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  • 1
    Electronic Resource
    Electronic Resource
    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
    Source: AIP Digital Archive
    Topics: Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1326858
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  • 2
    Electronic Resource
    Electronic Resource
    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
    Source: AIP Digital Archive
    Topics: Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125739
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  • 3
    Electronic Resource
    Electronic Resource
    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
    Source: AIP Digital Archive
    Topics: Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126617
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  • 4
    Electronic Resource
    Electronic Resource
    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
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2000.tb02093.x
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  • 5
    Electronic Resource
    Electronic Resource
    Aggressive periodontitis – what exactly is it? (2004)
    Oxford, UK : Munksgaard International Publishers
    Journal of clinical periodontology 31 (2004), S. 0 
    Details
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-051X.2004.00602.x
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  • 6
    Electronic Resource
    Electronic Resource
    A sub-atomic microscope, superfocusing in channeling and close encounter atomic and nuclear reactions (2004)
    Springer
    The European physical journal 42 (2004), S. 361-365 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A highly collimated beam of protons ( $\approx$ 1 MeV) entering the channel of a monocrystal film forms at a certain depth an extremely sharp (〈0.005 nm) and relatively long (some monolayers of the crystal) focusing area where the increase of the flux density can reach thousand times. Impinging atoms in this focusing area can undergo nuclear or atomic reactions with proper foreign dopants which disappear if the crystal is tilted from this position by only 10-3 radians. This effect can be called channeling superfocusing, in contrast to the ordinary fluxpeaking where the increase of flux density reaches only few times. Results are predicted by quantum mechanical model calculations and confirmed by channeling Monte Carlo simulations accounting for several properties of the real lattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2004-00391-6
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  • 7
    Electronic Resource
    Electronic Resource
    Micromachined, Polyimide-Based Devices for Flexible Neural Interfaces (2000)
    Springer
    Biomedical microdevices 2 (2000), S. 283-294 
    Details
    ISSN: 1572-8781
    Keywords: neural prostheses ; MEMS ; polyimide ; electrical stimulation ; implant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009955222114
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  • 8
    Electronic Resource
    Electronic Resource
    Evidence for deformation in 113-116Cd isotopes (2000)
    Springer
    The European physical journal 7 (2000), S. 347-353 
    Details
    ISSN: 1434-601X
    Keywords: 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
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00013614
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  • 9
    Electronic Resource
    Electronic Resource
    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
    Keywords: Schlüsselwörter Tip-Link-Hypothese ; Lärmschwerhörigkeit ; Schalltrauma ; Tinnitus ; TTS ; Key words Tip link hypothesis ; Noise-induced hearing loss ; Tinnitus ; TTS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: 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.
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001060050585
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  • 10
    Electronic Resource
    Electronic Resource
    Tools for tissue engineering of mineralized oral structures (2000)
    Springer
    Clinical oral investigations 4 (2000), S. 126-129 
    Details
    ISSN: 1436-3771
    Keywords: Key words Tissue engineering ; Growth factors ; Peptides ; Proteins ; Dental
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This paper presents a short review of three groups of tools which can be or are used for the tissue engineering of mineralized oral structures: growth factor delivery systems (GFDS) and surface bioactivation with covalent bound peptides or with nanomechanically linked proteins. According to the reported personal experience of the authors, GFDS have to face the following challenging issue before being used routinely in dentistry, e.g., as a tool for reparative dentinogenesis or bone healing: adaptation of the GFDS design to the tissue where it will be implanted in order to deliver the right dose of growth factor (GF) at the right time. The bioactivation of surfaces, for example of dental implants, with covalent bound peptides or nanomechanically linked proteins represents a second innovative way to improve dental health in the future. Here we report on the experimental use of cyclic RGD peptides grafted on polymethylmethacrylate to improve osteoblast adhesion. Furthermore, we show the potential advantage of immobilizing and incorporating collagen I on titanium implant surfaces. These techniques or a combination of them will help to create improvements, for example, of dental implants in the near future. They will also help to promote bone and dentin regeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007840050128
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