Reaction of Epichlorohydrin with 2-Aminobenzothiazole and Its Derivatives

We have shown that 2-aminobenzothiazoles when reacted with epichlorohydrin form 3-hydroxytetrahydropyrimido[2,1-b]benzothiazolium chlorides, while 2-iminobenzothiazolines form 2-(-chloro--hydroxypropyl)iminobenzothiazolines.     

Preparation of thermo- and redox-responsive branched polymers composed of three-armed oligo(ethylene glycol)

We herein report the preparation of thermo- and redox-responsive branched polymers by the condensation reaction of three-armed oligo(ethylene glycol) (trisOEG) and cystamine (CA). The prepared branched polymers exhibited a soluble–insoluble transition at a lower critical solution temperature (LCST) and formed coacervate droplets through a liquid–liquid phase separation process. We then demonstrated control of the LCSTs of the branched polymers by varying the feed ratio of CA and the surrounding salt concentration close to body temperature. In addition, the trisOEG-cys _x polymer formed coacervate droplets above the LCST, in which hydrophobic molecules were condensed. The redox response of the branched polymers was also investigated. Interestingly, the branched polymers degraded to low-molecular-weight materials (i.e., trisOEG) in the presence of dithiothereitol as a reducing agent through cleavage of the disulfide bond of CA. This facile preparation of branched polymers is expected to be valuable in the context of functional biomedical materials and modifiers for materials surfaces, such as the bases for drug delivery carriers and separation materials. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2623–2629     

Enhanced visible light photocatalysis of TiO2 by Co-modification with Eu and Au nanoparticles

TiO₂ photocatalysis has been studied widely in environment protection and energy generation applications. But, the intrinsic absence of visible light response and the high recombination rate of photo-generated charge carriers significantly limited the efficiency of photocatalysis with TiO₂ materials. Herein, a facile approach was constructed to develop visible-light-induced TiO₂ photocatalysis by co-modification with Eu and Au nanoparticles. The synthesized Au/Eu-TiO₂ material was characterized by XRD, SEM, TEM, DRS, XPS, and N₂ adsorption measurements. Visible light catalytic performance of the Au/Eu-TiO₂ catalyst was evaluated by using the photodegradation of RhB as a model reaction. It was shown that this Au/Eu-TiO₂ exhibited a better photocatalytic activity than the single Au modified TiO₂ (Au/TiO₂) or the single Eu modified TiO₂ catalyst (Eu/TiO₂), and also exhibited a good reusability for the targeted reaction. This remarkably improved performance of Au/Eu-TiO₂ could be attributed to the synergetic effect of Eu and Au co-decoration, which not only enhanced visible light absorption but also promoted charge carriers transfers as evidenced by DRS, XPS and transient photocurrent spectra. Moreover, a possible reaction mechanism for the Au/Eu-TiO₂ photocatalysis was proposed.     

Synthesis,characterization, density functional theory,X‐ray study,thermal stability,and biological and MOE relevance of metal complexes of griseofulvin

Metal(II) and metal(III) coordination compounds of griseofulvin (GFV) drug were synthesized. The structure of the ligand was determined on the basis of elemental analyses, infrared and ¹H NMR spectroscopies and thermal studies. GFV behaved as a neutral tridentate chelating agent and coordinated to metal ions through three oxygen atoms: two methoxy groups and oxygen atom of furan ring. Metal complexes were characterized by means of elemental analyses and molar conductance, spectral (infrared, electron spin resonance) and thermal studies. All the complexes showed molar conductance behaviour corresponding to an electrolytic nature. All the complexes showed octahedral geometry, except [Zn(GFV)Cl]Cl that showed tetrahedral geometry. Density functional theory (DFT) calculations were employed to understand and estimate the contribution of each interaction in the formation of the assembly using several theoretical models. The computed parameters from DFT calculations for structure optimizations and vibrational frequencies were in good agreement with the experimental data. Newly synthesized metal complexes in addition to GFV were examined against opportunistic pathogens. The biological applications of complexes were studied with two Gram‐positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram‐negative bacteria (Escherichia coli and Neisseria gonorrhoeae) as well as their antifungal activity against Candida albicans. Results suggested that metal complexes were more biologically sensitive than free ligand. The complexes showed a moderate inhibition of MCF7 breast cancer cell line growth. Molecular docking studies further helped in understanding the mode of action of the compounds through their various interactions with the crystal structures of: human serum albumin (PDB: 5FUO), Staphylococcus aureus nucleoside (PDB: 3Q8U), human acetylcholinesterase (PDB: 1B41) and the human DNA–Topo I complex (PDB: 1SC7).     

Synthesis of CuS nanoparticles loaded on activated carbon composite for ultrasound‐assisted adsorption removal of dye pollutants: Process optimization using CCD‐RSM,equilibrium and kinetic studies

In this study, the CuS nanoparticles loaded on activated carbon (CuS‐NPs‐AC) composite was synthesized and then, characterized by XRD and FE‐SEM analyses. The prepared composite was used as a potential adsorbent for the simultaneous ultrasound‐assisted removal of Indigo Carmine (IC) and Safranin‐O (SO). The CuS‐NPs‐AC dose (0.01‐0.03 g), sonication time (1‐5 min), initial SO concentration (5‐15 mg L^‐1) and initial IC concentration (5‐15 mg L^‐1) as expectable effective parameters were studied by central composite design (CCD) under response surface methodology (RSM) to obtain an useful knowledge about the effect of simultaneous interaction between IC and SO on their removal percentage. The optimum SO and IC removal percentages were determined to be 98.24 and 97.15% at pH = 6, 0.03 g of the CuS‐NPs‐AC, 3 min sonication time, 12 and 10 mg L^‐1 of IC and SO. The values of coefficient of determination (R²) for SO and IC were 0.9608 and 0.9796, respectively, indicating the favorable fitness of the experimental data to the second order polynomial regression model. The isotherm data were well correlated with Freundlich model. The maximum monolayer adsorption capacities of 87.5 and 69.90 mg g^‐1 at room temperature for IC and SO in the investigated binary system expressed the high efficiency of the novel adsorbent for water cleanup within a short time. The investigation of correlation between time and rate of adsorption revealed that IC and SO adsorption onto the CuS‐NPs‐AC followed pseudo‐second‐order and intra‐particle diffusion simultaneously.     

功能化磁性纳米粒子在乳状液制备及破乳中的应用及作用机制

功能化磁性纳米粒子因其独特的理化性质,在乳状液制备与破乳领域的应用受到广泛关注。本文归纳了功能化磁性纳米粒子的制备方法、合成结构与特征性质,阐述了其在乳状液制备及破乳中的应用过程,重点分析了磁性纳米粒子在溶液中良好分散、稳定吸附于油水界面排布为膜结构的作用行为,尤其是磁性纳米粒子的磁响应特征对乳状液中界面性质、液滴形貌及运动状态的影响,并进一步总结出其表面性质及作用行为对稳定乳状液或使乳状液破乳的规律。针对磁性纳米粒子对乳状液稳定性影响规律的探究可为其在应用领域提供理论支持。最后本文就功能化磁性纳米粒子研究中亟待解决的新问题作出展望。     

Agent-Based Network Modeling Study of Immune Responses in Progression of Ulcerative Colitis

Ulcerative colitis, an inflammatory bowel disease, is a chronic inflammatory disorder that results in ulcers of the colon and rectum without known etiology.Ulcerative colitis causes a huge public health care burden particularly in developed countries.Many studies suggest that ulcerative colitis results from an abnormal immune response against components of commensal microbiota in genetically susceptible individuals.However, understanding of the disease mechanisms at cellular and molecular levels remains largely elusive.In this paper, a network model is developed based on our previous study and computer simulations are performed using an agent-based network modeling to elucidate the dynamics of immune response in ulcerative colitis progression.Our modeling study identifies several important positive feedback loops as a driving force for ulcerative colitis initiation and progression.The results demonstrate that although immune response in ulcerative colitis patients is dominated by anti-inflammatory/regulatory cells such as alternatively activated macrophages and type Ⅱ natural killer T cells, proinflammatory cells including classically activated macrophages, T helper 1 and T helper 17 cells, and their secreted cytokines tumor necrosis factor-α, interleukin-12, interleukin-23, interleukin-17 and interferon-γ remain at certain levels (lower than those in Crohn's disease, another inflammatory bowel disease).Long-term exposure to these proinflammatory components, causes mucosal tissue damage persistently, leading to ulcerative colitis.Our simulation results are qualitatively in agreement with clinical and laboratory measurements, offering novel insight into the disease mechanisms.