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Topic Review
Gas Hydrate Technology
Innovating methods for treating industrial wastewater containing heavy metals frequently incorporate toxicity-reduction technologies to keep up with regulatory requirements. This research reviews the latest advances, benefits, opportunities and drawbacks of several heavy metal removal treatment systems for industrial wastewater in detail. The conventional physicochemical techniques used in heavy metal removal processes with their advantages and limitations are evaluated. A particular focus is given to innovative gas hydrate-based separation of heavy metals from industrial effluent with their comparison, advantages and limitations in the direction of commercialization as well as prospective remedies. Clathrate hydrate-based removal is a potential technology for the treatment of metal-contaminated wastewater. In this research, a complete assessment of the literature is addressed based on removal efficiency, enrichment factor and water recovery, utilizing the gas hydrate approach. It is shown that gas hydrate-based treatment technology may be the way of the future for water management purposes, as the industrial treated water may be utilized for process industries, watering, irrigation and be safe to drink. 
  • 1.5K
  • 15 Apr 2022
Topic Review
Structure, Spectral Properties and Chemistry of Spiropyrans
Spiropyrans (SP) are a well-studied class of photochromic compounds. These compounds are usually named in conformity with the IUPAC rules for nomenclature of heterocyclic spirocompounds, as derivatives of 1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-indoline] or 1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-indole].
  • 1.5K
  • 11 Jul 2023
Topic Review
A Labile Metallo-Porphyrin as Tool to Control J-Aggregates Chiroptical Properties
The zinc(II) metal derivative of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) is quite labile and readily demetallates under acidic conditions, affording the parent diacid porphyrin in a monomeric form. The rate of this process is first order on [ZnTPPS4] and second order on [H+], allowing a precise control of the monomer release in solution. Under high ionic strength, this latter species is able to self-assemble into J-aggregates, whose kinetics of growth are largely modulated by pH. The aggregation kinetics have been treated according to a well-established model, in which the formation of an initial nucleus is the rate determining step preceding the autocatalytic growth of the whole assembly. The extinction spectra of the aggregates suggest the occurrence of a dipolar coupling mechanism very similar to that operating in metal nanoparticles. Spontaneous symmetry breaking takes place in these aggregates as evidenced by unusual circular dichroism spectra. The intensity and sign of the effect is controlled by the aggregation rate and therefore can be tuned through a proper choice of initial conditions.
  • 1.4K
  • 15 Jul 2020
Topic Review
2-Oxocarboxylic Acids
Atmospheric organic aerosols play a major role in climate, demanding a better understanding of their formation mechanisms by contributing multiphase chemical reactions with the participation of water. The sunlight driven aqueous photochemistry of small 2-oxocarboxylic acids is a potential major source of organic aerosol, which prompted the investigations into the mechanisms of glyoxylic acid and pyruvic acid photochemistry reviewed here. While 2-oxocarboxylic acids can be contained or directly created in the particles, the majorities of these abundant and available molecules are in the gas phase and must first undergo the surface uptake process to react in, and on the surface, of aqueous particles.
  • 1.4K
  • 02 Jul 2023
Topic Review
Application of Quantum Mechanics/Molecular Mechanics Methodologies to Metalloproteins
The multiscaling quantum mechanics/molecular mechanics (QM/MM) approach was introduced in 1976, while the extensive acceptance of this methodology started in the 1990s. The combination of QM/MM approach with molecular dynamics (MD) simulation, otherwise known as the QM/MM/MD approach, is a powerful and promising tool for the investigation of chemical reactions’ mechanism of complex molecular systems, drug delivery, properties of molecular devices, organic electronics, etc. Applications of the QM/MM methodologies on metalloproteins are presented.  
  • 1.4K
  • 05 May 2022
Topic Review
Protection of Iron by Corrosion Inhibitors
Iron is a widely used metal due to its low cost and availability, but it is susceptible to corrosion in many circumstances. This corrosion can result in economic and environmental losses, and negatively affect the physical and chemical properties of the metal.
  • 1.4K
  • 24 Mar 2023
Topic Review
Nitrogenase
Nitrogenase defines the familty of enzymes that catalyze the reduction of N2 (molecular nitrogen) to NH3 (ammonia). It is the only enzyme family which can realize this process of nitrogen fization. 
  • 1.3K
  • 19 Feb 2021
Topic Review
Functional Materials for Wearable Sensors
With the recent development of flexible electronic materials, smart transducers, and wireless systems, wearable sensor technology has gained significant interest in the realization of personalized medical care. The design and development of flexible/stretchable dry electrodes with good adherence to biological tissues is in great demand due to the complex attributes of the human body. However, the major difficulty is finding the appropriate materials with good flexibility and conductivity, although some other relevant features such as bio-compatibility, durability, weight, size, etc.
  • 1.3K
  • 05 Sep 2022
Topic Review
Thermal Analysis to 3D Printing
Thermal analysis (TA) comprises various measuring techniques with a common feature: the measure of the material response when heated or cooled (or, in some cases, held isothermally).
  • 1.2K
  • 29 Mar 2022
Topic Review
Supramolecular Aggregates
Supramolecular Aggregates cross several disciplines, embracing the sciences of nature and joining theory, experiment, and application, from molecular to macroscopic levels. The problems of interdisciplinarity are overcome initially with scientific divulgation, bringing concepts from their origin, to facilitate the access of young scientists to the scientific content. Next, focus on some basic principles can help to understand the non trivial connections between Physics, Chemistry and Biology. 
  • 1.2K
  • 03 Aug 2021
Topic Review
Geant4-DNA Modeling of Water Radiolysis
In this work, we use the next sub-volume method (NSM) to investigate the possibility of using the compartment-based (“on-lattice”) model to simulate water radiolysis.
  • 1.2K
  • 24 Jun 2021
Topic Review
Steady State
In chemistry, a steady state is a situation in which all state variables are constant in spite of ongoing processes that strive to change them. For an entire system to be at steady state, i.e. for all state variables of a system to be constant, there must be a flow through the system (compare mass balance). A simple example of such a system is the case of a bathtub with the tap running but with the drain unplugged: after a certain time, the water flows in and out at the same rate, so the water level (the state variable Volume) stabilizes and the system is in a steady state. The steady state concept is different from chemical equilibrium. Although both may create a situation where a concentration does not change, in a system at chemical equilibrium, the net reaction rate is zero (products transform into reactants at the same rate as reactants transform into products), while no such limitation exists in the steady state concept. Indeed, there does not have to be a reaction at all for a steady state to develop. The term steady state is also used to describe a situation where some, but not all, of the state variables of a system are constant. For such a steady state to develop, the system does not have to be a flow system. Therefore, such a steady state can develop in a closed system where a series of chemical reactions take place. Literature in chemical kinetics usually refers to this case, calling it steady state approximation. In simple systems the steady state is approached by state variables gradually decreasing or increasing until they reach their steady state value. In more complex systems state variable might fluctuate around the theoretical steady state either forever (a limit cycle) or gradually coming closer and closer. It theoretically takes an infinite time to reach steady state, just as it takes an infinite time to reach chemical equilibrium. Both concepts are, however, frequently used approximations because of the substantial mathematical simplifications these concepts offer. Whether or not these concepts can be used depends on the error the underlying assumptions introduce. So, even though a steady state, from a theoretical point of view, requires constant drivers (e.g. constant inflow rate and constant concentrations in the inflow), the error introduced by assuming steady state for a system with non-constant drivers may be negligible if the steady state is approached fast enough (relatively speaking).
  • 1.2K
  • 14 Oct 2022
Topic Review
Corrosion Inhibition of Metal Surfaces Mediated by 1,2,3-Triazoles
Corrosion is generally viewed as the destructive consequence of chemical reaction between a metal or metal alloy and its environment that contains corrosive agents. Compared to inorganic corrosion inhibitors, the organic ones are less toxic, can be also used at low concentrations, and have a better film-forming ability. The adsorption properties of organic corrosion inhibitors are primarily linked to the presence of both π-electrons from aromatic rings and heteroatoms in the molecular structures. Indeed, organic compounds containing nitrogen, phosphorus, sulfur, and oxygen atoms have been extensively investigated as corrosion inhibitors of metals and their alloys in acidic environments. In this respect, triazole derivatives are the most used nitrogen-containing organic inhibitors, in particular the family of 1,2,3-triazoles prepared under click chemistry regime by the prolific copper-catalyzed azide cycloaddition reactions. 
  • 1.2K
  • 10 Feb 2022
Topic Review
Applications of g-C3N4-Based Photocatalysts
The assembly of g-C3N4 with metal oxides is an effective strategy which can not only improve electron–hole separation efficiency by forming a polymer–inorganic heterojunction, but also compensate for the redox capabilities of g-C3N4 owing to the varied oxidation states of metal ions, enhancing its photocatalytic performance. Applications of g-C3N4-based materials in photocatalysis are discussed, including water splitting to generate H2 and O2, the degradation of pollutants, CO2 reduction and bacterial disinfection.
  • 1.2K
  • 29 Nov 2022
Topic Review
Ignition of Fires from Electrical Causes
In a number of countries, somewhere around 20% of reported building fires are due to electrical faults or failures. There can be a number of mechanisms responsible, but arcing in air and hot-surface ignitions of combustible materials are important causes. Details of these two mechanisms are reviewed. It is shown that even though arcing in air produces temperatures greatly higher than the ignition temperature of any ignitable solid, this does not always result in ignition. With regards to ignitions from hot surfaces or objects, it is shown that the area of the hot object presented to the ignitable material is a crucial variable.
  • 1.1K
  • 10 Aug 2023
Topic Review
The Design of Ni-Based Single Crystal Superalloys
The most important performance characteristics of heat-resistant alloys (HRAs) are creep and fatigue resistance, which are very complex functions of chemical composition and microstructure. The microstructure of metal HRAs, among which the first place is occupied by Ni-based alloys, usually consists of two main phases: a solid solution based on the main element containing alloying elements (matrix), and a strengthening phase, which is usually used as intermetallides, carbides and silicides.
  • 1.1K
  • 17 Jan 2022
Topic Review
Graphitic Carbon Nitride as a Photocatalyst
Carbon nitride, albeit known for a long time, has been tested as a photocatalyst only since 2009. Extensive searches for reliable visible-light-activated semiconductor photocatalysts revealed the next generation photocatalyst based on a polymeric semiconductor—graphitic carbon nitride.
  • 1.1K
  • 29 Dec 2022
Topic Review
Metamaterials for Device Applications
Metamaterials are the major type of artificially engineered materials which exhibit naturally unobtainable properties according to how their microarchitectures are engineered. Owing to their unique and controllable effective properties, including electric permittivity and magnetic permeability, the metamaterials play a vital role in the development of meta-devices.
  • 1.0K
  • 12 May 2021
Topic Review
Mesoporous Silica Nanoparticles
Mesoporous silica nanoparticles (MSNs) have been widely employed as drug carriers owing to their exquisite physico-chemical properties. Mesoporous material Solid and porous material, with natural or synthetic character, with an average pore size between microporous (less than 2 nm) and macroporous (more than 50 nm). The pore structure can be ordered or not and provides an extremely high surface area in a relatively small amount of material According to IUPAC notation, the mesoporous category is midway between the pore sizes that define microporous materials, up to 2 nm, and macroporous, pore diameters greater than 50 nm. They have a large number of applications in the fields of catalysis, molecular separation, drug release or chemical sensors among others, as a result of the network of porous cavities in their internal structure. - Examples: ordered mesoporous silica materials, carbon molecular sieves, porous organic / inorganic hybrid materials and porous metal oxides.
  • 1.0K
  • 13 Jan 2021
Topic Review
Indomethacin Increases HSA-Quercetin Binding
Human serum albumin (HSA) is the most abundant carrier protein in the human body. Competition for the same binding site between different ligands can lead to an increased active concentration or a faster elimination of one or both ligands. Indomethacin and quercetin both bind to the binding site located in the IIA subdomain. To determine the nature of the HSA-indomethacin-quercetin interactions, spectrofluorometric, docking, molecular dynamics studies, and quantum chemical calculations were performed. The results show that the indomethacin and quercetin binding sites do not overlap. Moreover, the presence of quercetin does not influence the binding constant and position of indomethacin in the pocket. However, binding of quercetin is much more favorable in the presence of indomethacin, with its position and interactions with HSA significantly changed. These results provide a new insight into drug-drug interactions, which can be important in situations when displacement from HSA or other proteins is undesirable or even desirable. This principle could also be used to deliberately prolong or shorten the xenobiotics' half-life in the body, depending on the desired outcomes.
  • 1.0K
  • 06 Nov 2020
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