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The objectives of this research are: (1) to assess selected formulation-relevant physical properties of several commercial
Feverfew extracts, including flowability, hygroscopicity, compressibility and compactibility (2) to develop and validate a
suitable extraction method and HPLC assay, and (3) to determine the parthenolide content of several commercial Feverfew extracts.
Carr’s index, minimum orifice diameter and particle-particle interaction were used to evaluate powder flowability. Hygroscopicity
was evaluated by determining the equilibrium moisture content (EMC) after storage at various % relative humidities. Heckle
analysis and compression pressure-radial tensile strength relationship were used to represent compression and compaction properties
of feverfew extracts. An adapted analytical method was developed based on literature methods and then validated for the determination
of parthenolide in feverfew. The commercial extracts tested exhibited poor to very poor flowability. The comparatively low
mean yield pressure suggested that feverfew extracts deformed mainly plastically. Hygroscopicity and compactibility varied
greatly with source. No commercial feverfew extracts tested contained the label claimed parthenolide. Even different batches
from the same manufacturer showed significantly different parthenolide content. Therefore, extract manufactures should commit
to proper quality control procedures that ensure accurate label claims, and supplement manufacturers should take into account
possible differences in physico-chemical properties when using extracts from multiple suppliers. 相似文献
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Shuyan Shao Jian Liu Jonas Bergqvist Shengwei Shi Clemens Veit Uli Würfel Zhiyuan Xie Fengling Zhang 《Liver Transplantation》2013,3(3):349-355
A solution‐processed neutral hole transport layer is developed by in situ formation of MoO3 in aqueous PEDOT:PSS dispersion (MoO3‐PEDOT:PSS). This MoO3‐PEDOT:PSS composite film takes advantage of both the highly conductive PEDOT:PSS and the ambient conditions stability of MoO3; consequently it possesses a smooth surface and considerably reduced hygroscopicity. The resulting bulk heterojunction polymer solar cells (BHJ PSC) based on poly[2,3‐bis‐(3‐octyloxyphenyl)quinoxaline‐5,8‐diyl‐alt‐thiophene‐2,5‐diyl] (TQ1):[6,6]‐phenyl‐C71‐butyric acid methyl ester (PC70BM) blends using MoO3‐PEDOT:PSS composite film as hole transport layer (HTL) show considerable improvement in power conversion efficiency (PCE), from 5.5% to 6.4%, compared with the reference pristine PEDOT:PSS‐based device. More importantly, the device with MoO3‐PEDOT:PSS HTL shows considerably improved stability, with the PCE remaining at 80% of its original value when stored in ambient air in the dark for 10 days. In comparison, the reference solar cell with PEDOT:PSS layer shows complete failure within 10 days. This MoO3‐PEDOT:PSS implies the potential for low‐cost roll‐to‐roll fabrication of high‐efficiency polymer solar cells with long‐term stability at ambient conditions. 相似文献
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【目的】探索不同培养时间下深色有隔内生真菌(CGMCC17463)合成胞外聚合物(extracellular polymeric substance, EPS)的产量及组成变化。【方法】通过摇瓶培养深色有隔内生真菌(dark septate endophytes, DSE),分析不同培养时间合成的EPS产量及应用的差异。【结果】摇瓶发酵试验表明,第4-12天,DSE生长趋于对数期和稳定期,EPS合成速率较快,在第12天产量达到1.41 g/L,之后EPS的合成速率逐渐降低。EPS组分分析结果表明,在相同质量的EPS中,第12天的胞外多糖含量较高,随着DSE生长进入稳定期至衰亡期,菌丝裂解,EPS中蛋白含量显著提高。官能团分析结果表明,不同培养时间的EPS中官能团种类并未发生变化,仅存在官能团含量上的改变。扫描电子显微镜和粒径分析结果表明,随着培养时间的增加,EPS的结构逐渐发生改变,EPS中分子粒径小于5μm所占比例逐渐提高,分子粒径大于100μm所占比例逐渐降低。另外,EPS的生物活性测定结果表明,不同培养时间合成的EPS均具有清除氧自由基和保水的能力,并且这种能力受EPS组分相对丰... 相似文献
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