Structural Units Research Articles

Synthesis, crystal structure and Hirshfeld surface analysis of 5,5-diphenyl-2-[2-(propan-2-ylidene)hydrazin-1-yl]-4,5-dihydro-1H-imidazol-4-one N,N-dimethylformamide hemisolvate

The asymmetric unit of the title structure, 2C18H18N4O2·C3H7NO, consists of two independent molecules of the substituted imidazolone having different conformations, and one molecule of solvent DMF. The two imidazolone molecules are linked by N—H...N and C—H...O hydrogen bonds and the DMF is joined to one of these by an N—H...O hydrogen bond. Additional N—H...N and C—H...O hydrogen bonds link these groups into corrugated layers parallel to the (101) plane with the layers joined by C—H...π (ring) interactions. A Hirshfeld surface analysis indicated that H...H interactions account for over half of the intermolecular contacts.

An Analaysis of Category Shift and Its Equivalence in Tourism Promotion Video Subtitles

This study aims to identify the types of category shift defined by Catford theory (1965) and Nida’s for translation equivalence (1964). The descriptive qualitative method was used to analyze the data. This study used a secondary source from four videos. First, Badung Heaven of Dream, second, Pantai Melasti were posted in Jegeg Bagus Badung YouTube Channel. Third, Pungin puspa, and fourth, A Story of Sacred Bond from West Bali were posted on Jegeg Bagus Bali YouTube Channel. This study analyzed words, phrases, clauses, terms, and sentences. Total data were 33 data, which analyzed qualitatively. The analysis showed that there were four types of category shift. They were Structure shift (17), Class shift (1), Unit shift (10), and Intra-system shift (5). This study also found two types of translation equivalence. Namely Formal equivalence (21) and dynamic equivalence (12). The most dominant types of category shift that found is structure shift and the most dominant equivalence that found is formal equivalence.

Evaluation of Spatial Structure and Homogeneity of Bamboo and Broad-Leaved Mixed Forest

Evaluation of Spatial Structure and Homogeneity of Bamboo and Broad-Leaved Mixed Forest

A pseudo-cubic metal-organic cage with conformationally switchable faces for dynamically adaptive guest encapsulation.

The creation of hosts capable of accommodating different guest molecules may enable these hosts to play useful roles in chemical purifications, among other applications. Metal-organic cages are excellent hosts for various guests, but they generally incorporate rigid structural units that hinder dynamic adaptation to specific guests. Here we report a conformationally adaptable pseudo-cubic cage that can dynamically increase its cavity volume to fit guests with differing sizes. This pseudo-cube incorporates a tetramine subcomponent with 2,6-naphthalene arms that cooperatively adopt a non-planar conformation, enabling the cage faces to switch between endo and exo states. A wide range of guest molecules were observed to bind within the cavity of this cage, spanning a range of sizes from 46% to 154% of the cavity volume of the empty cage. Experimental and computational evidence characterizes the flipping of cage faces from endo to exo, expanding the cavity upon binding of larger guests.

Nucleosome wrapping states encode principles of 3D genome organization

Nucleosome is the basic structural unit of the genome. During processes like DNA replication and gene transcription, the conformation of nucleosomes undergoes dynamic changes, including DNA unwrapping and rewrapping, as well as histone disassembly and assembly. However, the wrapping characteristics of nucleosomes across the entire genome, including region-specificity and their correlation with higher-order chromatin organization, remains to be studied. In this study, we investigate the wrapping length of DNA on nucleosomes across the whole genome using wrapping-seq. We discover that the chromatin of mouse ES cells forms Nucleosome Wrapping Domains (NRDs), which can also be observed in yeast and fly genomes. We find that the degree of nucleosome wrapping decreases after DNA replication and is promoted by transcription. Furthermore, we observe that nucleosome wrapping domains delineate Hi-C compartments and replication timing domains. In conclusion, we have unveiled a previously unrecognized domainization principle of the chromatin, encoded by nucleosome wrapping states.

Dynamic Mechanical Properties and Energy Absorption Capabilities of Polyureas Through Experiments and Molecular Dynamic Simulation.

Polyurea (PUR) has been widely used as a protective coating in recent years. In order to complete the understanding of the relationship between PUR microstructure and its energy absorption capabilities, the mechanical and dynamic performance of PURs containing various macrodiol structural units were compared using material characterization techniques and molecular dynamic simulation. The results showed that the PUR polycarbonate diols formed as energy absorbing materials showed high tensile strength, high toughness, and excellent loss factor distribution based on the comparison of stress-strain tensile curves, glass transition temperatures, phase images, and dynamic storage loss modulus. External energy from simple shear deformation was absorbed to convert non-bond energy, in particular, based on fractional free volume, interaction energy, and total energy and hydrogen bond number change from the molecular dynamic simulation. Hydrogen bonds formed between soft segments and hard segments in the PURs have been proven to play a significant role in determining their mechanical and dynamic performance. The mechanical and dynamic properties of PURs characterized and tested using experimental techniques were quantified effectively using molecular dynamic simulation. This is believed to be an innovative theoretical guidance for the structural design of PURs at the molecular level for the optimization of energy absorption capabilities.

Recent advances in the oxidative activation of the C2-C3 π bond of indoles and its applications.

The oxidative C2-C3 π bond activation strategy is the most efficient tool to synthesize oxygen-containing indoline, which frequently appears in natural products with various biological activities as structural units. Recently, the oxidation-induced cascade strategy through oxygenation activation of the indolic C2-C3 π bond of indoles has received much attention for its use in efficiently establishing complex indoline with oxygen-containing molecular architectures, and holds tremendous potential in the total synthesis of indole alkaloids. It can be carried out using potential activated indole radical cations or imine cation intermediates produced via oxidative C2-C3 π bond activation of indole with various nucleophiles or ring-forming reagents by employing simple and non-decorated indoles as starting substrates. Herein, we have reviewed recent advances in the oxidation-induced cascade strategies connecting intra-cyclization or inter-annulation reactions, nucleophilic or radical additions and rearrangement via the oxidative C2-C3 π bond activation of indoles over the past two decades, providing diverse oxygen-containing indolines such as indoxyls, indoline oxygen-heterocycles and indolones. The features and mechanisms of different types of oxidation-induced cascade reactions have been summarized and represented, and examples have been given of their asymmetric reactions and applications in the total synthesis of indole alkaloids.

Synergistic Enhancement of Radar Wave Absorption in SiC/Al2O3 Composites via Structural Tuning, Composition Optimization, and Unit Design

Synergistic Enhancement of Radar Wave Absorption in SiC/Al2O3 Composites via Structural Tuning, Composition Optimization, and Unit Design

Flexibility index: a general descriptor of polarization ability in crystalline materials

Although optical phenomena in crystalline materials are different, they are all generated from polarization processes of microscopic structural units under photoelectric field. To develop the simple and effective model that...

Short-range order and hidden energy scale in geometrically frustrated magnets

In geometrically frustrated (GF) magnets, conventional long-range order is suppressed due to the presence of primitive triangular structural units, and the nature of the ensuing ground state remains elusive.

4-Amino-1,2,3-triazine 2-oxide: a promising structural unit for the design and synthesis of novel energetic materials with good thermal stability and low impact sensitivity

Two new [6,6]-fused ring energetic molecules were designed and synthesised using 4-amino-1,2,3-triazine 2-oxide as the basic skeleton unit.

Antimonotungstate-Based Heterometallic Framework Formed by the Synergistic Strategy of In Situ-Generated Krebs-Type Building Units and the Substitution Reaction and Its High-Efficiency Biosensing KRAS Gene.

A novel antimonotungstate (AT)-based heterometallic framework {[Er(H2O)6]2[Fe4(H2pdc)4(B-β-SbW9O33)2]}·50H2O (1, H2pdc = pyridine-2,5-dicarboxylic acid) was obtained through a synergistic strategy of in situ-generated transition-metal-encapsulated polyoxometalate (POM) building units and the substitution reaction. Its structural unit is composed of a tetra-FeIII-substituted Krebs-type [Fe4(H2pdc)4(B-β-SbW9O33)2]6- subunit and two [Er(H2O)6]3+ cations. This subunit can be regarded as a product of carboxylic oxygen atoms of H2pdc ligands replacing active water ligands in the [Fe4(H2O)10(B-β-SbW9O33)2]6- species. Apparently, the substitution action of carboxylic oxygen atoms of H2pdc ligands for active water ligands, together with the coordination function of Er3+ ions, plays a connection role in the architecture of the three-dimensional (3-D) heterometallic framework. Based on the stability and high redox activity of 1, a glassy carbon electrode modified by 1 is used for the construction of an electrochemical biosensor (ECBS). Thus, such 1-based ECBS can sensitively detect the KRAS gene (a key genetic marker for identifying the occurrence of malignant tumors) and displays a low detection limit (0.106 pM), high selectivity, and reproducibility. This work not only provides a feasible approach to prepare novel multicomponent POM-based heterometallic frameworks but also establishes a new platform for biosensing the KRAS gene and extends the application scope of POM-based functional materials.

Nanoscale Characterization of Interaction of Nucleosomes with H1 Linker Histone.

In eukaryotic nuclei, DNA is wrapped around an octamer of core histones to form nucleosomes. H1 binds to the linker DNA of nucleosome to form the chromatosome, the next structural unit of chromatin. Structural features on individual chromatosomes contribute to chromatin structure, but not fully characterized. In addition to canonical nucleosomes composed of two copies each of histones H2A, H2B, H3, and H4 (H3 nucleosomes), centromeres chromatin contain nucleosomes in which H3 is replaced with its analog CENP-A, changing structural properties of CENP-A nucleosomes. Nothing is known about the interaction of H1 with CENP-A nucleosomes. Here we filled this gap and characterized the interaction of H1 histone with both types of nucleosomes. H1 does bind both types of the nucleosomes forming more compact chromosome particles with elevated affinity to H3 nucleosomes. H1 binding significantly increases the stability of chromatosomes preventing their spontaneous dissociation. In addition to binding to the entry-exit position of the DNA arms identified earlier, H1 is capable of bridging of distant DNA segments. H1 binding leads to the assembly of mononucleosomes in aggregates, stabilized by internucleosome interactions as well as bridging of the DNA arms of chromatosomes. Contribution of these finding to the chromatin structure and functions are discussed.

Editorial: Institutional Repository of the Kyiv Medical University: A New Open Access Database for Authors and Peer-Reviewed Journals

Open access repository is a database, or a virtual archive established to collect, disseminate and preserve scientific output like scientific articles and datasets and to make them freely available. An institutional repository is one of four types of repositories. The purposes of this article are (1) to highlight the most important points of the Regulation on the Institutional Repository of the Kyiv Medical University (IRKMU) and (2) to explain the advantages for authors and peer-reviewed journals of colonization of the repository of such type. Also, this paper highlights the experience of the Department of Oral and Maxillofacial Surgery and the Journal of Diagnostics and Treatment of Oral and Maxillofacial Pathology (JDTOMP) in depositing peer-reviewed articles in this repository. The Regulation on the IRKMU was put into effect by Order No. 29 of January 26, 2024. In the same year, all structural units of the university, including dental departments, joined the process of depositing their scientific and clinical works. The IRKMU was created using the open-source software DSpace, which supports the Open Access Initiative Protocol for Metadata Harvesting (OAI-PMH) data exchange protocol, allowing the repository to be integrated into the international registers of the Registry of Open Access Repositories (ROAR), Directory of Open Access Repositories (OpenDOAR), and other search engines. The article is reinforced with screenshots of the stages of depositing data of scientific works. Carlile Butterfield and colleagues (2022) emphasized, that despite all benefits, however, their research indicates that it can be difficult to encourage all faculties to upload the research reports onto the institutional repository. Moreover, the authors propose a potential route to maximize the number of publications that are uploaded to a university institutional repository. They utilize student workers and the resources of the institutional repository manager to get materials uploaded. The experience of our department consists in attracting a competent editor from the editorial staff of the JDTOMP with appropriate payment for services. In sum, colonizing this new institutional repository as a new database, authors and peer-reviewed journals can and will increase the visibility of their publications. Thus, it can bear fruit in terms of increasing the citation of articles and the journals as well.

INFLUENCE OF MICROWAVE ACTIVATION OF COAL ON ITS PETROGRAPH-IC PROPERTIES

Despite the development of renewable sources, coal occupies an important place in the energy balance of many countries, especially those with large reserves. One of the ways to influence the characteristics of coal and add specified properties to it is its preliminary microwave activation. As a result of the studies, it was found that with microwave activation with an electromagnetic field power of 750 W for 240 s, an ambiguous effect on the characteristics of coal samples is observed, namely, coal with R0 greater than 1.16 before activation, microwave activation occurs faster, while the vitrinite reflectivity increases to 1.58 %, the yield of volatile substances and the thickness of the plastic layer decrease. Coals of a high stage of metamorphism are activated faster due to a denser structure. The presence of a more ordered structure than less metamorphosed coals, during the activation process, the condensed carbon layers come closer together, which ultimately increases their metamorphism stage. On the contrary, for coal with R0 less than 1.03 before activation, microwave activation is slower, while the vitrinite reflectance index decreases to 0.75 %, the yield of volatile substances and the thickness of the plastic layer increase. Obviously, this is due to the fact that coal of a low metamorphism stage is characterized by a less dense structure and more time is needed for its activation. Also, to increase the metamorphism stage, it is necessary to apply more energy so that the formed radicals and structural units connect with each other and form an ordered aromatic structure. Therefore, for coals of a low metamorphism stage, the activation time should be longer. The research results indicate the possibility of changing the coal metamorphism stage, which will increase the efficiency of coal processing processes, reduce energy costs and minimize harmful emissions due to the use of microwave technologies. In addition, the use of microwave activation can expand the raw material base for various coal technologies, especially in conditions of fuel shortage.

The place of the State Bureau of Investigation in the system of state law enforcement agencies of Ukraine

The article describes the place of the State Bureau of Investigation in the system of state bodies of Ukraine, in particular, the content of the categories “state bodies” and “public authorities” is defined, the system of state bodies is outlined, and the specifics of law enforcement agencies are clarified. It is noted that state bodies (public authorities) are characterised by their own specific features, among which the following are distinguished: a set of state bodies form the apparatus of the State, and therefore each of them is one of the elements of the integral system of the State apparatus; they are created and operate on the basis of relevant regulations, in the person of one person (citizen) or a group of citizens; each structural unit (state body) is endowed with unique powers of state power; they are created with the aim of performing tasks and It is also emphasised that the State Bureau of Investigation is a law enforcement agency. Therefore, the place of the State Bureau of Investigation in the system of state bodies is determined by its legal status as a central executive body, as evidenced by the specifics of its activities, since it was established for the special purpose of preventing and combating crimes committed by special categories of subjects, as well as war crimes, which is consistent with the law enforcement function of the state and has nothing to do with either legislative or judicial activities; as a law enforcement agency in view of the fact that its main and, in fact, the only task is to counteract criminal offences within its competence; as a state body with a special status, as evidenced by its tasks, powers and the fact that it carries out its activities independently and independently of other executive authorities in the organisational and functional aspect.

Communication systems with the meaning of affirmation and negation in the Tatar language

The article deals with one of the most controversial problems of Turkology, the problem of indivisible syntax, which manifests itself at the level of a simple and complex sentence. The relevance of the research is due to the fact that the linguistic analysis of the structure and semantics of communication makes it possible to substantiate the status of indivisible sentences in the syntactic system of the Tatar language and to identify the structural-semantic, grammatical, pragmatic aspects of indivisible sentences. The paper analyzes emotional and evaluative communicemes with affirmative and negative semantics in the Tatar language. The research material is semantic and emotionally expressive meanings of communicemes. The aim of the work is to identify and describe the most commonly used communicemes with affirmative and negative semantics in the Tatar language. The object of the study is the communicemes from the works of Tatar fiction, obtained by the continuous sampling method. The corpus of examples is represented by speech units of an indivisible structure, which we refer to the class of communicemes, that is, non-predicative units of syntax. The work revealed 15 affirmative and 10 negative communicemes in various lexical and grammatical variations. It has been established that communicemes with positive and negative semantics arise spontaneously in speech and are an expressive reaction of the speaker, accompanied by the intonation of delight, joy, surprise, anger, threats, etc. These syntactic units, being set phrases, express national specifics, therefore they are difficult to perceive for native speakers of other languages.

Preservative effects and mechanism of condensed tannins from Cercis chinensis Bunge leaves on fresh-cut lotus root.

This study aimed to investigate the potential of condensed tannins isolated from Cercis chinensis Bunge leaves as natural preservatives for fruits and vegetables. The research demonstrated that C. chinensis leaves condensed tannins (CLCT) significantly delay the browning process and reduce nutritional loss in fresh-cut lotus roots. Prodelphinidins were identified as the primary component of CLCT through electrospray ionization mass spectrometry and high-performance liquid chromatography analyses, with minor proportions of procyanidins and high levels of galloylation. The structural units predominantly consisted of (epi)gallocatechin. CLCT exhibited substantial inhibitory activity against tyrosinase, which may involve interactions with copper ions at the enzyme's active site and alterations in enzyme conformation, resulting in reversible inhibition. Additionally, CLCT displayed remarkable antioxidant and antibacterial properties, effectively scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'- azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and significantly inhibiting the growth of Pseudomonas aeruginosa and Staphylococcus aureus. Overall, the potential of CLCT as a natural preservative and tyrosinase inhibitor underscores its promising application in preserving fruits and vegetables.

Highly Selective, Catalyst‐Free, and Low Temperature Depolymerizable Styrene Copolymer With Incorporated α‐Methylstyrene Structural Units

ABSTRACTA simple strategy is proposed to offer styrene (St) copolymer with intrinsic and catalyst‐free upcycling capability by incorporating α‐methylstyrene (AMS) units into the copolymer poly(AMS‐co‐St) (PAS). Compared to polystyrene (PS), the PAS is more susceptible to depolymerizing into St and AMS monomers with higher yields at relatively lower temperature. The yield of liquid chemicals of PAS‐4 (26.1 mol% AMS) is up to 93 wt% at 380°C, whereas that PS as control is 78 wt%. The reclaimed liquid chemicals of PAS‐4 contain 58.4 wt% St and 37.7 wt% AMS, while the chemicals of PS contain 81.8 wt% St and 4.1 wt% AMS. The introduction of AMS units in PAS leads to a reduction in the liquid chemicals other than St and AMS monomers. The blends of PS and PAMS do not demonstrate the synergistic effect regarding facilitating the PS depolymerization. In addition, the properties of the new PASs prepared with the reclaimed monomers are comparable with those of the virgin PASs. This work proves the concept that recycling efficiency could be boosted by incorporating liable structural units into the copolymer chains and demonstrates a closed‐loop of PS up‐cycling.

Computational Characterization of the Structure, Energy, Strengths, and Fracture Resistances of Symmetric Tilt Grain Boundaries in Ice.

Using an interatomic potential that can capture the tetrahedral configuration of water molecules (H2O) in ice without the need to explicitly track the motion of the O and H atoms, coarse-grained (CG) atomistic simulations are performed here to characterize the structures, energy, cohesive strengths, and fracture resistance of the grain boundaries (GBs) in polycrystalline ice resulting from water freezing. Taking the symmetric tilt grain boundaries (STGBs) with a tilting axis of ⟨0001⟩ as an example, several main findings from our simulations are (i) the GB energy, EGB, exhibits a strong dependence on the GB misorientation angle, θ. The classical Read-Shockley model only predicts the EGB - θ relation reasonably well when θ < 20° or θ > 45° but fails when 20° < θ < 45°; (ii) two "valleys" appear in the EGB-θ landscape. One occurs at θ = 22° for Σ14(2̅31̅0) GB, and the other is at θ = 32° for Σ26(3̅41̅0) GB. These two GBs might be the most common in polycrystalline ice; (iii) all the STGB structures under consideration here are found to be a collection of edge dislocations with a Burgers vector of b = 1/3⟨112̅0⟩. The core structure of this edge dislocation is composed of a pentagon and a heptagon atomic ring. The separation and orientation of the structure units (SUs) at the GB exhibit a strong dependence on θ; (iv) the length of an atomic bond within the SUs, rather than EGB and θ which are often used in the literature, is identified as one controlling parameter that dictates the intrinsic GB cohesive strength; (v) characterization of the fracture resistance of the GB containing an initial crack is beyond the reach of nanoscale atomistic simulations but is feasible in concurrent atomistic-continuum (CAC) simulations that can simultaneously retain the atomic GB structure together with the long-range stress field within one model. The above findings provide researchers with a stepping stone to understand the complex microstructure of polycrystalline ice and its response to external forces from the bottom up. Such knowledge may be consolidated into constitutive rules and then transferred into the higher length scale models, such as cohesive zone finite element models (CZFEMs), for predicting how polycrystalline ice fractures at laboratory and even geophysical length scales.