Polyoxometalates (POMs) as metal-oxide anions have exceptional properties like high negative charges, remarkable redox abilities, unique ligand properties and availability of organic grafting. Moreover, the amenability of POMs to modification with different materials makes them suitable as precursors to further obtain new composites. Due to their unique attributes, POMs and their composites have been utilized as adsorbents, electrodes and catalysts in extraction, and electrochemical and optical detection methods, respectively. A survey of the recent progress and developments of POM-based materials in these methods is therefore desirable, and should be of great interest. In this review article, POM-based materials, their properties as well as their identification methods, and analytical applications as adsorbents, electrodes and catalysts, and corresponding mechanisms of action, where relevant, are reviewed. Some current issues of the utilization of these materials and their future prospects in analytical chemistry are discussed.

Dry reforming of hydrocarbons (DRH) is a pro-environmental method for syngas production. It owes its pro-environmental character to the use of carbon dioxide, which is one of the main greenhouse gases. Currently used nickel catalysts on oxide supports suffer from rapid deactivation due to sintering of active metal particles or the deposition of carbon deposits blocking the flow of gases through the reaction tube. In this view, new alternative catalysts are highly sought after. Transition metal carbides (TMCs) can potentially replace traditional nickel catalysts due to their stability and activity in DR processes. The catalytic activity of carbides results from the synthesis-dependent structural properties of carbides. In this respect, this review presents the most important methods of titanium, molybdenum, and tungsten carbide synthesis and the influence of their properties on activity in catalyzing the reaction of methane with carbon dioxide.

Photocatalytic remediation of industrial water pollution has courted intense attention lately due to its touted green approach. In this respect, Keggin-based polyoxometalates (POMs) as green solid acids in photocatalytic reaction possess superior qualities, viz. unique photoinduced charge-transfer properties, strong photooxidative-photoreductive ability, high chemical and thermal stability, and so forth. Unfortunately, it suffers from a large bandgap energy, low specific surface area, low recoverability, and scarce utilization in narrow absorption range. Therefore, the pollutant degradation performance is not satisfactory. Consequently, multifarious research to enhance the photocatalytic performance of Keggin-based POMs were reported, viz. via novel modifications and functionalizations through a variety of materials, inclusive of, inter alia, metal oxides, transition metals, noble metals, and others. In order to advocate this emerging technology, current review work provides a systematic overview on recent advancement, initiated from the strategized synthetic methods, followed by hierarchical enhancement and intensification process, at the same time emphasizes on the fundamental working principles of Keggin-based POM nanocomposites. By reviewing and summarizing the efforts adopted global-wide, this review is ended with providing useful outlooks for future studies. It is also anticipated to shed light on producing Keggin-based POM nanocomposites with breakthrough visible- and solar-light-driven photocatalytic performance against recalcitrant organic waste.

Since its inception, endovascular coil technology has grown substantially as multiple manufacturers entered the market with an ever-increasing number of new products. Practitioners are now inundated with a choice of coils that vary on the basis of factors such as size, composition, stiffness, and detachment mechanism. The seasoned interventionalist had the benefit of evolving with this technology and, therefore, is likely to understand many of the practical nuances of coil development; for more junior practitioners, who did not experience the ongoing changes in technology, this review will provide a basic framework for the fundamentals of coil design.

Tungsten and tungsten compounds are considered toxicologically relatively safe. Concern regarding the potential health and environmental effects of depleted uranium and lead in military applications has lead many countries to explore the possibility of applying toxicologically safer metals. Heavy metal tungsten alloy-based munitions have been therefore introduced as a replacement in munitions and as kinetic energy penetrators. Although the toxicological profiles of all these metals are well known, their internalization as embedded shrapnel may be considered a new route for long-term exposure. Studies in experimental animals and cell culture indicate that pellets based on heavy metal tungsten alloy possess carcinogenic potential previously unseen for depleted uranium and/or lead. Other metals in the tungsten alloy such as nickel or cobalt may contribute to such a risk. Accordingly, the long-term tungsten-related health risk is reason for concern. This article reviews toxicological and clinical literature and provides new perspectives on tungsten and tungsten-based alloys.

The reaction of the WO4(2-) ion in the pH range 2 to 8 was carried out with the following metal ions individually in combination: Mn2+, Mn3+, Fe2+, Fe3+, Co2+, Co3+, Ni2+, Cu1+, Cu2+, Zn2+, Ga3+, Mg2+, In3+, RAsO3(2-), RSbO3(2-). Some 36 heteropolyanions have been isolated in the crystalline form characterized fully. The antiviral activity of these anions has been determined against HIV, herpes respiratory viruses. The redox potentials for these anions have been measured by cyclic voltammetry documented. At pH 8, the anions adopt a Weakley structure at pH 7, the Keggin structure is formed. At pH 6 to 7, the distorted Keggin structure, 1:1:11, is formed. Below pH 6, the distorted Dawson structure is formed. Some anions showed good antiviral activity with positive redox potentials and others with negative redox potentials. When the metal ion is attached to an organic group, a ring-type structure is formed: a 2:5, 2:6, and 1:7 heteropolytungstate.

We found a factor (Factor T) in aged mixtures of tungstate and phosphate which greatly enhances the antibacterial effects of beta-lactams on methicillin-resistant Staphylococcus aureus (MRSA), while Factor T alone did not strongly inhibit bacterial growth. The effect on methicillin-susceptible S.aureus was weak. There was no synergism of Factor T with other classes of antibiotics, nor with other groups of bacteria. Factor T is probably a complex of phosphate and tungstate, and reduced the expression of penicillin-binding protein-2\', thus sensitizing the MRSA strains to beta-lactams.

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