Anwendung coulometrischer Titrationen auf die klinische und toxikologische Analyse

Zusammenfassung Die Theorie der coulometrischen Titration wird unter besonderer Berücksichtigung von Titrationsmitteln, Endpunktsbestimmungen, Empfindlichkeit, Genauigkeit und Zuverlässigkeit diskutiert. Die Vor- und Nachteile der Technik werden erläutert. Eine Übersicht über die Anwendung der coulometrischen Titration in der klinischen und toxikologischen Analyse wird gegeben, wobei besonders auf die Bestimmung von Gesamteiweiß, Harnstoffstickstoff und Glucose im Serum und von Thallium und Arsen in Urin aufmerksam gemacht wird.

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Application of coulometric titration to clinical and toxicological analysis

The theory of coulometric titrations is discussed with special reference to titrants, end-point detection, sensitivity, precision, and accuracy. The advantages and disadvantages of the technique are enumerated. Applications of coulometric titrations to clinical and toxicological analysis are reviewed with particular attention to the determination of total protein, urea nitrogen, and glucose in serum and to arsenic and thallium in urine.

     

Room-temperature luminescence of benzo[f]quinoline, p-aminobenzoic acid, phenanthrene, and 4-phenylphenol on a variety of solid surfaces

Analytical figures of merit for the room-temperature luminescence of four model compounds with quite different chemical structures were compared. The compounds were adsorbed on four different surfaces that have been employed recently in solid-surface luminescence analysis. The solid materials investigated were silica gel with a polyacrylate binder, filter paper, 1% polyacrylic acid-NaBr, and 80% α-cyclodextrin-NaCl. The experimental conditions were optimized to give enhanced luminescence signals. In some cases, filter paper and 80% α-cyclodextrin-NaCl gave comparable analytical results. However, filter paper gave the best overall results.     

How often is a polygon bounded by three sides?

LetL _n be the set of lines (no two parallel) determining ann-sided bounded faceF in the Euclidean plane. We show that the number,f(L _n), of triples fromL _n that determine a triangle containingF satisfies and these bounds are best. This result is generalized tod-dimensional Euclidean space (without the claim that the upper bound is attainable).     

Synthesis,crystal structure,and reactivity of alkali and silver salts of sulfonated imidazoles

Both 2-methylimidazole and 2-ethyl-4-methylimidazole were monosulfonated with oleum in the five position. In crystals of the monohydrate of 2-methylimidazole-5-sulfonic acid, hydrogen bonds link the molecules into a 3-dimensional network, while in crystals of 2-ethyl-4-methylimidazole-5-sulfonic acid, corrugated 2-dimensional layers are present. The Li and Ag salts and the bis(trimethylsilyl) derivatives of 2-ethyl-4-methylimidazole-5-sulfonic acid were prepared, and there is evidence for doubly deprotonated imidazolesulfonate in aqueous solution. The monohydrate of the Li salt and the Ag salt also form a 3-dimensional, H-bonded network. Only in the Ag salt does the asymmetric unit consist of more than one basic formula unit. One Ag atom is 2-coordinate and links two nitrogen atoms, while the other Ag atom has distorted tetrahedral coordination and links the sulfonate groups into an infinite chain. Reactions of the silver salt with 1,4-dibromobutane in non-protic solvents such as 1-methyl-2-pyrrolidone were used to link two of the imidazolesulfonic acid units with a 4-carbon chain at the nitrogens.     

A collaboratory for radiation therapy treatment planning optimization research

Intensity modulated radiation therapy treatment planning (IMRTP) is a challenging application of optimization technology. We present software tools to facilitate IMRTP research by computational scientists who may not have convenient access to radiotherapy treatment planning systems. The tools, developed within Matlab and CERR (computational environment for radiotherapy research), allow convenient access, visualization, programmable manipulation, and sharing of patient treatment planning data, as well as convenient generation of dosimetric data needed as input for treatment plan optimization research. CERR/Matlab also provides a common framework for storing, reviewing, sharing, and comparing optimized dose distributions from multiple researchers.     

Bose-Einstein condensation in a circular waveguide

We have produced Bose-Einstein condensates in a ring-shaped magnetic waveguide. The few-millimeter diameter, nonzero-bias ring is formed from a time-averaged quadrupole ring. Condensates that propagate around the ring make several revolutions within the time it takes for them to expand to fill the ring. The ring shape is ideally suited for studies of vorticity in a multiply connected geometry and is promising as a rotation sensor.     

Summing over a network without revealing summands

Consider a network in which each node possesses a secret member of a finite abelian group. In this paper we present a protocol by which the nodes can compute the sums of their secret elements without revealing them to each other. The security against discovery of the secret values as a result of conspiracies among nodes or compromise of channels between nodes is shown to depend on the connectivity of the graph defined by the network. Moreover, we are able to quantify exactly the amount of information revealed as a result of a conspiracy of a given set of nodes or compromise of a given set of channels.     

Preparation of Phase Pure Cubic Gallium Nitride, c-GaN, by Ammonothermal Conversion of Gallium Imide, {Ga(NH)3/2} n

Gallium imide, {Ga(NH)_3/2} _n , was sealed in quartz tubes with anhydrous NH₃ and NH₄X (X=Cl, Br, I) and heated vertically in an autoclave with the hot-zone (bottom) temperature ranging from 300–530°C. With NH₄I mineralizer, the imide was converted to primarily the zinc-blende phase of GaN (c-GaN), usually in the form of micron sized or smaller tetrahedra. With NH₄Cl mineralizer, hexagonal GaN nanoparticles formed instead, and NH₄Br facilitated the conversion of imide to irregular h-GaN nanoparticles at lower temperatures, and larger particles above 500°C. At the higher temperatures, chemical transport took place and GaN crystals grew on the walls at the middle to the top of the tube. Most of the deposited GaN was cubic, usually in a heavily etched triangular prismatic morphology. Several experiments were performed in a Pt lined pressure vessel in order to demonstrate that the synthesis method can be scaled up.