structure

Auxin-like and Cytokinin-like Effects of New Synthetic Pyrimidine Derivatives on the Growth and Photosynthesis of Wheat

Published on: 19th March, 2024

The regulatory effect of new synthetic thienopyrimidine derivatives on the growth and photosynthesis of wheat (Triticum aestivum L.) variety Svitlana in the vegetative phase was studied. The regulatory effect of new synthetic thienopyrimidine derivatives was compared with the regulatory effect of auxin IAA (1H-indol-3-yl)acetic acid) or synthetic plant growth regulators Methyur (sodium salt of 6-methyl-2-mercapto-4-hydroxypyrimidine) and Kamethur (potassium salt of 6-methyl-2-mercapto-4-hydroxypyrimidine). After 2 weeks, morphometric parameters (such as average length of shoots and roots (mm), average biomass of 10 plants (g)) and biochemical parameters (such as content of photosynthetic pigments (µg/ml)) of wheat plants grown from seeds treated with synthetic thienopyrimidine derivatives, or auxin IAA, or synthetic plant growth regulators Methyur and Kamethur at a concentration of 10-6M, were measured and compared with similar parameters of control wheat plants grown from seeds treated with distilled water. The regulatory effect of new synthetic thienopyrimidine derivatives on the morphometric and biochemical parameters of wheat plants was similar or higher compared to the regulatory effect of auxin IAA, or synthetic plant growth regulators Methyur and Kamethur. The relationship between the chemical structure of new synthetic thienopyrimidine derivatives and their regulatory effect on the growth and photosynthesis of wheat plants was revealed. The most biologically active thienopyrimidine derivatives are proposed to be used as new synthetic physiological analogues of auxins and cytokinins to improve growth and increase photosynthesis of wheat (Triticum aestivum L.)variety Svitlana in the vegetative phase.
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Endoscopic Endonasal total Removal of a Suprasellar, Preinfundibular Retro Chiasmatic Craniopharyngioma: A Surgical Case Report

Published on: 26th March, 2024

Craniopharyngiomas are benign tumors (WHO Grade I), seen in children and adults. Because of their location, they can require challenging clinical and surgical management. In fact, often, because of the presence of calcifications, of a capsule very strongly adherent to neurovascular structures, of the relationship with hypophysis, pituitary stalk, chiasm, carotids, the circle of Willis, basilar artery, and third ventricle, risk of mortality and morbidity is still mandatory. Various surgical techniques have been proposed: transcranial, transsphenoidal, and supraorbital approaches for surgical resection and treatment of craniopharyngiomas. Still, there is no common consent, but often the endonasal transsphenoidal extended procedures are considered the gold standard in many cases. We present a surgical technique of a case of complete surgical removal of an infundibular and retro chiasmatic craniopharyngioma, via an endoscopic endonasal transphenoidal transplanum approach.
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Sites and Zones of Maximum Reactivity of the most Stable Structure of the Receptor-binding Domain of Wild-type SARS-CoV-2 Spike Protein: A Quantum Density Functional Theory Study

Published on: 12th April, 2024

Today, it is well known that Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has four types of proteins within its structure, between them the spike protein (S). The infection mechanism is carried out by the entry of the virus into the human host cell through the S protein, which strongly interacts with the human cell receptor angiotensin-converting enzyme 2 (ACE2). In this work, we propose an atomic model of the Receptor Binding Domain (RBD) of the S spike protein of the wild-type SARS-CoV-2 virus. The molecular structure of the model was composed of 50 amino acids that were chemically bonded, starting with Leucine and ending with one amino acid Tyrosine. The novelty of our work lies in the importance of knowing the sites and zones of maximum reactivity of the RBD from the fundamental levels of quantum mechanics considering the atomic structure of matter. For this, the local and global reactivity indices of the RBD were calculated, such as frontier orbitals, Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO), Fukui indices, chemical potential, chemical hardness, electrophilicity index; with this, it will be possible to know what type of molecules are more likely to interact with the RBD structure, and in this way, new knowledge will be generated at the quantum, atomic and molecular level to inhibit the virulent effects of wild-type SARS-CoV-2. Finally, in order to identify the functional groups within the most stable structure and thereby verify the future reactions that can be carried out between the RBD structure and biomolecules, the Infrared (IR) absorption spectrum was calculated. For this work, we used Material Studio v6.0 which uses the density functional theory (DFT) implemented in its DMol3 computational code. The IR spectrum was obtained using the Spartan ‘94 computer code. One novelty would be that we found nine amino acids more that could make the RBD and ACE2 binding further the already known. Thus, the Mulliken charge distribution indicates that the highest concentrations of positive and negative charge are found in the zones 477S, 478T, 484E, and 501N amino acids letting ionic or Van der Waals possible interactions with other structures.
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Exploring the Barriers to Clinic-based Screening for Sexually Transmitted Infections (STIs) among Men in Ghana: A Qualitative Study

Published on: 16th April, 2024

The burden of sexually transmitted infections (STIs) continues to increase with over one million curable STIs occurring daily worldwide. Sex disparity in the rates of testing for STIs can compromise the efforts to reduce the incidence of STIs. The study aimed to explore the barriers to facility-based screening for STIs among men in Ghana. A qualitative exploratory design was employed in this study. Using a semi-structured interview guide, individual in-depth interviews were conducted among purposively sampled men from November 2019 to January 2020. Data saturation was achieved at the ninth participant. Audio-recorded interviews were transcribed verbatim and analysed thematically through Braun and Clarke’s approach. Four themes emerged from the analyses: (1) lack of privacy from healthcare providers, (2) mistrust of healthcare providers, (3) the burden of handling thoughts of positive status, and (4) fear of stigmatisation. These barriers deterred men from seeking clinic-based screening for STIs. The barriers were multi-factorial and a major hindrance to ensuring that people are aware of their STI status through screening and diagnosis. It is imperative to consider these barriers when designing STI screening interventions and policies to help promote facility-based screening for STIs among men in Ghana.
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A Critical Review on Some Recent Developments in Comparison of Biological Sequences

Published on: 25th April, 2024

The present review highlights some of the very important contributions to non-alignment ways of comparing biological sequences, which may be genome sequences of nucleotides, protein sequences of amino acids, or sequences of protein secondary structures. The discussion centers around specific methods applicable to the comparison of three types of sequences. The methods of comparison of genome sequences are based on three pairs of biological groups of nucleotides; the same for protein sequences are based on either physio-chemical property values of amino acids or on classified groups of amino acids of different cardinalities obtained from the physio-chemical properties; the same for sequences of secondary structures of proteins are based on their sequential expressions of structure elements of cardinality three and four. Comparison is made in the time domain and also in the frequency domain. Different taxa of known phylogeny are considered for comparison. It tries to find out the specific method of comparison, which can show the exact phylogeny of the taxa. If a new sequence appears in the database, it becomes essential to know its phylogeny. For this purpose, a phylogenetic tree is drawn on the sequences of the known taxa together with this new sequence using the best possible method. If the species having this new sequence belongs to the old taxa, there is nothing to worry about. Otherwise, the species with the new sequence has to be studied separately. This is the general reason for the construction of a phylogenetic tree in any form of biological sequence comparison.
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Electronic and Thermo-Dynamical Properties of Rare Earth RE2X3 (X=O, S) Compounds: A Chemical Bond Theory

Published on: 24th April, 2024

The electrical, mechanical, and thermodynamic properties of cubic structured rare earth sesqui-chalcogenides RE2X3 (RE = La-Lu, X = O, S) are examined in this work using the chemical bond theory of solids. For these materials, the values of the homopolar gaps (Eh), ionic gaps (Ec), and average energy gaps (Ep) have been assessed. It has been discovered that the calculated values of the homopolar gap (Eh) and average energy gap (Ep) are in great agreement with the values derived from the Penn and Phillips models. The electrical, mechanical, and thermodynamic properties of these materials (RE2O3), such as their bulk modulus and heat of formation, have been estimated using the bond ionicity values. The computed values accord very well with the theoretical results that have been published thus far.PACS No.: 71.20.Eh, 71.15.Mb, 61.50.Ks, 71.15.Mb
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