Single-Atomic Dispersion of Fe and Co Supported on Reduced Graphene Oxide for High-Performance Lithium-Sulfur Batteries.

High theoretical energy density and low cost make lithium-sulfur (LSB) batteries a promising system for next-generation energy storage. LSB performance largely depends on efficient reversible conversion of elemental sulfur to Li2S. Here, well-designed sulfur host materials including Fe or Co single atoms embedded on N-doped reduced graphene oxide (MNC/G with M = Fe or Co) are proposed to tackle the LSB challenges and enhance the electrochemical performance. Using a combination of Mössbauer spectroscopy and high-resolution scanning electron microscopy, the atomic dispersion of Co and Fe was revealed up to relatively high mass loadings. After optimization of the electrolyte/sulfur (E/S) ratio, FeNC/G shows the most promising cycle performance combining a constant high discharge capacity at low E/S values with the lowest polarization. In particular, the material FeNC/G@S with a high sulfur loading (9.4 mg cm-2) delivers a high area capacity of 7.7 mAh cm-2 under lean electrolyte conditions (6 mL g-1).

Comprehensive assessment of water quality and associated health risks in an arid region in south Iran.

This study aims at investigating the quality of drinking water and evaluating the non-carcinogenic risk of fluoride and nitrate ions in drinking water, and fluoride in tea in Zarrin Dasht, Iran. We focus on tea since it is the most popular drink among Iranian people and in the study region. We collected and analyzed 23 drinking water samples and 23 tea samples from different locations in the study region. Based on the water quality index, the consumed drinking water does not have a good quality in most Zarrin Dasht areas. Accordingly, the water quality index (WQI) is poor and very poor in 70% and 13% of the water samples, respectively. The average fluoride concentration of the tea samples is 2.71 mg/L. The mean values of Fluoride Hazard Index (HIfluoride) are 3.77, 2.77, and 2.33 for children, teenagers, and adults, respectively, which are higher than the safe limit of 1. The Nitrate Hazard Index (HInitrate) is higher than the safe limit of 1 in 8.7% of the samples. The results of the Monte Carlo simulation demonstrate that HIfluoride and HInitrate are higher than 1 in all the groups, except for adults. According to the results of the sensitivity analysis, ingestion rate and body weight have a large effect on HIfluoride and HInitrate, but body weight is inversely associated with sensitivity. According to the Piper diagram, saline water is the predominant type in Zarrin Dasht. Besides, the results of the principal component analysis (PCA) show a high correlation between fluoride and pH, which could be related to the effect of pH on fluoride dissolution and ion exchange. Therefore, appropriate measures are recommended to be taken in order to reduce the amount of fluoride in the drinking water resources of this region. Reduction of tea consumption can also be considered an important factor in decreasing the amount of fluoride intake.

Current Treatments and Therapeutic Options for COVID-19 Patients: A Systematic Review.

INTRODUCTION: COVID-19 is the third rising epidemic in the 21st century that quickly turned into a worldwide pandemic. Many clinical studies have been achieved to investigate treatments to confront COVID-19. Therefore, we conducted a systematic review to describe the recent treatment strategies to treat COVID-19 patients. METHODS: A systematic search was performed in the databases of PubMed, Scopus, Embase, Science direct, Up to date, and Web of Science using the keywords of Coronavirus, COVID-19, SARS-CoV-2, Novel Coronavirus, 2019-nCoV, Treatment, Medicine, Therapy, Intervention, Drug, Medications, and Cure. All the relevant articles were collected from December 2019 to July 2020. RESULTS: We included 58 studies including 38 articles (eleven reviews, ten editorial documents, three case reports, one mix method, one cohort study), and 19 published clinical trials. Review of studies showed that Lopinavir/Ritonavir (n=16), Remdesivir (n=13), Convalescent plasma (n=11), Chloroquine (n=11), Ribavirin (n=9), Hydroxychloroquine sulfate (n=8), Traditional Chinese Medicine (TCM) (n=8), and Arbidol (n=7), were the most frequently therapies used to treat COVID-19 patients. CONCLUSION: In the absence of definitive treatment protocols, recently proposed approaches have appeared to be an effective therapy for accelerating the recovery of COVID-19 patients. Some of these treatments may have been in the early stages of testing. However, future preclinical and clinical trials are warranted to validate findings.

Viral Meningitis Associated With COVID-19 in a 9-year-old Child: A Case Report.

We report first viral meningitis associated with coronavirus disease 2019 (COVID-19) in a patient hospitalized at Imam Hassan Hospital in Bojnurd. The patient was a 9-year-old child with no history of internal disease who referred to the emergency with a complaint of fever, headache and low back pain, about 3 days after the onset of symptoms. finally, viral meningitis was diagnosed with COVID-19.

3D flower-like binary nickel cobalt oxide decorated coiled carbon nanotubes directly grown on nickel nanocones and binder-free hydrothermal carbons for advanced asymmetric supercapacitors.

The development of high performance supercapacitors with high energy densities without sacrificing power densities has always been at the leading edge of the emerging field of renewable energy. Herein, the design and fabrication of innovative high performance binder-free electrodes consisting of coiled carbon nanotubes (CNTs) and biomass-derived hydrothermal carbon spheres (HTCSs) as, respectively, positive and negative electrodes is reported. High performance asymmetric supercapacitors (ASCs) were developed using novel 3D core/shell-like binary Ni-Co oxide (NCO) decorated coiled CNTs directly grown on Ni nano-cone arrays (NCAs) and HTCSs directly deposited on NCAs. Novel 3D structures of NCAs were synthesized via a facile and scalable cathodic electrodeposition route and coiled CNTs were directly grown on them by catalytic chemical vapour deposition (CVD) followed by a facile hydrothermal method to integrally decorate the coiled CNTs/NCAs by 3D flower-like NCO. A one-pot hydrothermal method is also used to direct the synthesis of biomass-derived HTCSs on NCAs to fabricate a novel binder-free negative electrode. The ASC based on NCO@coiled CNTs/NCAs//HTCSs/NCAs not only exhibits superior energy density (72.5 W h kg-1) at a reasonable power density of 1.4 kW kg-1, but also represents remarkable cycling durability (retaining almost over 85% of its initial capacitance after 5000 charge-discharge cycles). The fabricated ASC, therefore, seems to be a potent candidate for practical applications in future high performance energy storage systems.

Kinetic modeling and determination role of sono/photo nanocatalyst-generated radical species on degradation of hydroquinone in aqueous solution.

Experimental findings of sonophotocatalytic process were used in degradation of hydroquinone to assess kinetic modeling and determine the effect of various active radical species. First, the effects of three photocatalytic, sonocatalytic, and sonophotocatalytic processes were studied for hydroquinone removal to determine kinetic constants and calculate the activation energy of reactions, and then the selected process was evaluated to determine active radical species. The reactor was composed of two parts, one included ultrasonic probe (sonocatalytic part) with powers 22, 80, and 176 W and the second part was the location of UV lamp (photocatalytic part) with tubular flow and power 15 W. After three systems were examined and the efficient system was selected, the role of different active species such as hydroxyl radical (OH(·)), superoxide radical (O2 (·-)), hole (h(+)), electrons (e (-)), and single oxygen molecule ((1)O2) and contribution of each of them were determined in hydroquinone degradation. According to tests, the results of this study showed that sonophotocatalytic integrated method as selected system among three systems studied followed the first-order equation for hydroquinone degradation and active hydroxyl species with 45 % and electron and hole with 15 and 10 %, respectively, had the highest and lowest contributions to conversion of hydroquinone. The findings showed that dissolved oxygen increases the capability of active radical formation so that 28.2 % of hydroquinone removal was increased under aeration compared to without aeration. Also, removal efficiency decreased 62 % with N2 injection due to the withdrawal of oxygen from the sample. By adding 25 Mm of sodium azide (NaN3) to stock solution, 46.5 % reduction was developed because single oxygen ((1)O2) played the role of an active species. The advantages of integrated sonocatalytic and photocatalytic method are the generation of active radical species with more variety and ultimately the formation of higher amounts of powerful hydroxyl radical that increases degradation rates of refractory compounds and low-risk internal and final products. It has an appropriate performance in the degradation of refractory compounds by optimizing effective operational factors.

Kinetic study of slaughterhouse wastewater treatment by electrocoagulation using Fe electrodes.

In this study, treatment of slaughterhouse wastewater by electrocoagulation was investigated in batch system using Fe electrodes. The effect of various variables such as electrode number, current density and operating time was tested. Pollutant removal efficiency increased with increasing electrode number and operating time. The biochemical oxygen demand (BOD(5))(,) chemical oxygen demand (COD), total suspended solid (TSS), and total nitrogen (TN) removal efficiencies using eight electrodes at a contact time of 50 min and a current density of 10 A/m(2) were 66, 62, 60, and 56%, respectively. Higher electrode numbers will allow shorter operating times to achieve certain removal efficiencies. Also, removal efficiencies increased by increasing the current density; the highest removal efficiencies of BOD(5,) COD, TSS, and TN at a contact time of 50 min and a current density of 25 A/m(2) were 97, 93, 81, and 84%, respectively. The results also show that the reactor pH varies directly with the current density; at 25 A/m(2), the reactor pH increased from an initial value of 7.1 to 7.7 after 50 min. The experimental results showed that the kinetics of BOD(5), COD, TSS and TN removal could be fitted adequately using a first order kinetic model (higher R(2)).