LSmn系列表面化学性质与胶束化作用

通过表面张力的测定, 研究了十二烷基聚氧乙烯聚氧丙烯醚(LSmn)系列表面活性剂LS36、LS45、LS54在溶液表面吸附和形成胶束的热力学函数随温度的变化. 给出了它们在水溶液中的二组分相图.结果表明, LS36、LS45、LS54的表面活性都较高. 在25～50 ℃范围内, 临界胶束浓度(cmc)和平衡表面张力分别在4.44×10－6～17.3×10－6 mol•L－1和30.1～33.5 mN•m－1之间, 表面吸附和形成胶束的自由能分别在－40.0～－49.5 kJ•mol－1和－27.2～－33.1 kJ•mol－1之间.不论是在溶液表面吸附还是形成胶束均为熵驱动过程.其中LS36由于含具有亲水能力较强的聚氧乙烯基团(EO)成分较低, 因此不论其浊点还是其表面吸附和形成胶束的热力学函数均与LS45、LS54具有较大差异.     

Fabrication of prussian blue/multi-walled carbon nanotubes modified electrode for electrochemical sensing of hydroxylamine

We are presenting a sensor for hydroxylamine that is based on an glassy carbon electrode modified with nanoparticles of Prussian Blue and with multi-walled carbon nanotubes (MWCNTs). The sensing material was synthesized using a mixture of ferric chloride and potassium ferricyanide solution in the presence of MWCNTs under ambient conditions. Characterization was done by scanning electron microscopy, UV-vis spectroscopy, Fourier transform infrared absorption spectrum and cyclic voltammetry. The modified electrode showed two well-defined pairs of redox peaks and dramatic catalytic activity towards the electro-oxidation of hydroxylamine with a linear response ranging from 1.5 µM to 2.0 mM. In addition, tests show the sensor exhibited outstanding stability and reproducibility.     

New-generation biomedical materials: Peptide dendrimers and their application in biomedicine

Peptide dendrimers are attractive synthetic polymers and have been widely used as a new generation of biomaterials in recent years. Peptide dendrimers, as well as general dendrimers, may be synthesized to reach nano sizes, and display well-defined architectures, highly-branched structures, high density of functional terminal groups, and controllable molecular weights. On the other hand, peptide dendrimers have properties similar to proteins and some special characteristics, such as good biocompatibility, water solubility and resistance to proteolytic digestion. Due to these advantages, peptide dendrimers have received considerable attention in biomedicine. This review focuses on the development of peptide dendrimers with emphasis on their applications both in diagnostics and in therapy.     

Novel Designs for Centrifugal Countercurrent chromatography: V. Comparative Studies on Performance of Various Column Configurations

The conventional toroidal coil in centrifugal countercurrent chromatography has a low level of stationary phase retention, since a half of each helical turn is entirely occupied by the mobile phase. In order to cope with this problem, several new column designs including zigzag, saw-tooth and figure-8 patterns have been introduced and their performance was compared in terms of retention of the stationary phase (Sf), peak resolution (Rs), theoretical plate number (N) and column pressures. Overall results of experiments indicate that the figure-8 column yields the highest Rs when the lower phase is used as the mobile phase. Since the column pressure of all these new columns are much lower than that in the traditional toroidal coil column, the separation efficiency can be improved using a long separation column without a risk of column damage by high back pressure.     

Structural study of acetogenins by tandem mass spectrometry under high and low collision energy

Collision‐induced dissociation experiments of seven annonaceous acetogenins were carried out under high and low collision energy conditions. Each compound was studied as protonated or deprotonated and lithium‐ or sodium‐ cationized molecules, using ElectroSpray Ionisation (ESI) with a hybrid linear trap/orbitrap mass spectrometer (LTQ‐Orbitrap®). The same ion species were studied with a Matrix‐Assisted Laser Desorption Ionisation (MALDI) tandem mass spectrometer in a high collision energy regime (1 or 2 keV). Although each of the techniques showed some limitations in the detection of functional groups, unambiguous structural identification of the acetogenins was obtained. MALDI ToF‐ToF has the advantage over ESI‐based methods to provide mass spectra rich in informative fragments which allows the confirmation of some functional groups position. By contrast, ESI‐LTQ‐Orbitrap® analysis has the advantage over MALDI that the mass spectra are relatively simple with only fragments close to the functional groups. However, this technique needs to carry out experiments both in negative and positive ionization modes. Copyright © 2010 John Wiley & Sons, Ltd.     

A general synthetic procedure for 2-chloromethyl-4(3H)-quinazolinone derivatives and their utilization in the preparation of novel anticancer agents with 4-anilinoquinazoline scaffolds

In our ongoing research on novel anticancer agents with 4-anilinoquinazoline scaffolds, a series of novel 2-chloromethyl-4(3H)-quinazolinones were needed as key intermediates. An improved one-step synthesis of 2-chloromethyl-4(3H)-quinazolinones utilizing o-anthranilic acids as starting materials was described. Based on it, 2-hydroxy-methyl-4(3H)-quinazolinones were conveniently prepared in one pot. Moreover, two novel 4-anilinoquinazoline derivatives substituted with chloromethyl groups at the 2-position were synthesized and showed promising anticancer activity in vitro.     

Synthesis of magnetic/luminescent alginate-templated composite microparticles with temperature-dependent photoluminescence under high-frequency magnetic field

Highly magnetic luminescent alginate-templated composite microparticles were successfully synthesized by a novel process combining emulsification and layer-by-layer self-assembly techniques. The composite microparticles were characterized by ζ-potential analyzer, transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscope, fluorescence spectrophotometer, and vibrating sample magnetometer. Experimental observations indicated that the composite microparticles had excellent magnetic properties, and its photoluminescence could be precisely controlled by varying the number of deposition cycles of polyelectrolytes and CdTe/polyelectrolyte multilayers. Moreover, the composite microparticles could be heated up in a high-frequency magnetic field and demonstrated linear temperature-dependent photoluminescence over the range from room temperature to hyperthermia temperature. The composite microparticles are expected to be promising candidates for biomedical applications, such as immunoassay, biosensing and imaging, and cancer diagnosis and treatment.     

Morphology controllable synthesis and luminescence properties of NaLa(WO4)2:Eu microcrystals

NaLa(WO₄)₂:Eu microcrystals with shapes of four-arris shuttle, quadrangled star, and quadrangled dendrite were hydrothermally synthesized at 180 °C for 16 h. The concentration of the reactants and cetyltrimethyl ammonium bromide (CTAB) influenced the morphologies of the products. As La(NO₃)₃, Na₂WO₄ and CTAB was 0.375, 1.0, and 1.0 mmol, respectively, four-arris shuttle was obtained. As the concentration of the reactants doubled and the amount of CTAB ranged from 0.4 to 2.0 mmol, quadrangled dendrite, quadrangled star and four-arris shuttle were prepared, respectively. Luminescence intensity measurement of the three morphologies of NaLa(WO₄)₂:Eu showed that quadrangled dendrite was the strongest and four-arris shuttle was the lowest.     

Structural determination of aspericins A?C,new furan and pyran derivates from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61, by 1D and 2D NMR spectroscopy

Three new furan and pyran derivatives named aspericins A? C (1–3), as well as a known asperic acid (4), have been isolated from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61. The complete ¹H and ¹³C NMR assignments for the new compounds were carried out using ¹H, ¹³C, DEPT, COSY, HMQC, HMBC, and NOESY NMR experiments. Compounds 1–3 were evaluated for their cytotoxic activities on P388, A549, HL‐60, and BEL‐7420 cell lines by the MTT and SRB methods. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis,characterization, and crystallization of thermoplastic aromatic semi‐crystalline poly(ester‐imide)s based on bis(trimellitic acid anhydride) phenyl ester

A high molecular weight aromatic homopoly(ester‐imide) (homoPEI) was synthesized from homopoly(ester‐amic acids) (homoPEAA), which was obtained from the reaction of bis(trimellitic acid anhydride) phenyl ester (BTAH) with 4‐4'‐oxydianiline ether (ODA). This homoPEI was melt‐processable semi‐crystalline polymer and displayed dual endothermic transitions which were attributed to the different levels of crystal perfection and size in the crystal structures. Four high molecular weight aromatic copoly(ester‐imide)s (coPEIs) were synthesized via copoly(ester‐amic acids)s (coPEAA) from the reaction of 4, 4'‐oxydiphthalic anhydride (ODPA) and BTAH with ODA. The molar percentage of BTAH varied from 10 to 40%. When the molar percentages of BTAH were 30 and 40%, the resulting two coPEIs were crystallinable and their melting temperatures were 361°C and 356/371°C, respectively. Differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD) results indicated that the crystal structures included short segments of BTAH/ODA and ODPA/ODA. The initial crystallization of the two coPEIs took place during imidization process. Thermogravimetric (TA) and mechanical analysis confirmed that both homoPEI and coPEIs showed almost no weight loss until 400°C in N₂ and good mechanical properties. Copyright © 2009 John Wiley & Sons, Ltd.