Microspheres of essential oil in polylactic acid and poly(methyl methacrylate) matrices and their blends

This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.

The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same.     

鱼油抗大鼠动脉粥样硬化的实验研究

以大鼠高脂血症及动脉粥样硬化模型观察鱼油的作用，并与舒降之、诺衡比较。鱼油组血清总胆固醇（ＴＣ）、甘油三酯（ＴＧ）、低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）及ＬＤＬ－Ｃ／ＴＣ显著低于高脂组（均为Ｐ＜０．０１）；生化与病理检查提示鱼油能防止肝内脂质沉积，减少肝组织脂质过氧化物水平；鱼油能明显抑制高脂饮食造成的早期动脉粥样硬化病变。鱼油降ＴＧ的作用与舒降之及诺衡无明显差异，降ＴＣ的效果优于诺衡（Ｐ＜０．０５），改变脂蛋白成分的作用不及舒降之与诺衡。研究表明鱼油能延缓大鼠高脂血症和动脉粥样硬化的发生与发展。     

Mortality studies of machining fluid exposure in the automobile industry III: A case-control study of larynx cancer

A case-control study of larynx cancer was conducted within a cohort of automobile workers exposed to metal working fluids, commonly referred to as machining fluids (MF). Results are based on 108 cases of larynx cancer and 5:1 matched controls. Risks associated with specific types of MF, as well as specific components of the fluids were evaluated. Based on a retrospective exposure assessment, lifetime exposures to straight and soluble fluids, grinding particulate, biocides, selected metals, sulfur, and chlorine were examined. Exposure to asbestos and acid mists at two of the three study sites was also characterized. Results suggest that straight mineral oils are associated with almost a two-fold excess in larynx cancer risk. There was also evidence of an association with elemental sulfur, commonly added to straight MF to improve the integrity of the materials under extreme pressure and heat. It is not clear whether sulfur is causally related to an excess relative risk of larynx cancer or whether the observed association is the result of unmeasured confounding by another contaminant or process feature. For example, the high stress operations that require MF enriched with sulfur are also more likely to produce polycyclic aromatic hydrocarbons (PAHs) during the process. Thus, the observed association with sulfur may be due to an association with PAH. The finding of excess risk of laryngeal cancer associated with MF is consistent with several previous reports in the literature. This is the first study, however, to distinguish straight mineral oils from other types of MF. Based on these findings, a general reduction in concentrations of straight mineral oil particulate in occupational environments would be prudent.     

润滑油抗泡机理的研究 Ⅱ.助泡剂对泡沫倾向的影响及抗泡剂配伍性能

考察了各类添加剂在不同浓度、温度及不同基础油中的泡沫倾向,并测定了这些条件下体系的表面张力。从表面化学角度解释了添加剂对泡沫性质的影响,并通过对抗泡剂配伍性能的研究,验证了消泡机制:抗泡剂须具备高的表面活性才能吸附于泡膜表面,降低泡膜的表面粘弹性,改变膜的流变性能,从而起消泡作用。     

珠子参挥发油的化学成份

利用气相色谱—质谱—计算机联用仪分析了云南省腾冲县产珠子参挥发油的成份,从中鉴定了27种化合物,测定了它们的相对含量,其中有10种倍半萜烯和一种倍半萜醇。     

Occupational irritant contact dermatitis and fungal infection in construction workers

We have examined 6 construction workers who developed chronic skin diseases on their hands over a period of 15 years (1970–1985). 4 developed a Trichophyton rubrum infection, and the other 2 an irritant contact dermatitis. All of them carried out jobs which caused traumatization of the skin, due to the presence of ethylene glycol and mineral oils during operation of pneumatic hammers in winter. They also suffered other types of skin trauma during their work. Construction workers may be at risk of developing an occupational skin disease involving fungal infection.     

Screening of the antiradical action of vegetable oils

Information on radical scavenging activity (RSA) and antioxidant potential of vegetable oils are not reported, or reporting has been rather limited. Such data is of importance for the evaluation of nutritional and health impact of these oils. The main objective of this short study was to compare the antiradical performance of some common and unusual vegetable oils. The described arrangement for our simple experiment uses the addition of stable radicals 1,1-diphenyl-2-picrylhydrazyl (DPPH) to vegetable oils, which are decomposed by components having antioxidant properties. The order of effectiveness of oils in inhibiting free radicals was as follows: coriander>blackcumin>cottonseed>peanut>sunflower>walnut>hemp seed>linseed>olive>niger seed. This initial survey might serve as a springboard for future research into this area.     

高良姜根茎叶挥发油化学成分的比较

采用ＧＣ－ＭＳ－计算机联用技术从高良姜根、茎叶挥发油中分别鉴定出２４、２１和１６种化学成分，其中有１３种成分为３个部位所共有。但根、茎、叶的含油量及同一成分在不同部位的含量差异较大。     

玻璃体切割手术对角膜内皮细胞的影响

目的 观察玻璃体切割手术对角膜内皮细胞影响的相关因素。 方法 回顾分析21 3例玻璃体切割手术患者213只眼手术前及手术后1周、1、3个月时角膜内皮镜检查结果。其中单纯玻璃体切割手术78只眼，玻璃体切割手术联合白内障摘除手术135只眼；硅油填充34只眼，C³F⁸填充53只眼，无眼内填充物者126只眼。 结果 单纯玻璃体切割组、玻璃体切割联合白内障摘除后囊完整组手术前后不同时期角膜内皮细胞数差异无显著性的意义（P均>0.05）；无后囊且眼内填充C³F⁸或硅油组手术后较手术前角膜内皮细胞数明显减少，其差异有显著性的意义（P<0.05）。 结论 玻璃体切割联合白内障摘除且晶状体后囊不完整者，眼内填充C³F⁸或硅油对角膜内皮细胞有一定的损伤作用。（中华眼底病杂志，2004，20：101-103）     

金佛手挥发油化学成分的GC-MS分析

目的:分析金佛手鲜品与干品挥发油的化学成分与相对含量。方法:用色谱-质谱联用法(GC-MS)测定佛手挥发油,结果用计算机检索NIST98数据库。结果:从佛手挥发油中检测出30多种化学成分,主要成分是D-柠檬烯和( )-2-蒈烯,鲜品挥发油中分别为40.02％、21.35％,干品挥发油中分别为38.63％、18.17％。结论:金佛手挥发油的主要成分是柠檬烯与蒈烯。