Effect of titanium dioxide nanocoating on the colour stability of room temperature vulcanizing maxillofacial silicone-an invitro study.

OBJECTIVE: The aim of this in vitro study was to evaluate the effect of an oxide nanocoating to prevent colour degradation of maxillofacial silicone elastomers following accelerated ageing. MATERIAL AND METHODS: Specimens (N = 40) of specified dimensions were fabricated in Factor II room temperature vulcanizing (RTV) silicone and processed according to the manufacturer's instructions. Two groups were classified with 20 specimens each. Specimens in the first group were coated with titanium dioxide (TiO2) by atomic layer deposition technology. The colour stability test was conducted with a UV-VIS spectrometer (Schimadzu) for both titanium dioxide nanocoated and uncoated specimen groups after subjecting them to accelerated ageing. It was analysed using the CIE L*a*b method. RESULTS: The average colour change was highest for uncoated specimens (2.868), and the average colour change for titanium dioxide-coated specimens was significantly low (1.774). The average colour change of uncoated specimens (2.868) was close to the acceptable threshold value (3), and that of coated specimens (1.774) was far below the acceptable threshold (3). CONCLUSIONS: The colour change that occurred in titanium dioxide nanocoated specimens following accelerated ageing was significantly lower than that in the uncoated group, showing that the TiO2 nanocoating was effective in reducing the colour degradation of silicone elastomers. CLINICAL RELEVANCE: Maxillofacial prostheses fabricated from silicone elastomers go through undesirable colour degradation over time. The development of a scientific technique that retards the colour deterioration of silicone prostheses would be of great clinical significance.

Flexible and self-standing nickel ferrite-PVDF-TrFE cast films: promising candidates for high-end magnetoelectric applications.

Polymer-based magnetoelectrics are identified as a newly emerging area of research due to their profound potential applications centered on spintronic technology. In line with this, we have developed a novel, flexible nickel ferrite (NiFe2O4)-PVDF-TrFE (NF-PVDF-TrFE) polymer based magnetoelectric film, with excellent magnetoelectric coupling at room temperature. Nanocomposite films were prepared by the solution cast method, in which the nickel ferrite nanoparticles with different weight percentages (2, 4, 8 and 16%) were incorporated in the electroactive PVDF-TrFE polymer matrix. The ferroelectric ß-crystalline phase of PVDF-TrFE was confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Raman studies. Dielectric and thermal properties of the composite films were found to be substantially improved with the addition of magnetic nanoparticles. Ferroelectric and magnetic characteristics of the composite films were also considerably improved with an increase in NiFe2O4 concentration. A magnetic saturation (Ms) of 4.81 emu g-1 and a ferroelectric maximum polarization of 18.9 µC cm-2 were shown by the composite film at room temperature for 16 wt% loading of NF nanoparticles. Besides these functionalities, ac and dc magnetoelectric coupling coefficients of 69 mV cm-1 Oe-1 and 90 mV cm-1 Oe-1 were obtained for 16NF-PVDF-TrFE along with excellent mechanical stability. These flexible and self-standing magnetoelectric composite films with enhanced magnetoelectric coupling coefficients at room temperature could be suitable candidates for the development of ultramodern information storage devices, memory devices, signal processing devices etc.

Dopamine functionalization of BaTiO3: an effective strategy for the enhancement of electrical, magnetoelectric and thermal properties of BaTiO3-PVDF-TrFE nanocomposites.

Electro-active polymer-ceramic composite systems are emerging materials in the fields of nanoelectronic, microelectromechanical and macroelectronic device applications. Still more precise and concise research studies have yet to come in the areas of energy storage, harvesting, energy conversion, etc. In line with this, we have synthesized and analyzed PVDF-TrFE based nanocomposites of both functionalized and non-functionalized BaTiO3 (BTO). All the samples were prepared as free standing films by employing a solvent cast method. A systematic study of structural, morphological, thermal, dielectric, ferroelectric, piezoelectric and magnetoelectric (ME) properties has been carried out. It has been reported that the addition of BTO nanoparticles (with and without functionalization) into a polymer matrix substantially improved the properties of the nanocomposite. By performing the above mentioned characterization, it could be proved that dopamine functionalized BTO (DBTO) samples are better choices for the above mentioned applications including magnetoelectric applications, than the non-functionalized ones.

Evaluation of Interleukin-17 and Interleukin-23 in Pterygium: Immunohistochemistry Study.

PURPOSE: To compare the interleukin-17 (IL-17) and interleukin-23 (IL-23) positive cell counts between pterygium and normal conjunctiva. DESIGN: A case-control study. METHODS: This study received ethical approval (NMRR Research ID 23957) and informed consent was obtained from all participants. It involved 20 participants with 20 samples of pterygium and 20 samples of normal conjunctiva that were obtained from the same eye of each participant. All the participants underwent history taking, slit lamp examination, and pterygium excision surgery. Both samples underwent immunohistochemistry procedure. Pretreatment procedure was conducted using heat-induced epitope retrieval with PT link, subsequently followed by EnVision FLEX staining procedure and incubation with anti‒IL-17 antibody and anti‒IL-23 antibody. Slides were examined in high-power fields (400x) for both samples in 3 different fields. Total positive stained cell counts in all 3 fields with IL-17 and IL-23 between pterygium and normal conjunctiva were analyzed by using Wilcoxon signed rank test. RESULTS: IL-17 positive cell counts for normal conjunctiva showed mean 196.10 ± 80.487 but for pterygium was 331.10 ± 108.416. As for IL-23, the mean for positive cell counts for normal conjunctiva was 62.10 ± 33.462 and IL-23 positive cell counts for pterygium showed mean 102.95 ± 41.378. Both IL-17 and IL-23 were significantly increased in pterygium compared with normal conjunctiva (P < 0.001). CONCLUSIONS: Both IL-17 and IL-23 were found to be significantly higher in the pterygium group than in the normal conjunctiva group with P < 0.001 by Wilcoxon signed rank test.