Organs from animals for man

In the following review some of the problems of xenotransplantation shall be discussed, based on the few experimental data available so far and on reports in the literature describing investigations which may be of importance for xenotransplantation. The impact of gravity on the upright posture of man versus almost all other mammals, the dysfunction between enzymes and hormones in different species and the lack of interactions between interleukins, cytokines and vasoactive substances will be taken into consideration. The question must be asked whether different levels of carrier molecules or serum proteins play a role in the physiological network. Even though the development of transgenic animals or other imaginative manipulations may lead to the acceptance of any type of xenografted organ, it has to be established for how long the products of the xenografts are able to act in the multifactorial orchestra. We are far from understanding xenogeneic molecular mechanisms involved in toxicity, necrosis and apoptosis or even reperfusion injury and ischemia in addition to the immediate mechanisms of the hyperacute xenogeneic rejection. Here, cell adhesion, blood clotting and vasomotion collide and bring micro- and macrocirculation to a standstill. All types of xenogeneic immunological mechanisms studied so far were found to have a more serious impact than those seen in allogeneic transplantation. In addition we are now only beginning to understand that so-called immunological parameters in allogeneic mechanisms act also in a true physiological manner in the xenogeneic situation. These molecular mechanisms occur behind the curtain of hyperacute, accelerated, acute or chronic xenograft rejection of which only some folds have been lifted to allow glimpses of part of the total scene. Other obstacles are likely to arise when long-term survival is achieved. These obstacles include retroviral infections, transfer of prions and severe side effects of the massive immunosuppression which will be needed. Moral, ethical and religious concerns are under debate and the species-specific production of proteins of the foreign donor species developed for clinical use suddenly appears to be a greater problem than anticipated.     

A Novel internally heated Au/TiO2 carbon-carbon composite structured reactor for low-temperature CO oxidation

A compact, internally heated, catalytic reactor is demonstrated for the low-temperature oxidation of carbon monoxide. Carbon nanofibres were grown on carbon felt and used as a support material for Au/TiO₂ catalysts. The carbon composite plays two roles; as a support material for the catalyst and for providing heat to the reaction by the Joule effect. The internal heating offers a stable reactor system with quick temperature response at relatively low energy input. Comparison between external and internal heating shows higher conversion of CO in the low-temperature range when using internal heating. The Au/TiO₂ catalyst supported on the carbon-carbon composite shows good stability at 250°C.     

Rechtliche Löschvorschriften

Zusammenfassung  Personenbezogene Daten müssen gel?scht werden, wenn sie für die weiteren Gesch?ftprozesse der Unternehmen nicht mehr erforderlich sind und auch gesetzliche Aufbewahrungsfristen der L?schung nicht im Wege stehen. In der Praxis wird dieser L?schpflicht allerdings nur zurückhaltend Rechnung getragen. Der Beitrag begründet das Erfordernis konsequenten L?schens und will dazu motivieren, den gesetzlich vorgegebenen L?schpflichten durch ein L?schkonzept Rechnung zu tragen. Reinhard Fraenkel ist nach verschiedenen T?tigkeiten in der Industrie seit 1994 als Rechtsanwalt in Gütersloh t?tig. Zu seinen Arbeitsschwerpunkten z?hlt das Datenschutzrecht. Seit August 2004 ist er externer Datenschutzbeauftragter der Toll Collect GmbH. Dr. Volker Hammer ist Consultant der Secorvo GmbH. Seit Mitte 2003 unterstützt er die Toll Collect GmbH in verschiedenen Datenschutz-Projekten. Weitere Arbeitsschwerpunkte sind Public Key Infrastrukturen und kritische IT-Infrastrukturen     

Network analysis of the modes of two-dimensionalgrating-surface-emitting diode laser arrays

The modes and threshold gain characteristics of two-dimensional grating-surface-emitting diode laser arrays that are evanescently coupled in the lateral direction and mutually injection coupled in the longitudinal direction are analyzed. The ratio of the grating transmissivity to reflectivity is found to be a critical parameter in obtaining uniform power distribution inside the array. Good qualitative agreement between the theory and experimentally measured near-field patterns and threshold currents is obtained     

Satellite-derived irradiance statistics for Africa

Hourly images registered by the Meteosat satellite are used to derive the global irradiance at ground level. Keeping almost the full spatial information of the original images, maps of irradiance characteristics for Africa are derived with a resolution of approx. 10 × 10 km². Monthly irradiance conditions are characterized by means and standard deviations of daily sums and the irradiance of specific daytime hours. The data also allow for the extraction of irradiance time series for specific sites. In addition, the analysis of the spatial structure of the satellite-derived irradiance fields is used to identify regions in which the radiation characteristics call for special attention.     

Life cycle environmental assessment of lithium-ion and nickel metal hydride batteries for plug-in hybrid and battery electric vehicles

This study presents the life cycle assessment (LCA) of three batteries for plug-in hybrid and full performance battery electric vehicles. A transparent life cycle inventory (LCI) was compiled in a component-wise manner for nickel metal hydride (NiMH), nickel cobalt manganese lithium-ion (NCM), and iron phosphate lithium-ion (LFP) batteries. The battery systems were investigated with a functional unit based on energy storage, and environmental impacts were analyzed using midpoint indicators. On a per-storage basis, the NiMH technology was found to have the highest environmental impact, followed by NCM and then LFP, for all categories considered except ozone depletion potential. We found higher life cycle global warming emissions than have been previously reported. Detailed contribution and structural path analyses allowed for the identification of the different processes and value-chains most directly responsible for these emissions. This article contributes a public and detailed inventory, which can be easily be adapted to any powertrain, along with readily usable environmental performance assessments.     

Sensor based registration and stacking of electronic substratelayers

This sensor-based approach for registration and stacking of electronic substrate sublaminates replaces pin-in-slot methods, yet does not require accurate automation equipment. Tests of a pilot workcell for this approach showed that the contact holes were consistently aligned to 2.5 μm (3σ), more than ten times better than the traditional mechanical method     

Improved coordination of care for elderly patients

VUSN will survive to enter the next millennium as a private university school of nursing only if it is a cutting-edge risk taker that is willing to explore new areas of teaching, practice, and research; otherwise, the expense and support of a private school of nursing cannot be justified.     

Near-infrared heavy-atom-modified fluorescent dyes for base-calling in DNA-sequencing applications using temporal discrimination

A series of near-IR fluorescent dyes were prepared which contained an intramolecular heavy atom for altering the fluorescence lifetimes to produce a set of probes appropriate for base-calling in a single-lane DNA sequencing format. The heavy-atom modification consisted of an intramolecular halogen situated on a remote section of the chromophore in order to minimize the perturbation on the lifetimes and fluorescence quantum yields. In addition, the dye series possessed an isothiocyanate functional group to allow facile attachment to sequencing primers. The unconjugated dyes showed similar absorption and emission maxima (lambda abs = 765-768 nm; lambda em = 794-798 nm) as well as fluorescence quantum yields that were invariant, within experimental error, with the heavy atom. However, the lifetimes of these dyes were found to vary with the identity of the halogen substitution (I, tau f = 947 ps; F, tau f = 843 ps, measured in methanol), with an average variation within the dye series of 35 ps. The spectroscopic properties of the free dyes and the dyes conjugated to sequencing primers on the 5'-end of the oligonucleotide were determined in a DNA-sequencing matrix (denaturing gels containing formamide). The results indicated slight differences in the fluorescence properties of the free dyes compared to those of the dye/ primer conjugates in this particular matrix. Inspection of the ground-state absorption spectra showed significant aggregation for the free dyes in this solution, but the conjugated dyes exhibited no sign of aggregation due to the highly anionic nature of the oligonucleotide. The fluorescence lifetimes of the dye/primer conjugates demonstrated lifetimes which ranged from 735 to 889 ps, with an average variation of 51 ps, an adequate difference to allow facile discrimination of these dyes in DNA-sequencing conditions. In addition, the free solution electrophoretic mobilities of the native heavy-atom-modified dyes were found to be very similar. When the dye/primer conjugates were electrophoresed in a cross-linked polyacrylamide gel electrophoresis capillary column, they comigrated, indicating that, in single-lane sequencing applications, when utilizing these dyes, no postrun corrections would be required to correct for dye-dependent mobility shifts.