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

Aim: The aim is to evaluate the use of digital megavolt imager (DMI) aS1200 in portal dosimetry with flattening filter free (FFF) beams. Materials and Methods: Dosimetric properties of DMI is characterized at 6MV FFF beams for signal saturation, dose linearity, dependency on dose-rate and source-detector distance (SDD), signal lag (ghosting), and back scatter. Portal dosimetry is done for twenty volumetric modulated arc therapy (VMAT) based stereotactic body radiotherapy (SBRT) plans for the treatment of liver metastases and the results are compared with repeated measurements of Octavius 4D. Results: The detector signal to monitor unit (MU) ratio drops drastically below 25MU. The detector linearity with dose is within 1% and no evidence of signal saturation as such. The aS1200 response variation across various dose rates and SDD is <0.4% and <0.2% respectively. The effect of ghosting increased distinctly at higher dose rate but however it is negligible (0.1%). The impact of back scatter is <0.3% because of additional shielding provided at the back of the detector. The portal dosimetry results of SBRT QA plans evaluated at the gamma criteria of 2mm/2% (DTA/DD) both under global and local mode analysis has shown an average gamma passing rate of area gamma (<1) 97.9±0.8% and 96.4±0.9%. The SBRT QA results observed in aS1200 are inline and consistent with Octavius 4D measured results. Conclusion: The characteristics of aS1200 evaluated at FFF beams have shown its potential ability as QA tool and can be used in SBRT QA for liver metastases with greater confidence. © 2020 Asian Pacific Organization for Cancer Prevention.

World University root node

School of Advanced Sciences

Vellore Campus

Fulltext

Asian Pacific Journal of Cancer Prevention

Dosimetric validation of digital megavolt imager for flattening filter free beams in the pre-treatment quality assurance of stereotactic body radiation therapy for liver metastases

Tissue engineering is one of the potential fields in the domain of regenerative medicine. Engineered scaffolds are an excellent substitute for the conventional use of bone grafts as they are biocompatible, economic, and provide limitless supply with no risk of disease transmission. Gum-based scaffolds present a good scope for studying tissue-engineering models and analyzing controlled drug delivery. Uniform blending of the gums and the presence of the optimal concentration of appropriate crosslinkers are very crucial for biodegradability nature. Gum-based scaffolds containing gellan gum, xanthan gum, polyvinyl alcohol, and hydroxyapatite, cross-linked with either glutaraldehyde (GA) or sodium trimetaphosphate (STMP) were fabricated to study the efficiency of crosslinkers and were characterized for degradation profile, swelling capacity, porosity, mechanical strength, morphology, X-ray diffraction, Fourier-transform infrared, and in vitro biocompatibility. Scaffolds crosslinked with STMP exhibited higher degradation rate at Day 21 than scaffolds crosslinked with GA. However, higher compressive strength was obtained for scaffolds cross-linked with STMP signifying that they have a better ability to resist compressive forces. Superior cell viability was observed in STMP-crosslinked scaffolds. In conclusion, STMP serves as a better crosslinker in comparison to GA and can be used in the fabrication of scaffolds for bone tissue engineering. © 2020 Wiley Periodicals, Inc.

Journal of Biomedical Materials Research - Part B Applied Biomaterials

Crosslinking of gum-based composite scaffolds for enhanced strength and stability: A comparative study between sodium trimetaphosphate and glutaraldehyde

The present study focuses on the synthesis of visible light active curcumin supported TiO2/AC (curcumin-TiO2/AC) through sol-gel and wet impregnation methods for the decolourization of Reactive Blue 160. The characterization technique SEM with EDAX confirms the doping of curcumin and accumulation of TiO2nanoparticles into the pores of activated carbon. Further, the crystalline structure and band gap energy were studied by the X-ray diffraction technique and UV-visible diffuse reflectance spectroscopy, respectively. The inhibition of electron-hole recombination was evidenced by photoluminescence spectroscopy. The photocatalytic activity of the nanocomposites was monitored under visible light irradiation through various optimized conditions, such as pH - 3, catalyst concentration - 0.1 g, irradiation time - 3 h. Improved degradation was observed for curcumin-TiO2/AC due to the narrow band gap and effective charge separation by the surface modifiers compared to TiO2/AC. Additionally, the antimicrobial activity of curcumin-TiO2/AC was tested againstStaphylococcus aureus,Escherichia coliandCandida species. These results indicated that doping of curcumin on TiO2/AC inhibits the recombination of electron-hole pairs to improve the photocatalytic performance in the visible region. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2020.

New Journal of Chemistry

Evaluation of curcumin assistance in the antimicrobial and photocatalytic activity of a carbon based TiO2nanocomposite

Iron (Fe)-doped indium-tin-oxide thin films were prepared using electron beam evaporation technique. The prepared thin films were characterized by XRD, SEM, EDX, UV-Vis-NIR, and VSM techniques to study their structural, compositional, optical, electrical, and magnetic properties. The XRD studies confirmed the cubic structure of the prepared thin films with crystallite size 26 nm. The morphological studies confirmed the formation of nanorods. The EDX spectra confirmed the presence of elements in the desired ratios. A decrease in optical band gap was observed in the Fe-doped ITO thin films. A broad emission peak at 513 nm was observed in the PL spectra. No change was observed in the emission wavelength with increase of Fe concentration. A weak ferromagnetic nature with an anti-ferromagnetic background was observed in all the Fe-doped ITO thin films. A systematic discussion on observed results was provided in the manuscript. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Superconductivity and Novel Magnetism

Influence of Surface Spin Alignment and F-Centers on the Magnetic Behavior of ITO Thin Films

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

We design a photonic crystal fiber (PCF) biosensor, based on the refractive index, capable of operating in terahertz (THz) region. This structure comprises a dual steering wheel (DSW) shape of large noncircular air-hole structure in the cladding region. This PCF is designed using rectangular structured air holes in core, and they are filled with blood components as analytes. We use the full-vectorial finite-element method to optimize the structural parameters and to characterize the proposed PCF. The simulation results demonstrate a high relative sensitivity for water, cytop, plasma, white blood cells, hemoglobin, red blood cells, sylgard184, biotin-streptavidin, polyacrylamide, and bovine serum albumin. As the practical sensor setup requires connecting a single-mode fiber with that of the PCF, we compute the effective area (Aeff), V-parameter (Veff), spot size (Weff), beam divergence (θ), and dispersion (β2) of the proposed PCF over the wide THz range. We envisage that the proposed fiber may not only be useful for the measurement of various blood components but also for polarization-preserving applications in the THz region. © 2020 Society of Photo-Optical Instrumentation Engineers (SPIE).

Optical Engineering

Designing a dual steering wheel microstructured blood components sensor in terahertz wave band

A novel organic nonlinear optical crystal, bis (4-acetylanilinium) tartrate (B4AAT) has been synthesized and successfully grown by a slow evaporation method using acetone as a solvent at ambient temperature. The single-crystal X-ray diffraction study reveals that B4AAT crystallized into a triclinic system with the noncentrosymmetric space group (P1). The crystalline perfection of the grown crystal was affirmed by the High-resolution XRD study. The characteristic functional groups with vibrational assignments and molecular structure of B4AAT were confirmed through Infrared, Raman and NMR spectroscopic analyses. UV–Vis–NIR spectral analysis of the crystal shows 69% of transmittance with a lower cut-off wavelength at 334 nm. The grown crystal was thermally stable up to 143.39 °C. The laser-induced damage threshold of the B4AAT compound was found to be 15.78 GW/cm2 for 1064 nm Nd: YAG laser radiation. The grown B4AAT possesses the low value of dielectric constant and piezoelectric charge coefficient (d33 = 5.86 pC/N) for the supercapacitor and microelectronics industry. The size-dependent of second harmonic generation efficiency of the crystal was found to be 4.6 times higher than that of KDP. The photoluminescence and lifetime measurements of the molecules in the crystal were studied by Fluorescence spectral analysis. The third-order nonlinear optical activity estimated utilizing the Z-scan method reveals that the B4AAT possesses saturable absorption, negative nonlinearity with self-defocusing and optical limiting effect. The aforesaid results confirm that B4AAT crystal is a potential candidate for optoelectronic and nonlinear optical device applications. © 2020 Elsevier B.V.

Optical Materials

Crystal growth, structural, optical and piezoelectric investigations on novel B4AAT (bis-4-acetylanilinium tartrate): A phase matchable second and third-order NLO single crystal for optoelectronic and nonlinear optical device applications

The frequency doubling and tripling can be reached for Nd:YAG laser beam using the single crystal of ammonium dihydrogen phosphate (ADP). The growth and characterization of pure and L-phenylalanine doped ADP crystals are considered in the present contribution. The transparent good quality single crystals are grown using low temperature solution growth technique. The functional group alteration is studied using FT-IR spectroscopy. The larger improvement is observed in linear and nonlinear optical properties of ADP crystals on doping by L-phenylalanine. The reduction in charge carrier density is observed in photoconductivity spectra of all the grown crystals. © 2020 The Author(s)

Arabian Journal of Chemistry

Crystal growth, spectroscopic, second and third order nonlinear optical spectroscopic studies of L-phenylalanine doped ammonium dihydrogen phosphate single crystals

Optik

Novel report on luminescence, linear and laser induced optical traits of potassium aluminium sulphate crystal for photonic device applications

Ammonium dihydrogen phosphate (ADP) is a pioneer kind of nonlinear optical crystal. It can be used in various electro-optical, nonlinear optical applications. The pure and different weight percentage of Picric acid doped ADP single crystals are grown using the slow solvent evaporation technique at room temperature. The powder XRD study shows single phasic nature of all the grown crystals. The photoluminescence study suggests that the dopant causes defect in structure of ADP by virtue of vibration relaxation and self trapping exciton. The dielectric constant and the dielectric loss of all the grown crystals exhibited universal behaviour over frequency range considered. The Correlation Barrier Hopping and the Non Overlapping Small Polaron Tunnelling kind of conductivity mechanism are observed. The grain and grain boundary is indentified using the complex Impedance and the complex modulus spectroscopy. The third order nonlinear optical susceptibility is increased on doping the Picric acid in ADP crystals. The results are discussed here. © 2020 The Physical Society of the Republic of China (Taiwan)