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Topic Review
Antioxidants and Carbon-Based Electrodes
Antioxidants are compounds that prevent or delay the oxidation process, acting at a much smaller concentration, in comparison to that of the preserved substrate. Primary antioxidants act as scavenging or chain breaking antioxidants, delaying initiation or interrupting propagation step. Secondary antioxidants quench singlet oxygen, decompose peroxides in non-radical species, chelate prooxidative metal ions, inhibit oxidative enzymes. Based on antioxidants’ reactivity, four lines of defense have been described: Preventative antioxidants, radical scavengers, repair antioxidants, and antioxidants relying on adaptation mechanisms. Carbon-based electrodes are largely employed in electroanalysis given their special features, that encompass large surface area, high electroconductivity, chemical stability, nanostructuring possibilities, facility of manufacturing at low cost, and easiness of surface modification. Largely employed methods encompass voltammetry, amperometry, biamperometry and potentiometry. Determination of key endogenous and exogenous individual antioxidants, as well as of antioxidant activity and its main contributors relied on unmodified or modified carbon electrodes, whose analytical parameters are detailed. Recent advances based on modifications with carbon-nanotubes or the use of hybrid nanocomposite materials are described. Large effective surface area, increased mass transport, electrocatalytical effects, improved sensitivity, and low detection limits in the nanomolar range were reported, with applications validated in complex media such as foodstuffs and biological samples.
  • 924
  • 12 Apr 2021
Topic Review
Sol-Gel and Layer-by-Layer Coatings
The use of urface-engineered coatings for the fire protection of cotton fabrics is continously growing. In this context, two main approaches have been extensively investigated, namely sol-gel derived coatings and layer-by-layer assemblies. These approaches are both capable of providing treated fabrics with outstanding flame-retardant features, when exposed to a flame or an irradiative heat flux.  This review work aims at discussing the recent progresse with respect to both strategies, highlighting current limitations, open challenges, and possible further developments.
  • 924
  • 01 Nov 2020
Topic Review
Structure of Piezoelectric Accelerometers
Compared with other types of sensors, piezoelectric accelerometers have the advantages of a large range, a wide-frequency band, a simple structure, stable performance, good output linearity, etc. The principle of a piezoelectric accelerometer is based on the property of the active element, and its structure is mainly composed of a mass block, a piezoelectric sensitive element, and a base.
  • 924
  • 28 Sep 2023
Topic Review
Synthetic Applications of Aziridinium Ions
Aziridines are three-membered cyclic organic heterocyclic compounds with one nitrogen atom in the ring. 
  • 923
  • 27 Apr 2021
Topic Review
Chemical Rings
The epoxidized group, also known as the oxirane group, can be considered as one of the most crucial rings in chemistry. Due to the high ring strain and the polarization of the C–O bond in this three-membered ring, several reactions can be carried out. One can see such a functional group as a crucial intermediate in fuels, polymers, materials, fine chemistry, etc. 
  • 923
  • 30 Aug 2021
Topic Review
Deep Eutectic Solvents for Biomass-Based Waste Valorization
Biomass waste streams are potential feedstocks for a variety of products such as fuels, polymers, and building blocks. The deep eutectic solvents (DESs), eutectic mixtures of Lewis (or Brønsted) acids and bases with incomplete proton transfer, were intentionally designed by choosing two or more distinct components that could interact via hydrogen bonding. The DESs, often with non-stoichiometric ratios between components, present melting points significantly lower than the starting materials and produce mixtures of charged and neutral species. 
  • 922
  • 14 Oct 2022
Topic Review
Biodegradable Polymers
Biodegradable polymers are those which can degrade into water and carbon dioxide under normal environmental conditions through microbial action, providing compost as a simple and sustainable disposal option.
  • 922
  • 17 Jan 2022
Topic Review
Porphyrins/Chlorins for Viruses Inactivation
The problem of treating viral infections is extremely important both in connection with the emergence of new viral diseases and in connection with the low efficiency of existing approaches to the treatment of known viral infections. This entry is devoted to the use of porphyrins, chlorins, and phthalocyanines for the fight against viral infections using chemical and photochemical inactivation methods. The purpose of this work is to summarize the main approaches developed to date to chemical and photodynamic inactivation of human and animal viruses using porphyrins and their analogs, as well as to analyze and discuss information on viral targets and antiviral activity of porphyrins, chlorins and their derivatives obtained in the last 10-15 years, in order to identify the most promising areas.
  • 921
  • 23 Jun 2021
Topic Review
Silica Aerogel Incorporated Cementitious Composites
Silica aerogels are made of 95% air, the rest being silica crystal (SiO2). They have an open porous structure that is composed of particles with diameter less than 10 nm and pores smaller than 50 nm. Lightweight cement composites with silica aerogel in the form of granulate, thanks to their low thermal conductivity and good mechanical performance, may soon find wide application in the construction sector. An important aspect that guarantees this application is the proper design of the composite, proper selection of its components, improvement of the interfacial zone between the silica aerogel and the cement matrix, and ensuring the durability of the material in the long term.  
  • 920
  • 18 Apr 2022
Topic Review
Mineralogy of Antimony Ores and Antimony Production
Antimony is a metalloid element having common oxidation states of 5+ and 3+. It is a lustrous silvery-white solid, which is quite brittle and exhibits a flaky texture.  Antimony is classified as a critical/strategic metal. Stibnite, jamesonite, and antimony-gold ores are the most common sources of antimony.
  • 920
  • 02 Sep 2022
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