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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK; Malden, USA : Blackwell Publishing Ltd/Inc.
    Wound repair and regeneration 13 (2005), S. 0 
    ISSN: 1524-475X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The role of proteases in chronic wounds has been the subject of many investigations in recent years. These studies have reported biochemical differences between chronic and acute wound fluids and have shown that elevated levels of proteases, in particular the matrix metalloproteinases are abundant in chronic wounds. While this has led to the hypothesis that the chronic wound environment is hostile and not conducive to wound repair, it is still unknown whether this is due to a direct or indirect defect in protease regulation or their inhibitors.We hypothesize that an excess of proteases, specifically the serine proteases present in chronic wounds, are primarily responsible for this hostile wound environment. These proteases degrade endogenous growth factors, reducing their efficacy and delaying healing.In this study, fluid and tissue from chronic and acute wounds were collected over a 24-hour period. Using ELISA, samples were assessed for protease activity (specifically elastase and typsin-like enzymes), their inhibitors and growth factors.Our results show that serine proteases, predominantly elastase, were significantly elevated in the chronic wound fluids. The serpins designed to control these proteases were not up-regulated when compared to the acute controls, resulting in excessive proteolytic activity. An increase in serine protease production without an increase in their serpins is thought to result in a reduction in growth factors, an effect, which was also observed in the chronic wound samples.This work indicates that there is an imbalance in the ratio of inhibitor to enzyme, due to an up regulation of protease production in chronic wounds. We also conclude that misregulation of serine proteases may be responsible for the observed excessive degradation of the extracellular matrix and growth factors in these chronic wounds.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 2070-2072 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Twenty-element near-resonant AlGaAs/GaAs arrays of antiguides have been optimized for maximum intermodal discrimination and large Strehl ratio. It is found that 1000-μm-long devices with two intracavity Talbot-type spatial filters, and a 3 to 1 ratio between element core and interelement spacing provide the best results. The intermodal discrimination is discussed for both Talbot and uniform devices. For devices with two Talbot-type spatial filters, diffraction-limited-beam operation is obtained to 1 W pulsed power, and operation in a beam with lobewidth 1.5× diffraction limit is obtained to 2 W and 19× threshold. cw diffraction-limited-beam operation is obtained to 0.5 W, limited by thermal considerations. Uniform devices operate in beams with lobewidth ≈3× diffraction limit to 5 W and 45× threshold. At 5 W total output the coherent uniphase power is 1.6 W, and the coherent power in the main lobe is 0.94 W.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 22-24 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Monolithic phase-locked resonant arrays of antiguides, resonant optical-waveguide (ROW) arrays, have been optimized for efficient in-phase-mode operation. Diffraction-limited, in-phase-mode continuous-wave (cw) operation is obtained from 20-element uniform arrays to 250 mW output power, with (front facet) external differential quantum efficiencies of 41%. Single longitudinal mode operation is observed below 100 mW cw. In-phase-operating devices with and without Talbot-type spatial filters are compared, and it is found that for ROW arrays Talbot-type spatial filters are not required.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2060-2062 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Pure in-phase-mode operation is obtained from 20/21-element AlGaAs/GaAs antiguided arrays grown by two-step metalorganic chemical vapor deposition. Oscillation of out-of-phase modes is substantially suppressed by a built-in spatial filter: two sets of noncollinear antiguides separated by a 50-μm-long laterally unguided region, corresponding to the half-Talbot distance. Design considerations for 20- vs 10-element arrays are discussed. Diffraction-limited-beam operation (i.e., 0.8° lobewidth) is obtained to 1.5×threshold (90 mW, both facets). Beams with 1.3° lobewidth (1.6×diffraction limit) are obtained at 3×threshold and 300 mW (both facets). Devices with optimized facet coatings operate in a single, 1.5°-wide lobe (i.e., 1.8×diffraction limit) at 330 mW front-facet emitted power. The main lobe contains 80–87% of the total power.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 2183-2185 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Uniform linear arrays of antiguides have 100% optical transmission between elements when the interelement spacing is an integer number of leaky wave half-wavelengths in the lateral direction. Resonant in-phase-mode and out-of-phase-mode coupling occurs when the number of half-wavelengths is odd and even, respectively. Such devices are called resonant optical waveguide (ROW) arrays. The discrimination between the resonant array mode and adjacent array modes reaches a maximum in close proximity to the resonance. An AlGaAs/GaAs ROW diode laser array operating close to resonance is demonstrated. Devices with virtually uniform near-field intensity profiles operate in stable, diffraction-limited in-phase modes to drive levels in excess of three times threshold.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 464-466 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A novel type of phase-locked diode-laser array is demonstrated: an array of closely spaced index depressions (antiguides). The arrays are ten-element AlGaAs/GaAs devices fabricated by metalorganic chemical vapor deposition and liquid phase epitaxy over a patterned substrate. The fundamental and highest-order modes of the array of antiguides have negligible radiation loss: 20–30 times less than that for a single antiguide. The modal-gain differentials between adjacent array modes are at least an order of magnitude larger than those for evanescently coupled arrays of positive-index guides. Fundamental-array-mode operation in a virtually diffraction-limited-beam (1.4°) pattern is obtained to 200 mW. Out-of-phase-mode operation in a virtually diffraction-limited-beam (1.2°) pattern is achieved to 110 mW/uncoated facet. The inherent array-mode stability of antiguided arrays is discussed.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 1236-1238 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A novel index-guided, wide-waveguide coupled array structure grown entirely by metalorganic chemical vapor deposition has been demonstrated, which operates in a stable high-order array mode, remaining nearly diffraction limited to high drive currents (〉5Ith ) and high-power levels (145 mW/uncoated facet). Strong lateral mode confinement (Δneff ≈1×10−2 ) at the element level coupled with the wide-waveguide geometry ensures operation in coupled first-order element modes. The out-of-phase operating array structure has interelement coupling that becomes stronger with increasing drive level, thereby offering stability against gain spatial hole burning at both the array level and the individual element level.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 266-268 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Single-array-mode (L=8) oscillation is achieved with virtually diffraction-limited beams to three times above lasing threshold, and with beamwidths 1.5 times the diffraction limit at 4.7 times above lasing threshold and 130 mW output power per uncoated emitting facet. The arrays are 10/11-element wide-waveguide-interferometric (WWI) AlGaAs/GaAs lasers grown by liquid-phase epitaxy over channeled substrates. Selection of the L=8 mode is a consequence of two mode-dependent loss mechanisms: transverse antiguiding between elements and radiation losses in the interferometer. Near-field pattern analysis indicates that the (high-order) array mode is self-stabilizing with increasing drive above threshold. Simple means of achieving single-lobe operation are discussed.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1959-1961 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Vertical-cavity surface emitters with rear mirrors made of conductive semiconductor stack reflectors (Rr =98%) were developed. Current confinement is obtained via an etch and regrowth technique with no need for dielectrics. Peak powers of 120 mW were achieved at room temperature. The external differential quantum efficiency is 15%.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 1366-1368 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A novel type of phase-locked array is demonstrated. The device is a ten-element AlGaAs/GaAs array with both evanescent wave coupling as well as coupling via X-type junctions. The array selects and maintains operation in the highest order array mode of a ten-element device: mode L=10. Threshold currents are ∼300 mA. Diffraction-limited-beam operation is achieved to 2.8×threshold and ∼200 mW (front facet of devices with optimized facet coatings). The beam lobewidths remain under 1.5×diffraction limit to 6.3×threshold and 300 mW (both facets of uncoated devices). Near-field intensity patterns confirm the intrinsic stability of high-order array modes against gain spatial hole burning.
    Materialart: Digitale Medien
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