Summary

Physics advocates research on unifying chemical bonds and recognized parallels on a different (and non-reductive) level, as per the concept of the Great Unification of Forces in Nature. From this perspective, a Physicochemical Grand Unification of Forces would be a worthy project for humankind in order to increase our undertanding of existence and to improve our lives. This entry collection aims to present an account of chemical bonds and interactions in nano- to maco-environments.

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Topic Review
Nitration of Proteins/Lipids/DNA by Peroxynitrite Derivatives
In recent years, much interest has been generated by the idea that nitrosative stress plays a role in the aetiology of human diseases, such as atherosclerosis, inflammation, cancer, and neurological diseases. The chemical changes mediated by reactive nitrogen species (RNS) are detrimental to cell function, because they can cause nitration, which can alter the structures of cellular proteins, DNA, and lipids, and hence, impair their normal function. One of the most potent biological nitrosative agents is peroxynitrite (ONOO−), which is produced when nitric oxide (•NO) and superoxide (•O2−) are combined at extremely rapid rates. Considering the plethora of oxidations by peroxynitrite, this makes peroxynitrite the most prevalent nitrating species responsible for protein, DNA, and lipids nitration in vivo. There is biochemical evidence to suggest that the interactions of the radicals NO and superoxide result in the formation of a redox system, which includes the reactions of nitrosation and nitration, and is a component of the complex cellular signalling network. However, the chemistry involved in the nitration process with peroxynitrite derivatives is poorly understood, particularly for biological molecules, such as DNA, proteins, and lipids.
  • 1.4K
  • 27 Sep 2022
Topic Review
Liquid Chromatography Separation Mechanism
Separation is a critical process to isolate a particular compound, whether it is a natural product or a synthetic product. Studies of a compound’s characteristics and elucidation structure provides reliable results for pure compounds because there is no interference from other compounds. The primary source of difficulty in a separation process is the high similarity between two or more compounds, such as racemic and homologous mixtures. Liquid chromatography has proven to be an effective solution to those problems. The key to liquid chromatography separation is a sustainable retention and elution process. Stationary phases are essential for separating compounds in liquid chromatography. Various liquid chromatography columns of both preparative and quantitative types have been used and continue to develop. This research will discuss the separation mechanism in liquid chromatography.
  • 1.4K
  • 02 Mar 2022
Topic Review
Catalytic Adsorptive Stripping Voltammetric Determination of Germanium
In organic free aqueous solutions, germanium is present in the form of Ge(OH)4 tetrahydroxide (pH < 7) or as H3GeO4−, which dominates in alkaline media (pH > 9). In the presence of many ligands containing carboxylic, di-orthophenolic, and polyalcoholic functional groups, Ge(IV) forms stable five-membered ring chelate complexes displaying coordination number 6.
  • 1.3K
  • 17 Feb 2022
Topic Review
Aerogel
Aerogels are one of the most interesting materials of the 21st century owing to their high porosity, low density, and large available surface area. Historically, aerogels have been used for highly efficient insulation and niche applications, such as interstellar particle capture. Recently, aerogels have made their way into the composite universe.
  • 2.6K
  • 14 Feb 2022
Topic Review
Metal-Organic Frameworks-Based Sensors for Food Safety
Metal-organic frameworks (MOFs) are a class of crystalline porous materials systems structured by using metals linked together by organic bridging ligands.
  • 1.8K
  • 09 Feb 2022
Topic Review
Hydrogen Storage Mechanism in Sodium-Based Graphene Nanoflakes
Carbon materials, such as graphene nanoflakes, carbon nanotubes, and fullerene, can be widely used to store hydrogen, and doping these materials with lithium (Li) generally increases their H2-storage densities. Unfortunately, Li is expensive; therefore, alternative metals are required to realize a hydrogen-based society. Sodium (Na) is an inexpensive element with chemical properties that are similar to those of lithium.
  • 930
  • 08 Feb 2022
Topic Review
Organosolv Lignin-Based Polyurethane
Polyurethanes (PUs) present an important class of polymers due to outstanding mechanical, chemical and physical properties. Thus, they find application in many industrial sectors in the form of flexible or rigid foams, coatings, adhesives, elastomers, thermoplasts or thermosets. Modern PU coating applications include self-healing coating films that can also be applied to rather rough surfaces, such as wood.
  • 1.6K
  • 22 Mar 2022
Topic Review
Vancomycin with Muramyl Pentapeptide
Vancomycin and a native muramyl pentapeptide ended with D-alanine (MPP-D-Ala), and vancomycin and a modified muramyl pentapeptide ended with D-serine (MPP-D-Ser) form complexes in a very specific way. This complexes provide a basis for characterizing the type and stability of the connection. The type of experimentally measured and computer-simulated interactions opens the field for discussion on possible modifications to the structure of vancomycin or muramyl pentapeptide to obtain their desired characteristics.
  • 1.7K
  • 07 Feb 2022
Topic Review
Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy
The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. 
  • 1.3K
  • 26 Jan 2022
Topic Review
Mechanochemistry in Portugal
In Portugal, publications with mechanochemical methods date back to 2009, with the report on mechanochemical strategies for the synthesis of metallopharmaceuticals. Since then, mechanochemical applications have grown in Portugal, spanning several fields, mainly crystal engineering and supramolecular chemistry, catalysis, and organic and inorganic chemistry.
  • 1.4K
  • 24 Jan 2022
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