胶束液相色谱法测定乳制品中三聚氰胺

采用胶束液相色谱法直接测定乳制品中三聚氰胺。考察了表面活性剂的种类及浓度、有机改性剂种类及用量、柱温、流动相pH值等对三聚氰胺色谱保留时间的影响。结果表明:随着有机改性剂增加、十二烷基硫酸钠(SDS)浓度增大和流动相pH值增大,三聚氰胺的容量因子(k′)明显减小。在所选定的条件下,三聚氰胺与乳制品中其他组分之间具有较好的分离效果。三聚氰胺质量浓度在0.1～100 mg·L~(-1)范围内呈线性关系,检出限(3S/N)和测定下限(10S/N)分别达0.02,0.07 mg·kg~(-1)。对同一试样的9次平行测定结果的相对标准偏差为1.28%,平均加入回收率为97.64%～99.91%。     

应用壳聚糖-分子筛复合材料选择性吸附卷烟烟气中低分子醛酮

制备了3种壳聚糖-分子筛复合材料,并使用扫描电镜和ASAP 2020全自动吸附仪观测了复合材料的微观形态及其物理性质。对分别添加3种壳聚糖-分子筛复合材料、分子筛及壳聚糖的卷烟复合滤咀对主流烟气中低分子醛酮类化合物和其它有害物质(如焦油、尼古丁及一氧化碳等)的吸附效果进行了试验。结果表明:添加了壳聚糖-分子筛复合材料、分子筛及壳聚糖的卷烟滤咀对主流烟气中低分子醛酮类化合物均有较好的吸附作用,对焦油、烟碱量无明显影响;3种壳聚糖-分子筛复合材料对主流烟气中醛酮类化合物的吸附能力均优于其两种单体材料,该复合材料对一氧化碳有一定的吸附,且对抽吸品质有所改善,口感柔和,烟气刺激性降低。     

A new lignan from Gynostemma pentaphyllum

A new lignan ligballinone 1 with the know ligballinol 2 were isolated from plant Gynostemma pentaphyllum.Their structures were determined through spectroscopic methods including ESI-MS,1D and 2D NMR (1H,13C,DEPT,1H-1H COSY,HMQC,RMBC) and X-ray diffraction experiment for 2.     

Synthesis and cytotoxicity of novel podophyllotoxin derivatives

In order to find novel synthetic antitumor agents with superior cytotoxicity and overcoming multidrug resistance,a novel series of 4β-N-substituted podophyllotoxin derivatives were synthesized and evaluated as potential antitumor agents.Seven novel podophyllotoxin derivatives were synthesized by linking 4β-amino-4-deoxypodophyllotoxin with N-substituted 5-methylindol-3- yl-glyoxyl chlorides and tested against K562 and K562/A02 using SRB methods in vitro,KB and KBV using MTT methods in vitro.     

pH-sensitive polymer-assisted refolding of urea-denatured fibroblast growth factor

A pH-responsive polymer Eudragit S-100 has been found to assist in correct folding of FGF-2(fibroblast growth factor-2) denatured with 8 mol/L urea and 10 mmol/L dithiothreitol at pH 7.2.The refolding of FGF-2 was performed by directly diluting denatured FGF-2 into a refolding buffer containing Eudragit S-100.The ability of Eudragit S-100 to enhance protein refolding level was investigated using MTr method,fluorescence emission spectroscopy and reverse phase HPLC.On the other hand,the result shows the ab...     

A new compound from the fruit of Amorpha fruticosa and activity against acetaminophen-induced hepatotoxicity

A new isoflavone was obstained from the medicinal herb Amorpha fruticosa.It was elucidated asbenzopyran-12-one,1,4,10,11- tetrahydro-6′-[8′-(hydroxymethyl)ethenyl]-2,3-dimethoxy-8′-O-β-D-glucopyranosyl-O-α-D-arabinoside by spectroscopic methods including UV,IR,1D NMR and 2D NMR techniques.And the activity against acetaminophen-induced hepatotoxicity of this compound was also studied,and found this compound can protect liver obviously from hepatotoxicity induced by acetaminophen (AAP).     

Preparation of nucleoside-pyridine hybrids and pyridine attached acylureas from an unexpected uracil ring-opening and pyridine ring-forming sequence

Novel pyrimidine nucleoside-3,5-dicyanopyridine hybrids (4) or pyridine attached acylureas (5) were selectively and efficiently prepared from the reaction of 2′-deoxyuridin-5-yl-methylene malononitrile (1), malononitrile (2) and thiophenol (3) or from an unexpected uracil ring-opening and pyridine ring-forming sequence via the reaction of 1 and 3. It is the first time such a sequence has ever been reported.     

Synthesis and positive inotropic evaluation of 1-(benzylamino)-3-(4,5-di-hydro[1,2,4]trizaolo[4,3-a]quinolin-7-yloxy)propan-2-ol derivatives

In an attempt to search for more potent positive inotropic agents,a series of 1-(benzylamino)-3-(4,5-dihydro[1,2,4]trizaolo[4,3- a]quinolin-7-yloxy)propan-2-ol derivatives was synthesized in four steps using 6-hydroxy-3,4-dihydro-2(1H)-quinolinone as a starting material,and their positive inotropic activities were evaluated by measuring the coronary blood flow(CBF)and the left ventricular pressure(LVP)followed by calculating the rate of pressure development(dp/dt_(max)values)in the preparation of rat Lan...     

Real-time monitoring of DNAzyme cleavage process using fluorescent assay

Detection of deoxyribozyme(DNAzyme) cleavage process usually needs complex and time-consuming radial labeling,gel electrophoresis and autoradiography.This paper reported an approach to detect DNAzyme cleavage process in real time using a fluorescence probe.The probe was employed as DNAzyme substrate to convert directly the cleavage information into fluorescence signal in real time.Compared with traditional approach,this non-isotope method not only brought a convenient means to monitor the DNAzyme cleavag...     

A simple and efficient synthesis of 2-substituted benzothiazoles catalyzed by H_2O_2/HCl

A simple and efficient procedure for the synthesis of substituted benzothiazoles through condensation of 2-aminothiophenol with aromatic aldehydes in the presence of H_2O_2/HCl system in ethanol at room temperature is described.The target compounds have been characterized by ~1H NMR,~(13)C NMR,IR and MS.Short reaction time,easy and quick isolation of the products,and excellent yields are the main advantages of this procedure.