Synthesis of Indium Nanowires by Galvanic Displacement and Their Optical Properties

<p>Abstract</p> <p>Single crystalline indium nanowires were prepared on Zn substrate which had been treated in concentrated sulphuric acid by galvanic displacement in the 0.002 mol L^&#8722;1In₂(SO₄)₃-0.002 mol L^&#8722;1SeO₂-0.02 mol L^&#8722;1SDS-0.01 mol L^&#8722;1citric acid aqueous solution. The typical diameter of indium nanowires is 30 nm and most of the nanowires are over 30 &#956;m in length. XRD, HRTEM, SAED and structural simulation clearly demonstrate that indium nanowires are single-crystalline with the tetragonal structure, the growth direction of the nanowires is along [100] facet. The UV-Vis absorption spectra showed that indium nanowires display typical transverse resonance of SPR properties. The surfactant (SDS) and the pretreatment of Zn substrate play an important role in the growth process. The mechanism of indium nanowires growth is the synergic effect of treated Zn substrate (hard template) and SDS (soft template).</p

Sfrp Controls Apicobasal Polarity and Oriented Cell Division in Developing Gut Epithelium

Epithelial tubular morphogenesis leading to alteration of organ shape has important physiological consequences. However, little is known regarding the mechanisms that govern epithelial tube morphogenesis. Here, we show that inactivation of Sfrp1 and Sfrp2 leads to reduction in fore-stomach length in mouse embryos, which is enhanced in the presence of the Sfrp5 mutation. In the mono-cell layer of fore-stomach epithelium, cell division is normally oriented along the cephalocaudal axis; in contrast, orientation diverges in the Sfrps-deficient fore-stomach. Cell growth and apoptosis are not affected in the Sfrps-deficient fore-stomach epithelium. Similarly, cell division orientation in fore-stomach epithelium diverges as a result of inactivation of either Stbm/Vangl2, an Fz/PCP component, or Wnt5a. These observations indicate that the oriented cell division, which is controlled by the Fz/PCP pathway, is one of essential components in fore-stomach morphogenesis. Additionally, the small intestine epithelium of Sfrps compound mutants fails to maintain proper apicobasal polarity; the defect was also observed in Wnt5a-inactivated small intestine. In relation to these findings, Sfrp1 physically interacts with Wnt5a and inhibits Wnt5a signaling. We propose that Sfrp regulation of Wnt5a signaling controls oriented cell division and apicobasal polarity in the epithelium of developing gut

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference