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Rational compositions of a polymer composite material are proposed and technological prerequisites for manufacturing technical products for chemical engineering, based on liquid resol phenol–formaldehyde resins and dispersed fibrous filler manufactured by mechanical processing of the organic waste from fiber production in the pulp and paper industry are evaluated. Methods and parameters of technological stages, including the preparation of raw materials and their mixtures, production of a polymer dispersed filled press material, and hot molding (pressing) products, were determined and tested. Recommendations are given on the hardware and process design of the technological stages of the production of a quality polymer composite material and improvement of its properties. The regularities of changes in the physical and mechanical properties (response on compression, tension, and bending, as well as impact strength and moisture and oil absorption) of the composites with the concentration of dispersed fibrous filler at the recommended thermal pressing parameters (temperature 170 °C, specific pressure 20 MPa, exposure time 1 min/ 1 mm product thickness). Clear evidence is provided showing that the upper limit of the percentage of dispersed fibrous filler in the studied phenolic samples is 40-60%, and at higher percentages the mechanical parameters are strongly deteriorated and the moisture and oil absorptions become much higher than the limits permitted by standards for technical phenolic plastics. The results of the study make it possible to recommend the compositions based on liquid resol phenol–formaldehyde resins and modified fibrous waste from the pulp and paper industry and the hardware and process design for the production of phenolic products of chemical engineering. The developed composites allow homogeneous coloring in various colors (except for white) and imparting to their surface a smooth shiny texture. [ABSTRACT FROM AUTHOR]

Recent increase in curiosity regarding behavior of two-dimensional layered materials leads the scientists worldwide to explore various physico-chemical properties of these materials. Promising application of MoS2 as electrode material for various electrochemical devices prompted our group to investigate and compare the electrochemical nature of bare glassy carbon electrode with that of PANI/ MoS2 modified glassy carbon electrode. PANI is preferred over other materials in electrochemical applications owing to its unique properties as conductive polymer. In this paper, a comparison of the voltammetric response of dopamine has been explored on both the electrodes. The study indicates that the voltammetric response is slightly better in case of modified glassy carbon electrode in comparison to bare electrode. Study also shows that the effect of adsorption is also observable on both the electrodes from concentration of 0.4 µM onwards. The outcome of this paper holds significant implications for a wide range of electroanalytical applications, biomedical sensing and other chemical analysis. [ABSTRACT FROM AUTHOR]

The paper considers the regularities of the processes of fixing dispersed dyes on fabrics under conditions of sublimation printing, depending on the nature of the modifiers used for the preliminary processing of textile materials. The authors determined the optimal conditions for thermal transfer of dyes to fabric, selected the most effective modifiers that provide the highest color yield on fabrics, durability of dyes and achieve environmental safety of products. [ABSTRACT FROM AUTHOR]

The use of metal complexes has significantly advanced in the treatment of a variety of diseases. The complexes of iron, copper, cobalt, gold, titanium, ruthenium, gallium or platinum atoms have shown various medicinal activities such as anticancer, antimicrobial, antibacterial, antioxidant, antifungal and antiviral etc. However, many existing metal complexes have serious drawbacks such as lipophilicity, low water-solubility and toxicity etc. Currently, these therapeutic agents are usually solubilized using increase concentrations of surfactants and co-solvents, which often lead to unfavourable effects. Recently, researchers have been focusing on investigating the use of nanotechnology as an option to overcome these side effects. Nanoparticles (NPs) and nano medicines require less amount of drug dose which help in reducing the load of metal in the body. The NPs are reported to be less harmful when used for gene and medication delivery. Literature survey shows that nano formulation of drugs improves their characteristics and synergistic functionality. Several classes of nanocarrier systems are broadly demonstrated for packaging and administration of the novel and established drug. These nanocomposites are also been demonstrated to have a numerous other benefit, including decreased tumour growth, decreased systemic toxicity and increased therapeutic efficacy. This review paper has summarized recent developments in the field of nanotechnology and nanofabrication of metals, and their compounds for effective medicinal and environmental applications. The literature was reviewed and collected from leading indexing databases of last 10 years to find how the nanofabrication of metals improves the efficacy. The review paper may help the researchers to come up with effective and non-hazardous solutions in the field of medicinal and environmental chemistry. [ABSTRACT FROM AUTHOR]

Anticancer chemotherapeutics are effective weapons for cancer therapy, but the continuous emergency of multidrug-resistant cancer and the side effects of current available anticancer chemotherapeutics are the major obstacles in the control and eradication of cancers. Pyrrolo[2,3-d]pyrimidines could inhibit signal transduction cascades affecting cell proliferation, migration, and angiogenesis, representing privileged scaffolds for the discovery of novel anticancer candidates. This review highlighted the recent developments of pyrrolo[2,3-d]pyrimidines with anticancer potential and discussed mechanisms of action, covering papers published from 2018 to present, to facilitate further rational design of more effective candidates. [ABSTRACT FROM AUTHOR]

The selective oxidation of tetrahydrofuran to γ-butyrolactone is an efficient method to convert biomass derivatives into high-value chemicals. In order to improve the efficacy of conversion of tetrahydrofuran to γ-butyrolactone, this study prepared an Ag–CeO2/α-Al2O3 catalyst via the impregnation method and used a solvent-free approach to convert tetrahydrofuran to γ-butyrolactone. And the conversion rate of 100% of raw material was achieved. The prepared catalyst was characterized by TEM, XRD, N2 adsorption-desorption and XPS, in order to better understand the performance of the catalysts. The results demonstrated that Ce3+ and Ce4+ coexist on the surface of the catalyst and verified the existence of metallic Ag (Ag0) in Ag–CeO2/α-Al2O3 catalyst. The reaction mechanism of the formation of γ-butyrolactone by γ-site switch (ring-opening and ring-closing) of tetrahydrofuran was deduced. This is attributed to the synergistic action of Ag and Ce. γ-Site switch effect (ring-opening and ring-closing) is proposed for the first time in this paper. [ABSTRACT FROM AUTHOR]

Cancer, caused by the failure of the mechanism that controls cell growth and proliferation, is usually associated with severe health issues. Nowadays, chemotherapy still occupies an important place in clinical cancer treatment, but the multidrug resistance and low specificity of chemotherapeutics are the major obstacles that undermine effective cancer treatment. Pyrazole and pyrimidine/fused pyrimidine can be rewarded with significant anticancer activity and tampered with in a range of places whereby some of their derivatives have received approval to treat cancer. Notably, pyrazole-pyrimidine/fused pyrimidine hybrids, blending of pyrazole and pyrimidine/fused pyrimidine pharmacophores into in a new chemical entity, can act on different targets simultaneously in cancer cells and possess potent in vitro and in vivo activity against both drug-sensitive and drug-resistant cancers. Moreover, several pyrazole-pyrimidine/fused pyrimidine hybrids which are exemplified by ruxolitinib (pyrazole-pyrrolo[2,3-d]pyrimidine hybrid) have already applied in clinics for cancer therapy, demonstrating pyrazole-pyrimidine/fused pyrimidine hybrids are pharmacologically significant scaffolds for the exploration of novel anticancer agents. This review aims to shed light on the recent developments of pyrazole-pyrimidine/fused pyrimidine hybrids with anticancer potential, and their structure-activity relationships as well as mechanisms of action are also discussed, covering papers published from 2019 to present, to facilitate further rational design of more effective candidates. [ABSTRACT FROM AUTHOR]

Four coordination polymers were synthesized by two fluorescently active metal Zn/Cd(II) via pyrazinamide-based ligand [N,N′-bis[(3-pyridyl)arylphenolone]piperazine (L) and mono-/di-carboxylic acids under hydrothermal conditions, namely, [Zn(L)(HPTA)2(H2O)], [Cd(L)(HPTA)2(H2O)]∙2H2O, [Zn(L)0.5(1,4-H2BDC)(H2O)]∙H2O, [Cd(L)0.5(1,4-H2BDC)(H2O)]∙H2O and characterized by IR, PXRD and single crystal X-ray diffraction. The title complexes are from 1D "W"-shaped chains to 6-connected layers based on carboxylates and L ligands mixed linkers. The effect of metal and carboxylate on the structures of the title complexes were investigated. As fluorescent sensors for nitroaniline (NA) and nitrophenol (NOP), the title complexes show good recoverability, low LOD and high sensitivity. The applicability of [Cd(L)0.5(1,4-H2BDC)(H2O)]∙H2O was demonstrated by testing NOP and NA in three different aqueous environments (tap water, river water and wastewater). The corresponding modified detection paper and cloth were prepared and used for the recognition of NOP and NA. [ABSTRACT FROM AUTHOR]

The interaction of nickel(II) with halogenazomercaptophenols (HAMPs) {1-(5-bromo-2-pyridylazo)-2-hydroxy-4-mercaptophenol and 1-(5-iodo-2-pyridylazo)-2-hydroxy-4-mercaptophenol} in the presence of aminophenols (APs) 2,6-bis(N,N-dimethylaminomethyl)-4-methylphenol and 2,6-bis(N,N-dimethylaminomethyl)-4-ethylphenol was studied by the extraction-photometric method. The charge of the resultant complexes was determined by the methods of ion electromigration and electrophoresis on paper. Colored complexes proved to be anions. Upon introduction of the aminophenols into the system the anionic complexes passed into the organic phase in the form of mixed-ligand complexes (MLCs). A single extraction with chloroform provided a 97.1–98.9% yield of nickel(II) in the form of an MLC. The optimal range of acidity of the medium, corresponding to a maximal and constant absorbance, was pHopt 2.4–6.5 (рHform 0.7–8.4). The maximum absorbance was reached within 8–12 min. The optimal condition for the formation and extraction of these compounds were identified as HAMP concentration of (1.12–2.34)×10–3 M and the AP concentration of (6.3–8.4)×10–4 M. A 20-fold increase in the volume ratio of the aqueous to organic phase did not affect the completeness of the extraction. Light absorption was at a maximum at 605–648 nm. In the composition of the MLCs, there was one mole of HAMP and AP each per mole of nickel. Using the Nazarenko method, it was found that Ni2+ is the complexing form of nickel. The number of protons it displaced from one H2L molecule turned out to be equal to 2. The performed calculations showed that the MLCs do not polymerize in the organic phase and occur in the monomeric form (γ = 0.94–1.07). The results of studies on the formation and extraction of MLCs of Ni(II) with HAMP and AP and the physicochemical and analytical characteristics of these compounds served as a basis for the development of new techniques for the extraction-photometric determination of Ni(II) in wastewater, bottom sediments, crude oil, and petroleum products of Baku. [ABSTRACT FROM AUTHOR]

In this paper, 20 compounds containing bis-(1,2,3 and 1,2,4)-triazole structure were synthesized and their antifungal activities against Candida fungi and Aspergillus niger were analyzed in vitro. Some of the prepared compounds exhibited the most promising activity compared with voriconazole and amphotericin B. Molecular docking studies were performed to for additional substantiation of antifungal activity of these derivatives. So, these compounds are expected to provide new ideas for the development of antifungal drugs. [ABSTRACT FROM AUTHOR]

The study of biominerals of a pathogenic nature in organisms is relevant and necessary for establishing the mechanism of their formation and solving many practical issues. Recently, intensive research has been carried out in the field of biochemistry of D-amino acids, it is believed that they can be potential biomarkers of various pathological processes in the human body. The presence of enantiomers of amino acids and their role in the mechanism of formation of gallstones, the issue has not yet been studied. The paper presents data on the distribution of D-enantiomers of amino acids, their content and ratio with L-forms in the composition of gallstones. A comparative analysis of the obtained results on gallstones with urinary stones is shown. It has been established that there is a relationship between the enantiomers of amino acids and the calcium mineral component. [ABSTRACT FROM AUTHOR]

In this paper, a low-content Ce-doped trimetallic sulfide catalyst (Ce–NiFe2S4) was prepared by the hydrothermal method. The prepared catalyst can improve the oxidant potential of peroxymonosulfate (PMS) to degrade rhodamine B (RhB) dye efficiently in a low dosage. In addition, Ce–NiFe2S4 possessed a magnetic property due to the contained nickel-iron elements. Therefore, the catalyst material has good separation and reusability characteristics. The factors influencing the degradation efficiency of rhodamine by a Ce–NiFe2S4-facilitated PMS oxidation system, such as initial solution pH, PMS dosage, catalyst dosage, and temperature were investigated. The results revealed that RhB can be degraded by 95 % in 30 min at the optimal conditions (100 mg/L catalyst, 200 mg/L PMS). The reaction rate would be further increased when the initial solution pH was 3 with the reaction temperature at 50°C. Furthermore, the quenching experiments verified that 1O2 made an important contribution to the degradation of pollutants as a main active species. SO4•– and •OH, to some extent, participated in the chemical degradation reaction. S2– promoted cycling of redox reactions between metal ions and PMS to ensure catalyst stability and reusability. [ABSTRACT FROM AUTHOR]

This paper represents a convenient method for the synthesis of N-[1-(2-acetyl-4,5-dimethoxyphenyl)propan-2-yl]benzamide and its Cu(II) complex. In silico analysis predicted spasmolytic activity for the compound. Based on the in silico calculations, the importance of the predicted ketoamide, and our previous experiments, we synthesized the ketoamide via ortho-acylation of N-[1-(3,4-dimethoxyphenyl)propan-2-yl]benzamide with acetic anhydride in polyphosphoric acid. We applied the title ketoamide in reaction with Cu(II) varying the solvents. We found that the reaction leads to the formation of a coordination compound when the ligand dissolved in DMSO reacts with a water solution of CuCl2 in an alkaline environment in a molar ratio M : L : OH– = 1 : 2 : 2. The structures of the new compounds are discussed based on their melting points, IR, 1H, 13C NMR and Raman spectral data. [ABSTRACT FROM AUTHOR]

A good graphical correlation is observed between the number of nitrogen atoms and pKa for the deprotonation of N(1)–H of azoles (pyrrole to pentazole). Similarly, there is a good correlation between the number of phosphorous atoms and P(1)–H of phospholes (phosphole to pentaphosphole). Using this empirical Katritzky type correlation technique with our DFT data, this paper presents a comparison of the pKa of cyclopentadiene (in which the number of nitrogen or phosphorous atoms is zero), by interpolation of the locus to zero, of the pKa versus number of nitrogen atoms correlation for the azole series and similarly for the pKa versus number of phosphorous atoms correlation for the phosphole series. A value of pKa = 22.5 for cyclopentadiene is obtained from the correlation with the azoles and of 13.5 from the correlation with phospholes. The literature value of pKa for cyclopentadiene, however, is 15. The actual pKa value for cyclopentadiene differs from that predicted by the correlation by 7.5 pKa units for azoles, while it deviates by a much smaller 1.53 pKa units from the value predicted by interpolation from the phospholes. Candidate explanations are considered. [ABSTRACT FROM AUTHOR]

The paper described a superior method for preparing photodegradation catalysts based on a metallic-organic framework (MOFs) template. Cadmium sulfide (CdS) nanoparticles with high photocatalytic activity are a transition metal sulfide semiconductor. Here, the Co2Zn1–MOF bimetallic template was successfully synthesised by solvothermal conditions and then calcined in air to obtain bimetallic oxides. In addition, a new class of bimetal composite photo-catalytic material (ZnS–Co3S4/CdS) was successfully synthesized by sulphiding and compounding with CdS nanoparticles. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible absorption spectroscopy (UV-Vis) analysis. The photocatalytic activities were also studied, and the photo-degradation mechanism of composite is discussed briefly. The results suggest that the bimetal composite material has good morphology and a suitable size. The bimetallic material composited with nano-CdS particles (ZnS–Co3S4/CdS) may be a new type of photocatalytic material to treat organic pollutants in water. This work provides a new approach to synthesizing efficient semiconductor photocatalysts based on MOFs template. [ABSTRACT FROM AUTHOR]

A phosphate flame-retardant hardener (PFH) produced on the basis of industrial orthophosphoric acid and acetic anhydride was proposed for reducing the combustibility and revealing the natural texture of wood. Under fire conditions, phosphorus-containing compounds are able to decompose with formation of polyphosphoric acids providing a barrier coating on the combustion surface, as well as of substances inhibiting free-radical combustion, thereby reducing the rate of combustion and heat release. Wood surface treatment with the PFH was shown to reveal the natural texture of wood as a result of the reactions between the hydrolysis products of cellulose with the lignin components by the mechanism operating in the formation of triphenylmethane dyes. It was demonstrated that specifically the phenolic components of lignin participate in the formation of colored compounds, since cellulose with 90% lignin removed and cotton roving are not colored by the PFH. Softwoods are colored more strongly than hardwoods because of a higher lignin content. A complete scheme of reactions responsible for the appearance of colored structures in the wood texture in the presence of the PFH and atmospheric oxygen was proposed. A mechanism of thermal decomposition of cellulose during combustion in the presence of the PFH, resulting in predominant formation of a carbonaceous residue, was considered. From the quantitative data provided by the experiments on burning Whatman filter papers impregnated with the PFH, catalysis of the coke formation and enhancement of the coke yield were inferred. It was concluded that treatment with the PFH provides decorative appearance to wood and produces a protective effect thereon via reducing combustibility. A system of transparent decorative fire-resistant wood finishing was proposed, in which the PFH performs the function of a flame retardant and Porenbeize, and as well as of a hardener for epoxy varnish finish coating. [ABSTRACT FROM AUTHOR]

In this paper, a new type of ligands has been designed, and two monomeric catalysts have been synthesized by reaction with zinc and cobalt. Reaction of these monomeric catalysts with styrene has led to a series of polymerization-type catalysts. These monomeric and polymerization-type catalysts have been used to catalyze copolymerization of CO2 and propylene oxide. Catalytic efficiency of monomeric cobalt is two times higher than that of monomeric zinc, and polymerization-type catalysts demonstrate higher catalytic activity than monomer catalysts. Due to the synergism of zinc and cobalt, the polymerization-type bimetallic catalyst [ZnCo1 : 1 : 6] is determined to be the most efficient. Copolymerization of ethyl isocyanate and propylene oxide is characterized by the same properties, but the catalytic efficiency is 121 times higher for CO2 and propylene oxide upon using [ZnCo1 : 1 : 6]. According to TGA data, ethyl isocyanate is more active than CO2, the copolymers of ethyl isocyanate/PO and ethyl isocyanate/CO2/PO degrade easier than CO2/PO. [ABSTRACT FROM AUTHOR]

This paper presents a method of synthesis, elucidation of structure and antimicrobial activity of new Cu(II), Pd(II) and Au(III) complexes with 2-thiouracil. Structures of the new compounds are based on UV-Vis, IR, 1H and 13C NMR, and Raman spectral data. Interpretation of complexes spectra is supported by 1H–1H COSY, DEPT-135, HMBC, and HMQC spectra recorded for 2-thiouracil. Antimicrobial activity of the products has been tested against Gram-positive and Gram-negative bacteria and yeasts. [ABSTRACT FROM AUTHOR]

Based on the concept of the proton hydrate-anion complex [H(H2O)n]+A−, equations are proposed that characterize the catalytic activity of the proton in aqueous solutions of three acids: sulfuric, hydrochloric, and chloric. The equations are based on the linear dependence of the value of "excessive acidity" on the logarithm of the relative stoichiometric concentration of water Х = f(log C*w) in acid solutions with a predominance of water (Н2О/НА > 1). Using the directly proportional dependence of the Hammett function (–H0) on the sum of parameters (log C*H+ + mX), two-parameter equations were obtained for calculating the complex function of acidity –Hw0 = log C*H+ + Blog C*w (standard state—pure water, C0w). The equations make it possible to calculate the function Hw0 at a given acid concentration, having only data on the concentrations of the proton CH+ and water Hw0, i.e. avoiding the use of the ratio of the activity coefficients of the components included in parameter X. The function Hw0 collectively reflects the participation of proton and water in the acidity of the medium, practically reproduces the experimental values of H0 obtained by different authors in the concentration range from pure water to 68 wt % (H2SO4), 40% (HCl), 70% (HClO4), combines the pH and H0 scales. It is concluded that the Blog Hw0 contribution, which characterizes the participation of water in the hydration shells of ions, is determined by their nature and plays no less important role in characterizing the acidity of the medium than the proton itself. The final tables of the concentration dependence of the values Hw0 for each of the acids are given. The paper represents a methodological review, since it is based on a critical analysis of experimental literature data. [ABSTRACT FROM AUTHOR]

Numerous electrochemical and chemical methods are suitable for preparation of tungsten trioxide (WO3) films. Many of these methods, however, have not been carefully studied, so information on the specific features of the WO3 film deposition technology is lacking. This paper describes the preparation of WO3 films by cathodic electrodeposition from the synthesized solution of peroxotungstic acid (PTA) on the surface of thermally expanded graphite (TEG) and titanium electrodes designed as foils. A stepwise pattern of reduction of tungsten oxides from PTA was revealed. The suitability of the WO3 film electrode as a material for electrochemical power industry was experimentally demonstrated. Specifically, WO3/Ti was found to be applicable as a protective coating for hydrogen fuel cells, and WO3/TEG, as a cathode material for asymmetric supercapacitors. Based on the charge-discharge curves for the WO3/TEG electrode used as a cathode in the free volume of th KOH electrolyte, the specific capacitance of the supercapacitor was estimated at 630 F/g. Electrochemical analysis showed that that WO3 films deposited on the titanium surface afford enhancement of the hydrogen overpotential and protection against pitting corrosion during potentiostatic polarization tests at the cathode potential of a fuel cell. [ABSTRACT FROM AUTHOR]

The paper presents the results of mixing and dispersing binary mixtures of EVA (ethylene vinyl acetate copolymer) and mixtures with polyethylene, carried out using the anti-solvent method (SEDS). The melting and crystallization kinetics in polymer blends obtained by mixing in a melt and using the SEDS method have been investigated. It was found by X-ray diffraction and differential scanning calorimetry (DSC) methods that the crystallization of polymer blends by the SEDS method leads to an increase in the degree of crystallinity. The results of the study of the physical and mechanical characteristics of the mixtures under study are presented. [ABSTRACT FROM AUTHOR]

Up-to-date data on the concentrations of priority PAHs in the sediments of Lake Baikal in 2019–2020 have been obtained by HPLC with fluorometric detection. The results of the monitoring of PAHs in the sediments in the areas subject to anthropogenic impact, including discharges of municipal sewage effluents from the city of Baikalsk [wastewater discharges of the former Baikal Pulp and Paper Mill (BPPM)], landfills of the front delta of the Selenga River, and the northern part of the lake adjacent to the Baikal–Amur Mainline (BAM), are presented. The concentration of 15 PAHs in the BPPM region varied from 8.5 to 737.8 ng/g, in the Selenga region, from 23.6 to 218.9 ng/g, and in the BAM region, from 2.2 to 380.8 ng/g. Analysis of the sediment samples from the region of the Small Sea of Baikal was performed for the first time (total PAHs 3.2–121.3 ng/g). The minimum PAH concentrations were found in low organic matter consertal sands. The average concentration of benzo(a)pyrene, as well as other high-molecular-weight PAHs, was approximately 2–5 times higher in the sediments of the Baikalsk region compared to the BAM region and the front delta of the Selenga River. It was found that the PAH profiles in the sediments of the BAM and Selenga landfills were similar to each other and significantly differed from those of the Baikalsk landfill. The study of the origin of PAHs in the sediments showed that most of the samples were of pyrogenic nature. The pyrogenicity indices (∑ PAHs (4-6-nuclear)/total PAHs and ∑ PAHs (5-6-nuclear)/ ∑ PAHs (2–4-nuclear) were higher in the southern Baikal region compared to the delta of the Selenga River, Small Sea, and nothern Baikal. [ABSTRACT FROM AUTHOR]

The paper studies the possibility of changing the properties of piezoceramic materials of various functional groups. The aim of this work was to vary the properties of piezoceramics at the stage of production by changing the technological factors with a constant chemical composition. The microstructure of piezoceramics is formed during its sintering, and also are the most important mechanical properties – density and hardness – which affect electrophysical properties. Therefore, by correcting the microstructure formation process, it is possible to change the electrophysical properties of piezoceramics. Methods of hot pressing and spark plasma sintering allow us to effectively correct the forming process of the sintered piezoceramics microstructure. The aim of this study was to use these methods for the sintering of piezoceramic materials of various functional groups and variations of their parameters. The study confirmed the effectiveness of the proposed methods for a wide-range changing piezoceramic functional parameters. [ABSTRACT FROM AUTHOR]