Thiazolidinediones: An In–Depth Study of Their Synthesis and Application to Medicinal Chemistry in the Treatment of Diabetes Mellitus

2,4-Thiazolidinedione (TZD) is a privileged and highly utilised scaffold for the development of pharmaceutically active compounds. This sulfur-containing heterocycle is a versatile pharmacophore that confers a diverse range of pharmacological activities. TZD has been shown to exhibit biological action towards a vast range of targets interesting to medicinal chemists. In this review, we attempt to provide insight into both the historical conventional and the use of novel methodologies to synthesise the TZD core framework. Further to this, synthetic procedures utilised to substitute the TZD molecule at the activated methylene C₅ and N₃ position are reviewed. Finally, research into developing clinical agents, which act as modulators of peroxisome proliferator-activated receptors gamma (PPARγ), protein tyrosine phosphatase 1B (PTP1B) and aldose reductase 2 (ALR2), are discussed. These are the three most targeted receptors for the treatment of diabetes mellitus (DM).     

In-situ synthesis of 15R-Sialon from Al-Si3N4-Al2O3 composite at 1500°C via liquid-phase sintering

In this study, alumina-based composite with 12 wt% Al and 16 wt% Si₃N₄ was designed to achieve the synthesis of 15R-Sialon reinforced alumina composite. To investigate the reaction mechanism, two-step sintered Al-Si₃N₄-Al₂O₃ samples at different temperatures ranging from 600°C to 1500°C were prepared and characterized via X-ray diffraction and scanning electron microscope (SEM). The results revealed that 15R-Sialon was synthesized at 1500°C through a novel liquid Si phase sintering and Si₃N₄ played as a precursor and a reactant. First, Si₃N₄ precursor reacted with Al to form intermediate phases AlN and Si, which were not further transformed below 1400°C. When the sintering temperature was 1500°C, the formed Si presented as a liquid phase, under the influence of which plate-like15R-Sialon was generated from Al₂O₃, residual Si₃N₄, and derived AlN. The obtained Si was also involved in the synthesis of 15R-Sialon and completely transformed. In addition to the AlN from Si₃N₄, the AlN deriving from the nitridation of Al may not react with liquid Si. Compared to 15R-Sialon from liquid Si, plate-like 15R-Sialon with smaller size was generated from AlN, SiO, and O₂.     

Borage Oil Enhances Lamellar Body Content and Alters Fatty Acid Composition of Epidermal Ceramides in Essential Fatty Acid-Deficient Guinea Pigs

Borage oil [BO: 40.9% linoleic acid (LNA) and 24.0% γ-linolenic acid (GLA)] reverses disrupted epidermal lipid barrier in essential fatty acid deficiency (EFAD). We determined the effects of BO on lamellar body (LB) content and LNA and GLA incorporation into epidermal ceramide 1 (CER1) and epidermal ceramide 2 (CER2), major barrier lipids. EFAD was induced in guinea pigs by a diet of 6% hydrogenated coconut oil (HCO) for 10 weeks (group HCO) or 8 weeks followed by 6% BO for 2 weeks (group HCO + BO). LB content and LNA and GLA incorporation into CER1 were higher in group HCO + BO than in group HCO. Small but significant levels of LNA, GLA, and their C20-metabolized fatty acids [dihomo-γ-linolenic acid (DGLA) and arachidonic acid (ARA)] were incorporated into CER2, where ARA was detected at a level lower than LNA, but DGLA incorporation exceeded that for GLA in group HCO + BO. Dietary BO enhanced LB content and differential incorporation of GLA into CER1 and DGLA into CER2.     

拟薄水铝石中硫酸根的存在形式及其对拟薄水铝石性质的影响

A series of pseudo-boehmite samples with their sulfate radicals（SO42-） concentration ranging from 0.9% to 3.0%were prepared by the reaction of NaAlO2 solution on Al2（SO4）3 solution. The existing form of sulfate radicals was investigated.Results have shown that sulfates in pseudo-boehmite included two parts, the soluble sulfate radicals and the insolublesulfate radicals, which accounted for 99% of the total amount of sulfate radicals. XRD, low-temperature N2-adsorption, andTEM were used to characterize the properties of these pseudo-boehmite samples. Results have shown that the relative crystallinityand crystal size of pseudo-boehmite decreased with the increase of sulfate radicals in the support. In the meanwhile,the bound water content in pseudo-boehmite increased. The TEM images of pseudo-boehmite indicated that the pseudoboehmitewas prone to become amorphous hydrated alumina. However, the effect of sulfate content on the specific surfacearea and pore structure of aluminium oxide was insignificant.     

Development of oxidation resistant coatings for titanium alloys

Abstract

This work addresses the development of a coating to protect the titanium alloy designated IMI834 from oxidation and alpha case formation. This is to enable the safe use of the alloy at relatively high operating temperatures and thereby significantly improve the efficiency of aeroengines. Two different types of surface modification techniques have been employed to coat the titanium alloy: electrodeposition and pack aluminising. Cyclic isothermal oxidation studies revealed that platinum aluminide coating obtained by electrodeposition followed by pack aluminising exhibits good oxidation resistance compared with that exhibited by a plain aluminide coating. Based on results obtained by different techniques, it is suggested that platinum aluminide is a prospective coating material for preventing alpha case formation and protecting against oxidation in components fabricated from titanium alloy IMI834.     

三种植物叶片类胡萝卜素含量的比较分析

以红继木、红苋和七彩扶桑的叶片为材料,采用丙酮-乙醇法提取,利用紫外-可见分光光度计对三种植物叶片中胡萝卜素、叶黄素和总类胡萝卜素的含量进行了测定。结果表明,胡萝卜素含量:红苋>红继木>七彩扶桑;叶黄素含量:七彩扶桑>红苋>红继木;总类胡萝卜素含量:红苋>红继木>七彩扶桑。     

Synthesis of Dy2O3 nanoparticles via hydroxide precipitation： effect of calcination temperature

This work described the preparation of dysprosium oxide, Dy2O3, nanoparticles using the homogeneous precipitation method. Dy3+ ions were precipitated using NaOH solution. The obtained product was filtered, dried, and then calcined for 1 h at the temperature range of 300–700 °C in static air. The calcination temperature of the Dy-precursor was chosen based on its decomposition as indicated by the TGA analysis. The crystalline structure and surface morphology of the calcined solids were studied by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The obtained results revealed that Dy2O3 with crystallites size of 11–21 nm was formed at 500 °C. Such value increased to 25–37 nm for the sample calcined at 700 °C.     

热力耦合对一种第四代镍基单晶高温合金1100℃蠕变组织演变的影响

以一种第四代镍基单晶高温合金为研究对象,采用变截面蠕变试样,在1100℃、43~96 MPa条件下进行200 h蠕变中断实验,利用SEM和TEM观察了微观组织演变规律,利用同步辐射高能XRD和EPMA分析了高温低应力条件下镍基单晶高温合金的蠕变组织演变。结果表明:随着应力的增大,镍基单晶高温合金的γ′相体积分数降低,筏化程度增大且筏排厚度下降,同时,γ相通道宽度逐渐增大,而γ/γ’两相界面位错网间距逐渐减小。固溶强化元素Re、Mo和Cr等在γ相中的富集导致γ/γ’两相错配度绝对值增大。蠕变过程中γ’相体积分数降低和γ’相筏排厚度减小显著降低了合金的强度。另外,位错在γ′相溶解所导致的弯曲相界处的塞积,使位错易于切入γ′相,也是镍基单晶高温合金室温硬度下降的重要原因。     

Influence of chromium on microstructure and etching behaviour of new Ni–Fe–Al based alloy

In the present study, the influence of chromium on the microstructure and etching behaviour of the polycrystalline alloy Ni–13Fe–8Al–4Ti (at-%) has been examined. The alloy was recently designed for nanomembrane fabrication, but although it showed the necessary γ/γ′ microstructure with cubic, well aligned γ′ precipitates, it proved to be unsuitable for nanomembrane fabrication as the γ matrix was dissolved during chemical etching. To obtain the passivation of the γ matrix, chromium has been added in further modifications containing 1, 2, 3 and 4 at-% chromium. Moreover, the influence of heat treatment and the different cooling rates of heat treatment in air/vacuum have been investigated. For chemical phase extraction, the application of the chemical etchants MoO₃ acid and ‘G’ etchant has been examined, the formability was characterised by Vickers hardness testing. The main purpose of the present study, namely the passivation of the γ matrix, could be achieved by the addition of 4 at-% chromium and etching with ‘G’ etchant.