Photocatalytic degradation of methylene blue and dye mixture using indium-doped CaWO4 synthesized by sonochemical and microwave-assisted hydrothermal methods.

This study presents indium-doped calcium tungstate for the first time. The photocatalytic and photoluminescent properties of pure and In3+ doped samples were investigated. All pure and indium-doped calcium tungstate particles were synthesized for 30 minutes by two different methods: the sonochemical method (SM) and the microwave-assisted hydrothermal method. The nanoparticles were characterized by X-ray diffraction (XRD), field emission gun-scanning electron microscopy (SEM-FEG), UV-Visible spectroscopy, Brunauer-Emmett-Teller method, and zeta potential analysis. The diffractogram results confirmed the formation of scheelite crystalline structures without forming deleterious phases. The SEM-FEG images show the powder with irregular morphology and agglomerated as rods and kibes. For both methods, samples with 8% In3+ ions showed lower PL intensities with maximum peaks at 479 and 483 nm, suggesting lower e-/h+ pair recombination, which led these samples to present better photocatalytic performance. The photocatalytic activity was estimated from the degradation of the methylene blue (MB) dye under UV light and the sample stability was tested in 3 reuse cycles. The scavenger methodology indicated that h+ is the most active mechanism in the photocatalysis process. The degradation of the dye mixture (MB, MO, and RhB dyes) was also performed.

Correction: Synthesis and evaluation of photocatalytic and photoluminescent properties of Zn2+-doped Bi2WO6.

Correction for 'Synthesis and evaluation of photocatalytic and photoluminescent properties of Zn2+-doped Bi2WO6' by L. X. Lovisa, et al., Dalton Trans., 2022, https://doi.org/10.1039/d2dt03175b.

Synthesis and evaluation of photocatalytic and photoluminescent properties of Zn2+-doped Bi2WO6.

This study consists of the synthesis of zinc-doped Bi2WO6 obtained by the sonochemical method. The XRD results indicated that the samples showed an orthorhombic phase with the P21ab space group without the presence of secondary phases, demonstrating success in the doping process. The results of the photocatalytic tests under the photodegradation of methylene blue showed better performance for the pure sample with 80% degradation during 2 hours of exposure to radiation. The high rate of photogenerated charges accompanied by the low recombination rate of the pairs and e-/h+ were responsible for forming hydroxyl radicals, the predominant oxidative agent of the mechanism. The increase in Zn2+ concentration in the Bi2WO6 matrix promoted inhibition of the photocatalytic properties by the appearance of oxygen vacancies that acted as a charge recombination center. In contrast, photoluminescence was improved by doping with Zn2+. The Bi2WO6:8% Zn2+ sample showed the highest PL intensity. The characteristics of the emitted colors are modulated from the emission spectra and are quantified in terms of the photometric parameters: chromaticity coordinates (x, y), color reproduction index (CRI), luminous radiation efficiency (LER), and purity of color (%) of samples. The adjustment in the colors is promoted as a function of the increase in the Zn2+ concentration observing the transition from: yellow → orange → green. PL is favored by the effect of the dopant (Zn2+) in the matrix, which allows Bi2WO6:Zn2+ to be considered a promising candidate for applications in optical devices. In addition, Bi2WO6 constitutes a high performance photocatalyst for the degradation of methylene blue.

Piroxicam and laser phototherapy in the treatment of TMJ arthralgia: a double-blind randomised controlled trial.

This study aimed to evaluate the efficacy of piroxicam associated with low-level laser therapy compared with single therapies in 32 patients presenting temporomandibular joint arthralgia in a random and double-blind research design. The sample, divided into laser + piroxicam, laser + placebo piroxicam and placebo laser + piroxicam groups, was submitted to the treatment with infrared laser (830 nm, 100 mW, 28 s, 100 J cm(-2) ) at 10 temporomandibular joint and muscle points on each side during four sessions concomitant to take one capsule a day of piroxicam 20 mg during 10 days. The treatment was evaluated throughout four sessions and 30 days follow-up through visual analogue scale (VAS), maximum mouth opening and joint and muscle (temporal and masseter) pain on palpation. The results showed that all the study groups had a significant improvement in the VAS scores (P < 0·05), and there were no significant group differences. Piroxicam was effective in the reduction of joint and muscle pain on palpation (P < 0·05) and showed the lowest temporal pain (P = 0·02) at the 30-day follow-up. The combination of low-level laser therapy and piroxicam was not more effective than single therapies in the treatment of temporomandibular joint arthralgia. The use of piroxicam was more effective in the following 30 days.

[Retrospective study on Latrodectus stings in Bahia, Brazil]. / Estudo retrospectivo de latrodectismo na Bahia, Brasil.

This work is a retrospective study of latrodectism in the State of Bahia, Brazil, from August 1980 to July 1990. The data concerning the accidents were obtained from file cards at the Antivenom Information Center of Bahia (AVICB). Latrodectus curacavienis was the ethiologic agent identified in 28% of the arachnid accidents. The major incidence was registered in urban area (57%) affecting men (70%) more than women, with 10 to 29 year-old age group (58%). Local pain (56%), erythematous papula (29%) and light oedema (17%) were the principal local symptoms. Pain in the limbs (29%), tremor and rigidities (29%), sweating (28%), limbs and arms paresthesia (21%) and abdominal pain (17%) were systemic ones. The treatment was mainly symptomatic (67%) and antivenin serum was used in 21% of the cases. After serotherapy, 64% of the patients left the hospital within less than 24 hours.