Гибридный металлополимер как потенциальная активная среда оптоакустического генератора

A hybrid material was studied, consisting of polydimethylsiloxane and silver nanoparticles distributed throughout its volume, its optical and thermodynamic characteristics were calculated for different volume fractions of silver content. It is theoretically shown that this material with a volume fraction of silver of about 30% can be used as an active medium for an optoacoustic transducer with an operating frequency range of about 10 MHz.

Synthesis of Higher Alcohols on Silver-promoted LaCo- and LaCoCu-Perovskites

LaCoO3 and LaCo0.7Cu0.3O3 perovskites supported on highly dispersed mesoporous silica KIT‑6 were impregnated with silver nitrate (nAg/nCo = 4/99 and 8/99). The phase composition of the initial samples and samples after catalytic tests in syngas conversion and catalytic characteristics have been investigated. The regularities of the transformation of samples in the process of reduction in a hydrogen-containing gas have been studied. It is shown that, for the LaCoO3 sample, with an increase in the silver content, the activity and selectivity for higher alcohols increase from 6 to 23 %. The maximum interaction of cobalt with silver is observed at a silver content of 4 %. At a higher content, part of the cobalt is reduced regardless of the influence of silver due to its faster agglomeration. This leads to a stronger amorphization of the reduced sample and a sharp increase in its activity. The LaCo0.7Cu0.3O3 sample exhibits a higher selectivity for higher alcohols (36 %) due to the effect of copper. Silver promotion of the sample allows achieving the maximum selectivity for higher alcohols of 56 % with a silver content of 4 %. A further increase in the silver content leads to a sharp decrease in the selectivity for higher alcohols (41 %) and the appearance of CO2 due to the saturation of copper-containing particles with silver and a decrease in the interaction of cobalt with copper

Influence of preparation of silver nanoparticles in carriers based on polymer/inorganic hybrids on the mineral composition of chicken eggs

The solution to the problem of reducing the use of antibiotics in the production of edible eggs is possible through the development and use of alternative bactericidal preparations, including those based on nanosilver. Obtaining biocompatible and biodegradable polymer/inorganic carriers of nanosilver provides for the study of its cumulative qualities which determine the safety of edible chicken eggs. The study investigated the mineral composition of edible eggs when feeding Hy-Line W36 laying hens solutions of the nanosilver preparation in carriers based on polymer/inorganic hybrids (AgNPs/SPH) given in the concentrations of 0, 1.0, and 2.0 mg/L of water (0, 0.2 and 0.4 mg/hen per day) three times at 10 day intervals. Oral administration to laying hens of an aqueous solution of silver nanoparticles in carriers based on polymer/inorganic hybrids at doses of 0.2 and 0.4 mg per hen per day in a dose-dependent manner increased the silver content and did not significantly affect the content of copper, zinc, iron, and lead in the eggshell. The preparation of silver nanoparticles did not affect the content of silver, copper, zinc, iron and lead in the albumen and yolk of chicken eggs after the first and second application, and after the third treatment of laying hens contributed to an increase in the silver content in the egg albumen and yolk but did not affect the content in them of copper, zinc, iron and lead. A single feeding of a solution of a preparation of nanosilver in carriers based on polymer/inorganic hybrids to hens at doses of 0.2 and 0.4 mg per hen per day after 10 days, contributed to a significant increase in the yolks of chicken eggs due to a decrease in the albumen and eggshell. The second and third application of nanosilver to poultry in the indicated doses contributed to a decrease in its proportion in the albumen and in the yolk due to a significant increase in its proportion in the shell. Selective accumulation of in-shell silver can be a promising means of improving the safety and security of chicken eggs when they are microbially contaminated. The results of using nanosilver based on polymer/inorganic hybrids in laying hens can be the basis for the development of methods for increasing the bactericidal properties of the shell and the safety of edible eggs.

The Poly(Chloro-P-Xylylene)-Ag Metal-Polymer Nanocomposites Obtained by Controlled Vapor-Phase Synthesis for SERS Effect Realisation

Substrates based on the metal-polymer nanocomposites 2,3-dichloro-p-xylylene-silver (PCPX-Ag) that realize the effect of surface-enhanced Raman scattering (SERS) were developed. To obtain nanocomposites, the vapor-phase polymerization method was used (VDP), which makes it possible to control the nanocomposite microstructure. In the process of self-assembly during VDP, nanocomposite films with inclusions of silver particles were formed on the polycore substrates. Silver content varied from 2.5 to 16% vol. The possibility of using such substrates for the detection of low-molecular substances, for example 5,5′-dithiobis- (2-nitrobenzoic acid) (DTNB) analyte, by the SERS method with an enhancement factor of up to 104, was demonstrated. The dependence of the SERS spectra enhancement on the microstructure of the nanocomposite and the silver content was determined. The optical and morphological properties of nanocomposites were also investigated and their dependence on the silver content was shown. It has been demonstrated that the nanocomposite is SERS selective since when working with complex solutions in the presence of high molecular weight substances, signal enhancement was only observed for low molecular weight substances.

Effect of Silver Modification on the Photoactivity of Titania Coatings with Different Pore Structures

Nanostructured photoactive systems are promising for applications such as air and water purification, including self-cleaning coatings. In this study, mesoporous TiO2 sol-gel coatings with different pore structures were prepared and modified with silver by two methods: the “mixing” method by adding AgNO3 to the precursor sol, and the “impregnation” method by immersing the samples in AgNO3 solution (0.03 and 1 M) followed by heat treatment. Our aim was to investigate the effects that silver modification has on the functional properties (e.g., those that are important for self-cleaning coatings). Transmittance, band gap energy, refractive index, porosity and thickness values were determined from UV-Vis spectroscopy measurements. Silver content and structure of the silver modified samples were characterized by X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, High-resolution transmission electron microscopy and Energy Dispersive X-ray Spectrometry elemental mapping measurements. Wettability properties, including photoinduced wettability conversion behavior were investigated by water contact angle measurements. Photoactivity was studied under both UV and visible light with rhodamine 6G and methylene blue dye molecules, at the liquid–solid and air–solid interfaces modeling the operating conditions of self-cleaning coatings. Samples made with “impregnation” method showed better functional properties, in spite of their significantly lower silver content. The pore structure influenced the Ag content achieved by the “impregnation” method, and consequently affected their photoactivity.

Effect of enhanced recovery after surgery management combined with nano-antibacterial dressing during perioperative nursing practice on rehabilitation of patients with gynecological tumor

The nano-silver antibacterial dressing is processed and formed after being expanded and cut by medical degreased gauze and nano-silver solution. The nano-silver content is 0.4%–1.0% of the dressing mass (the nano-silver content per square meter of the dressing is 0.28–0.7 g). Nano silver plays an auxiliary role in reducing wound infections. This study is the first to report the rehabilitative effect of enhanced recovery after surgery (ERAS) management combined with nano antibacterial dressing in the perioperative period of gynecological cancer. The times until first exhaust, first defecation, ambulation, and the duration of hospitalization of the ERAS group were shorter than in the regular group. The VAS scores at 6 and 12 h after operation in the ERAS group were lower than those in the regular group. The levels of self-responsibility, self-concept, self-care skills, and health knowledge in the ERAS group were higher than those in the regular group. The total incidence of complications in the ERAS group was 9.09%, which was lower than that in the regular group (23.64%). The level of satisfaction with nursing care in the ERAS group was 98.18%, which was higher than that in the regular group (83.64%). The findings confirmed that ERAS combined with nano antibacterial dressing can promote the rehabilitation of patients, relieve pain, strengthen the self-care ability of patients, reduce the occurrence of complications, and improve satisfaction with nursing care.

Structure–Activity Relationships between the State of Silver on Different Supports and their I2 and CH3I Adsorption Properties

In this study, the performances of silver-impregnated adsorbents prepared from different host supports (SBA-15, alumina, ceria, and faujasite Y zeolite) and calcined or not at 500 °C (1 h) were compared for the capture of I2 and CH3I. By keeping the silver content rather similar (about 15–17 wt %) among the sorbents, it was possible to assess the effect of silver dispersion and speciation on the adsorption capacities measured for both adsorbates. In a first part, several characterization techniques (XRD, DRS-UV-Vis, TEM, etc.) were used to probe the state of silver in the calcined and non-calcined materials. It was found that the characteristics of silver species are strongly influenced by the thermal treatment, the presence or absence of exchange sites, and the stability of the supports. Silver agglomeration was enhanced after calcination at 500 °C especially for supports bearing no exchange sites (SBA-15) or no ordered pores (alumina and ceria). Then, the adsorption performances of the studied silver sorbents were discussed in relation with their physicochemical characteristics. After-test characterizations were useful to assess the proportion of silver species that have reacted with CH3I and I2 to yield AgI precipitates. Depending on the adsorbate, different trends were obtained. I2 adsorption/reaction with silver sites was found to be quantitative (I/Ag ≈1), whatever the silver speciation and dispersion on the support. By contrast, a high proportion of cationic silver species was found essential to increase CH3I adsorption (I/Ag about 0.6–0.7 against 0.2–0.3 for Ag agglomerated species).

Development of the processing technology for porphyry copper ores of the Tominsky deposit

The article presents the results of the studies for the porphyry copper ores of the Tominsky deposit conducted to develop the respective processing technology. These process studies had been carried out since 2011 jointly by the TOMS Institute, Outotec, and JSC Mekhanobr Engineering. The experiments were carried out in 2017 at the laboratory of Mekhanobr Engineering using an ore charge from the Tominsky deposit and its Kalinovsky area with the percentage ratio of 75:25, copper content of 0.37 wt%, gold content of 0.09 g/t, and silver content of 0.89 g/t. The closed-cycle experiments yielded copper concentrates containing 20.7 wt% of copper, 3.95 g/t of gold, and 39.9 g/t of silver, with the recoveries of 90.27, 72.71 and 72.45 %, respectively. According to the results of the studies, the following technology was recommended for the design of the concentrator for the ores of the Tominsky deposit: semi-autogenous grinding and ball milling of the ore to 85 % passing –0.071 mm, rougher and scavenger flotation, rougher concentrate regrinding to 80 % passing –0.035 mm and two cleaner flotation stages for the rougher concentrate to obtain grade KM-5 copper concentrate with the mass fraction of copper of 20 % and copper recovery of 85 %. The concentrator of JSC Tominsky GOK, designed by JSC Mekhanobr Engineering, was put into pilot operation in 2020 and has reached its design performance.