Search

Osteoradionecrosis (ORN) is a nemesis of radiotherapy which adversely affects the life of an individual. It is more often seen with conventional external beam radiotherapy using telecobalt machine. Newer radiotherapy techniques are being used in developed nations to circumvent its inherent disadvantages. A higher incidence of ORN is seen in dentate jaws because of extractions done for odontogenic infections in the post radiation period. Systematic evaluation of oral tissues and instituting appropriate therapeutic and prophylactic measures before, during and after completion of radiotherapy is mandatory. In our hospital since we use telecobalt radiotherapy it was deemed necessary to design our own protocol to reduce the incidence of this debilitating complication. Our protocol is based on recommended guidelines and which has been customized to our patient strata. We present the findings of a retrospective study on patients undergoing radiotherapy in whom this oral management protocol was used. This protocol has been effective in reducing the frequency of osteoradionecrosis at our tertiary care hospital., Competing Interests: Conflict of interestNone., (© The Association of Oral and Maxillofacial Surgeons of India 2021, Corrected publication 2021.)

In this article, the structural and nonlinear optical behaviour of a chalcone derivative, (2E)-1-(4-ethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one have been studied. FT-IR, FT-Raman, and NMR spectroscopy were analyzed to validate the molecular structure. To predict the nonlinear optical characteristics of the chalcone, the DFT approach was used and the experimental results were corroborated by the computations. The bathochromic shift is obtained in linear absorbance spectra and is validated using TD-DFT. Also, the broad emission in the blue region demonstrates the blue light emission property of the sample. Using the finite-field method, the dipole moments, polarizability, first-order and second-order hyperpolarizability parameters have been computed. Ground and excited state dipole moments were quantified by solvatochromism. The third-order nonlinear optical characteristics of chalcone in polar and non-polar solvent media were examined using the open/closed-aperture z-scan technique. The chalcone displayed considerable two-photon absorption with a positive nonlinear absorption coefficient and a positive index of refraction due to the self-focussing effect. Furthermore, the optical limiting study manifests that the investigated chalcone might well be favourable for NLO applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Optoelectronic and the cubic nonlinear optical properties of 4-(4-Bromophenyl)-2-(4-nitrophenyl)-2, 3-dihydro-1H-1, 5-benzodiazepine have been studied. Z-scan technique was used for the third-order nonlinear optical measurements namely, nonlinear absorption, nonlinear refraction, and optical power limiting behaviour employing an Nd: YAG laser of 532 nm wavelength having 5 ns Gaussian pulses. B3LYP/6-311 ++ G (d, p) level of theory was employed for structural optimization, vibrational wavenumber, frontier molecular orbitals, natural bond orbital and population analysis. The MOLVIB programme was used to perform unambiguous vibrational assignments based on potential energy distribution values acquired from normal coordinate analysis. B3LYP and CAM-B3LYP hybrid functions have been employed at the DFT level to calculate the theoretical second-order hyperpolarizability. The substitution of -NO 2 and -Br in this benzodiazepine compound enhances the second-order hyperpolarizability (γ) to the order of 10 -34  esu and, switching of self-defocussing to self-focussing phenomenon. The HOMO-LUMO and optical band gap analysis illustrates that polarizing nature of the molecule vary with substituents. The obtained results indicate that this compound has potential applications in optoelectronics and photonics., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Published by Elsevier Ltd.)

The present study investigates the development of distinct UV-A and UV-B radiation filtering materials through the introduction of a heterocyclic bischalcone derivative [(3,5-bis{[4-(methylsulfanyl)phenyl]methylidene}piperidin-4-one] ( B1 ) into the matrix of PVA/Piscean collagen blend films (1:1) prepared through the solution casting method and characterized. The dopant concentration varied from 0.25 to 4%. The scanning electron microscopy images showed the rough surface due to the uniform dispersion of dopant B1 . The addition of different concentrations of B1 altered the mechanical strength with a proportional increase in Young's modulus (146-317 MPa), tensile strength (23.3-39.21 MPa), and decrease in its elongation at break (158.8-105.2%). As the dopant B1 belongs to the bischalcone class of compounds which absorb in the UV-vis region (370 nm λ max ) due to the α, β unsaturated keto group, it was selected for doping. Dopant concentration-dependent increase in density was observed in films (31-162 mg/cm 3 ). The bathochromic shift in UV absorption from 370 to 390 nm for λ max as well as hyperchromism was evidenced with proportional increase in the concentration of B1 , indicating its capacity to block UV rays. On determining the UV filtering ability for all the prepared films, the one with 4% dopant showed a higher sun protection factor (SPF) with a value of 27.53 and ultraviolet protection factor (UPF) with a value of 58.23. In addition, the degradation of supercoiled PBR322 DNA on UV irradiation was effectively inhibited by these films with a dopant concentration of 0.5-4.0%, which might cause less harm to the skin. The inferences of the experiments would indicate the use of these water-insoluble films as UV blocking potential materials with a merit of SPF and UPF characteristics., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)