Nanoscale patterning of organosilane molecular thin films from the gas phase and its applications: fabrication of multifunctional surfaces and large area molecular templates for site-selective material deposition.

A simple methodology to fabricate micrometer- and nanometer-scale patterned surfaces with multiple chemical functionalities is presented. Patterns with lateral dimensions down to 110 nm were made. The fabrication process involves multistep gas-phase patterning of amine, thiol, alkyl, and fluorinated alkyl-functional organosilane molecules using PDMS molds as shadow masks. Also, a combination process of channel diffused plasma etching of organosilane molecular thin films in combination with masked gas-phase deposition to fabricate multilength scale, multifunctional surfaces is demonstrated.

On-line monitoring of a microwave-assisted chemical reaction by nanolitre NMR-spectroscopy.

We report the use of a nanolitre nuclear magnetic resonance (NMR) spectroscopy microfluidic chip hyphenated to a continuous-flow microlitre-microwave irradiation set-up, for on-line monitoring and rapid optimization of reaction conditions.

Reduction of time-varying nanotesla magnetic fields from electric power lines by twisting.

Time-varying magnetic fields generated by electrical power lines in the laboratory can disturb electron microscope imaging. Modern microscopes require these fields to be below 10 nT [2]. We calculated and measured magnetic fields from straight and twisted current-carrying wires, and show that without twisting, this value cannot be reached.

The influence of X-ray radiation on the mineral/organic matrix interaction of bone tissue: an FT-IR microscopic investigation.

Fourier transform infrared microscopy was used to investigate human cortical bone samples before and after treatment with increasing doses of X-ray radiation. Especially the spectral region of the v1 and v3 phosphate vibrations of hydroxyapatite, the main mineral component of bone, and the region of the amide I and amide II vibrational bands due to the collagen extracellular matrix were examined. Major spectral changes in the phosphate region between 1250-1000 cm(-1) occur after irradiation doses between 1 and 4 Gray. These findings are explained by a decrease in size of mineral crystallites and by variances of the toichiometric/non-stoichiometric apatite composition. The Ca2+ /PO4(3-) /HPO4(2-) composition in the biological apatite is altered near the bone surface. The secondary structure of the collagen matrix is not affected by cumulative irradiation up to doses of 15 Gray as indicated by the unchanged frequency maximum and contour shape of the amide I band between 1600-1700 cm(-1) . However, side chain carboxylate groups of the collagen matrix that are involved in coordination with apatite bound calcium ions are partially removed by decarboxylation upon irradiation. Concomitantly, a loss of acidic phosphate groups due to a formation of phosphate groups with bound calcium is observed. These changes on a molecular level can be correlated with alterations in the mechanical properties of the bone samples, e.g. with an increased embrittlement as deduced from experiments with a scanning acoustic microscope.

[Mechanical changes in bone after roentgen irradiation with low dosage]. / Mechanische Veränderungen des Knochens nach Röntgenbestrahlung mit niedrigen Dosen.

We investigated the micromechanical properties using doses from 1 up to 7 Gray and could observe a roughening on the surface of the bone material in the microscopic range by scanning acoustic microscopic measurements. In addition, a preceding irradiation promoted an extension of microcracks during the polishing process indicating an embrittlement. After irradiation and removal of the surface layer, the SAM measurements indicate a preferential increasing of hardness of softer regions. These results are consistent with our measurements by environmental scanning electron microscopy.

Quantitative measurements of the mechanical properties of human bone tissues by scanning acoustic microscopy.

The quantitative scanning acoustic microscopy is used for determination of the acoustic impedance of human femoral bones in the micrometer scale. The method is introduced and demonstrated at prepared bone surfaces with different cutting angles referring to the bone axis. First measurements show weak variations of the elastomechanical properties with angles.

A comparative study of the application of scanning acoustic microscopy and confocal laser scanning microscopy to the structural assessment of human bones.

The Scanning Acoustic Microscope (SAM) is used to image mechanical structure and to measure the sound velocity in micrometers of in vitro samples from human bone. A similar principle is used in confocal laser scanning microscopy. The same sample is imaged by both methods and the results compared. We concentrated on the SAM, the function of which is described in greater detail. We demonstrate that the confocal scanning principle is applied in both microscopes, although information about structure differs, depending on the method used.

Testosterone metabolism of fibroblasts grown from prostatic carcinoma, benign prostatic hyperplasia and skin fibroblasts.

The metabolism of [1,2,6,7-3H]testosterone was assessed in fibroblast monolayers derived from tissue of 5 prostates with benign hyperplasia (BPH), 4 prostates with carcinoma (PC), and 3 biopsy samples of skin, 2 nongenital skin (NG) and 1 genital skin. The following metabolites could be identified: androstanedione androstenedione, dihydrotestosterone, androsterone, epiandrosterone, androstane-3 alpha, 17 beta-diol and androstane-3 beta, 17 beta-diol. Testosterone was metabolized much more rapidly in fibroblasts originating from prostatic tissue than in fibroblasts derived from NG. A significantly higher formation of 5 alpha-androstanes and 3 alpha-hydroxysteroids could be observed in fibroblasts from BPH as compared to PC. 17-ketosteroid formation exceeded 5 alpha-androstane formation in BPH, whereas 5 alpha-reduction was the predominant pathway in fibroblasts grown from PC and NG. Since testosterone metabolism in fibroblasts of prostatic origin therefore resembles in many aspects that in whole prostatic tissue, fibroblasts grown from prostatic tissues might be a valuable tool for further investigation of the pathogenesis of human BPH and PC.