Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)-a component of biofuel. In this work, we developed Ru nanoparticle ...containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H
) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.
A polynomial filtering algorithm has been implemented to identify the central frequency and correlation interval of a narrowband process. The efficiency of the polynomial filtering algorithm is ...carried out by comparing it with the potential accuracy calculated using the algorithm based on multi-alternative filtering. Recurrent relations are proposed for determining the lower bound of accuracy for estimating the parameters of a narrowband process. The possibility of using less computationally expensive procedures for calculating the lower bound of accuracy is investigated.
Introduction. The review article discusses the issues of modern logistics in the production of forensic medical examinations from the infectious safety of personnel point of view. Forensic medical ...examination institutions are special types of health care institutions. Special requirements are imposed on the design of buildings and the logistics of such institutions. Aim. The purpose of the study is to analyze scientific information on the planning decisions of buildings for forensic purposes and the material and technical equipment of the forensic medical examination in terms of infectious safety of personnel. Material and methods. When preparing a literature review, the literature search method was used in the PubMed, eLibrary.ru, Google Scholar databases for the period 2005–2021. The analysis included literature reviews, meta-analyses, and clinical studies. Results and discussion. The studies present organizational and technological solutions for the design of buildings and the logistics of institutions of forensic medical examination. Attention is drawn to compliance with sanitary standards and requirements for premises, equipment in accordance with standards in order to create safe working conditions for forensic doctors, which ultimately allows to significantly improve the quality of forensic medical examination. Conclusion. Researchers have recognized that at present, the infectious safety of employees of forensic institutions is very important. The Bureau of Forensic Medical Examination and pathology departments need to be improved. This improvement should be based on modern building design and sanitary and hygienic logistical support, so building and improving the logistical capacity of these institutions is necessary and remains a major challenge to be addressed.
Heat-up and hot-injection methods were employed to synthesize Ni nanoparticles (NPs) with narrow size distribution in the presence of hyperbranched pyridylphenylene polymer (PPP) as a stabilizing ...agent. It was shown that depending on the synthetic method, Ni NPs were formed either in a cross-linked polymer network or stabilized by a soluble hyperbranched polymer. Ni NPs were characterized by a combination of transmission electron microscopy (TEM), scanning TEM, thermogravimetric analysis, powder X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray analysis, and magnetic measurements. The architecture of polymer support was found to significantly effect Ni NPs characteristics and behavior. The Ni NPs demonstrated a high catalytic activity in a model Suzuki-Miyaura cross-coupling reaction. No significant drop in activity was observed upon repeated use after magnetic separation in five consecutive catalytic cycles. We believe that hyperbranched PPP can serve as universal platform for the controllable synthesis of Ni NPs, acting as highly active and stable catalysts.
The synthesis of bacterial cellulose (BC) by
strain B-12068 was investigated on various C-substrates, under submerged conditions with stirring and in static surface cultures. We implemented the ...synthesis of BC on glycerol, glucose, beet molasses, sprat oil, and a mixture of glucose with sunflower oil. The most productive process was obtained during the production of inoculum in submerged culture and subsequent growth of large BC films (up to 0.2 m
and more) in a static surface culture. The highest productivity of the BC synthesis process was obtained with the growth of bacteria on molasses and glycerol, 1.20 and 1.45 g/L per day, respectively. We obtained BC composites with silver nanoparticles (BC/AgNPs) and antibacterial drugs (chlorhexidine, baneocin, cefotaxime, and doripenem), and investigated the structure, physicochemical, and mechanical properties of composites. The disc-diffusion method showed pronounced antibacterial activity of BC composites against E. coli ATCC 25922 and S. aureus ATCC 25923.
Unmanned network robotics is a new multidisciplinary field that involves many fields of computer networks, multi-agent systems, control theory, 5G and 6G Internet, computer security, and wireless ...quantum communications. Efficient conjugation of such technologies needs to design new data verification schemes for robotic agents using the advantages of quantum key distribution lines. For such schemes the joint use of known fuzzy logic parametrical -gates and discrete multiple-valued logic models simplifies the application of quantum quasi-random keys. Namely, the separate regulating parameter in -gates is the most convenient tool to use quantum keys in comparatively simple classical control and verification procedures that do not involve quantum logic gates.
The fully consolidated bilayer (consisting of two amorphous Al86Ni9Gd5 melt-spun ribbons) disks with a diameter of 5 mm were produced using unconstrained high pressure torsion (HPT) processing ...subjecting for 2–5 turns at applied pressures of 2 and 4 GPa. The structure and mechanical properties of the disks as well as those of the as-prepared and heated up to 479 K ribbon samples were studied by X-ray diffraction analysis, transmission and scanning electron microscopy, three-point bending tests and measurements of microhardness. It was established that the heat treatment and consolidation resulted in formation of nanocomposite structures consisting of Al nanocrystals 21 and 6 nm in size, respectively, with enhanced microhardness. It was shown that the heat treatment of the ribbon led to a loss of the plastic strain (from 2 to 0.4%) while the consolidated disks retained the same level of plasticity as that in the as-cast amorphous ribbon. The possible reason of the enhanced plasticity of the nanophase composites obtained by deformation-induced crystallization was discussed.
The present study describes production of bacterial cellulose composites with silver nanoparticles and antibiotics and compares their properties. Bacterial cellulose (BC) composites synthesized in ...the culture of the strain of acetic acid bacterium Komagataeibacter xylinus VKPM B-12068 with silver nanoparticles, BC/AgNps, were produced hydrothermally, under different AgNO3 concentrations (0.0001, 0.001, and 0.01 M) in the reaction medium. The presence of silver in the BC/AgNp composites was confirmed by elemental analysis conducted using scanning electron microscopy with a system of X-ray spectral analysis. Analysis showed that the average atomic number of silver particles in composite samples depended on the concentration of AgNO3: as AgNO3 concentration in the reaction solution was increased, silver content in the composites increased from 0.044 to 0.37 mg/cm2. BC composites with amikacin and ceftriaxone were prepared by immersing dry BC films in solutions containing different concentrations of the antibiotics. The surface structure and properties and physicochemical and mechanical characteristics of composites were investigated using SEM, DSC, X-ray analysis, the system for measuring water contact angles, and electromechanical tensile testing machine. The disk-diffusion method and the shake-flask culture method used in this study showed that all experimental composites had pronounced antibacterial activity against E. coli, Ps. eruginosa, K. pneumoniae, and St. aureus, and the BC/antibiotic composites were more active than BC/AgNp ones; S. aureus was the most susceptible to the effect of BC composites. No potential cytotoxicity was detected in any of the BC/AgNp composites in the NIH 3T3 mouse fibroblast cell culture, in contrast to the BC/antibiotic composites. These results suggest that BC composites constructed in the present study hold promise as dressings for managing wounds, including contaminated ones.
•Production of BC composites with AgNps, antibiotics and their properties was studied.•The presence of silver in the BC/AgNp composites was confirmed by elemental analysis.•Physicochemical and mechanical characteristics of composites were investigated.•All experimental composites had pronounced antibacterial activity.•BC composites were investigated in fibroblast cell culture.
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