Ramsey numbers for a disjoint union of good graphs

We give the Ramsey number for a disjoint union of some G-good graphs versus a graph G generalizing the results of Stahl (1975) [5] and Baskoro et al. (2006) [1] and the previous result of the author Bielak (2009) [2]. Moreover, a family of G-good graphs with s(G)>1 is presented.     

Estimation and status prediction in a discrete mover‐stayer model with covariate effects on stayer's probability

A discrete‐time mover‐stayer (MS) model is an extension of a discrete‐time Markov chain, which assumes a simple form of population heterogeneity. The individuals in the population are either stayers, who never leave their initial states or movers who move according to a Markov chain. We, in turn, propose an extension of the MS model by specifying the stayer's probability as a logistic function of an individual's covariates. Such extension has been recently discussed for a continuous time MS but has not been considered before for a discrete time one. This extension allows for an in‐sample classification of subjects who never left their initial states into stayers or movers. The parameters of an extended MS model are estimated using the expectation‐maximization algorithm. A novel bootstrap procedure is proposed for out of sample validation of the in‐sample classification. The bootstrap procedure is also applied to validate the in‐sample classification with respect to a more general dichotomy than the MS one. The developed methods are illustrated with the data set on installment loans. But they can be applied more broadly in credit risk area, where prediction of creditworthiness of a loan borrower or lessee is of major interest.     

The X-ray revision of the structure of bis(4-hydroxybenzhydrazide)copper(II) sulfate(VI) dihydrate and its vibrational spectroscopy

The structure of known copper(II) complex with 4-hydroxybenzoic acid hydrazide has been corrected on the basis of a new X-ray analysis. It has been found, that the sulfate(VI) ion is bonded in apical position of Cu(II) coordination pyramid having two organic ligands at the base. Two water molecules are not coordinated as has been postulated before, but stabilizes the sulfate(VI) group orientation and link the layers of complex molecules by strong hydrogen bonds. The detailed interpretation of the measured IR and Raman spectra has been performed with aid of both: quantum calculations as well as H/D and ⁶³Cu–⁶⁵Cu isotope substitution.     

Komplexbildende Eigenschaften des 3,5-Dimethylpyrazols. II

Zusammenfassung Die Bedingungen der Entstehung und der Extraktion der aus Cu²⁺, Rhodanid und 3,5-Dimethylpyrazol entstehenden Komplexe wurden untersucht. Mittels optischer Untersuchungen wurde bewiesen, daß sich aus diesen Komponenten Triplettkomplexe mit verschiedener Koordinationszahl bilden. Chloroform extrahiert einen Komplex mit der Formel [Cu(CNS)₂(DMP)₂], Benzol dagegen einen Komplex mit der Formel [Cu(CNS)₂(DMP)₄].

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Summary The conditions for the production and the extraction of complexes formed in the Cu-SCN-DMP system were examined. Optical studies revealed that this system gives rise to triplet complexes with various coordination numbers. Chloroform extracts a complex whose formula is [Cu(SCN)₂(DMP)₂]. On the other hand, benzene extracts a complex with the formula [Cu(SCN)₂(DMP)₄].

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Résumé On a fait l'étude expérimentale des conditions de formation et d'extraction du complexe qui se forme avec le système Cu/SCN/DMP. Il s'est révélé qu'un complexe triple se formait pour ce système avec un nombre différent de coordination. Le chloroforme extrait un complexe de formule [Cu(SCN)₂(DMP)₂], le benzène, par contre, un complexe de formule [Cu(SCN)₂(DMP)₄].

     

Die Anwendung von β-Dithionaphtholsäure zur kolorimetrischen Nickelbestimmung

Zusammenfassung -Dithionaphtholsäure hat komplexbildende Eigenschaften. Der Nickelkomplex löst sich in Äthanol mit violetter Farbe. Seine Zusammensetzung entspricht der Formel (HOC₁₀H₆CS₂)₂Ni. Der Komplex kann zur kolorimetrischen Nickelbestimmung in den Konzentrationsgrenzen 0,20 bis 3,00g/ml verwendet werden.

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Summary -Dithionicnaphthol acid has complex-forming properties. The nickel complex dissolves in ethanol to give a violet color. Its composition corresponds to the formula (HOC₁₀H₆CS₂)₂Ni. The complex may be used for the colorimetric determination of nickel within the concentration ranges from 0.20 to 3.00g/ml.

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Résumé L'acide -dithionaphtylique possède des propriétés complexantes. Le complexe du nickel se dissout dans l'éthanol en donnant une coloration violette. Sa composition correspond à la formule (HOC₁₀H₆CS₂)₂Ni. On peut l'utiliser pour le dosage colorimétrique du nickel dans le domaine des concentrations 0,20–3,00g/ml.

     

Chromatographic analysis of penstemide and serrulatoloside by high-performance liquid chromatography and gradient thin-layer chromatography

Summary A sensitive capillary gas chromatographic method is described for the simultaneous determination of lidocaine, tetracaine, procaine and dibucaine. The method was applied to the determination of anesthetics in tissue homogenates incubated at 38°C at doses between 10 and 400 mg/kg. In the liver tissue thein vitro metabolization of the studied anesthetics is most rapid for tetracaine, also fast for procaine, while for lidocaine and dibucaine the metabolization is very slow. In brain tissue thein vitro metabolization of anesthetics is very slow.The method shows good analytical parameters: linearity between 5 and 40 g/ml; day-to-day reproducibility ca. 8% for a concentration of 20 g/ml, precision ca. 7% for a concentration of 20g/ml. Accuracy is also very good.     

Benzofuran systems. Regioselective bromination and some other reactions of 1-(3-benzofuranyl)-2-phenylethanones

1-[3-(2-Alkylbenzofuranyl)]-2-(3,5-dibromo-4-hydroxyphenyl)ethanones 5a,b and 1-[3-(2-alkylbenzofuranyl)-2-(3-bromo-4-methoxyphenyl)ethanones 3a,b were readily prepared by selective bromination of hydroxy 1a,b and methoxy 1c,d ethanones, respectively. A successful method of O-alkylamination of 5a with N-(2-chloroethyl)-N,N-diethylammonium chloride to 6a by a two-phase reaction under phase transfer conditions has been applied. Lithium aluminium hydride reduction of the carbonyl group of 1b to carbinol 4b was carried out in good yields.     

Composite ion exchanger for removal of sodium-24 from mineralizates of biological materials in neutron activation analysis

A composite ion exchanger containing hydrated antimony pentoxide (HAP) in polystyrene-divinylbenzene matrix has been prepared. Its sorption properties with respect to Na, As, Au, Cd, Cu, Ga, Hg, In, K, La, Mn, Mo (Tc), Pd, Pt, Sb, W and Zn have been examined. Sodium is quantitatively retained on the sorbent from 8M HCl solution as well as from a mixture of conc. H₂SO₄+ conc. HNO₃+H₂O (1+1+2). As, W, Cd and Sb are partially retained, while the remaining elements are not retained and can be quantitatively eluted. The composite ion exchanger is stable to oxidizing acid media and it can be directly applied to separation of²⁴Na from mineralizates of neutron-irradiated biological materials.     

Effect of phenyltin compounds on lipid bilayer organization

Phenyltin compounds are known to be biologically active. Their chemical structure suggests that they are likely to interact with the lipid fraction of cell membranes. Using fluorescence and NMR techniques, the effect of phenyltin compounds on selected regions of model lipid bilayers formed from phosphatidylcholine was studied. The polarization of N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) dipalmitoyl-L -phosphatidylethanolamine and desorption of praseodymium ions was used to probe the polar region, whereas the polarization of 1 - (4 - trimethylammoniumphenyl) - 6 - phenyl - 1,3,5-hexatriene p-toluenesulfonate measured the hydrophobic core of the membrane. In addition, changes in the N-(5-fluoresceinthiocarbanoly)dipalmitoyl - L - α - phosphatidyl - ethanolamine fluorescence intensity indicated the amount of charge introduced by organotin compounds to the membrane surface. There were no relevant changes of measured parameters when tetraphenyltin was introduced to the vesicle suspension. Diphenyltin chloride causes changes of the hydrophobic region, whereas the triphenyltin chloride seems to adsorb in the headgroup region of the lipid bilayer. When the hemolytic activity of phenyltin compounds was measured, triphenyltin chloride was the most effective whereas diphenyltin chloride was much less effective. Tetraphenyltin causes little damage. Based on the presented data, a correlation between activity of those compounds to hemolysis (and toxicity) and the location of the compound within the lipid bilayer could be proposed. In order to inflict damage on the plasma membrane, the compound has to penetrate the lipid bilayer. Tetraphenyltin does not partition into the lipid fraction; therefore its destructive effect is negligible. The partition of the compound into the lipid phase is not sufficient enough, by itself, to change the structure of the lipid bilayer to a biologically relevant degree. The hemolytic potency seems to be dependent on the location of the compound within the lipid bilayer. Triphenyltin chloride which adsorbs on the surface of the membrane, causes a high level of hemolysis, whereas diphenyltin chloride, which penetrates much deeper, seems to have only limited potency. © 1998 John Wiley & Sons, Ltd.