Noncytotoxic Dy3+ -activated glass emits cool white light for near ultraviolet-based white light-emitting diodes, visible lasers, and biomedical applications.

Using the melt quenching technique, a lithium zinc borate glass (LZB) system with trivalent dysprosium ions (Dy3+ ) was synthesized, and the luminescence and lasing properties of these materials were examined for the generation of white light. Structural investigation through X-ray diffraction revealed that the prepared glass had an amorphous nature. The optimized glass containing 0.5 Dy3+ had a direct optical band gap of 2.782 eV and an indirect optical band gap of 3.110 eV. A strong excitation band at 386 nm (6 H15/2 →4 I13/2 ) was recognized in the ultraviolet (UV) light region of its excitation spectrum. Emission bands could be seen in the photoluminescence spectrum at 659, 573, and 480 nm under the 386 nm excitation. These transitions of emission resembled electronic transitions such as (4 F9/2 →6 H11/2 ), (4 F9/2 →6 H13/2 ), and (4 F9/2 →6 H15/2 ). In a pristine glass matrix, the higher intensity ratio of yellow to blue can result in the production of white light. The optimized Dy3+ ion concentration was observed to be 0.5 mol%. In addition, an analysis of lifetime decay was conducted for all synthesized glasses, and their decay trends were systematically investigated. Noticeably, we assessed the photometric parameters and found that they were close to the white light standard. Furthermore, a cytotoxicity study was carried out using lung fibroblast (WI-38) cell lines for the optimized 0.5Dy3+ -doped LZB glass and it appeared to be noncytotoxic. It is clear from the results that the noncytotoxic LZB glass doped with 0.5 Dy3+ ions could be a suggestive choice for the manufacture of white light-emitting diodes and lasers using near-UVs.

Continuance intentions to use FinTech peer-to-peer payments apps in India.

Purpose: The purpose of the present study is to identify the determinants of continuance intentions to use FinTech peer-to-peer (P2P) payment apps in India. Design: A cross-sectional survey of 463 FinTech users was carried out during the pandemic with the help of a digital questionnaire. The study has empirically tested an extended expectancy confirmation model and theory of acceptance to examine the determinants of continuance intentions to use FinTech P2P payment apps. Findings: We demonstrate that confirmation of prior expectations and post-adoption perceived usefulness determine continuance intention to use FinTech payment services. Cognitive acceptance (trust) and normative acceptance (social influence) not only determine behavioural acceptance (willingness to co-create) but also influences continuance intentions. Confirmation of initial expectations during service use determines satisfaction and post-purchase perceived usefulness. Practical implications: The continuous use of FinTech P2P services can be ensured by fulfilling users' post-purchase expected benefits, fostering trust, and social influence. These can be achieved by gearing up internal resources to provide customized experiences that meet customers' expectations and facilitate fruitful interactions. Only if the mobile experience is accessible and meets the expectations of customers, they would appreciate its performance and value in the offerings leading to extensive use of FinTech P2P services. Originality/value: The present paper is based on extended ECM and the theory of acceptance that aim to explain continuance intention to use FinTech P2P payments. The study findings add to the limited body of research in the context of FinTech P2P payments.

Biocompatible Yb3+/Er3+ Co-activated La2(WO4)3 Upconversion Nanophosphors for Optical Thermometry, Biofluorescent, and Anticancer Agents.

Non-cytotoxic upconversion nanocrystals are preferred candidates because they offer exceptional advantages for numerous applications, ranging from optical thermometry to bioimaging/biomedical applications. In this report, we demonstrate the luminescence characteristics and practical utility of a multifunctional upconversion nanophosphor based on Yb3+/Er3+:La2(WO4)3 (LWO) flakes. Strong upconversion green emission was observed from 6-mol % Er3+-doped LWO nanophosphor flakes excited by a 980 nm laser. We further enhanced the upconversion emission considerably by co-doping LWO nanophosphors with Yb3+/Er3+ to exploit energy migration from Yb3+ to Er3+ ions. The exceptional improvement in upconversion green and near-infrared emission was achieved by Yb3+ ion co-doping up to 6 mol %; beyond 6 mol %, emission intensities remarkably dropped due to concentration quenching. Photometric parameters were evaluated with and without Yb3+ ion-doped LWO nanophosphors, which exhibited a high green color purity of 95.6%, to elucidate their energy transfer mechanism. In addition, temperature-dependent upconversion emission trends were evaluated by analyzing the fluorescence intensity ratio, exhibiting higher temperature sensitivity than that previously reported. This suggests the applicability of our proposed nanophosphors to optical thermometry. As for bioimaging applications, the non-cytotoxicity of the optimized nanophosphor was confirmed based on distinct fluorescence images of a normal fibroblast cell line (L929). Furthermore, we demonstrated the strong cytotoxicity of nanophosphors against human colon cancer (HCT-116) cells. Based on the results, non-cytotoxic Yb3+(6 mol %)/Er3+ (6 mol %):LWO upconversion nanophosphor flakes are expected to be exceptional candidates owing to their extensive suitability to the fields of upconversion lasers, optical thermometry, and biomedical and anticancer applications. The results indicate the potential of upconversion materials in the effective execution of multiple strategic applications.

Investigation of Upconversion Photoluminescence of Yb3+/Er3+:NaLaMgWO6 Noncytotoxic Double-Perovskite Nanophosphors.

Bright fluorescent rare-earth-ion-doped upconversion nanomaterials are attractive choices for photonic devices. A remarkable green upconversion emission has been obtained by the sensitizing effect of Yb3+ in a Yb3+/Er3+:NaLaMgWO6 (NLMWO) nanophosphor under near-infrared (NIR) excitation. A citrate sol-gel method was employed to synthesize the nanophosphor samples. The lack of a secondary phase in the X-ray diffraction pattern confirms that the Er3+ and Yb3+ ions are incorporated in the ordered double-perovskite structure. Surface analysis and particle evaluation are performed by field-emission scanning electron microscopy and transmission electron microscopy analysis. Upconversion and downconversion emission performances were systematically studied by varying the dopant concentrations. A strong upconversion green emission can be observed with the naked eye, and it resembles the upconversion spectra of Er3+-doped phosphors. Remarkably, because of an energy-transfer process, the green upconversion emission can be converted into a strong red emission by codoping with Yb3+ ions. We observed the color tuning effect from green to red, which can be controlled by varying the Yb3+ concentration in the codoped phosphors during NIR excitation. A systematic investigation of the upconversion mechanism from Yb3+ to Er3+ doubly doped NLMWO nanocrystals is demonstrated. The upconversion mechanism was evaluated only by varying the excitation power of the laser as well. A strong NIR emission at 1.57 µm corresponding to Er3+ can be significantly enhanced by increasing the codoping concentration of Yb3+ ions. The energy migration pathway is accurately presented. The Commission internationale de l'éclairage color coordinates were analyzed for singly and doubly doped nanophosphors. The cytotoxicity of the codoped nanophosphor system was evaluated using WI-38 cell lines. This optimized codoped nanophosphor material is noncytotoxic; thus, it can be useful for in vitro studies in biological studies. On the basis of the obtained results, the NLMWO:Yb3+/Er3+ nanophosphors can be a promising choice for novel upconversion photonic applications.

Total Salivary Anti-oxidant Levels, Dental Development and Oral Health Status in Childhood Obesity.

BACKGROUND: The objectives of this study were to assess the total antioxidant levels, dental development, and oral health status in childhood obesity. MATERIALS AND METHODS: A total of 120 children aged 6-12 years consisting of both genders from different school along Coastal Karnataka, India were part of the study and were categorized into obese/overweight, and normal children based on body mass index for age and sex. Total antioxidant capacity (TAC) levels determined by phosphomolybidic acid and spectrophotometric method were considered. Oral hygiene index-simplified, modified gingival index and dentition status index were used to analyze oral health status. Dental development was assessed using a clinical method and correlated with standard chronology of human dentition. RESULTS: Levels of the total salivary antioxidants were increased in the study group which is very highly significant when compared with control group, oral health status in both the study group and control group was good. Number of children in study group showing accelerated dental development is relatively less when compared with control group, but is not statistically significant. CONCLUSION: Salivary TAC was significantly high in overweight and obese children than their normal counterparts. Prevalence of dental caries was high in obese/overweight children when compared to normal children.

Brushing-induced surface roughness of two nickel based alloys and a titanium based alloy: a comparative study - in vitro study.

BACKGROUND: Alloys with high nickel content have been increasingly used in dentistry. Alloys have high corrosion rates when exposed to chemical or physical forces that are common intra orally. Titanium is the most biocompatible materials for crowns, fixed partial dentures and implants in the present use, but paradoxically the self-protective oxide film on the titanium can be affected by excessive use of the most common preventive agents in dentistry. Therefore, this study is undertaken in order to draw attention toward the potential effect of prophylactic brushing in a saline medium. MATERIALS AND METHODS: Forty-five wax patterns in equal dimensions of 10 mm × 10 mm × 2 mm were cast in titanium (Grade II) and nickel-chromium. Of the 45 wax patterns, 15 wax patterns were used for preparing cast titanium samples and 30 wax patterns were used for preparing cast nickel-chromium samples and polished. These samples were divided into three groups of 15 samples each. They are brushed for 48 h each clinically simulating 2 years of brushing in a saline tooth paste medium. The surface roughnesses of the samples were evaluated using profilometer, scanning electron microscopes and energy dispersive spectroscopy. RESULTS were subjected to statistical analysis. RESULTS: The statistical analysis of the Rz and Ra surface roughness values were calculated. Significant difference of surface roughness was present in the titanium samples compared to that of the machine-readable cataloguing and Wirolloy (nickel-chromium) samples after the study. To know the difference in the values of all samples before and after, Student's paired t-test was carried out. RESULTS showed that there is a significant change in the Rz and Ra values of titanium samples. CONCLUSION: The present findings suggest that, prophylactic brushing with the fluoridated toothpaste have an effect on the surface roughness of titanium and also to a certain extent, on nickel-chromium. Therefore, careful consideration must be given to the selection of the toothbrushes and toothpastes with the medium abrasives in patients with these restorations. How to cite the article: Acharya BL, Nadiger R, Shetty B, Gururaj G, Kumar KN, Darshan DD. Brushing induced surface roughness of two nickel based alloys and a titanium based alloy: A comparative study - In vitro study. J Int Oral Health 2014;6(3):36-49.