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1.
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. 相似文献
2.
A. Heinig S. H. Heywang-Köbrunner P. Viehweg D. Lampe J. Buchmann R. P. Spielmann 《Der Radiologe》1997,37(9):710-717
Summary
Early recognition of recurrence and work-up of clinically indeterminate lesions may be impaired after reconstruction with
silicone implants due to superimposition of the implant or to scarring. This study was undertaken to evaluate the use of contrast-enhanced
MRI in patients with silicone implant after breast cancer. Contrast-enhanded MRI was offered to 169 patients. Comparative
two- to three-view mammography was also performed in 169 patients, as well as comparative sonography in 144 patients. Conventional
imaging and clinical examination detected only 8/13 recurrences, whereas 12/13 were detected by MRI. One recurrence had been
visible as a strongly enhancing 2-mm dot in a previous examination (2 years before), but was not called. It was therefore
counted as false negative. In addition, multicentricity was detected by MRI alone in two of three cases. MRI correctly diagnosed
scar tissue in all cases with indeterminate findings. However, due to false-positive calls caused by enhancing granulomas
specificity could not be improved. Contrast-enhanded MRI allowed decisive additional information in our study group and improved
the sensitivity significantly (concerning all diagnoses). Contrast-enhanded MRI is recommended in patients with diagnostic
problems or high risk of recurrence after silicone implants.
相似文献
3.
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。 相似文献
4.
维甲酸硅油的视网膜毒性实验研究 总被引:1,自引:0,他引:1
目的:了解维甲酸硅油对视网膜是否产生毒性。
方法:12只新西兰白兔的24只眼,随机分为3组,行气体压迫玻璃体手术3天后,分别向玻璃体腔内注入硅油(4只眼)、5μg/ml维甲酸硅油(10只眼)、10μg/ml维甲酸硅油(10只眼)各
0.5m1,用检眼镜、光漳和电镜检查来观察视网膜变化情况。
结果:注入硅油28天后,未发现各浓度的维甲酸硅油对视网膜产生毒性作用。结论:浓度为5、10μg/ml的维甲酸硅油注入玻璃体腔4周,对视网膜不产生毒性作用。
(中华眼底病杂志,1997,13:81-82) 相似文献
5.
G. Gherardini R. Zaccheddu S. M. Milner M. El-Shazlyl I. Liapakis 《European journal of plastic surgery》2006,29(1):9-12
Breast augmentation is one of the most frequently performed cosmetic surgery procedures worldwide. We report on a series of 502 consecutive cosmetic breast augmentations by a single surgeon, using both the submuscular and submammary approaches. A vacuum drain was placed in the surgical pocket at the end of the procedure. The drain fluid collection was recorded immediately after the surgery and the following day before removal. A tenfold increase in the amount of fluid collection was noted in the drain’s reservoir. Thirteen patients presented with minor wound healing problems at the second postoperative follow-up, which were treated conservatively; two of them had the implant removed and replaced after 2 months. There were only two capsular contractions at 1-year follow-up. We focus our discussion on the drainage in the early postoperative period and conclude that the routine use of a surgical drainage reduces the risk for complications. Based on our findings, we advocate that short-term routine use of a surgical drain is advisable. 相似文献
6.
Chest Wall Implants: Their Use for Pectus Excavatum,Pectoralis Muscle Tears,Poland's Syndrome,and Muscular Insufficiency 总被引:3,自引:3,他引:0
Darryl J. Hodgkinson 《Aesthetic plastic surgery》1997,21(1):7-15
Solid customized and prefabricated silicone implants have been used by the author for 15 years in a wide range of chest wall
deformities. Chest wall implants are often used in males seeking to augment a muscularly deficient or underdeveloped chest;
however, their greatest use has come in a variety of deformities both congenital and acquired, such as pectus excavatum, Poland's
Syndrome, and pectoralis muscle tears. The implants can be either customized using a moulage technique or are prefabricated,
manufactured implants which can be modified on the operating table to repair the contour deformity. The immediate postoperative
problem of seroma and subcutaneous implant ``show' has been minimized by careful planning, gentle technique, deep insertion,
improved patient positioning on the operating room table, and the use of oral anti-inflammatory medications. The long-term
results of these implants seem very satisfactory. The patients are usualy physically active, and the implants show no long-term
sequelae such as seroma, infection, displacement, or rupture. 相似文献
7.
Ellen A. Eisen Paige E. Tolbert Marilyn F. Hallock Richard R. Monson Thomas J. Smith Susan R. Woskie 《American journal of industrial medicine》1994,26(2):185-202
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. 相似文献
8.
9.
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。 相似文献
10.
P. E. K. Donaldson 《Medical & biological engineering & computing》1991,29(1):34-39
Silicone rubber is not, at first sight, a promising material with which to encapsulate a piece of implantable microelectronics
expected to last ten or twenty years. It is well known to be very permeable to water. In fact, if correctly applied, it performs
very well for ten years, possibly longer. The paper considers the part player by osmosis in achieving satisfactory performance
combined with simple technology. 相似文献