鸡骨素及其酶解液的美拉德反应产物挥发性风味成分比较分析

利用固相微萃取/气相色谱-质谱(SPME/GC-MS)联用与电子鼻(E-Nose)嗅探技术对鸡骨素美拉德反应产物(MRPs1)及鸡骨素酶解液美拉德反应产物(MRPs2)中的挥发性风味成分进行比较分析。在两种产物中共鉴定出77种挥发性化学成分,其中醇类18种、醛酮类23种、酸类3种、酯类10种、杂环类7种及其他类16种,两种产物中共有成分26种。与MRPs1相比,MRPs2中醛酮、杂环类化合物的相对含量较高,但前者的酯类物质含量更为丰富。(E)-2-辛烯-1-醇、(6Z,9Z)-十五碳二烯-1-醇、苯甲醛、辛醛、6-甲基-5-庚烯-2-酮、2-乙基-3-羟基-4(4H)-吡喃酮、2,3,5-三甲基-6-乙基吡嗪、2-[(甲基二硫基)甲基]呋喃构成了MRPs2的特有成分,γ-丁位十二内酯为MRPs1的特有成分。在两种反应产物中,除4-甲基-5-羟乙基噻唑的相对含量均较高外(MRP1相似文献   

Electrogenerated Fe(I) Porphyrins: Efficient Electrocatalysts for Reductive Dechlorination of DDT in N,N′‐Dimethylformamide

Two iron(I) porphyrins were electrogenerated and then utilized as catalysts for the reductive dechlorination of 1,1‐bis(4‐chlorophenyl)‐2,2,2‐trichloroethane (DDT) in N,N′‐dimethylformamide. No reaction is observed between DDT and the Fe(III) or Fe(II) forms of the porphyrin, but the electrogenerated Fe(I) porphyrin efficiently catalyzes the electroreduction of DDT to give (1,1‐bis(4‐chlorophenyl)‐2,2‐dichloroethane) DDD, (1,1‐bis(4‐chlorophenyl)‐2,2‐dichloroethylene) DDE and (1,1‐bis(4‐chlorophenyl)‐2‐dichloroethane) DDMU as determined by GC‐MS analysis. The reductive dechlorination was monitored by electrochemistry, controlled potential electrolysis and spectroelectrochemistry and a mechanism for the reaction involving the reduced porphyrins and DDT is proposed. Comparisons are also made between the catalytic properties of metalloporphyrins containing iron, cobalt and manganese central metal ions under the same solution conditions.     

Electrochemical assay of the relationship between the inhibition of phosphatidylinositol 3-kinase pathway and estrogen receptor expression in breast cancer

Breast cancer has become one of the most threatening diseases to women throughout the world. Emerging evidence implies that estrogen receptor (ER) and phosphatidylinositol 3-kinase (PI3K) pathways play central roles in both breast cancer progression and response to therapy. In this work, we have probed into ER expression related to the PI3K pathway at the protein level with an electrochemical technique based on the detection of ER proteins in nuclear extracts with an Exonuclease III protection-based strategy. Experimental results show that an increased number of ER proteins can be detected upon PI3K inhibition, demonstrating the reversal effect of the PI3K inhibitor on ER expression. Moreover, treatment with different concentrations of the PI3K inhibitor NVP-BEZ235 can result in a dose-dependent alteration of ER protein levels, implying an intimate link between ER and PI3K pathways. This work may be a great help to understand the mysteries underlying PI3K-related endocrine resistance and to evaluate the effect of therapeutic interventions in the future.     

Patterning Surfaces for Controlled Platelet Adhesion and Detection of Dysfunctional Platelets

Platelets play a fundamental role in thrombus formation and in the pathogenesis of arterial thrombosis. Patterning surfaces for controlled platelet adhesion paves the way for adhesion and activation mechanisms in platelets and detection of platelet functional defects. Here, a new and simple method based on controlled polymerization of 2‐methacryloyloxyethyl phosphorylcholine (MPC) on the surface of styrene‐block‐(ethylene‐co‐butylene)‐block‐styrene (SEBS) is shown. The competition between polymerization and degradation enables platelet adhesion on SEBS to be switched on and off. The adhesive sites of the platelets can be down to single cell level, and the dysfunctional platelets can be quantitatively detected.

     

HPLC-DAD data coupled with second-order calibration method applied to food analysis: Simultaneous determination of six benzoylurea insecticides in various fruit samples by selecting time region of chromatogram

This work presents a novel application of second-order calibration based on self-weighted alternating trilinear decomposition(SWATLD)algorithm for analyzing the HPLC-DAD data.The proposed method makes it possible to simultaneously determine teflubenzuron,hexaflumuron,flufenoxuron,chlorfluazuron,diflubenzuron and benzoylurea in different fruit samples,i.e.pear,apple and banana,in the selected time region of chromatogram.The concentration,elution time and spectral information of these benzoylurea insecticides are selectively extracted from complex matrices even in the presence of unknown interferences.The root-mean-square error of prediction(RMSEP)and figures of merit,including sensitivity(SEN),selectivity(SEL)and limit of detection(LOD)are employed to access the performance of the method.The LODs obtained for these insecticides are within the range 0.017–0.26 ppm in pears,0.039–0.33 ppm in apples,0.041–0.44 ppm in bananas,respectively.Such a chemometrics-based protocol holds great potential to be extended as a promising alternative for more practical applications in food safety and quality monitoring.     

Characterization of cellulose-based electrospun nanofiber membrane and its adsorptive behaviours using Cu(II), Cd(II), Pb(II) as models

Science China Chemistry - Nanofiber membranes from the composite of cellulose acetate/polyvinylpyrrolidone were prepared using electrospinning technique. After treated with water and alcoholic KOH...     

Design, synthesis and in vitro antitumor evaluation of novel diaryl urea derivatives bearing sulfonamide moiety

A novel series of diaryl urea derivatives bearing sulfonamide moiety have been designed and synthesized.Their in vitro antitumor effect against human cancer cell lines MX-1,A375,HepG2,Ketr3 and HT-29 was screened and evaluated by the standard MTT assay with sorafenib as the positive control.Some of the compounds showed significant inhibitory activity against multiple cell lines compared to sorafenib.In particular,2,6-dimethyl-4-{6-[3-(4-chloro-3-(trifluoromethyl)phenyl)urea]naphthalen-2-yl}sulfonyl morpholine(10d)was found to be the most potent against A375,HepG2 and Ketr3 with IC50values of 0.65–0.97mol/L,which were 5–20-fold more potent than sorafenib.Compound 10d emerged as a valuable lead for further optimization.     

Synthesis of purpurin-18 imide derivatives from chlorophyll-a and -b by modifications and functionalizations along their peripheries

The methyl pheophorbide-a and methyl pheophorbide-b were used as starting materials and converted to purpurin-18 ester by ring-opening and rearrangement reaction in their exocyclic ring. N-Substituted purpurin-18 imides were obtained from purpurin-18 ester through amidation reaction of six-membered cyclic anhydride. Further chemical modifications along their peripheries were carried out by a variety of common reactions, including electrophilic substitution, Wittig reaction, allomerization and Vilsmeier reaction, to afford the title compounds with long-wavelength absorption. The structures of all new chlorins were characterized by elemental analysis, IR, UV–vis and ¹H NMR spectra.     

Two lanthanum(III) complexes containing η2‐pyrazolate and η2‐1,2,4‐triazolate ligands: intramolecular C—H...N/O interactions and coordination geometries

The lanthanum(III) complexes tris(3,5‐diphenylpyrazolato‐κ²N,N′)tris(tetrahydrofuran‐κO)lanthanum(III) tetrahydrofuran monosolvate, [La(C₁₅H₁₁N₂)₃(C₄H₈O)₃]·C₄H₈O, (I), and tris(3,5‐diphenyl‐1,2,4‐triazolato‐κ²N¹,N²)tris(tetrahydrofuran‐κO)lanthanum(III), [La(C₁₄H₁₀N₃)₃(C₄H₈O)₃], (II), both contain La^III atoms coordinated by three heterocyclic ligands and three tetrahydrofuran ligands, but their coordination geometries differ. Complex (I) has a mer‐distorted octahedral geometry, while complex (II) has a fac‐distorted configuration. The difference in the coordination geometries and the existence of asymmetric La—N bonding in the two complexes is associated with intramolecular C—H...N/O interactions between the ligands.