广泛联合探讨合作共商发展——第二届中国项目管理国际会议ICPM2004闭幕讲话（摘要）

"第二届中国项目管理国际会议"汇聚了来自国内外有关政府部门和机构、企业界、金融界、教育界、学术界、中介组织以及新闻媒体方面的朋友们,围绕"投资与项目管理科学化、国际化"这个主题,共同总结两年来中国项目管理实践的经验,深入学习和交流国外最前沿项目管理理论、方法和技术,寻求和加强国际企业间与区域性合作的投资与项目管理科学化、国际化,研讨我国投融资管理体制和国有资产管理体制两项重大改革带来的中国经济发展和国内外企业投资的新模式与新机遇.近80名包括高层主管领导在内的国内外专家,结合当今国际经济与项目管理的发展,以及项目管理应用的典型案例做了精彩的演讲.同时,介绍了<中国项目管理知识体系纲要>的修订情况,研讨了发起中华区域项目管理促进会的有关事宜,全面推进中国投资与项目管理科学化、国际化,不失时机地将中国项目管理发展又推进到了一个新的里程碑.这次大会还为与会代表们提供了一个结交朋友、探讨合作、共商发展的机会.大会开得很成功.

Phytochemical Profile and <i>In Vitro</i>Antioxidant Properties of Essential Oils from Powder Fractions of <i>Eucalyptus camaldulensis</i>Leaves

Dried leaves of Eucalyptus camaldulensis were finely grinded and fractionated by sieving into four granulometric classes (<100 μm, 100 - 200 μm, 200 - 355 μm and >355 μm). The obtained powder fractions were used for essential oil (EO) extraction by hydrodistillation and their phytochemical profile and in vitro antioxidant activities were evaluated. The mother powder (unsieved powder) was used for comparison. Particle size exerted a significant influence (p < 0.05) on the phytochemical composition and in vitro antioxidant properties of the EOs. Comparatively, the mother powder had the highest contents of α-pinene (55.6%), camphene (3.4%) and limonene (3.7%), while 1,8-cineole (26.6% and 22.4%), exo-fenchol (5.6% and 3.5%), α-campholenol (4.2% and 3.4%), L-trans-pinocarveol (5.5% and 2.7%), L-borneol (12.6% and 6.8%) and α-terpineol (16.4% and 7.6%) are the main compounds of EOs from the <100 μm and 100 - 200 μm fractions, respectively. The antioxidant activities of the EOs revealed higher radical-scavenging activities DPPH (90.62% and 70.46%) and ABTS (89.59% and 73.31%) for finer fractions (<100 μm and 100 - 200 μm, respectively). The best reducing power (36.15% and 34.27%) were also found in these finer powder fractions which improved by more than 2 times the value of mother powder (reducing power of 17.01%). These results suggest that grinding followed by sieve fractionation concentrates the majority of antioxidant phytochemicals in the EOs of the finer powder fractions of E. camaldulensis leaves. Finer powders could be used as functional ingredients in food formulations for the management of chronic diseases.

Particle Size Effects on Antioxydant and Hepatoprotective Potential of Essential Oil from Eucalyptus camaldulensis Leaves against Carbon Tetrachloride-Induced Hepatotoxicity in Rats

Particle size fractionation by sieving is used to optimize antioxydant potential of natural substances. The aim of the present study was to evaluate particle size effects on antioxidant and hepatoprotective potential of Eucalyptus camaldulensis essential oils (EO) on CCl4-induced hepatic damage in Wistar rats. Animals were daily orally treated with the EOs extracted by hydrodistillation from powder sieved at four particle sizes (≥355, 200 - 355, 100 - 200, ≤100 μm) and those of the unsieved powder at dose of 50 mg/Kg for 7 days. Compounds that are evaluated for these activities are hydrocarbons and oxygenated terpenes that were identified and quantified by GC/MS. Activities of enzymes markers of hepatocellular damage in serum and antioxidant enzymes in the liver homogenates were measured. In this research, EOs significantly prevented the increase in serum ALT and AST (p < 0.05), total cholesterol, triglyceride and LDL-cholesterol level in acute liver damage induced by CCl4 and significant increase level of plasma HDL-cholesterol. Also, significantly (p < 0.05) decreased the extent of malondialdehyde (MDA) formation and elevated the activities of superoxide dismutase (SOD) and catalase (CAT) liver in comparison to negative control group. The best antioxidant and hepatoprotective activities were those of EOs from two fine powder fractions (≤100 μm and 100 - 200 μm) was correlated to their high concentration in oxygenated terpenes (70.9% and 46.4%, respectively), when compared to the large particles (200 - 355 μm and ≥355 μm, with 33.3% and 41.8%, respectively) and unsieved powder (37.4%).

STIFFNESS AND EXCLUDED VOLUME EFFECTS ON CONFORMATION AND DYNAMICS OF POLYMERS:A SIMULATION STUDY

This work investigates the effects of the excluded volume and especially those of the chain stiffness on the structural and dynamical properties of a model polymer chain. The theoretical framework is the same as in the recent works by Steinhauser et al., where a Rouse approach is adopted. Our model differs in that our chains have a finite average bending angle. As in the works by Steinhauser et al., Langevin dynamic simulations were performed without hydrodynamic interactions. Whereas this doesn＇t impact the static properties we obtain, it also allows us to compare our results on dynamic properties to those predicted by Rouse theory, where hydrodynamic interactions are also neglected. Our results show that the structural properties are very sensitive to the chain stiffness, whereas the dynamic scaling laws remain the same as those by Rouse theory, with the prefactor depending on the persistence length.