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  • 1
    Electronic Resource
    Electronic Resource
    Size quantization effects in InAs self-assembled quantum dots (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1727-1729 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We study size quantization effects in InAs self-assembled quantum dots (QDs) that are embedded in GaAs. Using capacitance, photoluminescence and photovoltage spectroscopy, we correlate the measured quantized level energies with the quantum dot sizes and densities obtained from transmission electron microscopy. With increasing dot size, we observe a strong redshift of the QD features in all our data. In the capacitance spectra, a band gap renormalization of the two-dimensional wetting layer system appears when the first excited QD state crosses the wetting layer ground state. The relative size dependence and absolute energetic position of the QD transitions determined with photoluminescence provide some information about the influence of lateral confinement and height of the QD. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118682
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of the activation energy for the heterogeneous nucleation of misfit dislocations in Si1−xGex/Si deposited by selective epitaxy (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 324-326 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Si0.84Ge0.16/Si heterostructures with variable finite lateral dimensions (10–300 μm) and different layer thicknesses grown by selective low pressure chemical vapor deposition epitaxy at a temperature of 700 °C were investigated with regard to relaxation by formation of misfit dislocations. While in small structures only nucleation and propagation occur, the dislocation–dislocation interaction (mainly multiplication) becomes more and more important in larger structures. Therefore it was possible to separate the three different mechanisms which play a role in relaxation, i.e., nucleation, propagation, and multiplication, and to study them independently. From the analysis of the misfit dislocations at the initial stage of relaxation it was possible to determine the nucleation site density and an activation energy of 2.8 eV for the heterogeneous nucleation of misfit dislocations. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118404
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  • 3
    Electronic Resource
    Electronic Resource
    Size distribution of Ge islands grown on Si(001) (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 410-412 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Atomic force microscopy analyses were performed on Ge islands on Si(001) grown by low pressure chemical vapor deposition in the temperature range from 525 to 700 °C. A comparison with theoretical models describing the growth of coherently strained and plastically relaxed islands is given to describe the observations. The mean diameter of coherently strained islands is found to be 170 nm over a wide range of temperature, whereas plastically relaxed islands grow up to diameters 〉500 nm. The aspect ratio turns out to be independent of the presence of dislocations. For the sample grown at 700 °C three size regimes could be observed, whereas the sample grown at the lowest temperature exhibits no island formation. At 550 °C islands with an average diameter of 33 nm and a low aspect ratio were observed; these could prove to be interesting in applications using quantum confinement effects. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.119553
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  • 4
    Electronic Resource
    Electronic Resource
    Intermixing and shape changes during the formation of InAs self-assembled quantum dots (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 2014-2016 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The initial stages of GaAs overgrowth over self-assembled coherently strained InAs quantum dots (QDs) are studied. For small GaAs coverages (below 5 nm), atomic force microscopy (AFM) images show partially covered island structures with a regular size distribution which are elongated in the [011] direction. Analysis of the AFM profiles show that a large anisotropic redistribution of the island material is taking place during the initial GaAs overgrowth. Short time annealing experiments together with photoluminescence spectroscopy on annealed QDs are consistent with a Ga and In intermixing during the overgrowth. Surface QDs capped with 5 nm or more GaAs show a strong luminescence intensity indicating that surface QDs are remarkably insensitive to surface recombination effects. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.119772
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  • 5
    Electronic Resource
    Electronic Resource
    Exopolysaccharide production from whey lactose by fermentation with Lactobacillus delbrueckii ssp. bulgaricus (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 62 (1997), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ropy Lactobacillus delbrueckii ssp. bulgaricus (strain RR) was used for production of exopolysaccharide in sweet whey and simulated whey permeate (SWP) supplemented with combinations of lactose, KH2PO4, NH4Cl, casamino acids, and mineral salts. Media were incubated at 32, 37, and 44°C for 72h. Periodic adjustment of pH to ∼6.2 increased viscosity and lactose utilization, and the free galactose and lactic acid in the media. The effect of pH adjustment was greater than that of supplementation with nutrients or minerals. Fermentation of supplemented SWP generally produced lower viscosities than did fermentation of supplemented sweet whey. After 24h fermentation, viscosity decreased in pH adjusted media. Viscosity of media was highest when incubation was at 32°C and lowest with incubation at 44°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1997.tb04393.x
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  • 6
    Electronic Resource
    Electronic Resource
    Release of nitric oxide from donors with known half-life: a mathematical model for calculating nitric oxide concentrations in aerobic solutions (1997)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 355 (1997), S. 457-462 
    Details
    ISSN: 1432-1912
    Keywords: Key words Nitric oxide donor ; Release of nitric oxide ; Concentration-time profile ; Mathematical modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The NO concentrations released from donor compounds are difficult to predict as they are determined by formation and inactivation reactions. To calculate the concentrations of NO over time, we have developed a mathematical model which is based on a system of two differential equations describing the first order decomposition of the NO donor in association with the third order reaction of NO with oxygen. Although there is no closed formula for the solution, it can be easily computed by any standard numerical differential solver or simulation software with the following input parameters: initial concentration and decomposition rate constant of the NO donor, O2 concentration, and rate constant for NO autoxidation. The model was validated by monitoring NO release from 2,2-diethyl-1-nitroso-oxyhydrazine (DEA/NO) with a Clark-type NO-sensitive electrode at two different temperatures (25 and 37°C) and DEA/NO concentrations ranging from 1 to 10μM. Under all conditions, there was an excellent agreement between experimental and calculated data. In addition to the computer modeling, we present graphical plots which allow a rough but very easy estimation of the actual NO concentrations if appropriate computer software should not be available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00004969
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  • 7
    Electronic Resource
    Electronic Resource
    Okuläre Pulsamplitude und lokale Karboanhydrasehemmung (1997)
    Springer
    Der Ophthalmologe 94 (1997), S. 659-664 
    Details
    ISSN: 1433-0423
    Keywords: Schlüsselwörter Primäre Offenwinkelglaukome ; Aderhaut ; Okuläre Pulsamplitude ; Choroidale Perfusion ; Vasospasmus ; Key words Primary open-angle glaucomas ; Choroid ; Ocular pulse amplitude ; Choroidal perfusion ; Topical carbonic anhydrase inhibitor ; Dorzolamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Ocular perfusion is increasingly being discussed in the pathogenesis of glaucoma. The present study was designed to investigate ocular pulse amplitude (OPA) in primary open-angle glaucoma (POAG) patients with elevated intraocular pressure (HTG) and nonglaucomatous controls (CTL) following topical application of the carbonic anhydrase inhibitor dorzolamide. Methods: OPA (Ocular Blood Flow System, OBF Labs UK) intraocular pressure (IOP), heart rate (HR), and systolic (BPsyst) and diastolic (BPdiast) bronchial artery pressures were measured before and 2 days after initiating treatment in 33 cataract patients with (n = 14) and without (n = 19) POAG. Results: Following application of dorzolamide, IOP (mmHg) in drug-treated HTG and CTL eyes was highly significantly reduced (p〈0.001) and in vehicle-treated HTG and CTL eyes significantly reduced (p〈0.03) compared to respective baseline measurements. OPA (mmHg) in drug-treated HTG and CTL eyes was significantly increased (p〈0.05) and in vehicle-treated eyes in affected compared to respective baseline measurements. Systemic perfusion parameters were also unchanged. Conclusion: Dorzolamide increased OPA in HTG and CTL eyes. An increase in OPA may improve the prognosis of HTG.
    Notes: Hintergrund: Die Bedeutung der okulären Perfusion in der Pathogenese der Glaukome wird zunehmend diskutiert. Ziel der vorliegenden Studie war es, die okuläre Pulsamplitude (OPA) bei Patienten mit primärem Offenwinkelglaukom mit erhöhtem IOD (HDG) und einer Kontrollgruppe ohne Glaukom (KTL) nach Gabe des lokalen Karboanhydrasehemmers Dorzolamid zu untersuchen. Methode: Die OPA, der intraokulare Druck (IOD), systolischer und diastolischer Blutdruck und die Herzfrequenz wurden bei 33 Kataraktpatienten mit (n = 14) und ohne (n = 19) HDG vor und 2 Tage nach Therapiebeginn bestimmt. Ergebnisse: Nach Gabe von Dorzolamid sank der IOD in den behandelten Augen der Patienten mit HDG und KTL hochsignifikant und in den Kontrollaugen signifikant ab, die OPA war nur in den behandelten Augen der Patienten mit HDG und KTL signifikant erhöht. Die systemischen Perfusionsparameter waren unbeeinflußt. Schlußfolgerung: Dorzolamid führt zu einem Anstieg der OPA bei Patienten mit HDG und KTL. Eine Steigerung der OPA könnte die Prognose beim HDG verbessern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003470050179
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  • 8
    Electronic Resource
    Electronic Resource
    Proprioceptive abilities of patients with a patellar pain syndrome with special reference to the effect of an elastic knee bandage (1997)
    Springer
    Der Unfallchirurg 100 (1997), S. 719-723 
    Details
    ISSN: 1433-044X
    Keywords: Key words Proprioception • Patellar pain syndrome ; Schlüsselwörter Propriozeptive Fähigkeiten • Retropatellares Schmerzsyndrom
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mit Hilfe eines passiven Winkelreproduktionstests wurden an 43 Kniegelenken mit retropatellarem Knieschmerz propriozeptive Fähigkeiten dokumentiert und mit einem Kollektiv von 30 Probanden verglichen, die anamnestisch und klinisch unauffällige Kniegelenke aufwiesen. Zusätzlich wurden die Messungen mit einer elastischen Kniebandage durchgeführt, um ihre Wirkung auf die Winkelreproduktionsfähigkeit zu überprüfen. Die Patienten mit retropatellaren Schmerzen wiesen eine durchschnittliche Abweichung vom vorgegebenen Winkel von 13,2 °± 6,1 ° auf. Diese Ergebnisse waren signifikant schlechter als die der gesunden Kontrollgruppe (7,8 °± 2,8 °). Durch die Benutzung einer Kniebandage verbesserten sich die Winkelabweichungen der Patientengruppe signifikant auf 9,2 °± 4,5 °. Die Ergebnisse der klinisch gesunden kontralateralen Kniegelenke der Patientengruppe zeigten mit 11,6 °± 6,3 ° ebenfalls schlechtere Winkelreproduktionswerte im Vergleich zur Kontrollgruppe. Durch die Kniebandage konnte keine signifikante Beeinflussung der gesunden Kniegelenke der Patientengruppe (10,1 °± 5,3 °) erreicht werden.
    Notes: Summary In the presented study, knee joint proprioception of 43 patients with a patellar pain syndrome of the knee joint was evaluated. In a control group, the proprioception of 30 healthy volunteers with clinical and anamnestic inconspicous knee joints was examined. We tested the proprioceptive capability of the subjects with a passive angle reproduction test. Additionally, all knee joints were measured with and without an elastic knee bandage. The patient group showed significant deterioration of angle reproduction capability (13.2 °± 6.1 °) compared to the control group (7.8 °± 2.8 °). After applying an elastic knee bandage, the angle reproduction capability significantly improved to 9.2 °± 4.5 °. Proprioception of the contralateral, noninvolved knee joint in the patients (11.6 °± 6.3 °) was worse compared to the control group. Applying an elastic knee bandage did not significantly improve the proprioception of the uninjured knee joint.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050183
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  • 9
    Electronic Resource
    Electronic Resource
    Beeinflussung der propriozeptiven Fähigkeit von Kniegelenken mit einer primären Gonarthrose (1997)
    Springer
    Der Unfallchirurg 100 (1997), S. 219-224 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter Propriozeption ; Gonarthrose ; Key words Proprioception ; Gonarthrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: In the study presented, knee joint proprioception of 17 patients with primary degenerative joint disease of the knee joint was evaluated. As a control group, the proprioception of 30 healthy volunteers with clinical and anamnestically inconspicuous knee joints was examined. We tested the proprioceptive capability of the subjects with an angle reproduction test. Additionally, all knee joints were measured with and without an elastic knee bandage. The study showed significantly more deterioration in knee joint proprioception in patients with gonarthrosis than in the control group. Even the proprioception of the contralateral, healthy knee joint was worse than the results of the control group. However, after using an elastic knee bandage, significant improvement in the proprioceptive abilities of the injured knee joint was documented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050114
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  • 10
    Electronic Resource
    Electronic Resource
    Extensions of cocycles for hyperfinite actions and applications (1997)
    Springer
    Monatshefte für Mathematik 123 (1997), S. 209-228 
    Details
    ISSN: 1436-5081
    Keywords: 28D05 ; 28D15 ; 28D99 ; Cocycles ; ergodic equivalence relations ; factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Given a countable, hyperfinite, ergodic and measure-preserving equivalence relationR on a standard probability space (X, ℬ, μ) and an elementW of the normalizerN (R) ofR, we investigate the problem of extendingR-cocycles to $$\bar R$$ , where $$\bar R$$ is the relation generated byR andW. As an application, we obtain that for a Bernoulli automorphism the smallest family of natural factors in sense of [6] consists of all factors. Given an automorphism which is embeddable in a measurable flow and a compact, metric group, we show that for a typical cocycle we cannot lift the whole flow to the centralizer of the corresponding group extension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318233
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