超临界流体技术在制备药物输送系统中的应用

超临界流体技术以其特有的优点成为引人注目的制备药物细微粒子及控制释放的药物输送系统的方法。本文介绍了超临界流体沉淀技术的概念、进展及相关的应用。     

磺化丁基橡胶离聚体在混合溶剂中的聚集行为

用顺磁共振（ESR）谱和粘度法考察了磺化丁基橡胶离聚体在二甲苯／正己醇混合溶剂中的聚集行为．ESR谱表明离聚体的离子基团发生聚集，其聚集程度受极性共溶剂（正己醇）的影响．粘度考察表明，在不同的浓度时离子基团有不同的聚集形式，低浓度时以分子内聚集为主，高浓度时以分子间聚集为主．离聚体的聚集度（DA）与浓度（c）的关系可用经验式DA＝Aexp（kc2）表示，其中A、k为常数．k值反映聚集度受浓度影响的程度，醇含量增大时k值减小，这是因为醇对离子的溶剂化作用导致离子聚集的倾向减小．     

Stereochemical control of Zn(II)/Cu(II) selectivity in piperidine tripod ligands

Stereochemistry plays a major role in the selectivity toward zinc ion over copper(II) of some tripodal ligands with a central piperidine scaffold, one of which acts as a fluorescent zinc sensor with nanomolar sensitivity.     

Neuroprotective glucosides of magnolol and honokiol from microbial-specific glycosylation

Thirteen new glucosides (1–13) of magnolol and honokiol were obtained from specific O-glycosylation by two filamentous fungi, Cunninghamella echinulata AS 3.3400 and Rhizopus japonicus ZW-4. The glucosides' structures were determined on the basis of extensive spectroscopic (HRESIMS, 1D and 2D NMR, and CD) analyses and a chemical method. C. echinulata appeared to transfer a glucosyl moiety to 2-OH of magnolol and honokiol, whereas R. japonicus preferred to regio-specifically transfer a glucosyl moiety to 4′-OH when honokiol was as the substrate. In addition, hydroxylation by C. echinulata and specific 6″-O-acylation of the introduced glucosyl moiety by R. japonicus were observed as minor reactions. Bioassay results indicated that glucosides 1–12 together with magnolol and honokiol at 10 μM attenuated the glutamate-induced toxicity in SK-N-SH cells to levels comparable to the results for MK-801, a positive control. However, the water-solubility of major glucosylated products (1, 8, and 11) increased greatly.     

Coumarin Sulfonamides and Amides Derivatives: Design,Synthesis, and Antitumor Activity In Vitro

Coumarins possesses immeasurable antitumor potential with minimum side effects depending on the substitutions on the basic nucleus, which exhibits great prospects for antitumor drug development. In an attempt to develop novel antitumor candidates, a series of coumarin sulfonamides and amides derivatives were designed and synthetized. The majority of these derivatives showed good cytotoxic activity against MDA-MB-231 and KB cell lines, among which compound 9c was the most potent against MDA-MB-231 cells, with IC₅₀ value of 9.33 μM, comparable to 5-fluorouracil. Further investigation revealed that compound 9c had versatile properties against tumors, including inhibition of cell migration and invasion as well as inducing apoptosis. Reactive oxygen species (ROS) assay and western blotting analysis suggested that compound 9c promoted cancer cell apoptosis by increasing ROS levels and upregulating the expression of caspase-3 in MDA-MB-231 cells. These results indicated that compound 9c could be promising lead compound for further antitumor drug research.     

Effects of Saline-Alkaline Stress on Seed Germination and Seedling Growth of Sorghum bicolor (L.) Moench

In order to study the adaptation ability of sweet sorghum (Sorghum bicolor L. Moench) in the Yellow River Delta, the sweet sorghum variety Mart was used in this study to determine the roles of different saline-alkaline ratio stress treatment during seed germination to seedling stage. The results showed that Na⁺ concentration had a significant impact on the seed germination, seedling growth, and plant survival of sweet sorghum. Increasing Na⁺ concentration led to a decline in germination rate, final germination percentage, survival percentage, plant height, and dry weight per plant, a prolonged mean time of germination, as well as loss of improvement effect of low-Na+ concentration. The interaction effect of Na⁺ concentration and pH on the mean time of germination and germination rate was not significant (p?+ concentration (100 mM), high pH reduced the mean time of germination and increased the germination rate, without decline in final germination percentage and survival percentage. Therefore, at least in the duration of seed germination to the harvest period in the research, the sweet sorghum was resistant to the pH stress (≥9.04) when the Na⁺ concentration was below 100 mM. When suffered from the saline-alkaline stress, the seedling of sweet sorghum was characterized by ecological adaptive features, such as decreased stem ratio and chlorophyll b content in leaves and increased root ratio and chlorophyll a content, in order to maintain the uptakes of water and nutrient, and carbon assimilation. When the stress intensified, the lipid oxidation products, e.g., malondialdehyde (MDA), increased in sweet sorghum seedlings. However, the increasing of soluble protein content and antioxidant enzyme activity (superoxide dismutase (SOD), guaiacol peroxidase (POD), and gatalase (CAT)) was only founded in neutral low-Na⁺ concentration treatment (A₁), which indicated that high-salt concentration and pH all elicited harmful effects and limited the self-healing ability of sweet sorghum seedlings. In all, in order to grow sweet sorghum in the saline-alkaline soils of the Yellow River Delta, the salt concentration and pH value of the soil must be taken into consideration, and seeding density should be increased and supported by appropriate irrigation measures to reduce saline-alkaline stress so as to ensure the survival and growth of sweet sorghum seedlings.     

不同色浆质量分数的水性聚氨酯涂料对聚氯乙烯表皮低温爆破性能的影响

本文制备了一系列不同色浆质量分数的水性聚氨酯涂料,并将其喷涂在汽车仪表板聚氯乙烯(PVC)表皮的背面形成复合材料。 用旋转流变仪表征了涂料的粘度以评价其喷涂性能;用差示扫描量热仪表征了材料的玻璃化转变温度(T_g);利用万能材料试验机表征了材料在-30 ℃条件下的拉伸性能及抗撕裂性能;用动态热机械分析仪表征了材料的损耗比随温度的变化。 结果表明:不同色浆质量分数的涂料都能喷涂,含有涂层材料PVC表皮在-30 ℃低温爆破性能与涂层材料的T_g、低温拉伸性能、抗撕裂性能的关系并不大,而与涂层材料的阻尼性能直接相关。 材料的阻尼性能越好,其低温爆破性能越好。     

Harmonically pump a femtosecond optical parametric oscillator to 1.13 GHz by a femtosecond 515 nm laser

We demonstrate a harmonically pumped femtosecond optical parametric oscillator(OPO)laser using a frequency-doubled mode-locked Yb:KGW laser at a repetition rate of 75.5 MHz as the pump laser.Based on a bismuth borate nonlinear crystal,repetition rates up to 1.13 GHz are realized,which is 15 times that of the pump laser.The signal wavelength is tunable from 700 nm to 887 nm.The maximum power of the signal is 207 m W at the central wavelength of 750 nm and the shortest pulse duration is 117 fs at 780 nm.The beam quality(M^2 factor)in the horizontal and vertical directions of the output beam are 1.077 and 1.141,respectively.