P&T/GC/MS/SIS法在加氯消毒饮用水中痕量挥发性氯代烃测定中的应用

以吹扫捕集-气相色谱-质谱联用选择离子存储法(P&T/GC/MS/SIS)测定自来水中微量挥发性氯代烃,确定了最佳定性定量操作条件,同时探讨了改变原水中加氯量对三氯甲烷形成量的影响.当进样量为5.00mL时,四种氯代烃的线性范围为0～50ug/L,相关系数达0.9991以上;相对标准偏差RSD＜9.8%;相对误差＜7.6%,样品加标回收率为88%～128%,检测限在0.0006～0.26μg·L-1.方法操作方便,结果令人满意.     

不饱和氯代烃制备不饱和醇的催化水解工艺研究

采用催化水解法为合成方法,开发了由不饱和氯代烃制备不饱和醇的高效新工艺。研究了催化剂种类和用量、助催化剂、氯代烃、反应时间和反应温度等因素对不饱和醇制备过程的影响规律。优化工艺为:催化剂Cu Cl/Na I为催化体系,用量均为氯代烃摩尔量的2%;反应温度为70℃;反应时间为6 h。在此条件下,不饱和醇的收率80%。当催化水解母液循环利用时,只需每次补加氯代烃摩尔量0.5%的催化剂,不饱和醇的收率基本不变。合成的不饱和醇经过了气相和核磁表征。     

3-甲基-2-丁烯-1-醇的催化水解工艺研究

以3-甲基-2-丁烯-1-氯为原料,合成3-甲基-2-丁烯-1-醇的催化水解工艺,利用气相色谱、红外光谱和核磁共振对所得产物进行了表征。通过正交试验讨论了催化剂种类、助催化剂种类、水解温度和水解液pH值对氯代烃的转化率和不饱和醇的选择性的影响。结果表明,最佳工艺条件为:n(氯代烃)∶n(CuCl)∶n(NaI)=1∶0.02∶0.02,水解温度为60℃,水解液pH=6。在此条件下,氯代烃的转化率达到97.83%,不饱和醇的选择性保持在94.19%。此外,研究了催化水解反应中副产物的产生机理及控制措施,提出了水解液循环利用过程中的催化效率保持的方法。     

原位修复氯代烃污染场地地下水的现场中试研究

以典型氯代烃污染场地为试验基地,采用原位注入方法,研究了添加强化药剂对地下水氯代烃厌氧还原脱氯降解和化学环境变化的影响。结果表明,强化药剂能有效促进氯代烃污染地下水的原位还原修复,且对1,1,1-三氯乙烷、1,1-二氯乙烷的去除效果(平均去除率>99%)好于对1,1-二氯乙烯的效果(平均去除率78.9%);药剂最佳作用时间为注入后90d内,最佳作用半径为1.5m,主要作用途径为药剂中缓释有机碳介导的厌氧生物还原脱氯。     

2-氯-3-硝基苯甲酸的分析

采用高效液相色谱仪建立了一种测定2-氯-3-硝基苯甲酸的定量定性分析方法,使用C₁₈为填充物的不锈钢柱;流动相为甲醇+0.1%磷酸水溶液,流速为1.0 mL/min,检测波长为236 nm,柱温为40℃进行检测。结果表明,2-氯-3-硝基苯甲酸的浓度和峰面积之间呈现出良好的线性相关性,其相关系数为0.999 9,标准偏差为0.15%,变异系数为0.16%,回收率为98.98%～100.44%。说明该方法操作简单,可确保2-氯-3-硝基苯甲酸生产过程中的定性和定量结果的重现性和准确度。     

2-甲基-4-氯苯氧乙酸在玉米植株、籽粒和土壤中的残留

研究了2-甲基-4-氯苯氧乙酸(简称2甲4氯)在玉米植株、籽粒和土壤中的残留分析方法及残留动态.植株和籽粒采用乙腈提取,乙二胺基-N-丙基净化,土壤采用0.1 mol/L氧氧化钾提取,盐酸调pH值至2,二氯甲烷萃取,UPLC-MS/MS测定.结果表明:2甲4氯在玉米植株、籽粒和土壤中的添加回收率分别为81.6%～95.0%、85.6%～98.4%、91.7%～102.0%;相对标准偏差分别为3.0%～7.4%、3.9%～7.7%、6.6%～9.0%.2甲4氯的最小检出量为0.005 ng,最低检出限为0.01 mg/kg.2甲4氯在植株和土壤中的半衰期分别为5.6～6.7 d和9.8～13.4 d,在植株中的消解速率大于在土壤中的消解速率.     

气相色谱-质谱法测定地下水中30种挥发性有机物

近几年来地下水污染状况越来越受到人们的重视,为开展国家地下水监测工程运行维护项目,根据《地下水质量标准》的要求本方法建立了适用于地下水中挥发性氯代烃、苯系物、氯代苯类等30种挥发性有机污染化合物(VOCs)的分析方法。本方法利用吹扫捕集器直接进样,经DB-5MS毛细管色谱柱分离,电子轰击电离(EI)检测,以内标法进行定量;30种VOCs样品平均加标回收率在83. 1%～112%之间,平均相对偏差在-9. 22%～5. 82%之间,方法的检出限范围在0. 05～0. 13μg/L。     

修正制品中氯代烃多组分检测技术研究及应用

应用带有电子捕获检测器的毛细管气相色谱法分析了修正制品中氯代烃多组分,用对测定无干扰的溶剂萃取、离心过滤后,以溴丙烷为内标物测定了其中的8种对人体有害的氯代烃,即二氯甲烷、三氯甲烷、三氯乙烯、四氯化碳,1,1-二氯乙烷、1,2-二氯乙烷、1,1,1-三氯乙烷及1,1,2-三氯乙烷。方法的检出限(3S/N)在0.010~2.5mg/kg范围内,相对标准偏差(n=6)小于5%,标准加入回收率在90.2%~98.8%之间。     

22种氯代烃标准气体的瓶内均匀性研究

分子量大的氯代烃在气瓶内可能出现分层、沸点高的氯代烃可能在气瓶内吸附,从而引起挥发性氯代烃混合标准气体出现瓶内不均匀的现象。研究确定了氮气中22种挥发性氯代烃标准气体瓶内均匀性的实验方法,并通过考察量值随样品压力的变化来评价样品在瓶内的均匀性。根据实验结果分别计算了22种氯代烃瓶内不均匀性所引起的不确定度,结果显示在样品压力2 MPa时,1,1,2,2-四氯乙烷、间二氯苯、对二氯苯、邻二氯苯的量值显著变大,其瓶内不均匀性所引起的不确定度2%。样品压力2 MPa,22种挥发性氯代烃标准气体会出现不均匀现象,因此样品的最低使用压力为2 MPa。     

化工场地氯代烃污染地下水氧化修复研究

以广西某化工污染场地多种氯代烃污染地下水为研究对象,通过碱激活过硫酸钠和改性芬顿两种环境友好型氧化体系对地下水中多种氯代烃进行效果研究。结果表明:以1,1-二氯乙烷为主要污染物的地下水使用1.5%过硫酸钠+0.03%氢氧化钠或0.28%硫酸亚铁+0.53%焦磷酸钠+0.80%过氧化氢处理后可达到修复目标,pH满足地下水Ⅳ类标准;对于三氯甲烷为主要污染物的地下水使用配比为4.0%过硫酸钠+0.05%氢氧化钠或0.42%硫酸亚铁+0.80%焦磷酸钠+2.97%过氧化氢处理后可达到污染物修复目标。碱激活过硫酸钠和改性芬顿可有效氧化修复地下水氯代烃污染物。     

Synthesis of Aqueous CdTe/CdS/ZnS Core/shell/shell Quantum Dots by a Chemical Aerosol Flow Method

This work described a continuous method to synthesize CdTe/CdS/ZnS core/shell/shell quantum dots. In an integrated system by flawlessly combining the chemical aerosol flow system working at high temperature (200–300°C) to generate CdTe/CdS intermediate products and an additional heat-up setup at relatively low temperature to overcoat the ZnS shells, the CdTe/CdS/ZnS multishell structures were realized. The as-synthesized CdTe/CdS/ZnS core/shell/shell quantum dots are characterized by photoluminescence spectra, X-ray diffraction (XRD), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). Fluorescence and XRD results confirm that the obtained quantum dots have a core/shell/shell structure. It shows the highest quantum yield above 45% when compared to the rhodamine 6G. The core/shell/shell QDs were more stable via the oxidation experiment by H₂O₂.     

非热等离子体协同Mn-Ce/La/γ-Al2O3催化剂去除甲苯

采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al₂O₃催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al₂O₃、Mn-Ce/γ-Al₂O₃、Mn-La/γ-Al₂O₃催化剂,从甲苯去除率、产物O₃生成、CO_x选择性及其他副产物生成情况考察比较了空管放电、协同催化剂放电时催化降解甲苯性能,并对催化剂进行了BET、SEM、H₂-TPR和ICP-OES表征研究。结果表明：稀土助剂的加入有助于提高甲苯去除率及降低程度,且La催化性能优于Ce_.,当外加电压22 kV、气量6 L·min^-1、甲苯初始浓度600 mg·m^-3时,Mn-La/γ-Al₂O₃催化剂对甲苯去除率达到72.74%。H₂-TPR结果表明,稀土助剂的加入提高了催化剂低温活性及储氧能力,添加La的效果优于Ce。催化剂有助于抑制副产物O₃生成,提高CO₂和CO_x选择性。     

Sol–Gel Processing and Characterization of Pure and Metal-Doped SnO2 Thin Films

A chloride-based inorganic sol–gel route was used for preparing pure and metal (osmium, nickel, palladium, platinum)-doped SnO₂ sol. SnCl₄ was first reacted with propanol, then the resulting compound was hydrolyzed and subsequently mixed with solutions of the metal dopants. The obtained sols were used for depositing thin films by spin coating or for preparing powders by solvent evaporation at 110°C. FTIR spectroscopy and thermal analysis of the powders revealed that chlorine still bound to tin stabilized the sol against gelation by hindering the condensation reactions. Film characterizations showed that platinum and palladium, unlike nickel and osmium, were likely to form nanoparticles in the SnO₂ lattice. This result was discussed with regard to the different ways that platinum and palladium, on one hand, and nickel and osmium, on the other, modified the growth of SnO₂ grains and the film roughness and morphology. Dopants that formed nanoparticles (platinum, palladium) resulted in the roughest film, while dopants that did not form particles (nickel, osmium) resulted in SnO₂ grain size very close to that of pure SnO₂.     

高岭土补强NR/SBR/BR的红外光谱研究

通过FT-IR仪,对制备的高岭土/NR/SBR/BR复合材料进行了系统的分析和研究.结果表明:硅烷偶联剂与高岭石表面产生了化学键合;在复合材料的硫化过程中硫磺与橡胶大分子形成了C-Sx-C键;高岭土的加入能够影响C-Sx-C键的形成,其内羟基能与橡胶大分子反应;高岭土在偶联剂的作用下融入橡胶基体中,提升了硫化胶的力学性能;FT-IR可以研究高岭土补强NR/SBR/BR复合材料的机理.     

Myostatin Knockout Affects Mitochondrial Function by Inhibiting the AMPK/SIRT1/PGC1α Pathway in Skeletal Muscle

Simple SummaryMyostatin (Mstn) is a negative regulator of skeletal muscle mass, and its deletion leads to reduced mitochondrial function. However, the exact regulatory mechanism remains unclear. In this study, we used CRISPR/Cas9 to generate myostatin-knockout (Mstn-KO) mice via pronuclear microinjection. The skeletal muscle of Mstn-KO mice significantly increased, and the basal metabolic rate, muscle ATP synthesis, mitochondrial respiratory chain complex activity, tricarboxylic acid cycle (TCA), and thermogenesis decreased. In the muscle tissue of Mstn-KO mice, the expression of SIRT1 and pAMPK decreased, and the acetylation modification of PGC-1α increased. Furthermore, the treatment of isolated muscle cells from Mstn-KO and wild-type mice with AMPK activator (AICAR) and AMPK inhibitor (Compound C) found that Compound C down-regulated the expression of pAMPK and SIRT1 and the activity of citrate synthase (CS), isocitrate dehydrogenase (ICDHm) and α-ketoglutarate acid dehydrogenase (α-KGDH) similar to that of Mstn-KO. However, AICAR partially reversed the inhibitory effect of Mstn-KO on the expression of pAMPK and SIRT1 and activity of three enzymes. Thus, Mstn-KO affects mitochondrial function by inhibiting the AMPK/SIRT1/PGC1α signaling pathway.AbstractMyostatin (Mstn) is a major negative regulator of skeletal muscle mass and initiates multiple metabolic changes. The deletion of the Mstn gene in mice leads to reduced mitochondrial functions. However, the underlying regulatory mechanisms remain unclear. In this study, we used CRISPR/Cas9 to generate myostatin-knockout (Mstn-KO) mice via pronuclear microinjection. Mstn-KO mice exhibited significantly larger skeletal muscles. Meanwhile, Mstn knockout regulated the organ weights of mice. Moreover, we found that Mstn knockout reduced the basal metabolic rate, muscle adenosine triphosphate (ATP) synthesis, activities of mitochondrial respiration chain complexes, tricarboxylic acid cycle (TCA) cycle, and thermogenesis. Mechanistically, expressions of silent information regulator 1 (SIRT1) and phosphorylated adenosine monophosphate-activated protein kinase (pAMPK) were down-regulated, while peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) acetylation modification increased in the Mstn-KO mice. Skeletal muscle cells from Mstn-KO and WT were treated with AMPK activator 5-aminoimidazole-4-carboxamide riboside (AICAR), and the AMPK inhibitor Compound C, respectively. Compared with the wild-type (WT) group, Compound C treatment further down-regulated the expression or activity of pAMPK, SIRT1, citrate synthase (CS), isocitrate dehydrogenase (ICDHm), and α-ketoglutarate acid dehydrogenase (α-KGDH) in Mstn-KO mice, while Mstn knockout inhibited the AICAR activation effect. Therefore, Mstn knockout affects mitochondrial function by inhibiting the AMPK/SIRT1/PGC1α signaling pathway. The present study reveals a new mechanism for Mstn knockout in regulating energy homeostasis.     

微波辅助制备Ni-W-P/γ-Al2O3煤焦油加氢催化剂

采用微波辅助浸渍法、微波管式焙烧制备了Ni-W-P/γ-Al₂O₃催化剂,并以中低温煤焦油轻油为原料,在固定床反应器装置上评价了催化剂的加氢活性。通过N₂吸附-脱附、GC-MS等方法对催化剂的物化性能及加氢产物油进行表征,并根据FHH模型,计算出催化剂的表面分形维数。结果表明,添加助剂P可调节催化剂的微观孔结构,改变催化剂的酸性分布与强度,并有助于加氢饱和反应的进行;当助剂P含量为0.9%时,催化剂的加氢脱硫、脱氮活性最高,加氢饱和性能最好;焙烧温度直接影响催化剂物性参数,当温度为500 ℃时,加氢活性最高、加氢产物品质最佳;微波焙烧相比常规制备方法,可增加晶粒烧结程度,形成更多三维孔隙结构,为加氢反应提供更大的表面和空间,且增加中等强度酸的酸量,更有助于表面活性组分的分散及硫化性的增强。     

Co-Cu-Ce-Fe/γ-Al_2O_3催化剂催化分解N_2O的性能

以等体积浸渍法制备γ-Al_2O_3负载的Co、Cu、Ce和Fe氧化物催化剂,利用正交试验设计实验条件,采用XRD、BET和H_2-TPR等对催化剂进行表征,并考察活性组分对催化剂催化分解N_2O活性的影响。结果表明,催化剂具有尖晶石结构,其BET比表面积随着金属氧化物负载量增加而降低。催化剂中铜的氧化物可以降低还原峰温度,进而明显提高催化活性,Co和Fe的加入对活性有一定的提高,Ce对催化活性没有明显影响。     

催化剂上丙烷氧化脱氢制丙烯

以浸渍法制备VMo/γ-Al₂O₃和VMoMg/γ-Al₂O₃催化剂,考察其催化丙烷氧化脱氢制丙烯的反应活性,采用XRD、UV-Vis DRS和In suit IR对催化剂进行表征。结果表明,V负载质量分数为3%、Mo负载质量分数为7%时的3V7Mo/γ-Al₂O₃催化剂表现出较好的催化性能;添加Mg后催化剂的催化性能有所改善,反应温度500 ℃时,丙烷转化率为18.19%,丙烯选择性74.76%。丙烷和丙烯在3V7Mo/γ-Al₂O₃和3V₇Mo₄Mg/γ-Al₂O₃催化剂上吸附后,C—H键的H与催化剂活性中心的晶格氧发生作用形成H—O键,且3V₇Mo₄Mg/γ-Al₂O₃催化剂上出现C—O键的温度比3V₇Mo/γ-Al₂O₃催化剂高,表明加入Mg有利于提高丙烯选择性。     

Triterpenoid Saponins from Stauntonia chinensis Ameliorate Insulin Resistance via the AMP-Activated Protein Kinase and IR/IRS-1/PI3K/Akt Pathways in Insulin-Resistant HepG2 Cells

Inflammation and oxidative stress play crucial roles in the etiology of type 2 diabetes mellitus. In this study, we examined the anti-diabetic effects of triterpenoid saponins extracted from Stauntonia chinensis on stimulating glucose uptake by insulin-resistant human HepG2 cells. The results showed that saponin 6 significantly increased glucose uptake and glucose catabolism. Saponin 6 also enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and activated the insulin receptor (IR)/insulin receptor substrate-1 (IRS-1)/phosphoinositide 3-kinase (PI3K)/Akt pathway. Therefore, our results suggest that saponins from S. chinensis improve glucose uptake and catabolism in hepatic cells by stimulating the AMPK and the IR/IRS-1/PI3K/Akt signaling pathways. The results also imply that saponins from S. chinensis can enhance glucose uptake and insulin sensitivity, representing a promising treatment for type 2 diabetes mellitus.