Extractives in the cones of Pinus species

Amount and composition of lipophilic and hydrophilic extractives were analyzed in the cones of five coniferous species, namely Pinus halepensis, P.?brutia, P.?pinea, P. sylvestris and P.?nigra, growing natively in Turkey. Lipophilic extractives amounts, identified by GC, were found to be the highest in P.?brutia (35.1?mg?g^?1) and P.?halepensis (31.3?mg?g^?1) while the lowest values were found in P.?sylvestris (9.0?mg?g^?1). Resin acids were the major lipophilic group in all cones. The predominant resin acids were abietic acid in P.?pinea, P.?halepensis and P.?brutia, dehydroabietic acid in P.?sylvestris, and isopimaric acid in P.?nigra. Compared to lipophilic extractives, the amount of total hydrophilic extractives showed similar gravimetric values while sugars and sugar alcohols were the dominant group.     

基于教材文本的本体学习方法研究

教材文本相对于普通文本有其独特性。通过分析教材目录的特征,获取领域词汇的种子概念。通过分析教材正文中知识点的特征,提取出知识点的特征值,然后利用决策树C4.5算法对知识点类型进行识别,实现了教材文本的本体学习。     

PEG and PEG-peptide based doxorubicin delivery systems containing hydrazone bond

mPEG and mPEG-peptide based drug delivery systems were prepared by conjugating doxorubicin (DOX) to these carrier molecules via hydrazone bond. The peptide, AT1, with a sequence of CG₃H₆G₃E served as mPEG and doxorubicin attachment site. Histidines were incorporated to the sequence to improve pH responsiveness of the carrier molecule. Hydrodynamic diameters (mean sizes) of mPEG-based drug delivery system (mPEG-HYD-DOX) were measured as 9?±?0.5 and 7?±?0.5 nm at pH 7.4 and pH 5.0, respectively. Mean size of the aggregates of the peptide containing drug delivery system, mPEG-AT1-DOX, was determined as 12?±?2 nm at neutral pH. At pH 5.0, on the other hand, mPEG-AT1-DOX exhibited a size distribution between 20 and 100 nm centered at about 40 nm. Comparison of % DOX release values of the drug delivery systems obtained at pH 7.4 and pH 5.0 indicated that mPEG-AT1-DOX has enhanced pH sensitivity. DOX equivalent absolute IC₅₀ values were obtained as 0.96?±?0.51, 21.9?±?5.9, and 5.55?±?0.75 μg/mL for free DOX, mPEG-HYD-DOX, and mPEG-AT1-DOX, respectively. Considering more pronounced pH sensitivity and cytotoxicity of mPEG-AT1-DOX, the use of both pH responsive functional groups and acid cleavable chemical bond between the carrier molecule and drug can be a promising approach in the design of drug delivery systems for cancer therapy.     

Fabrication of stretchable and high-filtration performance melt-blown nonwoven webs for PM0.3 aerosol filtration

Polypropylene (PP) is a semi-crystalline polymer that displays simple manufacturing, high stiffness, lightweight, chemical resistance, and inexpensive. However, PP has significant drawbacks, such as poor brittleness at low temperatures, high shrinkage ratio, and low impact resistance, which limit its development. Thermoplastic polyurethane (TPU) possesses recyclable and eco-friendly characteristics, along with the elasticity of rubber and exceptional mechanical properties. In this study, a flexible and high-filtration performance PP-TPU textile material was developed by melt-blowing for filtering PM_0.3 aerosols. For the first time, a melt-blown PP-TPU nonwoven was used as an air filter. The fiber morphological studies exhibited that addition of 10 and 20 wt.% TPU into PP resulted in a fiber diameter increment from 0.94 to 1.24 μm. Also, melt-blown PP-TPU forms helical fibers, which are different from fibers noticed in melt-blown PP. Corona-charged double-layer 80PP-20TPU nonwovens have a filtration efficiency of 99.25% and quality factor (QF) of 0.13 mm H₂O⁻¹ at an air flow rate of 95 L/min. Moreover, PP's tensile strength was increased by 72.22%, and elongation was raised by 38.1% with the addition of 20 wt.% TPU. Thus, PP-TPU melt-blown composites may bring novel perspectives into the design and development of high-performance filtering materials for a variety of applications.     

Wood and bark volatile compounds of Laurus nobilis L.

Wood and bark parts of Laurus nobilis L. were extracted with two different methods to determine the volatile compounds. They were analyzed with GC/MS. Monoterpenes were determined as the principal group of the bark volatiles whereas sesquiterpenes are the main components in wood extractives. The main compounds in bark are 1.8-cineol and eugenol, while dehydrocostunolide in the wood extract.