Synthesis,antioxidant activity,and α-glucosidase enzyme inhibition of α-aminophosphonate derivatives bearing piperazine-1,2,3-triazole moiety

A novel series of piperazine-1,2,3-triazole bearing dimethyl(((2-(4-((1H-1,2,3-triazole-4-yl)methyl)piperazin-1-yl)ethylamino)(2-hydroxyaryl)methyl)phosphonate derivatives have been prepared via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) (Click Reaction) and Schiff base reactions. The synthesized compounds were confirmed by spectral characterization (¹H, ¹³C and ³¹P NMR, and mass). The title compounds were evaluated for in vitro alpha glucosidase enzyme inhibition and in vitro antioxidant activity using DPPH and H₂O₂ methods.     

基于正电荷和光热协同效应的新型半导体聚合物纳米抗菌材料

由于抗生素的不当使用和细菌多药耐药的出现, 迫切需要开发新的抗菌剂. 本文制备了具有光热转换性能的正电荷半导体高分子材料及具有协同抗菌活性的半导体聚合物纳米粒子(SP-PPh₃ NPs). SP-PPh₃ NPs的光热转化效率为43.8%. 带正电荷的SP-PPh₃ NPs可以附着在细菌上, 有助于将热量有效传递给细菌. 在热和正电荷的协同作用下, SP-PPh₃ NPs对革兰氏阴性大肠杆菌(E. coli)和革兰氏阳性金黄色葡萄球菌(S. aureus)均具有抗菌活性, 其对二者的体外抑菌率分别为99.9%和98.6%. 此外, SP-PPh₃ NPs具有良好的生物相容性, 对小鼠的主要器官几乎无副作用. 对细菌感染的小鼠皮肤伤口用SP-PPh₃ NPs治疗12 d后, 伤口可以很好地愈合.     

Diffusion of iodine in lead telluride

By using the non-stationary thermal-probe method, investigations were carrieed out on the distribution of the coefficient of thermal electromotive force along the depth of monocrystals of lead telluride, subjected to isothermal saturating annealing in vapours of alloying compositions. The alloying composition consisted of powdered lead telluride, synthesized by the iodide method, and contained elevated concentration of the metallic component and iodine. The PbTe monocrystals were obtained from the vapour phase and had a natural cut. The results of the investigations testify to considerable changes in the concentration of the electrically active proper defects within the entire volume of the crystals, this being obviously connected with diffusion of vacancies from the crystal volume.     

Etch-pit study of dislocation microstructure at the precipitates in NaCl:Ni crystals

The chemical etching technique was used to study the precipitation-induced dislocation microstructures in NaCl:Ni crystals with 110 rod-like precipitates. The comparison was made of the results obtained by the etch pit and decoration studies. The coincidence of the patterns suggests the prismatic dislocation loops and helices of the interstitial type to be only produced at elevated temperatures (above 300°C). The smallest size loops are removed by climb on slow cooling. These loops sometimes persist in quenched crystals.     

The effect of divalent impurity state on the microhardness of NaCl crystals

The microhardness and bulk density variations with annealing temperature have been measured in NaCl crystals doped with Ca²⁺, Cd²⁺, Ni²⁺, and Pb²⁺. Both characteristics are not affected by coherent metastable precipitation while incoherent precipitation produces either hardening or softening depending on the impurity phase type (stable or metastable). The results support the suggestion that aggregates and coherent precipitates are cut through by dislocations whereas incoherent precipitates are by-passed via the Orowan looping mechanism.     

Precipitation-induced Dislocations in Crystals of NaCl:Ni

Using the decoration technique, the dislocation structure has been observed in regions localized near precipitates in nickel-doped NaCl crystals. The results are interpreted in terms of the stress-operated mechanism for the generation of prismatic dislocations by the precipitates. Normally only two of twelve possible slip directions operate for 〈110〉 rods. This is accounted for in terms of the climb and disappearance of dislocation loops corresponding to the other directions. {100} plates produce loops spreading along for 〈110〉 directions.     

Role of the cure kinetics in morphology control at phase separation of curing multicomponent thermosets and a criterion of equilibrium

The formation of heterophase polymers via phase separation in the course of curing reaction in a blend of a thermosetting oligomer with a rubber modifier is considered. The interference of thermodynamic and kinetic factors that define the morphology of the material being formed is discussed. The need for a kinetic theory of cure-induced phase separation is established, and an approach of this kind is proposed. On the basis of this approach a simple quantitative criterion of deflection of the phase-separating system from the thermodynamic equilibrium is given.     

Modernization of the Thl-100 Laser System to Produce Powerful Terahertz Radiation

Russian Physics Journal - This paper presents the results of research on parameters of the THL-100 hybrid laser system of the visible spectrum with a view to modernizing it, in order to achieve the...     

Bulk non-radiative recombination reduction in nGaAs due to an annealing under Ga-Al melt

It is shown by microcathodoluminescence and electron beam induced current investigations that efficiency of radiative recombination and the values of hole diffusion lengths in nGaAs substrate increase (up to L_p ∽ 5 μm) due to an annealing under Ga Al melt. The values of the annealing critical temperature exceeding of which leeds to bulk non-radiative recombination drop as well as optimal values of annealing temperature and duration are determined. In pAlGaAs–(p-n)GaAs solar cells based on annealed substrates the values of open circuit voltage U_oc = 1.16 – 1.18 V under 500-fold concentrated solar radiation as well as values of photocurrent comparable with the best results of solar cells with epitaxial nGaAs are achieved.