Development of an information-intensive structure–activity relationship model and its application to human respiratory chemical sensitizers

Structure–activity relationship (SAR) models are recognized as powerful tools to predict the toxicologic potential of new or untested chemicals and also provide insight into possible mechanisms of toxicity. Models have been based on physicochemical attributes and structural features of chemicals. We describe herein the development of a new SAR modeling algorithm called cat-SAR that is capable of analyzing and predicting chemical activity from divergent biological response data. The cat-SAR program develops chemical fragment-based SAR models from categorical biological response data (e.g. toxicologically active and inactive compounds). The database selected for model development was a published set of chemicals documented to cause respiratory hypersensitivity in humans. Two models were generated that differed only in that one model included explicate hydrogen containing fragments. The predictive abilities of the models were tested using leave-one-out cross-validation tests. One model had a sensitivity of 0.94 and specificity of 0.87 yielding an overall correct prediction of 91%. The second model had a sensitivity of 0.89, specificity of 0.95 and overall correct prediction of 92%. The demonstrated predictive capabilities of the cat-SAR approach, together with its modeling flexibility and design transparency, suggest the potential for its widespread applicability to toxicity prediction and for deriving mechanistic insight into toxicologic effects.     

One inorganic-organic hybrid derived from reduced molybdophosphate and trinuclear cadmium(Ⅱ) fragment

One new polyoxometalate (POM)-based inorganic-organic hybrid [Cd3Ⅱ(HPO4)(Hbpp)(H2O)2]{CdⅡ[P4- Mo6O28H3.5(OH)3]2} (H4tpb)·7H2O (1) (bpp = 1,3-bis-(4-pyridyl)propane, tpb = 1,2,4,5-tetra(4-pyridyl)-benzene) constructed from reduced molybdophosphate [P4Mo6O28H3.5(OH)3]5.5- (P4Mo6), trinuclear CdⅡ-phosphate-Hbpp fragment and protonated tpb has been hydrothermally synthesized and structurally characterized by IR, elemental analyses and single crystal X-ray diffraction. The complex 1 crystallizes in the monoclinic system with the space group P21/c and cell parameters of a = 15.672(12)Å, b = 23.839(19)Å, c = 27.654(2)Å, β = 115.850(10)8, V = 9297.9(12) Å3, Z = 4, R1 = 0.0534 and wR2 = 0.1135. In complex 1, the P4Mo6 units are bridged by CdⅡ ions to form the classic sandwich-type [Cd(P4Mo6)2] dimers, which are further connected into a two dimensional network via the trinuclear CdⅡ subunits. The tpb is synthesized in situ from the bpp ligands and connects the adjacent 2D layers into a 3D supramolecular framework through hydrogen bonding interactions. The electrochemical and fluorescent properties of complex 1 have been investigated.     

Preparation and evaluation of a novel molecularly imprinted SPE monolithic capillary column for the determination of auramine O in shrimp

A novel method combining molecular imprinting and SPE was developed in a capillary column for the determination of auramine O in shrimp. The capillary monolithic column was prepared by UV‐initiated in situ polymerization, using auramine O as template and methacrylic acid and ethylene dimethacrylate as functional monomer and cross‐linker, respectively. The properties of the prepared capillary monolithic column were investigated under the optimized conditions coupled with HPLC, and then the morphologies of the inner polymers were characterized by SEM. The calibration curve was expressed as A = 103C + 19.8 (r = 0.9992) with a linear range of 0.25–25.0 μg/mL, and the recoveries of auramine O at different concentrations in shrimp ranged from 90.5 to 92.4% with RSDs ranging from 2.1 to 4.4%. The capacities of the molecularly imprinted polymer and nonimprinted polymer columns were 0.722 and 0.147 μg/mg, respectively, and the LOD (S/N = 3) of auramine O in shrimp was 17.85 μg/kg. Under the selected conditions, the enrichment factors obtained were higher than 70‐fold. The results indicate that the prepared molecularly imprinted capillary monolithic column was reliable and applicable to the analysis of auramine O in shrimp.     

Solid phase microextraction fills the gap in tissue sampling protocols

Metabolomics and biomarkers discovery are an integral part of bioanalysis. However, untargeted tissue analysis remains as the bottleneck of such studies due to the invasiveness of sample collection, as well as the laborious and time-consuming sample preparation protocols. In the current study, technology integrating in vivo sampling, sample preparation and global extraction of metabolites – solid phase microextraction was presented and evaluated during liver and lung transplantation in pig model. Sampling approaches, including selection of the probe, transportation, storage conditions and analyte coverage were discussed. The applicability of the method for metabolomics studies was demonstrated during lung transplantation experiments.     

Synthesis and Characterization of Iron Nanowires

The iron nanowires can be fabricated via the process in which sodium borohydride reduces iron salts in external magnetic field. The iron nanowires are found to be covered by passivated layers of iron oxide which prevent the oxidation of iron nanowires. In this process, the boron will include in iron nanowires. The average length and diameter of iron nanowires is around 1.2 micrometers and 60 nanometers, respectively. According to ICP results, the contents of B and Fe are about 1.98 wt% and 87.04 wt%, respectively, in iron nanowires. A wide variety of equipment is used to investigate the morphological, microchemical, and structural characteristics of the newly synthesized iron nanowires ––– e.g., XRD, FE‐SEM, HR‐TEM, VSM and XANES. XANES analysis indicates the boron in iron nanowires exists in the form of B₂O₃. The saturation magnetization and the coercive force of iron nanowires are 157.93 emu/g and 9.74 Oe, respectively. In‐situ images of synthesized iron nanowires during reduction process in magnetic field are observed by NSRRC transmission X‐ray microscope. Thus, this study develop a novel process to produce iron nanowires with large quantitates and can control its length and diameter by various the concentration of precursors for various applications.     

Synthesis and Photocatalytic Properties of Nano‐crystalline In2O3

A nano‐crystalline In₂O₃ was synthesized using calcinations methods and was used as a photocatalyst to degrade sulfan blue (SB) dye. In addition, this study addresses the conditions of the degradation and the factors that influenced the catalysis. In₂O₃ was prepared by calcining In(OH)₃ at heat ranges of 100–700 °C for 24 h. The In₂O₃ was characterized using field emission scanning electron microscopy (FE‐SEM), an X‐ray diffractometer (XRD), thermogravimetric analysis (TGA), and high‐resolution X‐ray photoelectron spectroscopy (HR‐XPS). The activities of these samples were tested for the photocatalytic degradation of SB dye. The results indicated that the In(OH)₃ that was calcined at 300 °C for 24 h had the best performance.     

SnCl4/Sn catalyzed chemoselective reduction of glycopyranosyl azides for the synthesis of diversely functionalized glycopyranosyl chloroacetamides

A method for the chemoselective reduction of glycopyranosyl azides using SnCl₄ and tin metal as the reducing agent followed by in situ chloroacetylation of the synthesized glycopyranosyl amine was developed. This reaction is applicable to diversely functionalized glycopyranosyl azides for the synthesis of glycopyranosyl chloroacetamides.     

Determination of UV filters in river water samples by in‐line SPE‐CE‐MS

The use of SPE coupled in‐line to CE using electrospray MS detection (in‐line SPE‐CE‐ESI‐MS) was investigated for the preconcentration and separation of four UV filters: benzophenone‐3, 2,2‐dihydroxy‐4‐methoxybenzophenone, 2,4‐dihydroxybenzophenone and 2‐phenylbenzimidazole‐5‐sulphonic acid. First, a CE‐ESI‐MS method was developed and validated using standard samples, obtaining LODs between 0.06 μg/mL and 0.40 μg/mL. For the in‐line SPE‐CE‐ESI‐MS method, three different sorbents were evaluated and compared: Oasis HLB, Oasis MCX, and Oasis MAX. For each sorbent, the main parameters affecting the preconcentration performance, such as sample pH, volume, and composition of the elution plug, and sample injection time were studied. The Oasis MCX sorbent showed the best performance and was used to validate the in‐line SPE‐CE‐ESI‐MS methodology. The LODs reached for standard samples were in the range between 0.01 and 0.05 ng/mL with good reproducibility and the developed strategy provided sensitivity enhancement factors between 3400‐fold and 34 000‐fold. The applicability of the developed methodology was demonstrated by the analysis of UV filters in river water samples.     

基于Diels-Alder点击反应构建壳聚糖-O-聚乙二醇接枝共聚物

通过Diels-Alder(D-A)反应,合成了具有规整化学结构的接枝共聚物,壳聚糖-O-聚乙二醇(CS-O-PEG).D-A反应所需双烯体(呋喃环)通过糠基硫醇与端甲基丙烯酸酯聚乙二醇之间的巯基-丙烯酸酯(thio-acrylate)反应合成得到;马来酰亚胺基丙酸通过活泼酯法偶联到十二烷基硫酸钠-壳聚糖复合物(SCC)羟基上,从而获得亲双烯体.采用红外光谱(FTIR)和核磁共振(1H-NMR)表征了中间产物与最终产物的结构,并用原位核磁监测D-A反应及其逆反应过程.结果表明,聚乙二醇双烯体可在水介质中温和条件下定量接枝到壳聚糖羟基上,反应具有点击特征;同时,聚乙二醇与壳聚糖之间的连接键在高温下(90℃)可通过D-A逆反应而发生断裂.