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  • 1
    Digitale Medien
    Digitale Medien
    Mechanism of orientation of stimulating currents in magnetic brain stimulation (abstract) : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 6023-6023 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We made a functional map of the human motor cortex related to the hand and foot areas by stimulating the human brain with a focused magnetic pulse. We observed that each functional area in the cortex has an optimum direction for which stimulating currents can produce neural excitation. The present report focuses on the mechanism which is responsible for producing this anisotropic response to brain stimulation. We first obtained a functional map of the brain related to the left ADM (abductor digiti minimi muscles). When the stimulating currents were aligned in the direction from the left to the right hemisphere, clear EMG (electromyographic) responses were obtained only from the left ADM to magnetic stimulation of both hemisphere. When the stimulating currents were aligned in the direction from the right to the left hemisphere, clear EMG signals were obtained only from the right ADM to magnetic stimulation of both hemisphere. The functional maps of the brain were sensitive to changes in the direction of the stimulating currents. To explain the phenomena obtained in the experiments, we developed a model of neural excitation elicited by magnetic stimulation. When eddy currents which are induced by pulsed magnetic fields flow in the direction from soma to the distal part of neural fiber, depolarized area in the distal part are excited, and the membrane excitation propagates along the nerve fiber. In contrast, when the induced currents flow in the direction from the distal part to soma, hyperpolarized parts block or inhibit neural excitation even if the depolarized parts near the soma can be excited. The model explains our observation that the orientation of the induced current vectors reflect both the functional and anatomical organization of the neural fibers in the brain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.347801
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  • 2
    Digitale Medien
    Digitale Medien
    Foucault imaging of superconducting fluxons (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 4096-4103 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The Foucault method, one of the classical Lorentz microscopy techniques, is here investigated in order to demonstrate its applicability to in-focus observations of superconducting fluxons. As the deflections involved are of the order of 10−5−10−6 rad, low-angle techniques, high brightness, coherent illumination, and a low aberration magnetic stage are needed. The first experimental results are presented and discussed in relation with a theoretical model for the fluxon which allows the interpretation of the main features of the observed patterns. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.370317
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  • 3
    Digitale Medien
    Digitale Medien
    Construction and beam experiment of a compact storage ring at MELCO : Proceedings of the 5th international conference on synchrotron radiation instrumentation (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 1968-1970 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A compact storage ring has been developed for industrial research such as x-ray lithography and material analysis. This machine is of a racetrack type with two superconducting bending magnets and only two normal conducting quadrupole magnets. The circumference is as short as 9.2 m. One quadrupole magnet per cell contributes to making the smaller machine. The injector is a synchrotron, and a full energy injection of 600 MeV is performed. The bending magnets excite a field of 3.5 T, and are operated in a persistent current mode. A decrease in a coil current is ΔI/I〈3×10−3/year. The helium consumption is as low as 2 l/h for two magnets. An iron shield of the magnet decreases a leakage flux to a terrestrial level at a point 3 m from the magnet. A beam current of 380 mA has been stored with no beam instability in spite of there being no correction of the chromaticities. Beam emittances were obtained from measured beam sizes and were in good agreement with calculated values. The coupling coefficient εy/εx is calculated as around 0.04. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1145772
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  • 4
    Digitale Medien
    Digitale Medien
    Gonadotropin-releasing hormone stimulates phospholipase C but not protein phosphorylation/dephosphorylation in plasma membrane from human epithelial ovarian cancer (1993)
    238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 3 (1993), S. 0 
    Details
    ISSN: 1525-1438
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In view of advances in treatment of certain hormone-dependent cancers with analogues of gonadotropin-releasing hormone (Gn-RH), this study was undertaken to establish the signal transduction events interacting with Gn-RH receptor in a cell-free system prepared from human ovarian mucinous cystadenocarcinoma samples. A high affinity specific binding (Kd=8 × 10−9 M) of [3H] Gn-RH was demonstrated in two from two plasma membrane preparations. Gn-RH showed no effects on the rate of protein phosphorylation from [γ-32P] adenosine triphosphate in the plasma membrane preparations. On the other hand, incubation of plasma membrane isolated form [3H]inositol-labeled specimens with Gn-RH in the presence of guanosine thiotriphosphate resulted in the rapid production of inositol phosphates. The Gn-RH effects was concentration-dependent, and half-maximal activation occurred with 1–3 nm Gn-RH. The Gn-RH-stimulated membrane event was observed in all plasma membrane isolations tested, but not in those from uterine endometrial carcinoma of a given case. These results provide the first direct evidence that Gn-RH receptor is coupled to phosphoinositide hydrolysis but not to certain membrane protein phosphorylation/dephosphorylation in ovarian carcinoma plasma membrane. Though the functional role of this event in human ovarian cancer is still obscure, it might be part of a possible point of attack for therapeutic approaches using Gn-RH analogues in this malignancy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1525-1438.1993.03050311.x
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  • 5
    Digitale Medien
    Digitale Medien
    Selective reduction by isolation rearing of 5-HT1A receptor-mediated dopamine release in vivo in the frontal cortex of mice (2002)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 83 (2002), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Serotonin (5-HT)1A receptors modulate in vivo release of brain monoaminergic neurotransmitters which may be involved in isolation-induced aggressive behavior. The present study examined the effect of isolation rearing on the 5-HT1A receptor-mediated modulation of dopamine (DA), 5-HT and noradrenaline (NA) release in the frontal cortex of mice. The selective 5-HT1A receptor agonist (S)-5-{3-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy}-1,3-benzodioxole HCl (MKC-242) increased the release of DA and NA and decreased the release of 5-HT in the frontal cortex of mice. The effect of MKC-242 on DA release was significantly less in isolation-reared mice than in group-reared mice, while effects of the drug on NA and 5-HT release did not differ between both groups. The effect of the other 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin on cortical DA release was also less in isolation-reared mice than in group-reared mice, and that of the drug on cortical 5-HT release did not differ between both groups. In contrast to MKC-242-induced DA release, amphetamine-induced increase in cortical DA release in vivo was greater in isolation-reared mice. The present findings suggest that isolation rearing enhances the activity of cortical dopaminergic neurons and reduces selectively the 5-HT1A receptor-mediated release of DA in the cortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1471-4159.2002.01128.x
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  • 6
    Digitale Medien
    Digitale Medien
    High-resolution observation of magnetization processes in 2 μm × 2 μm × 0.04 μm permalloy particles : The 40th annual conference on magnetism and magnetic materials (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5075-5077 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The magnetization process in an array of 2 μm × 2 μm × 0.04 μm permalloy particles fabricated on a 100 nm carbon membrane was investigated by means of high-resolution Lorentz microscopy and electron holography in magnetic fields parallel and perpendicular to the film surface. For perpendicular fields, the magnetization reversal was found to begin with the nucleation of a vortex which gradually transformed into a closure domain configuration. At the remanent state, the flux closure was achieved with the generation of a new type of doubled domain wall. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.361921
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  • 7
    Digitale Medien
    Digitale Medien
    Thermal behavior of deep levels correlated with iron in silicon metal-oxide-semiconductor structure (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2199-2201 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Thermal behavior of deep levels correlated with iron in Si MOS (metal-oxide-semiconductor) structure has been studied by isothermal capacitance transient spectroscopy. As a result, it is shown that interstitial iron scarcely affects the interface trap (Nt) of MOS structure. This is made clear by measuring Nt of Si MOS diodes containing iron impurity, the interstitial component of which is controlled by low temperature annealings. In addition, the low temperature (400 °C) annealing decreases interstitial iron concentration as well as interface trap density. This phenomenon is very lucky for Si MOS devices. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.359543
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  • 8
    Digitale Medien
    Digitale Medien
    Two-dimensional spectral distribution of photoluminescence from porous silicon (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6434-6443 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The two-dimensional spectral distribution of photoluminescence (PL) was analyzed for p-type and n-type porous silicon (PS) prepared under different illumination conditions. In the p-type PS fabricated under strong illumination, the peak position of PL distribution in the depth direction moves inside the PS as the wavelength becomes longer. On the other hand, the PS prepared in the dark has an intensity peak of longer wavelength near surface. In the n-type PS formed under illumination, PL intensity has a peak near the PS surface and the peak position of the PL intensity does not move much. The difference between p-type and n-type PS suggests that the penetration depth of the light becomes greater as the PS layer grows and thus the effect of illumination may extend far inside p-type PS. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.363663
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  • 9
    Digitale Medien
    Digitale Medien
    Two-dimensional intensity distribution of photoluminescence from porous silicon (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 1743-1748 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Photoluminescent (PL) intensity-distribution images and PL spectra of porous silicon (PS) have been analyzed. The PL intensity of the top surface of n-type PS is nearly uniform and is dependent upon illumination conditions during anodization. N-type PS fabricated under high power illumination has the peak of the PL spectra at shorter wavelength than that under low power illumination. On the other hand, the peak position of the PL spectra of n-type PS does not shift significantly with change of current density. The PL intensity of n-type PS is the maximum at the surface and decreases exponentially towards the Si substrate, P-type PS has a relatively broad intensity peak within the PS layer with or without illumination during fabrication. These results suggest that illumination during fabrication plays a role in the PL light emission of PS. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.362985
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  • 10
    Digitale Medien
    Digitale Medien
    Increase in choline acetyltransferase activity in the nervous system of adult frogs awakened from hibernation (1979)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 32 (1979), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1979.tb02304.x
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