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Biogenic Synthesis of Nanoparticulate Materials for Antiviral Applications
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Kah Hon Leong, Jit Jang Ng, Lan Ching Sim, Pichiah Saravanan, Chaomeng Dai, Bo Tan
The chemical method has been found to be the most common technique in the synthesis of nanoparticles for antiviral agents. The chemical process involves the reduction of the precursor with the presence of energy. This technique requires the electrons to be transferred and reduced with the presence of a reducing agent. Various techniques use a chemical approach, including electrochemical, photochemical, microwave-assisted, and sonochemical. Using the chemical method in nanoparticles synthesis has been shown to result in a high yield with a controllable route. However, this process will cause environmental pollution due to the high usage of chemicals.
Using a Recombinant Metagenomic Lipase for Enantiomeric Separation of Pharmaceutically Important Drug Intermediates
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Rakesh Kumar, Uttam Chand Banerjee, Jagdeep Kaur
Enzymes are natural catalysts that facilitate the majority of the reactions occurring in biological systems. Use of natural catalysts (enzymes) for chemical processes is referred to as “white biotechnology” (Giovanni, 2003; Walsh, 2001). Natural catalysts are required in small amounts compared with chemical catalysts and can replace relatively dangerous chemicals and save resources (Jaeger, 2004; Patel, 2003; Panke et al., 2004). Currently, the biotechnological potential of hydrolytic enzymes is of special interest. Among these, lipases provide new and innovative biotechnological solutions, which in turn increase efficiency and productivity for manufacturers. They are a familiar valuable biocatalyst in food, pharmaceutical, detergent, and chemical industries. Lipase-catalyzed reactions have received much attention in recent years, as they successfully catalyze interesterification, acidolysis, esterification, alcoholysis, and aminolysis in addition to its hydrolytic activity on triglycerides (Guncheva et al., 2011; Kourist et al., 2010).
Chemistry and Isotopes of Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
Elements are those substances that are not resolved into simpler entities by chemical processes. The smallest amount of an element that participates in a chemical reaction is an atom. The components of an atom are the electron (charge — 1; mass 5.5 × 10-4), the proton (charge +1; mass 1), and the neutron (charge 0, mass 1). Protons and neutrons constitute the atomic nucleus. The number of protons in the nucleus gives the atomic number of the element and determines the identity of the atom as an element. The atomic number is given by a subscript preceding the abbreviation of the element, e.g., 53I. The properties of the elements are in periodic dependence on their atomic numbers. In the periodic table, the vertical arrangement of the elements is called a group (a total of 11) and the horizontal arrangement periods (7 altogether).
Bacterial surface attachment and fouling assay on polymer and carbon surfaces using Rheinheimera sp. identified using bacteria community analysis of brackish water
Published in Biofouling, 2022
Emily Manderfeld, Chidambaram Thamaraiselvan, Maurício Nunes Kleinberg, Lejla Jusufagic, Christopher J. Arnusch, Axel Rosenhahn
While short-time accumulation assays reveal an affinity of bacteria to a surface and initial bacteria attachment is influenced by surface roughness, topography, hydrodynamic conditions, and interfacial forces (Bernstein et al. 2014) this process is still reversible (Achinas et al. 2019). With the start of multiplication, EPS as a layer of protection for the bacteria is formed, forming a mushroom-like structure, allowing for nutrients to venture deep into the biofilm through water channels (Achinas et al. 2019). At this stage, a rapid increase in the population is observed. During this step, the contribution of physical and chemical processes during the initial adhesion end, and domination of biological processes is observed (Alotaibi et al. 2021). Therefore, the surfaces were challenged against the formation of a biofilm. Microscopy images shown in Figure 5 revealed the formation of a network-like structure on DDT as well as on PI with a denser network. PES showed the formation of an inhomogeneous network. Interestingly, LIG revealed a local biofilm formation and did not show a network on the surface. PS showed the formation of aggregates or microcolonies, which start to build a network-like structure. This morphology suggests that the biofilm will grow into a network over time. As expected from the short-term attachment assay, EG6 only showed a few colonies on the surface, probably due to the fact, that there were only a few bacteria that initially attached to the surface.
Evolution over time of mackinawite generated on carbon steel by the SRB metabolic activity: an in-operando Raman study
Published in Biofouling, 2022
H. Maaoui, V. Leblanc, H. Gueuné, Y. Guhel, B. Boudart
The transformation of iron sulphide is a complex physical and chemical process. It is reported that mackinawite is transformed into other phases over a wide range of temperature or pH via various oxidative pathways (Chiriţă et al. 2008). Oxidants such as H2S can induce the conversion to a more stable phase (pyrite or marcasite (FeS2)) (Krupp 1994; Benning et al. 2000). Previous studies investigated the oxidation of chemical synthetic mackinawite in the air at room temperature and in acidic anoxic solutions at 80 °C (Bourdoiseau et al. 2011). The oxidation of mackinawite by air can lead to the formation of greigite (Fe3S4) which is an intermediate phase formed during the oxidation process. In these conditions, mackinawite is first oxidised to Fe(III)-containing mackinawite which reacts with the sulphur element to form greigite. Finally, the formation of FeOOH phases from greigite is observed in the presence of oxygen. Boursiquot et al. also reported that dry oxidation of mackinawite induces the formation of greigite which is an intermediate reaction product before the appearance of sulphur and iron oxyhydroxides (Boursiquot et al. 2001). However, the formation of greigite via an oxidation of mackinawite in acidic anoxic solution starts with the appearance of Fe(III)-containing mackinawite and the increase in its Fe(III) content implies a structural rearrangement and consequently greigite is formed (Bourdoiseau et al. 2011).
Bioidentical hormones
Published in Climacteric, 2021
F. Z. Stanczyk, H. Matharu, S. A. Winer
Class B steroids are also found in nature but require chemical synthesis for use as therapeutic agents. For example, E2, progesterone and dehydroepiandrosterone (DHEA), which are widely used for postmenopausal HT, cannot be obtained from a natural source to be used therapeutically. Instead, they are synthesized chemically, primarily from a natural base material, most commonly from a plant source such as the Mexican yam and soybean. These plants contain steroids such as diosgenin and stigmasterol, which are used as precursors for the synthesis of a variety of steroids. Multiple chemical reactions in the laboratory (at least 15) are required to alter the base and obtain the desired steroid. Because the precursors used in this chemical process are obtained from a natural source, the process is considered biosynthetic.