Preparation and properties of polymer and quantum dot composites

Quantum dots (QDs) were prepared in an organic system through a simple and low-cost wet chemistry method. Polymer beads with a diameter of 60–70 nm and specific functional groups were synthesized by a particular seeded emulsion polymerization technique. QDs were embedded in the polymer beads with the specific functional groups through dissolving and swelling method, which provided the condition for the conjunction of biomolecules and QDs as fluorescent probes. The prepared composites were characterized with UV-Vis, PL, TEM, FTIR, CLSM and conductance titration etc. The results show that QDs are successfully embedded in polymer beads, which breaks the limitation that the conjunction of biomolecules and QDs can be achieved only for those synthesized in aqueous system. __________ Translated from Journal of Shanghai Jiaotong University, 2005, 39(1) (in Chinese)     

Structural Characterization of Anhydroicaritin Glycosides Using ESI—FT—ICR Mass Spectrometry

Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to determine the structures of anhydroicaritin glycosides by the MS/MS experiments of anhydroicaritin glycosides and their methylated derivatives,With high accuracy FT-ICR-MS provides much information about the structures of compounds ,FT-ICR-MS shows the great potential application in the structural characterization of unknown compounds.     

Solid-supported synthesis of a peptide beta-turn mimetic

[structure: see text]The solid-supported synthesis of a bicyclic diketopiperazine, a potential peptide beta-turn mimetic, is described. The Ugi reaction between the resin ester of alpha-N-Boc-diaminopropionic acid (an amine input), alpha-bromo acid, aldehyde, and isocyanide is the key step in the proposed protocol.     

Intein-mediated biotinylation of proteins and its application in a protein microarray

We report here the first example using an intein-mediated expression system to generate biotinylated proteins suitable for immobilization onto avidin-functionalized glass slides. With this novel array, proteins are site-specifically immobilized on the glass surface and are able to retain their native activity. The advantage of the avidin/biotin linkage over his-tag/Ni-NTA strategies for protein immobilization is highlighted by its ability to withstand a variety of chemical conditions, which makes this new protein array compatible with most biological assays.     

含硫希夫碱的合成研究

合成了一种含硫希夫碱—1，4-双[(2’-甲醛缩硫代氨基脲基)苯氧甲基]乙烷及其中间产物1，4-双[(2’-甲醛)苯氧甲基]乙烷．其结构经元素分析，IR和1H NMR表征。     

Reversed-phase liquid chromatography of proteins and peptides using multimodal copolymer-encapsulated silica

Multimodal copolymer-encapsulated particles for liquid chromatography were prepared by bonding 1-octadecene and unsaturated carboxylic acids on silica particles (5 microm diameter, 300 A pores) for liquid chromatography of proteins. These multimodal copolymer-encapsulated particles can provide both hydrophobic and hydrogen bonding interactions with polar compounds. The chromatographic performance of these multimodal copolymer-encapsulated particles for peptide and protein separations was evaluated under reversed-phase conditions. Compared with typical C8-bonded silica, polymer-encapsulated particles were more stable in acidic mobile phases and provided better recoveries, especially for large proteins (Mr>0.5 x 10(6)). Totally hydrophobic polymer-encapsulated particles were found to produce broad peaks for proteins, and significant improvements were observed by introducing hydrophilic groups (-COOH) onto the polymer-encapsulated surface to form a multimodal phase. For the reversed-phase liquid chromatography of peptides and proteins, improved selectivity and increased solute retention were found using the multimodal polymer-encapsulated particles. More peaks were resolved for the separation of complex peptide mixtures such as protein digests using the multimodal polymer-encapsulated particles as compared to totally hydrophobic polymer-encapsulated particles.     

A Novel Total Synthesis of (±)Shikonin

Shikonin 1 was a key component isolated from the traditional Chinese herbal medicine, Zicao(Lithospermum erythrorhizon Sieb.et Zucc), which possesses multiple biological activities1. There have been many synthetic routes to shikonin, however, all these ro…     

桑蚕丝素蛋白的结构、形态及其化学改性

通过对桑蚕吐丝机构的描述,着重从高分子科学的角度介绍桑蚕丝和蚕丝素蛋白大分子的组成、形态及各种化学、物理性质,讨论了蚕丝素蛋白的纤维化机理,并简述了丝索蛋白纤维的化学接枝改性及其应用。     

Removal of major interference sources in aqueous near-infrared spectroscopy techniques

This work describes a hybrid procedure for eliminating major interference sources in aqueous near-infrared (NIR) spectra, that include aqueous influence, noise, and systemic variations irrelevant to concentration. The scheme consists of two parts: extension of wavelet prism (WPe) and orthogonal signal correction (OSC). First, WPe is employed to remove variations due to aqueous absorbance and noise; then OSC is applied to remove systemic spectral variations irrelevant to concentration. Although water possesses strong absorption bands that overshadow and overlap the absorption bands of analytes, along with noise and systematic interference, successful calibration models can be generated by employing the method proposed here. We show that the elimination of major interference sources from the aqueous NIR spectra results in a substantial improvement in the precision of prediction, and reduces the required number of PLS components in the model. In addition, the strategy proposed here can be applied to various analytical data for quantitative purposes as well.     

Impacts of PEG-6000 pretreatment for barley (Hordeum vulgare L.) seeds on the effect of their mature embryo in vitro culture and primary investigation on its physiological mechanism

In this paper, we studied polyetheneglycol (PEG) pretreatment effect on the mature embryo culture in vitro by using barley (Hordeum vulgare L.) seeds. Meanwhile, we analyzed and assayed its mineral element and endogenous hormone level. The experimental results were as follows: (1) PEG-6000 imbibition could obviously slow down the water timecourse absorbed by barley seeds; (2) 10% PEG-6000 treatment of barley seeds for 3 h had a positive effect on germination in vitro and callus induction of the barley seed mature embryos; (3) 10% PEG-6000 treatment inhibited soluble leakage from the seeds; (4) N leakage was mainly from the endosperms, Mn2+ leakage from embryos; (5) PEG-6000 treatment changed greatly the hormone level (ABA, IAA, GAs), which influenced the percentage of plantlets from the mature embryo callus. The results can provide some clues to scientific sowing of crop seeds, pretreatment for the purpose of uniform seedlings, and the explant response quality in plant tissue culture.