Fabrication and characterization of a biomimetic composite scaffold for bone defect repair.

For successful bone tissue engineering, scaffolds with tailored properties are a basic requirement. The combination of different available materials not only appears to be desirable but also very challenging. In this study, a composite material consisting of hydroxyapatite and collagen was produced by a biomimetic precipitation method and characterized by X-ray diffraction (XRD) and thermogravimetry (TGA). Subsequently, a suspension-quick-freezing and lyophilization method was used to incorporate the hydroxyapatite into a polymeric matrix consisting of collagen and chitosan. Before physicochemical characterization, the highly porous scaffolds were consolidated by a dehydrothermal treatment (DHT). The main attention was focused on the particle size of hydroxyapatite, which should be in the nanometer range. This is relevant to achieve a homogeneous resorption of the material by osteoclasts. Small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and environmental scanning electron microscopy (ESEM) were used to evaluate the outcome. The results suggest a successful polymeric embedding of nanoscaled hydroxyapatite particles into the matrix of the spongy construct. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

Non-classical light emission from a single electrically driven quantum dot.

Easy to handle light sources with non-classical emission features are strongly demanded in the growing field of quantum communication. We report on single-photon emission from an electrically pumped quantum dot with unmatched spectral purity, making spatial or spectral filtering dispensable.

[Erectile dysfunction of arterial origin as possible primary manifestation of atherosclerosis]. / Disfunzione erettile su base arteriosa come possibile manifestazione primaria dell'aterosclerosi.

The incidence of risk factors atherosclerosis and of vasculogenic importance in a group of patients with erectile failure is presented. As a single risk factor only arterial hypertension is associated significantly with arteriogenic importance. Myocardial ischemia and peripheric arteriopathy are also often associated with arteriogenic impotence. In a high percentage vasculogenic impotence can be the first sign of a generalized arteriopathy. The diagnosis of arteriogenic impotence can therefore have implications which are not only related to erectile failure.