Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Physics

In this study, the hyperthermia efficiency of CoFe2O4 nanoparticles (CFNPs) was enhanced by narrowing their size distribution and increasing their magnetic moment. The CFNPs were synthesized using the solvothermal reflux method. The NPs were crystallized in the face-centered cubic spinel structure (lattice parameter of 8.373 Å) and had a particle size of ~10 nm, as revealed by the X-ray diffraction and transmission electron microscopy (TEM) results, respectively. The high-resolution TEM images of the NPs revealed their single crystal nature. The infrared absorption bands above 700 cm−1 confirmed the formation of octahedral and tetrahedral ligands on the surface of the NPs. The thermal analysis profiles of the synthesized NPs showed that the surface ligands decomposed at approximately 360 °C. The nanocolloids prepared using the NPs showed stable dispersion with a zeta potential of −17.7 mV. The X-ray photoelectron spectroscopy results revealed the presence of Co2+, Fe3+, and O2− in the NPs. The NPs existed in the superparamagnetic state with a maximum mass magnetization of 71 emu g−1, which is close to the theoretical value. The magnetic hyperthermia property of the NPs was investigated by determining their specific heat generation rate (SHGR) under biocompatible alternate magnetic field parameters. The NPs were capable of heating 185.32 W g−1. This value is greater than the SHGR reported previously for CFNPs synthesized by other methods. © 2020 Elsevier Ltd and Techna Group S.r.l.

World University root node

School of Advanced Sciences

Vellore Campus

Ceramics International

Synthesis, characterization and magnetic hyperthermia properties of nearly monodisperse CoFe2O4 nanoparticles

Chiral interactions in magnetic systems can give rise to rich physics manifested, for example, as nontrivial spin textures. The foremost interaction responsible for chiral magnetism is the Dzyaloshinskii-Moriya interaction (DMI), resulting from inversion symmetry breaking in the presence of strong spin-orbit coupling. However, the atomistic origin of DMIs and their relationship to emergent electrodynamic phenomena, such as topological Hall effect (THE), remain unclear. Here, we investigate the role of interfacial DMIs in 3d-5d transition metal-oxide-based LaMnO3/SrIrO3 superlattices on THE from a chiral spin texture. By additively engineering the interfacial inversion symmetry with atomic-scale precision, we directly link the competition between interfacial collinear ferromagnetic interactions and DMIs to an enhanced THE. The ability to control the DMI and resulting THE points to a pathway for harnessing interfacial structures to maximize the density of chiral spin textures useful for developing high-density information storage and quantum magnets for quantum information science. © 2020 American Association for the Advancement of Science. All rights reserved.

Fulltext

Science Advances

Interfacial tuning of chiral magnetic interactions for large topological Hall effects in LaMnO3/SrIrO3 heterostructures

Alignment between the radiation isocenter and imaging isocenter is critical to ensure accurate proton dose deposition in the patient. The purpose of the current study is to perform a comprehensive evaluation of the coincidence (planar kV X-rays vs. pencil proton beam) among three, beam-matched pencil beam scanning (PBS) gantries of a ProteusPLUS proton therapy system. For proton radiation isocenter measurement, a cone-shaped scintillator detector, XRV-124, was utilized. To test the impact of gantry angle on the beam coincidence, measurements at 12 different gantry angles were performed in the study. Additionally, the energy dependency on beam coincidence was investigated by acquiring measurements for a total of 63 different energies ranging from 70─225&nbsp;MeV at increments of 2.5&nbsp;MeV. The measurements were performed in all three beam-matched gantries (GTR1, GTR2, and GTR3). A correction of ≤ 0.3&nbsp;mm was applied in the imaging system to account for the imaging isocenter shift as the gantry rotates from 0° to 330°. The beam coincidences in X, Y, and Z were within ± 1.0&nbsp;mm for 63 different energies at 12 different gantry angles in all three beam-matched gantries. The beam coincidence results among three gantries (GTR1, GTR2, and GTR3) ranged from − 0.9 to 0.7&nbsp;mm in the lateral (X), − 0.8 to 0.5&nbsp;mm in the longitudinal (Y), and − 0.7 to 0.7&nbsp;mm in the vertical (Z) directions. Overall, the mean isofocus of radiation isocenter was 0.4 ± 0.2&nbsp;mm in GTR1, 0.5 ± 0.2&nbsp;mm in GTR2, and 0.4 ± 0.2&nbsp;mm in GTR3. Given the consistent agreement (&lt; 1.0&nbsp;mm) between radiation and imaging isocenters for all three rooms, it appears feasible to confidently generate proton treatment plans for one treatment room and deliver in the other beam-matched rooms. © 2020, Australasian College of Physical Scientists and Engineers in Medicine.

Australasian Physical and Engineering Sciences in Medicine

Quantification of radiation and imaging isocenter coincidence of a multi-room PBS proton therapy system

Background: Dysfunction of blood vessel leads to aneurysms, myocardial infarction and other thrombosis conditions. Current treatment strategies are transplantation of blood vessels from one part of the body to other dysfunction area, or allogenic, synthetic. Due to shortage of the donor, painful dissection, and lack of efficacy in synthetic, there is a need for alternative to native blood vessels for transplantation. Methods: Human umbilical-cord tissue obtained from the hospital with the informed consent. Umbilical-cord blood vessels were isolated for decellularization and to establish endothelial cell culture. Cultured cells were characterized by immunophenotype, gene expression and in vitro angiogenesis assay. Decellularized blood vessels were recellularized with the endothelial progenitors and Wharton jelly, CL MSCs (1:1), which was characterized by MTT, biomechanical testing, DNA content, SEM and histologically. Bioengineered vessels were transplanted into the animal models to evaluate their effect. Results: Cultured cells express CD31 and CD14 determining endothelial progenitor cells (EPCs). EPCs expresses various factors such as angiopoitin1, VWF, RANTES, VEGF, BDNF, FGF1, FGF2, HGF, IGF, GDNF, NGF, PLGF, NT3, but fail to express NT4, EGF, and CNTF. Pro and anti-inflammatory cytokine expressions were noticed. Functionally, these EPCs elicit in vitro tube formation. Negligible DNA content and intact ECM confirms the efficient decellularization of tissue. The increased MTT activity in recellularized tissue determines proliferating cells and biocompatibility of the scaffolds. Moreover, significant (P < 0.05) increase in maximum force and tensile of recellularized biomaterial as compared to the decellularized scaffolds. Integration of graft with host tissue, suggesting biocompatible therapeutic biomaterial with cells. Conclusion: EPCs with stem cells in engineered blood vessels could be therapeutically applicable in vascular surgery. [Figure not available: see fulltext.] © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Materials Science: Materials in Medicine

Endothelial progenitor/stem cells in engineered vessels for vascular transplantation

The emerging development of sensing technology initiates innovative sensors achieving low-cost to facilitate practical realization. An interesting crush of the work is to propose a simple structural sensor and to analyze the different schemes of the metal coating by stimulated emission of Raman scattering (SERS) intensification. For the first time, we propose a simple geometrical photonic crystal fiber refractive index based sensor (PCF-RIBS) with three different Schemes A, B, and C, i.e., gold (A) layer-coated surface plasmon resonance (SPR) based D-type PCF-RIBS; Au with titanium-di-oxide (TiO2) layer-coated SPR D-type PCF-RIBS; and Au + TiO2 grating-coated localized surface plasmon resonance (LSPR) D-type PCF-RIBS. Characterizing the three different Schemes A, B, and C using finite element method simulation shows, a maximum wavelength sensitivity of 48,000 nm/RIU, 52,000 nm/RIU and 75,000 nm/RIU, respectively, for a wide range of analyte-refractive index from 1.33 to 1.45 and operates in the wavelength range from 500–2000 nm. Of all the Schemes, Scheme C is found to excite a relatively larger number of surface-plasmons. Eventually, it exhibits improved sensing performances compared to SPR based Schemes A and B. Consequently, it would turn out to be an appropriate candidate to detect a broad range of biological and chemical sample detection. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Sensors (Switzerland)

Highly sensitive localized surface plasmon polariton based d-type twin-hole photonic crystal fiber microbiosensor: Enhanced scheme for sers reinforcement

Herein we report the synthesis of tin oxide (SnO2) and sodium hexahydroxostannate (Na2 [Sn(OH)6]) by varying the reaction parameters and established their ORR activity performance in the single chamber microbial fuel cell (sMFC) as cathode catalyst in both pure and mixed culture environments. The electrochemical studies reveal that the Na2 [Sn(OH)6] catalyst synthesized with higher concentration of NaOH has greater ORR catalytic activity than others in terms of onset potential and current density with a four-electron transfer process. The higher power density is also obtained using the same catalyst in the pure and mixed inoculum, which is comparable to the benchmark Pt/C in a sMFC. The developed cathode electrocatalyst can play a cost-effective material for the enriched energy recovery in the sMFC and/or other such electrochemical devices. © 2020 Elsevier B.V.

Journal of Power Sources

Improved bioelectricity generation of air-cathode microbial fuel cell using sodium hexahydroxostannate as cathode catalyst

We propose a novel method for the selection of optimal beam angles in Intensity Modulated Radiation Therapy (IMRT). The proposed approach uses an objective function based metric called “target-to-critical organ objective function ratio” to find out the optimal gantry angles. The beams are ranked based on this metric and are accordingly chosen for IMRT optimization. We have used the Pinnacle TPS (Philips Medical System V 16.2) for performing the IMRT optimization. In order to validate our approach, we have applied it in four clinical cases: Head and Neck, Lung, Abdomen and Prostate. Basically, for all clinical cases, two set of plans were created with same clinical objectives, namely Equal angle plan (EA Plan) and Suitable angle Plan (SA Plan). In the EA plans, the beam angles were placed in an equiangular manner starting from the gantry angle of 0°. In the corresponding SA plans, the beam angles were decided using the guidance provided by the algorithm. The reduction in OAR mean dose and max dose obtained in SA plans is about 3 to 16% and 3 to 15% respectively depending upon the treatment site while obtaining equal target coverage as compared to their EA counterparts. It takes approximately 15–25 min to find the optimal beam angles. The results obtained from the clinical cases indicate that the plan quality is considerably improved when the beam angles are optimized using the proposed method. © 2019 Associazione Italiana di Fisica Medica

VIT Unitversity

Physica Medica

Objective function based ranking method for selection of optimal beam angles in IMRT

Chalcogenide based phase change random access memory (PCRAM) holds great promise for high speed and large data storage applications. This memory is scalable, requires a low switching energy, has a high endurance, has fast switching speed, and is nonvolatile. However, decreasing the switching time whilst increasing the cycle endurance is a key challenge for this technology to replace dynamic random access memory. Here we demonstrate high speed and high endurance ultrafast transient switching in the SET state of a prototypical phase change memory cell. Volatile switching is modeled by electron-phonon and lattice scattering on short timescales and charge carrier excitation on long timescales. This volatile switching in phase change materials enables the design of hybrid memory modulators and ultrafast logic circuits. © 2020

Journal of Materials Science \& Technology

Resistance modulation in Ge2Sb2Te5

The paper presents a study of the surface and subsurface characteristics induced by laser peening without coating (LPwC) and dual shot peening (DSP) on the duplex aged Ti-15 V-3Al-3Cr-3Sn alloy. In 3D-optical topography analysis, DSP resulted in a six-fold enhancement in the surface roughness (Sa). Whereas, LPwC resulted in unaltered surface roughness (Sa) compared to the polished/unpeened sample. In cross-sectional microstructure studies, deformed grains and heat affected zones were observed in the near surface region of shot peened, and laser peened samples respectively. Moreover, compared to bulk hardness, shot peening and laser peening has resulted in maximum increment of ~28% and ~12% in microhardness of the near peened surface region respectively. © 2020, Springer Nature Singapore Pte Ltd.

Department of Manufacturing Engineering

School of Mechanical Engineering

Lecture Notes in Mechanical Engineering Advanced Surface Enhancement

A Comparison of Surface and Sub-surface Features Induced by Shot Peening vs. Laser Peening on a Duplex Aged Beta Ti Alloy

Introduction: The aim of this study was to determine the accuracy of two different immobilization methods in patient positioning in cranial radiotherapy. The six-dimensional (6D) target localization accuracy of using a dedicated stereotactic mask was compared with that of a conventional head mask by the ExacTrac system. Material and Methods: A total of 56 patients with cranial lesions were included in this study (26 patients with a dedicated stereotactic mask and 30 subjects with a conventional head mask). The ExacTrac image-guided positioning system was utilized to obtain daily translational and rotational patient positioning displacement from the intended position. The 6D setup data was analyzed to obtain population mean, systematic and random errors, and three-dimensional (3D) vector shifts in all the patients. Results: The population mean values of setup errors were comparable with both immobilization systems; however, the spread as indicated by population systematic and population random errors was more in the use of a conventional head mask. The mean values of the 3D vector shifts were 2.09±1.00 and 4.51±3.38 mm with the use of a dedicated stereotactic mask and conventional head mask, respectively. The frequency distribution of maximum rotational deviation and statistical analysis demonstrated a significant difference in immobilization accuracy between stereotactic immobilization and 3-clamp immobilization (P&lt;0.05). Conclusion: The results revealed that there was a significant reduction in target positioning errors with a dedicated stereotactic mask, compared to that with a conventional cranial mask. Furthermore, a dedicated stereotactic mask is required to keep rotational deviations within system correctable limits. © xxxx **