Photocatalytic formulations for protein fibers: experimental analysis of the effect of preparation on compatibility and photocatalytic activities

In this article, we report an optimization study of a photocatalytic self-cleaning sol–gel formulation. In particular we studied the effect of formulation preparation time on the formation of anatase titanium dioxide sol and its compatibility to protein keratin-type wool fibers. The sols were formed by a low temperature sol–gel process. The nucleated anatase was characterized by UV–vis transmission, particle size distribution, X-ray diffraction, and transmission electron microscopy. The compatibility between the formulations and wool fibers is evaluated by field-emission scanning electron microscopy, UV transmission, and mechanical properties. The photocatalytic self-cleaning activity of coated fibers and its reproducibility are also discussed.     

Synthesis,crystal structure and dielectric properties of C6H18N2SbCl5

The result of the X‐ray diffraction, differential scanning calorimetry and dielectric studies on a new crystal material C₆H₁₈N₂SbCl₅ is presented. The new organic–inorganic compound has been synthesized and characterized by the X‐ray diffraction method at 296(2) K. It crystallizes in the monoclinic P21/n space group. The cell dimensions are: a = 5.8617(1) Å, b = 15.7069(2) Å, c = 16.6693(2) Å, β = 97.627(1)° and Z = 4. The crystal structure consists of a discrete ionic layer of (C₆H₁₈N₂)²⁺ cations and [SbCl₅]^2? anions linked via simple and bifurcated N―H · · · Cl hydrogen bonds. DSC analysis shows that this compound undergoes a phase transition at about (384 ± 2) K. AC and DC conductivities, complex dielectric permittivity ε*(ω) and complex electrical modulus M*(ω) were respectively studied as temperature and frequency functions. The combined data support each other and confirm the existence of a structural phase transition at about 384 K. Moreover, the temperature dependence of the DC conductivity and relaxation frequency followed the Arrhenius relation. The frequency dependence of the real part of the AC conductivity in both phases follows the Jonscher's universal dynamic law: . The behavior of s(T) with temperature suggests that the hopping over barrier model (CBH) and the small polaron tunneling mechanism (SPTM) prevail in phases I and II, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

石化装置工业尺度管道爆轰传播实验研究

针对石化装置罐区大口径、长距离管道内火焰传播缺乏系统研究的问题,设计搭建了DN50～DN500工业尺度管道火焰传播实验装置,并开展了丙烷/空气、乙烯/空气等可燃气体在不同管径下的实验研究。实验结果表明:可燃气体积分数对火焰传播及爆轰有一定影响,当接近化学计量浓度时,爆轰加速距离更短,更易形成稳态爆轰,而当可燃气混合气为贫燃或富燃状况时,爆轰加速距离则会增长;火焰爆轰传播速度、爆轰压力与管道管径基本无关,受可燃气种类影响更大;对应体积分数为6.6%的乙烯/空气和体积分数为4.2%的丙烷/空气混合气体,爆轰压力分别是初始压力的15.17和14.47倍,DN150以下管径内的爆轰压力远高于ISO16852标准给出的参考值。罐区连通管道阻火器选型安装时,应结合安装位置选用合适的阻火器。     

Efficient Synthesis of 2-Aminopyridine Derivatives: Antibacterial Activity Assessment and Molecular Docking Studies

A new and suitable multicomponent one-pot reaction was developed for the synthesis of 2-amino-3-cyanopyridine derivatives. Background: This synthesis was demonstrated by the efficient and easy access to a variety of substituted 2-aminopyridines using enaminones as key precursors under solvent-free conditions. Methods: A range of spectroscopic techniques was used to determine and confirm the chemical structures (FTIR, ¹H NMR, ¹³C NMR). The antimicrobial potency of synthesized compounds (2a–d) was tested using disk diffusion assays, and the Minimum Inhibitory Concentration (MIC) for the active compounds was determined against a panel of microorganisms, including Gram-positive and Gram-negative bacteria and yeasts. Moreover, a docking analysis was conducted by Molecular Operating Environment (MOE) software to provide supplementary information about the potential, as well as an ADME-T prediction to describe the pharmacokinetic properties of the best compound and its toxicity. Results: The results of the antimicrobial activity indicated that compound 2c showed the highest activity against Gram-positive bacteria, particularly S. aureus and B. subtilis whose MIC values were 0.039 ± 0.000 µg·mL⁻¹. The results of the theoretical study of compound 2c were in line with the experimental data and exhibited excellent antibacterial potential. Conclusions: On the basis of the obtained results, compound 2c can be used as an antibacterial agent model with high antibacterial potency.     

Clay-Catalyzed Ozonation of Hydrotalcite-Extracted Lactic Acid Potential Application for Preventing Milk Fermentation Inhibition

An unprecedented route for mitigating the inhibitory effect of lactic acid (LA) on milk fermentation was achieved through lactate adsorption on hydrotalcite (Ht) from simulated lactate extracts. During its regeneration by ozonation, Ht displayed catalytic activity that appeared to increase by addition of montmorillonite (Mt). Changes in the pH, Zeta potential and catalyst particle size during LA ozonation were found to strongly influence LA–LA, LA–catalyst and catalyst–catalyst interactions. The latter determine lactate protonation–deprotonation and clay dispersion in aqueous media. The activity of Mt appears to involve hydrophobic adsorption of non-dissociated LA molecules on silica-rich areas at low pH, and Lewis acid–base and electrostatic interactions at higher pH than the pKa. Hydrotalcite promotes both hydrophobic interaction and anion exchange. Hydrotalcite–smectite mixture was found to enhance clay dispersion and catalytic activity. This research allowed demonstrating that natural clay minerals can act both as adsorbents for LA extract from fermentation broths and as catalysts for adsorbent regeneration. The results obtained herein provide valuable and useful findings for envisaging seed-free milk clotting in dairy technologies.     

Bowtie-free graphs and generic automorphisms

We show that the countable universal ω-categorical bowtie-free graph admits generic automorphisms. Moreover, we show that this graph is not finitely homogenisable.     

ChemInform Abstract: Polymorphism of New Rubidium Magnesium Monophosphate.

RbMgPO₄ is synthesized by solid state reaction of stoichiometric mixtures of Rb₂CO₃, 4MgCO₃·Mg(OH)₂·5H₂O, and (NH₄)₂HPO₄ (900 °C, 12 h).     

Modeling Wormholes Generated by Dark Matter Galactic Halos in f(R)$f(R)$ Modified Gravity

Wormholes (WHs) are hypothetical topologically non-trivial spacetime structures that can be freely traversed by observers and connect two asymptotic regions or infinities. From the current theoretical development, the prospect of their existence is challenging but cannot be excluded. In this paper, generalized Ellis–Bronikov (GEB) traversable WH geometries for static and spherically symmetric spacetime in the background of $f(R)$ gravity is explored. First, the Tsujikawa-like $f(R)$ model and the shape function for the GEB model is considered, which depend on a sequence of simple Lorentzian WHs with two parameters: a free even integer exponent, n, besides the throat radius, r₀. One also consider that these WHs are generated by dark matter galactic halos (DMGHs), based on the three most common phenomenological models, viz., Navarro–Frenk–White (NFW), Thomas–Fermi (TF), and pseudo-isothermal (PI). In this concern, the satisfaction of the energy conditions (ECs) which are dependent on the dark matter (DM) models, viz., dominant energy condition (DEC) and strong energy condition (SEC) and those which are not dependent viz., null energy condition (NEC) and WEC at the WH throat and its neighborhood is investigated. Finally, the presence of exotic matter is confirmed by the violation of the NEC in all cases, revealing the supremacy and physical acceptability to support the existence of the WHs and making them compatible and traversable in Tsujikawa's-like $f(R)$ model.