bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamics of reacting mixtures for micropolar fluids
Authors: Říha Pavel
Published: October 2011

The balance laws and linear constitutive equations of the theory of reacting mixtures for micropolar fluids are derived. Theoretical relations include the assumptions that the elements of micropolar fluids do not undergo deformations and have different temperature and concentration fields of constituents of the mixture. The theory is developed for prediction of flow, heat and mass transfer in fluid suspensions. Diffusion through the layer of fluid suspension is studied as the example.
Batch reactor with closed system of the coolant. General analysis
Authors: Horák Josef , Jiráček František , Šimůnek Ivan
Published: October 2011

The methods are proposed for studies on behaviour of periodically operated batch and semibatch reactors with the coupling between individual operating cycles and continuous reactors controlled by step changes of inlet quantities. The methods are based on numerical and graphical procedures. Examples are given on application of these methods to studies on the character and stability of steady cycles of the batch reactor with the closed bath of the coolant (heat carrier) at exothermic first order reaction. The reactor together with the bath of the coolant is operated autothermally.
Mercury(II) complexes with phosphineacetic acids
Authors: Podlahová Jana , Podlaha Jaroslav
Published: October 2011

Mercury(II) forms very stable water-soluble complexes with metal-to-ligand ratios of 1 : 1, 1 : 2 and 1 : 3 with phosphineacetic acids of the general formula Ph3-nP(CH2COOH)n (n = 1-3). At n = 1 formation of the further 1 : 4 complex was detected. Stability constants of the complexes were determined polarographically and potentiometrically (mercury electrode) in water and in 50% v/v dioxan at I 0.1 (NaClO4) and 25 °C. Protonation of the complexes as followed from pH-titrations and IR spectra demonstrated that the ligands are monodentate through phosphorus. The ability to form higher complexes (L/Hg > 2) strongly decreases with increasing charge on the ligand anion.
Estimation of the stability of complex hydrides by a pattern-recognition classification method
Authors: Fusek Jiří , Štrouf Oldřich
Published: October 2011

The ABHnD4-n complex hydrides (A = alkali metal, B = the IIIB Group atom, n = number of hydride atoms and D = ligand) were classified as stable or unstable ones by a pattern - recognition method. The method is based on a measure of similarity which is represented by the ratio of squared distance of the object from the centre of the class and the averaged squared distance of this centre from all prototypes in the class. The distances are measured in transformed and normalized spaces for each class, the individual class approaching a hypercube with an edge length (standard deviation) of one. The results are directly compared with those previously obtained by SIMCA principal components method using the same data base (MODEL-1).
Chromatography of anions on silica gel thin layer
Authors: Beneš Jaroslav
Published: October 2011

The paper gives results of investigation of behaviour of the anions PO43-, MoO42-, TcO4-, RuO42-, TeO32- and (in part) I- during thin-layer chromatography with silica gel adsorbent and mixtures of alcohols with aqueous ammonia as eluent systems. For migrating anions the RF changes due to changes of the organic to aqueous phase ratio, analytical concentration of ammonium ions, the alcohol used in the eluent system, and concentration of the anions in solutions of samples have been determined. Correlation between RF of the anions and dielectric constant of the eluent systems have been followed; relation between the both variables can be expressed by approximative equation RF = k log ε + log q.
Spectral properties of zeromethinemerocyanines
Authors: Vávrová Jaroslava , Vávra Miloš , Babák Zdeněk
Published: October 2011

Twenty six zeromethinemerocyanine dyes III were prepared by condensation of carbonylmethylene group containing heterocycles II with nitrogen-containing 2-alkylmercapto heterocycles I. Their absorption maxima in the visible spectral region in ethanolic solution, as well as of the dyes adsorbed on silver halide, were measured. IR spectra in chloroform and in KBr were also studied.
Fourier component analysis of intramolecular interactions in α-carbofunctional silanes
Authors: Ponec Robert , Dejmek Luboš , Chvalovský Václav
Published: October 2011

Fourier analysis of potential curves of internal rotation around the C-X bond in α-carbofunctional organosilicon compounds of the type Y-CH2-X (X = NH2, OH; Y = SiH3, Si(CH3)3) has been used to study the character of intramolecular interactions in relation to the mechanism of the so-called α-effect. The results obtained are in accordance with previous conclusions based on the analysis of orbital correlation diagrams.
Participation of 19-ester groups in hypobromous acid additions to 2,3- and 5,6-unsaturated steroids
Authors: Kočovský Pavel , Černý Václav , Synáčková Miroslava
Published: October 2011

Hypobromous acid action upon the 2,3-unsaturated acetoxy derivative Ia results in the formation of two products, the bromohydrin IVa and the cyclic ether VI as a product of the participation of ether oxygen of the ester group. Both these compounds are formed from the 2α,3α-bromonium ion XIIIa. Under the same conditions the 5,6-unsaturated 19-acetoxy derivative IIa afforded a mixture of the following products: Bromohydrin Xa as the product of a normal reaction course and the isomeric bromohydrin VIIa arising by intramolecular interaction with the carbonyl oxygen of the 19-acetoxy group. Both these compounds are formed from the 5α,6α-bromonium ion XVIIIa. The epimeric 5β,6β-bromonium ion XVIIa gives rise to the bromohydrin XIa. The mechanism of these reactions, difference in behavior of both olefins I and II and the competition between ambident neighboring group participation and external nucleophile attack is discussed.
Kinetic analysis of coupled gas phase oxidation reaction of secondary alcohols on iridium
Authors: Slouka Pavel , Beránek Ludvík
Published: October 2011

Kinetics of partial gas phase oxidation of 2-butanol (B) and 4-methyl-2-pentanol (M) to ketones on Ir/C catalyst at 150 °C has been studied. In single reactions alcohol B was 4-7times more reactive than alcohol M, in competitive reactions the latter was twice as reactive as the former. Separate treatment of rate data for single and competitive reactions of both alcohols showed that each set could be described by nearly the same set of equations on 99% confidence level, including, of course, very different kinetic models. Confrontation of the kinetics of single and competitive reactions (comparison of the values of corresponding constants of rate equations) and the analysis of relative reactivities revealed the unfitness of Langmuir-Hinshelwood and redox models in this case. A model taking into account nonhomogeneity of the surface and a model derived on the basis of a chain mechanism would be able to describe better and in consistent way the kinetics of single and competitive reactions as well as the observed inversion of the reactivity of studied alcohols.
Synthesis of conjugates of 5-halouracils with proteins using activated esters
Authors: Pischel Helmut , Holý Antonín , Wagner Günther
Published: October 2011

1-Carboxymethyluracil (Ia) and its 5-fluoro (Ib), 5-bromo (Ic) and 5-iodo (Id) derivatives were transformed into the p-nitrophenyl esters IIa-IId by reaction with p-nitrophenol in the presence of N,N'-dicyclohexylcarbodiimide. Reaction of these compounds with ammonia or ε-aminocaproic acid afforded the corresponding 1-aminocarbonylmethyluracil (IIIa-d) and 1-N-(5-carboxypentyl)aminocarbonylmethyluracil (IVa-d) derivatives. Reaction of compounds II with human serum albumin and bovine γ-globulin at pH 9.2 gave high yields of conjugates of the type V and VI, respectively, containing 10-50 uracil derivative moieties bound to the protein molecule.
Effect of methylation of the hydroxyl group of tyrosine in [1-β-mercaptopropionic acid, 8-D-arginine]vasopressin on its biological effects
Authors: Krchňák Viktor , Zaoral Milan
Published: October 2011

Using the method of solid-phase synthesis, S-benzyl-β-mercaptopropionyl-O-methyltyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteinyl-prolyl-NG-p-toluenesulfonyl-D-arginyl-glycine amide (I) was prepared which after removal of the protecting groups, oxidation, and purification afforded [1-β-mercaptopropionic acid, 2-O-methyltyrosine, 8-D-arginine]vasopressin (II). II shows a low antidiuretic effect, c. 10 I.U./mg. It is without effect on rat uterus in vitro and on the blood pressure of rat in vitro.
The synthesis, spectral properties and pesticidal activity of O-(1-benzyl, cyclohexyl, methyl-5-ethoxy, methoxy, methylthio-6-oxo-1H-pyridazin-4-yl) esters of phosphoric, thiophosphoric and thiophosphonic acids
Authors: Konečný Václav , Varkonda Štefan
Published: October 2011

The synthesis of O-(5-ethoxy-1-methyl-6-oxo-1H-pyridazin-4-yl), O-(5-methoxy-1-benzyl-6-oxo-1H-pyridazin-4-yl), O-(5-methylthio-1-methyl-6-oxo-1H-pyridazin-4-yl) and O-(5-methoxy-1-cyclohexyl-6-oxo-1H-pyridazin-4-yl) esters of phosphoric, thiophosphoric and thiophosphonic acids is described. The IR and UV spectra of the synthetized compounds were measured and interpreted and their contact and systemic insecticidal, acaricidal and ovicidal activity was determined. Several of the compounds tested displayed high activity.
Preparation and reactions of 5,7-ditert-butyl-1,2-diphenylspiro[2,5]octa-1,4,7-trien-6-one: A revision of the literature
Authors: Pavlíčková Libuše , Souček Milan
Published: October 2011

The structure VIb, suggested previously on the basis of physico-chemical data for the compound reported to be the sole product of thermolysis of 2,6-ditert-butyl-4-diazo-2,5-cyclohexadien-1-one (IV) in the presence of diphenylacetylene, is incorrect. We have now shown that the main product is in fact 4-(3',5'-ditert-butyl-4'-hydroxybiphenyl)phenylacetylene (VIII). Other, minor, products of this reaction are the isomeric ketones VIIb and IX, the diphenoquinone XI and the cyclic azo compound XII. A small quantity of the spirotrienone VIb was isolated only when the reaction had been performed with a large excess of diphenylacetylene. The structure of VIb was determined unequivocally by physico-chemical methods and chemical transformations to compounds, prepared by independent syntheses. Air-oxidation of the ketone VIIb in an alkaline medium afforded the quinone methide X.
New possibilities of applications of the Barker quasi-lattice theory. Some relations between excess functions at infinite dilution
Authors: Dohnal Vladimír , Holub Robert , Pick Jiří
Published: October 2011

A relation for the limiting activity coefficient and for the partial excess enthalpy of binary solution was derived from the Barker quasi-lattice theory. On the basis of these equations we found the relations between γi##h or hiE ##h for some groups of related binary systems in an especially simple form so that is it possible to convert these quantities from one system to another without the evaluation or knowledge of adjustable energy parameters. For some predictions it is only necessary to choose a geometrical model of molecules involved in them. The relations were obtained for binary systems whose one component is formed by monotonous molecules varying in size (such as n-alkanes) and the other component is arbitrary. A very simple relation also holds for limiting activity coefficients of substances forming homologous series in two arbitrary solvents. The practical utility and accuracy of the relations obtained is demonstrated on a number of examples. The agreement with experimental data is excellent for absolute majority of the systems tested.
Glass transition temperature of hydrated mixtures of calcium chloride and nitrate, calcium bromide and nitrate, and calcium iodide and nitrate
Authors: Malá Jarmila , Sláma Ivo
Published: October 2011

The glass transition temperature depends linearly on the concentration and mole fraction of halide ions, yX, in the studied concentration range up to yX = 0.95. The behaviour of the three studied systems was compared.
Unsteady internal diffusion in dispersions
Authors: Wein Ondřej
Published: October 2011

The two parameter functional model of mass transfer is formulated between the dispersed and continuous phases without chemical reaction taking place in the dispersion and with negligible diffusion resistances in the continuous phase. The model takes into consideration polydispersity of the system and non-linearity of the equilibrium relation. The parameters of the model can be either estimated on basis of the theory of unsteady diffusion in solid particles or determined experimentally.
Extraction of americium with benzyldimethyllaurylammonium nitrate from aqueous nitrate solutions
Authors: Jedináková Věra , Cibulková Jana , Kuča Libor
Published: October 2011

The extraction of Am(III) with benzyldimethyllaurylammonium nitrate from acidic nitrate solutions was studied. The effects of the kind and concentration of the salting-out agent, of the organic solvents, and of the concentrations of the other components in the extraction system on the distribution ratio values and applicability of this extracting agent to the separation of americium from lanthanoids are discussed. From the analytical data on the organic phase and from the infrared spectra, the composition of the extractable associates and their extraction mechanism were established.
Mass spectrometric study of allyl radical, allyl bromide and 1,5-hexadiene interactions with oxides; Cobalt suboxide Co3O4
Authors: Nováková Jana , Dolejšek Zdeněk
Published: October 2011

Products of (a) allyl radical interaction with unheated Co3O4, (b) thermally activated 1,5-hexadiene or thermally activated allyl bromide with unheated Co3O4, (c) moderately heated Co3O4 with unheated 1,5-hexadiene or allyl bromide were studied under Knudsen flow conditions. Cobalt suboxide Co3O4, a typical catalyst of deep oxidations yielded acrolein in reaction with allyl radicals as early as at the room temperature of the catalyst. A similar acrolein formation was also observed in the allyl radical interaction with other oxides exhibiting different catalytic properties. It appears that acrolein is in general the primary product of the allyl radical interaction with the oxides. The results are discussed and compared with previous data obtained with MoO3.
Extension of the turbidity ratio method to the near infrared region
Authors: Sedláček Blahoslav
Published: October 2011

The turbidity ratio method has been extended to the near infrared region. In addition to the usual wavelengths 435.8, 546.1 and 684.3 nm, wavelengths 857.5, 1 074 and 1 346 nm were also used in the measurements. Using a model system of polystyrene latex, it was shown that the turbidity ratio method could be utilized also in this range of wavelengths. Its advantages and shortcomings were demonstrated.
Reaction of some 3-(phenylthioaryl)propionic acids with polyphosphoric acid; Formation of 2H-cyclopenta[k,l]thioxanthenes
Authors: Jílek Jiří O. , Holubek Jiří , Svátek Emil , Ryska Miroslav , Pomykáček Josef , Protiva Miroslav
Published: October 2011

The cyclization of 3-[2-(phenylthio)phenyl]propionic acid (I) with polyphosphoric acid gave equal amounts of 4-(phenylthio)indanone (III) and 2H-cyclopenta[k,l]thioxanthene (VI), accompanied with a small amount of the macrocyclic diketone V. Compound VI was evidently formed via the cation XII and 7-(phenylthio)indanone (X) which was quantitatively dehydrocyclized. Similar cyclization of the isomeric acid XIIIa yielded 5-(phenylthio)indanone (XVIII) as the main product; formation of VI could be detected only chromatographicaly. Cyclization of 3-[2-(chloro-5-(phenylthio)phenyl]propionic acid (XIIIb) gave 3-chloro-2H-cyclopenta[k,l]thioxanthene (VII) as the predominant product. From the by-products formed, only 4-chloro-7-(phenylthio)indanone (XI) could be identified, being the precursor of compound VII. Treatment of thioxanthene-9-acetic acid (XXII) with polyphosphoric acid resulted in a cleavage with thioxanthone (XXIII) and thioxanthene (XXIV) as the main products.
Model experiments in the synthetic approach to strophanthidin: The synthesis of 3β,5-dihydroxy-5β-cholestan-19-al
Authors: Kočovský Pavel
Published: October 2011

A five step synthesis of the title compound XV as a model substance for simple construction of the A/B ring part of strophantidin (I) is described. The key step of this synthetic approach is the hypobromous acid addition to the formate V which gives predominantly the diequatorial bromohydrin X as a result of 6(O)π,n participation of the 19-ester group in 5α,6α-bromonium ion VII cleavage. Treatment of X with Raney-Ni yields the 19-hydroxy derivative XII which on oxidation and hydrolysis gives the aldehyde XV.
Identification of impurities in benzyl butyl phthalate by gas-liquid chromatography and mass spectrometry
Authors: Novrocík Jan , Novosadová Marta
Published: October 2011

The impurities present in benzyl butyl phthalate of Monsanto, Belgium, and in benzyl butyl phthalate prepared by a modified procedure employing gaseous ammonia instead of triethylamine were identified by GLC-MS. Columns appropriate for the GLC analysis of this plasticizer were selected and their advantages and disadvantages discussed, and the optimum conditions for complete, rapid routine analysis of benzyl butyl phthalate were established. The side reactions proceeding during the preparation of benzyl butyl phthalate are discussed based on the identification of the impurities present.
13C NMR spectra of hydroxy adamantanes additivity in 13C NMR spectra of dihydroxyadamantanes
Authors: Schraml Jan , Jancke Harald , Engelhardt Günter , Vodička Luděk , Hlavatý Josef
Published: October 2011

The 13C NMR spectra of all monohydroxy and ditopic dihydroxy adamantane isomers were measured and the lines assigned. The numbers of the isomers and of the non-equivalent carbon atoms permitted a verification of the simple additivity of the shielding contributions of two hydroxyl groups on the rigid adamantane skeleton in the isomers without a possibility of a direct OH-OH interaction. If such interactions occur, deviations are found. The direction and magnitude of the deviations is in agreement with the current interpretation of 13C chemical shifts in other classes of cyclic compounds. It is concluded that the deviations are not caused by intramolecular hydrogen bonds. The deviations and the values of substituent chemical shifts offer some limited information about the origin of the shielding effects, especially of those dependent on stereochemistry and degree of substitution (γanti effect).
A contribution to the simultaneous chemical and phase equilibrium calculation
Authors: Coufal Oldřich , Fidler Alois
Published: October 2011

Some problems are treated in detail which are encountered during calculating the equilibrium composition in heterogeneous reacting systems with respect to the minimum of the total Gibbs free energy.
Adsorption of thiourea on mercury/dimethyl sulfoxide interface
Authors: Ivanova Rimma V. , Trnková Libuše , Damaskin Boris B.
Published: October 2011

Adsorption of thiourea on mercury in the medium of 0.1M KClO4 in dimethyl sulfoxide was studied by measuring the dependence of the differential capacity on the potential. The parameters of the electric double layer were evaluated and the orientation of the solvent molecules on the electrode surface was discussed in terms of certain model concepts.
Liquid phase adsorption of organic amines on sulphonated styrene-divinylbenzene copolymers
Authors: Maternová Jindřiška , Setínek Karel
Published: October 2011

Sorption of organic amines from various solvents on standard and macroporous sulphonated styrene-divinylbenzene copolymers has been studied. The amount sorbed depends above all on the molecular mass (size) of sorbate, but its chemical affinity (basicity) toward polymer functional groups plays a role, too. The solvent and copolymer crosslinking effects are in mutual relation and are less pronounced. In addition to the interaction of the sorbate with sulphonic acid groups of the polymer, the sorbate dissolves also in the polymer.
Radical cyclisation reactions of ketones with alkenes initiated by silver(II) and lead(IV) oxides
Authors: Hájek Milan , Šilhavý Přemysl , Málek Jaroslav
Published: October 2011

Acetone and 2,4-pentanedione react with α-methylstyrene in the presence of the title oxides to form 2,5-dimethyl-5-phenyl-4,5-dihydrofuran and its 3-acetyl derivative, respectively, in about 70% yields. The reaction of these ketones with styrene, which is more prone to telomerisation and polymerisation reactions, gives the corresponding 5-phenylsubstituted 4,5-dihydrofuran derivatives in lower yields (30-40%). Cyclization reaction of acetophenone with 1-octene induced by silver(II) oxide produces 4-n-hexyl-α-tetralone and decanophenone in a 70 : 30 ratio.
Kinetics and mechanism of alkaline hydrolysis of (Z)-O-(N-4-nitrophenylcarbamoyl)benzaldoximes in 30% aqueous ethanol
Authors: Mindl Jaromír , Radonský František , Klicnar Jiří , Večeřa Miroslav
Published: October 2011

Alkaline hydrolysis of (Z)-O-(N-4-nitrophenylcarbamoyl)benzaldoximes (I), the configuration of which was verified by IR spectra, produces a mixture of Z and E-benzaldoximates II and III, benzonitrile IV, and 4-nitrophenylcarbamate ion (V). In subsequent reactions II and III are hydrolyzed to benzaldehyde VI, and III and IV give finally benzoate VII. The carbamate V is decarboxylated to 4-nitroaniline (VIII). The compound I is hydrolyzed to oxime and 4-nitroaniline (VIII) in neutral medium. The hydrolysis rates of three compounds type I have been measured in 30% aqueous ethanol at pH 4 to 14. Character of the hydrolysis course in alkaline medium corresponds to a reaction of E1cB type. In neutral medium spontaneous hydrolysis with water takes place and the reaction rate is independent of concentration of hydrogen ion.
Kinetics of nucleophilic displacement of 2,5-disubstituted furans
Authors: Knoppová Viera , Kada Rudolf , Kováč Jaroslav
Published: October 2011

5-Nitro- and 5-bromo-2-furfurylidenemalonitriles react with secondary saturated amines in an SN reaction to replace bromo or nitro groups. The effects of nucleophilic reagent, solvent and temperature on the reaction rate were investigated. The results were contrasted with kinetic data of the SN reaction of 5-(4-X-phenylsulfonyl- or phenylthio)-2-furfurylidenemalonitriles.
Reaction of ketenimines with azoimide
Authors: Světlík Jan , Martvoň Augustin
Published: October 2011

Diphenyl ketene N-aryl- or N-alkylimines react with NH3 to give 1 : 1 adducts on the C=N bond of the cumulene system. Spectral properties of thus prepared 1-aryl- or 1-alkyl-5-diphenylmethyltetrazoles are discussed.
[1-β-Mercaptopropionic acid, 8-α-amino-β-guanidinopropionic acid]vasopressin and [1-β-mercaptopropionic acid, 8-D-α-amino-β-guanidinopropionic acid]vasopressin; Analogs showing a high and specific antidiuretic effect
Authors: Zaoral Milan , Krchňák Viktor , Brtník František , Machová Alena , Škopková Jana
Published: October 2011

β-Benzylthiopropionyl-tyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteine azide was condensed with prolyl-α-amino-nitroguanidinopropionyl-glycine amides (L2; D2) to β-benzylthiopropionyl-tyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteinyl-prolyl-α-amino-β-nitroguanidinopropionyl-glycine amides (L8; D8) which after removal of the protecting groups in liquid hydrogen fluoride, closure of the disulfide ring, desalting, and electrophoretic purification afforded [1-β-mercaptopropionic acid, 8-α-amino-β-guanidinopropionic acid]vasopressin (I) and [1-β-mercaptopropionic acid, 8-D-α-amino-β-guanidinopropionic acid]vasopressin (II). The antidiuretic effect of I (II) is about 10% of the effect of [1-β-mercaptopropionic acid, 8-D-arginine]vasopressin (DDAVP) (87 ± 8% DDAVP), the pressor effect is 49.5 I.U./mg (2.7 I.U./mg).
Stability constants of phosphineacetate complexes of divalent metals
Authors: Podlahová Jana
Published: October 2011

Anions of the phosphineacetic acids of the general formula (C6H5)3-nP(CH2COOH)n (n = 1-3) form with the cations Mn2+, Co2+, Zn2+, Cd2+, and Pb2+ in aqueous solutions complexes with the ratio M : L = 1 : 1 and in some cases also 1 : 2. In addition, the ligand with n = 3 exhibits the formation of the protonized complexes MHL. The stability constants of the complexes were calculated by statistical processing of the pH-metric titration curves, and the ligands were found to act as the O-donors to Mn2+ and Zn2+, and as PO (n = 1) and POO (n = 2, 3) donors to the other cations.
Synthesis and some biological properties of amides derived from [4-glutamic acid]deamino-1-carba-oxytocin
Authors: Lebl Michal , Dimeli Anastasia , Bojanovska Vera , Slaninová Jiřina , Barth Tomislav , Jošt Karel
Published: October 2011

A number of amides of [4-glutamic acid]deamino-1-carba-oxytocin, as well as certain derivatives of amino acids, and a protected hydrazide of the above-mentioned peptide were prepared by a reaction with the amino-component, using dicyclohexylcarbodiimide and 1-hydroxybenzotriazole. The analogues were checked for uterotonic and galactogogic activity.
On the conformational structure of nicotinamide and methyl-1,4-dihydronicotinamide
Authors: Hofmann Hans-Jörg , Kuthan Josef
Published: October 2011

The conformation of nicotinamide (I) and 1-methyl-1,4-dihydronicotinamide (II) was examined using the NDDO method. The influence of solvent on the molecular structure of the title compounds was estimated by means of a continuum model. Analysis of the NDDO wave functions contributes to the knowledge about the mechanism of the NADH reduction.
Inhibition by dihydrorifampicin of RNA polymerases I and II isolated from nuclei of Rous sarcoma cells and human tumor cells HEp-2
Authors: Kára Jindřich , Hostomský Zdeněk
Published: October 2011

Dihydrorifampicin, a rifampicin derivative hydrogenated at the 18-19 carbon atoms of the aliphatic ansa chain of the rifampicin molecule, inhibits the enzymatic activity of RNA polymerases I and II, isolated from the nuclei of avian tumor cells (Rous sarcoma) and from the human tumor cell line HEp-2. The RNA polymerases from these tumors have been separated and partially purified by chromatography on DEAE Sephadex A-25 and characterized by the sensitivity to α-amanitin. The [3H]UMP-labeled ribonucleic acids synthesized in the isolated nuclei of Rous sarcoma cells in the presence and absence of DHR were analyzed by sedimentation analysis in sucrose density gradients. It was found that the synthesis of rRNAs and mRNAs is very significantly inhibited by dihydrorifampicin, whereas the synthesis of tRNAs is much less inhibited at the same DHR concentration (100μg/ml). The observed cytostatic effect of DHR on the growth of human tumor cells HEp-2 and embryonic cells in culture is apparently mediated by the selective inhibition of RNA polymerases I and II in human and avian cells. The relationship between the molecular structure of DHR and its affinity to RNA polymerases of eukaryotic cells is discussed.
Mass transfer in the system with instantaneous chemical reaction and interfacial turbulence extraction of acetic acid from isobutanol into aqueous solution of sodium hydroxide
Authors: Řeháková Milada , Rod Vladimír
Published: October 2011

Extraction of acetic acid from isobutanol into aqueous solution of sodium hydroxide in the system with flat interface was studied. The effect of interfacial turbulence, induced by chemical reaction on the mass transfer rate of reacting components across the interface was determined independently from measurements of mass transfer rate of non-reacting solvents. The concept of enhancement factor was used for description of the phenomenon. The effect of interfacial turbulence on mass transfer rate was expressed by the additive term to the rate of energy dissipation on the interface.
Electrostatic effects on ionization equilibria. 3-Substituted bicyclo[2,2,2]octane-1-carboxylic acids
Authors: Friedl Zdeněk , Hapala Jaroslav , Exner Otto
Published: October 2011

Nine 3-substituted (I-IX) and one 2-substituted (XI) bicyclo[2,2,2]octane-1-carboxylic acids were prepared as model compounds for verification of the electrostatic theory of substituent effects. On the one hand they are regular-shaped and suitable for calculations, on the other hand they allow to evaluate the role of the angle θ of the substituent dipole. The apparent pK values in 50% ethanol and 80% methyl cellosolve were correlated with σI constants (ρI 1.18 and 1.42, respectively) and compared with theoretical predictions based on the spherical and ellipsoidal cavity models. The agreement is very good with the new Ehrenson model but still satisfactory with some others not matching exactly the actual molecule shape. The substituent effects are resonably correlated with the substituent dipoles and with the geometrical parameters but exceptions are notable. Comparison with the previous results implies that the theory reproduces fairly the substituent effects in carboxylic acids of a given molecular size and not too unsymmetrical shape; the cavity model is, however, sufficiently flexible to compensate partly even for some non-electrostatic effects neglected by the basic theory.
Potential metabolites of tricyclic neuroleptics: 2,8-Dihydroxy and 3,8-dihydroxy derivatives of 10-(4-methylpiperazino)-10,11-dihydrodibenzo[b,f]thiepin
Authors: Protiva Miroslav , Šindelář Karel , Šedivý Zdeněk , Pomykáček Josef
Published: October 2011

A synthesis of the title compounds II and III, potential metabolites of the neuroleptic agent perathiepin I, was carried out. A reaction of (2-iodo-5-methoxyphenyl)acetic acid with 4-methoxythiophenol afforded the acid VI. The isomeric acid XI was obtained from 2-iodo-4-methoxybenzoic acid by reaction with 4-methoxythiophenol and via intermediates VIII-X. Both acids (VI,XI) were cyclized with polyphosphoric acid to dimethoxydibenzo[b,f]thiepin-10(11H)-onesXIIab which were transformed via the alcohols XIIIab to the chloro compounds XIVab. Substitution reactions with 1-methylpiperazine gave the piperazine derivatives IV and V and dimethoxydibenzo[b,f]thiepins XVab. The dimethoxy compounds IV and V were demethylated with boron tribromide to the diaminodiphenols II and III. The central depressant and cataleptic activity of compounds II-V is lower than that of the unsubstituted substance I.
Isolation and sequential studies of peptides from tryptic digest of trichloroacetic acid precipitate of partly autolyzed alkaline protease from Aspergillus flavus
Authors: Mikeš Otakar , Toan Nguyen bao , Turková Jaroslava
Published: October 2011

A partly autolyzed preparation of the alkaline protease from As. flavus, denatured by trichloroacetic acid, was resolved into the high and low molecular weight part; the amino acid composition of both parts was similar to that of the native protease. The high molecular weight part was subjected to tryptic digestion; the digest was fractionated by chromatography on a sulfonated ion exchange resin and by paper electrophoresis and paper chromatography techniques. The peptides isolated were characterized by amino acid analysis and terminal end group analysis. Peptides obtained in larger quantities were sequenced. The data on peptides obtained in this study are compared with the results of earlier work on nonradioactive peptides from a partial hydrolysate of the [32P]DIP-labeled enzyme.
Activation of latent collagenase from polymorphonuclear leukocytes by cathepsin G
Authors: Stančíková Mária , Trnavský Karel
Published: October 2011

Cathepsin G was isolated from human polymorphonuclear leukocytes and purified by affinity chromatography on Antilysin-Sepharose column. Purified enzyme activated later collagenase isolated from leukocytes. Activation at 36°C was maximal after 30 min incubation. Inhibitors of cathepsin G - soya-bean trypsin inhibitor, diisopropyl phosphofluoridate and Antilysin were active in inhibiting the activation of latent collagenase by cathepsin G.
Composition of the wax of Sonchus asper VILL.
Authors: Behari Mukat , Gupta Rajiv , Streibl Milan
Published: October 2011

Chromatographic and spectroscopic methods were employed for analysis of the plant wax of Sonchus asper VILL. The wax contains hydrocarbons (11.7%), esters (17.4%), triterpene acetates (16.1%), primary alcohols (11.1%), triterpenic alcohols (7.8%) and sterols (11.7%).
Immobilization of trypsin on periodate-oxidized glucosehydroxyalkyl methacrylate gel Separon-H 1 000-glc
Authors: Vančurová Drahomíra , Turková Jaroslava , Čoupek Jiří , Frydrychová Anna
Published: October 2011

The dependence of the amount of bound enzyme on the oxidation time, molarity of the oxidizing solution, pH, time, temperature and enzyme concentration in the reaction mixture were investigated for the case where trypsin is covalently bound on the hydroxyalkyl methacrylate gel containing glucose on its surface (Separon-H 1 000-glc) after the gel had been periodate-oxidized. The immobilized derivatives of trypsin were examined with respect to their catalytic activity and stability in continuous hydrolysis.
The role of conformational mobility in the stereospecific loss of water under electron impact
Authors: Tureček František , Hanuš Vladimír , Tichý Miloš
Published: October 2011

Mass spectra of nine of the sixteen possible diastereoisomeric 7-hydroxytricyclo[7.3.0.02,6]dodecanes are reported. The spectra differ considerably in the extent of water elimination from molecular ions. The diastereoisomers which have conformationally flexible cis-anti-cis, cis-anti-trans and cis-syn-trans skeletons exhibit abundant (M-H2O)+. ions. Molecular ions of the rigid trans-anti-trans isomers lose water to a markedly smaller extent, the main fragmentation proceeding via a skeletal cleavage. Effects of conformational mobility are emphasized.
Potential metabolites of the neuroleptic agents noroxyclothepin and oxyclothepin; Synthesis of 8-chloro-3-hydroxy-10-[4-(2-hydroxyethyl)piperazino]- and -10-[4-(3-hydroxypropyl)piperazino]-10,11-dihydrodibenzo[b,f]thiepin
Authors: Šindelář Karel , Holubek Jiří , Svátek Emil , Ryska Miroslav , Metyšová Jiřina , Šedivý Zdeněk , Protiva Miroslav
Published: October 2011

Substitution reactions of 8,10-dichloro-3-methoxy-10,11-dihydrodibenzo[b,f]thiepin with 1-(2-hydroxyethyl)piperazine and 1-(3-hydroxypropyl)piperazine gave the piperazine derivatives IX andX; their demethylation with boron tribromide led to unfavourable results. New procedure for the synthesis of phenolic amines was elaborated starting with demethylation of 8-chloro-3-methoxydibenzo[b,f]thiepin-10(11H)-one with pyridine hydrochloride, followed by reduction of the hydroxyketone XIII to the diol XIV. Reaction with methanesulfonyl chloride in the presence of triethylamine resulted in the dimethanesulfonic ester XV which was treated with 1-(2-hydroxyethyl)piperazine and 1-(3-hydroxypropyl)piperazine. The aliphatic sulfoester group underwent substitution, confirmed by isolation of compound XII. The aminolysis afforded phenolic compounds VII and VIII being potential metabolites of the neuroleptic agents noroxyclothepin (III) and oxyclothepin (IV). Both phenolic amino alcohols have only very low central depressant and cataleptic activity.
Ion selective picrate electrode with liquid membrane
Authors: Homolka Daniel
Published: October 2011

An ion selective picrate electrode with a liquid membrane supported by a poly(vinyl chloride) matrix was proposed. Cetyltrimethylammonium cations in n-hexyl-o-nitrophenyl ether serve as an ion exchanger. The electrode is suitable for analytical purposes.
Aminomethylation of BINOL with methyleneiminium salts
Authors: Shustov Gennady , Khlebnikov Vladimir
Published: October 2011

A new method for synthesizing chiral 3,3′-bis(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols with high enantiomeric excess is described. The procedure consists of bis-lithiation of diprotected (S)- or (R)-1,1′-bis(2-naphthol) followed by treatment of the intermediate with methyleneiminium salts. Mild reaction conditions prevent racemization and provide 3,3′-bis(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols or 3-(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols with an enantiomeric excess >99%.
Feasibility study of hydrogen-bonded nucleic acid base pairs in gas and water phases — A theoretical study
Authors: Arshadi S. , Bekhradnia A.R. , Ebrahimnejad A.
Published: October 2011

To investigate the base pair binding probabilities for nucleic acid bases, numerous models were studied for contacts between adenine, thymine, guanine, cytosine, and uracil using density functional theory (DFT) in combination with the 6–311G* basis set. We obtained an assessment for the energy given by our calculations in gas and aqueous phases, which showed that it should be incorporated into hydrogen bonding and propeller rotational energies. The 42 complexes of base pairs (5 regular and 37 irregular base pairs) were proposed and their hydrogen-bonding (H-bonding) properties were verified. The hydrogen bonds in some irregular base pairs, including CC, UU, and TT (series 1), were stronger than in regular GC and AT base pairs. Also, the strength of the hydrogen bonds in the proposed base pairs, including CU, GG, GU, and TU (series 2), were similar to regular base pairs from an energetic point of view. The propeller rotations revealed a higher rotational barrier energy (6–7.5 kcal/mol; 1 cal = 4.184 J) for irregular base pairs (series 1 and 2) than regular GC and AT ones (1–3 kcal/mol). Nevertheless, the trend in these affinities of the complex contact probabilities and their biological properties were confirmed by our calculations.
The Price of Anonymity
Authors: Bonnet François , Raynal Michel
Published: October 2011

This article addresses the consensus problem in asynchronous systems prone to process crashes, where additionally the processes are anonymous (they cannot be distinguished one from the other: they have no name and execute the same code). To circumvent the three computational adversaries (asynchrony, failures, and anonymity) each process is provided with a failure detector of a class denoted
ψ
, that gives it an upper bound on the number of processes that are currently alive (in a nonanonymous system, the classes
ψ
and
P
---the class of perfect failure detectors---are equivalent).

The article first presents a simple
ψ
-based consensus algorithm where the processes decide in 2
t
+ 1 asynchronous rounds (where
t
is an upper bound on the number of faulty processes). It then shows one of its main results, namely 2
t
+ 1 is a lower bound for consensus in the anonymous systems equipped with
ψ
. The second contribution addresses early-decision. The article presents and proves correct an early-deciding algorithm where the processes decide in min(2
f
+ 2, 2
t
+ 1) asynchronous rounds (where
f
is the actual number of process failures). This leads us to think that anonymity doubles the cost (with respect to synchronous systems) and it is conjectured that min(2
f
+ 2, 2
t
+ 1) is the corresponding lower bound.

The article finally considers the
k
-set agreement problem in anonymous systems. It first shows that the previous
ψ
-based consensus algorithm solves the
k
-set agreement problem in
Rt
= 2⌊t k⌋ + 1 asynchronous rounds. Then, considering a family of failure detector classes {
ψℓ
}0 ≤
ℓ
<
k
that generalizes the class
ψ
(=
ψ
0
), the article presents an algorithm that solves the
k
-set agreement in
Rt,ℓ
= 2 ⌊
t k − ℓ
⌋ + 1 asynchronous rounds. This last formula relates the cost (
Rt,ℓ
) the coordination degree of the problem (
k
), the maximum number of failures (
t
), and the the strength (
ℓ
) of the underlying failure detector. Finally the article concludes by presenting problems that remain open.
SREBP-1 activation by glucose mediates TGF-β upregulation in mesangial cells
Authors: Uttarwar Lalita , Gao Bo , Ingram Alistair J. , Krepinsky Joan C.
Published: October 2011

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. Recent studies showed that overexpression of the transcription factor sterol-responsive element-binding protein (SREBP)-1 induces pathology reminiscent of diabetic nephropathy, and SREBP-1 upregulation was observed in diabetic kidneys. We thus studied whether SREBP-1 is activated by high glucose (HG) and mediates its profibrogenic responses. In primary rat mesangial cells, HG activated SREBP-1 by 30 min, seen by the appearance of its cleaved nuclear form (nSREBP-1), EMSA, and by activation of an SREBP-1 response element (SRE)-driven green fluorescent protein construct. Activation was dose dependent and not induced by an osmotic control. Site 1 protease was required, since its inhibition by AEBSF prevented SREBP-1 activation. SCAP, the ER-associated chaperone for SREBP-1, was also necessary since its inhibitor fatostatin also blocked SREBP-1 activation. Signaling through the EGFR/phosphatidylinositol 3-kinase (PI3K) pathway, which we previously showed mediates HG-induced TGF-β1 upregulation, and through RhoA, were upstream of SREBP-1 activation (Wu D, Peng F, Zhang B, Ingram AJ, Gao B, Krepinsky JC. Diabetologia 50: 2008–2018, 2007; Wu D, Peng F, Zhang B, Ingram AJ, Kelly DJ, Gilbert RE, Gao B, Krepinsky JC. J Am Soc Nephrol 20: 554–566, 2009). Fatostatin and AEBSF prevented HG-induced TGF-β1 upregulation by Northern blot analysis, and HG-induced TGF-β1 promoter activation was inhibited by both fatostatin and dominant negative SREBP-1a. Chromatin immunoprecipitation analysis confirmed that HG led to SREBP-1 binding to the TGF-β1 promoter in a region containing a putative SREBP-1 binding site (SRE). Thus HG-induced SREBP-1 activation requires EGFR/PI3K/RhoA signaling and SCAP-mediated transport to the Golgi for its proteolytic cleavage. Activated SREBP-1 binds to the TGF-β promoter, resulting in TGF-β1 upregulation in response to HG. SREBP-1 thus provides a potential novel therapeutic target for the treatment of diabetic nephropathy.
Analysis of Model Parameters for a Polymer Filtration Simulator
Authors: Brackett-Rozinsky N. , Mondal S. , Fowler K. R. , Jenkins E. W.
Published: October 2011

We examine a simulation model for polymer extrusion filters and determine its sensitivity to filter parameters. The simulator is a three‐dimensional, time‐dependent discretization of a coupled system of nonlinear partial differential equations used to model fluid flow and debris transport, along with statistical relationships that define debris distributions and retention probabilities. The flow of polymer fluid, and suspended debris particles, is tracked to determine how well a filter performs and how long it operates before clogging. A filter may have multiple layers, characterized by thickness, porosity, and average pore diameter. In this work, the thickness of each layer is fixed, while the porosities and pore diameters vary for a two‐layer and three‐layer study. The effects of porosity and average pore diameter on the measures of filter quality are calculated. For the three layer model, these effects are tested for statistical significance using analysis of variance. Furthermore, the effects of each pair of interacting parameters are considered. This allows the detection of complexity, where in changing two aspects of a filter together may generate results substantially different from what occurs when those same aspects change separately. The principal findings indicate that the first layer of a filter is the most important.
Tight Representations of 0‐E‐Unitary Inverse Semigroups
Authors: Tabatabaie Shourijeh Bahman , Jokar Asghar
Published: October 2011

We study the tight representation of
a semilattice in {0, 1} by some examples. Then we introduce the
concept of the complex tight representation of an inverse semigroup
S by the concept of the tight representation of the semilattice of
idempotents E of S in {0, 1}. Specifically we describe the tight
representation of a 0‐E‐unitary inverse semigroup and prove that
if σ is a tight semilattice representation of the 0‐E‐unitary inverse
semigroup S in {0, 1}, then σ is a complex tight representation.
HER-2 Evaluation in a Specific Gastric Cancer Population with the Highest Rate of Mortality in Spain
Authors: Cidon E. U. , Centeno R. G. , Lagarto E. G. , Peral J. I.
Published: October 2011

Gastric cancer (GC) still represents the second cause of cancer-related death worldwide. Radical resection is the mainstay of early stages treatment with little impact on overall survival (OS) in the advanced ones. HER-2 is the most relevant biological factor involved.Purpose. This study aims to show the relationship between HER-2 positivity and survival in patients with completely resected GC.Methods. Retrospective study of GC patients diagnosed in 2003–2005 at our institution. Surgical specimens underwent immunohistochemistry (IHC), and in cases +/++/+++ samples underwent also fluorescence in situ hybridisation (FISH) analyses of HER-2 and graduated according to experts' consensus.Results. 120 cases included. Overall expression detected in 7.5%. Correlation between HER-2 positive and female sex, advanced stages or histological grades, or intestinal type was detected. Early recurrences higher in HER-2 positive (66.6% versus 35.4%, ). The median DFS for c-erbB-2 positive was 15 months (range 2–67 months), and OS was 25 months (range 10–67 months). In the case of patients with c-erbB-2, negative median DFS was 27 months (range 5–67 months) and OS for this sample is 47 months (range 29–67 months).Conclusions. These results emphasize the relevance of HER-2 positivity in GC as independent prognostic factor and support its current analyses in daily practice.
On the Distance to a Root of Polynomials
Authors: Chaiya Somjate
Published: October 2011

In 2002, Dierk Schleicher gave an explicit estimate of an upper bound for the number of iterations of Newton′s method it takes to find all roots of polynomials with prescribed precision. In this paper, we provide a method to improve the upper bound given by D. Schleicher. We give here an iterative method for finding an upper bound for the distance between a fixed point z in an immediate basin of a root α to α, which leads to a better upper bound for the number of iterations of Newton′s method.
In Search of a Vaccine for Mouse Allergy: Significant Reduction of Mus m 1 Allergenicity by Structure-Guided Single-Point Mutations
Authors: Ferrari Elena , Breda Daniela , Longhi Renato , Vangelista Luca , Nakaie Clóvis R. , Elviri Lisa , Casali Emanuela , Pertinhez Thelma A. , Spisni Alberto , Burastero Samuele E.
Published: October 2011

Background: Mouse urinary proteins are relevant allergens from mice urine. We used the recombinant protein Mus m 1 as an allergen model to identify if, by altering Mus m 1 architecture via single-point mutations, we could effectively modify its allergenicity. Methods: Based on structural considerations, we synthesized two single-point mutants, Mus m 1-Y120A and Mus m 1-Y120F, which were expected to harbor large structural alterations. Circular dichroism and fluorescence analysis showed significant conformational rearrangements of the aromatic side chains in the internal cavity of Mus m 1-Y120A when compared to Mus m 1-Y120F and Mus m 1. Evaluation of the allergenic potential of the recombinant molecules was performed in vitro with both immunochemical approaches and assays based on the measurement of basophil degranulation. Moreover, to assess the integrity of the T cell epitopes and as an in vitro measure of immunogenicity, we tested the reactivity of T lymphocytes from subjects allergic to mouse urine against proteins and synthetic peptides encompassing the immunodominant linear epitope containing the mutation. Results: We found that the selected point mutation was able to modulate the protein allergenicity, and to severely impair the recognition of Mus m 1 by IgE, while T cell reactivity was fully maintained. Conclusions: In silico predicted, minimum selected structural modifications allowed to design one protein with reduced allergenicity and preserved immunogenicity. Structurally guided mutations can direct the design of proteins with reduced allergenicity which can be used as vaccines for a safer and more effective immunotherapy of allergic disorders.