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Notes: Magneto-oscillations due to a minority carrier two-dimensional electron gas (2DEG) in the base of a bipolar quantum well resonant tunneling transistor at liquid helium temperatures are reported, we believe, for the first time. These are attributed to a high-density 2DEG formed in the 20 nm undoped setback layer between the base and emitter. The 2DEG density has a nonmonotonic dependence on the emitter/base junction bias, increasing to a maximum at flatband conditions, then decreasing at higher bias. Associated lateral electron diffusion dominates recombination such that the current gain can increase 1000 times in a 6 T magnetic field. © 1996 American Institute of Physics.

Notes: [Auszug] First described in 1914 and commercialized in 1956, hemodialysis is used worldwide by about 0.8 million patients suffering from renal failure at a total cost of US $15 billion annually. Despite the success of hemodialysis at prolonging life, the morbidity and mortality associated with this ...

Notes: Summary An adequate increase of uterine blood flow throughout gestation is essential for uterine, placental and fetal growth. Maternal cardiovascular adaptation has to provide the uterine perfusion that is necessary to meet the requirements of the developing and growing fetus by providing transport of nutrients and oxygen to the placenta and the fetus. Thus uterine blood flow is inextricably linked to fetal growth and survival. Reductions of uterine blood flow can occur under acute or chronic conditions or in a combination of both. Chronic reductions of uterine blood flow can be observed in pregnancy induced hyertension (PIH), diabetes mellitus in pregnancy and intrauterine growth restriction (IUGR). Chronic restrictions in uterine blood flow will elicit a placental and fetal response in the form of growth adaptation to the reduced supply of oxygen and nutrients to the conceptus. If compensatory growth restriction reaches its limits intrauterine fetal distress can ensue.

Notes: Abstract Recently, close interactions have been described between the tumour necrosis factors alpha and beta (TNF-alpha and beta), interferon-gamma (INF-gamma) and intercellular adhesion molecule-1 (ICAM-1) in T-cell mediated immune activation. During the process of renal graft rejection, the properties of these cytokines to act as powerful stimulators of macrophages, to upregulate class II MHC expression and to stabilise cell-to-cell binding make them of great potential interest. The aim of the present study was to determine the plasma levels of each cytokine and soluble ICAM-1 in 16 renal allograft recipients. We examined plasmas of patients for the first 2 weeks after transplantation and correlated results with the clinical pattern of rejection. Our data suggest an immunopathologic involvement of TNF-alpha, TNF-beta and slCAM-1 in renal allograft rejection and showed that there was a significant elevation in plasma concentrations of these parameters 2 or 3 days prior to the diagnosis of clinical rejection. Rises in INF-gamma did not appear to be significant with regard to rejection as very high levels were found in patients showing no evidence of clinical rejection.

Notes: Summary Cysteamine bitartrate capsules (Cystagon) have been approved by the US Food and Drug Administration for use in patients with nephropathic cystinosis. Plasma cysteamine concentrations were virtually identical at various times following ingestion of either cysteamine hydrochloride or Cystagon capsules in 24 normal control subjects. A transfer study was done with eight cystinosis patients who had been receiving either cysteamine hydrochloride or phosphocysteamine for many years. The plasma cysteamine concentration was significantly higher 2h after Cystagon and the leukocyte cystine content was significantly lower at all times after Cystagon compared to older forms of the drug. These differences are probably the result of greater patient compliance in taking the capsules compared to the older, liquid forms of the drug. A new method for following the course of renal glomerular deterioration in diseases such as cystinosis has been published recently. This method was used to re-analyse data on the efficacy of cysteamine treatment and to re-analyse new data on treating cystinosis patients with either of two doses of cysteamine (1.30 g/m2 per day and 1.95 g/m2 per day). This new method agrees well with other methods and shows that both doses of drug are equally effective in maintaining glomerular function.

Notes: Abstract  The Saccharomyces cerevisiae temperature-sensitive mutants srm1-1, mtr1-2 and prp20-1 carry alleles of a gene encoding a homolog of mammalian RCC1. In order to identify a protein interacting with RCC1, a series of suppressors of the srm1-1 mutation were isolated as cold-sensitive mutants and one of the mutants, designated ded1-21, was found to be defective in the DED1 gene. The double mutant, srm1-1 ded1-21, could grow at 35° C, but not at 37° C. A revertant of srm1-1 ded1-21 that became able to grow at 37° C acquired another mutation in the SRM1 gene, indicating the tight relationship between SRM1 and DED1. In all the rcc1 - strains examined, the amount of mutated SRM1 proteins was reduced or not detectable at the nonpermissive temperature. While mutated SRM1 protein was stabilized in all of the rcc1 - strains by the ded1-21 mutation, the ded1-21 mutation suppressed both srm1-1 and mtr1-2, but not the prp20-1 mutation, contrary to the previous finding that overproduction of the S. cerevisiae Ran homolog GSP1 suppresses prp20-1, but not srm1-1 or mtr1-2.

Notes: Abstract The aurorae are the result of collisions with the atmosphere of energetic particles that have their origin in the solar wind, and reach the atmosphere after having undergone varying degrees of acceleration and redistribution within the Earth's magnetosphere. The global scale phenomenon represented by the aurorae therefore contains considerable information concerning the solar-terrestrial connection. For example, by correctly measuring specific auroral emissions, and with the aid of comprehensive models of the region, we can infer the total energy flux entering the atmosphere and the average energy of the particles causing these emissions. Furthermore, from these auroral emissions we can determine the ionospheric conductances that are part of the closing of the magnetospheric currents through the ionosphere, and from these we can in turn obtain the electric potentials and convective patterns that are an essential element to our understanding of the global magnetosphere-ionosphere-thermosphere-mesosphere. Simultaneously acquired images of the auroral oval and polar cap not only yield the temporal and spatial morphology from which we can infer activity indices, but in conjunction with simultaneous measurements made on spacecraft at other locations within the magnetosphere, allow us to map the various parts of the oval back to their source regions in the magnetosphere. This paper describes the Ultraviolet Imager for the Global Geospace Sciences portion of the International Solar-Terrestrial Physics program. The instrument operates in the far ultraviolet (FUV) and is capable of imaging the auroral oval regardless of whether it is sunlit or in darkness. The instrument has an 8° circular field of view and is located on a despun platform which permits simultaneous imaging of the entire oval for at least 9 hours of every 18 hour orbit. The three mirror, unobscured aperture, optical system (f/2.9) provides excellent imaging over this full field of view, yielding a per pixel angular resolution of 0.6 milliradians. Its FUV filters have been designed to allow accurate spectral separation of the features of interest, thus allowing quantitative interpretation of the images to provide the parameters mentioned above. The system has been designed to provide ten orders of magnitude blocking against longer wavelength (primarily visible) scattered sunlight, thus allowing the first imaging of key, spectrally resolved, FUV diagnostic features in the fully sunlit midday aurorae. The intensified-CCD detector has a nominal frame rate of 37 s, and the fast optical system has a noise equivalent signal within one frame of ∼ 10R. The instantaneous dynamic range is 〉1000 and can be positioned within an overall gain range of 104, allowing measurement of both the very weak polar cap emissions and the very bright aurora. The optical surfaces have been designed to be sufficiently smooth to permit this dynamic range to be utilized without the scattering of light from bright features into the weaker features. Finally, the data product can only be as good as the degree to which the instrument performance is characterized and calibrated. In the VUV, calibration of an an imager intended for quantitative studies is a task requiring some pioneering methods, but it is now possible to calibrate such an instrument over its focal plane to an accuracy of ±10%. In summary, very recent advances in optical, filter and detector technology have been exploited to produce an auroral imager to meet the ISTP objectives.