Synthesis of Biomorphic ZrO2-CeO2 Nanostructures by Silkworm Silk Template

以桑蚕丝为模板制备多级生物形态结构ZrO₂-CeO₂. 整个合成过程是由桑蚕丝模板的导向作用决定的. 分析结果表明ZrO₂-CeO₂结晶良好,呈多级网络中空纤维结构,直径为16～28μm,800 oC煅烧后ZrO₂-CeO₂晶粒尺寸约为14 nm.     

产业转移下的海上丝绸之路沿线集装箱港口的投资决策研究

在产业转移背景下,考虑港口服务货运需求与刺激货运需求的双重功效,研究海上丝绸之路沿线产业承接地的港口投资建设问题。首先,在现实交通运输网络中加入虚拟链接构建超级网络,用以刻画制造业的转移、生产和运输过程。其次,建立制造业承接地港口投资决策优化模型,用运输阻抗、地价和工资三个内生变量描述港口投资、产业转移与区域经济之间均衡关系。模型以产业承接地港口收益最大为目标,确定承接地港口的投资规模及费率水平。最后,以斯里兰卡的科伦坡口为例进行数值分析,计算海上丝绸之路沿线港口需求与供给间正向反馈的数量关系及上确界,为优化沿线港口投资实现投资利益最大化提供依据。     

Rapid analysis and characterization of multiple constituents of corn silk aqueous extract using ultra‐high‐performance liquid chromatography combined with quadrupole time‐of‐flight mass spectrometry

Corn silk is a well‐known traditional Chinese medicine that has been widely used for its antidiabetic, antioxidant, antihyperlipidemic, and other effects in China for thousands of years. Numerous studies have revealed that corn silk contains multiple bioactive constituents that are beneficial for human health. However, the constituents of corn silk in vivo remain ambiguous. In this study, high‐throughput ultra‐high‐performance liquid chromatography combined with quadrupole time‐of‐flight mass spectrometry technology using multivariate statistical analysis was established to systematically investigate the constituents migrating into blood from corn silk aqueous extract. As a result, 76 compounds were identified, including caffeic acid and ten of its derivatives, (E)‐p‐coumaric acid and two of its derivatives, ferulic acid and four of its derivatives, and five flavones. Among the identified constituents, 21 constituents, including nine prototype components and 12 metabolites derived from eight components, were characterized in sequence. Based on the significance of the results, the applied approach was powerful for the accurate determination and rapid screening of bioactive components from corn silk aqueous extract. The obtained results are valuable for the in‐depth understanding and further pharmacological study of corn silk aqueous extract.     

Easy conversion of nitrogen‐rich silk cocoon biomass to magnetic nitrogen‐doped carbon nanomaterial for supporting of Palladium and its application

In this study, magnetic nitrogen‐doped carbon (MNC) was fabricated through facile carbonization and activation of natural silk cocoons containing nitrogen and then combined with Fe₃O₄ nanoparticles to create a good support material for palladium. Palladium immobilization on the support resulted in the formation of magnetic nitrogen‐doped carbon‐Pd (MNC‐Pd). The prepared heterogeneous catalyst was well characterized using FT‐IR, TGA, EDX, FE‐SEM, XRD, VSM, and ICP‐OES techniques. Thereafter, the synthesis of biaryl compounds was conducted to investigate the catalyst performance via the reaction of aryl halides and phenylboronic acid. Further, the catalyst could be used and recycled for six consecutive runs without any significant loss in its activity.     

柞蚕丝素／纳米TiO2复合膜的制备及其结构表征

为了获得良好性能的柞蚕丝素复合膜,本文采用复合法制备了不同配比柞蚕丝素/纳米TiO2复合膜,并与纯的丝素膜作了比较,用SEM、DSC、TG和IR进行了表征.SEM测试表明在分散剂聚乙烯醇作用下,适量的纳米TiO2能均匀分散丝素溶液中.DSC测试表明复合膜b、c和d的Tm均高于纯的柞蚕丝素膜a的Tm,然而随着纳米TiO2加入量的继续增加,对应复合膜的Tm有所降低.TG结果表明,随着纳米TiO2加入量的增加,复合膜的热稳定性得到提高.IR测试表明丝素复合膜的结晶结构从Silk I向SilkII转化.     

Advanced Silk Fibroin Biomaterials-Based Microneedles for Healthcare

Microneedles are a promising transdermal drug delivery system that has the advantages of minimal invasiveness, painlessness, and on-demand drug delivery compared with commonly used medical techniques. Natural resources are developed as next-generation materials for microneedles with varying degrees of success. Among them, silk fibroin is a natural polymer obtained from silkworms with good biocompatibility, high hardness, and controllable biodegradability. These properties provide many opportunities for integrating silk fibroin with implantable microneedle systems. In this review, the research progress of silk fibroin microneedles in recent years is summarized, including their materials, processing technology, detection, drug release methods, and applications. Besides, the research and development of silk fibroin in a multidimensional way are analyzed. Finally, it is expected that silk fibroin microneedles will have excellent development prospects in various fields.     

Generation of Haploid Spermatids on Silk Fibroin-Alginate-Laminin-Based Porous 3D Scaffolds

In vitro production of sperm is a desirable idea for fertility preservation in azoospermic men and prepubertal boys suffering from cancer. In this study, a biocompatible porous scaffold based on a triad mixture of silk fibroin (SF), alginate (Alg), and laminin (LM) is developed to facilitate the differentiation of mouse spermatogonia stem cells (SSCs). Following SF extraction, the content is analyzed by SDS-PAGE and stable porous 3D scaffolds are successfully prepared by merely Alg, SF, and a combination of Alg-SF, or Alg-SF-LM through freeze-drying. Then, the biomimetic scaffolds are characterized regarding the structural and biological properties, water absorption capacity, biocompatibility, biodegradability, and mechanical behavior. Neonatal mice testicular cells are seeded on three-dimensional scaffolds and their differentiation efficiency is evaluated using real-time PCR, flow cytometry, immunohistochemistry. Blend matrices showed uniform porous microstructures with interconnected networks, which maintained long-term stability and mechanical properties better than homogenous structures. Molecular analysis of the cells after 21 days of culture showed that the expression of differentiation-related proteins in cells that are developed in composite scaffolds is significantly higher than in other groups. The application of a composite system can lead to the differentiation of SSCs, paving the way for a novel infertility treatment landscape in the future.     

A Silk Fibroin and Peptide Amphiphile‐Based Co‐Culture Model for Osteochondral Tissue Engineering

New biomaterials with the properties of both bone and cartilage extracellular matrices (ECM) should be designed and used with co‐culture systems to address clinically applicable osteochondral constructs. Herein, a co‐culture model is described based on a trilayered silk fibroin‐peptide amphiphile (PA) scaffold cultured with human articular chondrocytes (hACs) and human bone marrow mesenchymal stem cells (hBMSCs) in an osteochondral cocktail medium for the cartilage and bone sides, respectively. The presence of hACs in the co‐cultures significantly increases the osteogenic differentiation potential of hBMSCs based on ALP activity, RT‐PCR for osteogenic markers, calcium analyses, and histological stainings, whereas hACs produces a significant amount of glycosaminoglycans (GAGs) for the cartilage region, even in the absence of growth factor TGF‐β family in the co‐culture medium. This trilayered scaffold with trophic effects offers a promising strategy for the study of osteochondral defects.

     

Hydrogen bonds in silk fibroin-poly(acrylonitrile-co-methyl acrylate) blends: FT–IR study

FT–IR spectroscopy was used to study the specific interactions in polyacrylonitrile-silk fibroin (PAN–SF) and poly(acrylonitrile-co-methyl acrylate)-silk fibroin (PANMA–SF) blends. No specific interaction was found in PAN–SF blends. In PANMA–SF blends, however, a new 1703 cm⁻¹ band, assigned to be hydrogen-bonded carbonyl groups of PANMA, appears, and its intensity depends on the compositions of the blends and the MA contents in PANMA. Furthermore, when the sample was heated, considerable changes in position and intensities of the hydrogen-bonded bands, in both stretching regions of the carbonyl group of PANMA and the hydroxl group of SF, were found, and these changes were irreversible on cooling. Finally, we suggested that the bands of hydrogen bonds in PANMA–SF blends may be the average result of several kinds of possible hydrogen bondings. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 1405–1414, 1997     

低温诱导桑蚕体内腺体相行为的高分辨^13C固体核磁共振研究

为什么蚕在常温常压水溶液条件下即能纺出力学性能优异的蚕丝纤维, 一直是科学家们感兴趣的问题. 在过去的几十年, 人们曾用多种表征手段, 如双折射、扫描电镜、原子力显微镜和电子散射等, 在界观尺度下对蚕在吐丝过程中腺体的相行为进行研究. 发现腺体在靠近吐丝口时呈液晶态, 并认为这是导致蚕丝力学性能的重要因素. 本文则在分子水平尺度下利用核磁共振方法, 对五龄蚕活体在常温和6 ℃下存储数天后解剖的腺体进行研究. 经对化学位移及其线型的各向异性分析发现, 当将体内腺体沿吐丝方向分为3部, 即后部、中部及靠近吐丝口的前部时, 常温下, 腺体后部和中后部分子呈无规线团, 而腺体中中部、中前部和前部分子呈液晶态. 6 ℃时, 中后部分子亦呈液晶态, 前部分子排列则各向异性更大, 说明更为有序. 这种液晶态呈分形结构, 在小于纳米尺度下为无规线团, 大于纳米尺度呈有序排列. 这表明, 降温过程可使呈无规线团的丝素蛋白分子转变为液晶态, 其效果如同蚕在吐丝过程中对其腺体施加的剪切应力. 该结果对于人们探索人工合成高性能类丝素纤维的纺丝工艺和条件将有启发和指导作用.