Rapid analysis of inner and outer bark composition of Southern Yellow Pine bark from industrial sources

Differences in bark chemistry between inner and outer bark are well known and may affect the suitability of various bark supplies for a particular application. Accordingly, there is a need for quality control protocols to assess variability and predict product yields. Southern yellow pine bark samples from two industrial sources were separated into inner and outer bark tissues and used to prepare both predetermined and random bark compositions for analysis. Near infrared (NIR) spectroscopy, coupled with multivariate analysis, was successfully used to develop models to predict relative amounts of inner bark. Application of mathematical treatments to the NIR data improved the calibration performance leading to improved predictions for the test samples. Results presented here show promise for the further development of this technique as a means to provide rapid and accurate predictions of the quality of bark obtainable from industrial sources.     

Backings and targets for chemical and nuclear studies of transactinides with TASCA

At GSI the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) was set up to investigate the chemical and physical properties of the heaviest elements making use of the highest beam intensities available [www.gsi.de/tasca; M. Schädel, D. Ackermann, A. Semchenkov, A. Türler, GSI Scientific Report 2005, GSI Report 2006-1, p. 262]. Appropriate backings and targets have to be developed.Conceivable backing materials are aluminium, titanium, and carbon. Aluminium backings and titanium backings in different thickness and from different companies are produced by cold rolling. Deposition by resistance heating is applied for carbon backings. For experiments in a chemically active atmosphere, beryllium has to be employed as backing, which is commercially available and produced by cold rolling.The task is to find the best material and thickness for backings to withstand two different processes: the electrodeposition, applied for the production of lanthanide and actinide targets at the Institut für Kernchemie, at the Universität Mainz [K. Eberhardt, et al., Contribution to this conference; D. Liebe, et al., Contribution to this conference], on the one hand, and deposition by thermal evaporation and sputtering on the other.We report on first tests with targets of uranium tetrafluoride (UF₄) and metallic uranium on various backings. In addition, the behaviour and durability will be described for the different backing–target combinations in a C-beam and in an Mg beam. For the upcoming beam time U, ²⁰⁸PbS, ¹⁴⁴Sm, ¹⁵⁴Sm, and Gd are required.     

Improvements in hierarchical symbolic tolerance and sensitivityanalysis

Sensitivity and tolerance analyses are important for circuit optimisation, but unfortunately very time consuming. In recent years new hierarchical symbolic methods have been developed for large linear circuits. These approaches make symbolic techniques a worthwhile alternative to classical numerical methods. Using the hierarchical symbolic approach, a new strategy is introduced which significantly reduces the computational expense of sensitivity and tolerance analyses compared to previous procedures     

Laser beam soldering – a new assembly technology for microoptical systems

Based on the development of an adhering and solderable layer system microoptical subsystems are joined by laser beam soldering. Fluxless processing with AuSn – solder (80/20 weight%) results in joints that are stable, leak-proof and that contain low mechanical stress. REM – investigations show that the joining area is homogenous. The paper will discuss a number of industrial applications.The work was partially supported by the German government in a BMBF / VDI-VDE project (Microoptical modules for the modular MST – MOBMO, Project Nr. 16SV2147) and by the Thuringian government (Soldering of microoptical and optoelectronical components – LOMO, Project Nr. 105023).     

Treatment of osteochondritis dissecans of the talus: use of the mosaicplasty technique--a preliminary report

A one-stage autogenous osteochondral grafting technique for the treatment of talar dome osteochondritis dissecans is described. Eleven patients with osteochondritis dissecans lesions, 10 mm or greater in diameter, were operated on using the mosaicplasty autogenous osteochondral transplantation technique. Osteochondral cylindrical grafts from the ipsilateral knee were delivered into the talar defect using specially designed tube chisels. These procedures were done by arthrotomy. With follow-up of 12 to 28 months (mean, 16 months), the patients returned to full activities and the results, using the Hannover scoring system, have been excellent.     

Characterization of long fiber thermoplastic/metal laminates

Long fiber thermoplastic (LFT) composite/metal laminate (LML) is a hybrid composite consisting of alternate layers of metals such as aluminum and an LFT composite, which combines advantages from both the constituents. The LFT/Al laminates (LMLs) were processed by compression molding and were characterized for their Young’s modulus, mechanical strength, and low-velocity impact (LVI) properties. The average values of specific elastic modulus and specific tensile strength were approximately 20 GPa/(gcm⁻³) and 108.5 MPa/(gcm⁻³), respectively. Failure mechanisms included delamination between LFT composite and Al, fiber fracture and pullout in LFT composite, and shear fracture of aluminum and LFT composite layers. Rule-of-mixtures (ROM) predictions of laminate properties in tension compared well with the experimental values. Specific perforation energy of the laminates determined by LVI tests was 7.58 J/(kgm⁻²), which is significantly greater than that of the LFT composite alone, 1.72 J/(kgm⁻²). Overall, the LML showed significant improvement in the properties as compared to the LFT composite.     

Biosynthesis of riboflavin: an unusual riboflavin synthase of Methanobacterium thermoautotrophicum

BACKGROUND: The aim of this study was to prospectively test whether the risk of bleeding complications in 212 consecutive outpatients treated with oral anticoagulants could be predicted by levels of endothelium-derived hemostatic variables. METHODS AND RESULTS: All bleeding complications were recorded during 5 years of follow-up; serious bleeding was defined as intracranial bleeding or hemorrhage causing death or necessitating hospitalization. The relationships of bleeding complications and plasma concentrations of tissue plasminogen activator, von Willebrand factor, and thrombomodulin, plasminogen activator inhibitor activity, and other possible risk factors were studied. Twenty-two patients suffered from bleeding complications during anticoagulant treatment; in 14 patients, these were serious. We found that the numbers both of serious hemorrhages and of total hemorrhages were significantly associated with increased levels of thrombomodulin. The number of bleeding episodes increased exponentially through quartiles one to four of the thrombomodulin distribution. CONCLUSIONS: Thrombomodulin concentrations in plasma are related to the risk of hemorrhage in patients treated with oral anticoagulants.     

Bioprinting Complex Cartilaginous Structures with Clinically Compliant Biomaterials

Bioprinting is an emerging technology for the fabrication of patient‐specific, anatomically complex tissues and organs. A novel bioink for printing cartilage grafts is developed based on two unmodified FDA‐compliant polysaccharides, gellan and alginate, combined with the clinical product BioCartilage (cartilage extracellular matrix particles). Cell‐friendly physical gelation of the bioink occurs in the presence of cations, which are delivered by co‐extrusion of a cation‐loaded transient support polymer to stabilize overhanging structures. Rheological properties of the bioink reveal optimal shear thinning and shear recovery properties for high‐fidelity bioprinting. Tensile testing of the bioprinted grafts reveals a strong, ductile material. As proof of concept, 3D auricular, nasal, meniscal, and vertebral disk grafts are printed based on computer tomography data or generic 3D models. Grafts after 8 weeks in vitro are scanned using magnetic resonance imaging and histological evaluation is performed. The bioink containing BioCartilage supports proliferation of chondrocytes and, in the presence of transforming growth factor beta‐3, supports strong deposition of cartilage matrix proteins. A clinically compliant bioprinting method is presented which yields patient‐specific cartilage grafts with good mechanical and biological properties. The versatile method can be used with any type of tissue particles to create tissue‐specific and bioactive scaffolds.     

Description and modeling of fiber orientation in injection molding of fiber reinforced thermoplastics

As mechanical properties of short fiber reinforced thermoplastic injected components depend on flow induced fiber orientation, there is considerable interest in validating and improving models which link the flow field and fiber orientations to mechanical properties. The present paper concerns firstly the observation and quantification of fiber orientation in a rectangular plaque with adjustable thickness and molded with 30 and 50 wt% short fiber reinforced polyarylamide. An automated 2D optical technique has been used to determine fiber orientations. A classical skin (with orientation parallel to the flow)-core (with orientation perpendicular) structure is observed for thick plaques (thickness greater than 3 mm) but the core region is fragmentary for thickness less than 1.7 mm. It is shown that the gate design and different levels of fiber interactions, due to different fiber concentrations, are responsible for these observations. Secondly, computer simulations of flow and fiber orientation are shown. The agreement with the actual data is good, except in the case of the core for thin plaques. The limitations that have to be resolved come not only from the standard fiber orientation equations, but also from the flow kinematics computation.