C9‐Iridoids from Scrophularia buergeriana

Four new iridoids, buergerinins B–E ( 1 – 4 ), along with three known iridoids, were isolated from the roots of Scrophularia buergeriana. Their structures were identified on the basis of spectroscopic analysis.     

SILICA-BOUND CROWN ETHERS PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefms with triethoxysilane in the temperature range of 60 to 130 ℃.     

配位聚合物{[CoL][FeⅡFeⅢ(ox)3·1.5H2O]}∞的合成、波谱表征和磁学性质

A new Schiff base complex， CoL(ClO₄)·3H₂O (1) {L represents condensed from equal molar ratio of sali-cylaldehyde and diethylenetriamine} was synthesized and characterized. Further， a new coordination polymer， {[CoL][Fe^ⅡFe^Ⅲ(ox)₃·1.5H₂O]}_∞ (2)， was synthesized and characterized， where ox^2-=oxalate. The results of the IR and M?ssbauer spectra of 2 revealed that the coordination polymer exists 2-D layer structure in the solid state， and anions layer was formed by [^ⅡFe^Ⅲ(ox)₃]^- unit. The magnetic properties of 2 have been measured and the results indicate that there is magnetic ordering in the low temperature， which may arise from intermolecular ferromagnetic interactions or spin canted effects.     

配位聚合物{[MnL][FeⅡFeⅢ(ox)3·1.5H2O]}∞的合成及其磁学性质

合成和表征了一种新的Schiff碱配合物MnL(ClO4)*3H2O(1)(其中L为n(水杨醛)∶n(二乙撑三胺)=1∶1缩合而成的Schiff碱).1与FeSO4*7H2O和K3[Fe(ox)3]*3H2O(ox=oxalate)进一步反应,生成了双金属层状配位聚合物{[MnL][FeⅡFeⅢ(ox)3]*1.5H2O}∞(2).IR和Mssbauer谱测定结果表明,2具有二维层状结构,其阴离子层由[FeⅡFeⅢ(ox)3]-单元构成.变温磁化率(5K～100K)测试结果表明,2中的自旋载体之间存在反铁磁交换作用.5K时的磁滞现象表明2在低温时可能存在铁磁有序,这可能是亚铁磁或自旋倾斜造成的.     

A simulation of thermal characteristic parameters with an inverse “S” type curve

A synthetical equation is proposed to characterize the essential features of the inverse “S” type curve on the basis of summing-up simulation approach of “S” type curve. The two physical variables in the model obtained are discussed and the detailed method used to determine the parameters is given. The model is then presented to describe the crystallization of poly(caryleher ether ketone) (PEEK) and thermal decomposition of poly(amide-imide) (PAI) respectively. It is found that some thermal characteristic parameters can be well estimated from the model simu-lated in computer.     

Two-dimensional protein database of human pancreas

We report here the two-dimensional protein database of human pancreas. The proteins were analyzed by two-dimensional electrophoresis followed by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Totally, 302 proteins were identified, of which about 27% were enzymes with a broad range of catalytic activities. Several of these are specifically expressed in pancreas, such as pancreatic amylase, pancreatic stone protein, pancreatitis-associated protein, pancreatic lipase, pancreatic elastase, etc. Structural and cytoskeletal proteins are also strongly represented on the gels. Thus, the pancreatic proteome reflects the organ's function. This work paves the way for further studies on pancreatic protein expression in health and disease, such as diabetes and pancreatic cancer.     

超临界二氧化碳介质中钯催化炔烃羰基化反应

研究了以超临界二氧化碳为反应介质实现改善钯催化炔烃羰基化反应绿色性的方法 .研究结果表明 :醇的用量、二氧化碳压力和反应温度等因素均对钯催化炔烃羰基化反应的化学选择性均有影响 ,即存在炔烃的羰基化反应与氧化偶合反应的竞争     

Surface modification studies of edge-oriented molybdenum sulfide nanosheets

We have synthesized edge-oriented MoS2 nanosheets by the evaporation of a single source precursor based on Mo(IV)-tetrakis(diethylaminodithiocarbomato). The surface chemistry of the MoS2 nanosheets has been studied in order to evaluate the chemical reactivities of the basal planes and edges. By irradiating the MoS2 nanosheet with a scanning infrared laser, micron-scale lithographical structures can be created due to laser-induced oxidation of MoS2 to form nanocrystalline MoO3. Preferential reactivities of the MoS2 basal edges in an electrochemical environment and during vapor phase deposition have been demonstrated. Functionalization of the basal plane with 1-pyrene acetic acid allows the immobilization of DNA and immunoglobins on the MoS2 basal plane.     

An evaluation of exogenous application of protoporphyrin IX and its dimethyl ester as a photodynamic diagnostic agent in poorly differentiated human nasopharyngeal carcinoma

5-Aminolevulinic acid and its esterified analogues have been under much investigation to enhance the endogenous production of protoporphyrin IX (PpIX) in tumor cells. However, in this work, we studied the in vitro and in vivo efficacy of exogenously administered PpIX and its esterified analogue, PpIX dimethyl ester (PME), in poorly differentiated human nasopharyngeal carcinoma (NPC/CNE-2) as a photodynamic diagnostic (PDD) agent. NPC/CNE-2 at its earliest time, 1 h after incubation with PME in in vitro studies, has exhibited 64% (P <0.01) higher tumor to normal cell (T/N) fluorescence ratio than with PpIX. In an in vivo mouse xenograft model, comparable photosensitizer concentration in tumor after intravenous administration was observed at 1-3 h time points, but at 9 h, PME had 31% (P=0.05) greater concentration in tumor compared with PpIX. In addition, by constituting PME and PpIX in different topical gel composites, of which, PME gel composition of 8:2 Plasdone and Gantrez resulted in the highest T/N ratio at 6 h after application (34%; P <0.05) in comparison with other gel composites. Evaluation of PME and PpIX constituted in the delivery vehicles investigated showed comparable selectivity for tumor at 1-3 h, thus neither photosensitizer is more efficient than the other for PDD at the early time points; however, beyond 6 h, PME had higher selectivity for tumor compared with PpIX. Thus, further investigation is warranted to improve the drug delivery vehicle for greater tumor selectivity at a shorter incubation time.     

Simultaneous quantification of differently glycosylated, acetylated, and 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one-conjugated soyasaponins using reversed-phase high-performance liquid chromatography with evaporative light scattering detection

A novel method utilizing high-performance liquid chromatography (HPLC) with evaporative light scattering detection (ELSD) and electrospray ionisation mass spectrometry (ESI-MS) was developed for the analysis of soyasaponins, a divers group of triterpenic compounds with one or two sugar side chains, occurring in soy. Group A soyasaponins in different degrees of acetylation, as well as group B soyasaponins in both their 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated and non-conjugated forms could be separated and quantified using authentic soyasaponin standards, in one single run. The method was tested by the determination of the soyasaponin content and composition of eight soygerm samples of different origin. Differences in the composition and the degree of acetylation of the group A soyasaponins were observed among these samples. The group B soyasaponins showed much less variability and they were mainly present in their DDMP-conjugated form.