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  • Electronic Resource  (26)
  • Polymer and Materials Science  (23)
  • Key words Phenylketonuria  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 155 (1996), S. S97 
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Intelligence ; Education ; Professional career ; Phenylalanine ; control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The intellectual status and professional careers of 51 young adults with phenylketonuria whose treatment started before 3 months of age are described. Their mean IQ was 97 (SD = 16). Of the IQs, 4% were more than 2 SD below the norm. The distribution of types of schooling of the patients was comparable to that in the German population. The professional careers of nearly all the patients were according to their educational level. Within the sample the outcome was significantly correlated with phenylalanine (Phe) control, even when the patients’ social background was statistically taken into account. The main influence of Phe on intelligence seems to occur during the first decade of life since IQ data remain stable even after Phe levels increased during adolescence.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Genotype ; Treatment ; IQ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The interdependence of the predicted in vitro residual enzyme activity (PRA), as deduced from the complete genotypes of 64 hyperphenylalaninaemic patients, and parameters for diagnosis of hyperphenylalaninaemic disorders, the fluctuation of the phyenlylalanine (Phe) values during treatment, long-term dietary control during treatment, and a parameter for the outcome of therapy (IQ) was investigated by correlation analysis. A highly significant correlation was found between the PRA and diagnostic parameters, as well as the fluctuation of the Phe values during treatment. Significant correlations were also observed between the parameter describing the fluctuation of the Phe values and the IQ, as well as between the quality of dietary control and IQ. The PRA is a valuable tool for the differential diagnosis of hyperphenylalaninaemic disorders and for the prediction of one aspect of the course of the disease which is related to the intellectual outcome of therapy. The quality of dietary control was independent of the genotype, indicating that the outcome of therapy can be successfully manipulated in spite of the genetic make-up.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Phenylalanine ; Magnetic resonance ; imaging ; Evoked potentials ; Myelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract White matter abnormalities on MRI have been observed in phenylketonuria (PKU) patients with late onset neurological symptoms as well as in neurologically inconspicious patients. We investigated 14 early treated adolescents at an age between 12 and 17 years (mean age 14.3 years) with classical PKU as well as one retarded patient with atypical PKU by cranial MRI with spinecho T1-, T2- and proton density sequences. Clinical examination was normal. Visual evoked potential (VEP) examination showed a prolonged latency of peak P100 (mean 122.6 ms; control mean 115.9) and IQ testing showed a mean IQ of 101.1. To investigate the influence of plasma phenylalanine (Phe) levels three approaches were used: Phe was determined for the day of MRI, for a period of 6 months prior to MRI and for lifetime up to 12 years. MRI scans revealed areas of abnormally increased signal intensity on T2-weighted and proton density images in 12 (86%) patients, preferably involving the parieto-occipital lobes. MRI of the patient with atypical PKU was normal. MRI findings correlated most strongly to long-term dietary control up to 12 years. We found no correlation with the other parameters of biochemical control, IQ or VEP latency. The nature and prognosis of MRI abnormalities in neurologically normal PKU patients remain unclear although abnormalities in VEPs which were not associated with the degree of MRI abnormalities in our sample indicate a disturbance in myelination along the visual pathways.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 29 (1998), S. 329-335 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Microstructure and Corrosion Behaviour of a Nitrogen Alloyed Stainless SteelThe corrosion behaviour of a nitrogen alloyed stainless steel is investigated using potentiodynamic anodic polarization in physiological NaCl solution. The microstructure of forged samples is determined by microscopy and hardness measurements. The steel shows a globular austenitic structure. In the zone of large forging deformation the grains are elongated. Precipitates are observed in which chromium and molybdenium are enriched. The breakdown potentials range from 200 to 1170 mV vs. SCE, most of the values exceed 500 mV. The breakdown potentials decrease with increasing aspect ratio of the grains and increasing hardness. The precipitates are initial sites for pitting and crater shaped metal dissolution.
    Notes: Das Korrosionsverhalten eines stickstofflegierten rostfreien Stahles wird durch potentiodynamische anodische Polarisation in physiologischer NaCl-Lösung untersucht. Der Gefügezustand geschmiedeter Proben wird mikroskopisch und durch Härtemessungen ermittelt. Der Stahl weist ein globulares austenitisches Gefüge auf, in der Zone starker Schmiedeverformung sind die Körner gestreckt. Es liegen Ausscheidungen vor, in denen Chrom und Molybdän angereichert sind. Der Stahl zeigt Durchbruchspotentiale zwischen 200 und 1170 mV vs. SCE, die meisten Werte liegen über 500 mV. Die Durchbruchspotentiale fallen mit zunehmendem Streckungsgrad der Körner und zunehmender Härte ab. Die Ausscheidungen sind Initialpunkte für loch- und kraterförmigen Materialabtrag.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 28 (1997), S. 88-97 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Modification of Titanium by Ion Implantation-A ReviewThis paper reviews investigations concerning the effect of ion implantation on the properties of titanium alloys. The correlations between the process parameters and the phase formation in implanted layers, the wear and strength properties as well as the corrosion and oxidation behaviour are described. The application for joint prostheses is mentioned.
    Notes: Es wird ein Überblick über den Einfluß der Ionenimplantation auf die Eigenschaften von Titanlegierungen gegeben. Die Beziehungen zwischen den Prozeßparametern und der Phasenbildung in ionenimplantierten Schichten, den Verschleiß- und Festigkeitseigenschaften sowie dem Korrosions- und Oxidationsverhalten werden dargestellt. Die Anwendung für Gelenkprothesen wird kurz besprochen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 29 (1998), S. 23-29 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: New Sol-Gel Based Coatings as Corrosion- and Wear-Protection On Non-Ferrous MetalsA new composite coating material has been developed for the protection of non-ferrous alloys (e.g. aluminum, magnesium, zinc and brass). The coating materials were prepared by the solgel process from epoxyalkoxysilanes and aromatic diols to act as crosslinking agents. As solvent, alcohols and glycol ethers have been used.The viscosity of the system (7-55 mPas) was established in a way to be used in spray, dip or flow coating processes. The transparent coatings were cured at T = 100-220°C. In corrosion tests, 3000 hours salt-spray climate and 240 hours CASS-test = Copper chloride and Acetic acid added Salt Spray, no infiltration of the metal-coating interface and no „filiform-corrosion“ on A199.5, AlMg3 and AlMgSil was observed. Brass samples showed less than 4 mm extension of a scribe after 500 hours salt-spray-test. The coatings showed no visible traces of abrasion after 1000 cycles taber abrader test and an excellent adhesion (cross cut and tape-test: grade 0). The transparent basic systems were pigmented by 5 - 10 wt.% of colored organic pigments to obtain all kind of colored coatings.
    Notes: Es wurde ein neuer Beschichtungswerkstoff auf Basis von anorganisch-organischen Kompositen zum Schutz von Metalloberflächen, besonders von Aluminium entwickelt. Das Beschichtungsmaterial wurde über den Sol-Gel-Prozeß synthetisiert, ausgehend von Epoxy-funktionalisierten Alkoxysilanen und aromatischen Diolen als Quervernetzer. Als Lösungsmittel wurden Alkohole und Glykolether verwendet.Die Viskosität der Systeme wurde so eingestellt, daß sowohl Sprüh-, als auch Tauch- und Flut-Beschichtungen durchgeführt werden konnten. Sie lag zwischen 7 und 55 mPas. Nach dem thermischen Verdichtungsprozeß bei 100-220°C wurden transparente Beschichtungen mit ausgezeichneter Haftung auf Al-Mg-, Zn-und Messing-Oberflächen (Gitterschnitt- und Tape-Test: Klasse 0) erhalten. Die Korrosionsfestigkeit beschichteter Aluminiumlegierungen (Al 99.5, AlMg3, AlMgSi I) wurde mit dem Salzsprühverfahren (DIN 50021) und dem CASS-Test (NaCl, CuCl2·2H2O, Essigsäure, pH=3) geprüft und auch nach 3000 Stunden trat keine Unterwanderung der Grenzfläche Metall / Schicht auf. Ebenso wurde keine „Filiform“-Korrosion beobachtet. Messingproben zeigten nach 500 h Salzsprühnebel-Test weniger als 4 mm mittlere Unterwanderungsbreite. Darüber hinaus wurde die Abriebbeständigkeit der Proben überprüft. Die Schichten zeigten keine sichtbare Beschädigung nach Prüfung des Abriebes mit dem Reibradverfahren (1000 Zyklen, Räder: CS 10-F).Es konnten stabile Dispersionen von organischen Farbpigmenten im transparenten Basissystem hergestellt werden, wodurch eine große Vielfalt farbiger Beschichtungen erhalten wurde.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 1 (1990), S. 143-150 
    ISSN: 1042-7147
    Keywords: Reinforcement ; Amorphous ; Matrix ; LC-polyester ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The preparation and the mechanical properties of binary blends of amorphous thermoplastics and a para-linked liquid crystalline polyester, which is expected to act as a reinforcement, are reported. The LC-polyester has the advantage that it is soluble in common organic solvents, that it has a low transition temperature, and that it does not crystallize readily. Polycarbonate, polystyrene, poly(methyl methacrylate), and poly(ether sulfone) were selected as matrix materials. Most of the films cast from the blends turned out to be turbid and thus phase separated, the sizes of the dispersed phases ranging between 0.2 μm (in polycarbonate) and 1 μm (in polystyrene).The LC-polyester causes a substantial increase of the stiffness in blends with polycarbonate, poly(methyl methacrylate), and poly(ether sulfone) and almost no increase in the case of polystyrene. These differences are attributed to the particular magnitudes of the strength of the phase coupling between the matrix and the dispersed phase, which is controlled by their compatibility.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 87-92 
    ISSN: 1057-9257
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The machining of several materials such as polymers, metals and ceramics using excimer lasers (193, 248 and 308 nm) was investigated. By photoablation, micrometer resolution can be achieved for polymers if the wavelength and fluence are chosen properly. High-definition processing of metals is complicated by the occurrence of surface melting. An interaction between the ablation plume and the walls of the laser-drilled holes leads to hole widening in the case of polymers at high fluences. For small structures (〈100 μm) all materials investigated show a size-dependent ablation rate. This effect has to be taken into account if a precise ablation depth is required for a pattern with structures of different sizes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 7 (1997), S. 123-133 
    ISSN: 1057-9257
    Keywords: nanocomposites ; sol-gel ; heteropolymetallates ; photochromics ; holographic data storage ; amplitude grating ; two-wave-mixing recording ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: This paper describes the properties of some new organic-inorganic photochromic layers. They are based on a hybrid organic-inorganic matrix in which tungsten heteropolyoxometallates (SiW12O4-40, PW12O3-40) are entrapped in a network obtained from the reaction of 3-glycidoxy-propyltrimethoxysilane. The high homogeneity of these materials on the nanoscale leads to transparent monoliths and layers of controlled thicknesses up to 40 μm. The optical properties of the blend are emphasised and the construction of amplitude gratings in the materials by two-wave-mixing experiments is described. The results of the optical experiments and the comparison with the theoretical background are used as a model for photochromic holographic storage processes. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 40 (1989), S. 642-650 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Influence of HCl and N2 on high temperature corrosion in atmospheres with low oxygen pressuresThe effects of HCl and N2 on the high temperature corrosion in atmospheres with low oxygen pressures were investigated.Investigations of the alloy Fe-20Cr in He-H2-H2-O-HCl atmospheres at 1173 K under conditions, where no condensed chlorides could be formed, show the simultaneous growth of Cr2O3 and evaporation of CrCl2. The kinetics of the reactions can be described by growth of Cr2O3 according to the parabolic rate law and transport of CrCl2 in the gas flow following a linear rate law.During heating of the samples in He-H2-H2O-HCl condensed chlorides are formed which decrease the adherence of the oxide layers and cause oxide spallation during cooling. This can be avoided either by preoxidation in H2-H2O or heating in dry hydrogen. The porosity of Cr2O3 layers is not enhanced when HCl is added to the gas atmosphere.The oxidation and evaporation is enhanced in N2-H2-H2O-HCl atmospheres compared to He-H2-H2O-HCl atmospheres. The Cr2O3 scales are coarse grained and poros. The enhanced porosity is caused by the nucleation and growth of chromium nitrides in the transient state of oxidation.
    Notes: Der Einfluß von gasförmigem HCl und Stickstoff auf die Hochtemperatur-Korrosion in Atmosphären mit niedrigem Sauerstoffpartialdruck wurde untersucht.Untersuchungen mit der Legierung Fe-20Cr in He-H2-H2O-HCl-Atmosphären bei 1173 K unter Bedingungen, bei denen keine kondensierten Chloride gebildet werden, zeigten, daß gleichzeitig Wachstum von Cr2O3 und Abdampfen von CrCl2 erfolgt. Die Kinetik der Gesamtreaktion läßt sich durch Überlagerung eines parabolischen Zeitgesetzes für das Oxidwachstum mit einem linearen Zeitgesetz für die Abdiffusion des Chlorides in den Gasstrom beschreiben.Beim Aufheizen der Proben in He-H2-H2O-HCl bilden sich kondensierte Chloride, die die Haftung der Oxidschichten beeinträchtigen und Abplatzen beim Abkühlen verursachen. Voroxidation in H2-H2O oder Aufheizen in getrocknetem Wasserstoff verhindern dies. Die Porosität von Cr2O3-Schichten wird durch den Zusatz von HCl zur Gasatmosphäre nicht erhöht.In N2-H2-H2O-HCl-Atmosphären ist die Oxidation und das Abdampfen beschleunigt gegenüber He-H2-H2O-HCl-Atmosphären. Die gebildeten Cr2O3-Schichten sind grobkörnig und porös. Ursache der erhöhten Porosität ist die Keimbildung und das Wachstum von Chromnitriden im Anfangsstadium der Oxidation.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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