Characterization of Co2+- and Fe3+-Codoped TiO2 Nanomaterials for Photocatalytic Degradation of Organic Pollutants under Visible Light Irradiation

In this study, TiO2 nanomaterials were prepared using a solvothermal method and codoped with Co2+ and Fe3+ ions for the photocatalytic degradation of organic pollutants under visible light. The physicochemical properties of the obtained materials were studied by powder X-ray diffraction, field emission electron scanning microscopy, energy-dispersive X-ray spectroscopy, and nitrogen adsorption isotherms. Optical absorption was characterized by UV-vis absorption spectroscopy. The photocatalytic activities of the prepared materials were evaluated through methylene blue (MB) degradation under visible light irradiation. Results showed the excellent performance of MB degradation investigated on TiO2 samples codoped with Co2+ and Fe3+ in comparison with undoped and Co2+-doped TiO2 samples. The codoped TiO2 samples degraded 85%–90% of MB after 120 min, whereas all the prepared TiO2 samples were composed of pure anatase phase and had a spherical-like shape and mean crystalline size ranging from 6.2 nm to 7.8 determined by Scherrer’s equation. The optical absorption of the TiO2 codoped with Co2+ and Fe3+ was significantly enhanced toward the visible light region. The pseudo-second-order kinetic model fits well for the degradation of MB on as-prepared TiO2 codoped with Co2+ and Fe3+

Facile synthesis Cu2O nanomaterials via hydrothermal method: Effect of precursors ratio on structural and morphological characteristics

The single phase Cu2O nanomaterials had been fabricated via facile hydrothermal method using non-toxic precursors of CuSO4.5H2O and Na2SO3 (then, the CuSO4 0.3M and Na2SO3 0.3M solution are mixed with volume ratios of 1:5, 1:6, 1:7 and 1:10, respectively). The observed materials were characterized using fine analysis methods such as X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, and UV-Vis spectroscopy. The fabricated Cu2O samples had flower-like morphology which was assembled from octahedral. The samples had an average crystalline size of ~20.1-23.3 nm and a narrow bandgap of ~1.98 eV. The photocatalytic activity of samples was investigated via Congo red (CR) dye photodecomposition experiment, the catalyst dose and the concentration of CR values were studied as the factors affecting the photocatalytic efficiency. The results showed that the fabricated Cu2O samples had good photocatalytic ability in decomposing the CR solution in the visible region. The Cu2O (M­1-6) sample had the best degradation efficiency of the CR solution was the (reached 91.3% after 300 min under visible light radiation of the 150W Led lamp at the CR concentration of 20 ppm). The photo-decomposition rate constant of M­1-6 sample reached 0.00774 min-1. &nbsp

Efficient Unique Ring Signatures from Lattices

Unique ring signatures (URS) were introduced by Franklin and Zhang (FC 2012) as a unification of linkable and traceable ring signatures. In URS, each member within a ring can only produce, on behalf of the ring, at most one signature for a message. Applications of URS potentially are e–voting systems and e–token systems. In blockchain technology, URS have been implemented for mixing contract. However, existing URS schemes are based on the Discrete Logarithm Problem, which is insecure in the post-quantum setting. In this paper, we design a new lattice-based URS scheme where the signature size is logarithmic in number of ring members. The proposed URS exploits a Merkle tree-based accumulator as building block in the lattice setting. Our scheme is secure under the Short Integer Solution and Learning With Rounding assumptions in the random oracle model

Platelet rich fibrin and MTA in the treatment of teeth with open apices

Abstract Background The present study aimed to evaluate the effectiveness of using platelet-rich fibrin (PRF) as the apical matrix for the placement of MTA in nonsurgical endodontic therapy for teeth with periapical lesions and open apices. Methods Twelve teeth from eleven patients with periapical periodontitis and open apices were enrolled in the study. Nonsurgical endodontic therapy was performed with the PRF used as an apical barrier and the MTA manipulated as an apical plug for further thermoplasticized gutta percha in the remaining part of the root canal. Clinical signs and periapical digital radiographs were recorded and analyzed to evaluate the curing progress after periodical follow-ups of 1, 3, and 6 months. The horizontal dimension of the periapical lesion was determined, and the changes in the dimensions were recorded each time. The Friedman test was used for statistical analysis, with P < .05 serving as the threshold for determining statistical significance. Results All patients had no clinical symptoms after the first month of treatment, with a significant reduction in the periapical lesion after periodical appointments. Conclusions PRF is an effective barrier when combined with MTA for the treatment of teeth with periapical periodontitis and open apices

Side effects following first dose of COVID-19 vaccination in Ho Chi Minh City, Vietnam

Vaccines are strongly recommended globally as an effective measure to prevent serious illness from and spread of COVID-19. Concerns about safety following vaccination continue to be the most common reason that people do not accept the vaccine. This retrospective study was carried out on 4341 people who received the first dose of ChAdOx1 nCoV-19, BBIBP-CorV, or mRNA-1273 vaccine at Jio Health Clinic in Ho Chi Minh City, Vietnam. Post-injection side effects were either reported by participants or actively collected by health care staff by means of telemedicine. Local side effects were reported by 35.5% of all individuals, with pain being the most common symptom (33.3%). Systemic side effects were reported by 44.2% of individuals, with fever (25.3%) and fatigue (21.4%) being the most common. Age ≤60 years, female gender, and ChAdOx1 nCoV-19 were significant independent risk factors for both local and systemic side effects, while a history of allergy was significant as a risk factor for local side effects. A total of 43 individuals (1.0%) reported concerning symptoms of rare severe complications, which were addressed and treated by physicians via Jio Health app