Enhanced photocatalytic removal of cyanotoxins by Al-doped ZnO nanoparticles with visible-LED irradiation

The ZnO-based visible-LED photocatalytic degradation and mineralization of two typical cyanotoxins, microcystin-LR (MC-LR) and anatoxin-A, were examined. Al-doped ZnO nanoparticle photocatalysts, in Al:Zn ratios between 0 and 5 at.%, were prepared via sol-gel method and exhaustively characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption isotherms. With both cyanotoxins, increasing the Al content enhances the degradation kinetics, hence the use of nanoparticles with 5 at.% Al content (A5ZO). The dosage affected both cyanotoxins similarly, and the photocatalytic degradation kinetics improved with photocatalyst concentrations between 0.5 and 1.0 g L-1. Nevertheless, pH study revealed that the chemical state of a species decisively facilitates the mutual interaction of cyanotoxin and photocatalysts. A5ZO nanoparticles achieved better outcomes than other photocatalysts to date, and after 180 min, the mineralization of anatoxin-A was virtually complete in weak alkaline medium, whereas only 45% of MC-LR was in neutral conditions. Moreover, photocatalyst reusability is clear for anatoxin-A, but it is adversely affected for MC-LR

Visible-light driven sonophotocatalytic removal of tetracycline using Ca-doped ZnO nanoparticles

Highly efficient, long-term, eco-friendly catalysts for water decontamination technology are urgently needed to meet the prioritized objectives of green development and societies worldwide. Ca-doped ZnO were investigated as environmentally friendly sono-photocatalytic system under LED visible light irradiation to efficiently mineralize tetracycline-based antibiotics. The effects of pH, Ca doping, light, ultrasound, and pH on the mineralization of tetracycline by Ca-doped ZnO nanopowders and on the chemical, sono-, photo- and sono-photostability of Ca-doped ZnO nanopowders were systematically investigated. The ZnO-based catalyst with 2 at. % of Ca dopant exhibited the best sono-photocatalytic performance in mineralizing tetracyclines under visible LED light and ultrasound irradiation (i.e., 99% mineralization in 90 min), with excellent reusability and minimal sono-photocorrosion (i.e., 1% of catalyst dissolution in 180 min), which were even greater in the absence of organic pollutants and in the pH range of most natural waters. For Ca-doped ZnO nanopowders, the role of the generated reactive oxygen species under light and ultrasound stimulation and the mechanism of the mineralization of tetracycline were analyzed. In conclusion, the sono-photocatalytic mineralization of antibiotics synergizing visible LED light and weak ultrasound irradiation in the presence of Ca-doped ZnO nanopowders presents an outstanding start to developing highly efficient, long-term, eco-friendly catalysts for efficiently treating emerging organic pollutants

Therapeutic Properties of Vanadium Complexes

Vanadium is a hard, silver-grey transition metal found in at least 60 minerals and fossil fuel deposits. Its oxide and other vanadium salts are toxic to humans, but the toxic effects depend on the vanadium form, dose, exposure duration, and route of intoxication. Vanadium is used by some life forms as an active center in enzymes, such as the vanadium bromoperoxidase of ocean algae and nitrogenases of bacteria. The structure and biochemistry of vanadate resemble those of phosphate, hence vanadate can be regarded as a phosphate competitor in a variety of biochemical enzymes such as kinases and phosphatases. In this review, we describe the biochemical pathways regulated by vanadium compounds and their potential therapeutic benefits for a range of disorders including type 2 diabetes, cancer, cardiovascular disease, and microbial pathology

Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry

In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO3. It is generally accepted that the main reason of the ferroelectric distortion in BiFeO3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic beta-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity - its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO3 in the range from 945 C down to 25 C and found the couplings, which undergo the antiferromagnetic-ferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table

Rituximab efficacy in pediatric patients with refractory nephrotic syndrome

Background: Nephrotic syndrome (NS) in children is a disease of glomerular filtration barrier failure, manifesting with severe proteinuria leading to hypoalbuminemia, hypercholesterolemia, and generalized edema. it could be primary or secondary. In primary NS, also known as idiopathic NS, the histological findings of Primary NS include minimal change disease which mainly respond to steroids (steroid sensitive NS), focal segmental glomerulosclerosis which are usually steroid resistant or membranous nephropathy. Rituximab has been shown to be effective for patients with complicated FRNS/SDNS and refractory SRNS. While the incidence of nephrotic syndrome (NS) is increasing, the morbidity of difficult-to-treat NS is significant.Methods: This is a retrospective cohort study that took place in King Abdulaziz University Hospital from 2012 to 2016. Patients included: Any patient under 18 years, and diagnosed with steroid resistant and dependent nephrotic syndrome. Patients excluded: Any patient above 18 years, and known to have secondary Nephrotic Syndrome.Results: Present study consists of 24 children with nephrotic syndrome (NS) were recruited in the study. In the population 8 patients (33.33 %) were diagnosed with SDNS, while the other 16 patients (66.67%) were diagnosed SRNS. Also, patients who were treated with Rituximab we found that (the mean) number of relapses per year before rituximab was about 2.67±1.49 (standard deviation 1.49), while patient who relapsed after rituximab was about 1.09±1.38 (standard deviation 1.38).Conclusions: Rituximab is a biological agent that started to be widely used in difficult nephrotic syndrome cases. The effectiveness of rituximab is most observed in steroid depended nephrotic syndrome patients since it decreases the frequency of relapses and steroid dependency. However, it has been shown that it is less effective in steroid resistant nephrotic syndrome cases and was associated with significant numbers of relapses

Erratum to: Changes in patterns of uveitis at a tertiary referral center in Northern Italy: analysis of 990 consecutive cases

Erratum to: Changes in patterns of uveitis at a tertiary referral center in Northern Italy: analysis of 990 consecutive case

Study of the La

The La0.2235 Pr0.2235 Nd0.2235 Sr0.33 MnO3 (LPNSM) ceramic has been obtained from oxides by sintering in air. The electrical properties of this material have been studied using ac impedance spectroscopy technique over a wide range of temperatures and frequency. Furthermore, a detailed analysis of the impedance spectrum suggested that the electrical properties of the material are strongly temperature dependent and have a good correlation with the sample microstructure in different temperature ranges