卷 489, 编号 1 (2019)
- 年: 2019
- 文章: 6
- URL: https://journals.rcsi.science/0012-5008/issue/view/9329
Chemistry
Mono- and Di(dechloromethylthioylation) of Dichloromethylarenes with S-Methyl Diethylthiophosphinate
摘要
The attack of the thiol sulfur atom (P–SMe) on the methine carbon as the main route of the new reaction of dichloromethylarenes with S-methyl diethylthiophosphinate has been predicted and experimentally confirmed on the basis of the electronic structure of the S-alkyl esters of P(IV) acids. The processes of the mono- and di(dechloromethylthioylation) of dichloromethyl group have been realized. A new approach to the synthesis of the arenecarbaldehyde dimethyl dithioacetals has been developed avoiding the use of gaseous highly toxic methyl mercaptan.
Development of a Biocompatible and Biodegradable Polymer Capable of Long-Term Release of Biologically Active Substances for Medicine and Agriculture
摘要
A process was developed for producing biocompatible and biodegradable polymer films based on high-molecular-weight polylactide with properties necessary for medical and agricultural applications. A method was devised for the inclusion of active substances (gentamicin sulfate, lincomycin hydrochloride, or cefotaxime) into high-molecular-weight polylactide films. The rate of release of active substances from polylactide can vary with time according to a decaying exponential law or nearly linearly. The release of active substances is significantly affected by pH of the solution surrounding the film. It was found that the dynamics of release of active substances from biocompatible biodegradable polymer films based on high-molecular-weight polylactide depends on the properties of the immobilized substance, the film preparation method, and the conditions of extraction. The biocompatible biodegradable polymer films based on high-molecular-weight polylactide are quite suitable for the manufacture of coatings for stents and prostheses with prolonged and controlled drug release into the surrounding tissues and for agricultural applications to improve crop preservation.
Copper-Containing Nanosystems Based on Macromolecular Hydrophilic Stabilizers
摘要
An original method for the synthesis of copper-containing nanosystems for biomedical applications using hydrazine hydrate as a reducing agent was developed. The process involves intermediate formation of the [Cu(NH3)4]2+ complex ion, which ensures the formation of Cu0 nanoparticles without oxide impurity. The 2-deoxy-2-methacrylamido-D-glucose copolymer with 2-(dimethylamino)ethyl methacrylate or bovine serum albumin was used as a macromolecular hydrophilic stabilizer. The spectral and structure-morphological characteristics of the nanosystems were studied. This stabilization resulted in an almost unimodal distribution of zerovalent copper nanoparticles in aqueous solutions due to their rather good shielding by macromolecules.
Chemical Technology
Production of a Composite Based on Alumina Nanofibers and Detonation Nanodiamonds for Creating Phenol Indication Systems
摘要
A composite of alumina nanofibers (ANF) and modified detonation nanodiamonds (MDND) was produced by mixing aqueous suspensions of the components in a weight ratio of 5 : 1 with subsequent incubation of the mixture for 15 min at 32°C. It was assumed that the formation of the composite is ensured by the difference of the zeta potentials of the components, which is negative for MDND and positive for ANF. Vacuum filtration of the mixture through a fluoroplastic filter (pore diameter 0.6 μm) formed disks 40 mm in diameter, which were then heat-treated at 300°C to impart structural stability to the composite. Scanning electron microscopy detected that the obtained composite has a network structure, in which MDND particles are distributed over the surface of ANF. It was determined that the MDND particles incorporated in the composite catalyze the phenol–4-aminoantipyrine–H2O2 oxidative azo coupling reaction to form a colored product (quinoneimine). The applicability of the composite to repeated phenol detection in aqueous samples was demonstrated.
Effect of Doping with Sodium and Potassium on the Phase Formation in the Synthesis of Calcium Sulfate
摘要
Materials based on calcium sulfate in which Na+ or K+ cations were substituted to a concentration of 5, 10, or 20 mol % for Ca2+ cations were synthesized and studied. The introduction of Na+ produced materials with the structure of calcium sulfate hemihydrate and dihydrate, and the incorporation of potassium yielded a mixture of calcium sulfates with various contents of chemically bound water and sulfates in which potassium cations formed compounds with different Ca : K ratios. The doping of calcium sulfate with sodium and potassium cations increased the solubility of materials by a factor of 1‒2 and 3‒4, respectively. The developed materials are promising in medical applications for filling bone tissue defects and also for using as a cement matrix for targeted drug delivery.
The Effect of Rapid Photon Treatment of the PdCu Solid Solution Foil of Near-Equiatomic Composition
摘要
β \( \rightleftarrows \) α transformations in a thin ~4 µm foil of the PdCu solid solution have been studied by X-ray powder diffraction and measurement of electrical resistance in heating–cooling cycles during heat treatment or rapid photon treatment by radiation of high-power pulsed xenon lamps. It has been found that a single rapid photon treatment for 0.3 s (the radiation energy dose delivered to the sample is 10 J cm–2) leads to a complete disordering of the solid solution at a rate 400 times higher than in that achieved under heat treatment conditions (heating rate of 15 K min–1).