Bibliothek

Notizen: Ion cyclotron range of frequency (ICRF) heating experiments on the Large Helical Device (LHD) [O. Motojima et al. Fus. Eng. Des. 20, 3 (1993)] achieved significant advances during the third experimental campaign carried out in 1999. They showed significant results in two heating modes; these are modes of the ICH-sustained plasma with large plasma stored energy and the neutral beam injection (NBI) plasma under additional heating. A long-pulse operation of more than 1 minute was achieved at a level of 1 MW. The characteristics of the ICRF heated plasma are the same as those of the NBI heated plasma. The energy confinement time is longer than that of International Stellarator Scaling 95. Three keys to successful ICRF heating are as follows: (1) an increase in the magnetic field strength, (2) the employment of an inward shift of the magnetic axis, (3) the installation of actively cooled graphite plates along the divertor legs. Highly energetic protons accelerated by the ICRF electric field were experimentally observed in the energy range from 30 to 250 keV and the tail temperature depended on the energy balance between the wave heating and the electron drag. The transfer efficiency from the high energy ions to the bulk plasma was deduced from the increase in the energy confinement time due to the high energy ions in the lower density discharge, which agrees fairly well with the result obtained by the Monte Carlo simulation. The transfer efficiency is expected to be 95% at an electron density of more than ne=5.0×1019 m−3 even in the high power heating of 10 MW. The accumulation of impurities, e.g., FeXVI and OV was not observed in high rf power and long pulse operation. The well-defined divertor intrinsic to LHD is believed to be useful in reducing the impurity influx. © 2001 American Institute of Physics.

Notizen: We prepared a rod-like amphiphile with a molecular recognition end group, α-helical and hydrophobic poly(γ-methyl L-glutamate) (PMG) containing hydrophilic β-cyclodextrin (CyD) as an active end group (PMG-CyD), and formed its monolayer at the n-hexane/water interface. The interfacial pressure (π)-area (A) isotherms of the monolayer showed that α-helix rod of PMG-CyD could be vertically oriented at the oil/water interface, facing the hydrophilic terminal CyD group to the water phase, by increasing the interfacial concentration of the polypeptide. Under the condition 2-p-toludinyl-naphthalene-6-sulfonate (TNS), an intimate guest molecule for the CyD in water was introduced into the water phase beneath the monolayer. Within a minute the monolayer began to oscillate which could be monitored by the rhythmic response of the interfacial pressure of the monolayer. The oscillation continued over ten minutes and then terminated. The mode of the oscillation was found to change with time, i.e., the initial stage showing a periodic sharp reduction in the interfacial pressure (period I), the second stage having sharp increase in the π value (period II), and the last stage of irregular oscillations (period III). The Fourier analysis of each period also supported the three stages during the oscillatory process. It was also found that when the α-helix rod of PMG-CyD lay down in the monolayer, the guest TNS did not induce any changes in the interfacial tension. This nonlinear rhythmic interfacial phenomenon was explained in terms of the periodic movement of the PMG-CyD monolayer resulting from the binding and releasing of the guest TNS across the oil/water interface. © 1999 American Institute of Physics.

Notizen: Three-dimensionally aligned epitaxial (Pb,La)(Zr,Ti)O3/(La,Sr)2CuO4 multilayers were grown on SrTiO3 (100) single crystals by pulse laser deposition. A cube-on-cube epitaxial relationship of these multilayers was confirmed by the θ-2θ diffraction profile and the pole figure. The stability of their interfaces was confirmed by depth profiles and x-ray diffractometry of the as-deposited and the annealed multilayers having 100–300-A(ring)-thick (La,Sr)2CuO4 layers. The results suggest that the multilayers can be applied to the ferroelectric field-effect transistor. © 1995 American Institute of Physics.

Notizen: In maize, inbred lines are used for the production of hybrid varieties. Corn breeders and researchers have considered using haploids to develop inbred lines; however, this procedure has not been practically applied because of the inefficiency of chromosome doubling of maize haploid seedlings. In this report, a procedure has been developed to overcome this difficulty. Maize haploid seedlings obtained from eight different genotypes were treated with nitrous oxide gas (2 days at 600 kPa). Treatment at the six-leaf stage (flower primordia formation stage) significantly increased the occurrence of fertile sectors on both tassels and ears so that approximately half (44%) of the treated haploids produced kernels after self-pollination. In the control, only 11% of haploids produced selfed kernels owing to spontaneous chromosome doubling. A strong genotypic effect on the occurrence of fertile sectors after the treatment was observed. This procedure can be used for inbred line development in maize breeding programmes.

Notizen: Although it is known that the compositions of low-molecular weight glutenin subunits (LMW-GSs) are important factors for bread-making quality of wheat, it is still not clear which LMW-GSs confer improved bread-making quality and how those LMW-GSs interact with high-molecular weight (HMW) GSs. Using a hard red winter wheat line with good bread-making quality and a Japanese wheat cultivar with poor quality as well as their progeny we identified LMW-GSs associated with the bread-making quality. One such LMW-GS, KS2, which had a molecular weight of 42 kDa and was allelic to HS1, was associated with bread-making quality. Furthermore, by using four recombinant inbred lines with different HMW-GS and LMW-GS combinations, KS2 and HMW-GS 5+10 showed interaction effects on the bread-making quality. Two-dimensional polyacrylamide gel electrophoresis (Page) analysis showed that KS2 consists of two protein components and that HS1 is composed of three components. The N-terminal amino acid sequences of the five components were identical to the most frequently analysed sequence of LMW glutenin components.

Notizen: The rate of release of the soluble form of interleukin-2 receptor (soluble IL-2R) reflects T cell activation in vivo. Since T lymphocytes play a central role in respiratory allergic disorders, the measurement of serum levels of soluble IL-2R may be useful in analysing the disease state of allergic disorders. The study has aimed at investigating the seasonal changes in serum soluble IL-2R in 81 patients with seasonal allergic rhinitis due to Japanese cedar pollens, with special reference to the effect of anti-allergic pharmacotherapy and immunotherapy. Serum samples were obtained twice from each patient, before and during the pollen season, and all the serum samples were simultaneously used for determination of soluble IL-2R and cedar pollen-specific immunoglobin E (IgE). Seasonal elevation in soluble IL-2R was not associated with the good clinical outcome but was associated with the poor clinical outcome, irrespective of pharmacotherapy or immunotherapy. Additionally, successful immunotherapy suppressed seasonal elevation of serum soluble IL-2R more strongly than successful pharmacotherapy, and seasonal increase rates in soluble IL-2R were inversely correlated with the duration of immunotherapy. Seasonal increase rates in soluble IL-2R were significantly correlated with seasonal increase rates in specific IgE in both the medication group and the immunotherapy patients. These results may suggest that seasonal changes in serum soluble IL-2R may serve as an indicator for clinical outcome of seasonal allergic rhinitis, that the magnitude of T cell activation could affect specific IgE production, and that T cell activation could be gradually modulated as immunotherapy proceeds. In conclusion, seasonal changes in serum soluble IL-2R may serve as an objective indicator for clinical outcome of seasonal allergic rhinitis.

Notizen: This study was designed to determine seasonal changes in cytokines, soluble CD23 and specific IgE in the serum of patients with seasonal allergic rhinitis, and the effect of immunotherapy on these seasonal changes. Fifty-four patients with seasonal allergic rhinitis caused by Japanese cedar pollens were divided into a medication group and an immunotherapy group. The patients of the medication group were treated with non-sedating antihistamines alone during the pollen season. The patients of the immunotherapy group had been treated for variable periods (mean, 5.0 ± 3.2 years) with immunotherapy using Japanese cedar pollen antigens. Serum samples were collected before and during the pollen season from each patient, to determine specific IgE, interleukin-4 (IL-4), interferon-γ (IFN-γ) and soluble CD23 levels in serum. A significant increase in specific IgE and IL-4 and a significant decrease in IFN-γ were observed during the pollen season in the medication group. In contrast, in the immunotherapy group, none of specific IgE, IL-4 and IFN-γ was significantly changed following natural exposure to pollens. However, these effects were not significant in patients undergoing immunotherapy for 3 or fewer years. Seasonal rates of increase in specific IgE and IL-4 differed significantly between good responders and poor responders to immunotherapy, but seasonal rates of decrease in IFN-γ did not. A seasonal rate of increase in soluble CD23 was significantly correlated with a seasonal rate of increase in specific IgE, in both the medication and the immunotherapy groups. The seasonal rate of increase in soluble CD23 was significantly smaller in the good responders than in the poor responders to immunotherapy. In conclusion, pollen immunotherapy reduces the seasonal increase in specific IgE, IL-4 and soluble CD23 in serum, and in addition switches the seasonal preferential activation of Th-2 cells to reciprocal activation of Th-1 cells with treatment over several years. It is likely that the mechanisms responsible for the clinically beneficial effects of immunotherapy principally involve the modulation of Th-2 rather than Th-1 cytokines.

Notizen: A reproducible neuronal degeneration induced by nerve lesion in neonatal rats or mice provides a convenient in vivo assay for testing the survival-promoting activity of putative growth factors on motoneurons. The goal of this study was to compare the rescue effects of the four known neurotrophins [nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4)] and two of the cytokines [ciliary neurotrophic factor (CNTF) and leukaemia inhibitory factor (LIF)] in one particular experimental model of spinal motoneuron degeneration at two different survival times. The sciatic nerve was cut in neonatal rats and the factors were applied onto the nerve stump; bovine serum albumin was used in controls. Simultaneous application of the retrograde tracer fluoro-gold made it possible to count motoneurons specifically in the sciatic pool. One week after lesion, the neurotrophins BDNF, NT-3 and NT-4, but not NGF, equally enhanced motoneuron survival compared to controls; their effects were significantly better than those of the cytokines. However, the rescue from cell death was only transitory because a great number of the motoneurons died during the second week after nerve lesion. Additional BDNF and/or CNTF supplied by repeated subcutaneous injections (1 mg/ml) over 2 weeks could not prevent this delayed motoneuron loss. These results suggest that still other factors or alternative routes of administration may be required for permanent rescue of the lesioned immature motoneurons.

Notizen: Neuronal apoptosis inhibitory protein (NAIP), and human inhibitors of apoptosis 1 and 2 (HIAP1 and HIAP2) are three members of the mammalian family of antiapoptosis proteins called ‘inhibitors of apoptosis’ (IAP). These molecules can prevent apoptosis in vitro and the over-expression of NAIP can decrease ischemic damage in the hippocampus. The goal of our experiments was to determine whether administration of NAIP, HIAP1 and HAIP2 could rescue motoneurons following axotomy of a peripheral nerve. In young rats, an adenoviral gene transfer technique was used to deliver and express these proteins in motoneurons; a fluorescent tracer was simultaneously added as a means for quantitatively assessing the rescue of fluorescently labelled motoneurons in serial sections of the lumbar spinal cord. Control experiments using adenoviral vectors (adv) expressing the lacZ gene showed that 14% of the sciatic motoneuron pool could be transfected indicating the existence of a subpopulation of spinal motoneurons susceptible to this class of viral vectors. The administration of an adv-NAIP, adv-HIAP1 and adv-HIAP2 rescued 30–40% of motoneurons at one week after sciatic axotomy. The efficiency of these proteins was similar to that of two neurotrophic factors, ciliary neurotrophic factor and brain-derived neurotrophic factor, administrated by the same viral technique. The effect of the IAP proteins on motoneuron survival decreased with time but was still present after 4 weeks postaxotomy; the duration of the response was dependent upon the viral titre. These experiments demonstrate that IAP family proteins can prevent motoneuron cell death in vivo and may offer a new therapeutic approach for motoneuron diseases.