Preparation and Characterization of Nano-Se/Silk Fibroin Colloids

A solution-phase approach to the synthesis of nano-Se/silk fibroin colloids(NSeSFC) by reducing selenious acid solution with silk fibroin(SF) was proposed, and the composites were in situ prepared by macrowave method. The nanocomposites were characterized with ultraviolet-visible(UV-Vis) absorption spectrometry, resonance Rayleigh scattering(RRS) spectrometry and transmission electron microscopy(TEM). The nano-Se(0) solution exhibited the strongest resonance Rayleigh scattering at 579 nm. Through the RRS di...     

Thermostimulated creep in amorphous polyolefins. I

The thermostimulated creep of two amorphous polyolefins having the repeating unit ─(CH₂)_mC(CH₃)2─, where m = 2 and 3, was investigated from 77° to 350°. Two relaxation processes are distinguished: a secondary relaxation is observed at 138 and 113°, respectively, for m = 2 and m = 3; a primary relaxation is found around the glass transition. These relaxations have been resolved in their elementary components. From the data acquired, the mechanical losses have been calculated and compared with data from an inverted torsional pendulum. The activation energy found for the secondary relaxation—0.26 eV at 138° K for the amorphous polyolefin with m = 2 and 0.19 eV at 113° K for the polyolefin with m = 3—confirms that this relaxation mode is associated with restricted backbone motion.     

In vitro and in vivo degradation behavior of aqueous-derived electrospun silk fibroin scaffolds

We investigated the in vitro degradation behavior of the electrospun silk fibroin (SF) scaffolds by protease XIV. Phosphate-buffered saline (PBS) without enzyme was used as a control. About 65% of the electrospun SF scaffolds were degraded within 24 d in protease XIV, while almost no scaffolds were degraded in PBS. A great deal of fragments was visible in protease XIV solution. SEM indicated surface erosion of the scaffolds increased during protease degradation with increasing exposure time. FTIR and XRD indicated the crystalline structure of the scaffolds decreased after protease degradation for 24 d, and a degradation mechanism was proposed. Furthermore, the results of the in vivo degradation by implantation in rats showed that the scaffolds were completely degraded in vivo after implantation for 8 weeks and well tolerated by the host animals. The insights gained in this study can serve as a guide to match desired degradation behavior with specific applications for the electrospun SF scaffolds, such as tissue engineering and drug delivery.     

STUDY ON THE CATALYTIC ABILITY OF BIOACTIVE FIBERS

Two kinds of water-soluble metallophthalocyanines (Mt2Pc2), binuclear cobalt phthalocyanine (Co2Pc2) and binuclear ferric phthalocyanine (Fe2Pc2), were supported on silk fibers and modified viscose fibers to construct bioactive fibers of mimic enzyme, Mt2Pc2 used as the active center of bioactive fibers, viscose and silk fibers as the microenvironments. The catalytic oxidation ability of bioactive fibers on the malodors of methanthiol and hydrogen sulfide was investigated at room temperature. The experimental results demonstrated that the catalytic activity of such bioactive fibers was tightly correlative to the types of bioactive fibers and substrates.     

Mineralization of HA crystals regulated by terephthaloyl chloride-modified silk fibroin films

Terephthaloyl chloride(DB)-modified silk fibroin(SF) films were immersed into 1.5 times simulated body fluid(1.5 SBF) to regulate the mineralization of hydroxyapatite(HA) crystals at about 36.5℃for 24 h.UV was used to prove that the new bonds form between the DB and SF.The structure and morphology of the SF/HA were investigated by FTIR,ICP,XRD and SEM.The results showed that the apatite deposited on the matrix of SF mainly was HA.HA was self-assembled on the matrix of SF and formed three-dimensional framework when the weight ratio of DB/SF was 0.30.The content of DB affected the structure and morphology of the apatite composites deposited on the SF films.     

Study on Light Aging of Silk Fabric by Fourier Transform Infrared Spectroscopy and Principal Component Analysis

To investigate environmental effect on cultural materials, Fourier transform infrared technique (FTIR/ATR) was applied to analyze the silk aging process. Changes in chemical and conformational structures of silk fabric undergoing ultraviolet induced degradation were investigated. The IR spectra provided strong bands of photosensitive amide I, II, and III. For overlapping amide III region, both of the original and second-derivative IR spectra revealed that UV irradiation induced the structural transformation from β-sheet domain to β-turn conformation, which was supported by the increase of β-turn marker band at 1015 cm^?1 associated with polyglycine. Additionally the reduced bands associated with (GlyAla)_n segment at 1000 and 976 cm^?1, and the decreased band at 1070 cm^?1 related to β-sheet structure also illustrated the conformational transition. Furthermore, we applied a chemometric method of principal component analysis for the evaluation of silk degradation based on variations in amide I spectral region. The score plot using the first two principal components effectively summarized the general trend of silk-aging and revealed the quick degradation appeared in the initial stages (12 h and 24 h) and the 108-hr stage. This work provides a potential novel application of the infrared spectroscopy in noninvasive qualitative and quantitative investigation of silk degradation.     

蚕丝丝胶－锰（Ⅱ）络合物的制备及其氧化催化活性的研究

以蚕丝丝胶作为高分子配位体制备丝胶－锰（Ⅱ）络合物，用吸氧法考察了丝胶－锰（Ⅱ）络合物对ＤＬ和Ｌ－３，４－二羟基苯基丙氨酸（ＤＯＰＡ）的氧化催化活性，通过ｐＨ滴定曲线、红外光谱证明丝胶－锰（Ⅱ）络合物确实生成，在不同的ｐＨ下Ｍｎ与氨基配位数不同，并且有不对称选择催化氧化活性。     

蚕腺体内和再生丝素蛋白水溶液的性能研究

用偏光显微镜观察了蚕腺体内和再生丝素蛋白水溶液的流动状态和各向异性现象,用乌氏粘度计测试了其流出时间,并用HAKKE流变仪测试了其粘度。结果发现蚕腺体内和再生丝素蛋白水溶液的性质差别非常大,认为丝素蛋白水溶液在蚕腺体内存在一个逐步熟成的过程。随着丝素蛋白水溶液在腺体内的前移,丝素蛋白分子逐渐沿移动方向取向而呈有序态,最终成为粘度非常大的各向异性的凝胶体,而再生丝素蛋白水溶液是粘度非常低的各向同性溶液。这些差异表明,丝素蛋白水溶液在蚕腺体内的熟成过程是蚕能够吐出优良蚕丝的关键步骤,要想制备出高性能的纤维,在“仿生纺丝”之前,首先要“仿生制备纺丝液”。     

离子液体中丝素/聚乙烯醇共混膜的制备及表征

采用离子液体氯化1-丁基-3-甲基咪唑（BMIMCl）溶解丝素（SF）,获得BMIMCl/SF溶液,再与聚乙烯醇（PVA）水溶液共混,制备得到PVA/SF共混膜。共混膜经红外光谱、紫外可见光谱、对水接触角、拉力试验等表征。结果表明,溶液共混使共混膜中SF与PVA发生了化学键键合,乙醇处理使共混膜中SF主要以β-折叠结构存在。随着SF含量的增加,共混膜的透光率逐渐变小,亲水性则逐渐增大。     

中国的新综合性视野和远瞻性愿景：“一带一路”倡议与亚投行

中国在将近两个世纪之中一直都被困于许多发展中国家的基本窘境：现代西方既是其帝国主义敌人也是其发展模范。在其近现代历史中,一再从完全拒绝西方转到完全模仿西方的极端。如今,近乎两个世纪之后,中国终于逐步走向了一个新的综合性视野和远瞻性愿景,既采纳源自其反帝革命过程中的优良传统,也采纳其西式现代化经验中的优点来想象、推进中国的未来。这个改变很好地体现在中国最近的“一带一路”倡议和所组建的亚洲基础设施投资银行。但西方学术仍然多局限于其源自冷战时期中的善恶分明和对立的视野,一再将不择手段地谋求和使用权力的动机投射于中国。即便是中国自身的学术,由于西方政治学传统中完全聚焦于权力及其运作的论析的影响,大多要么忽视了中国不同的,既是道德化的、也是实用性的思维方式,要么仅是官方话语的转述或阐释,不多考虑其实际运作和远瞻性愿景。我们需要更清楚地了解中国的新设想来更好地认识其最新的经济发展进路和其对世界未来的新综合性视野和深层的远瞻性愿景。对比新设想和最近十几年的农村发展战略,我们可以更清楚和完全地看到两者间的巨大不同。