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Environmental Toxins
Published in Gia Merlo, Kathy Berra, Lifestyle Nursing, 2023
Ozone (O3) is a highly reactive gas composed of three oxygen atoms. Ozone occurs naturally in the environment but can also be a man-made product that has adverse effects on human health. Stratospheric ozone occurs naturally and reduces the amount of harmful ultraviolet radiation that reaches the Earth’s surface. Ground level ozone is formed from man-made processes and is able to be inhaled by humans. Ground level ozone is mainly formed from photochemical reactions between two major classes of air pollutants, volatile organic compounds (VOC) and nitrogen oxides. Significant sources of VOC in the environment are chemical plants, gasoline pumps, and autobody shops. Nitrogen oxides result primarily from high temperature combustion from sources such as power plants, industrial furnaces and boilers, and motor vehicles (EPA, 2021a).
Additional Techniques for Designing and Representing Structures of Large Molecules
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
Step (5): Condensation through step (4) often provides the most useful description of the molecule; further condensation is possible. Bond lines from carbon to oxygen can be eliminated. For double bonded oxygens, which are not drawn in the line of the carbon chain atoms, place the oxygen atom symbol on the same line as the carbons, to the right and next to the carbon (or carbon-hydrogen group) to which it is bonded. Note that the format (CH3COCH2Br) cannot mean that the oxygen is part of the carbon chain such as (H3C—C—O—CH2Br). Although the oxygen has two bonds in this incorrect reconstruction, the second carbon has only two bonds and, thus, cannot be correct. The condensed format can only be regenerated to the original molecule; no information is lost.
Foreword
Published in Richard L. Hilderbrand, The Role of Phosphonates in Living Systems, 2018
All phosphorus accessible to living organisms occurs in phosphate minerals as orthophosphates. The phosphorus atom occurs at the + 5 level of oxidation with four oxygen atoms bonded to the phosphorus in a tetrahedral structure. The organophosphates which occur naturally in a living system are usually oxygen esters, diesters, or anhydrides of phosphoric acid. There are rather infrequent exceptions to this bonding of phosphates in living systems. One exception is the natural occurrence of the carbon to phosphorus (C–P) bond in the phosphonate class of organophosphates. Although phosphate had long been recognized as crucial to life processes, it was not until 1947 that Chavane,2 a chemist involved in synthesizing phosphonates, observed that, since the C–P bond was stable, there was a possibility for the occurrence of phosphonates in nature. The actual identification of a naturally occurring phosphonate finally came in 1959 by Horiguchi and Kandatsu,3 who identified 2-aminoethylphosphonic acid (AEP) in an amino acid extract from an hydrolysate of rumen protozoal lipid. Phosphonates have subsequently been shown to occur naturally in a variety of organisms and several metabolic processes involving phosphonates have been elucidated.
Review on Chemistry of Oxazole derivatives: Current to Future Therapeutic Prospective
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Sweta Joshi, Meenakshi Mehra, Ramandeep Singh, Satinder Kakar
In 1962 oxazole entity was firstly synthesized, but the chemistry of oxazole established. In past 1876 by synthesizing 2-methyl oxazole. In the beginning of the First World War oxazole entity came into prominence, when penicillin antibiotic was invented. During the invention of dienes in the Diels Alder reaction a new beginning of oxazole chemistry will occur. Oxazole has 3 carbon, 1 nitrogen and 1 oxygen atoms. These all are sp2 hybridized and planar. The atoms also contains unhybridized p orbital which is perpendicular to the plane of σ bonds. Totally six non-bonding electrons are present, out of which 3 are of carbon 1 from nitrogen and 2 of oxygen (Figure 2). So oxygen atom is highly electronegative, thus the delocalization is not overly effective [6].
In vitro and in silico studies on clinically important enzymes inhibitory activities of flavonoids isolated from Euphorbia pulcherrima
Published in Annals of Medicine, 2022
Abdur Rauf, Muslim Raza, Muhammad Humayun Khan, Hassan A. Hemeg, Yahya S. Al-Awthan, Omar Bahattab, Sami Bawazeer, Saima Naz, Faika Basoglu, Muhammad Saleem, Majid Khan, Hosseini Seyyedamirhossein, Mohammad S. Mubarak, Ilkay Erdogan Orhan
Compounds 1 and 2 have MlogP values of −0.415 and −0.327, respectively, indicating that they should be easily absorbed. Similarly, these molecules have the potential to make H-bonding with the receptor as determined by the topological polar surface area (TPSA) score. TPSA ratings for compounds 1 and 2 are 144.52 and 137.43, respectively. Formation of additional hydrogen bonds is due to the presence of numerous nitrogen and oxygen atoms. Thus, the present investigation showed that compounds 1 and 2 are hydrophilic due to strong hydrogen bonding and high TPSA score, based on the binding affinity and adsorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics. Furthermore, analysis of the ADMET characteristics for compounds 1 and 2 shows that they have strong drug-like qualities, which opens the door for further optimization of the compounds under investigation.
In vitro and in silico study of mixtures cytotoxicity of metal oxide nanoparticles to Escherichia coli: a mechanistic approach
Published in Nanotoxicology, 2022
Supratik Kar, Kavitha Pathakoti, Danuta Leszczynska, Paul B. Tchounwou, Jerzy Leszczynski
The developed mixture QSAR models can overcome the constraint of previous QSAR models built with single MONPs based on the wrongful assumption that in most cases MONPs exist in nature as single entities. On contrary, most of them are found as chemical mixtures. Therefore, our developed models can predict the untested and newly developed mixture MONPs considering the applicability domain aspect. Along with the prediction purpose, we firmly confirmed that each MONP acts through ‘Independent action’ in mixtures to induce cytotoxicity to E. coli instead of inducing an additive, synergistic or antagonistic interaction among MONPs. The total metal electronegativity in a specific metal oxide relative to the number of oxygen atoms (E. coli. The associated features are critical for understanding the mechanisms of cytotoxicity to E. coli and for predicting the potential environmental risk associated with single and mixture MONPs. The created models can be exploited for environmental risk assessment of any untested single as well as binary and tertiary MONPs mixtures to E. coli, hence offering a scientific basis for designing and preparing safe and effective MONP mixtures.