Electrochemical flow-through detector for the determination of cystine and related compounds

An electrochemical double cell for the detection of cystine in aqueous liquid streams is described. A column electrode of amalgamated silver powder is used to reduce cystine quantitatively to cysteine, which is detected amperometrically at a mercury electrode. The double cell is applied to the detection of cystine, cysteine and penicillamine in high-pressure liquid chromatography and to the selective determination of cystine and cysteine by flow-injection analysis.     

Forcing axioms and the continuum hypothesis

Woodin has demonstrated that, in the presence of large cardinals, there is a single model of ZFC which is maximal for Π₂-sentences over the structure (H(ω ₂), ∈, NS _ω1), in the sense that its (H(ω ₂), ∈, NS _ω1) satisfies every Π₂-sentence σ for which (H(ω ₂), ∈, NS _ω1) ? σ can be forced by set-forcing. In this paper we answer a question of Woodin by showing that there are two Π₂-sentences over the structure (H(ω ₂), ∈, ω ₁) which can each be forced to hold along with the continuum hypothesis, but whose conjunction implies $ {2^{{{\aleph_0}}}}={2^{{{\aleph_1}}}} $ . In the process we establish that there are two preservation theorems for not introducing new real numbers by a countable support iterated forcing which cannot be subsumed into a single preservation theorem.     

Neutral carrier based ion-selective electrode for the determination of Na+ in urine

Summary A Na⁺-selective PVC-membrane electrode which allows continuous measurement of Na⁺-activities in undiluted urine samples is described. In view of routine clinical analysis and bedside monitoring in intensive care units a miniaturized electrode system has been developed. When the Na⁺-concentrations determined by ion selective electrodes are correlated with those obtained for the same samples via flame photometry and atomic absorption, the residual standard deviation is found to be ±4.5 mM over the 50 to 250 mM Na⁺ range.

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Elektrode, beruhend auf einem neutralen Carrier zur Na-Bestimmung in Harn

Zusammenfassung Eine Na⁺-selektive PVC-Membranelektrode wurde beschrieben, die die Bestimmung der Na⁺-Aktivität in unverdünnten Urinproben ermöglicht. Im Hinblick auf klinische Routineuntersuchungen sowie den Einsatz in Intensivstationen wurde ein miniaturisiertes Elektrodensystem entwickelt. Die Korrelation der mit ionenselektiven Elektroden ermittelten Meßwerte mit Ergebnissen der Flammenphotometrie und der Atomabsorptionsspektrometrie ergibt eine Standardabweichung um die Regressionsgerade von ±4,5 mM über den Na⁺-Konzentrationsbereich von 50÷250 mM.

     

Improvement of quality in the evaluation of radium isotopes 224,226,228Ra in oil scale samples

Elevated concentrations of the radium isotopes ^224,226,228Ra exist in the scale and produced water in oil exploration. The activity concentration of ²²⁶Ra was calculated from 186.2 keV peak with no usual spectral interference of 185.7 from ²³⁵U. The activity concentration of ²²⁸Ra was calculated from its first daughter product ²²⁸Ac using the 911.2 keV gamma rays since it is a pure beta emitter. The activity concentration of ²²⁴Ra was calculated from ²¹²Pb using the 238.6 keV gamma-ray and the secular equilibrium equation with ²²⁸Ra. The IAEA 448 (oil contaminated field soil) reference material was used as a quality control for ^226,228Ra and but was unreliable for ²²⁴Ra using ²¹²Pb.

     

On a convenient property about $${[\gamma]^{\aleph_0}}$$

There is a partial order \mathbbP{\mathbb{P}} preserving stationary subsets of ω ₁ and forcing that every partial order in the ground model V that collapses a sufficiently large ordinal to ω ₁ over V also collapses ω ₁ over V^\mathbbP{V^{\mathbb{P}}} . The proof of this uses a coding of reals into ordinals by proper forcing discovered by Justin Moore and a symmetric extension of the universe in which the Axiom of Choice fails. Also, using one feature of the proof of the above result together with an argument involving the stationary tower it is shown that sometimes, after adding one Cohen real c, there are, for every real a in V[c], sets A and B such that c is Cohen generic over both L[A] and L[B] but a is constructible from A together with B.     

Forcing notions in inner models

There is a partial order \({\mathbb{P}}\) preserving stationary subsets of ω ₁ and forcing that every partial order in the ground model V that collapses a sufficiently large ordinal to ω ₁ over V also collapses ω ₁ over \({V^{\mathbb{P}}}\) . The proof of this uses a coding of reals into ordinals by proper forcing discovered by Justin Moore and a symmetric extension of the universe in which the Axiom of Choice fails. Also, using one feature of the proof of the above result together with an argument involving the stationary tower it is shown that sometimes, after adding one Cohen real c, there are, for every real a in V[c], sets A and B such that c is Cohen generic over both L[A] and L[B] but a is constructible from A together with B.     

Determination of K+ in diluted and undiluted urine with ion-selective electrodes

Summary Polyvinylchloride liquid membrane electrodes based on valinomycin lead to low readings in the determination of K⁺ in undiluted urine because of anion interference. This interference is eliminated by instead incorporating valinomycin into silicone rubber. When K⁺-concentrations, as determined in undiluted urine by ion selective electrodes, are correlated with those obtained for the same samples by flame photometry, the residual standard deviation is found to be ±1.5 mM over the 20 to 170 mM K⁺ range.

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Bestimmung von K⁺ in verdünntem und unverdünntem Harn mit ionen-selektiven Elektroden

Zusammenfassung Bestimmungen von K⁺ in unverdünntem Harn mit auf Valinomycin beruhenden Polyvinylchlorid-Flüssigmembranelektroden ergeben systematisch zu tiefe Werte. Diese Abweichungen sind durch Anioneninterferenz bedingt und können durch den Einsatz von Silikongummi als Membranmatrix eliminiert werden. Die Korrelation der mit K⁺-selektiven Silikongummimembranen in unverdünntem Harn ermittelten Meßwerte mit Ergebnissen der Flammenphotometrie ergibt eine Standardabweichung um die Regressionsgerade von ±1,5 mM über den K⁺-Konzentrationsbereich von 20 bis 170 mM.