ABSTRACT
Basalt fibre is derived from volcanic rocks and has similar mechanical properties as glass fibre. However, poor fibre-matrix compatibility and processing issues are the main factors that have restricted the mechanical performance of basalt fibre-reinforced thermoplastic composites (BFRTP). In this work, basalt continuous fibre composites with polypropylene (PP) and polycarbonate (PC) matrices were studied. The composites were processed by compression moulding, and a processing study was conducted to achieve good quality composites. For the BF-PC composites, the optimisation of material preparation and processing steps allowed the polymer to impregnate the fibres with minimal fibre movements, hence improving impregnation and mechanical properties. For BF-PP composites, a compatibiliser was required to improve fibre-matrix compatibility. The compatibiliser significantly improved the tensile and impact strength values for short BF-PP composites and continued to increase at 40 wt%. Furthermore, the analytical modelling of the Young's moduli indicated that the induced fibre orientation during processing for short BF-PP composites and unidirectional (UD) BF-PC composites had better stress transfer than that of UD BF-PP composites.
ABSTRACT
Vascular graft replacement remains the optimal treatment option for many vascular diseases despite advances in endovascular surgery. In this study, we proposed the use of surface topographical cues to align and maintain the phenotype of vascular smooth muscle cells (vSMCs) which were reported as one of the vital limitations for successful graft replacement. An auxiliary electrospinning setup has been developed to collect circumferentially aligned fibres on a 3D tubular format; this micro-architecture was found to be similar to the tunica media layer of blood vessels. The presence of aligned fibres served as a signaling modality to induce cell alignment and the maintenance of the contractile phenotype. vSMCs cultured on the 3D aligned fibrous substrate were found to exhibit better cell proliferation ability and enhanced cell-shape directionality. The functional expression of the two representative intracellular contractile proteins (i.e. α-SMA and MHC) was found to exhibit definitive markers that are orderly organized as microfilament bundles. Collectively, the result suggests a possibility of adapting the 3D aligned tubular scaffold to enhance and regulate cell function along with the additional tunability of scaffold diameter and thicknesses for tailoring to the needs of individual patients or future ex vivo studies.
ABSTRACT
From the fruit of Pandanus tectorius Parkinson ex Du Roi, one new (1) and six known aldehyde compounds (2-7) were isolated by various chromatography methods. Based on their spectroscopic data, these compounds were identified as (Z)-4-hydroxy-3-(4-hydroxy-3-methylbut-2-en-1-yl) benzaldehyde (1), p-hydroxybenzaldehyde (2), syringaldehyde (3), (E)-ferulaldehyde (4), (E)-sinapinaldehyde (5), vanillin (6) and 5-hydroxymethylfurfual (7). The α-glucosidase inhibitory activity of all compounds was measured. The isolated compounds (1-6) showed better α-glucosidase inhibitory activity (IC50 values ranging from 36.5 to 192.4 µM) than the standard drug acarbose (IC50 = 214.5 µM).
