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  • Polymer and Materials Science  (23)
  • Phenylketonuria  (4)
  • sol-gel  (4)
  • 1
    ISSN: 1432-1076
    Keywords: CNS development ; Dietary treatment ; EEG ; IQ ; Phenylketonuria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In 34 children with phenylketonuria (PKU) treated early the prognostic value of the age on institution of the diet (within the first 3 months of life) and of the quality of dietary treatment was determined in two different ways: 1) following intelligence closely (IQ) and (2) evaluating the EEG development up to their 12th (n=34) and 15th (n=18) years of life as appropriate. In general, IQ scores were found to be normal from the 4th–15th years of life. In our group of patients there was no effect on the IQ of the timing of diet onset. Children with “strict” dietary control showed a significantly higher IQ than those with “loose” control. One hundred and fifty-four EEGs (10/20 system, awake with eyes closed) were recorded at intervals of 2 years and conventionally evaluated. The development of alpha-activity was found to be normal. Beta-activity was enhanced. Abnormal EEG findings like general slowing and generalized paroxysmal activity (GPA) with or without spikes were more frequent in children with PKU than in controls, with the exception of focal abnormalities. EEG abnormalities increased with advancing age independently of IQ development and showed no relation to either the age at the onset nor the quality of dietary treatment.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 146 (1987), S. A17 
    ISSN: 1432-1076
    Keywords: Phenylketonuria ; Adolescents ; Dietary control ; Intelligence ; Psychological problems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1076
    Keywords: Phenylketonuria ; Biopterin ; Phosphate-eliminating enzyme ; 6-Pyruvoyl tetrahydropterin synthase ; Amniotic fluid ; Erythrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Amniocentesis was performed at 19 weeks gestation in a mother who had previously delivered a boy with “dihydrobiopterin synthetase” (DHBS) deficiency. The amniotic fluid contained neopterin in high (136 nmol/l) and biopterin in very low concentrations (1.8 nmol/l). The activity of the phosphate-eliminating enzyme (PEE, also called 6-pyruvoyl tetrahydropterin synthase, substrate: 7,8-dihydroneoptein triphosphate) which is present in liver and erythrocytes and defective in DHBS deficiency, was measured in the erythrocytes of the family members. The fetal sample showed only 2% of the activity of healthy adult controls and was comparable with that of the affected sibling. Obligate heterozygotes had activities around 20% of the controls. Two fetal control samples showed even higher activities than adult erythrocytes. Sepiapterin reductase activities were normal in all cases. At autopsy, PEE deficiency was confirmed in the liver of the fetus. We concluded that DHBS deficiency (and most probably also GTP cyclohydrolase I deficiency) can be diagnosed by metabolite measurements in amniotic fluid. PEE activity is measurable in erythrocytes, although the assay needs to be improved. Since maternal tetrahydrobiopterin does not cross the placenta, treatment of a tetrahydrobiopterin-deficient fetus with tetrahydrobiopterin in utero is not possible.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 157 (1998), S. 824-830 
    ISSN: 1432-1076
    Keywords: Key words Intelligence ; Neurology ; Neuropsychology ; Phenylketonuria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Due to the observation of severe neurological symptoms in single patients as well as brain imaging, neuropsychological and neurophysiological abnormalities, the long-term prognosis of treated phenylketonuria is still under discussion. We investigated the neurological outcome of 57 (24 male, 33 female) patients with phenylketonuria (diet onset 〈3 months) at a mean age of 23.6 (17–33) years in comparison to control subjects. Methods used were a clinical-neurological examination, tests for fine motor abilities, IQ test (WAIS-R), a neuropsychological attention task and MRI (30 patients only). Tremor was increased in the patients (28%) compared to controls (15%). Fine motor abilities were significantly reduced in three areas: hand-wrist steadiness, finger-hand dexterity and hand-wrist speed. Tremor as well as reduced fine motor skills were not associated with treatment-related variables, e.g. diet onset, strictness of biochemical control or amount of MRI white matter change. IQ was lower in patients (mean 97.6) compared to matched control subjects (mean 105.5). IQ at 12 years was correlated with biochemical control from birth up to the age of 12 and remained stable up to adult age, independent of biochemical control after 12 years of age. In contrast to the other outcome parameters, the performance in a neuropsychological attention task was influenced by the concurrent plasma phenylalanine concentration. Specific late-onset neurological impairment was not identified in this sample of early-treated adults with phenylketonuria. Conclusion Careful neurological investigation revealed subtle symptoms of brain damage even after early-initiated treatment in adult patients with phenylketonuria. At present it cannot be excluded that further neurological deterioration could emerge later in life. Thus, patients with phenylketonuria – either on or off diet – should be monitored throughout life.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 3 (1994), S. 189-197 
    ISSN: 1573-4846
    Keywords: nanocomposites ; sol-gel ; heteropolymetalates ; photochromics ; electrochemical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract New nanocomposites materials have been synthesized. They present electrochemical and photochromic properties. They are based on a hybrid organic-inorganic network, in which tungsten heteropolyoxometalates (PW12O 40 3− , SiW12O 40 4− , W10O 32 4− , polymeric tungstate) are entrapped. High tungsten ratios could be reached and films or bulk materials have been obtained. The structure of these materials is described on the basis of multi-spectroscopic investigations (IR, EPR, NMR). Electrochemical redox reactions have been observed in thin films. Dark blue reversible coloration of the materials is obtained under UV irradiation. The photochromic mechanism has been investigated and shows the reversible formation of carbonyl group.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 8 (1997), S. 927-929 
    ISSN: 1573-4846
    Keywords: organic-inorganic hybrids ; sol-gel ; photochromic performance ; spirooxazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Organic-inorganic hybrid materials synthesized via sol-gel processing are excellent solid matrices for photochromic dyes like spirooxazine, and the photochromic performance can be further enhanced by introducing suitable additives. This work describes the effects of additives on the photochromic intensity (Δ A 0), decolouration rate (k) and photostability of spirooxazine in sol-gel derived organic-inorganic hybrid matrices. They include fluoro-alkylsilane (FAS), bisphenol A (BPA) and methyl-imidazole (MI). FAS enhances both Δ A 0 and photostability, but has little effect on k. The higher the content of BPA, the higher the Δ A 0 and the higher the photostability, but the lower the k. The effect of MI on Δ A 0 and k is not so considerable as that of BPA and is a little complicated, while significant improvement in photostability is achieved by the addition of MI at an optimum concentration with the presence of BPA at a higher content.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 8 (1997), S. 927-929 
    ISSN: 1573-4846
    Keywords: organic-inorganic hybrids ; sol-gel ; photochromic performance ; spirooxazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Organic-inorganic hybrid materials synthesized via sol-gel processing are excellent solid matrices for photochromic dyes like spirooxazine, and the photochromic performance can be further enhanced by introducing suitable additives. This work describes the effects of additives on the photochromic intensity (ΔA 0), decolouration rate (k) and photostability of spirooxazine in sol-gel derived organic-inorganic hybrid matrices. They include fluoroalkylsilane (FAS), bisphenolA (BPA) and methyl-imidazole (MI). FAS enhances both ΔA 0 and photostability, but has little effect onk. The higher the content of BPA, the higher the ΔA 0 and the higher the photostability, but the lower thek. The effect of MI on ΔA 0 andk is not so considerable as that of BPA and is a little complicated, while significant improvement in photostability is achieved by the addition of MI at an optimum concentration with the presence of BPA at a higher content.
    Type of Medium: Electronic Resource
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  • 8
    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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  • 9
    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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  • 10
    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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