Neoagarooligosaccharide Protects against Hepatic Fibrosis via Inhibition of TGF-β/Smad Signaling Pathway

Hepatic fibrosis occurs when liver tissue becomes scarred from repetitive liver injury and inflammatory responses; it can progress to cirrhosis and eventually to hepatocellular carcinoma. Previously, we reported that neoagarooligosaccharides (NAOs), produced by the hydrolysis of agar by β-agarases, have hepatoprotective effects against acetaminophen overdose-induced acute liver injury. However, the effect of NAOs on chronic liver injury, including hepatic fibrosis, has not yet been elucidated. Therefore, we examined whether NAOs protect against fibrogenesis in vitro and in vivo. NAOs ameliorated PAI-1, α-SMA, CTGF and fibronectin protein expression and decreased mRNA levels of fibrogenic genes in TGF-β-treated LX-2 cells. Furthermore, downstream of TGF-β, the Smad signaling pathway was inhibited by NAOs in LX-2 cells. Treatment with NAOs diminished the severity of hepatic injury, as evidenced by reduction in serum alanine aminotransferase and aspartate aminotransferase levels, in carbon tetrachloride (CCl₄)-induced liver fibrosis mouse models. Moreover, NAOs markedly blocked histopathological changes and collagen accumulation, as shown by H&E and Sirius red staining, respectively. Finally, NAOs antagonized the CCl₄-induced upregulation of the protein and mRNA levels of fibrogenic genes in the liver. In conclusion, our findings suggest that NAOs may be a promising candidate for the prevention and treatment of chronic liver injury via inhibition of the TGF-β/Smad signaling pathway.     

Changes in the content and antioxidative activity of β-carotene and its metabolite vitamin A during gastrointestinal digestion and absorption and optimisation of HPLC-based detection

The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results.     

三氯乙酸终止液对木瓜蛋白酶酶活测定的影响研究

本实验研究了不同的三氯乙酸终止液,对木瓜蛋白酶酶活的影响。通过使用两种检测方法,不同配方的三氯乙酸终止液进行实验。结果表明,使用两种不同配方的三氯乙酸终止液所得的结果相差2倍多。用不同稀释浓度的三氯乙酸终止液,在高浓度时,不同浓度的三氯乙酸终止液得到的结果差别很大,随着三氯乙酸浓度的降低,所测得的酶活不断升高;但是在低浓度时,不同浓度的三氯乙酸终止液得到的结果差别不大。     

芽孢杆菌Bacillus sp.dwc-2对模拟地下水中U(Ⅵ)的还原行为研究

在厌氧条件下研究了西南地区一种典型土壤微生物芽孢杆菌Bacillus sp.dwc-2对模拟地下水中U(Ⅵ)的还原行为，重点考察了时间、无机阴离子、腐殖酸（HA）及富里酸（FA）对还原的影响，并利用TEM、EDS、SAED和XPS对还原后的样品进行了表征。结果表明：在pH=7.0、c_NaHCO3=5 mmol/L和T=303 K条件下，Bacillus sp.dwc-2对U(Ⅵ)的还原率随时间的增加而增加，24 h内最大还原率为12.2%，此后则随时间的增加逐渐降低；HA和FA对U(Ⅵ)的微生物还原行为有一定影响，其中HA和FA浓度为25 mg/L时，U(Ⅵ)的还原在24 h最明显，其还原率分别为14.2%和16.2%，但随着HA和FA浓度的继续增加，因在U(Ⅵ)离子与HA、FA形成的配合物表面形成致密的腐殖层，抑制了电子的转移，阻止了U(Ⅵ)的还原。此外，研究表明HCO₃^-也会抑制U(Ⅵ)的还原。TEM-SAED和XPS分析证实了还原过程中U(Ⅳ)的存在。上述结果可为真实环境中微生物还原U(Ⅵ)提供基础数据和参考。     

高精度薄壁钢套类零件制造工艺

薄壁钢套类零件是机械制造中常碰到的一类难加工零件,由于其不同的功能用途和典型结构特点,其制造有一定难度,在实际生产过程中,经常出现加工制造后的零件尺寸精度、形状精度、形位精度达不到使用及设计要求。本文较系统地阐述了薄壁钢套类零件的典型制造工艺方法以及在制造过程中的变形分析和应对措施。     

黑龙江省节水增粮行动(2012—2015年)实施方案

文章通过对黑龙江省高效节水现状,存在问题的分析,结合黑龙江省高效节水发展的支撑能力,阐述黑龙江省节水增粮目标、任务及总体布局,为黑龙江省2012—2015年节水增粮实施提供依据。     

In situ characterization of LiY(WO4)2 nanotubes for electrochemical energy storage

Here, LiY(WO₄)₂ nanotubes are prepared via a feasible electrospinning technique. This new anode material shows excellent electrochemical properties. The capacity loss of LiY(WO₄)₂ nanotubes is as low as 6.9% after 156 cycles, while bulk LiY(WO₄)₂ presents the capacity loss higher than 55.0%. Even after 600 long-life cycles, the capacity loss of the nanotubes is only 9%. It can be seen that the hollow structure with a rough surface and a porous morphology contributes to the improvement of electrochemical performance. Furthermore, online X-ray diffraction (XRD) method is firstly applied to understand the lithium ions insertion/extraction mechanism of LiY(WO₄)₂ nanotubes. It can be concluded that it is an asymmetrical two-phase reaction. A phase transformation from LiY(WO₄)₂ to Li₃Y(WO₄)₂ can be obviously seen from the in situ XRD during discharge process. While Li₂Y(WO₄)₂ appears as an intermediate phase with a reverse charge reaction. In addition, in situ XRD also demonstrates that LiY(WO₄)₂ nanotubes have surprised electrochemical reversibility. All the above results indicate that LiY(WO₄)₂ nanotubes can be expected to be anode candidate for rechargeable lithium ion batteries (LIBs).     

超支化镍系催化剂构效关系及催化乙烯齐聚机理

采用1.0G超支化大分子（1.0G）、3-取代水杨醛和NiCl₂·6H₂O为原料，依次经席夫碱反应和络合反应合成了3种新型具有不同取代基位阻的超支化水杨醛亚胺配体及其镍系催化剂，利用红外光谱（FTIR）、核磁共振氢谱（¹H NMR）、紫外光谱（UV-vis）、电喷雾质谱（ESI-MS）及电感耦合等离子体质谱（ICP-MS）等方法对合成出产物的结构进行表征。考察了配体空间位阻、溶剂种类、助催化剂种类及反应条件对催化乙烯齐聚性能的影响。研究结果表明，配体空间位阻对催化乙烯齐聚性能有较大的影响，当以甲苯为溶剂、甲基铝氧烷（MAO）为助催化剂，在最佳反应条件下，超支化邻苯基水杨醛亚胺镍系催化剂催化乙烯齐聚的活性为2.81×10⁵g/(mol Ni·h)，对高碳烯烃（C₁₀₊）的选择性为34.28%。此外，在超支化水杨醛亚胺镍系催化剂催化性能评价的基础上，对其催化乙烯齐聚的机理进行研究。     

锂辉石-氧化钙烧结法提锂的物相重构与动力学

对锂辉石-氧化钙烧结过程进行热力学分析，绘制了各反应Gibbs自由能与温度的关系图。结果表明，Al₂O₃会优先和Na₂O、Li₂O、K₂O反应，然后与CaO反应生成CaO·Al₂O₃，而且烧结温度需高于1060℃以保证LiAlSi₂O₆能够完成晶形转变。并探讨了锂辉石-氧化钙烧结法提锂的反应机理。考察了不同烧结条件对锂浸出率的影响并对熟料进行X射线衍射（XRD）分析表征。实验结果表明，在配料比为1∶1.25、烧结温度1150℃、烧结时间60min时，锂的浸出率达到92.14%，熟料中的主要物相为Ca₂SiO₄与LiAlO₂。利用XRD和扫描电镜-能谱联用仪（SEM-EDS）对熟料与浸出渣的物相、显微形貌及元素分布情况进行了分析表征。为了确定烧结反应的控制性步骤，在最优烧结条件的基础上对烧结过程进行动力学分析，结果表明，锂辉石-氧化钙烧结体系属于球形颗粒三维界面化学反应控制，烧结过程的动力学拟合方程为\mathrm{1}-{(\mathrm{1}-x)}^{\mathrm{1}/\mathrm{3}}=\mathrm{0.00677}t。