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Anaerobic digestion is a complex biochemical process that is represented by the stoichiometric Buswell's equation. Buswell's equation is the study of the interface among biochemistry, mathematics, and chemistry. Students often have difficulty in understanding the nature of biochemical stoichiometry. Buswell's equation is significant for the calculation of the quantity of biomethane. Although the general formula CxHyOz of organic pure substance or mixture has been well studied, the Buswell's equation for biomolecules containing phosphorous has rarely been explored. The aim of this article is to study the nature of Buswell's equation using the H-atom method. The new general Buswell's equation, which contains phosphorous, is deduced from the H-atom and algebraic methods.

ABSTRACT: Understanding the characteristics of bacteriophages is crucial for the optimization of phage therapy. In this study, the biological and genomic characteristics of coliphage LHE83 were determined and its synergistic effects with different types of antibiotics against E. coli E82 were investigated. Phage LHE83 displayed a contractile tail morphology and had a titer of 3.02 × 109 pfu/mL at an optimal MOI of 0.01. Meanwhile, phage LHE83 exhibited good physical and chemical factors tolerance. The 1-step growth analysis revealed a latent period of approx. 10 min with a burst size of 87 pfu/infected cell. Phage LHE83 belongs to the genus Dhakavirus. Its genome consists of 170,464 bp with a 40% GC content, and a total of 268 Open Reading Frames (ORF) were predicted with no detected virulent or resistant genes. ORF 213 was predicted to encode the receptor binding protein (RBP) and confirmed by the antibody-blocking assay. Furthermore, a phage-resistant strain E. coli E82R was generated by co-culturing phage LHE83 with E. coli E82. Genomic analysis revealed that OmpA served as the receptor for phage LHE83, which was further confirmed by phage adsorption assay using E. coli BL21ΔOmpA, E. coli BL21ΔOmpA: OmpA and E. coli BL21:OmpA strains. Additionally, a synergistic effect was observed between phage LHE83 and spectinomycin against the drug-resistant strain E. coli E82. These results provide a theoretical basis for understanding the interactions between phages, antibiotics, and host bacteria, which can assist in the clinical application of phages and antibiotics against drug-resistant bacteria.

Oxidation number (ON) is taught as an electron-counting concept for redox reactions in chemistry curriculum. The molecular formula method, the Lewis formula method, and the structural formula method have all been used to determine ON. However, the task of assigning ON still poses problems for some teachers and students. This paper explores a new method, the fragmentation method, which is a visual approach for counting the individual ON of any atom according to its structural formula. The critical step is to break the carbon-heteroatom bond into organic fragments and inorganic fragments. The individual ON of carbon atoms and heteroatoms can be determined by the bond cleavages in the organic and biological compounds. The mean ON of carbons can be calculated by the arithmetic mean of all individual ON of carbons in a molecule or molecular ion. The step-by-step operating procedures and examples are provided. When comparing corresponding molecules in organic conversions, the change of individual ON of atoms can be used as a tool for determining the number of transferred electrons. Furthermore, a reaction site can be identified by their changes of individual ON, chemical composition, and bond order in metabolic redox reactions.

Redox reaction is a core concept in teaching and learning chemistry. This article explores a new method for balancing organic redox reactions that requires the balancing of both atoms and charges. The H+, O, H[subscript 2]O, and e- are used as balanced vehicles in two half reactions. A non-oxidation number approach can be applied to both molecular and ionic equations. The article also provides standard operating procedures and examples. The number of transferred electrons is first determined by balancing a half redox reaction; consequently; the change of oxidation numbers can be calculated. The mathematical equation of Te- = n Te- = n [delta] ON is established, and the change of oxidation numbers ([delta]ON) can be counted by the number of transferred electrons (Te-) and the number of atoms with oxidation numbers change (n). By using this mathematical equation as a new approach, students can conveniently calculate the change of mean oxidation numbers for an assigned atom in a half redox reaction.

The oxidation number and number of transferred electrons are two paramount parameters in the study of redox reactions. Their calculations are both important and challenging. The oxidation number of organic carbons is used in organic chemistry, biochemistry, and applied chemistry. Combustion reaction is a classical type of redox reaction, in which the oxygen molecule (O2) is the oxidizing agent. In this article, the integration of three sets of relations is explored by using the method of balancing organic combustion: (i) number of transferred electrons and oxidation number of organic carbons, (ii) mole of oxygen molecule and number of transferred electrons, and (iii) oxidative ratio, oxidation number of organic carbons, and number of transferred electrons. This method can also establish the relationships among the stoichiometric coefficients, mole of oxygen molecule, oxidative ratio, number of transferred electrons, and oxidation number of organic carbons. Furthermore, the oxidation number of organic carbons and the number of transferred electrons of a given organic compound can be determined by the derived mathematical equations.

The formation mechanism of MnS inclusions during heat treatment and its effect on the pitting behavior of laser powder bed fusion (L-PBF)-fabricated 316L stainless steel (SS) were investigated. MnS inclusions precipitated at the grain boundaries of the samples, and the spherical oxide particles can become nucleation sites. The quantity and size of the MnS inclusions increased with prolonged heating. Compared with the as-received sample, the pitting of heat-treated L-PBF-fabricated 316L SS samples was mainly induced by the newly generated MnS inclusions rather than the fabricated gas pores and extended along the grain boundaries; this caused the dramatic pitting resistance deterioration.

A novel device is constructed to study the localized corrosion susceptibility of 2024 aluminum alloy at a dynamic seawater/air interface. Corrosion in three distinct regions are identified: full immersion region, seawater/air interfacial region (alternant wet/dry region), and atmosphere region. The corrosion process in the interfacial region over time was studied by EIS and the corrosion product was characterized by SEM. Experimental results revealed that, a layer of intense and uniform corrosion product was formed on the seawater/air interfacial region, due to the oxygen enrichment in that region. Pitting corrosion was more severe in the full immersion region than that in the seawater/air interface, as verified by a lower charge transfer resistance and more severe pitting corrosion and intergranular corrosion extent.

Defining and balancing redox reaction requires both chemical knowledge and mathematical skills. The prevalent approach is to use the concept of oxidation number to determine the number of transferred electrons. However, the task of calculating oxidation numbers is often challenging. In this article, the H-atom method and O-atom method are developed for balancing redox equations. These two methods are based on the definition of redox reaction, which is the gain and loss of hydrogen or oxygen atoms. They complement current practices and provide an alternate path to balance redox equations. The advantage of these methods is that calculation of oxidation number is not required. Atoms are balanced instead. By following standard operating procedures, H-atom, O-atom, and H2O molecule act as artificial devices to balance both inorganic and organic equations in molecular forms. By using the H-atom and O-atom methods, the number of transferred electrons can be determined by the number of transferred H-atoms or O-atoms, which are demonstrated as electron-counting concepts for balancing redox reactions. In addition, the relationships among the number of transferred H-atom, the number of transferred O-atom, the number of transferred electrons, and the change of oxidation numbers are established.

Combustion reactions, stoichiometry, and redox reactions are some of the basic contents in chemistry curriculum. Although the counting of transferred electrons is critical in redox reactions, assigning mean oxidation number of organic carbons (ONc) is not always easy. Even though the relationship between the oxidative ratio (OR) and ONc is known, the relationship between the number of transferred electrons (Te−) and OR has not been thoroughly studied. The H-atom method has already been developed to balance and deduct organic combustion reactions. It can be used further to help establish the relationships among the stoichiometric coefficients (SC), the number of transferred hydrogens (TH), and Te−. This article uses the procedures of the H-atom method for balancing and deducting, and the known relationships among SC, TH, and Te− for exploring the relationships among SC, Te−, ONc, and OR in organic combustion reactions. By integrating three sets of relationships: (i) SC and Te−, (ii) Te− and ON, and (iii) SC and OR, the interconversions among SC, Te−, ONc, and OR can be mathematically formulated. Furthermore, Te−, ONc, and OR can be assigned by SC and the general molecular formula of CxHyOzXw.