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Topic Review
Nonmetallic Electrocatalysts for Oxygen Reduction Reactions
As a key role in hindering the large-scale application of fuel cells, oxygen reduction reaction has always been a hot issue and nodus. Nonmetallic catalysts have a low cost, good stability and resistance in oxygen reduction reactions. 
  • 298
  • 21 Jul 2023
Topic Review
Nonaqueous Titration
Nonaqueous titration is the titration of substances dissolved in solvents other than water. It is the most common titrimetric procedure used in pharmacopoeial assays and serves a double purpose: it is suitable for the titration of very weak acids and very weak bases, and it provides a solvent in which organic compounds are soluble. The most commonly used procedure is the titration of organic bases with perchloric acid in anhydrous acetic acid. These assays sometimes take some perfecting in terms of being able to judge the endpoint precisely. The Karl Fischer titration for water content is another nonaqueous titration, usually done in methanol or sometimes in ethanol. Since water is the analyte in this method, it cannot also be used as the solvent.
  • 745
  • 14 Oct 2022
Topic Review
Non-Viral Delivery Systems
Non-viral delivery system simply refers to the use of non-viral vectors for drugs, genes or RNA delivery into cells. Non-viral vectors are safer, less toxic non-immunogenic alternatives to the viral vectors. They are easy to design, develop, and are inexpensive. 
  • 401
  • 21 Jan 2022
Topic Review
Non-Titania Based Semiconductor Hetero-Nanoarchitectures
Plasmonic photocatalysts combining metallic nanoparticles and semiconductors have been aimed as versatile alternatives to drive light-assisted catalytic chemical reactions beyond the ultraviolet (UV) regions, and overcome one of the major drawbacks of the most exploited photocatalysts (TiO2 or ZnO). The strong size and morphology dependence of metallic nanostructures to tune their visible to near-infrared (vis-NIR) light harvesting capabilities has been combined with the design of a wide variety of architectures for the semiconductor supports to promote the selective activity of specific crystallographic facets. The search for efficient heterojunctions has been subjected to numerous studies, especially those involving gold nanostructures and titania semiconductors. In the present review, we paid special attention to the most recent advances in the design of gold-semiconductor hetero-nanostructures including emerging metal oxides such as cerium oxide or copper oxide (CeO2 or Cu2O) or metal chalcogenides such as copper sulfide or cadmium sulfides (CuS or CdS). These alternative hybrid materials were thoroughly built in past years to target research fields of strong impact, such as solar energy conversion, water splitting, environmental chemistry, or nanomedicine.
  • 725
  • 15 Apr 2021
Topic Review
Non-Sieving Mechanism
Non-sieving mechanism is a particle removal process in which particles smaller than the membrane pores are captured by adsorption at the pore surface. The non-sieving mechanism plays an important role for charged solute. There are three accepted non-sieving mechanisms: Donnan exclusion, dielectric exclusion, and hydration mechanism.
  • 2.1K
  • 18 Feb 2022
Topic Review
Non-Road Mobile Machinery Emission Studies
The term Non-Road Mobile Machinery (NRMM) covers a broad range of machinery, with or without bodywork and wheels, that are installed with a combustion engine, either a spark ignition (SI) petrol engine or a combustion ignition (CI) diesel engine, and that are not intended for carrying passengers or goods on the road. The study of NRMM emissions in the literature has largely been overshadowed by their on-road counter parts due to data on NRMM not being as freely available.
  • 686
  • 20 Dec 2022
Topic Review
Non-Medical Applications of Chitosan Nanocomposite Coatings
Millions of tons of crustaceans are produced every year and consumed as protein-rich seafood but the shells and other non-edible parts constituting about half the body mass are wasted. The crustacean shells are a prominent source of polysaccharide (chitin) and protein. Chitosan, a de-acetylated form of chitin obtained from the crustacean waste are used for a variety of medical applications. In recent times, it has also found use in food and paint industries including marine antifouling coatings, due to its characteristic properties, like solubility in weak acids, film-forming ability, pH-sensitivity, antifouling properties, biodegradability, and biocompatibility. Chitosan composite coatings in food, paint and water treatment solutions have been developed. In food industries, chitosan-based composite films and coatings are applied for prolonging the post-harvest life of fruits and vegetables, while anti-corrosion and self-healing properties are mainly explored for antifouling applications in paints and metal ion chelation and antifouling properties are useful for water treatment.
  • 3.6K
  • 29 Oct 2020
Topic Review
Non-Ionic Surfactants
Surfactants are essential in the manufacture of polymeric nanoparticles by emulsion formation methods and to preserve the stability of carriers in liquid media. The deposition of non-ionic surfactants at the interface allows a considerable reduction of the globule of the emulsion with high biocompatibility and the possibility of oscillating the final sizes in a wide nanometric range.
  • 4.2K
  • 29 Jun 2021
Topic Review
Non-Intumescent Flame-Retardant Coating
Fire-retardant coatings, common materials for fire protection of buildings, are widely used in the construction industry. Because they do not change the nature of the matrix, while greatly improving the ability of the matrix to resist flame propagation, they significantly reduce the fire hazard of buildings. Flame-retardant coatings are divided into NIFRC and IFRC , depending on whether the flame-retardant coating expands when heated. NIFRCs are generally composed of inorganic materials that can prevent the return of the heat and oxygen supply to the combustible matrix during the heating process of the polymer and, at the same time, prevent the transfer of combustible gas generated by the pyrolysis of the matrix to the flame, thus protecting the polymer matrix. According to the literature reports, NIFRCs for RPUF mainly include hydrogel/sol, aerogel, ceramic materials, etc.
  • 681
  • 19 Apr 2023
Topic Review
Non-Helical Models of DNA Structure
In the history of molecular biology, non-helical or "side-by-side" models of DNA were proposed in the 1970s as a challenge to the standard double-helical model. The non-helical models attempted to solve problems relating to the topology of circular DNA chromosomes during replication. These theories were briefly considered seriously as a minority viewpoint, but they were later largely rejected due to X-ray crystallography of DNA duplexes and later the nucleosome core particle, as well as the discovery of topoisomerases, and these non-double-helical models are not currently accepted by the mainstream scientific community.
  • 1.0K
  • 12 May 2023
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