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

Thermal lithography is an alternative technique that can fabricate patterns beyond the diffraction limit. In thermal lithography, it is hard to obtain morphology on demand due to the difficulty in controlling thermal diffusion caused by the long laser pulses. To address this issue, enhanced thermal lithography with multiple femtosecond laser pulse exposure is proposed in this paper. C-Sb2Te3 (CST), a fine-tunable phase change material, is used as a negative heat-mode resist for the first time. The resolution and steepness of the microstructure prepared by this method are obviously enhanced compared with the conventional way. The height of the wet-etched microstructures can be preciously adjusted by tuning the exposure dose of femtosecond laser pulses. Microstructure and thermal field analysis results reveal the origin of the high resolution and fine-tuning. CST-based phase-change memory cell arrays were fabricated with this method to confirm the feasibility and advantage. This work provides an effective way to achieve enhanced thermal lithography in the manufacturing of micro/nanostructure-based electronic and photonic devices. © 2019 Elsevier B.V.

World University root node

School of Advanced Sciences

Vellore Campus

Applied Surface Science

Nanostructure patterning of C-Sb2Te3 by maskless thermal lithography using femtosecond laser pulses

Background: To study and analyze the variatons in delivered doses to rectum and bladder of carcinoma prostate patents by using kilo Voltage (kV) 'Cone Beam Computed Tomography' (CBCT) images. Materials and Methods: 2-Dimensional kilo Voltage (2D kV) Imaging and CBCT were done for seven prostate cancer patents. The deviatons among their shifts were correlated and the volumetric changes of the rectum and bladder were analyzed. Rectum and bladder contours were redrawn on every boost fractons and dose calculaton were performed on CBCT images to study the effect on dose volume histograms. Results: A correlaton coefficient for set-up variatons was within 0.78 for all directons between CBCT soft tssue matching and kV bone match. The mean deviaton of bladder and rectum volume over the boost fractons was -12% to +9% (SD 31cc to 70cc) and -10.2% to+12% (SD 3.1cc to 14.9cc), respectvely. Bladder mean dose variaton was &lt;1.5Gy for all three positons whereas it was &lt;3.65Gy for rectum. D1% dose deviaton from reference plan for bladder was 1.1Gy (CBCT matched positon), 1.4Gy (kV matched positon), and 1.7Gy (no correcton), and for rectum, the deviatons were 1.2Gy, 2.2Gy, 3.6Gy, respectvely. No significant deviaton was found statstcally significant at the low dose region. Conclusion: It is possible to achieve good dose delivery and conformity in target (prostate) with CBCT image guidance rather than kV bone match, but dose contributon to the rectum is dependent on the patent's anatomy, bladder filling, and rectum filling, pertaining to the day of examinaton. © 2020 Novin Medical Radiation Institute. All rights reserved.

International Journal of Radiation Research

Volume and dosimetric analysis of rectum and bladder for prostate carcinoma patients by using kilo voltage cone beam computed tomography (CBCT)

More effective organic charge transfer nonlinear optical material of 2-(4-methlybenzylidene) malononitrile (MBM) has been synthesized via knoevenagel condensation reaction method and single crystals of unprecedented MBM were successfully cultivated in the presence of ethanol solution by the adaption of slow evaporation solution growth method. Cell parameters and phase purity of the obtained MBM crystals were investigated with the help of Single crystal and powder X-ray diffraction analysis. The morphology of the grown crystal was generated using WinXMorph software. Linear optical characterization was carried out in order to figure out its transmittance efficiency (82%), cut-off wavelength (λ = 458 nm) and energy band gap (Eg = 3.05eV) of the title material. Electrical behavior of the MBM crystal was examined on the basis of dielectric properties. Title crystals thermal tolerance and melting point was examined through TG-DSC analysis. The grown MBM crystal was subjected to Single beam Z-scan technique in order to figure out its third order nonlinear optical nature and its susceptibility is compared with other reported centrosymmetric crystals. Considering its large transmittance range, thermal stability and effective NLO performance, MBM is a potential candidate for NLO applications. © 2020 Elsevier B.V.

Optical Materials

Investigation on the growth, optical, electrical, thermal and third order NLO properties of 2-(4-methlybenzylidene) malononitrile (MBM) single crystal

Materials Today: Proceedings

Z-scan studies on organic crystal (E)-1-(2-chlorobenzylidene) cyclododecane-1-one for photonic applications

Rhodamine B (RhB), a toxic dye is environmentally hazardous and harmful to living organisms, which is primarily used in various industries. Multiferroic BiMnO3 (BMO) with (BMO 1) and without (BMO 2) surfactant (CTAB) was synthesized using hydrothermal method, which acts as a photocatalyst for the Rhodamine B dye degradation process. BMO had tested as a photocatalyst for dye degradation of Rhodamine B dye in UV and Visible light irradiation due to its narrow bandgap. On performing various structural and optical characterizations, the structure of as-prepared BMO samples confirmed, and their crystallite size and bandgap were compared for with and without CTAB treated BMO samples. Under UV irradiation, the decomposition of RhB efficiency and decay time had been calculated as 68% and 75 min for BMO 1. In H2O2 assisted visible light irradiation, BMO 2 shows better performance (90% and 55 min). © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Materials Science: Materials in Electronics

Photocatalytic degradation of rhodamine B using BiMnO3 nanoparticles under UV and visible light irradiation

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.

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