Morphological studies of pseudowollastonite for biomedical application

Pseudowollastonite ceramic (psW) composed of CaO·SiO₂ was found to be bioactive in a simulated body fluid environment. The chemical reaction initiated at the material surface resulted in hydroxyapatite (HA)formation. These bone-bonding properties are essential for securing the necessary physico-chemical integration of the material with living bone. Materials behaving in this way can be considered for potential biomedical application as bone tissue substitute for a natural bone repair or replacement as implant. A mechanism of hydroxyapatite formation on pseudowollastonite ceramics surface was investigated during exposure to a simulated body fluid (SBF) for a period of 3 weeks. Morphology and structure of the surface product and its original substrate was examined by thin-film X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. HA crystals were found to form on an amorphous silica intermediate layer. (100) lattice planes of HA were resolved and identified. Concentration of ions in the SBF and pH of the SBF were monitored throughout the exposure. Additional pH measurements were made at the interface of psW with SBF. The HA formation occurred when there was a sudden increase of pH from 7·25 to 10·5 at the interface of psW with SBF as a result of ionic exchange between 2H⁺ and Ca²⁺ within the psW network. This ionic exchange transformed the psW crystals into an amorphous silica phase. The appropriate pH and the ion concentrations were essential for partial dissolution of the amorphous silica phase and subsequent precipitation of a Ca-P rich phase which then transformed to HA.     

Impact and biocompatibility studies on Mg2+-substituted Apatite-derived 3D porous scaffolds for hard tissue engineering

The objective of this study was to develop Mg²⁺-substituted Apatite scaffolds by slip-casting method. The Apatite scaffolds were prepared as engineering constructs with interconnected pore structure with a pore size of 128-194 μm range. The physicochemical properties such as crystalline phase, functional group, microstructure, pore size distribution, and elemental compositions of the scaffolds were characterized. The bioactivity of the developed porous scaffolds was investigated in Simulated Body Fluid (SBF) for various time periods (3 and 7 days). In vitro bioactivity results confirm the hydroxyl Apatite layer formation of the scaffolds and results suggest that the developed microporous scaffold could be used as suitable candidates in bone tissue engineering.     

Rethinking the impact of RG-I mainly from fruits and vegetables on dietary health

Abstract

Rhamnogalacturonan I (RG-I) pectin is composed of backbone of repeating disaccharide units →2)-α-L-Rhap-(1→4)-α-D-GalpA-(1→ and neutral sugar side-chains mainly consisting of arabinose and galactose having variable types of linkages. However, since traditional pectin extraction methods damages the RG-I structure, the characteristics and health effects of RG-I remains unclear. Recently, many studies have focused on RG-I, which is often more active than the homogalacturonan (HG) portion of pectic polysaccharides. In food products, RG-I is common to fruits and vegetables and possesses many health benefits. This timely and comprehensive review describes the many different facets of RG-I, including its dietary sources, history, metabolism and potential functionalities, all of which have been compiled to establish a platform for taking full advantage of the functional value of RG-I pectin.     

Japanese plums (Prunus salicina Lindl.) and phytochemicals – breeding,horticultural practice,postharvest storage,processing and bioactivity

Previous reviews of plum phytochemical content and health benefits have concentrated on the European plum, Prunus domestica L. However, the potential bioactivity of red‐ and dark red‐fleshed Japanese plums, Prunus salicina Lindl., so‐called blood plums, appears to warrant a significant increase in exposure, as indicated in a recent review of the whole Prunus genus. Furthermore, Japanese plums are the predominant plum produced on an international basis. In this review the nutrient and phytochemical content, breeding, horticultural practice, postharvest treatment and processing as well as bioactivity (emphasising in vivo studies) of Japanese plum are considered, with a focus on the anthocyanin content that distinguishes the blood plums. © 2014 State of Queensland Journal of the Science of Food and Agriculture © 2014 Society of Chemical Industry     

Calcium silicate and calcium aluminate cements for dentistry reviewed

Calcium silicate cements were identified as excellent materials for dentistry, particularly for dental procedures contacting the dental pulp or root system. Both calcium silicate and calcium aluminate cements cause the biomineralization (precipitation of hydroxyapatite [HA] phenomena and shield dental tissues from the underlying cement (a foreign body material). The cements also elute ions to stimulate cytokines that contribute to the healing of the dental pulp or in the tissue surrounding the root of a tooth. The cements serve as a foundation for other dental restorative materials. This paper reviews the cement phases, properties, in vivo reactions, and clinical benefits from the use of calcium silicate and calcium aluminate ceramic cements.     

分子构象与药物分子设计

分子构象与分子生物活性有着密切的关系,通过研究分子的构效关系,可以有效避免或缓解繁复的实验研究过程,分子构象识别与分析已成为分子设计的重要研究内容。本文对分子构象在药物分子设计中的作用做了介绍,针对计算机辅助药物设计中受体与配体分子构象的识别过程,进行了分类和阐述,最后就其中存在的问题进行了展望。     

N-磺酰基取代四氢吡咯类化合物的生物活性及合成研究进展

N-磺酰基四氢吡咯类化合物具有多种生物活性,是具有良好应用潜力的一类化合物。本文针对该类化合物的生物活性及其合成方法进行综述。     

Antioxidant and Immunoregulatory Activity of Polysaccharides from Quinoa (Chenopodium quinoa Willd.)

The water-extractable (QWP) and the alkali-extractable (QAP) polysaccharides from quinoa (named QWP and QAP, respectively) and their four polysaccharide sub-fractions (QWP-1, QWP-2, QAP-1 and QAP-2), were isolated and purified by anion-exchange and gel filtration chromatography. QWP-1 and QWP-2 were composed of Rha, Ara, Gal and GalA. QAP-1 and QAP-2 were composed of Rha, Ara, Man, Gal and GalA. Antioxidant and immunoregulatory activities of the polysaccharides were evaluated. The results showed that QWP-1, QWP-2, QAP-1 and QAP-2 had significant antioxidant and immunoregulatory activities. The results suggest that QWP-1, QWP-2, QAP-1 and QAP-2 could be used as potential antioxidants and immunomodulators.     

苯并呋喃[3,2-d]嘧啶类衍生物生物活性及研究进展

阐述了苯并呋喃[3,2-d]嘧啶类化合物在抗菌、抗炎、抗癌、降血糖及抑制血小板聚集和促进长时记忆等方面的应用,对苯并呋喃[3,2-d]嘧啶类衍生物的合成方法进行总结,并且对这类化合物的发展趋势进行了分析。     

功能性海藻酸纤维

海藻酸纤维是以从褐藻中提取出的海藻酸钠为原料制备的一种功能性纤维。近年来,通过离子交换、高分子材料共混等加工方法开发出了一系列具有特性能的海藻酸纤维。介绍了各类功能性海藻酸纤维的生产方法及产品性能。