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  • 1
    Digitale Medien
    Digitale Medien
    The limits of resonant tunneling diode subharmonic mixer performance (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 1454-1458 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A theoretical analysis of the performance of subharmonically pumped mixers using resonant tunneling diodes is given based on the I-V curve of the latter. It is found that, in addition to the usual symmetry requirement, there are optimum positive and negative differential resistance values, as well as optimum current peak-to-valley ratios in this application. It is shown that, by carefully designing the diode, mixers can be built that will show positive conversion gain while operating in a harmonic mode.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.344420
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  • 2
    Digitale Medien
    Digitale Medien
    Experimental and numerical investigations of a hydrogen-assisted laser-induced materials transfer procedure (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 3537-3546 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We present investigations of the mechanisms of a laser-induced transfer technique, which can be used for the spatially selective deposition of materials such as Si. This transfer is effected by irradiating the backside of a hydrogenated amorphous silicon film, deposited on a transparent substrate with an excimer laser pulse. The resulting release and accumulation of hydrogen at the film/substrate interface propels the silicon onto an adjacent receptor wafer. Time-resolved infrared transmission measurements indicate that the amorphous film is melted by the laser pulse and breaks into droplets during ejection. These droplets travel towards the receptor substrate and coalesce upon arrival. The transfer velocity increases as a function of fluence, the rate of increase dropping noticeably around the full melt threshold of the film. At this fluence, the transfer velocity reaches values of around 1000 m/s for typical films. Atomic force microscopy reveals that films transferred below the full melt threshold only partially cover the receptor substrate, while uniform, well-adhering films, which can be smoothed by subsequent laser irradiation, are obtained above it. Transfer of hydrogen-free Si films, on the other hand, does not occur until much higher fluences. The dynamics of the process have been simulated using a semiquantitative numerical model. In this model, hydrogen released from the melt front is instantaneously accumulated at the interface with an initial kinetic energy given by the melting temperature of Si and the enthalpy of solution. The resulting pressure accelerates the Si film, the dynamics of which are modeled using Newtonian mechanics, and the gas cools adiabatically as its kinetic energy is converted to the film's momentum. The results of the calculations are in good agreement with the experimental data. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.372378
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  • 3
    Digitale Medien
    Digitale Medien
    Laser crystallization and structural characterization of hydrogenated amorphous silicon thin films (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 7914-7918 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The influence of hydrogen and film thickness on the excimer laser-induced crystallization of plasma-enhanced chemical-vapor deposition-grown hydrogenated amorphous silicon thin films has been studied. Films with hydrogen concentrations varying from 1 to 10 at. % have been crystallized using short pulses from a XeCl excimer laser, at fluences sufficient to induce melting throughout the thickness of the films. Dehydrogenation prior to laser exposure was necessary only for films having initial hydrogen concentrations larger than 5 at. %. The structural properties of the laser-crystallized materials were studied by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The AFM measurements revealed that films requiring no dehydrogenation are smoother after laser crystallization than those requiring laser dehydrogenation, and that the roughness of these films increases as a function of film thickness, although it could be reduced by multiple laser exposure. Smoother films (root-mean-square roughness ∼4.1 nm) were obtained by melting only the near-surface region of the film after the initial full melt exposure. TEM revealed that the laser-crystallized films consist of grains with sizes that are comparable to the film thickness. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.370607
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  • 4
    Digitale Medien
    Digitale Medien
    Spatially selective materials deposition by hydrogen-assisted laser-induced transfer (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 307-309 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Si and Al lines were deposited on glass substrates using a transfer technique based on the explosive release of hydrogen from a hydrogenated amorphous Si film melted by a laser pulse. The Si lines have a minimum width of 4.5 μm and are well defined, while the Al lines are wider and less uniform. Analysis of time-resolved infrared transmission signals reveals that the lines do not break into droplets upon ejection, in contrast to the behavior of unpatterned films. This difference is attributed to the escape of hydrogen through the sides of the molten lines into the adjacent material. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.126959
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  • 5
    Digitale Medien
    Digitale Medien
    Excimer laser crystallization and doping of silicon films on plastic substrates (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 342-344 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We report the pulsed laser recrystallization and doping of thin film amorphous silicon deposited on oxide-coated polyester substrates. Although our heat-flow simulation of the laser recrystallization process indicates that the plastic is briefly subjected to temperatures above its softening point, we see no evidence of damage to the plastic or film delamination from the substrate. Film grain size is found to vary up to ∼0.1 μm. Electrical characteristics obtained from simple strip line resistors and thin film transistors indicate that device-quality silicon films have been produced on an inexpensive flexible plastic substrate. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.118409
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  • 6
    Digitale Medien
    Digitale Medien
    Rapid healing of gastric ulcers with lansoprazole (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 8 (1994), S. 0 
    Details
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background: Lansoprazole is a new proton pump inhibitor which powerfully decreases acid secretion. Methods: We compared the efficacy and short-term safety of lansoprazole against ranitidine in the healing of gastric ulcer. This was a parallel group, comparative multicentre, prospectively randomized, double-blind study which included 250 patients with gastric ulcer, 219 of whom had follow-up endoscopic data. Results: Both lansoprazole 30 mg and 60 mg daily produced significantly more rapid healing of gastric ulcer than ranitidine 300 mg nightly with healing rates after 4 weeks of 78% (P 〈 0.05), 84% (P 〈 0.01) and 61%, respectively. After 8 weeks, the corresponding healing rates were 99%, 97% and 91% (P = 0.08). Symptom relief was similar for all treatment groups, but fewer antacids were used by patients receiving lansoprazole. Sixty-nine patients experienced 91 adverse events; the incidence, pattern and severity was similar across all three treatment groups. Conclusions: Lansoprazole 30 mg and 60 mg once daily had similar efficacy. Both were superior to ranitidine 300 mg nocte in healing gastric ulcer. The short-term safety profile of lansoprazole was similar to ranitidine. These data indicate that lansoprazole should be used at a dose of 30 mg once daily for the treatment of gastric ulcers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2036.1994.tb00281.x
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  • 7
    Digitale Medien
    Digitale Medien
    Electron spin resonance studies of spin-labeled polymers. III. Molecular weight dependence of segmental rotational correlation times of polystyrene in dilute solution (1973)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 77 (1973), S. 1635-1639 
    Details
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/j100632a008
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  • 8
    Digitale Medien
    Digitale Medien
    Adrenomedullin Acts in the Rat Paraventricular Nucleus to Decrease Blood Pressure (2001)
    Oxford, UK : Blackwell Science, Ltd
    Journal of neuroendocrinology 13 (2001), S. 0 
    Details
    ISSN: 1365-2826
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Adrenomedullin is a recently discovered peptide involved in the control of fluid and electrolyte homeostasis and cardiovascular function through peripheral and central nervous system actions. The present study was undertaken to examine the cardiovascular effects of adrenomedullin microinjection directly into the paraventricular nucleus (PVN). Microinjection of adrenomedullin into the PVN of urethane anaesthetized male Sprague-Dawley rats resulted in site-specific, repeatable decreases in blood pressure. These hypotensive effects were found to be dose related, and were not mediated by activation of calcitonin gene-related peptide receptors. These data suggest that adrenomedullin influences cardiovascular regulation through receptor mediated actions at the PVN of the hypothalamus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2826.2001.00657.x
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  • 9
    Digitale Medien
    Digitale Medien
    Porcine neural progenitors require commitment to the oligodendrocyte lineage prior to transplantation in order to achieve significant remyelination of demyelinated lesions in the adult CNS (2000)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 12 (2000), S. 0 
    Details
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Glial cell transplantation is a potential therapy for human demyelinating disease, though obtaining large numbers of oligodendrocyte precursors from nonrodent species is currently problematic. Culturing of multipotent neural progenitors may provide a solution to this problem, because these cells can be expanded in vitro whilst retaining the ability to differentiate into both neurons and glial cells. In order to investigate the myelinating capability of multipotent neural progenitors, we isolated cells from the porcine subventricular zone, a region rich in neural progenitors, and transplanted them into areas of persistent demyelination in the spinal cord of immunosuppressed rats, created by the injection of ethidium bromide and subsequent exposure to 40 Gy X-irradiation. Porcine SVZ cells were transplanted either within 12 h of isolation or after 7 days in B104-conditioned medium. Freshly isolated cells did not mature into myelinating oligodendrocytes following transplantation and instead remained as clusters of undifferentiated progenitors. However, cells exposed to B104-conditioned medium prior to transplantation were able to effect complete remyelination of the demyelinated axons. This suggests that neural progenitors must be manipulated in vitro for commitment to the oligodendrocyte lineage prior to transplantation if significant remyelination is to be achieved.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1460-9568.2000.00137.x
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  • 10
    Digitale Medien
    Digitale Medien
    Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta-analysis (2005)
    Oxford, UK : Munksgaard International Publishers
    Scandinavian journal of medicine & science in sports 15 (2005), S. 0 
    Details
    ISSN: 1600-0838
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Sportwissenschaft
    Notizen: The purpose of this study was to use the meta-analytic approach to examine the effects of caffeine ingestion on ratings of perceived exertion (RPE). Twenty-one studies with 109 effect sizes (ESs) met the inclusion criteria. Coding incorporated RPE scores obtained both during constant load exercise (n=89) and upon termination of exhausting exercise (n=20). In addition, when reported, the exercise performance ES was also computed (n=16). In comparison to placebo, caffeine reduced RPE during exercise by 5.6% (95% CI (confidence interval), −4.5% to −6.7%), with an equivalent RPE ES of −0.47 (95% CI, −0.35 to −0.59). These values were significantly greater (P〈0.05) than RPE obtained at the end of exercise (RPE % change, 0.01%; 95% CI, −1.9 to 2.0%; RPE ES, 0.00, 95% CI, −0.17 to 0.17). In addition, caffeine improved exercise performance by 11.2% (95% CI; 4.6–17.8%). Regression analysis revealed that RPE obtained during exercise could account for ∼29% of the variance in the improvement in exercise performance. The results demonstrate that caffeine reduces RPE during exercise and this may partly explain the subsequent ergogenic effects of caffeine on performance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1600-0838.2005.00445.x
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