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  • 1
    Electronic Resource
    Electronic Resource
    Direct imaging of the spectral emission characteristic of an InGaN/GaN-ultraviolet light-emitting diode by highly spectrally and spatially resolved electroluminescence and photoluminescence microscopy (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3440-3442 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The microscopic spectral emission characteristic of an InGaN/GaN double-heterostructure light-emitting diode is directly imaged by highly spectrally and spatially resolved scanning electroluminescence microscopy under operation as a function of injection current density. The luminescence intensity maps and especially the peak-wavelength scanning images provide access to the optical quality of the final device and yield direct images of the In fluctuations with 1 μm spatial resolution. Indium concentrations varying from 6% to 9% are found in the active InGaN region of the ultraviolet diode emitting at 400 nm. While for low injection current densities the electroluminescence is dominated by emission from the p GaN originating from the whole accessible area, the emission from the InGaN active layer increases and takes over for higher injection conditions showing a strongly localized spatial emission characteristic. Correlation of the results with low-temperature scanning photoluminescence microscopy enables the identification of the underlying recombination processes. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125289
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  • 2
    Electronic Resource
    Electronic Resource
    Ultraviolet Stabilizers of the 2-(2'-Hydroxyphenyl)-1,3,5-triazine Class: Structural and Spectroscopic Characterization (1995)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 10097-10109 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100025a009
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  • 3
    Electronic Resource
    Electronic Resource
    Turning the key on p53 (2004)
    [s.l.] : Nature Publishing Group
    Nature 427 (2004), S. 789-790 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Almost exactly 25 years ago, a report appeared describing the interaction between a cancer-causing virus and a host protein dubbed 53K. That entity, since called p53 and recognized as a tumour-suppressor protein because of its ability to prevent undue cell proliferation, has attracted ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/427789a
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  • 4
    Electronic Resource
    Electronic Resource
    Evaluation of the interface between bone and titanium surfaces being blasted by aluminium oxide or bioceramic particles (2003)
    Oxford, UK : Munksgaard International Publishers
    Clinical oral implants research 14 (2003), S. 0 
    Details
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The surface structure, in particular the surface roughness, and the surface chemistry of titanium implants influence their anchoring in bone. The aim of this study was to analyse metal–bone contact (MBC) after modification of the implant surface, using different materials for blasting. The surface modification of titanium was produced by blasting it with particles made of Al2O3 or bioceramics. The biological effects were then investigated experimentally using 27 rabbits, analysed after 7, 28 and 84 days after the implantation of titanium cylinders treated accordingly. The MBC showed a tendency for more bone after bioceramics were used as a blasting material, compared to Al2O3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0501.2003.00791.x
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  • 5
    Electronic Resource
    Electronic Resource
    Non-linear flow properties of viscoelastic surfactant solutions (1997)
    Springer
    Rheologica acta 36 (1997), S. 13-27 
    Details
    ISSN: 1435-1528
    Keywords: Viscoelastic surfactant solution ; non-linear flow ; Giesekus model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract This paper gives a quantitative description of the viscoelastic properties of aqueous solutions of entangled rod-shaped micelles. The experimental data are compared with the theoretical predictions of a special constitutive equation which is based on the concept of deformation-dependent tensorial mobility. In the regime of small deformations, shear stresses or shear rates, the dynamic features of the viscoelastic solutions are characterized by the equations of a simple Maxwell material. These phenomena are linked to the average lifetime of the micellar aggregates and the rheological properties are controlled by kinetic processes. At these conditions one observes simple scaling laws and linear relations between all theological quantities. At elevated values of shear stresses or deformations, however, this simple model fails and non-linear properties as normal stresses, stress overshoots or shear-thinning properties occur. All these phenomena can be described by a constitutive equation which was first proposed by H. Giesekus. The experimental results are in fairly good agreement with the theoretical predictions, and this model holds for a certain, well defined value of the mobility factor α. This parameter describes the anisotropic character of the particle motion. In transient and steady-state flow experiments we always observed α = 0.5. Especially at these conditions, the empirically observed Cox-Merz rule, the Yamamoto relation and both Gleißle mirror relations are automatically derived from the Giesekus model. The phenomena discussed in this paper are of general importance, and can be equally observed in different materials, such as polymers or proteins. The viscoelastic surfactant solutions can, therefore, be used as simple model systems for studies of fundamental principles of flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366720
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  • 6
    Electronic Resource
    Electronic Resource
    Limbal relaxing incisions (LRI) for correcting astigmatism in clear corneal cataract surgery (1999)
    Springer
    Der Ophthalmologe 96 (1999), S. 432-436 
    Details
    ISSN: 1433-0423
    Keywords: Key words Reduction of astigmatism • Clear corneal cataract surgery • Limbal relaxing incision ; Schlüsselwörter Astigmatismusreduktion • Korneale Kataraktchirugie • Limbale Entlastungsschnitte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Fragestellung: Vermeidung einer Astigmatismusinduktion nach nahtfreier kornealer Kataraktchirugie. Patienten und Methoden: Bei 52 Patienten mit sphärischer Hornhaut bzw. Astigmatismus mit der Regel von 0,8 ± 0,3 dpt wurden oben und unten limbale relaxierende Inzisionen (LRI) von 6 bzw. 8 mm Länge und 0,5 mm Tiefe nach temporalem kornealen Starschnitt durchgeführt. Als Kontrolle diente die gleiche Anzahl von Patienten, die mit gleicher Katarakttechnik, jedoch ohne Keratotomien operiert wurden. Ergebnisse: Die refraktive Veränderung in der LRI-Achse bei Anwendung der Berechnungsformel von Holladay (WTW = with-the-wound-change) betrug bei den limbal keratotomierten Patienten mit präoperativ sphärischer Hornhaut nach 6 Monaten –0,08 ± 0,5 dpt, bei der Kontrollgruppe + 0,5 ± 0,7 dpt. Bei den Patienten, die einen präoperativen Astigmatismus mit der Regel aufwiesen, lag die refraktive Veränderung in der LRI-Schnittachse (WTW) 6 Monate postoperativ bei –0,09 ± 0,5 dpt, in der Kontrollgruppe bei + 0,39 ± 0,7 dpt. Schlußfolgerung: Die limbale Keratotomie ist eine zuverlässige und sichere Methode zur Reduktion postoperativer Astigmatismen nach Kataraktchirurgie.
    Notes: Background: To prevent surgically induced astigmatism following clear corneal cataract surgery. Patients and methods: Limbal relaxing incisions of 6 or 8 mm length respectively and 0.5 mm depth were performed in 52 patients with spheric cornea or astigmatism with the rule of 0.8 ± 0.3 dpt after temporal corneal cataract incision. The same amount of patients, operated on with the same surgical procedure except keratotomies, served as control. Results: After 6 months the with-the-wound-change (WTW) in the LRI axis using the Hollady method was –0.08 ± 0.5 dpt in the spheric cases with limbal keratotomy and + 0.5 ± 0.7 dpt in the control cases. The patients with preoperative astigmatism with the rule showed a WTW in the LRI axis of –0.09 ± 0.5 dpt in the keratotomy cases and + 0.39 ± 0.7 dpt in the corresponding control patients. Conclusion: Limbal relaxing incision is a reliable and safe procedure to reduce postoperative astigmatism after cataract surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003470050432
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  • 7
    Electronic Resource
    Electronic Resource
    Fractionated administration of high-dose cyclophosphamide: influence on dose-dependent changes in pharmacokinetics and metabolism (1999)
    Springer
    Cancer chemotherapy and pharmacology 43 (1999), S. 263-268 
    Details
    ISSN: 1432-0843
    Keywords: Key words Cyclophosphamide ; High dose ; Pharmacokinetics ; Application schedule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: The alkylating agent cyclophosphamide (CP) is a prodrug that is metabolized to both cytotoxic and inactive compounds. We have previously shown that following dose escalation from conventional-dose (CD) to high-dose (HD) levels; the fraction of the dose cleared by bioactivation is significantly decreased (66% versus 48.5%) in favor of inactivating elimination pathways when the HD is given as a single 1-h infusion. Based on the concept of bioactivating enzyme saturation with increasing doses, we investigated the influence of fractionated application of HD-CP on dose-dependent changes in metabolism. Patients and methods: Plasma concentrations of CP (measured by high-performance liquid chromatography, HPLC) and urinary concentrations of CP and its major metabolites (quantified by [31P]-nuclear magnetic resonance spectroscopy; [31P]-NMR spectroscopy), were determined in four patients with high-risk primary breast cancer who received adjuvant chemotherapy including both CD-CP (500 mg/m2 infused over 1 h) and split HD-CP (50 mg/kg infused over 1 h on each of 2 consecutive days (d): d1 and d2. Results: (Data are given as mean values for CD and d1/d2 of HD, respectively). Systemic clearance (CL) of CP was similar during CD and d1 of HD, but significantly increased on d2 of HD (CL: 83 and 78/115 ml/min; P 〈 0.01 for d1 versus d2). The latter was translated into an increase in formation CL of both active (+16.4 ml/min) and inactive metabolites (+17.6 ml/min) and reflects autoinduction of metabolism. As compared with CD-CP, no statistically significant decrease was observed in the relative contribution of bioactivation CL to overall CL during both days of HD (63% versus 57%/53%). Recovery of intact CP in 24-h urine corresponded to 24%, 29%, 22% of the dose (P 〈 0.05 for d1 versus d2 of HD). Conclusions: Following dose escalation of CP, dividing the high dose over 2 days instead of one single infusion may favorably impact the metabolism of CP in terms of bioactivation. In addition, on day 2 of a split regimen, renal elimination of CP is decreased, which implies that more drug is available for metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002800050893
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  • 8
    Electronic Resource
    Electronic Resource
    IgG rheumatoid factors isolated by the surface-displaying phage library technique (1997)
    Springer
    Immunogenetics 45 (1997), S. 301-310 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Our analysis of IgG rheumatoid factors (RFs) from three patients with rheumatoid arthritis (RA) revealed that most contained significant numbers of skewed mutations per V region, suggesting that these RFs arose from antigen-driven responses. To further study IgG RFs in RA, we used pComb3 vector to construct an IgG1,λ combinatorial antibody library from a synovial fluid sample. After panning against human IgG, Fab fragments from 71/96 phage clones bound to Fc-coated wells. Sequence analysis of 20 randomly chosen Fc-binders showed that 17 (85%) clones had identical heavy (H) and light (L) chain V regions, represented by Humha311 and Humla211, respectively. Of the remaining three clones, two had the same Humla211 L chain, but each with a different H chain V region. All the putative germline V genes for these RFs also encode RF in RA patients. However, none of these RF V regions are similar to those of the two IgG RFs derived by the hybridoma technique from the same synovial fluid. The Humha311 H chain has two frameshifts: a one-base insertion upstream of the JH region and a four-base deletion near the end of the CH1 region, resulting in a mainly unconventional amino acid sequence in the CH1 region. In the future, it will be important to study the presence of IgG molecules with such unconventional CH1 amino acid sequences, and the effects of these amino acid sequences on the structures and immunological properties of the IgG molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002510050209
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  • 9
    Electronic Resource
    Electronic Resource
    Preparation of optically pure chiral amines by lipase-catalyzed enantioselective hydrolysis of N-acyl-amines (1996)
    Springer
    Biotechnology techniques 10 (1996), S. 335-338 
    Details
    ISSN: 1573-6784
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A new and effective method using lipase from Candida antarctica (native or Novozym SP-435) for the preparation of enantiopure primary R-amines is reported. Hydrolysis of rac-N-acetyl-amines resulted in high conversion 〉 40% (168 hrs) and 〉 48% (〉 240 hrs) and enantiomeric excesses (〉 99% ee) for both the product and the remaining substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173249
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  • 10
    Electronic Resource
    Electronic Resource
    Time dependent flow in equimolar micellar solutions: transient behaviour of the shear stress and first normal stress difference in shear induced structures coupled with flow instabilities (2000)
    Springer
    Rheologica acta 39 (2000), S. 234-240 
    Details
    ISSN: 1435-1528
    Keywords: Key words Viscoelastic surfactant solution ; Shear induced structure ; Flow instabilities ; First normal stress difference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract Recently we studied time dependent structural changes that are coupled with flow instabilities (Fischer 1998; Wheeler 1998; Fischer 2000). Within a stability analysis, a classification scheme for the feedback circuit of coupled shear-induced structure and flow instabilities was derived by Schmitt et al. (1995) and applied to our samples. Here, inhomogeneous flow layers of different concentration and viscosity are generated by shear-induced diffusion (spinodal demixing) and, as consequence, one no longer observes a homogeneous solution but a type of shear banding that is seen here for the first time. In this paper we present the behaviour of the first normal stress difference observed in the critical shear-rate regime where transient shear-induced structure is coupled with flow instability. Similar to the oscillations of the shear stresses (strain-controlled rheometer) one observes oscillations in the first normal stress difference. This behaviour indicates that elastic structures are built up and destroyed while the shear-induced structures occur and that the induced phase is more elastic than the initial one. Oscillations of shear stress and first normal stress difference are in phase and indicate that both phenomena are caused by the same mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003970000087
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