulsation frequency were observed. These changes account for the physiological heart defects that arise from the poorly working valve (due to blockage), giving rise to chest pain and breathing instability, and can potentially be used as a detection tool for arterial diseases.
1 citations
23 May 2017
TL;DR: In this article, mesoporous titania is prepared by sol-gel method and enzymatic biosensing of glucose is done with mesophorous tiatania on ITO coated glass plates using photoelectrochemical method and mechanism of sensing is discussed.
Abstract: Mesoporous titania is prepared by sol-gel method The enzymatic biosensing of glucose is done with mesoporous tiatania on ITO coated glass plates using photoelectrochemical method and mechanism of sensing is discussed