Computing Topological Descriptors and Polynomials of Certain 2D Chemical Structures

In the fields of mathematical chemistry, a topological index, also known as a connectivity index, is a type of a molecular descriptor that is calculated based on the molecular graph of a chemical compound. Topological indices are an analytical framework of a graph which portray its topology and are mostly equal graphs. Topological indices (TIs) are numeral quantities that are used to foresee the natural correlation among the physicochemical properties of the chemical compounds in their fundamental network. TIs show an essential role in the theoretical abstract and environmental chemistry and pharmacology. In this paper, we compute many latest developed degree-based TIs. An analogy among the computed different versions of the TIs with the help of the numerical values and their graphs is also included .In this article, we compute the first Zagreb index, second Zagreb index, hyper Zagreb index, ABC Index, GA Index, and first Zagreb polynomial and second Zagreb polynomial of chemical graphs polythiophene, nylon 6,6, and the backbone structure of DNA.

Hydrogen Peroxide in Ecological and Environmental Chemistry

This review paper is focused on the detailed consideration of the structure, properties and reactions of H2O2. The paper highlights the importance of revealing these processes’ mechanisms, since they have been insufficiently studied so far, or the related data have a fragmentary and incomplete character. A special attention is given to catalytic oxidation reactions, formation and properties of intermediates, their role in the natural environment.

Simultaneous Infrared Spectroscopy, Raman Spectroscopy and Luminescence Sensing: A Multi-Spectroscopic Analyti-cal Platform

Scientific questions in fields such as catalysis, monitoring of biological processes or environmental chemistry demand for analytical technologies combining orthogonal spectroscopies. Combined spectroscopic concepts facilitate in-situ on-line monitoring of dynamic processes providing for a better understanding of the involved reaction pathways. In the present study, a low-liquid-volume multi-spectroscopic platform was developed based on infrared attenuated total reflection (IR-ATR) spectroscopy combined with Raman spectroscopy and lumines-cence sensing. For demonstrating the measurement capabilities, exemplary analyte systems including water / heavy water and aqueous solutions of ammonium sulfate were analyzed as proof-of-principle studies. It was successfully demonstrated that three optical techniques may be integrated into a single analytical platform with-out interference providing synchronized and complementary datasets by probing the same minute sample vol-ume. In addition, the developed assembly provides a gas-tight lid sealing the headspace above the probed liq-uid for monitoring the concentration of molecular oxygen also in the gas phase via luminescence quenching. Hence, the entire assembly may be operated at inert conditions, as required for example during the analysis of photocatalytic processes.

DeepCarc: Deep Learning-Powered Carcinogenicity Prediction Using Model-Level Representation

Carcinogenicity testing plays an essential role in identifying carcinogens in environmental chemistry and drug development. However, it is a time-consuming and label-intensive process to evaluate the carcinogenic potency with conventional 2-years rodent animal studies. Thus, there is an urgent need for alternative approaches to providing reliable and robust assessments on carcinogenicity. In this study, we proposed a DeepCarc model to predict carcinogenicity for small molecules using deep learning-based model-level representations. The DeepCarc Model was developed using a data set of 692 compounds and evaluated on a test set containing 171 compounds in the National Center for Toxicological Research liver cancer database (NCTRlcdb). As a result, the proposed DeepCarc model yielded a Matthews correlation coefficient (MCC) of 0.432 for the test set, outperforming four advanced deep learning (DL) powered quantitative structure-activity relationship (QSAR) models with an average improvement rate of 37%. Furthermore, the DeepCarc model was also employed to screen the carcinogenicity potential of the compounds from both DrugBank and Tox21. Altogether, the proposed DeepCarc model could serve as an early detection tool (https://github.com/TingLi2016/DeepCarc) for carcinogenicity assessment.

On the Study of Reverse Degree-Based Topological Properties for the Third Type of p th Chain Hex-Derived Network

Vertices and edges are made from a network, with the degree of a vertex referring to the number of connected edges. The chance of every vertex possessing a given degree is represented by a network’s degree appropriation, which reveals important global network characteristics. Many fields, including sociology, public health, business, medicine, engineering, computer science, and basic sciences, use network theory. Logistical networks, gene regulatory networks, metabolic networks, social networks, and driven networks are some of the most significant networks. In physical, theoretical, and environmental chemistry, a topological index is a numerical value assigned to a molecular structure/network that is used for correlation analysis. Hexagonal networks of dimension t are used to build hex-derived networks, which have a wide range of applications in computer science, medicine, and engineering. For the third type of hex-derived networks, topological indices of reverse degree based are discussed in this study.

Feature Paper in Environmental Chemistry and Technology

Attention to the environment and its problems has undergone unprecedented growth in recent years [...]

The Microplastic Cycle: An Introduction to a Complex Issue

The microplastic cycle was originally and formally introduced and defined as a novel concept and paradigm for understanding plastic pollution and its fluxes across ecosystem reservoirs. This concept has now been expanded to include macroplastic particles and links all aspects of the fate, transport, and effects of plastic pollution, including source-receptor models in the environment, and expanded on previously established perspectives that viewed the plastic pollution issue in a less integrated manner. The value of this paradigm is that this perspective integrates three basic scientific spheres: environmental chemistry, biology (i.e., trophic transfer), and human health. The goal of this chapter is to introduce readers to the microplastic pollution problem and to outline the microplastic cycle as a concept and holistic paradigm for addressing this ubiquitous environmental and potential public health problem. The specific objectives of this chapter were to (1) introduce this volume and its chapters by outlining the microplastic pollution issue in the context of the entire plastic cycle; (2) evaluate fluxes of microplastics across different ecosystem compartments, including the atmosphere, lithosphere, hydrosphere. and biosphere, including humans; and (3) provide insights on public policy and potential solutions to the microplastic pollution problem.

Uso de Livro-Texto Como Suporte nas Disciplinas de Cursos Universitários

ResumoEmbora haja livros didáticos nas bibliotecas como material de apoio para as disciplinas, tem-se a necessidade de mostrar aos estudantes as especificidades da região na qual vivem, visto que muitos desses livros são exógenos. Diante do exposto, o livro-texto Química Ambiental: uma abordagem introdutória e generalista, foi uma tentativa de encontrar um material didático que além de incluir assuntos da disciplina, apresentasse exemplos locais. Foram entrevistados estudantes, que revelaram que a utilização do livro-texto, além de uma ferramenta de apoio no decorrer da disciplina, também desempenhou um importante papel no processo de sua formação profissional e como cidadãos conscientes e atuantes no espaço geográfico em que vivem. Palavras-chave: Material de Apoio. Percepção. Estudantes. AbstractAlthough there are schoolbooks in the libraries as support material for the subjects, there is a need to show students the specifics of the region where they live, since many of these schoolbooks are exogenous. Given the above, the textbook Environmental Chemistry: an introductory and generalist approach, was an attempt to find didactic material that in addition to including subjects of the discipline, presented local examples. Students were interviewed and revealed that the use of this textbook, in addition to being a support tool throughout the course, also played an important role in the process of their professional training and as conscious and active citizens in the geographical space in which they live. Keywords: Support Material. Perception. Students.