PHASE-SEPARATION IN ANHYDRIDE-CURED EPOXY-RESIN CONTAINING PHENOLPHTHALEIN POLY(ETHER ETHER KETONE)

Dynamic mechanical analysis and scanning electron microscopy were used to study phase separation of three blends of anhydride-cure bisphenol-A-type epoxy resin with phenolphthalein poly(ether ether ketone). Phase separation was observed for all the blends. The overall compatibility and the resulting morphology of the cured blends are dependent on the choice of cure agent. The phenomena have been discussed from the points of view of both thermodynamics and kinetics. The effects of the choice of hardener on phase separation are considered to be primarily due to differences between the chemical natures of the hardeners.

PEO/PVP共混体系结晶行为

本文用WAXD、PLM、DSC方法研究了聚氧化乙烯(PEO)/聚乙烯基吡咯烷酮(PVP)共混体系的结晶行为,探索了两组分聚合物间相互作用及体系结晶度与非晶组分含量的关系。DSC研究表明PEO/PVP共混体系具有两个玻璃化转变温度,分别是纯组分的T_g,无相容性。应用Avrami和LH方程对其动力学参数进行了研究。偏光显微镜观察了共混物结构形态。

CHARACTERIZATION OF GAMMA-IRRADIATED CRYSTALLINE POLYMER .3. THERMAL-BEHAVIOR OF GAMMA-IRRADIATED POLYAMIDE-1010

Thermal behaviour of gamma-irradiated plain PA1010 and PA1010 containing different amounts of difunctional cross-linking agent BMI was investigated. In DSC endo- and exotherm, it was found that during irradiation, the presence of BMI markedly changes the melting and crystallisation characteristics of PA1010. A supposition that the network of BMI-containing specimens is rather loose in structure was proposed to explain the discrepancy in thermal behaviour between these two kinds of specimens. The supposition was further ascertained by the less brittleness in mechanical property of specimens containing BMI. Besides, the complexity of the thermal behaviour of gamma-irradiated PA1010 was discussed and attributed mainly to the increase in sigma-e, the fold surface free energy of chain fold crystals.

CHARACTERIZATION OF GAMMA-RADIATION CROSS-LINKED CRYSTALLINE POLYMERS BY CRYSTALLIZATION TEMPERATURE

The effect of gamma-radlatlon on plain crystalline polymers and crystalline polymers containing different amounts of difunctional monomer both in vacuum and in air at room temperature has been investigated with DSC. It was found that the crystallization temperature T_c of crosslinked sample measured on DSC at a constant cooling rate decreases with increasing radiation dose. The difference between T_c before and after crosslinking (T_(c_0)-T_(c_R)) is linearly related to the radiation dose for plain polymer....

葡萄糖酸锗对大白鼠内分泌腺的影响

应用放射免疫法及透射电镜研究葡萄糖酸锗对雌性大白鼠内分泌腺的影响。大鼠经腹腔注射葡萄糖酸锗50mg/kg·d,连续6天,放免测定血清的激素值,实验组的生长激素(GH)显著增高(P<0.01),促甲状腺激素(TSH)、三碘甲状腺原氨酸(T_3)和四碘甲状腺原氨酸(T_4)均显著降低(P<0.01),而卵泡刺激素(FSH)、黄体生成素(LH)和皮质醇均无明显变化。透射电镜下可见脑垂体远侧部生长激素细胞,呈分泌释放功能旺盛相。促甲状腺激素细胞呈分泌释放功能不活跃状态。结果表明,葡萄糖酸锗具有刺激生长激素细胞的分泌和抑制促甲状腺激素细胞和甲状腺滤泡上皮细胞的分泌。

氯化钐对雌性大白鼠内分泌腺结构和功能的影响

实验通过血清激素测定和透射电镜观察相结合,研究氯化钐对雌性Wistar大白鼠内分泌腺结构和功能的影响,发现连续三天每天经腹腔给予大白鼠SmCl_3 80mg/kg·bw后,第六天大鼠血清中GH水平明显升高(P<0.01),而T_4水平显著下降(P<0.01);FSH、LH、TSH、T_3和皮质醇的血清浓度与对照组相比无明显改变。电镜下观察到生长激素细胞粗面内质网扩张,分泌颗粒减少,甲状腺滤泡上皮细胞核固缩,粗面内质网高度扩张呈病理性改变。实验结果表明,一定剂量的SmCl_3具有促进生长激素细胞分泌,使血清生长激素水平升高和损伤甲状腺滤泡上皮细胞,使血清T_4水平降低的作用。

氯化钐对冷束缚应激大鼠血清激素的影响及其抗应激作用

研究了氯化钐对冷束缚应激大鼠血清激素的影响及其抗应激作用。用放射免疫法测定了血清GH、FSH、LH、TSH、T_3、T_4和皮质醇浓度,并用光镜和透射电镜观察了胃粘膜和脑垂体促肾上腺皮质激素细胞及肾上腺皮质束状带细胞超微结构的变化。结果表明,在应激反应中,氯化钐具有明显的提高血清GH和TSH值(p<0.01),显著降低血清FSH、T_4和皮质醇值(p<0.01),抑制促肾上腺皮质激素细胞分泌和保护胃粘膜的作用。

HREM IMAGING OF POLY(ARYL-ETHER-KETONE) CRYSTAL

High resolution transmission electron microscope (HREM) was used to observe the rigid chain polymer poly(aryl-ether-ketone) (PEK), so as to study the morphology of the crystals and molecular arrangement within a crystal.Many kinds of material crystal structures have been studied with HREM in recent years. So far as polymeric materials are concerned, the application of HREM

A New Cadinane Sesquiterpene from the Marine Brown Alga Dictyopteris divaricata

A sample of the marine brown alga D. divaricata collected off the coast of Yantai (P. R. China) was dried, powdered, and extracted with the mixture of CHCl3 and MeOH (1: 1, v/v). By a combination of silica gel and Sephadex LH-20 column chromatography and preparative TLC, a new cadinane sesquiterpene 1,4-epoxymuurolan-5 beta-ol (1) was isolated from this species. Its structure was established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

Comparison of two marine sponge-associated Penicillium strains DQ25 and SC10: differences in secondary metabolites and their bioactivities

Two strains of Penicillium, DQ25 and SC10, isolated from marine sponge Haliclona angulata (Bowerbank) and Hymeniacidon sp. respectively, were subjected to stationary cultivation under GYP medium for 30 days. The fermentation extracts were undergone bioactivities assays against human pathogens, phytopathogenic fungi and brine shrimp (Artemia salina). Bioassays-guided compounds isolation was performed by Silica gel columns and Sephadex LH-20 chromatography. Spectroscopic methods were used to structures elucidation of the compounds. Results showed the activities of secondary metabolites of strain DQ25 were generally stronger than that of strain SC10. Major bioactive molecules isolated from strain DQ25 were a 1,4-naphthoquinone derivative and an unidentified alkaloid. The two components were not isolated from the extract of strain SC10. ITS sequences revealed that these two species have the greatest similarity with Penicillium vinaceum and Penicillium granulatum respectively.

cDNA cloning and mRNA expression of the translationally controlled tumor protein (TCTP) gene from Japanese sea perch (Lateolabrax japonicus)

A homologue of the lower vertebrates translationally controlled tumor protein (TCTP) was cloned from the marine fish Japanese sea perch (Lateolabrax japonicus) by the technology of homology cloning. The full-length cDNA sequence of the sea perch TCTP gene contained a 5' untranslated region (UTR) of 47 bp, a 3' UTR of 433 bp, and a putative open reading frame (ORF) of 510 bp encoding a polypeptide of 170 amino acids. The deduced amino acid sequence of the sea perch TCTP gene showed a high similarity to that of zebrafish, rohu, rabbit, chicken and human. Sequence analysis revealed there were a signature sequence of TCTP family, an N-glycosylation site, and five Casein kinase phosphorylation sites in the sea perch TCTP. The temporal expression of TCTP genes in healthy and lipopolysaccharide (LPS) challenged fishes was measured by semi-quantitative reverse transcription-PCR (RT-PCR). The results indicated that LPS could up-regulate the expression of sea perch TCTP in the examined tissues, including head-kidney, spleen and liver.