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  • 1
    Digitale Medien
    Digitale Medien
    Far-field characteristics of mid-infrared angled-grating distributed feedback lasers (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 6997-7005 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The far-field emission characteristics of mid-infrared angled-grating distributed-feedback (α-DFB) lasers with W active regions are calculated using a self-consistent beam-propagation formalism that is more general than previous analyses. The theoretical projections are compared with the results of an experimental study of optically pumped α-DFB devices. Near-diffraction-limited beam quality is obtained both theoretically and experimentally for pump stripes ≤50 μm wide. While simulations employing the theoretical linewidth enhancement factor of 1.7 for the homogeneously-broadened W-laser gain spectrum predict that the good beam quality should be retained for stripes as wide as (approximate)200 μm, the data indicate a much more rapid degradation. That finding can be reproduced only by assuming that inhomogeneous broadening increases the structure's linewidth enhancement factor to (approximate)5. The experiments and theory also yield a steering of the output beam to off-normal angles as large as 6° when temperature tuning shifts the gain peak away from the grating resonance. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1326858
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  • 2
    Digitale Medien
    Digitale Medien
    Continuous-wave operation of λ=3.25 μm broadened-waveguide W quantum-well diode lasers up to T=195 K (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 256-258 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Mid-infrared (λ=3.25 μm) broadened-waveguide diode lasers with active regions consisting of 5 type-II "W" quantum wells operated in continuous-wave (cw) mode up to 195 K. At 78 K, the threshold current density was 63 A/cm2, and up to 140 mW of cw output power was generated. A second structure with ten quantum wells operated up to 310 K in pulsed mode. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.125739
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  • 3
    Digitale Medien
    Digitale Medien
    Mid-infrared angled-grating distributed feedback laser (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3164-3166 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We report near-diffraction-limited output from an angled-grating distributed feedback type-II W laser emitting near 3.4 μm. For pulsed optical pumping of a 50-μm-wide stripe at 78 K, the far-field beam divergence angle was only 1.4°. The slope efficiency was 64% of that for a conventional Fabry–Pérot laser on the same bar. However, the spectral linewidth decreased by only a factor of 2. The beam quality was substantially better than that for the Fabry–Pérot laser out to stripe widths of at least 800 μm. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.126617
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  • 4
    Digitale Medien
    Digitale Medien
    Convergence and Divergence in Development (1975)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Sociology 1 (1975), S. 223-246 
    Details
    ISSN: 0360-0572
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Sociologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.so.01.080175.001255
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  • 5
    Digitale Medien
    Digitale Medien
    Distribution of metals during digestion by cutthroat trout fed benthic invertebrates contaminated in the Clark Fork River, Montana and the Coeur d'Alene River, Idaho, U.S.A., and fed artificially contaminated Artemia (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 56 (2000), S. 0 
    Details
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The concentrations of essential amino acids in three, undigested invertebrate diets collected from the Clark Fork River (CFR) for cutthroat trout were similar to each other, but were c. 25–75% less than Artemia that were exposed to a mixture of arsenic, copper, cadmium, lead and zinc in the laboratory. The Artemia diet appeared less palatable and the texture, quantity and appearance of the intestinal contents differed between fish fed the Artemia and CFR diets. The Pb% in the fluid fraction of the intestinal contents was greater for the Artemia (29%) than for the CFR diets (10–17%), and the Cu% in the amino acid plus metal fraction of the intestinal contents was greater for the Artemia (78%) than for two of the three CFR diets (67% and 70%). Intestinal contents of fish fed invertebrate diets collected from various sites on the Coeur d'Alene River (CDA), Idaho, were similar in texture, quantity, and appearance. For fish fed the CDA diets, differences in the distribution of metals among fractions of the digestive fluids appeared to be related to concentrations of metals in the invertebrate diets. Pb% was lowest of all metals in the fluid portion of the intestinal contents. However, 〉80% of all metals in the hind gut were associated with the particulate fraction where they may still be available for uptake through pinocytosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1095-8649.2000.tb02093.x
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  • 6
    Digitale Medien
    Digitale Medien
    193. Bypass-Chirurgie der Coronararterien bei 95 Patienten über dem 70. Lebensjahr (1975)
    Springer
    Langenbeck's archives of surgery 339 (1975), S. 720-720 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Aortocoronary bypass surgery ; Aorto-coronare Bypass-Chirurgie
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Von den bis Juli 1974 am Texas Heart Institute durchgeführten 3780 aorto-coronaren Bypass-Operationen waren 95 Patienten 70 Jahre oder älter. Die anfänglich hohe Operationsmortalität in dieser Altersgruppe mit 27% stand in klarem Gegensatz zur Gesamtmortalität von 7,1% und konnte im letzten Jahr - hauptsächlich auf Grund von Verbesserungen in der Operationstechnik - von 27 % auf 4,8 % reduziert werden. Damit kann auch beim alten Patienten, im Einzelfall, eine coronare Bypass-Operation als Behandlungsmöglichkeit ins Auge gefaßt werden.
    Notizen: Summary From October 1969 through June 1974, 95 patients over 70 years of age underwent aortocoronary bypass at the Texas Heart Institute. The primary indication for surgery was severe angina, which was present in 88 patients. The mean coronary artery score was 9.51. Improvements in surgical technique are responsible for a reduction in the hospital mortality from 22.1 percent in all 95 patients to only 4.8 percent in the 21 patients operated upon during the first 6 months of 1974.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01257673
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  • 7
    Digitale Medien
    Digitale Medien
    196. Aktive bakterielle Endokarditis und ihre Klappenkomplikationen -Chirurgische Ergebnisse bei 225 Patienten (1975)
    Springer
    Langenbeck's archives of surgery 339 (1975), S. 722-722 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Endocarditis ; Valvular complications ; Endokarditis ; Herzklappenprothesen ; Komplikationen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 225 Patienten wurden wegen aktiver bakterieller Endokarditis oder der Klappenkomplikationen operiert. Die Frühmortalität betrug 12%. Bei 16 Patienten kam es zur Prothesendehiszenz - davon überlebten 6 Patienten die notfall mäßige Reoperation und 7 Patienten verstarben -, eine Indikation zu ausgedehnter Resektion des erkrankten Gewebes. Das mittlere Operationsalter betrug 43 Jahre. Auf Grund der vorliegenden Daten darf angenommen werden, daß die Mortalität durch eine kombinierte klappenchirurgische- und Coronararterien-Operation - falls indiziert-weiter gesenkt werden kann.
    Notizen: Summary Between 1959 and 1973, 225 patients were operated on because of active bacterial endocarditis or its valvular complications. The hospital mortality was 12 percent and 60 patients died an average of 2 years after the operation. Seven early deaths occurred among 16 cases of acute dehiscence of the prosthetic valve-an indication for extensive resection of all diseased tissues. The average age was 43 years and there were 21 deaths due to myocardial infarction. The authors believe that the operative mortality can be further reduced through combined valvular and coronary artery surgery where this is indicated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01257676
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  • 8
    Digitale Medien
    Digitale Medien
    Micromachined, Polyimide-Based Devices for Flexible Neural Interfaces (2000)
    Springer
    Biomedical microdevices 2 (2000), S. 283-294 
    Details
    ISSN: 1572-8781
    Schlagwort(e): neural prostheses ; MEMS ; polyimide ; electrical stimulation ; implant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract Micromachining technologies were established to fabricate microelectrode arrays and devices for interfacing parts of the central or peripheral nervous system in case of neuronal disorders. The devices were part of a neural prosthesis that allows simultaneous multichannel recording and multisite stimulation of neurons. Overcoming the brittle mechanics of silicon, we established a process technology to fabricate light-weighted and highly flexible polyimide based devices. Concerning the challenging housing demands close to the nerve to prevent mechanical induced nerve traumatization, we integrated interconnects to decouple the nerve interface from plugs and signal processing electronics. Hybrid integration with a new assembling technique—the MicroFlex interconnection (MFI)—has been applied for the connection of the flexible microsystems to silicon microelectronics. In this paper, we present different shapes and applications of the flexible electrodes: sieve electrodes for regeneration studies, cuff electrodes for interfacing peripheral nerves, and a retina implant for ganglion cell stimulation. The discussion is focused on electrode and material properties and the hybrid assembly of a fully implantable neural prosthesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009955222114
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  • 9
    Digitale Medien
    Digitale Medien
    Evidence for deformation in 113-116Cd isotopes (2000)
    Springer
    The European physical journal 7 (2000), S. 347-353 
    Details
    ISSN: 1434-601X
    Schlagwort(e): PACS: 21.60.Ev Collective models – 21.60.Jz Hartree-Fock – 23.20.Lv Gamma transitions and level energies – 25.70.Jj Fusion and fusion-fission reactions – 27.60.+j 90 ≤ A ≤ 149
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract: High-spin states in 113-116Cd have been investigated with the fusion-fission reaction 28Si +176Yb at 145 〉 MeV. The experiment has been performed with the Eurogam2 array. New rotational bands based on two quasi-particle states have been observed for even-even cadmium isotopes. A new level scheme based on the 11/2− isomeric state is proposed for 115Cd and the one of 113Cd has been extended to spin (31/2−). The decoupled bands identified in both odd-A nuclei are interpreted as being built upon a low-Ωh11/2 quasi-neutron configuration. Microscopic Hartree-Fock + BCS calculations confirm the prolate deformation in this mass region especially for the odd cadmium isotopes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00013614
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  • 10
    Digitale Medien
    Digitale Medien
    Physiologische Auswirkungen einer Zerstörung der Tip-Links kochleärer Haarsinneszellen Bedeutung für die lärminduzierte Schädigung des Gehörs (2000)
    Springer
    HNO 48 (2000), S. 383-389 
    Details
    ISSN: 1433-0458
    Schlagwort(e): Schlüsselwörter Tip-Link-Hypothese ; Lärmschwerhörigkeit ; Schalltrauma ; Tinnitus ; TTS ; Key words Tip link hypothesis ; Noise-induced hearing loss ; Tinnitus ; TTS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract Sound overexposure is known to cause damage to cochlear structures and can induce permanent or temporary hearing loss and tinnitus. Perhaps the most sensitive of these structures to sound overexposure are the tip links. In this paper the elecrophysiological effects of pharmacological destruction of the tip links of outer hair cells was investigated. Outer hair cells treated with elastase (20 U/mL) or BAPTA (5 mM) no longer responded to sinusoidal stimuli. In contrast to common belief, transduction channels opened due to loss of tip links. Such opened channels can allow K+ and Ca2+ to enter the cell from the endolymphatic space and could lead to permanent depolarization. This influx of cations caused by loss of tip links, together with the subsequent hair-cell depolarization, might be a source of sensorineural hearing loss and tinnitus associated with acoustic trauma.
    Notizen: Zusammenfassung Eine extreme Lärmexposition ist bekannt dafür, Schädigungen des Gehörs hervorzurufen, die sich in permanenter oder temporärer Schwerhörigkeit und Tinnitus manifestieren können. Vor allem die Stereozilien der Haarsinneszellen stellen einen sensiblen Angriffspunkt dar: deren rämliche Ordnung und ihre Verbindungsfilamente (Tip-Links) können zerstört werden. In der vorliegenden Arbeit wurde die Auswirkung einer pharmakologischen Zerstörung der Tip-Links auf das elektrophysiologische Verhalten der Zelle untersucht. Es zeigte sich, dass die behandelten äußeren Haarsinneszellen nicht mehr mechanosensitiv für nasische Stimuli waren, was die Wichtigkeit der Tip-Links bei der Reiztransduktion unterstreicht. Entgegen der allgemeinen Erwartung gingen die mechanoelektrischen Transduktionskanäle aber in einen offenen Zustand über. Durch die permanent offenen Kannäle strömen dauerhaft hauptsächlich K+- und Ca2+-Ionen aus der Endolymphe in die Zelle ein und führen zu einer Depolarisation. Dieser durch den Verlust der Tip-Links verursachte Einstrom von Kationen und die Depolarisation der Zelle können ein Teil der Ursache einer dem Schalltrauma begleitenden Symptomatik wie Innenohrschwerhörigkeit und Tinnitus sein.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001060050585
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