超细粒子催化剂作用下碳酸二甲酯的合成

采用浸渍法制备了酸碱双功能催化剂 ,经过高温焙烧和气流粉碎得到超细粒子催化剂。结果表明 ,该超细催化剂对于由CO2 直接合成碳酸二甲酯的反应具有优良的催化活性 ,选择性和收率都要优于常规催化剂 ;结合反应精馏设备 ,可以将碳酸二甲酯的收率由 4 0 %提高至 70 %。     

Thermoreversible Siloxane Networks: Soft Biomaterials with Widely Tunable Viscoelasticity

Polysiloxane elastomers represent a widely utilized soft material with excellent rubber‐like elasticity, biocompatibility, and biodurability; however, there is a lack of an effective and straightforward approach to manipulate the material's viscoelastic response. A facile hydrosilylation reaction is employed to integrate ureidopyrimidinone hydrogen‐bonding side‐groups into linear and crosslinked siloxane polymers to achieve biocompatible soft materials with a highly tunable viscoelastic relaxation timescale. Stacking of H‐bonded moieties is avoided in the designed macromolecular architectures with tight, side‐groups substituents. The obtained siloxane network features the presence of both covalent crosslinks and truly thermoreversible crosslinks, and can be formulated across a broad material design space including elastic solids, recoverable viscoelastic solids, and viscous liquids. The elastomers exhibit unique temperature‐dependent shape‐memory capability and show good cytocompatibility. Importantly, a deformed material's shape‐recovery occurs regardless of external triggering, and through manipulation of network formulations, the shape‐recovery timescale can be easily tuned from seconds to days, opening new possibilities for biomedical, healthcare, and soft material applications.     

纳米金刚石膜的成核及生长特性研究

采用直流等离子体喷射化学气相沉积(DC arc pla sma jet)系统制备了纳米金刚石膜(NCD),研究了不同的金刚石成核剂溶液对NCD 膜的成核及生长的影响。研究表明,在成核剂溶液中添加二甲基亚砜(DMSO)后成核密度明显 得到提高,而 且制备的NCD膜晶粒分布均匀、致密。当金刚石粉体作为成核剂时,随着其粒径 的增大,NCD膜成核密度下降,晶粒的尺寸均匀性也变差,而粒径为5nm的金刚石纳米粒 子作为成核剂时,NCD膜晶粒间结合致密、颗粒分布均匀。最后,选择5nm的金刚石纳米 粒子和丙酮/DMSO配制的分散液作为成核剂配方,经过60min的生长 ,制备了粒径为50～70 nm的结晶性和品质良好的NCD膜,适用于高频声表面波(SAW)器件及各种光学窗口的研制。     

二(二甲苯基)丙烷合成工艺的研究

二氯丙烷(DCP)与二甲苯在混合金属氯化物催化剂(HD90)作用下合成二(二甲苯基)丙烷,生产过程简单,产品收率高。在60—80℃的温度下,二甲苯与二氯丙烷摩尔比为6∶1,HD用量50克/摩尔DCP的条件下反应5—6小时,二(二甲苯基)丙烷的收率可达88％以上。     

Buckwheat trypsin inhibitor enters Hep G2 cells by clathrin-dependent endocytosis

Recombinant buckwheat trypsin inhibitor (rBTI) was studied to evaluate if it could enter cancer cells and to determine the mechanism. Fluorescein isothiocyanate-labelled buckwheat trypsin inhibitor (FITC-BTI) entered Hep G2 cells in a concentration-dependent manner. FITC-BTI colocalised with labelled transferrin (Tf) in the punctate structure, implying that rBTI enters Hep G2 cells by clathrin-dependent endocytosis. Incubation of Hep G2 cells with different chemical inhibitors abolished diffuse, but not punctate fluorescence, thus indicating that membrane potential plays a critical role in this process. Impairment of clathrin-mediated endocytosis by RNAi with clathrin heavy chain greatly reduced or completely abolished both diffuse and punctate fluorescence, further supporting a theory of a single route of endocytosis. Consistent with our working hypothesis, Hep G2 cells which were arrested in the M phase did not show any vesicular or diffuse FITC-BTI. We conclude from these results that both endocytosis and membrane potential are required for rBTI entry into Hep G2 cells.     

棉织物用三嗪类磷系阻燃剂的制备及应用

以亚磷酸二甲酯和三聚氯氰为原料制备了含三嗪活性基的棉织物阻燃整理剂,并应用于棉织物,研究了各种工艺条件如阻燃剂用量、整理液pH值、焙烘温度及添加剂对阻燃效果的影响,并确定了最佳工艺.     

有机溶剂溶解法结合电感耦合等离子体发射光谱法直接测定软胶囊剂型保健食品中的钙和铁

目的 建立电感耦合等离子体发射光谱法(inductively coupled plasma optical emission spectrometry,ICP-OES)测定软胶囊剂型保健食品中的钙和铁含量的方法。方法 软胶囊剂型保健食品经水-硝酸-二甲亚砜混合溶液溶解后,使用电感耦合等离子体发射光谱仪,直接测定其中的钙和铁含量。结果 钙元素方法的检出限为3 mg/kg,定量限为9 mg/kg,钙元素的回收率在92.2%～96.7%之间,相对标准偏差(relative standard deviations,RSDs)在3.2%～8.8%之间。铁元素方法的检出限为0.6 mg/kg,定量限为2 mg/kg,铁元素的回收率在91.8%～96.7%之间,RSDs在1.8%～11.9%之间。实际样品检测时,同时采用了本方法与GB 5009.268—2016《食品安全国家标准食品中多元素的测定》(第二法),两种方法所得结果没有明显差异。结论 本方法在前处理时,不再使用传统的微波消解等方法,操作简单、快捷、准确度高,可以用于软胶囊剂型保健食品中钙和铁的检测。     

预混合饲料中维生素A 3种提取方法的比较研究

目的比较预混合饲料中维生素A的3种提取方法。方法抽取10个预混合饲料样品,比较皂化提取法、直接提取法、二甲基亚砜(dimethyl sulfoxide, DMSO)提取法实验过程和维生素A的检测结果。结果皂化提取法提取过程时间(t=130.4min)较长,步骤(21步)繁杂,较其他2种提取方法检测结果准确性较差,平行性较差。直接提取法与DMSO提取法提取过程时间较短,步骤较简便,检测结果准确性较好,平行性较好。结论直接提取法可以作为快速检测预混合饲料中维生素A含量的手段,但检测结果使用受到GB/T17817-2010《饲料中维生素A的测定高效液相色谱法》限制。皂化提取法可用于低含量复杂样品检测。DMSO法提取法,相较于皂化提取法,操作简便,测试快速,检测值准确性较好,平行性较好,能过有效弥补直接提取法与皂化提取法的缺点。     

DETERMINATION OF DIMETHYL SUPLHIDE IN BEER BY GAS CHROMATOGRAPHY — COLLABORATIVE TRIAL

The Analysis Committee has collaboratively tested both routine headspace gas chromatographic methods and a standardised method for the determination of dimethyl sulphide in beer using the flame photometric and flame ionisation detectors available in the participating laboratories. The mean repeatability value (r₉₅) was 7.8 μg/litre for the concentration range 12–65 μg/litre, and the reproducibility value (R₉₅) showed the relationship R₉₅ = 18.1 + 0.452m μg/litre to the concentration (m). No differences in precision were attributed either to the methods or the types of detectors used.     

高效液相色谱法测定调味面制品中 富马酸二甲酯

目的 建立调味面制品中富马酸二甲酯快速、灵敏的高效液相色谱测定方法。方法 色谱柱为ODS-C18 4.6 mm×250 mm,流动相为甲醇 （0.02 mol/L）乙酸铵（55:45）。样品粉碎用氨水甲醇溶液超声提取后调节pH为6,经0.45 μm滤膜过滤,进样测定,保留时间定性,峰面积定量。结果 标准曲线线性良好,方法线性范围0.25~10 mg/L,线性相关系数为0.9995,检出限为0.03 mg/kg,定量限为0.1 mg/kg,加标回收率在94.0%~102.5%范围内,相对标准偏差在3.6%~5.2%之间。结论 该方法操作简便、具有灵敏高、准确性好、无杂质干扰等优点,可用于调味面制品中富马酸二甲酯的测定。