Synthesis of ZnO nanoparticles by flame spray pyrolysis and characterisation protocol

There is uncertainty concerning the potential toxicity of zinc oxide (ZnO) nanoparticles, which may be attributed in part to a lack of understanding with regard to the physiochemical properties of the nanoparticles used in toxicological investigations. This paper reports the synthesis of a ZnO nanopowder by flame spray pyrolysis and demonstrates that the typically employed characterisation techniques such as specific surface area measurement and X-ray diffraction provide insufficient information on the sample, especially if it is intended for use in toxicity studies. Instead, a more elaborate characterisation protocol is proposed that includes particle morphology as well as detailed compositional analysis of the nanoparticle surface. Detailed transmission electron microscopy analysis illustrated the polydispersity within the sample: particles were elongated in the c-crystallographic direction, with average Ferret length ∼23 nm and Ferret width ∼14 nm. Dynamic light scattering (0.1 w/v% in deionised water, pH 7.4) revealed the particles were agglomerated with a modal secondary particle size of ∼1.5 μm. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated the presence of carbonate and hydroxide impurities on the surface of the ZnO nanoparticles and an increase of such impurities was observed as the sample was aged, which might influence the nanoparticle dissolution and/or cellular uptake behaviour. These data will be utilised, in order to facilitate the interpretation and understanding of results from toxicological investigations using in vitro cell lines

The Advancement of Biomaterials in Regulating Stem Cell Fate.

Stem cells are well-known to have prominent roles in tissue engineering applications. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can differentiate into every cell type in the body while adult stem cells such as mesenchymal stem cells (MSCs) can be isolated from various sources. Nevertheless, an utmost limitation in harnessing stem cells for tissue engineering is the supply of cells. The advances in biomaterial technology allows the establishment of ex vivo expansion systems to overcome this bottleneck. The progress of various scaffold fabrication could direct stem cell fate decisions including cell proliferation and differentiation into specific lineages in vitro. Stem cell biology and biomaterial technology promote synergistic effect on stem cell-based regenerative therapies. Therefore, understanding the interaction of stem cell and biomaterials would allow the designation of new biomaterials for future clinical therapeutic applications for tissue regeneration. This review focuses mainly on the advances of natural and synthetic biomaterials in regulating stem cell fate decisions. We have also briefly discussed how biological and biophysical properties of biomaterials including wettability, chemical functionality, biodegradability and stiffness play their roles

The Formation of Building Industry Samples through the Analysis of Individual Projects:  Two Australian Examples

Australasian University Building Educators Association Conference (AUBEA

The SARS coronavirus E protein interacts with PALS1 and alters tight junction formation and epithelial morphogenesis

Intercellular tight junctions define epithelial apicobasal polarity and form a physical fence which protects underlying tissues from pathogen invasions. PALS1, a tight junction-associated protein, is a member of the CRUMBS3-PALS1-PATJ polarity complex, which is crucial for the establishment and maintenance of epithelial polarity in mammals. Here we report that the carboxy-terminal domain of the SARS-CoV E small envelope protein (E) binds to human PALS1. Using coimmunoprecipitation and pull-down assays, we show that E interacts with PALS1 in mammalian cells and further demonstrate that the last four carboxy-terminal amino acids of E form a novel PDZ-binding motif that binds to PALS1 PDZ domain. PALS1 redistributes to the ERGIC/Golgi region, where E accumulates, in SARS-CoV-infected Vero E6 cells. Ectopic expression of E in MDCKII epithelial cells significantly alters cyst morphogenesis and, furthermore, delays formation of tight junctions, affects polarity, and modifies the subcellular distribution of PALS1, in a PDZ-binding motif-dependent manner. We speculate that hijacking of PALS1 by SARS-CoV E plays a determinant role in the disruption of the lung epithelium in SARS patients. © 2010 K.-T. Teoh et al.link_to_subscribed_fulltex

Oxidative damage in ischemic stroke revealed using multiple biomarkers

Background and Purpose-We investigated changes in oxidative damage after ischemic stroke using multiple biomarkers. Methods-Serial blood and urine samples of ischemic stroke subjects and age-matched control subjects were assayed for F2-isoprostanes, hydroxyeicosatetraenoic acid products, F4-neuroprostanes, 24-hydroxycholesterol, allantoin, and urate. Results-Sixty-six stroke subjects (mean age, 65 years; median National Institutes of Health Stroke Scale 17) and 132 control subjects were recruited. A bimodal pattern of change was observed in plasma and urinary F2-isoprostanes and plasma 24-hydroxycholesterol. The rise in plasma hydroxyeicosatetraenoic acid products, F4-neuroprostanes, and allantoin was highest 6 to 12 hours after stroke onset, whereas plasma urate was significantly lower than controls on Days 1 to 3. After adjusting for age and baseline National Institutes of Health Stroke Scale, baseline plasma esterified hydroxyeicosatetraenoic acid products (OR, 1.01; 95% CI, 1.01 to 1.02), plasma urate (1.01; 1.00 to 1.01), and plasma free F4-neuroprostanes (2.73; 1.76 to 3.93) were associated with 90-day good functional recovery (modified Rankin Scale ≤1). Conclusions-Multiple markers of oxidative damage are increased immediately after stroke and remain elevated for several days. Recognition of these temporal changes may help design better antioxidant treatment trials for acute ischemic stroke. © 2011 American Heart Association, Inc.link_to_subscribed_fulltex