Analysis of the Binding Sites of Porcine Sialoadhesin Receptor with PRRSV

Porcine reproductive and respiratory syndrome virus (PRRSV) can infect pigs and cause enormous economic losses to the pig industry worldwide. Porcine sialoadhesin (pSN) and CD163 have been identified as key viral receptors on porcine alveolar macrophages (PAM), a main target cell infected by PRRSV. In this study, the protein structures of amino acids 1–119 from the pSN and cSN (cattle sialoadhesin) N-termini (excluding the 19-amino acid signal peptide) were modeled via homology modeling based on mSN (mouse sialoadhesin) template structures using bioinformatics tools. Subsequently, pSN and cSN homology structures were superposed onto the mSN protein structure to predict the binding sites of pSN. As a validation experiment, the SN N-terminus (including the wild-type and site-directed-mutant-types of pSN and cSN) was cloned and expressed as a SN-GFP chimera protein. The binding activity between SN and PRRSV was confirmed by WB (Western blotting), FAR-WB (far Western blotting), ELISA (enzyme-linked immunosorbent assay) and immunofluorescence assay. We found that the S107 amino acid residue in the pSN N-terminal played a crucial role in forming a special cavity, as well as a hydrogen bond for enhancing PRRSV binding during PRRSV infection. S107 may be glycosylated during PRRSV infection and may also be involved in forming the cavity for binding PRRSV along with other sites, including W2, Y44, S45, R97, R105, W106 and V109. Additionally, S107 might also be important for pSN binding with PRRSV. However, the function of these binding sites must be confirmed by further studies.     

Microwave hydrothermal synthesis and photocatalytic properties of TiO2/BiVO4 composite photocatalysts

TiO₂/BiVO₄ composite photocatalysts with heterojunction structures were synthesized by the one-step microwave hydrothermal method. The physical and photophysical properties of the as-prepared photocatalysts were fully characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), UV–vis diffuse reflectance spectra, photoluminescence (PL) and BET surface area analysis. The photocatalytic activities were evaluated by the decolorization of rhodamine B under UV and simulated sun-light irradiation. The results reveal that the as-prepared TiO₂/BiVO₄ composites exhibit higher photocatalytic activities than pure BiVO₄. The 20% TiO₂/BiVO₄ sample shows the best photocatalytic activity. The enhancement of photocatalytic activity is mainly attributed to the increasing separation rate of photogenerated charge carriers. The possible photocatalytic mechanism is discussed on the basis of the calculated energy band positions.     

固相萃取法与GC-FPD联用分析海水中13种有机磷

有机磷农药的广泛使用导致其不可避免地进入到环境中,不仅会影响生态环境,而且还会通过食物链富集进入到人体中,对人类健康造成影响.建立了固相萃取与GC-FPD联用的方法,并成功用于海水样品中敌敌畏等13种有机磷的分析.在中性条件下,100 mL水样经过HLB固相萃取小柱富集后,以二氯甲烷为洗脱溶剂进行洗脱,以HP-5柱为分...     

废CeOx-MnOx基SCR脱硝催化剂还原酸浸综合回收铈锰

废选择性催化还原（SCR）脱硝催化剂中含有大量的有价金属,直接废弃易造成资源浪费及环境污染。以废CeO _x -MnO _x 基SCR脱硝催化剂为原料,采用热力学分析结合湿法冶金实验方法,研究了浸出条件对Ce、Mn元素浸出率的影响。结果表明,废催化剂直接酸浸Ce、Mn元素浸出率低,还原-酸浸Ce、Mn元素热力学条件上可行,抗坏血酸对Ce、Mn高价氧化物有明显的还原作用。当抗坏血酸质量分数为30%、硫酸浓度2mol/L、液固比6∶1、搅拌速度350r/min、80℃恒温反应5h时,Ce、Mn的浸出率分别达到92.09%、95.51%。加入抗坏血酸后,部分Ce⁴⁺和Mn⁴⁺还原为Ce³⁺和Mn²⁺,Ce⁴⁺/Ce的比值由75.82%降低到71.62%,Mn⁴⁺/Mn的比值由29.39%降低到27.17%,同时削弱了高价Ce辅助低价Mn向高价Mn转化的作用,使得Ce、Mn高效浸出,为CeO _x -MnO _x 基废催化剂中Ce、Mn资源化利用奠定了基础。     

重组大肠杆菌1,2,4-丁三醇合成途径的平衡优化

1,2,4-丁三醇(1,2,4-butantriol,BT)属于非天然化学品,是军工材料1,2,4-丁三醇三硝酸酯的前体。在重组大肠杆菌中,木糖经脱氢、脱水、脱羧和还原合成BT。但途径各反应不平衡使得中间代谢物积累限制菌体生长和产物合成。本研究首先通过CRISPR/Cas9敲除基因yjh G和yqh D构建无本底表达宿主菌,随后利用不同启动子组合调节BT合成途径中基因xdh、yjh G和yqh D的表达。结果发现,以P_inv表达醇脱氢酶基因yqh D使BT产量达到14.4g/L;以P_tac表达脱氢酶基因xdh和P_{rrn HP1}表达脱水酶基因yjh G的组合方式,BT产量达到15.6g/L,比对照菌株KXW3009分别增加5.9%和14.7%。本研究通过对中间代谢物木糖酸合成和代谢的组合优化,促进了BT的合成,为后续研究提供了借鉴。     

Decolorization of methylene blue by heterogeneous Fenton reaction using Fe3−xTixO4 (0 ≤ x ≤ 0.78) at neutral pH values

In this work, a series of Fe_3−xTi_xO₄ (0 ≤ x ≤ 0.78) was synthesized using a new soft chemical method. The synthetic Fe_3−xTi_xO₄ were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Mössbauer spectroscopy, thermogravimetric and differential scanning calorimetry (TG–DSC) analyses. The results showed that they were spinel structures and Ti was introduced into their structures.Then, decolorization of methylene blue (MB) by Fe_3−xTi_xO₄ in the presence of H₂O₂ at neutral pH values was studied using UV–vis spectra, dissolved organic carbon (DOC) and element C analyses. Furthermore, the degradation products remained in reaction solution after the decolorization were identified using ionic chromatography (IC), ¹³C nuclear magnetic resonance spectra (NMR), liquid chromatography and mass spectrometry (LC–MS). Although small amounts of MB were mineralized, the aromatic rings in MB were destroyed completely after the decolorization. Decolorization of MB by Fe_3−xTi_xO₄ in the presence of H₂O₂ was promoted remarkably with the increase of Ti content in Fe_3−xTi_xO₄ due to the enhancement of both adsorption and degradation of MB on Fe_3−xTi_xO₄.     

铁酸铋功能陶瓷薄膜的液相自组装制备

利用自组装单层膜技术,以三氯十八烷基硅烷(octadecyl trichlorosilane,OTS)为模板,以硝酸铋和硝酸铁为原料,在玻璃基片上成功制备了铁酸铋(BiFeO3)晶态薄膜。采用接触角仪测量了紫外光照射后OTS单层膜的亲水性。通过X射线衍射、扫描电镜和能谱仪等表征了BiFeO3薄膜的物相、表面形貌及微观结构。结果表明:紫外光照射使OTS单层膜由原来的强疏水性转变为良好的亲水性,说明OTS自组装膜层表面已被羟基化。在70℃沉积8h并经600℃退火2h制备的BiFeO3薄膜结晶良好,薄膜样品的表面平整,厚度较为均匀,薄膜厚度约为100nm。     

氟碳铈矿制取高纯硝酸高铈铵的工艺研究

研究了以氟碳铈矿为主要原料制备高纯硝酸高铈铵的工艺技术,即通过氟碳铈矿焙烧、稀硫酸浸取、萃取剂选择性萃铈,然后用稀硝酸反萃,使高价铈从有机相进入水相,获得高价铈的硝酸溶液,加入固体硝酸铵反应得到高纯硝酸高铈铵复盐产品.讨论了氟碳铈矿的焙烧温度、酸浸和选择性萃铈的条件、反应时间对硝酸高铈铵纯度的影响,以及该工艺对环境的影响.该方法可以获得纯度达99%以上的硝酸高铈铵,且硝酸高铈铵的收率可达85%以上.     

300t精炼钢包温度场和应力场的有限元分析

在目前所用材质体系和砌筑结构的基础上,对精炼过程中的300 t精炼钢包剪切应力场、温度场和热应力场以及膨胀缝的最大接触应力进行了有限元研究.结果表明:在LF精炼过程中,渣线处的内衬砖最容易受冲刷和热应力的作用而损毁,需在保证良好抗渣性能的同时采用热膨胀系数低、抗冲刷性好的耐火内衬砖;膨胀缝的最大接触应力与膨胀缝的大小呈线性反比关系,以保持在0.8～1.8 mm之间为宜.     

分子印迹技术在甾类物质识别和分析中的应用

分子印迹技术在甾类分子识别和分析中的应用及取得的进展。