Chemistry Research Articles

Role of Click Chemistry in development of Biomedicines

Role of Click Chemistry in development of Biomedicines

Advanced fuels from ethanol – a superstructure optimization approach

Advanced fuel design through integration of chemistries leading to different components: alcohols (blue); ethers (green); and olefins, parafins, and aromatics (yellow).

Teaching Chemistry in Attractive Ways

Teaching Chemistry in Attractive Ways

Una propuesta de secuencia basada en el contexto, para la promoción de la argumentación científica en el aprendizaje de las reacciones químicas con estudiantes de educación técnico profesional

espanolEl proposito de este estudio fue analizar las limitaciones, posibilidades y condicionantes de una secuencia cuyo foco es la contextualizacion de los contenidos, abordando problemas reales y cercanos, permitiendo al estudiante poner en practica la teoria en situaciones autenticas, promoviendo el pensamiento critico y la argumentacion cientifica, en estudiantes de Educacion Media Tecnico Profesional. Se trabajo con una muestra de 50 estudiantes (14-17 anos) de un establecimiento educacional que imparte las carreras de Quimico Industrial y Explotacion Minera. La recoleccion de datos proviene de las actividades desarrolladas por los estudiantes respecto al el contenido de reacciones quimicas bajo el contexto minero, para promover el desarrollo en la argumentacion cientifica. Los resultados muestran que un alto porcentaje de los estudiantes, logran seleccionar una conclusion en base a pruebas y utilizar informacion de caracter disciplinar, socio-politico, etico y ambiental al momento de elaborar una argumentacion cientifica en un juego de roles EnglishThis work analyzes the limitations, possibilities and conditioning factors of a sequence whose focus is the contextualization of the contents, addressing real and close problems, allowing the student to put the theory into practice in authentic situations, promoting critical thinking and argumentation scientific, in students of Middle School Professional Technical. We worked with a sample of 50 students (14-17 years old) who study Industrial Chemistry and Mining. Data collection comes from the activities in which students participated in the content of chemical reactions under the mining context, to promote development in scientific argumentation. The results show that a high percentage of the students manage to select a conclusion based on tests and use the information of a disciplinary, socio-political, ethical, and environmental nature when preparing a scientific argument in a role play

The Fascinating Chemistry of Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates and Related Compounds

The Fascinating Chemistry of Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates and Related Compounds

Layer-by-layer assembled magnetic molecularly imprinted nanoparticles for the highly specific recovery of luteolin from honeysuckle leaves

Eco-friendly layer-by-layer assembled magnetic molecularly imprinted nanomaterials were designed for the specific recovery of luteolin from bio-waste honeysuckle leaves.

First Zagreb index on a fuzzy graph and its application

The Zagreb index (ZI) is a very important graph parameter and it is extensively used in molecular chemistry, spectral graph theory, network theory and several fields of mathematics and chemistry. In this article, the first ZI is studied for several fuzzy graphs like path, cycle, star, fuzzy subgraph, etc. and presented an ample number of results. Also, it is established that the complete fuzzy graph has maximal first ZI among n-vertex fuzzy graphs. Some bounds of first ZI are discussed for Cartesian product, composition, union and join of two fuzzy graphs. An algorithm has been designed to calculate the first ZI of a fuzzy graph. At the end of the article, a multi-criteria decision making (MCDM) method is provided using the first ZI of a fuzzy graph to find the best employee in a company. Also a comparison is provided among related indices on the result of application and shown that our method gives better results.

Graph neural network: Current state of Art, challenges and applications

Several areas in science and engineering have the relationships between their underlying data which can be represented as graphs, for example, molecular chemistry, node prediction, link prediction, computer vision, pattern recognition, social networking and more. In this article, an approach to a model which can handle such type of data is elaborated, which is Graph Neural Networks (GNN). GNN encompasses the neural network technique to process the data which is represented as graphs. Due to its massive success, GNN has made its way into many applications and is a popular architecture to work upon. This paper explains the graph neural networks, its area of applications and its day-to-day use in our daily lives. Some of the very common application is a social networking site which is on our hands regularly, and another could be the recommendation system which recommends us friends, or the products of our interest based on our pat choices and preferences. This paper also demonstrates the basic challenges encountered while implementing GNN. This paper will be a great help to those researchers who are keen to work in the domain of GNN.

Interaction of hydrogen peroxide molecules with non-specific DNA recognition sites

Ion beam therapy is one of the most progressive methods in cancer treatment. Studies of the water radiolysis process show that the most long-living species that occur in the medium of a biological cell under the action of ionizing irradiation are hydrogen peroxide (H$_2$O$_2$) molecules. But the role of H$_2$O$_2$ molecules in the DNA deactivation of cancer cells in ion beam therapy has not been determined yet. In the present paper, the competitive interaction of hydrogen peroxide and water molecules with atomic groups of non-specific DNA recognition sites (phosphate groups PO$_4$) is investigated. The interaction energies and optimized spatial configurations of the considered molecular complexes are calculated with the help of molecular mechanics method and quantum chemistry approach. The results show that the H$_2$O$_2$ molecule can form a complex with the PO$_4$ group (with and without a sodium counterion) that is more energetically stable than the same complex with the water molecule. Formation of such complexes can block genetic information transfer processes in cancer cells and can be an important factor during ion beam therapy treatment.

Teaching Geometries of Coordination Compounds Using Computational Chemistry: Examples of Two Kinds of Four-coordinate Complexes

In this article, two examples have been designed to be used for teaching geometries of coordination compounds by using computational chemistry, including molecular dynamics and quantum chemistry calculations. Specifically, we describe three kinds of software packages, molclus, GFN2-xTB and ORCA, and show how they can be used to predict the geometries of [Zn(NH3)4]2+ and [Cu(NH3)4]2+. All assignments are aimed at helping students gain practice with computational chemistry software while at the same time understanding the differences between tetrahedral and square planar configurations.

On the role of water in the hydrogen bond network in DESs: an ab initio molecular dynamics and quantum mechanical study on the urea-betaine system.

We herein report an ab initio molecular dynamics study on a natural DES composed of urea and betaine in a 3 : 2 ratio, as a test case for evaluating the water effect. The article deals with a theoretical study using both ab initio molecular dynamics and quantum chemistry computations in order to unravel the role of water in the nanostructure of a urea-betaine mixture. Preliminary molecular dynamics outcomes (both radial and spatial distribution functions) suggest that water promotes the association between urea and betaine by increasing the hydrogen bond network and precluding the aggregation of urea molecules. In other words, the presence of water allows a less restrictive hydrogen bond network, presenting a regimen where the strong hydrogen bond interactions are replaced by a wide variety of weaker hydrogen bond interactions. On the other hand, in a water free DES there is a regimen where strong urea-betaine interactions are dominant. It is shown that second order perturbation theory energy analysis provides cogent insights into charge spreading and hydrogen bond patterns. A vibrational analysis (both IR and power spectrum) over the ab initio molecular dynamics trajectories in the water free DES as well as in the urea-betaine-water systems reveals that our results are consistent with the second order perturbation theory analysis and with the hydrogen bond network pattern.

Развитие идей А.Н. Теренина в Томском университете: этапы и персоналии

The paper presents the stages of development of photonics of molecules at Tomsk State University. Student of Academician A.N. Terenina - N.A. Since 1935 Prilezhaeva stood at the origins of the birth and development of domestic photochemistry, laid the foundation for the Tomsk school of spectroscopists, the only one beyond the Urals at that time. Research in the field of molecular spectroscopy and quantum chemistry of complex molecules began in 1950 by a student of N.A. Prilezhaeva - V.I. Danilova, later a professor at TSU. Fundamental questions related to the establishment of a relationship between the spectra, the structure of the electron shell and the physicochemical properties of a number of classes of complex organic molecules were posed and resolved. The generalizations made were of great importance for the theory of molecular spectra and practical application and allowed V.I. Danilova in the 1970-80s. create your own scientific school.

Yebes 40 m radio telescope and the broad band NANOCOSMOS receivers at 7 mm and 3 mm for line surveys.

Yebes 40m radio telescope is the main and largest observing instrument at Yebes Observatory and it is devoted to Very Long Baseline Interferometry (VLBI) and single dish observations since 2010. It has been covering frequency bands between 2 GHz and 90 GHz in discontinuous and narrow windows in most of the cases, to match the current needs of the European VLBI Network (EVN) and the Global Millimeter VLBI Array (GMVA). Nanocosmos project, a European Union funded synergy grant, opened the possibility to increase the instantaneous frequency coverage to observe many molecular transitions with single tunnings in single dish mode. This reduces the observing time and maximises the output from the telescope. We present the technical specifications of the recently installed 31.5 - 50GHz (Q band) and 72 - 90.5 GHz (W band) receivers along with the main characteristics of the telescope at these frequency ranges. We have observed IRC+10216, CRL 2688 and CRL 618, which harbour a rich molecular chemistry, to demonstrate the capabilities of the new instrumentation for spectral observations in single dish mode. The results show the high sensitivity of the telescope in the Q band. The spectrum of IRC+10126 offers a signal to noise ratio never seen before for this source in this band. On the other hand, the spectrum normalised by the continuum flux towards CRL 618 in the W band demonstrates that the 40 m radio telescope produces comparable results to those from the IRAM 30 m radio telescope, although with a smaller sensitivity. The new receivers fulfil one of the main goals of Nanocosmos and open the possibility to study the spectrum of different astrophysical media with unprecedented sensitivity.

Designing light-driven rotary molecular motors.

The ability to induce and amplify motion at the molecular scale has seen tremendous progress ranging from simple molecular rotors to responsive materials. In the two decades since the discovery of light-driven rotary molecular motors, the development of these molecules has been extensive; moving from the realm of molecular chemistry to integration into dynamic molecular systems. They have been identified as actuators holding great potential to precisely control the dynamics of nanoscale devices, but integrating molecular motors effectively into evermore complex artificial molecular machinery is not trivial. Maximising efficiency without compromising function requires conscious and judicious selection of the structures used. In this perspective, we focus on the key aspects of motor design and discuss how to manipulate these properties without impeding motor integrity. Herein, we describe these principles in the context of molecular rotary motors featuring a central double bond axle and emphasise the strengths and weaknesses of each design, providing a comprehensive evaluation of all artificial light-driven rotary motor scaffolds currently present in the literature. Based on this discussion, we will explore the trajectory of research into the field of molecular motors in the coming years, including challenges to be addressed, potential applications, and future prospects.

AS CONTRIBUIÇÕES DAS ATIVIDADES EXPERIMENTAIS NO ENSINO DE QUÍMICA

O ensino de Química tem mantidos práticas que estão relacionadas às abordagens mais tradicionais, baseadas em aulas expositivas, descontextualizadas, retirando, assim, da química a sua natureza que é, essencialmente, experimental. A consequência disso é a formação de estudantes que não despertam o interesse para essa área de conhecimento. Inquieta-nos saber: quais as principais características das práticas experimentais no ensino de Química? Para responder a essa inquietação, essa pesquisa teve o objetivo de identificar as principais abordagens experimentais no ensino de Química. O campo de pesquisa foram duas escolas da Rede Pública do Estado de Pernambuco e os participantes da pesquisa foram 32 estudantes do Ensino Médio dessas escolas. Foram realizados questionários com os estudantes com pergunta aberta e fechadas, e entrevistas com 2 professores. Foi observado que as práticas experimentais no Ensino de química, na escola de rede pública, nem sempre prioriza as aulas práticas, muitas vezes por conta do espaço e também dos materiais. O objetivo das práticas experimentais é auxiliar os estudantes no processo de ensino-aprendizagem, e também ajudar os estudantes na aprendizagem dos conteúdos de química, de acordo com as respostas dos estudantes, observamos que eles acham muito importante essa prática, e 44,15% dos alunos responderam que o professor não realiza essa prática, a utilização das práticas experimentais é muito importante para a aprendizagem dos alunos, mais nem sempre o espaço favorece. Observamos também, através de uma pesquisa bibliográfica, que existem diversas possibilidades do professor realizar essas atividades experimentais em sala de aula. Além disso, verificamos também o quanto o ensino de Química precisa ser renovado, afinal, esses estudos trazem perspectivas que não são corriqueiras nas salas de aula. Muitos professores permanecem com práticas experimentais relacionadas às abordagens tradicionais. Assim, ressaltamos a importâncias dessas propostas serem discutidas nos cursos de formação de professores para que o ensino, no nosso caso, da Química supere as práticas tradicionais que, historicamente são realizadas.

PENGEMBANGAN BAHAN AJAR KIMIA DASAR BERBASIS CONCEPTUAL CHANGE TEXT PADA MATERI REDOKS

DEVELOPMENT OF TEACHING MATERIALS BASED ON CONCEPTUAL CHANGE TEXT ON REDOX MATERIALS FOR BASIC CHEMICALS ON REDOX CONCEPTAbstractThe problem in this study is that there are still many students who have difficulty learning basic chemical concepts and experience misconceptions. One way to overcome student difficulties in understanding the concept of chemistry is to provide quality learning media. This study aims to produce learning media in the form of quality teaching materials. The teaching materials developed are chemical teaching materials based on Conceptual Change Text (CCT). The research data were obtained from the results of validation of teaching materials from experts and the results of a questionnaire distributed to 30 students. This research was conducted using the R&D method with the research subjects being teaching materials and students. Based on the data generated in this study, it was found that the development of CCT-based teaching materials when viewed from the aspects of content feasibility, presentation feasibility, language assessment, multiple chemical representations assessed by some experts, it can be concluded that the teaching materials developed are good and suitable for use in the field with some improvements with an average validation value of 4. Besides, a limited test was also carried out on students of the teaching materials that were being developed and students responded well to the teaching materials because it could help them understand the average value of 85. AbstrakPermasalahan dalam penelitian ini adalah masih banyaknya mahasiswa yang mengalami kesulitan dalam belajar konsep kimia dasar dan mengalami miskonsepsi. Salah satu cara untuk mengatasi kesulitan mahasiswa dalam memahami konsep kimia adalah menyediakan media pembelajaran yang berkualitas. Penelitian ini bertujuan untuk menghasilkan media pembelajaran berupa bahan ajar yang berkualitas. Bahan ajar dikembangkan adalah bahan ajar kimia berbasis Conceptual Change Text (CCT). Data penelitian diperoleh dari hasil validasi bahan ajar dari para ahli dan hasil angket yang disebarkan kepada 30 orang mahasiswa. Penelitian ini dilakukan dengan metode R&D dengan subjek penelitian adalah bahan ajar dan mahasiswa. Berdasarkan data yang dihasilkan dalam penelitian ini diperoleh hasil bahwa pengembangan bahan ajar berbasis CCT jika dilihat dari aspek kelayakan isi, kelayakan penyajian, penilaian bahasa, penilaian multiple representasi kimia yang dinilai oleh beberapa ahli dapat disimpulkan bahwa bahan ajar yang dikembangkan sudah baik dan layak digunakan di lapangan dengan beberapa perbaikan dengan rata-rata nilai validasi 4. Selain itu juga dilakukan uji terbatas terhadap mahasiswa terhadap bahan ajar yang sedang dikembangkan dan mahasiswa merespon dengan baik bahan ajar tersebut karena bisa membantu mereka dalam memahami dengan rata-rata nilai 85. konsep.

Plantas medicinais como alternativa para o estudo de taxonomia e funções orgânicas no Ensino Médio

O uso de plantas medicinais fazem parte do cotidiano dos alunos e suas famílias, que as utilizam levando em conta o conhecimento popular sobre seu poder de cura. Neste contexto a construção de um horto-medicinal possibilita a visualização e contextualização prática de alguns conteúdos na Área de Ciências da Natureza, em especial a Biologia e a Química. Este trabalho objetivou-se, identificar e coletar as plantas medicinais de uso popular entre as famílias dos estudantes em uma Escola Estadual no Município de Pinheiros/ES, para servir de aporte teórico – metodológico no ensino de taxonomia e funções orgânicas, presentes nos princípios ativos contidos nas plantas, além de conhecer as propriedades terapêuticas para conscientizar os alunos sobre propriedades medicinais e o perigo do seu uso abusivo ao organismo, além de reproduzir as espécies mais utilizadas pelas famílias da comunidade. Buscou-se ainda, utilizar a proposta para promover a integração das áreas e elevar os resultados nas disciplinas. Para efetivação do projeto, foi realizada a pesquisa de campo, por meio de entrevistas, e coletas das plantas medicinais pelos estudantes do 3º ano do Ensino Médio. As plantas coletadas foram, identificadas e classificadas, reproduzidas em um horto-medicinal, construído com materiais reaproveitados encontrados na escola, permitindo trabalhar de forma interdisciplinar na construção e embelezamento estético, através de canteiros suspensos, para otimização de espaços. A construção do horto medicinal contribuiu para os estudos de taxonomia e das funções orgânicas, além de potencializar aprendizagem significativa e contextualizada através do conhecimento e uso de espécies medicinais.

Integración de la Docencia y la Extensión en el aula de Química

Reconociendo la importancia de los aportes de la Extensión a la formación de profesionales comprometidos con su rol social y de su potencial para otorgar significatividad a los contenidos disciplinares del currículum de las carreras de grado, trayendo un contexto social que les dé sentido y habilite su representación, el presente artículo aborda reflexiones acerca de la necesidad de construir nuevos lazos entre los aportes y propuestas de la Extensión desarrollada en la Facultad de Ciencias Exactas y las propuestas de enseñanza. En este marco, se da cuenta de los posicionamientos docentes que sustentaron el diseño de una serie de trabajos prácticos de laboratorio de la asignatura Introducción a la Química. Estos trabajos de laboratorio pretenden motivar el aprendizaje de la Química a través de la búsqueda de posibles soluciones a problemas concretos de la comunidad inmediata, fomentando una actitud proactiva de las/os estudiantes en la elaboración de nuevos saberes en y a través de la práctica. La construcción metodológica puso el eje en propiciar situaciones que promuevan aprendizajes significativos trayendo la Extensión al aula universitaria.

How Scientific is Chemistry?

Abstractφ for philosophy, χ for chemistry. Is there a connection? Is there any interaction? Do chemists have something useful to learn from philosophers? Do philosophers from chemists? How can we define if chemistry is a science, or at least trustworthy? Which disciplines, styles and personalities are progressive in chemistry? Which ones are truth‐seekers, progress‐seekers or profit‐seekers? Is there a point in asking these questions? Is there even an answer to them?

In conversation with Nigel Scrutton.

Nigel Scrutton FRS is Professor of Molecular Enzymology and Biophysical Chemistry at the University of Manchester and former Director of the Manchester Institute of Biotechnology (MIB). He obtained a first degree in Biochemistry from King's College London and followed this with a PhD at the University of Cambridge. His doctoral research, undertaken in Richard Perham's laboratory, yielded fundamental breakthroughs in enzyme redesign that have stood the test of time. Nigel was awarded a ScD degree by the University of Cambridge in 2003. After faculty positions at the University of Leicester, Nigel was appointed Professor at the University of Manchester in 2005. Over the last 15years, he has cemented his reputation as a world leader in the fields of enzyme engineering and biocatalysis, synthetic biology, biophysics and biomanufacturing, notably by establishing and directing the Synthetic Biology Research Centre 'SYNBIOCHEM' and UK Future Biomanufacturing Research Hub. In recognition of his scientific contributions, he has received many academic awards and accolades, including being elected as Fellow of the Royal Society earlier this year. In this interview, he highlights how fundamental studies of enzymatic catalysis and mechanisms are driving key advances in biotechnology and biomanufacturing, and describes how the experiences and mentors of his formative years helped to shape his successful career at the interface between discovery and application-focused science.