Matrix change of bone grafting substitute after implantation into guinea pig bulla

Background: Many different surgical techniques have been developed to remove open mastoid cavities. In addition to autologous materials, alloplastic substances have been used. A very slow absorption of these materials and extrusion reactions have been reported. We investigated a newly developed, highly porous bone grafting material to eliminate open mastoid cavities, in an animal model. To characterise the transformation process, the early tissue reactions were studied in relation to the matrix transformation of the bone material. Material and methods: NanoBone (NB), a highly porous bone grafting material based on calcium phosphate and silica, was filled into the open bullae from 20 guinea pigs. The bullae were examined histologically. Energy dispersive X-ray spectroscopy (EDX) was used to investigate the change in the elemental composition at different sampling times. The surface topography of the sections was examined by electron microscopy. Results: After 1 week, periodic acid-Schiffs (PAS) staining demonstrated accumulation of glycogen and proteins, particularly in the border area of the NB particles. After 2 weeks, the particles were evenly coloured after PAS staining. EDX analysis showed a rapid absorption of the silica in the bone grafting material. Conclusions: NanoBone showed a rapid matrix change after implantation in the bullae of guinea pigs. The absorption of the silica matrix and replacement by PAS-positive substances like glycoproteins and mucopolysaccharides seems to play a decisive role in the degradation processes of NB. This is associated with the good osteoinductive properties of the material

Die Bestimmung der γ-Glutamyltranspeptidase im Urin von nierengesunden und nierenkranken Personen mit einer automatischen kinetischen Methode

Peer Reviewe

Isolation of a wide range of minerals from a thermally treated plant: Equisetum arvense, a Mare’s tale

Silica is the second most abundant biomineral being exceeded in nature only by biogenic CaCO3. Many land plants (such as rice, cereals, cucumber, etc.) deposit silica in significant amounts to reinforce their tissues and as a systematic response to pathogen attack. One of the most ancient species of living vascular plants, Equisetum arvense is also able to take up and accumulate silica in all parts of the plant. Numerous methods have been developed for elimination of the organic material and/or metal ions present in plant material to isolate biogenic silica. However, depending on the chemical and/or physical treatment applied to branch or stem from Equisetum arvense; other mineral forms such glass-type materials (i.e. CaSiO3), salts (i.e. KCl) or luminescent materials can also be isolated from the plant material. In the current contribution, we show the chemical and/or thermal routes that lead to the formation of a number of different mineral types in addition to biogenic silica

Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging

Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by using high resolution (<1 μm) Confocal Raman microscopy. Two-dimensional spectral maps were acquired on cross sections of Equisetum hyemale and Raman images calculated by integrating over the intensity of characteristic spectral regions. This enabled direct visualization of differences in chemical composition and extraction of average spectra from defined regions for detailed analyses, including principal component analysis (PCA) and basis analysis (partial least square fit based on model spectra). Accumulation of silica was imaged in the knobs and in a thin layer below the cuticula. In the spectrum extracted from the knob region as main contributions, a broad band below 500 cm−1 attributed to amorphous silica, and a band at 976 cm−1 assigned to silanol groups, were found. From this, we concluded that these protrusions were almost pure amorphous, hydrated silica. No silanol group vibration was detected in the silicified epidermal layer below and association with pectin and hemicelluloses indicated. Pectin and hemicelluloses (glucomannan) were found in high levels in the epidermal layer and in a clearly distinguished outer part of the hypodermal sterome fibers. The inner part of the two-layered cells revealed as almost pure cellulose, oriented parallel along the fiber

Structure of mono- And multilayer Langmuir-Blodgett films from Cd arachidate and Ca arachidate

Langmuir–Blodgett (LB) films of Cd arachidate and Ca arachidate with thicknesses of 1, 3, 9, and 25 layers were investigated using near edge x‐ray absorption fine structure (NEXAFS spectroscopy), small angle x‐ray scattering (SAXS), and reflected high energy electron diffraction (RHEED). The results from the x‐ray diffraction experiments on layer thickness and interface roughness complement the structural information from NEXAFS on the average tilt angle of the alkyl chains in real space. The RHEED measurements confirm these findings and give additional information on the lateral order in these organic films. We find that the monolayer film shows a substantial degree of disorder, while for three and more LB layers, the molecular orientation is virtually identical to that of the corresponding fatty acid salts, i.e., the hydrocarbon chains are oriented perpendicular to the substrate surface in an all‐trans conformation. Furthermore, a simplified and more robust analysis scheme for NEXAFS data obtained for hydrocarbon chains is presented

Magnetic studies on mass-selected iron particles

We have investigated the magnetic properties of mass-selected iron clusters using the Magneto-Optical Kerr effect (MOKE) in longitudinal geometry. For the production of these clusters, a newly developed continuous arc cluster ion source (ACIS) was applied. The source is based on cathodic arc erosion in inert gas environment and subsequent expansion into high vacuum. Its intensity and stability allows mass selection within a wide size range. The source efficiency is demonstrated in deposition experiments and transmission electron microscopy. For mass-selected iron particles deposited into a silver matrix we could observe a change in the magnetic behaviour from ferromagnetism to superparamagnetism around a size of 10 nm at room temperature