bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of pH and temperature on alcohol dehydrogenase
Authors: Leblová Sylva , Lapka Roman , Nováková Noemi
Published: October 2011

Alcohol dehydrogenase isolated from germinating pea seeds catalyzes ethanol oxidation at pH 8.7 and acetaldehyde reduction at pH 7.0. The values of the Michaelis constants are the lowest in the range of pH-optimums. The effect of temperature on the reaction rate was investigated over the range 15-55 °C. The initial and maximal rates increase with the increasing temperature and attain a maximum at 40 °C. The values of the Michaelis constants are the lowest at 21 °C. Pea alcohol dehydrogenase looses its activity at 70 °C, the binary enzyme-NAD complex is more thermostable.
Reduction of 2-, 3- and 4-acetylquinolines by triethylammonium formate
Authors: Kocián Oldřich , Ferles Miloslav
Published: October 2011

The reduction of 2-, 3- and 4-acetylquinolines (Ia-c) by triethylammonium formate affects both the pyridine part of the quinoline nucleus and the carbonyl groups, giving rise to products II-VI.
Cationic polymerization of isoprene: Initiation by complexes of titanium chloride with halogenoacetic acids
Authors: Matyska Bohumír , Petrusová Ludmila , Mach Karel , Švestka Miroslav
Published: October 2011

Polymerization of 2-methyl-1,3-butadiene (isoprene), initiated by titanium chloride in combination with trifluoro- and trichloroacetic acid and their t-butyl esters as coinitiators, was studied in benzene, 1,2-dichlorobenzene and heptane at 20 °C. Curves of the dependence polymerization rate vs coinitiator concentrations exhibit in the first two media a minimum and a maximum, those in heptane exhibit an inflex only. This is due to the fact that the acids and the esters are partly consumed to carboxylate TiCl4 and to form mono- and dicarboxylates of titanium chloride. Other products are either HCl or the corresponding alkylchlorides whose co-catalytic activity is very low. It follows from kinetic data and from electric conductivity and infrared spectra measurements that active centers in the polymerization are complexes of oligoesters of halogenoacetic acids with TiCl4 and its carboxylates, in which the ester bond is either considerably polarized or dissociated. Free ions are formed during the polymerization, too, contributing to changes of electric conductivity; however, they do not influence the polymerization rate directly.
Beckmann rearrangement of 2-oximinoadamantane in hydrobromic acid
Authors: Tříska Jan , Vodička Luděk , Hlavatý Josef
Published: October 2011

Rearrangement of 2-oximinoadamantane in hydrobromic acid and its dependence on acid concentration, temperature and reaction time was studied. The reaction affords 4-bromoadamantan-2-one, together with 4-azatricyclo[4,3,1,13,8]undecan-5-one and 4-hydroxyadamantan-2-one. This reaction can be used as a preparative method for synthesis of 4-bromoadamantan-2-one.
Synthesis of 5-nitro-2-vinylfuran by Wittig method
Authors: Végh Daniel , Kováč Jaroslav , Dandárová Miloslava
Published: October 2011

The conversion of furfuryl alcohol to 5-nitro-2-vinylfuran (VI) is described. The new method of preparation is based on the Wittig reaction carried out in aqueous formaldehyde.
Correlation of electrochemical and quantum chemical data for reduction of halogen derivatives of benzene and biphenyl
Authors: Komenda Jaro , Janderka Pavel
Published: October 2011

Electrochemical splitting of the sp2 hybrid carbon-halogen bond was chosen as a typical example of an irreversible electrode reaction. It was shown in the series of chloro derivatives of benzene and biphenyl and bromo derivatives of benzene that the correlation of the electrochemical reduction potentials with the energies of the lowest unoccupied π-orbital are in these cases not physically grounded, whereas correlations with quantum-chemical parameters characterizing the carbon-halogen bond turned out to be real. Most suitable is the correlation with Wheland's localization energies calculated with the assumption of separating the carbon-halogen group from the total delocalized π-electron system in forming the transition state.
Cationic polymerization of 1-chloro-2,3-epoxypropane initiated by triphenylmethylhexafluoroantimonate(V)
Authors: Antropiusová Helena , Poláček Jindřich
Published: October 2011

The activity of Ph3CZXn in the initiation of polymerization of 1-chloro-2,3-epoxypropane decreases in dependence on ZXn in the following series AsF6(-) ≥ SbF6(-) ##i SbCl6(-) > AlCl4(-) > SnCl5(-) > TiCl5(-). The polymerization initiated by Ph3CSbF6 is a first-order reaction both with respect to the monomer and to the catalyst. The following values were determined for the rate constants of initiation, propagation, and termination, respectively: ki = 3 . 10-6 mol-1 l s-1; kp = 9 . 10-2 mol-1 l s-1; kt = 2 . 10-4 mol-1 l s-1. The initiation occurs via a hydride-ion transfer from 1-chloro-2,3-epoxypropane to the triphenylmethyl cation. The oxonium ion formed by Ph3C(+) addition on 1-chloro-2,3-epoxypropane presumably does not take part in the initiation; the equilibrium constant of formation of this adduct Ke is 3.0 . 10-1 mol-1 l. Oligomers are n-multiples of monomeric epichlorohydrine, and products of Pn 4-7 have mostly cyclic structure.
Acid-catalyzed migration of N4-acyl groups in cytosine derivatives
Authors: Holý Antonín
Published: October 2011

Heating 1-(2,3-di-O-benzoyl-β-D-arabinofuranosyl)-N4-benzoylcytosine (I) in 80% acetic acid afforded 1-(2,3-di-O-benzoyl-β-D-arabinofuranosyl)-N3-benzoylcytosine (II). Benzoylation of 5'-O-tritylcytidine (V) led to the 2',3',N4-tribenzoyl derivative VI which was refluxed with 80% acetic acid to give 2',3',N3-tribenzoylcytidine (VII). Analogously, 2',3',5',N4-tetrabenzoylcytidine (IX), prepared by benzoylation of cytidine with benzoyl cyanide, gave on reflux with 80% acetic acid 2',3',5',N3-tetrabenzoylcytidine (X). Under identical conditions, 1-methyl-N4-benzoylcytosine (XI) afforded directly 1-methyluracil (XII) .This migration takes place also in acetyl derivatives of cytosine nucleosides: 2',3',5',N4-tetraacetylcytidine (XIII) was transformed to the N3-acetylcytosine derivative XIV. On the other hand, migration of acetyl or benzoyl group from the exo-amino group of adenine has not been observed under the mentioned conditions. The migration of the N4-acyl group of cytosine derivatives proceeds best in aqueous acetic acid, more slowly also in anhydrous acetic acid, but not by action of trifluoroacetic acid in 1,2-dichloroethane.
Simultaneous flow of ions and heat to a plate electrode in the region of natural convection
Authors: Novák Petr , Roušar Ivo
Published: October 2011

The Sherwood criterion was calculated for a flow of ions to the surface of a plate electrode during natural convection by solving the Navier-Stokes, convective diffusion, and convective heat transfer equations. The solution for the boundary layer region was performed by the collocation method using orthogonal exponential polynomials. Values of the Sh criterion were obtained for Sc ##m <500; 2 000>, Pr ##m <5; 20>, and GrT/GrM ##m <0.2; 8.0>. A comparison with literature data revealed the best agreement with average errors of +2.0 and -1.4%. Another equation with an error of only +0.5% is proposed.
Porous copolymers of methacrylic acid with N-(2-hydroxypropyl) methacrylamide and (2-hydroxyethyl) methacrylate. Preparation, swelling and morphology
Authors: Vacík Jiří , Pelzbauer Zdeněk , Kuznetsova Nadezhda N. , Papukova Klavdia P. , Shataeva Larisa K. , Samsonov Georgii V. , Kálal Jaroslav , Kopeček Jindřich
Published: October 2011

Porous copolymers of methacrylic acid with N-(2-hydroxypropyl) methacrylamide or (2-hydroxyethyl) methacrylate were prepared using 1,3,5-triacryloylhexahydrotriazine as the crosslinking agent. The copolymers were characterized by their swelling, bulk weight, and morphologically by scanning electron microscopy. Data thus obtained were used in the interpretation of the formation of different porous morphology, differing in the size and ordering of globules.
The 1H NMR spectra and the conformation of 1,6-anhydro-β-D-hexopyranoses and their triacetates
Authors: Buděšínský Miloš , Trnka Tomáš , Černý Miloslav
Published: October 2011

The 1H NMR spectra of 1,6-anhydro-β-D-hexopyranoses and their triacetates, measured in hexadeuteriodimethyl sulfoxide or deuteriochloroform, confirmed the existence of these compounds in 1C4(D) conformations, with the pyranose ring partly planarized in dependence on the configuration of the substituents in positions C(2), C(3) and C(4). The effects of the substituents on the chemical shifts and the adjusted relationship for the dependence of vicinal coupling constants on the torsion angle are discussed in detail from the point of view of the determination of the configuration and the conformation of 1,6-anhydro-β-D-hexopyranoses and their derivatives. The 1H NMR spectra of triacetates were also measured in the presence of the lanthanide shift reagent, tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione) europium (III) [Eu.(FOD)3].
Reaction of 5-nitrofurfuryltrichloromethyl sulfone with aliphatic aldehydes. The synthesis of cyclopropanes derived from 5-nitrofuran
Authors: Geisbacher Daniel , Jurášek Adolf , Kováč Jaroslav
Published: October 2011

5-Nitrofurfuryltrichloromethyl sulfone (I) reacts with aliphatic aldehydes under catalysis of piperidine in dioxane at 80-100 °C to give 1-(5-nitro-2-furyl)-1-trichloromethylsulfonyl-2-(5-nitro-2-furyl)-3-R-cyclopropanes (R = H, CH3, C2H5 and C3H7). 1-(5-Nitro-2-furyl)-1-trichloromethylsulfonyl-2-methylethylene (II) was synthesized by condensation of I with ethanal. The mechanism of formation of cyclopropanes is suggested and the effect of the bulkiness of substituents on the stereospecificity leading to final products is discussed. The spectra (1H NMR, IR, UV and mass) of cyclopropanes III-VI are interpreted.
Comments on the concentration-dependence of the viscosity of solutions of discrete particles in a homogeneous continuum
Authors: Kovář Josef , Bohdanecký Miloslav
Published: October 2011

It has been demonstrated that, for systems containing discrete particles dispersed in a continuum, the mathematical relation between viscosity and concentration is the same over the whole concentration range, provided that certain conditions are fulfilled; those conditions are: a) concentration is expressed as the volume fraction of the particles in the solution; b) the particles interact only hydrodynamically. This statement is true both for monodisperse solutions, in which the absolute size of particles may vary from one solution to another and for heterodisperse solutions but in the latter case it must be stipulated that all the solutions must contain the same qualitative distribution of shapes and sizes, so that they differ from one another only in the sense that each individual particle is scaled (up or down) relatively to the corresponding particle in another solution by a factor which is constant for all the particles.
5-Nitro-2-furylvinylation of aromatic compounds
Authors: Hrabovský Ján , Kováč Jaroslav
Published: October 2011

A new synthesis of (E)-2-(4-X-phenyl)-1-(5-nitro-2-furyl)ethylenes (X = H, CH3, OH, OCH3), 2-(2-naphthyl)-1-(5-nitro-2-furyl)ethylene and 2-(2-thienyl)-1-(5-nitro-2-furyl)ethylene from (Z)-2-bromo-1-(5-nitro-2-furyl)ethylene and the respective aromatic or heteroaromatic derivative under catalysis of aluminium chloride is described.
Effect of the scintillator on the instability of determination of 32P and 3H + 32P in liquid scintillation spectrometer
Authors: Rexa Radimír , Tykva Richard
Published: October 2011

The time course of the changes of the counting rate caused by 32P is determined in six commercially available scintillation mixtures applicable to aqueous solutions of the samples. The measurements were performed separately in the 3H- and 32P-measuring channels. Statistically significant changes were found during the first day after the sample preparation for Unisolve 100, Unisolve 1, and Aquasolve in both counting channels, and for Unisolve ELS in the 3H-channel. Minisolve and Instagel exhibited steady values during 60 and 78 h, respectively, and after that period the changes proceeded very slowly. The stability of the counting rates for Minisolve and Instagel was checked also for 3H alone and for combined 3H + 32P-labelled samples.
8-Hydroxyergotamine, a new ergot alkaloid
Authors: Krajíček Alois , Trtík Bohumil , Spáčil Jiří , Sedmera Petr , Vokoun Jindřich , Řeháček Zdeněk
Published: October 2011

A new alkaloid was found in the mother liquors remaining after the isolation of ergotamine from the natural ergot. The structure of 8-hydroxyergotamine was assigned by the spectroscopic methods.
Reaktionskinetische Untersuchung und mathematische Modellierung einer Fotochlorierungsreaktion
Authors: Thiele R. , Weickert G. , Hertwig K. , Voss H.
Published: October 2011

Bei der Auswahl und Dimensionierung von fotochemischen Versuchsreaktoren sind ubersicht liche stromungs- und strahlungstechnische Bedingungen zu gewahrleisten und das Emissionsspektrum des Strahlers, das Durchlassigkeitsverhalten des Reaktormaterials und das Absorptionsspektrum des Reaktionsgemisches zu berucksichtigen. Die Untersuchung der Reaktionskinetik der Fotochlorierung von Benzol-Maleinsaureanhydrid-Mischungen erfolgt in Ruhrreaktor bei diskontinuierlicher und halbkontinuierlicher Reaktionsfuhrung mit Quecksilberhochdruckstrahlern. Das entwickelte kinetische Modell erlaubt eine Massstabsubertragung fur stark veranderte Betriebsbedingungen.
Reactions of some 2-(6-azauracil-5-yl)phenylhydrazones
Authors: Slouka Jan
Published: October 2011

Azo coupling of the diazotized 6-(2-aminophenyl)-2,3,4,5-tetrahydro-1,2,4-triazine-3,5-dione with ethyl cyanoacetylcarbamate and diethyl malonyl-bis-carbamate has been used for preparation of the hydrazones I and II. The latter substances have been boiled in strongly acidic medium to give 2,3,4,6-tetrahydro-1,2,4-triazino[5,6-c]cinnoline-3-one (III) which has also been obtained by reduction of the mentioned diazonium salt with alkali sulphite and sebsequent cyclization of the formed hydrazine sulphonate by boiling in acid medium. In alkaline medium the hydrazones I and II have been cyclized to the nitrile IV and to 2-[2-(3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazin-6-yl)-phenyl]-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-carboxylic acid (V), respectively.
Mutual relations between excess thermodynamic functions related to different reference states
Authors: Hála Eduard
Published: October 2011

General relations between excess thermodynamic functions and activity coefficients related to different standard states are derived in a thermodynamically exact way and discussed from the point of view of their chemical-engineering applications.
Texture of a limestone calcine and its reactivity with sulphur dioxide
Authors: Hartman Miloslav , Pata Jaroslav
Published: October 2011

A micro-grained limestone was used to study the effects of such variables as temperature and time of exposure to the gas on surface area, pore size distribution and porosity of calcined particles under the conditions applicable to a practical unit for fluidized-bed combustion and desulphurization. The mean pore size was correlated as a function of the temperature of calcination. An optimum temperature was found for the sulphation reaction of the carbonate.
Study of mechanism of oxidation of acrolein on a vanadium-molybdenum oxide catalyst
Authors: Popova Galya Y. , Boreskov Georgii K. , Andrushkevich Tamara V. , Tichý Josef
Published: October 2011

The mechanism of the incorporation of oxygen into the products of acrolein oxidation has been studied by a microcatalytic pulse technique with vibrating catalyst bed. It was found that acrylic acid is formed as the product of partial oxidation by stepwise redox mechanism and that in addition to the catalyst oxygen, also oxygen from the gas phase participates in carbon dioxide formation.
The synthesis and the pharmacological properties of enantiomeric derivatives of 7-(2,3-dihydroxypropyl)theophylline
Authors: Holý Antonín , Vaněček Miroslav
Published: October 2011

7-(S)-(2,3-Dihydroxypropyl)theophylline ((S)-I) and its enantiomer (R)-I were prepared by heating of the sodium salt of theophylline with 1-O-toluenesulfonyl-2,3-O-isopropylidene-D-glycerol or its L-enantiomer and subsequent acid hydrolysis. The two enantiomers I do not differ either by the inhibition of 3',5'-cAMP-phosphodiesterase, vasodilatatory activity on isolated guinea-pig aorta, or the effect on blood circulation of dogs in vivo.
The effect of preparation conditions of a platinum hydrogentaion catalyst on its activity and on the dispersity of platinum crystallites
Authors: Hanika Jiří , Sporka Karel , Růžička Vlastimil , Bauer Jaroslav
Published: October 2011

The paper deals with the preparation of a hydrogenation catalyst, 5% of platinum on active carbon. The support was saturated with aqueous chloroplatinic acid or platinum tetrachloride. After calcination in streaming nitrogen the catalyst was reduced with hydrogen. We studied the effects of temperatures of the calcination and the reduction on 1) the formation of hydrogen chloride in the course of calcination and the following reduction, 2) the dispersity of metallic platinum and 3) the catalytic activity for hydrogenation of 2-methyl-3-butene-2-ol and nitrobenzene in liquid phase. The catalytic activity was found to be proportional to the dispersity of platinum.
Contribution to the structure of aluminium caprolactamate based on the study of infrared and proton magnetic resonance spectra
Authors: Kříž Otomar , Čásenský Bohuslav
Published: October 2011

Aluminium caprolactamate (I) was prepared by the reaction of ε-caprolactam with isopropyliminoalane (II) in benzene. IR and 1H-NMR spectra of I in various solvents are described as well as low-temperature 1H-NMR spectra in hexane and dichlormethane. On the basis of these results together with the determination of molecular weights, structural arrangement was proposed for the dimer of I containing an eight-membered ring formed by two -O-C-N-bridges between aluminium atoms and two caprolactam ligands on each aluminium atom bonded through oxygen atom of carbonyl.
Binding of lead and chromium(III) cations to pectin
Authors: Malovíková Anna , Kohn Rudolf
Published: October 2011

Binding of Pb2+ ions to magnesium pectinates was studied by dialyzation technique in relation to their esterification degree (E) in the interval E = 0 to 84,7%, at an ionic strength I = 0.30. It has been found that the binding of Pb2+ ions to pectinates proceeds according to the theory of multiple equilibria. The values of stability constant K and selectivity coefficient KPbMg evidence the high selectivity of pectinates towards Pb2+ ions. Both those constants are, in contrast with value corresponding to other bivalent cations (e.g.Ca2+, Sr2+), independent on the esterification degree of pectin in the E 50% range. A strong binding of Pb2+ to carboxyl groups takes place also at a high esterification degree of pectin. The exchange of Cr3+ 3 K+ was investigated with a model preparation of potassium pectate crosslinked with epichlorhydrin by a batch method at various pH of equilibrium solutions (I = 0.15). Potassium pectate was shown to be a highly selective ion exchanger towards Cr3+. The binding of Cr3+ to pectate also occured in a sufficient extent at a low pH of equilibrium solutions (pH 3). Due to a very strong binding of Cr3+ to pectate a substantial shift of dissociation equilibrium of carboxyl groups in favour of further binding of Cr3+ ions occured.
Kinetics of reaction of 5-phenyl-1,3,4-thiadiazol-2-diazonium ion with water
Authors: Kaválek Jaromír , Janák Karel , Štěrba Vojeslav
Published: October 2011

5-Phenyl-1,3,4-thiadiazol-2-diazonium ion (I) is transformed into 2-amino-5-phenyl-1,3,4-thiadiazol (II) in diluted mineral acids. The reaction rate measured in solutions of diluted sulphuric acid reaches its maximum at concentrations of 2 to 2.5M-H2SO4. The reaction intermediate is 5-phenyl-1,3,4-thiadiazol-2-diazo hydroxide (III). The rate-limiting step in formation of III consists in base-catalyzed reaction of the diazonium ion I with water; it is 4.3 times slower in 0.1M-D2SO4 than in 0.1m-H2SO4. Ratio of the rate constants of the transformation of the diazo hydroxide III into the diazonium ion I and into the amine II increases rapidly with increasing sulphuric acid concentration.
Transformatins of deoxysugars
Authors: Kučár Štefan , Zámocký Juraj , Zemek Juraj
Published: October 2011

6-Deoxyaldoses are known to be more stable in alkaline medium than the corresponding aldoses. They undergo transformations with suitable reagents under appropriate reaction conditions to form the corresponding 6-deoxyhexuloses and C(3)-isomeric 6-deoxyhexuloses. Transformation of 6-deoxy-L-mannose and 6-deoxy-L-galactose affords 5-deoxy-L-arabino-hexulose, 6-deoxy-L-ribo-hexulose, 6-deoxy-L-xylo-hexulose.
Study of the reactions of dyes of the alizarin green series with UO22+ ions in the presence of cetyltrimethylammonium cation
Authors: Son Nguyen Truong , Ružička Eduard , Lasovský Jan
Published: October 2011

The reactions of four dyes of the alizarin green series with UO22+ ions in the presence of cetyltrimethylammonium cation (CTA+, S) were studied. At lower tenside concentration than the critical micelle concentration (cmc), defined ternary UO2L2S4 or UO2L2S2 complexes are formed in the solution. The stability constants of the complexes formed were determined and a procedure for the photometric determination of uranium and cetyltrimethylammonium was proposed.
Synthesis and separation of stereoisomers of 1,4- and 2,4-dihydroxyadamantanes
Authors: Vodička Luděk , Hlavatý Josef
Published: October 2011

Mixture of isomers of 1,4-dihydroxyadamantane has been prepared by reduction of 5-hydroxyadamantane-2-one, the isomeric 2,4-dihydroxyadamantanes have been prepared by reduction of adamantane-2,4-dione. The mixtures of 1,4- and 2,4-dihydroxyadamantanes have been separated into pure stereoisomers by elution chromatography on a silica gel column using benzene and diethyl ether as eluents. Structures of the individual isomers have been confirmed by NMR spectroscopy.
Nucleolytic enzymes of rape seedlings II. Unspecific acid phosphomonoester hydrolase
Authors: Rosenberg Ivan , Holý Antonín
Published: October 2011

Aqueous extracts of rape seedlings (Brassica napus L.) display phosphomonoesterase activity. The enzyme was purified gradually by chromatography on tert-butyl ester of Cellex P, affinity chromatography on sepharose 4B with linked p-aminophenyl(phenyl)thiophosphate or N6-(6-aminohexyl)adenosine 2'(3')-thiophosphate (final degree of purification 269x). The enzyme displayed activity toward various ribo- and 2'-deoxyribonucleotides, with preference for 3'-ribonucleotides, and to aryl or alkyl esters of phosphoric acid, ADP, ATP, inorganic pyrophosphate, as well as to nucleotide analogues containing acids of phosphorus with a small substituent on the phosphorus atom. The internucleotidic linkages of RNA and DNA are resistent. The enzyme is classified as an orthophosphate monoester hydrolase (EC 3.1.3.2).
The gauche effect on conformation. α-Substituted sulfones and N-substituted sulfonamides
Authors: Exner Otto , Engberts Jan B. F. N.
Published: October 2011

The dipole moments of α-halogenosulfones IIa-f in benzene solution revealed the conformation C, those of N-methyl-N-nitrosulfonamides IIIa-c the conformation F. In either case the conformational preference is governed by the gauche rule which may be worded in a modified version that symmetrical positions of polar bonds and/or of lone electron pairs are disfavoured. A lone electron pair appears to be more significant than a polar bond.
Temperature dependence of heats of vaporization, saturated vapour pressures and cohesive energies for a group of amines
Authors: Majer Vladimír , Svoboda Václav , Koubek Josef , Pick Jiří
Published: October 2011

The temperature dependences of heats of vaporization of propylamine, isopropylamine, butylamine, isobutylamine, sec-butylamine, cyclohexylamine, diethylamine and triethylamine and saturated vapour pressures of butylamine, isobutylamine, sec-butylamine and triethylamine were measured. The cohesive energies of amines studied in dependence on temperature were calculated from the experimental values.
System constant and its significance in industrial crystallisation
Authors: Nývlt Jaroslav , Broul Miroslav
Published: October 2011

Fundamental equations describing behaviour of the continuous stirred crystalliser in steady state include a system constant B, whose value strongly depends on selection of the size of initial crystals LN. To avoid this dependence and to see that the equations be applicable for crystalliser design also in the case when the value LN approaches zero, a general derivation of the dependence between the mean size of crystals L and specific output of the crystalliser mc has been derived on basis of the numerical nucleation rate. The derived relations do not include the quantity LN and they can be transformed by a simple arrangement to the published relations.
The heat capacity of water swollen poly(2-hydroxyethyl acrylate) above and below 0 °C
Authors: Biroš Ján , Madan Rattan Lal , Pouchlý Julius
Published: October 2011

The heat capacities of water swollen poly(2-hydroxyethyl acrylate) were determined with a DSC-2 calorimeter in the range 220-350 K for concentrations between 0 and 1.95 g water per 1 g polymer. The results confirm conclusions obtained in a preceding paper for the system poly[2-(2-hydroxyethoxy)ethyl methacrylate]-water. At temperatures above 0°C the partial specific heat capacity of water in the polymer is independent of composition and equal to the specific heat capacity of pure liquid water. This indicates that water sorbed in the polymer is not strongly bound. Analysis of data on the heat capacity below 0°C has led to a conclusion that at a water content below 0.2 g/g or at temperatures 230 K and lower, the crystallization of water from the gel is inhibited by factors which make impossible the attainment of thermodynamic equilibrium. Non-freezing water should not be identified with strongly bound water.
Berechnung von Potentialflachenausschnitten radikalischer Anlagerungsreaktionen an olefinische Doppelbindungen semiempirische Untersuchungen der Reaktion CH3 + C2H4
Authors: Gey Erhard , Kühnel Wilfried
Published: October 2011

Der Verlauf der Potentialfläche der Reaktion in der Nähe des Übergangsanstandes wurde durch verschiedene halbempirische Allvalenzelektronen-Verfahren (EHT, CNDO/2, INDO, CNDO/FK, MINDO/2, MINDO/2-17, MINDO/2', MINDO/3) untersucht. Die Abhängigkeit der Ergebnisse von dem open-shell Verfahren Molekülgeometrie und Parametrizierung wurde analysiert. Im Einklang mit den früheren Ergebnissen wurde gefunden, daß die MINDO/2 Methode die besten Informationen liefert. Berechnete Aktivierungsbarrieren, sowie Ladungs- und Spindichten werden diskutiert.
Kinetics of cyclohexene hydrogenation and of thiophene hydrogenolysis over cobalt-molybdenum catalysts of different composition
Authors: Vyskočil Vlastimil , Kraus Miloš
Published: October 2011

The kinetics of the title reactions has been measured at 350°C and atmospheric pressure on six Co-Mo-AL2O3 catalysts prepared by successive impregnation of the support with solutions of molybdenum and cobalt salts and containing these components in different ratios as well as on a commercial Cherox 36-00 catalyst. The activity of these catalysts depend strongly on their composition and showed similar trends for both reactions. Kinetic data were correlated by equations of Langmuir-Hishelwood type. Their adsorption coefficients have a similar value for different catalysts and all differences in the activity reflected in rate constants. Surface concentrations of molybdenum were determined by low temperature oxygen adsorption and were correlated with experimental rate constants.
Whole slide images for primary diagnostics in dermatopathology: a feasibility study
Authors: Al-Janabi Shaimaa , Huisman André , Vink Aryan , Leguit Roos J , Offerhaus G Johan A , ten Kate Fiebo J W , van Dijk Marijke R , van Diest Paul J
Published: October 2011

Background

During the last decade, whole slide images (WSI) have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation and quality assurance testing. However, WSI have not regularly been used for routine diagnosis, because of the lack of validation studies.

Aim

To test the validity of using WSI for primary diagnosis of skin diseases.

Materials and methods

100 skin biopsies and resections which had been diagnosed light microscopically one year previously were scanned at 20× magnification, and rediagnosed by six pathologists (every pathologist assessed his own cases), having the original clinical information available, but blinded to the original diagnoses. The WSI diagnoses were compared to the initial light microscopy diagnosis and classified as concordant, slightly discordant (without clinical consequences) or discordant.

Results

The light microscopy and the WSI based diagnosis were concordant in 94% of the cases. The light microscopy and WSI diagnosis were slightly discordant in 6% of the cases. For one of the slightly discrepant cases the WSI diagnosis was considered better, while the original diagnosis was preferred for the other five cases. There were no discordant cases with clinical or prognostic implications.

Conclusion

Primary histopathological diagnosis of skin biopsies and resections can be done digitally using WSI.
Dual-level direct dynamics study on the hydrogen abstraction reaction of fluorine atom with 1,1-difluoro-1-chloroethane
Authors: Wang Li , Liu Song , He Hongqing , Zhang Jinglai
Published: October 2011

The kinetic properties of the reaction of F atoms with CH2H′CF2Cl are investigated by a dual-level direct dynamics method. Optimized geometries and frequencies of all the stationary points and extra points along the minimum-energy path (MEP) are obtained at the MPW1K/6–311+G(d,p) level of theory. Two complexes with energy less than that of the reactants are located in the two reactant paths, respectively. The energy profiles of two reactions are refined with the interpolated single-point energies (ISPE) method at the G3(MP2)/MPW1K level. The rate constants are evaluated using the canonical variational transition state theory (CVT) with a small-curvature tunneling correction (SCT) over a wide range of temperature 200–2000 K. Agreement between the calculated CVT/SCT rate constant and the experimental value is good at 295 K. Our calculations show that the reaction path CH2H′CF2Cl + F → CH2CF2Cl + H′F (Ra) is the major reaction path below 400 K. Moreover, the contribution of CH2H′CF2Cl + F → CHH′CF2Cl + HF (Rb) to the whole reaction increases with the temperature increasing and exceeds path Ra to be the major reaction path.
PDGF enhances store-operated Ca2+ entry by upregulating STIM1/Orai1 via activation of Akt/mTOR in human pulmonary arterial smooth muscle cells
Authors: Ogawa Aiko , Firth Amy L. , Smith Kimberly A. , Maliakal Mary V. , Yuan Jason X.-J.
Published: October 2011

Platelet-derived growth factor (PDGF) and its receptor are known to be substantially elevated in lung tissues and pulmonary arterial smooth muscle cells (PASMC) isolated from patients and animals with pulmonary arterial hypertension. PDGF has been shown to phosphorylate and activate Akt and mammalian target of rapamycin (mTOR) in PASMC. In this study, we investigated the role of PDGF-mediated activation of Akt signaling in the regulation of cytosolic Ca2+ concentration and cell proliferation. PDGF activated the Akt/mTOR pathway and, subsequently, enhanced store-operated Ca2+ entry (SOCE) and cell proliferation in human PASMC. Inhibition of Akt attenuated the increase in cytosolic Ca2+ concentration due to both SOCE and PASMC proliferation. This effect correlated with a significant downregulation of stromal interacting molecule (STIM) and Orai, proposed molecular correlates for SOCE in many cell types. The data from this study present a novel pathway for the regulation of Ca2+ signaling and PASMC proliferation involving activation of Akt in response to upregulated expression of PDGF. Targeting this pathway may lead to the development of a novel therapeutic option for the treatment of pulmonary arterial hypertension.
Clinical Practice Associated with a Switch from and to Ziprasidone during Routine Inpatient Treatment of Patients with Schizophrenia
Authors: Müller Matthias J.
Published: October 2011

Ziprasidone (ZIP) shows a low propensity for metabolic side effects but can prolong QTc time. It is unclear how these features translate into clinical reality. Charts of inpatients with schizophrenia and switched from (ZIP−,n=27) or to ZIP (ZIP+,n=24) were reviewed. Clinical data including documented switch reasons were anonymously analyzed. Comorbidity, body mass index (BMI) at admission, illness severity, side effects, illness duration, and length of stay were comparable in both groups. About 2/3 ofZIP+were women (1/3 ofZIP−,P=0.035);ZIP+patients were younger (P=0.017), had higher BMI values (P=0.042), and received higher chlorpromazine equivalents before switch (P=0.004) whereas ZIP doses were comparable (136 versus 141 mg/d). More patients inZIP−versusZIP+were switched because of previous weight gain (P=0.006) and depression (P=0.085) whereas single reasons forZIP−versusZIP+were mainly persisting positive symptoms (P=0.089) and patients' choice (P=0.10). The results of the naturalistic study corroborate controlled trials.
Colocalization of Serum Amyloid A with Microtubules in Human Coronary Artery Endothelial Cells
Authors: Lakota Katja , Resnik Nataša , Mrak-Poljšak Katjuša , Sodin-Šemrl Snežna , Veranič Peter
Published: October 2011

Serum amyloid A (SAA) acts as a major acute phase protein and represents a sensitive and accurate marker of inflammation. Besides its hepatic origin, as the main source of serum SAA, this protein is also produced extrahepatically. The mRNA levels of SAA become significantly elevated following proinflammatory stimuli, as well as, are induced through their own positive feedback in human primary coronary artery endothelial cells. However, the intracellular functions of SAA are so far unknown. Colocalization of SAA with cytoskeletal filaments has previously been proposed, so we analyzed the colocalization of SAA with all three cytoskeletal elements: actin filaments, vimentin filaments, and microtubules. Immunofluorescent double‐labeling analyses confirmed by PLA method revealed a strict colocalization of SAA with microtubules and a very infrequent attachment to vimentin while the distribution of actin filaments appeared clearly separated from SAA staining. Also, no significant colocalization was found between SAA and endomembranes labeled with the fluorescent lipid stain DiO6. However, SAA appears to be located also unbound in the cytosol, as well as inside the nucleus and within nanotubes extending from the cells or bridging neighboring cells. These different locations of SAA in endothelial cells strongly indicate multiple potential functions of this protein.
Competition Kinetics of the Nonbranched‐Chain Addition of Free Radicals to Olefins, Formaldehyde, and Oxygen
Authors: Silaev M. M.
Published: October 2011

Five reaction schemes are suggested for the initiated nonbranched‐chain addition of free radicals to the multiple bonds of alkenes, formaldehyde, and oxygen. The schemes include reactions competing with chain propagation through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals. One of them—, , , , or —is relatively low‐reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations containing one to three parameters to be determined directly are set up using quasi‐steady‐state treatment. These equations provide good fits for the nonmonotonic (peaking) dependences of the formation rates of the molecular addition products (1 : 1 adducts) on the concentration of the unsaturated component in liquid homogeneous binary systems consisting of a saturated component (hydrocarbon, alcohol, etc.) and an unsaturated component (olefin, formaldehyde, or dioxygen). The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low‐reactive free radicals. A similar kinetic description is applicable to nonbranched‐chain free‐radical hydrogen oxidation. The energetics of the key radical‐molecule reactions is considered.
Local Cartilage Trauma as a Pathogenic Factor in Autoimmunity (One Hypothesis Based on Patients with Relapsing Polychondritis Triggered by Cartilage Trauma)
Authors: Cañas Carlos A. , Bonilla Abadía Fabio
Published: October 2011

In the recent years, it has been of great interest to study the binding mechanism between the innate and adaptive immune responses as interrelated processes for the development of multiple autoimmune diseases. Infection has been a well-known trigger of autoimmunity and trauma has been related as well too. Cryptogenic antigens release, recognition of pathogenic structure, and metabolic changes generated by both stimuli begin an inflammatory process which in turn activates the immune system amplifying T and B cell responses. The development of relapsing polychondritis after trauma may have a direct association with these events and in turn probably trigger autoimmune phenomena.
Significance of Dysregulated Metadherin and MicroRNA-375 in Head and Neck Cancer
Authors: Hui Angela B.Y. , Bruce Jeff P. , Alajez Nehad M. , Shi Wei , Yue Shijun , Perez-Ordonez Bayardo , Xu Wei , O'Sullivan Brian , Waldron John , Cummings Bernard , Gullane Patrick , Siu Lillian , Liu Fei-Fei
Published: October 2011

Purpose: Despite recent improvements in local control of head and neck cancers (HNC), distant metastasis remains a major cause of death. Hence, further understanding of HNC biology, and in particular, the genes/pathways driving metastasis is essential to improve outcome.

Experimental Design: Quantitative reverse transcriptase PCR (qRT-PCR) was used to measure the expression of miR-375 and metadherin (MTDH) in HNC patient samples. Targets of miR-375 were confirmed using qRT-PCR, Western blot analysis, and luciferase assays. Phenotypic effects of miR-375 reexpression and MTDH knockdown were assessed using viability (MTS), clonogenic survival, cell migration/invasion, as well as in vivo tumor formation assays. The prognostic significance of miR-375 or MTDH in nasopharyngeal carcinoma (NPC) was determined by comparing low versus high expression groups.

Results: MiR-375 expression was significantly reduced (P = 0.01), and conversely, MTDH was significantly increased (P = 0.0001) in NPC samples. qRT-PCR, Western blots, and luciferase assays corroborated MTDH as a target of miR-375. Reexpression of miR-375 and siRNA knockdown of MTDH both decreased cell viability and clonogenic survival, cell migration/invasion, as well as in vivo tumor formation. NPC patients whose tumors expressed high levels of MTDH experienced significantly lower survival and, in particular, higher distant relapse rates (5-year distant relapse rates: 26% vs. 5%; P = 0.005).

Conclusions: Dysregulation of miR-375 and MTDH may represent an important oncogenic pathway driving human HNC progression, particularly distant metastases, which is now emerging as a major cause of death for HNC patients. Hence, targeting this pathway could potentially be a novel therapeutic strategy by which HNC patient outcome could be improved. Clin Cancer Res; 17(24); 7539–50. ©2011 AACR.
Sweep Pattern Visual Evoked Potential Acuity in Children during Their Periods of Visual Development
Authors: Li Lu , Su Yu , Chen Chang-zheng , Feng Chao , Zheng Hong-mei , Xing Yi-qiao
Published: October 2011

Purpose: To study the clinical usage of sweep pattern visual evoked potential (SPVEP) acuity in children’s visual development periods and compare the amplitude-spatial frequency (A-SP) function regression method with the amplitude-logarithm of the visual angle (A-logVA) function regression method in evaluating the SPVEP acuity of children, especially those who have poor visual acuities. Methods: Twenty-six eyes of 26 amblyopic children (ages ranged from 3 to 12 years; mean age ± standard deviation 6.69 ± 1.74 years) and 31 eyes of normal children whose ages were matched with the amblyopic group were involved in this study. SPVEP acuity was recorded with GT-2000 NV (Guote Medical Apparatus Ltd., China) using sinusoidally modulated horizontal gratings with 10 different spatial frequencies from 0.99 to 12.89 cycles per degree to stimulate the retina. The averaging responses were displayed with the discrete Fourier transformation method. SPVEP acuity was assessed by both the A-SP function regression method and the A-logVA function regression method. The logarithm of minimal angle of resolution (logMAR) chart was used to obtain logMAR visual acuity. Results: In the normal group, logMAR acuity calculated by both the A-SP and A-logVA function regression methods had a significant correlation with SPVEP acuity. The average value of SPVEP acuity (by A-logVA) was closer to logMAR acuity. The difference of mean values between logMAR acuity and SPVEP acuity was significant in both regression methods. In the amblyopic group, it was SPVEP acuity (by A-logVA) that had a significant correlation with logMAR acuity, whereas the result was not significant when calculated by the A-SP function regression method (p = 0.515). The average value of SPVEP acuity (A-SP) was closer to logMAR acuity. The difference of mean values between logMAR acuity and SPVEP acuity (A-logVA) was significant; however, when compared with SPVEP acuity (A-SP), it was not significant (p = 0.174). In addition, SPVEP acuity may be overestimated or underestimated when it is compared with different logMAR visual acuities. Conclusion: SPVEP could be used to evaluate the visual acuity for normal children or those with poor visual acuity. Moreover, the A-logVA function regression method was more accurate than the A-SP function regression method in evaluating SPVEP acuity.
Improved Automated Screening of Diabetic Retinopathy
Authors: Oliveira Carlos M. , Cristóvão Luis M. , Ribeiro Maria Luisa , Abreu José R. Faria
Published: October 2011

Aim: To assess a two-step automated system (RetmarkerSR) that analyzes retinal photographs to detect diabetic retinopathy for the purpose of reducing the burden of manual grading. Methods: Anonymous images from 5,386 patients screened in 2007 were obtained from a nonmydriatic diabetic retinopathy screening program in Portugal and graded by an experienced ophthalmologist. RetmarkerSR earmarked microaneurysms, generating two outputs: ‘disease’ or ‘no disease’. A second-step analysis, based on coregistration, combining two visits, was subsequently performed in 289 patients who underwent repeated examinations in 2008. The study was extended by analyzing all referrals considered urgent by the ophthalmologist from 2001 to 2007. Results were compared with those obtained by manual grading. Results: The RetmarkerSR classified in a first-step analysis 2,560 patients (47.5%) as having ‘no disease’ and 2,826 patients (52.5%) as having ‘disease’, thus requiring manual grading. RetmarkerSR detected all eyes considered urgent referrals. The two-step analysis further reduced the number of false-positive results by 26.3%, indicating an overall sensitivity of 95.8% and a specificity of 63.2%. Conclusion: Automated grading of diabetic retinopathy may safely reduce the burden of grading patients in diabetic retinopathy screening programs. The novel two-step automated analysis system offers improved sensitivity and specificity over published automated analysis systems.
Ebf2 Marks Early Cortical Neurogenesis and Regulates the Generation of Cajal-Retzius Neurons in the Developing Cerebral Cortex
Authors: Chuang Shu-Mien , Wang Yue , Wang Qingjie , Liu Keh-Min , Shen Qin
Published: October 2011

Mammalian cortical neurogenesis occurs on a precise time schedule during development. The earliest born neurons form the preplate and later separate into layer 1, which includes Cajal-Retzius (C-R) neurons, and the subplate. The preplate and its derivatives play a critical role in regulating subsequent neuron migration and cortical lamination. Using an early B cell factor 2 (Ebf2)-enhanced green fluorescent protein (EGFP) transgenic mouse line, we show that Ebf2-EGFP is expressed in the preplate and persists in C-R neurons, allowing us to follow the development of these early born neurons. Therefore, Ebf2 is a genetic marker for preplate neurons from the earliest stage of their differentiation and C-R cells after the preplate is split. Additionally, we examined the function of Ebf2 in the development of C-R neurons using both lentiviral-mediated knock-down overexpression approaches to perturb Ebf2 expression. Our data show that Ebf2 overexpression increases the generation of early born neurons including C-R cells, while Ebf2 knock-down decreases it, without affecting the generation of other layer-specific neurons in vitro. These results indicate that Ebf2 is important for early cortical neurogenesis and regulates the generation of C-R neurons in the developing cerebral cortex.
Improving Outpatient Diabetes Care
Authors: Kirsh Susan , Hein Michael , Pogach Leonard , Schectman Gordon , Stevenson Lauren , Watts Sharon , Radhakrishnan Archana , Chardos John , Aron David
Published: October 2011

More than 20% of patients in the Veterans Health Administration (VHA) have diabetes; therefore, disseminating “best practices” in outpatient diabetes care is paramount. The authors’ goal was to identify such practices and the factors associated with their development. First, a national VHA diabetes registry with 2008 data identified clinical performance based on the percentage of patients with an A1c >9%. Facilities (n = 140) and community-based outpatient clinics (n = 582) were included and stratified into high, mid, and low performers. Semistructured telephone interviews (31) and site visits (5) were conducted. Low performers cited lack of teamwork between physicians and nurses and inadequate time to prepare. Better performing sites reported supportive clinical teams sharing work, time for non-face-to-face care, and innovative practices to address local needs. A knowledge management model informed our process. Notable differences between performance levels exist. “Best practices” will be disseminated across the VHA as the VHA Patient-Centered Medical Home model is implemented.
Effects of collagen-induced rheumatoid arthritis on amyloidosis and microvascular pathology in APP/PS1 mice
Authors: Park Sun Mi , Shin Jin Hee , Moon Gyeong Joon , Cho Sung Ig , Lee Yong Beom , Gwag Byoung Joo
Published: October 2011

Background

Evidence suggests that rheumatoid arthritis (RA) may enhance or reduce the progression of Alzheimer's disease (AD). The present study was performed to directly explore the effects of collagen-induced rheumatoid arthritis (CIA) on amyloid plaque formation, microglial activation, and microvascular pathology in the cortex and hippocampus of the double transgenic APP/PS1 mouse model for AD. Wild-type or APP/PS1 mice that received type II collagen (CII) in complete Freund's adjuvant (CFA) at 2 months of age revealed characteristics of RA, such as joint swelling, synovitis, and cartilage and bone degradation 4 months later. Joint pathology was accompanied by sustained induction of IL-1β and TNF-α in plasma over 4 weeks after administration of CII in CFA.

Results

CIA reduced levels of soluble and insoluble amyloid beta (Aβ) peptides and amyloid plaque formation in the cortex and hippocampus of APP/PS1 mice, which correlated with increased blood brain barrier disruption, Iba-1-positive microglia, and CD45-positive microglia/macrophages. In contrast, CIA reduced vessel density and length with features of microvascular pathology, including vascular segments, thinner vessels, and atrophic string vessels.

Conclusions

The present findings suggest that RA may exert beneficial effects against Aβ burden and harmful effects on microvascular pathology in AD.