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  • 1
    ISSN: 1618-2650
    Keywords: Best. von Isoniazid, Oxalyldihydrazid, Hydrochinon, Resorcin, organ. Verbindungen ; coulometrische Titration ; Silber(II)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary Conditions are described for the efficient generation of silver(II) and the titration of organic compounds by electrogenerated silver(II). An electrolyte of 0.1 M silver nitrate and 5 M nitric acid at −10°C is used, with a gold generating anode and a current density of 1.5–5 mA/cm2. A potentiometric (platinum-S.C.E. pair) or biamperometric (platinum electrodes, 200 mV) end point detection is used. For potentiometric detection, the platinum electrode is preconditioned with AgO in nitric or by anodization. The compounds isoniazid, oxalyldihydrazide, hydroquinone, and resorcinol were titrated down to sub-milligram quantities with errors of 1–2%.
    Notes: Zusammenfassung Der verwendete Elektrolyt besteht aus 0,1 M Silbernitrat in 5 M Salpetersäure bei −10°C. Die Generatoranode besteht aus Gold (Stromdichte 1,5–5 mA/cm2). Die Bestimmung des Endpunkts erfolgt potentiometrisch (Pt/SKE) oder biamperometrisch (Pt-Elektroden, 200 mV). Für die potentiometrische Bestimmung wird die Indicatorelektrode mit einer Lösung von AgO in Salpetersäure oder durch elektrochemische Anodisierung vorbehandelt. Folgende Substanzen wurden bis herab in den sub-Milligramm-Bereich mit Fehlern von 1–2% titriert: Isoniazid, Oxalyldihydrazid, Hydrochinon, Resorcin.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of orofacial orthopedics 32 (1971), S. 197-204 
    ISSN: 1615-6714
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Autor erinnert an die Bedeutung der Gaumennaht-Trennung: Verbreiterung der oberen Skelettbasis und Begünstigung der nasalen Atmung. Das Bestehen einer langsamen Gaumennaht-Trennung (innerhalb von 4 bis 15 Monaten) wird mit der Methode der “orthodontischen Goniometrie” an den Umbildungen des Gaumens, an der Größenzunahme des Abstandes in der Fossa canina und an Hand von Röntgenaufnahmen mit senkrechtem Strahleneinfall nachgewiesen. Durch sie ist es möglich, transversale Okklusionsunterbrechungen zu vermeiden. Anschließend beschreibt der Autor die Ultra-Schnell-Trennung unter Lokalanästhesie in einer bis drei Sitzungen für Patienten, deren Wohnsitz weiter entfernt liegt. Danach werden die Verbesserungen an Geräten vom Typ “Disjoncteur” behandelt —mit dem Zweck, Okklusionsunterbrechungen zu vermeiden und sie einfacher zu verschließen. Schließlich wird in diesem Artikel eine neue vereinfachte Methode zur Schnell-Trennung der Gaumennaht vor dem II. Lebensjahr dargelegt. Sie erfolgt mittels einer geschlitzten Gaumenplatte, die von nur zwei Ringen gehalten wird und die vom Gerät unabhängig sind.
    Abstract: Summary The Author reminds interest of disjunctions: widen upper skeletal base and make nasal breathing easier. Slow disjunctions (4 to 15 months) are proved by “orthodontic goniometry” method, palate transformations, canine-interfossal distance increasing, and vertical incidence radiographies. They avoid transversal occlusion breakings. Then the Writer describes ultra-fast disjunctions, with local anaesthesia, in 1 to 3 times, for patients living far. Then are described improvements added to “Disjunctor” type appliances to avoid occlusion breakings, and to seal them easier. At last the report indicates a simplified new method for fast disjunctions before the age of 11, with a split palatin plate supported by only 2 bands, independent of the appliance.
    Notes: Résumé L'auteur rappelle l'intérêt des disjonctions: élargir la base squelettique supérieure et favoriser la respiration nasale. L'existence de Disjonctions Lentes (en 4 à 15 mois) est prouvée par la méthode de «goniométrie orthodontique», les transformations du palais, l'augmentation de la distance interfosse-canine et les radiographies en incidence verticale. Elles permettent d'éviter les ruptures d'occlusion transversale. Puis l'auteur décrit la Disjonction Ultra-rapide, sous anesthésie locale, en une à trois séances, pour les patients habitant loin. Puis sont décrits des perfectionnements apportés aux appareils de type «Disjoncteur» pour éviter les ruptures d'occlusion, et pour les sceller plus facilement. Enfin l'article expose une nouvelle méthode simplifiée pour la disjonction rapide avant 11 ans, à l'aide d'une plaque palatine fendue soutenue par deux bagues seulement, indépendantes de l'appareil.
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  • 3
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Geological standards are analyzed using PIXE and PIGE techniques. The concentrations of up to 26 elements are determined and compared with those obtained by other methods. PIXE and PIGE techniques are also applied to different volcanic rock samples. Their sensitivity, accuracy, and speed of data collection and reduction, are of great interest in the study of volcanic phenomena.
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  • 4
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Aclacinomycin bzw. Aclarubicin (D. C. L), ein neues Cytostaticum aus der Anthracyclingruppe, wurde unter Verwendung der d. c-, a. c- und d. p.-Polarographie und der zyklischen Voltammetrie untersucht. Die Reduktion der chinoiden Struktur dieser Verbindung ist die Ursache einer gut ausgebildeten 2-Elektronen-Welle zwischen -0,22 und -0,80 V gegen eine ges. Kalomelelektrode zwischen pH 1,0 und 13,0. Die Umkehrbarkeit dieses elektrochemischen Vorganges ist geringer als die eines einfachen Chinonderivates und ist pH-unabhängig. Manche Adsorptionserscheinungen können stören. Das Reduktionsprodukt wird an der Hg-Elektrode adsorbiert und dürfte die voltamperometrische Reaktion hindern. An der Kohlenstoffbrei-Elektrode gibt Aclacinomycin eine anodische Welle, die der Oxydation einer der phenolischen Gruppen des Anthrachinonrestes zugeschrieben werden könnte. Die quantitative Bestimmung von Aclacinomycin wurde in gepuffertem Medium bei pH 6 durchgeführt. Im Konzentrationsbereich 10−3 bis 10−5 M wurde gute Linearität festgestellt. Sowohl in alkalischem Medium wie bei Belichtung ist die Stabilität von Aclacinomycin deutlich besser als die anderer Chinonderivate.
    Notes: Summary Aclacinomycin or aclarubicin (D. C. I.), a new cytostatic agent related to the anthracyclin group, has been investigated using d. c., a. c. and d. p. polarographic techniques and cyclic voltammetry. The reduction of the quinonic structure of this compound gives rise to a well defined two-electron wave between -0.22 V and-0.80 V vs. S. C. E. for a pH range from 1.0 to 13.0. The reversibility of this electrochemical process is lower than that of a simple quinonic derivative and is pH independent. Some adsorption phenomena may interfere. The reduction product is adsorbed at the mercury electrode and may partially inhibit the voltamperometric response. At a carbon paste electrode, aclacinomycin shows an anodic wave which may be assigned to the oxidation of one of the phenolic function of the anthraquinonic nucleus. Quantitative determinations of aclacinomycin were carried out in a pH 6 buffered medium. A very good linearity was observed in the 1×10−3 to 1×10−5 M concentration range. The stability of aclacinomycin is significantly better than that of other quinonic derivatives both in alkaline medium and under light effect.
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  • 5
    ISSN: 1573-4978
    Keywords: cancer cells ; differentiation ; prosome/proteasome ; cell growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The core of the 26S proteasome, the 20S prosome, is a highly organized multi-protein complex found in large amount in malignant cells. Differentiation of several cell lines, including the monoblastic U937 and the lymphoblastoid CCRF-CEM, is accompanied by a general decrease in the prosome concentration when phorbol-myrirtic-acetate (PMA) and retinoic acid plus dihydroxyvitamine D3 (RA+VD) are used. Incubation of U937 cells for three days with PMA or RA+VD causes differentiation, but the resulting patterns of prosome labeling in the cell and on the plasma membrane are not the same. In contrast, the same kind of prosome changes occur in U937 and CCRF-CEM cells when PMA is used as inducer. The intracellular distribution of prosomes is also linked to malignancy and differentiation. Prosomes are found in the nucleus and the cytoplasm of cancer cells; and treatment with RA+VD decreases the prosomes in the nucleus whereas PMA causes various prosome proteins changes. These results indicate that prosomes are important in cell regulation and in the expression of malignancy.
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  • 6
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Oxydation von organischen Verbindungen wie Hydrochinon, p-Aminophenol, N-Acetyl-p-aminophenol und N-Acetyl-p-phenetidin wurde coulometrisch mit Cer(IV) und Mangan(III) durchgeführt. Auch im Mikromaßstab erhält man ausgezeichnete Ergebnisse.
    Abstract: Summary Coulometric Microdetermination of Organic Compounds With Manganese(IIl) and Cerium(IV) The oxidation of compounds such as hydroquinon, p-aminophenol, paracetamol and phenacetin was performed using cerium(IV) and manganese(III) coulometrically electrogenerated. Quantitative results obtained are excellent even at the microscale level.
    Notes: Résumé L'oxydation de composés tels que l'hydroquinone, lep-aminophénol, le N-acétylp-aminophénol (paracétamol) et le N-acétylp-phénétidine (phénacétine) a été réalisée électrolytiquement par le manganèse trivalent et le cérium tétravalent. Les résultats quantitatifs obtenus sont très satisfaisants et permettent le dosage coulométrique à l'échelon microanalytique.
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  • 7
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung An der Elektrode entwickeltes AuCl4− in 0,02M HCl wurde für die Titration von Hydrochinon, Ascorbinsäure, Phenylhydrazin, Phenelzinsulfat und Phenylsemicarbazid mit biamperometrischer Endpunktanzeige verwendet. Die Ergebnisse wurden mitgeteilt und mit den Resultaten der Coulometrie mit Cersulfatoxydation verglichen. Im Gegensatz dazu können mit weniger als 1 mg Probe in derselben Lösung Folgetitrationen durchgeführt werden. Abweichend von seinem Verhalten gegenüber stärkeren Oxydationsmitteln reagiert Phenelzinsulfat stöchiometrisch.
    Notes: Summary Electrogenerated AuCl4− in 0.02M HCl is used to titrate hydroquinone, ascorbic acid, phenylhydrazine, phenelzine sulphate and phenylsemicarbazide, with biamperometric end-point detection. Titration recoveries are reported and compared with results of coulometry with ceric sulphate oxidation. With less than 1 mg of sample, successive titrations can be performed in the same solution, in contrast to coulometry with ceric sulphate. Phenelzine sulphate reacts stoichiometrically, as opposed to its reactions with stronger oxidizing agents.
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  • 8
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The use of dispersion techniques for development of microwave absorbers is a convenient way of realization of coatings with good attenuation characteristics in the 1- to 20-GHz range. Particularly, elastomer mixing is a very good technique for dispersion and individualization of each grain up to 60% volume. A first generation of materials, developed with ferrite powders, has been extensively studied. It was found possible to predict properties of composites with classical mixture laws using intrinsic properties of filler and matrix. When using conductive ferromagnetic fillers, the inability to measure intrinsic magnetic properties does not permit prediction of behavior of composites. Therefore, a method of inverse calculation has been developed which, from (ε, μ) parameters measured on composites, allows inferrence of intrinsic properties of each filler (iron, cobalt, permalloy,...). It is shown that this method, employed for several amounts of filler, gives significant accuracy on (μ', μ‘) with intermediate concentrations (typically 25% vol. to 45% vol. with spheres). For permittivity, this method is satisfying in the case of nonpercolating systems. Also studied was the effect of morphology on properties of granular materials, particularly in the case of sphericity and grain size of iron and cobalt particles. Permittivity level is directly correlated to sphericity, and magnetic relaxation frequency to grain size. It is also shown that the chemical nature, particularly for ex-carbonyl origin of iron, does not play a significant role in composite material properties.
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 366-372 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The 0.255 A(ring)/kbar linear pressure shift of the intense, narrow, and well-isolated 5D0-7F0 (named 0-0) emission line of SrB4O7:Sm2+ (at 6854.1 A(ring) in ambient conditions) is proposed as a new optical pressure gauge for the diamond anvil cell. The pressure determinations can be made with the same experimental devices as those currently used for the ruby sensor. The good accuracy results from the singlet character and a small linewidth which is no more than 2.5 A(ring) up to 200 kbar in a 4:1 methanol:ethanol mixture, provided the linewidth is "relaxed'' through thermal cycles. Such a process can probably be of general interest for this purpose. In nonisostatic media, a similar pressure coefficient and a broadening of ∼0.1 A(ring)/kbar are obtained. This broadening does not greatly disturb the pressure measurements, at least up to 200 kbar. High-pressure determinations up to 400 °C are also shown to be more accurate than with the ruby, owing to the very limited temperature effect on the wavelength (−0.001 A(ring)/°C) and linewidth (∼0.005 A(ring)/°C) of the 0-0 line. The other characteristics of the emission spectrum of SrB4O7:Sm2+ are promising for (a) simultaneous measurements of pressure and temperature (at least up to 400 °C) using this same material and (b) further research on other rare-earth-doped compounds. The possibility of pressure coefficients larger than that of the R1 ruby line is shown by the 0.45 A(ring)/kbar value measured for another emission line of SrB4O7:Sm2+.
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  • 10
    ISSN: 1439-6327
    Keywords: Altitude ; Hypobaric chamber ; Physical training ; Aerobic metabolism ; Erythropoiesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of training in a hypobaric chamber on aerobic metabolism were studied in five high performance triathletes. During 3 weeks, the subjects modified their usual training schedule (approximately 30 h a week), replacing three sessions of bicycling exercise by three sessions on a cycle ergometer in a hypobaric chamber simulating an altitude of 4,000 m (462 mm Hg). Prior to and after training in the hypobaric chamber the triathletes performed maximal and submaximal exercise in normoxia and hypoxia (462 mm Hg). Respiratory and cardiac parameters were recorded during exercise. Lactacidaemia was measured during maximal exercise. Blood samples were drawn once a week to monitor blood cell parameters and erythropoetin concentrations. Training in the hypobaric chamber had no effect on erythropoiesis, the concentrations of erythropoetin always remaining unchanged, and no effect on the maximal oxygen uptake ( $$\dot V$$ O2max) and maximal aerobic capacity measured in normoxia or hypoxia. Submaximal performance increased by 34% during a submaximal exhausting exercise performed at a simulated altitude of 2,000 m. During a submaximal nonexhausting test, ventilation values tended to decrease for similar exercise intensities after training in hypoxia. The changes in these parameters and the improved performance found for submaximal exercise may have been the result of changes taking place in muscle tissue or the result of training the respiratory muscles.
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