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Fungal Influence on Hydrophobic Organic Pollutants Dynamics within the Soil Matrices
Published in Vivek Kumar, Rhizomicrobiome Dynamics in Bioremediation, 2021
Claire Baranger, Isabelle Pezron, Anne Le Goff, Antoine Fayeulle
Soil contaminants are subjected to a combination of chemical, physical and biological processes affecting their natural attenuation, persistence or transfer between different compartments. Volatile and relatively water-soluble compounds tend to have lower retention times in the soil since they either volatilize or leach into ground waters, potentially leading to an expansion of the contaminated area (Ortega–Calvo et al. 2013). Chemical or biological degradation of organic contaminants lowers the contamination levels by altering their chemical structure. This can lead to the release of metabolites with varying degrees of toxicity and bioavailability, or even to complete mineralization. As natural attenuation occurs, non-volatile hydrophobic pollutants with a high chemical stability tend to persist in soils in higher ratios than other compounds more easily removed through chemical or biological processes. As a result, the remaining fraction in aged contaminated soils is the least bioavailable (Ortega–Calvo et al. 2013).
Experimental Investigation of Carbonization Processes in the Formation of Foam-Based Epoxy Resin Containing Carbon Nanoparticles
Published in Alexander V. Vakhrushev, Omari V. Mukbaniani, Heru Susanto, Chemical Technology and Informatics in Chemistry with Applications, 2019
S. G. Shuklin, D. S. Shuklin, A. V. Vakhrushev
The physical and chemical structure of the surface of materials determines many practically important macroscopic properties of materials and products. It is important to take into account that the mechanical transfer of the characteristics of the volume of materials under study to the properties of their surface may lead to a misunderstanding of the phenomena occurring at the interface. Even with respect to such relatively simple systems as inorganic crystals, judging the properties of their surface layers by extrapolating the volume characteristics is not always correct. It is known that the adsorption properties of various crystalline faces can vary greatly.16 Especially, the peculiarities of the structure of surface layers should be taken into account when studying such complex objects as polymeric materials and biological systems.
Restoring Credibility to Natural Materials
Published in Graham A. Ormondroyd, Angela F. Morris, Designing with Natural Materials, 2018
The physical properties of any material are determined by its chemical structure. Wood contains an abundance of chemical groups called ‘free hydroxyls’. Free hydroxyl groups absorb and release water according to changes in the climatic conditions to which the wood is exposed. This is the main reason why wood swells, shrinks and decays.
Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics
Published in Critical Reviews in Environmental Science and Technology, 2022
Tomer Malchi, Sara Eyal, Henryk Czosnek, Moshe Shenker, Benny Chefetz
Drugs generally do not create a new effect, but rather, activate or inhibit a specific receptor-related activity. Receptors are sites to which specific ligands bind, thereby altering the cell's biochemical activity. An agonist binds to a receptor and activates a sequence of events that leads to a response. An antagonist binds to a receptor to inhibit the action, without initiating any effect itself. Drugs conferring a short duration of receptor activation generally interact via weaker bonds (ionic, hydrogen or van der Waals), whereas long-duration or irreversible drug–receptor interactions may form stronger bonds, such as covalent bonds. A drug’s ability to affect a specific receptor is related to its affinity and efficacy, which are parameters determined by its chemical structure. Affinity is defined as the probability of a drug occupying its target receptor upon interaction. Efficacy is defined as the extent to which a drug activates a receptor, resulting in a cellular response also known as drug effect (Buxton & Benet, 2013; Page & Maddison, 2008; Raj & Raveendran, 2019).
The sustainability of adobe construction: past to future
Published in International Journal of Architectural Heritage, 2019
Cristiana Costa, Ângela Cerqueira, Fernando Rocha, Ana Velosa
Other sustainable materials have been studied as potential resources for rehabilitation and even for the construction of new buildings, in particular geopolymers. A geopolymer is an inorganic polymer, obtained by the alkaline activation of an aluminosilicate, under certain temperature and pressure conditions (Davidovits 2002). Its properties depend mainly on the chemical structure. In addition to the replacement of cements, these products can also be applied as other materials, such as composites with fire-resistant fibers, bricks, anti-fire protection, in the ceramic industry, encapsulation of toxic and radioactive waste, among others. Geopolymers can be produced from naturally high-strength natural phyllosilicates being cured at room temperature. As such, they have good physicochemical characteristics, such as: high workability, fast hardening, surface finish, rapid development of mechanical strength, surface hardness, good chemical resistance, and heat and fire resistance (Davidovits 2015). These characteristics reveal the great potential for application in construction materials. Geopolymers will contribute decisively to increase sustainability in the construction industry, because, compared to traditional cement, they have the advantage of reducing CO2 emissions, as well as lower energy embodiment when compared to the high energy consumed during the production of clinker in a traditional cement.
Studying some networks using topological descriptors and multi-criterion decision making
Published in Molecular Physics, 2023
Guoping Zhang, Arfa Mushtaq, Adnan Aslam, Saima Parveen, Salma Kanwal
Chemical graph theory is a branch of mathematics that combines chemistry and graph theory. It is used to mathematically model molecules in order to obtain awareness about the physical properties of the chemical compound. Chemical structure is a depiction of the structural formula of a chemical compound in terms of graph postulations. Silicate and oxide networks have much importance in chemistry. The fundamental block of all the silicate mineral structures is the silicon-oxygen tetrahedron , where is at the centre and is at each vertex. Each is shared between two such tetrahedron and forms the formula . Thus, in has a network structure that is very difficult to dissociate due to the higher number of bonds. In addition to this, connection is one of the strongest inorganic connections due to similarity in atomic sizes and back bonding. All these contribute to a very stable network that demands a lot of energy to melt, making the melting point very high. Such networks include oxide, dominating oxide, triangular silicate and dominating silicate networks, etc. Topological indices are numerical number associated with a molecular structure and may be helpful to predict their physical. In the past two decades, many topological invariants have been proposed and used in theoretical chemistry, toxicology and pharmacology for correlation analysis.