Mixed Basis Research Articles

Empirical, computational studies and non-covalent interactions analysis of a novel salt with cadmium transition metal precursor

In this research paper, (C3H5N2)6[CdCl4][CdCl6] was successfully synthesized using a slow evaporation process. The structure was confirmed through single-crystal X-ray crystallography, FT-IR, and thermal analysis. The material was found to crystallize in the tetragonal system (space group I41/a) and the following parameters a = b = 12.0872 (8) Å; c = 24.6985 (16) Å, the crystal packing shows parallel layers of cations and stacks of discrete anions positioned at y = 1/4 and 3/4. The junction between the monoprotonated imidazolium cations and the anions, along with the crystal structure stability, relies on Cl···H−N, and Cl···H−C hydrogen bonds. Computational investigations, conducted using the B3LYP method with 6–311++G(d,p) and LANL2DZ mixed basis set, demonstrated close alignment between the computed and the experimental data, providing insights into the material's geometrical and vibrational properties. The non-covalent interactions were studied through Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analysis and quantitatively using the Hirshfeld surfaces associated with 2D fingerprint plots. Furthermore, thermal stability was assessed through Thermogravimetric and Differential Scanning Calorimetry (TG–DSC) analysis.

Unraveling Strong Supramolecular Assembly of a Novel Pyrene Based Hg(II)‐complex: Insights from Hirshfeld Surface, FMO and Molecular Electrostatic Potential (MEP) Analyses

AbstractA rare pyrene‐based coordination compound of Hg(II) [Hg(L)2] (1) (where, HL=2‐((Pyren‐1‐ylmethylene)amino)benzenethiol) was synthesized and characterized by single crystal X‐ray diffraction (SC‐XRD) analysis. Crystallographic analysis revealed that complex 1 has seesaw geometry with HL coordinated as a bidentate ligand to a metal ion. The role of weak forces like π⋅⋅⋅π and CH⋅⋅⋅π interactions in influencing the self‐assembly process appears to be of importance. The electronic structure of the complex was predicted using DFT calculations with mixed basis set. DFT calculated structural parameters are in good agreement with the experimentally obtained parameters from XRD. Molecular reactivity and stability of the complex has been assessed through frontier molecular orbital analysis. Evaluation of molecular electrostatic potential (MEP) displays the electrophilic and nucleophilic reactivity sites. The Hirshfeld surface analysis clearly indicates C−H⋅⋅⋅π interactions and π⋅⋅⋅π stacking interactions are responsible to extend the supramolecular network of the complex. Analyses of the Finger print plots suggest that H⋅⋅⋅H and H⋅⋅⋅C contacts are major interactions for stabilizing the molecular crystal.

Supramolecular polyplexes from Janus peptide nucleic acids (bm-PNA-G5): self-assembled bm-PNA G-quadruplex and its tetraduplex with DNA.

Nucleic acids (DNA and RNA) can form diverse secondary structures ranging from hairpins to duplex, triplex, G4-tetraplex and C4-i-motifs. Many of the DNA analogues designed as antisense oligonucleotides (ASO) are also adept at embracing such folded structures, although to different extents with altered stabilities. One such analogue, peptide nucleic acid (PNA), which is uncharged and achiral, forms hybrids with complementary DNA/RNA with greater stability and specificity than DNA:DNA/RNA hybrids. Like DNAs, these single-stranded PNAs can form PNA:DNA/RNA duplexes, PNA:DNA:PNA triplexes, PNA-G4 tetraplexes and PNA-C4-i-motifs. We have recently designed Janus-like bimodal PNAs endowed with two different nucleobase sequences on either side of a single aminoethylglycyl (aeg) PNA backbone and shown that these can simultaneously bind to two complementary DNA sequences from both faces of PNA. This leads to the formation of supramolecular polyplexes such as double duplexes, triple duplexes and triplexes of double duplexes with appropriate complementary DNA/RNA. Herein, we demonstrate that Janus/bimodal PNA with a poly G-sequence on the triazole side of the PNA backbone and mixed bases on the t-amide side, templates the initial formation of a (PNA-G5)4 tetraplex (triazole side), followed by the formation of a PNA:DNA duplex (t-amide side). Such a polyplex shows synergistic overall stabilisation compared to the isolated duplexes/quadruplex. The assembly of polyplexes with a shared backbone for duplexes and tetraplexes is programmable and may have potential applications in the self-assembly of nucleic acid nano- and origami structures. It is also shown that Janus PNAs enter the cells better than the standard aeg-PNA oligomers, and hence have implications for in vivo applications as well.

Significantly enhanced high-temperature energy storage performance for polymer composite films with gradient distribution of organic fillers

Film capacitors as one of the most important electronic devices are heading in large capacity, heightened integration and excellent extreme-condition tolerance, which faces the challenges in maintaining outstanding performance under harsh conditions of high temperature and large electric field. Nonetheless, polymer capacitive films, which are renowned for their exceptional thermal stability, experience an escalation in conduction losses at elevated temperatures, resulting in degradation of energy storage performance. This study presents the gradient distribution of organic fillers content in all-organic polymer capacitive films utilizing electrospinning technique, the significantly improved high-temperature energy storage performance has been achieved. Glucose (GLC), a weak polar molecule rich in hydroxyl groups, is blended with the most promising polyetherimide (PEI). Experimental and theoretical calculations confirm that the formed hydrogen bond between GLC and PEI acts as a trapping site for capturing carriers and suppressing conduction losses. Furthermore, the spatial distribution of organic fillers was designed on the basis of direct mixing. The results demonstrate that the gradient composite film introduces interlayer interfacial polarization, while the dielectric mismatch between adjacent layers increases the height of potential barriers for the charge carriers across the interfaces, thereby achieving a synergistic enhancement of dielectric response and insulation strength. The maximum discharge energy density of 6.52 J/cm3 with an efficiency of 85.6 % has been achieved at 150℃ for the modified capacitive films. This work establishes a decoupling relationship between permittivity and electric breakdown strength, offering insights for the advancement of polymer films with outstanding energy storage capabilities in extreme environments.

A classifier based on mixed radial basis function network and combinatorial optimization model for medical diseases diagnosis

A classifier based on mixed radial basis function network and combinatorial optimization model for medical diseases diagnosis

Exploration of supramolecular interactions, Hirshfeld surface, FMO, molecular electrostatic potential (MEP) analyses of pyrazole based Zn(II) complex

The supramolecular interactions of title compound [Zn(HL2)](ClO4)2(MeOH)2] (1) where, HL2=((Z)-N’-(5-methyl-1H-pyrazole-3-carbonyl)pyrazine-2-carbohydrazonamide) are explored in detail. With a detailed scrutiny of visualizing of title compound 1, the crystal packing is mainly directed by strong hydrogen bonding interactions observed N–H⋯N and N–H⋯O but, in addition, weak interactions such as C–H⋯π, π⋯π are also sighted to stabilize the crystal self-assembly. Electronic structure of the complex is determined using DFT calculations at B3LYP level with mixed basis set. Theoretically calculated structural parameters are in good match with the experimentally obtained parameters from XRD. TDDFT calculation is performed to simulate the UV–Vis absorption spectra of the complex. Molecular reactivity and stability of the complex has been assessed through frontier molecular orbital analysis and also through evaluation of molecular electrostatic potential (MEP). Hirshfeld surface analysis, which uses molecular surface contours and 2D fingerprint plots to visually analyze intermolecular interactions in crystal structures, has been used to examine molecular morphologies. The Hirshfeld surface and fingerprint plots are accompanied by crystal structure analysis allowed for the discovery of the important intermolecular interactions.

Typology of pedagogical situations: cross-cultural analysis

Importance. The natural appeal to the possibility of defining certain typological features that would contribute to the differentiation of pedagogical situations leads to the need for a certain systematization of knowledge and experience. It is relevant to consider and compare the classification basis of typologies, since there is still no certainty about how a pedagogical situation should be described.Research methods. The comparative analysis, the content analysis, the method of interpretation and contextual analysis.Result and Discussion. The analyzed typologies of pedagogical situations in Russian pedagogy differ in typological basis, principles, understanding of the essence of pedagogical situations, which makes their systematization ambiguous, complex and practically impossible to use in everyday pedagogical practice. Foreign typologies of pedagogical situations are built on fundamentally different grounds, based on the understanding of the essence of the educational process, participants and the nature of changes. The analysis has shown that all the studied typologies of situations do not simplify the use and systematization of pedagogical situations, but being built on mixed basis, bring confusion in understanding and operating of pedagogical situations.Conclusion. The diversity of descriptions and ambiguity of definitions of pedagogical situations makes it difficult to create a complete typology and choose the clear basis. Based on our definition of the pedagogical situation, we considered it possible to propose clearer and more systematic basis for typology and to identify 3 types of pedagogical situations. Such a logical basis can be the ability of a pedagogical situation to reach the solution of a pedagogical task. Unlike all the analyzed situations, the proposed typology is based on clear systemic typological basis, allows differentiating and ordering of pedagogical situations, is easy to use.

Dominant Mixed Metric Dimension of Graph

For $k-$ordered set $W=\{s_1, s_2,\dots, s_k \}$ of vertex set $G$, the representation of a vertex or edge $a$ of $G$ with respect to $W$ is $r(a|W)=(d(a,s_1), d(a,s_2),\dots, d(a,s_k))$ where $a$ is vertex so that $d(a,s_i)$ is a distance between of the vertex $v$ and the vertices in $W$ and $a=uv$ is edge so that $d(a,s_i)=min\{d(u,s_i),d(v,s_i)\}$. The set $W$ is a mixed resolving set of $G$ if $r(a|W)\neq r(b|W)$ for every pair $a,b$ of distinct vertices or edge of $G$. The minimum mixed resolving set $W$ is a mixed basis of $G$. If $G$ has a mixed basis, then its cardinality is called mixed metric dimension, denoted by $dim_m(G)$. A set $W$ of vertices in $G$ is a dominating set for $G$ if every vertex of $G$ that is not in $W$ is adjacent to some vertex of $W$. The minimum cardinality of dominating set is domination number , denoted by $\gamma(G)$. A vertex set of some vertices in $G$ that is both mixed resolving and dominating set is a mixed resolving dominating set. The minimum cardinality of mixed resolving dominating set is called dominant mixed metric dimension, denoted by $\gamma_{mr}(G)$. In our paper, we will investigated the establish sharp bounds of the dominant mixed metric dimension of $G$ and determine the exact value of some family graphs.

Adding experiments to the classical survey-interview mix: A three-method design for supporting micro-to-macro explanations in sociology

The aim of this programmatic article is to spell out a three-method design for supporting micro-to-macro explanations based on social mechanisms. In this design, the experimental method is called on to strengthen the explanatory basis of the common survey-interview mix, against the background of growing interest in causal inference and experimentation across the social sciences. The proposal is articulated through the specific problem of the contribution of discrimination (micro process) to the generation of inequalities in mental health (macro outcome) between culturally stigmatized and non-stigmatized groups (macro predictor). The article motivates the research problem and the three-method design, offering a detailed discussion of the limitations of survey-based measures of perceived discrimination. Drawing on the literature on mixed methods, the relationships between the survey, the interview-based study and the field experiment are analyzed in terms of triangulation, development, and complementarity. The broader applicability of the proposed three-method design is illustrated with examples from the distinct fields of civic engagement and labor market inequalities.

DFT investigation of Pt-doped CTF-1 covalent triazine frameworks for adsorption and sensing of SF6 decomposition products

We report a computational investigation of the gas adsorption and sensing properties of pristine covalent triazine framework CTF-1 and its platinum atom (Pt)-doped counterpart towards SF6 decomposition products (i.e., H2S, SO2, SOF2, and SO2F2 gases). For this purpose, density-functional theory calculations are employed with the TPSS exchange-correlation functional (with the Grimme-D3 empirical dispersion correction) and a 6-31+G**/Lanl2DZ mixed basis set. Pt was found to interact with a nitrogen atom, distorting the planar structure. Our results reveal that the electronic bandgap of the pristine CTF-1 lowers noticeably following surface doping with a Pt atom (3.48 vs. 1.06 eV for pristine vs. Pt-doped CTF-1, respectively), enhancing the electrical conductivity of the gas sensor. In contrast to pristine CTF-1, which displays weak adsorption performance (with adsorption energies of −0.25, −0.27, −0.31, and −0.18 eV for H2S, SO2, SOF2, and SO2F2, respectively), Pt-doped CTF-1 exhibits strong interactions with the gas species (with adsorption energies of −1.93, −2.41, −6.27, and −7.98 eV for H2S, SO2, SOF2, and SO2F2, respectively) and high sensitivity in detecting the target gas species under study. Moreover, a density of states (DOS) analysis is conducted to further characterize the mechanisms involved in gas adsorption and sensing. All four degradation products decrease the bandgap of pristine CTF-1 and increase the bandgap in Pt-doped CTF-1. The latter is generally more pronounced. We conclude that Pt-doped CTF-1 could be a novel SF6 decomposition gas adsorbent and sensor and provide experimentalists with the essential physicochemical characteristics of the designed materials for future work.

Syntheses, Crystal Structure and Theoretical Properties of Schiff Bases Obtained from Isoniazid and Pyridine‐2‐, 3‐, 4‐Carboxaldehyde and Their Zinc(II) Complexes

AbstractThe series of Schiff base ligands, N’‐(pyridine‐2‐ylmethylene)isonicotinohydrazide (I), N’‐(pyridine‐3‐ylmethylene)isonicotinohydrazide (II) and N’‐(pyridine‐4‐ylmethylene)isonicotinohydrazide (III), and the Zn(II) complexes of the ligands (I and II), [N’‐(pyridine‐2‐ylmethylene)isonicotinohydrazide]‐trichlorozincoate (IV) and [N’‐(Pyridin‐3‐ylmethylene) isonicotinohydrazide] trichlorozincoate (V) have been newly synthesized and their structures have been characterized by 1H, 13C NMR and FT‐IR spectroscopies, elemental analysis and single crystal X‐ray diffraction technique. The Hirshfeld surface analyses have been confirmed the importance of H‐atom contacts in establishing the packings. The ground state equilibrium geometries of the synthesized compounds are optimized at DFT/B3LYP/6‐311++G (d, p) and HF/6‐311++G (d, p) levels of theory (for the ligands) and B3LYP/GENECP method is used as the mixed basis sets of LANL2DZ (for Zn) and 6–311G (for other atoms) in the gas‐phase. The structural parameters obtained from the theoretical studies of the compounds are compared with their experimental ones. Their linear and nonlinear optical (NLO) properties are also calculated by the same methods. In the ground state, the energy band gaps (Eg) of the Schiff bases (I, II and III) have been calculated as 4.38 eV, 4.36 eV and 4.46 eV (at B3LYP) and 9.94 eV, 9.81 eV and 10.20 eV (at HF), respectively.

ANOVA approximation with mixed tensor product basis on scattered points

In this paper we consider an orthonormal basis, generated by a tensor product of Fourier basis functions, half period cosine basis functions, and the Chebyshev basis functions. We deal with the approximation problem in high dimensions related to this basis and design a fast algorithm to multiply with the underlying matrix, consisting of rows of the non-equidistant Fourier matrix, the non-equidistant cosine matrix and the non-equidistant Chebyshev matrix, and its transposed. Using this, we derive the ANOVA (analysis of variance) decomposition for functions with partially periodic boundary conditions through using the Fourier basis in some dimensions and the half period cosine basis or the Chebyshev basis in others. We consider sensitivity analysis in this setting, in order to find an adapted basis for the underlying approximation problem. More precisely, we find the underlying index set of the multidimensional series expansion. Additionally, we test this ANOVA approximation with mixed basis at numerical experiments, and refer to the advantage of interpretable results.

Synthesis of 2-amino-5-methylpyridinium tetrachloridocadmate(II) (C6H9N2)2[CdCl4]: Structure, DFT-calculated descriptors and molecular docking study

In this research paper, (C6H9N2)2[CdCl4], was effectively synthesized using the slow solvent evaporation procedure. Single crystal X-ray diffraction (scXRD) analysis revealed that the compound crystallizes in the triclinic system, specifically in the space group P1¯. Powder XRD (PXRD) of the bulk material showed some minor impurities. The atomic arrangement of the title structure comprises discrete tetrahedral groups [CdCl4]2− linked to the organic entities through weak N(C)H…Cl hydrogen bonds. Solid-state contacts were further studied through Hirshfeld surface analyses, complemented by 2D fingerprint plots. Computational results, obtained using the B3LYP tool with 6-311++G(d,p) + LANL2DZ mixed basis set, demonstrated consistent geometrical, vibrational, and electronic features to the experimental data. Non-covalent interactions were explored in depth using Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analyses. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) analyses showed melting at 378 K and decomposition at around 540 K. Furthermore, the inhibition activity of the examined compound was explored in-silico through molecular docking studies targeting the inducible Nitric Oxide Synthase (iNOS) enzymes.

Investigating the third-order nonlinear optical properties of a Schiff base (DBAP) and its Co/Cu metal complex using Z-scan and DFT methodology

Utilizing UV-visible, Fluorescence spectroscopic, and Z-scan methods, the optical and structural properties of 2-(4-(dimethyl amino)benzylidene amino) phenol (DBAP) and their Co/Cu metal complexes were studied. The Z-scan method has been used to investigate the nonlinear absorption coefficient (β), nonlinear refractive index (n2), third-order susceptibility (χ(3)), and optical limiting (OL). In dimethyl sulfoxide (DMSO) and methanol (MeOH) solvents, the DBAP and their Co/Cu metal complexes display positive nonlinear absorption and a positive nonlinear refractive index, according to the Z-scan data. Using the Z-scan approach and an 800 nm central wavelength, femtosecond amplified 48 fs pulse, 1kHz repetition rate laser, the compound's third-order nonlinear optical (NLO) properties are measured. According to the Z-scan data, we may modify the structure and bonding of legend with metals to improve the NLO capabilities of metal complexes, making this material a promising choice for upcoming optoelectronic and photonic devices. The geometrical structure of the compound is optimized using theoretical computations at the B3LYP that are functional with 6-31G and the LanL2DZ on a mixed basis, as determined by the density functional theory (DFT) framework. They provide insight into the charge transfer interactions taking place in the molecule through their HOMO-LUMO analysis.

First-principles calculations to investigate structural, elastic and electronic properties of chloro-perovskite NaMgCl3

In this work, we have investigated the structural, electronic, and optical properties of the halide-perovskite NaMgCl3 by performing first-principles calculations using a mixed basis of the full-potential linearized augmented plane wave (FP-LAPW) approach under the generalized gradient approximation (GGA-PBEsol), a revised Perdew-Burke-Ernzerhof, and the modified Becke-Johnson (TB-mBJ) implemented on the Wien2k package. The obtained results show that NaMgCl3 is more stable in the nonmagnetic phase.The compound is found to be thermodynamically and elastically stable. It is found that there is a good agreement between the calculated lattice constants and the values published in previous studies. The complete set of first-order elastic constants tensor has been calculated, implying mechanical stability. The Young's modulus, shear modulus, Poisson's ratio,Pugh's ratio, and universal anisotropy index have been additionally calculated. The atomic bonds along both x and y axis are stronger than those along the z-axis. The Debye temperature is calculated using the average sound velocity. From electronic band structures, we have found that NaMgCl3 is an insulator with a direct wide band gap ΓV→ΓC. The electronic charge densities were plotted.Analysis of the charge density distribution map reveals that the bondings in NaMgCl3 are ionic. The calculated density of states (DOS) indicates that the valence band is mainly dominated by Cl− anions, the conduction band is mainly dominated by Mg2+ cations, whereas Na+ has a negligible contribution. The optical characteristics, notably the dielectric function tensor, refractive function, reflectivity, absorption coefficient, photo-conductivity and transmittance were plotted and discussed. The optical properties confirm that NaMgCl3 is optically anisotropic in 10–24 eV range .The low transmittance and high absorption coefficient in the far ultra-violet region, between 90 and 250 nm, make this compound a good candidate for use as an ultraviolet shield, in vacuum ultraviolet lenses and in thermoelectric promising features due to his direct wide band gap.Experimental and theoretical data are scarce for this compound in an ilmenite-type structure.

On Vertex-Edge Resolvability for the Web Graph and Prism Related Graph

Let E ( H ) and V ( H ) denote the edge set and the vertex set of the simple connected graph H , respectively. The mixed metric dimension of the graph H is the graph invariant, which is the mixture of two important graph parameters, the edge metric dimension and the metric dimension. In this article, we compute the mixed metric dimension for the two families of the plane graphs viz., the Web graph W n and the Prism allied graph D t n . We show that the mixed metric dimension is non-constant unbounded for these two families of the plane graph. Moreover, for the Web graph W n and the Prism allied graph D t n , we unveil that the mixed metric basis set M m G is independent.

Dry mixes on gypsum and mixed bases in the construction of low-rise residential buildings using 3D printing technology

3D-printed building construction technology is developing in most countries, such as France, China, Russia and others, and the dry mixes and equipment used are being improved. The development of 3D-printing construction technology is dictated by its many advantages: architectural diversity, speed and automation of the technological process of construction of buildings and structures with a noticeable reduction in the cost of production. However, there are a number of problems of this technology that are waiting for optimal solutions. The paper proposes solutions to two such problems: firstly, the choice of mixture with gypsum and gypsum-cement binders, ensuring the continuity of the 3D printing process of the building and allowing the construction of buildings up to three floors with sufficient safety margin, high seismic stability, as well as with good heat and noise insulation; secondly, the design of buildings with a rational structural and technological solution of the roof and floor, allowing the interface of these structures with load-bearing printed walls. Different compositions of dry mixes were tested in a series of field tests of large-sized wall blocks made with the use of a construction 3D-printer and filled with especially light porous expanded claydite, expanded clay concrete or heat-insulating foam gypsum with subsequent testing on press equipment of increased load-carrying capacity (with determination of bearing capacity and deformability of the large-sized block). When designing low-rise buildings, erected by additive technology, as an optimal design of floors, it is proposed to use frame-monolithic beam structures made of metal thin-walled steel galvanized profiles, filled with foam gypsum mix, providing heat and noise insulation and covered with a thin layer of high-strength self-leveling gypsum mix, providing the necessary structural strength of the floor and, accordingly, the minimum load on the foundation.

Separation of Input Variables for Optimization of the Mealy FSM Circuit

Introduction. One of the most important blocks of almost any digital system is the control device (CU), since the characteristics of the CU largely determine the characteristics of the system as a whole. In the practice of engineering design, the behavior of the CU is often specified using the Mealy finite state machine (FSM) model. A feature of Mealy FSM is the dependence of systems of Boolean functions that define the circuit on FSM inputs and states. In this article, this feature is taken into account when optimizing the characteristics of FSM circuit in the basis of FPGA chips. When developing FSM circuits, it is necessary to optimize its characteristics, such as performance and hardware costs. FPGAs are one of the most common logic bases for implementing digital systems. FPGA components such as look-up table (LUT) elements, programmable flip-flops, embedded memory blocks (EMBs), and programmable interconnects are sufficient to implement the CU circuit. The purpose of the article. In this paper, we propose a method for reducing hardware costs in the Mealy FSM cirucit implemented in the FPGA basis. In this case, the problem of implementing a circuit in a mixed elemental basis is considered. A mixed basis is understood as the joint use of LUTs and EMBs. The situation is considered when the number of available EMBs is extremely limited, which is quite possible, since EMBs are widely used to implement various operating blocks of digital systems. The main disadvantage of LUTs is the small number of inputs. Modern digital systems can generate signals of logical conditions entering the CU, the number of which is tens of times greater than the number of LUT inputs. This discrepancy between the characteristics of the control algorithm and the number of inputs of the LUTs leads to multilevel CU circuits with an irregular structure of programmable interconnections. To optimize multilevel schemes, the method of replacing input variables is used with the joint use of LUTs and EMB blocks. Results. The analysis of the effectiveness of the proposed method was carried out using the libraries of standard benchmarks FSMs and the Vivado CAD platform. Studies have shown that the proposed method makes it possible to reduce the number of LUTs in the range from 100% to 82%. For 37% of automata, the method of replacing input variables can be applied only in conjunction with the separation of input variables. Conclusions. The proposed method makes it possible to reduce hardware costs (the number of LUTs and their interconnections), delay time, and power consumption. The article shows the conditions for applying the proposed method. The results of studies of the effectiveness of the proposed method for standard automata using chips of the Virtex-7 family and the Vivado industrial package are presented. Keywords: finite state machine, synthesis, FPGA, EMB, LUT, input replacement.

Marketing policy of farms in Ukraine

Unequal conditions for the functioning of farms as a part of agricultural sector require strategic thinking and marketing orientation from farmers. The limited use of marketing tools in the management activities of farmers is associated with insufficiently adapted marketing provision for the specifics of farming. The aim of the article is to substantiate the marketing provision of the strategic development of farming based on a rational combination of optimal elements of modification models of the marketing mix. The theoretical and methodolo­gical basis of the research was made up of the fundamental positions of the general economic theory, the system-structural analysis of econo­mic processes, the results of the scientists’ work on the researched issues. Monographic, abstract-logical, graphic methods, analysis and synthesis, analogy, theory of rational choice, methods of points, expert evaluations, combi­ning, analytical hierarchy, and statistical proces­sing of information were used in the research process. Prerequisites of the marketing type of farm management are determined. Based on the generalization of the problems of farming in modern conditions, the expediency of using strategic marketing tools in the process of its activity is argued. The meaning and significance of marketing provision in the development of farming is revealed. A model of the farm marketing complex has been created. The marketing support of farming is substantiated, within which examples of the use of strategic tools are given. Farms that use strategic marketing have the advantages of successful adaptation to the market, different from their competitors. The application of reasonable marketing provision for the development of farming on the basis of a marketing mix adapted to the specifics of farming expands its possibilities and strategic horizons as a progressive business form.

Detection of Aromatic Hydrocarbons in Aqueous Solutions Using Quartz Tuning Fork Sensors Modified with Calix[4]arene Methoxy Ester Self-Assembled Monolayers: Experimental and Density Functional Theory Study.

Quartz tuning forks (QTFs), which were coated with gold and with self-assembled monolayers (SAM) of a lower-rim functionalized calix[4]arene methoxy ester (CME), were used for the detection of benzene, toluene, and ethylbenzene in water samples. The QTF device was tested by measuring the respective frequency shifts obtained using small (100 µL) samples of aqueous benzene, toluene, and ethylbenzene at four different concentrations (10-12, 10-10, 10-8, and 10-6 M). The QTFs had lower limits of detection for all three aromatic hydrocarbons in the 10-14 M range, with the highest resonance frequency shifts (±5%) being shown for the corresponding 10-6 M solutions in the following order: benzene (199 Hz) > toluene (191 Hz) > ethylbenzene (149 Hz). The frequency shifts measured with the QTFs relative to that in deionized water were inversely proportional to the concentration/mass of the analytes. Insights into the effects of the alkyl groups of the aromatic hydrocarbons on the electronic interaction energies for their hypothetical 1:1 supramolecular host-guest binding with the CME sensing layer were obtained through density functional theory (DFT) calculations of the electronic interaction energies (ΔIEs) using B3LYP-D3/GenECP with a mixed basis set: LANL2DZ and 6-311++g(d,p), CAM-B3LYP/LANL2DZ, and PBE/LANL2DZ. The magnitudes of the ΔIEs were in the following order: [Au4-CME⊃[benzene] > [Au4-CME]⊃[toluene] > [Au4-CME]⊃[ethylbenzene]. The gas-phase BSSE-uncorrected ΔIE values for these complexes were higher, with values of -96.86, -87.80, and -79.33 kJ mol-1, respectively, and -86.39, -77.23, and -67.63 kJ mol-1, respectively, for the corresponding BSSE-corrected values using B3LYP-D3/GenECP with LANL2dZ and 6-311++g(d,p). The computational findings strongly support the experimental results, revealing the same trend in the ΔIEs for the proposed hypothetical binding modes between the tested analytes with the CME SAMs on the Au-QTF sensing surfaces.