Suitable test structures for submicron ion beam analysis

For the precise determination of the sizes of submicron beam spots test structures with an excellent edge definition are required. For this purpose a semiconductor heterostructure consisting of an 1.62 μm GaInP epi-layer grown on (0 0 1) GaAs has been made, which provides atomically sharp edges for beam spot size measurements. Since the sample has been thinned down by standard transmission electron microscope (TEM) preparation techniques, it can be used for both PIXE and STIM. The sample has been investigated with a TEM and the ion nanoprobe LIPSION. A one-dimensional beam profile in the low current mode was determined by a STIM measurement using 2 MeV protons and yielded a FWHM of (41±4) nm, which is the smallest value reported so far for high energy nuclear micro- and nanoprobes. Furthermore we present nickel nanowhiskers produced at the GSI Darmstadt by electrochemical preparation of etched ion track membranes that have been used to obtain two-dimensional images of the shapes of submicron beam spots. For these measurements a scan over a single nickel nanowhisker having a diameter of 220 nm and a height of about 6 μm was performed.     

Development of active matrix LCD for use in high‐resolution adaptive headlights

Conventional adaptive driving beam headlamps are limited in achieving still higher quantities of switchable pixels by the number of LEDs and movable elements needed. In this paper, it is shown that by integrating an active matrix liquid crystal display module, it is possible to realize fully adaptive high‐resolution headlights without mechanical elements and a finite number of LED with 30 k switchable pixels.     

High Iron and Iron Household Protein Contents in Perineuronal Net-Ensheathed Neurons Ensure Energy Metabolism with Safe Iron Handling

A subpopulation of neurons is less vulnerable against iron-induced oxidative stress and neurodegeneration. A key feature of these neurons is a special extracellular matrix composition that forms a perineuronal net (PN). The PN has a high affinity to iron, which suggests an adapted iron sequestration and metabolism of the ensheathed neurons. Highly active, fast-firing neurons—which are often ensheathed by a PN—have a particular high metabolic demand, and therefore may have a higher need in iron. We hypothesize that PN-ensheathed neurons have a higher intracellular iron concentration and increased levels of iron proteins. Thus, analyses of cellular and regional iron and the iron proteins transferrin (Tf), Tf receptor 1 (TfR), ferritin H/L (FtH/FtL), metal transport protein 1 (MTP1 aka ferroportin), and divalent metal transporter 1 (DMT1) were performed on Wistar rats in the parietal cortex (PC), subiculum (SUB), red nucleus (RN), and substantia nigra (SNpr/SNpc). Neurons with a PN (PN⁺) have higher iron concentrations than neurons without a PN: PC 0.69 mM vs. 0.51 mM, SUB 0.84 mM vs. 0.69 mM, SN 0.71 mM vs. 0.63 mM (SNpr)/0.45 mM (SNpc). Intracellular Tf, TfR and MTP1 contents of PN⁺ neurons were consistently increased. The iron concentration of the PN itself is not increased. We also determined the percentage of PN⁺ neurons: PC 4%, SUB 5%, SNpr 45%, RN 86%. We conclude that PN⁺ neurons constitute a subpopulation of resilient pacemaker neurons characterized by a bustling iron metabolism and outstanding iron handling capabilities. These properties could contribute to the low vulnerability of PN⁺ neurons against iron-induced oxidative stress and degeneration.     

Chemische Synthese der Oligonucleotide dpG-A-T-A-T-C,dpG-A-T-C-T-T-T-T und dpT-T-T-C-A-T-C-A-T

Chemical Synthesis of the Oligonucleotides dpG-A-T-A-T-C, dpG-A-T-C-T-T-T-T and dpT-T-T-C-A-T-C-A-T For studies of some sequence dependent structural factors the oligonucleotides dpG-A-T-A-T-C, dpG-A-T-C-T-T-T-T and dpT-T-T-C-A-T-C-A-T were required. Their chemical synthesis is reported according to the diester method.     

Plea for an evaluation of beta hemolytic streptococcal tonsillitis: from diagnosis to treatment

The poor state of Aboriginal and Torres Strait Islander health has been documented in many ways, most obviously by comparing the relatively higher age-specific mortality and morbidity rates. This paper demonstrates the use of acute hospital separation data as a way to identify potential deficiencies in providing appropriate primary health care services for Aboriginal and Torres Strait Islander populations. It does so by using 'ambulatory sensitive conditions': those conditions (and procedures) for which high-quality appropriate primary health services deliverable under ideal circumstances are though to potentially reduce or eliminate the need for hospitalisation. Potential or realised access to primary care is not analysed directly using primary health service data. In this study, 1993-94 acute hospital separation data from NSW, Queensland, South Australia, Western Australia and the Northern Territory were used to calculate separation rates and odds ratios for Aboriginal and Torres Strait Islander and non-Aboriginal and Torres Strait Islander populations. Age-specific acute hospital separation rates for ambulatory sensitive conditions were 1.7 to 11 times higher for the Aboriginal and Torres Strait Islander populations studied. This supports clinical contentions that much Aboriginal and Torres Strait Islander morbidity and mortality is preventable and that further consideration is needed to service delivery reform at all levels in the health system and the distribution of funding.     

Calculation of losses in ferro- and ferrimagnetic materials basedon the modified Steinmetz equation

This paper discusses the influence of nonsinusoidal flux waveforms on the remagnetization losses in ferro- and ferrimagnetic materials of inductors, transformers, and electrical machines used in power electronic applications. The nonsinusoidal changes of flux originate from driving these devices by nonsinusoidal voltages and currents at different switching frequencies. A detailed examination of a dynamic hysteresis model shows that the physical origin of losses in magnetic material is the average rate of remagnetization rather than the remagnetization frequency. This principle leads to a modification of the most common calculation rule for magnetic core losses, i.e., to the “modified Steinmetz equation” (MSE). In the MSE, the remagnetization frequency is replaced by an equivalent frequency which is calculated from the average remagnetization rate. This approach allows, for the first time, the calculation of the losses in the time domain for arbitrary waveforms of flux while using the available set of parameters of the classical Steinmetz equation. DC premagnetization of the material, having a substantial influence on the losses, can also be included. Extensive measurements verify the MSE presented in this paper     

Highly Dissipative State of YBa2Cu3O7 Thin Films at Very Large Current Densities

Flux flow instabilities at high current densities have been recently reported to occur in high temperature superconductors. Such flux flow instabilities were already predicted by Larkin and Ovchinnikov. However, other mechanisms may possibly also account for this behaviour, as for instance hot spots or thermal instabilities. To investigate the mechanism at the origin of these instabilities, we have carried out detailed I- V experiments, using short current pulses, on YBCO thin films grown on sapphire substrates. When the current density exceeds 2-3 times the conventional critical current density, we observe an extremely fast transition from a low dissipative state into a highly dissipative state. We present some indications that this transition does not originate from temperature instabilities but is driven by the current.