Evaluation of the performance of N-doped graphene, synthesized by solvothermal method, as anode for Na-ion and Li-ion batteries
Traditional medicine plays a crucial role in healthcare and disease management in African communities; however, the quality and toxicity of these remedies remain largely unknown, particularly concerning the chronic conditions that are managed by traditional medicines.Despite the widespread use of Kigelia africana as a traditional medicine for chronic conditions, its genotoxic and mutagenic effects remain unclear.This study aimed to address this knowledge gap by examining the genotoxic and mutagenic properties of aqueous and ethyl acetate crude extracts of Kigelia africana fruits obtained from the Kazungula District of Zambia.The study used quantitative fluorescence microscopy to determine mutagenicity and genotoxicity and compared the results with the Ames results obtained in this study.The study found that the aqueous extract had no effect on cell viability, while the ethyl acetate extract caused a dose-dependent reduction in cell viability.The effects of the fruit extracts on His+ revertants were comparable to those of the negative control, showing no mutagenic effects.The study also found that the average nuclear area of Vero cells increased significantly with the highest concentration of the ethyl acetate fruit extract, but there was no significant effect on the multi+dual/mononucleated Vero cell ratio following a 48-hour exposure.This study demonstrated for the first time that K. africana fruit extracts are not cytotoxic and do not have mutagenic potential and that the extracts do not exhibit genotoxic effects at therapeutic doses.
While the world is grappling with the SARS-CoV-2 pandemic and striving to minimize the damage caused, another emerging virus called Monkeypox Virus (MPXV) has surfaced, capturing widespread attention and instilling panic among people.There is a fear that this new virus could lead to a scenario similar to, if not worse than, the ongoing COVID-19 crisis.Hence, the objective of this work is to provide an overview of the monkeypox disease to shed light on the characteristics and behavior of this emergent disease, to explore reliable and possible diagnostic methods, and delve into the available preventive and therapeutic measures, including viable drugs and approved vaccines, to mitigate the impact of the illness.Many enigmas still surround this emergent disease, which makes it crucial to emphasize the importance of clarifying its progression and establishing effective control measures; by doing so, we can learn from past experiences and avoid repeating the errors that occurred during the COVID-19 pandemic.
Copper-driven catalyst design for improved oxygen reduction reactions in carbon-based materials
A new emerging virus named Monkeypox virus (MPXV) has recently gained significant attention, captured the headlines and spread panic among people due to the threat it poses to their health and well-being.This review paper aims to provide an overview of the virology of this novel virus, shedding light on its morphology, genetics, and process of replication.Furthermore, it delves into the origin of the virus and describes the diverse routes through which it spreads, as well as our body's immune response against it.Understanding the fundamental characteristics of the MPXV is crucial in order to comprehend its potential impact on public health.Also, exploring its genetics, and studying its replication would aid in the development of effective diagnostic methods and potential treatments, and to identify specific genes and proteins that contribute to its virulence and pathogenicity.While the likelihood of MPXV becoming a pandemic may be low, comprehensive knowledge about the virus and its modes of transmission is crucial to prevent the possibility of large-scale outbreaks.By staying informed and implementing appropriate preventive measures, we can effectively mitigate the impact of this emerging virus and safeguard public health.
Nowadays, the rapid determination of several viruses is highly important. Most of the rapid detection of human pathogen viruses has been developed by using biosensor technology. The detection layer of the biosensor consists of short single-stranded DNA (probe) able to form a duplex with a complementary target nucleic acid fragment with high efficiency and specificity. The probe is associated with a transducer that translates the hybridization event into a physically measurable value based on electrochemical methods. Electrochemical DNA biosensors offer merits such as rapid response, portability, high sensitivity, ease of use, and low detection limit. This review provides an overview of label-based and label-free electrochemical DNA biosensors for the detection of viruses as well as their application in the past four years.
Based on the literature data on the discharge characteristics of Li4Ti5O12 (LTO) and LiNi1/3Co1/3Mn1/3O2 (NMC) electrodes at different temperatures, the discharge curves of batteries composed of LTO and NMC electrodes were calculated. Four models of a battery based on the pristine materials and their modifications (an LTO anode based on a synthesized Cu/Super-P composite and an NMC cathode modified with lithium boron oxide glass (LBO)) are considered. The effect of modification of electrode materials on the temperature dependence of their capacity is estimated. It was found that a battery with a NMC-based cathode modified with LBO coating has good lowtemperature properties and that the cathode modification in its effect on the discharge capacity exceeds the effect of the anode modification. It is shown that a battery with two improved electrodes is superior to other options in the entire temperature range from −30 °C to +20 °C.
Acetonitrile-based electrolytes for lithium
The physiological corrosion resistance of plasma nanocoated 316L stainless steel was studied in protein-containing electrolytes using electrochemical methods. Plasma nanocoatings with thicknesses of 20-30 nm were deposited onto 316L stainless steel coupons in a glow discharge of trimethylsilane (TMS) or its mixture with oxygen gas under various gas ratios. The surface chemistries of the plasma nanocoatings were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Corrosion properties of the plasma nanocoated 316L stainless steel coupons were assessed using potentiodynamic polarization, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) in phosphate-buffered saline (PBS) electrolytes that contain bovine serum albumin (BSA) or lysozyme. It was found that BSA adsorption on the plasma nanocoated 316L coupons was heavily favored. BSA adsorption on the plasma nanocoating surfaces could block charge-transfer reactions between the electrolyte and 316L substrate, and thus stabilize the 316L substrates from further corrosion. In contrast, lysozyme adsorption on the plasma nanocoated specimens was not as pronounced and mildly influenced the corrosion properties of the plasma nanocoated 316L stainless steel.
Heterogeneous photocatalysis is a clean technology where light energy is used to drive redox processes on the surface of semiconductors. Applications include the photoelectrolysis of water, organic synthesis, carbon dioxide fixation, ‘self-cleaning’ surfaces, and the treatment of polluted air and water. Titanium dioxide is the most suitable photocatalyst for water treatment applications because it is chemically and photochemically stable, non toxic, photoactive against a wide range of organic pollutants, inexpensive and readily available. The high photocatalytic activity is largely due to the wide band gap giving a large potential window to drive redox reactions, although this requires UV excitation. Nano-engineering of photocatalytic materials may improve the efficiency of the process. Self-organised, vertically aligned, titania nanotubes were grown by the electrochemical oxidation of titanium metal in the presence of fluorine ions. These materials were compared with compact oxide and nanoparticle (Degussa P25) electrodes for the photocatalytic and electrochemically assisted photocatalytic degradation of phenol and formic acid as model pollutants. It was found that ‘as-prepared’ nanotube films did not give any improvement in efficiency, however, following a post-growth anneal step to improve crystallinity, the nanotube films out-performed both the compact oxide and nano-particulate electrodes for the electrochemically assisted photocatalytic degradation of formic acid and phenol. The improvement in performance is due to the nanostructure providing a high surface area for reaction, aligned channels for mass transfer of reactants and products to and from the surface, efficient hole transfer to solution and good electron transfer to the contact electrode
Recent progress made in our lab. in the field of electrochem. promotion of heterogeneous catalytic gas reactions is reviewed. The phenomenon consists of electrochem. polarization of the catalyst/solid electrolyte interface resulting in a dramatic, non-Faradaic modification of the catalytic reaction rate. Two main aspects have been addressed, the mechanistic interpretation of the phenomenon and the development of bipolar cell configurations suitable for practical applications. Fundamental studies were made using single-pellet type electrochem. cells with yttria-stabilized zirconia (YSZ) solid electrolyte. Promotion of the redn. of NO by propylene over Rh/YSZ catalyst under oxidative conditions at 300C was found to be reversible over an active, essentially metallic, rhodium but irreversible over a deactivated, presumably partially oxidized, catalyst. It was shown that anodic current application with negligible power consumption might efficiently assist the recovery of accidentally lost catalytic activity of rhodium. In situ cyclic voltammetry of IrO2/YSZ catalysts showing a linear relation between voltammetric charge and combustion rate of ethylene suggested that promotion of IrO2 was ruled by the charge stored on it. In situ measurements of work function over RuO2/YSZ catalysts established a clear relation between catalyst work function and surface concn. of chemisorbed oxygen interpreted by formation of surface dipoles between adsorbed species and adsorption sites. Transient behavior of the work function-under and after polarization was closely related to the evolution of the combustion rate of ethylene supporting the idea of promoting oxygen species spreading out over the gas-exposed catalyst surface. On the application side, two new cell designs were developed, a ring-shaped and a multiple-channel configuration both operated in bipolar polarization mode. The current bypass of the ring-shaped cell detd. from current-voltage curves was very low whereas in the multiple-channel configuration both the current bypass and the cell voltage were much higher. Feasibility of electrochem. promotion was successfully demonstrated with both configurations. Promotion of the redn. of NO by propylene in ring-shaped bipolar Rh/YSZ cells and that of the combustion of ethylene in bipolar RuO2/YSZ cells of both configurations were non-Faradaic even at high open-circuit conversions. Realization of efficient bipolar cell configurations for electrochem. promotion is very promising in view of future applications in dispersed-catalytic systems. [on SciFinder (R)]
Electrochem. oxidn. of orgs. at thermally prepd. dimensionally stable metal oxide anodes (DSA) has been studied. In reactions involving only simple electron transfer, oxide electrodes exhibit an electrocatalytic activity similar to that of noble metal electrodes. In oxidn. reactions of more complex mechanism, oxide anodes show no electrocatalytic activity below the potential of oxygen evolution and oxidn. of orgs. can take place only under conditions of simultaneous oxygen evolution. A simplified mechanism of orgs. oxidn. catalyzed by intermediates of oxygen evolution has been proposed distinguishing between two limiting electrode behaviors: (i) At qnon-activeq anodes (typically fully oxidized metal oxides) oxidn. of orgs. occurs at a high potential and leads to their combustion through physisorbed hydroxyl radicals. (ii) At qactiveq electrodes (IrO2, RuO2) the reaction takes place at lower potentials characteristic of the metal oxide and results in a selective oxidn. of the org. compd. at higher oxidized metal oxide surface sites. A kinetic model of orgs. oxidn. competed by oxygen evolution at qactiveq type anodes is also proposed and confirmed by preparative electrolysis. [on SciFinder (R)]
