bluuebunny/crossref_metadata_2025 huggingface dataset:
Proton Conductivity and Thermoelectric Effect in Magnesium Hydroxide
Authors: Freund Friedemann , Hösen Rudolf
Published: September 2012

The d.c. conductivity ∑(T) and the thermoelectric effect U(T) of high purity Mg(OH)2 powder were measured under dry N2/H2 gas at atmospheric pressure using Pd/H electrodes. When a field gradient in the order of 104 V / cm is applied, proton conductivity ∑p is observed between 170—240°C with a maximum around 210°C, superimposed to a background conductivity ∑0 of probably electronic nature due to transition metal impurities. The activation energy for the linear portion in the log ∑p vs. T−4 plot was found to be 2.1 eV. The thermoelectric effect U(T) gave positive potentials over the wole temperature range studied which corresponds to a p‐type semiconductor. Again between 170–240 °C a protonic contribution Up was found with a maximum around 225 °C. Its activation energy is also 2.1 eV. The results are consistent with the model of a proton tunnelling mechanism in Mg(OH)2 as a precursor to its decomposition to MgO.
Absorptionsspektren von halogenierten Methanen im Bereich von 275 bis 160 nm bei Temperaturen von 298 und 208 K
Authors: Hubrich C. , Zetzsch C. , Stuhl F.
Published: September 2012

Die Absorptionsspektren der halogenierten Methane CCl3F, CCl2F2, CHCl2F, CHClF2 und CH3Cl wurden im Wellenlängenbereich von 275 bis 160 nm bei 298 und 208 K bestimmt.
Kinetic Isotope Effect for the Reaction of a Hydrogen Atom with Cyclohexane‐h12, Cyclohexane‐d12 and Cyclohexane‐1, 1, 2, 2, 3, 3‐d6 as Studied by the Radiolysis of Water Vapor‐Cyclohexane Mixtures
Authors: Fujisaki N. , Gäumann T.
Published: September 2012

An attempt has been made to determine the kinetic isotope effects for the following reactions by using hydrogen atoms produced in the radiolysis of water vapor:

magnified image

The results are: kH/kD = (0.41 ± 0.05)exp(9.6 ± 0.4 kJ mol−1/RT) and kH/kD = (0.58 ± 0.06)exp(8.3 ± 0.4 kJ mol−1/RT), respectively, over the temperature range 353 K to 493 K; the errors correspond to standard deviations. The kinetic isotope effect has also been examined as a function of the ratios of c‐C6D12/c‐C6H12, total dose, total pressure and the total concentration of added cyclohexanes. Theoretical interpretation of the kinetic isotope effect has been made using the Bond‐Energy‐Bond‐Order (BEBO) method. Agreement between theoretical and experimental values is not satisfactory, even though the tunneling effect has been taken into account.
Atomabsorptionsmessungen zur Kinetik der Reaktion CH4 + O → CH3 + OH im Temperaturbereich 1500 ≤ T ≤ 2250 K
Authors: Roth P. , Just Th.
Published: September 2012

Durch direkte Messung des zeitlichen Verlaufes der O‐Atomkonzentration in der Reaktionszone hinter Stoßwellen konnte in Gemischen aus Argon mit geringen Konzentrationen an CH4 (10 ÷ 25 ppm) und N2O (5 ÷ 150 ppm) die Geschwindigkeitskonstante der Reaktion CH4 + O → CH3 + OH

in einem Temperaturbereich 1500 ≤ T ≤ 2250 K bestimmt werden. Die Gesamtdichte, bei der die Versuche ausgeführt wurden, lag bei 7 · 1010 cm−1.
Investigation of the Mass Transfer through Turbulent Boundary Layers in Liquid‐Liquid Emulsions
Authors: Dworak R. , Wendt Hartmut
Published: September 2012

Mass transfer through turbulent hydrodynamic boundary layers of liquid‐liquid emulsions (i.e. mass transport conditions for two phase electrolysis) has been investigated by measuring diffusion limited currents in quadratic tubes with large electrodes as well as with micro‐electrodes inserted into the macro electrode. As model systems 30 vol. % emulsions of CCl4 (p = 1.6 g/cm3) and n‐hexene (p = 0.6 g/cm3) with well defined drop diameters were used. The probe system was Fe(CN)3–4‐6 dissolved in the aqueous phase. Weakly enhanced (20–30%) mass transfer—as compared with one phase flow of identical streaming velocity—was observed in the CCl4 emulsion whereas for the emulsion of the n‐hexane which possesses a remarkably lower density than the aqueous phase the same mass transfer coefficients were measured as for one phase (aqueous) flow.—The micro‐electrode measurements showed that with CCl4 the quasi‐stationary laminar sublayer is compressed somewhat but is stabilized additionally. Under the applied conditions neither droplets of a lighter phase (n‐hexane) nor of a denser phase (CCl4) are able to penetrate down to the wall. Thus in the boundary layer some sort of demixing of the emulsions is observed which is shown to be due to friction damping of the droplet movement or differences in momentum of the supporting aqueous and the dispersed organic phase resp.
Temperature Dependence of Partial Molar Volumes of Binary Critical Mixtures Study of the System Isobutyric Acid/Water
Authors: Klein H. , Woermann D.
Published: September 2012

Measurements of the coefficient of thermal expansion of isobutyric acid/water mixtures of critical composition and of the partial molar volumes of the two components in the critical mixtures near the critical temperature Tc show: (a) The temperature dependence of the coefficient of thermal expansion is consistent with a logarithmic singularity. (b) The same is true for the temperature derivatives (∂Vi/∂T)P.xc of the partial molar volumes of the two components of the mixture (isobutyric acid i = 1, water i = 2). (c) The singular parts of (∂V1/∂T)P.xc and (∂V2/∂T)P.xc have opposite signs. Approaching Tc(∂T)P.xc decreases and (∂V1/∂T)P.xc increases. These findings are interpreted by assuming that isobutyric acid/water mixtures of critical composition exhibit hydrophobic effects near Tc.
Reaktionen von Wasserstoffatomen mit Hydroperoxylradikalen I. Bestimmung der spezifischen Geschwindigkeitskonstanten der Reaktionskanäle
Authors: Hack W. , Gg. Wagner H. , Hoyermann K.
Published: September 2012

Die Reaktion von Wasserstoff‐Atomen mit Hydroperoxyl‐Radikalen wurde in der Gasphase in zwei isotermen Strömungssystemen bei Drücken um 5 ± 102 [Pa] mit Helium als Trägergas bei 293 K untersucht. Die absoluten Konzentrationen von H, O und OH wurden mit der ESR gemessen. Als HO2‐Quelle diente die Reaktion: chemical structure image.

Die Geschwindigkeitskonstante dieser Reaktion wird zu: k1 (293 K) = (9,0 ± 1) 10−5 [cm6/mol2 sec] gemessen. – Aus der Messung der Konzentrationszeitprofile für kurze Reaktionszeiten wurden die spezifischen Geschwindigkeitskonstanten der Reaktionskanäle chemical structure image. bestimmt. Dabei wurde ausgenutzt, da13 durch NO eine homogene Katalyse der Reaktion (2a) nach: chemical structure image.
The Thermal Unimolecular Decompositions of CH3CD2Cl, CD3CD2Cl, and CH3CHCl2
Authors: Jonas R. , Heydtmann H.
Published: September 2012

The thermal decompositions of the deuterated ethyl chlorides CH3CD2Cl and CD3CD2Cl and of 1,1‐dichloroethane CH3CHCl2 were studied in a static system in the pressure range of 0.1–300 Torr. With a previously published rate constant for the decomposition of ethyl chloride [1] the following kinetic isotope effects were obtained for the high pressure limit in the range 710–770 K: magnified image.

The pressure dependent first order rate constants for the three reactions were compared with RRKM calculations, which used an activated complex model based on extended Hückel calculations [8].
H2‐Laser Photolysis Study of the Quenching of O2(b1g+) by H2 and D2
Authors: Kohse‐Höinghaus K. , Stuhl F.
Published: September 2012

An H2‐laser (δ ± 160 nm) was used to form metastable O2(b1 Σg+) molecules in the photolysis of O2. Monitoring the decay of the O2(b1 Σg+ → X3Σc−) emission in the presence of H2 and D2 yields rate constants of k(H2) = (8.3 ± 1.2) ± 10−13 and of k(D2) = (1.4 ± 0.2) ± 10−14 cm3 s−1 for the respective quenching process at 298 K. Preliminary results indicate similar temperature dependences (approximately 6.2 kJ mol−1 activation energy) for both reactions.
Theory of Micelle Formation Kinetics
Authors: Aniansson E. A. G.
Published: September 2012

A survey is given of a kinetic theory for micelle formation and disintegration at small deviations from equilibrium guided by a concept of a diffusionlike flow along an aggregation number axis. Two well separated relaxation times for the monomer concentration are predicted, the short one pertaining to the rearrangement of the micellar distribution at a constant number of micelles and the long one pertaining to the change in the number of micelles with a concomitant shift in the position of the mean aggregation number of the micelles. – A “reverse” case is shown to give a relaxation time distribution at complete variance with experimental results, general conditions are given for the occurrence of only one relaxation time in the rearrangement process, and the movements of the micellar distribution at moderate and large dilutions are described. – Finally a theoretical calculation of the disintegration rate constants is presented, its extension to the dynamics of partial exits of the amphiphilic molecules is sketched, and its inferences for monolayer and bilayer structures are pointed out.
The Dynamics of Micelle Formation
Authors: Hoffman H.
Published: September 2012

The article presents kinetic data on micellar systems that were obtained with relaxation techniques. Problems that are relevant to the following topics are discussed in detail:

Differences in the dynamic behaviour of micellar systems consisting of single‐ and double chain detergents.

The dynamics of micellar systems consisting of ionic detergents with hydrophobic counterions.

The dynamic behavior of micellar systems of perfluorated ionic detergents.

For most of the systems two relaxation times could be observed which very often showed characteristic differences in their temperature and concentration dependence. The two relaxation processes were associated according to the theory of micelle formation by G. Aniansson and S. Wall to the shift of the micellar distribution curve and the change of the micelle concentration. The following parameters were evaluated from the data: The residence times of the detergent molecules inside the micelles, the mean aggregation number of the micelles, the width of the micellar distribution curves and the concentrations of the micellar nuclei and their aggregation numbers.
A Numerical Computation of the Diffuse Double Layer and its Application to Spherical Colloidal Particles
Authors: Diekmann Stephan , Frahm Jens
Published: September 2012

A numerical method is presented which allows the computation of local ion concentrations as a function of distance from a charged surface. This has been applied to a micelle‐supported metal complexation reaction. The reactivity profile can be explained in the total range of surfactant concentration by making use of two different models of poly‐electrolyte solutions.
Reaktionen von Wasserstoffatomen mit Hydroperoxylradikalen II. Bestimmung der Geschwindigkeitskonstanten der Bruttoreaktion
Authors: Hack W. , Preuss A. W. , Wagner H. Gg. , Hoyermann K.
Published: September 2012

Die Reaktion von H‐Atomen mit Hydroperoxylradikalen wurde in zwei isothermen Strömungssystemen untersucht. Der Nachweis der HO2‐ und OH‐Radikale erfolgte mit der Methode der Laser‐Magnetischen‐Resonanz. Die HO2‐Radikale warden entweder in der Reaktion H + O2 + M → HO2 + M (Strömungssystem (A)) oder in der Reaktion F + H2O2 → HO2 + HF (Strömungssystem (B)) erzeugt. Das Trägergas war Helium bei einem Gesamtdruck von 500–800 Pa(A)bzw. 130 Pa(B). ‐ Die Geschwindigkeitskonstante k2 = k2a + k2b + k2c der Gesamtreaktion: magnified image ergibt sich einmal aus der Messung der quasistationären [HO2]‐Konzentration (A) und zum anderen direkt aus der Messung des [HO2]‐Konzentrations‐Zeit‐Profils in An‐ und Abwesenheit eines H‐Atomüberschusses (B). Der Wert der Geschwindigkeitskonstante beträgt: magnified image Simulationen der [OH]‐ und [HO2]‐Konzentrationsprofile in dem System H + O2 + M bestätigen den gemessenen Wert für die Geschwindigkeitskonstante k2.
Transport Through Polymer Membranes from the Liquid Phase
Authors: Meares Patrick
Published: September 2012

Transport from the liquid phase through homogeneous polymeric membranes has several features that distinguish it from gas and vapour permeation. The concentration of permeant in the polymer is usually high and has a large influence on diffusion coefficients. The driving force for transport, the gradient of chemical potential of the liquid, may be controlled by the application of a pressure but the functional form of the dependence of chemical potential on pressure is different in a liquid from that which applies in gas diffusion. Frequently the chemical potential gradients in liquid transport are small. ‐ The driving force may also be controlled by varying the composition of the liquid phases i. e. by setting up an osmotic pressure difference across the membrane. This can only be done with systems of more than one component and the study of transport from the liquid phase therefore leads readily into the study of several simultaneous fluxes and the possibilities of membrane selectivity and separation. ‐ This paper reviews work on the mechanisms of steady flow of, principally, organic liquids through polymer membranes under pressure from the liquid phase into either another liquid phase, as in hyperfiltration, or into a vapour phase as in pervaporation. The transport of a single liquid is considered first Then the flow of binary liquid mixtures is discussed and the mechanisms of separations or organic liquids by hyperfiltration and pervaporation are examined.
7Li and 23Na Nuclear Magnetic Relaxation in Poly(acrylic Acid) Solutions Containing a Paramagnetic Mn(II) Salt
Authors: Westra S. W. T. , Leyte J. C.
Published: September 2012

Large enhancements are observed for the 7Li and 23Na relaxation in solutions of poly(acrylic acid), containing Mn(II). The effect is explained by the evaluation of the increased metal ion concentrations near the polyion. — Using the cell model for polyelectrolyte solutions and the Poisson‐Boltzmann equation to obtain the distribution of the mobile ions with respect to the polymer, the calculated magnitudes of the enhancements and the dependences of the relaxation rates on the polymer charge density are found to be in agreement with the experimental data. — The condensation concept and other current two‐phase models are shown to be inadequate to account for the observed enhancements.
Magnetische Eigenschaften der Thuliumverbindungen Cs2MTmF6 (M = Na, K, Rb) und Cs2KTmX6 (X = Cl, Br)
Authors: Urland W.
Published: September 2012

Das magnetische Verhalten von Cs2NaTmF6, Cs2KTmF6, Cs2RbTmF6 Cs2KTmCl6 und Cs2KTmBr6 wird im Temperaturbereich von 2, 9 bis 251, 3 K untersucht. Die magnetischen Daten werden mit einem früher entwickelten Modell interpretiert, bei dem der Einfluß des Kristallfeldes theoretisch durch das Angular‐Overlap‐Modell beschrieben ist. Die erhaltenen Werte des Angular‐Overlap‐Parameters eσ (R) für die einzelnen Verbindungen werden untereinander verglichen und diskutiert Die Energiewerte der Kristallfeldniveaus des 3H6‐Grundzustandes werden berechnet.
Neue Ergebnisse zur chromatographischen Trennung und Anreicherung aller Seltenen Erden
Authors: Jung K. , Weuster W. , Specker H.
Published: September 2012

Alle Seltenen Erden können mit dem Laufmittel Diethylether/Bis‐(2‐ethylhexyl)phosphat/Salpetersäure (100:2:3,5) dünnschichtchromatographisch getrennt werden. Zweidimensional ist auch im Verhältnis 8000:1 eines Lanthanids zu allen anderen eine quantitative Trennung möglich. Als Anreicherung aus einer Uranmatrix gelingt eine Trennung Uran:SE im Verhältnis 109:1. Mittels Hochdruckflüssigkeits‐chromatographie lassen sich mit dem Laufmittel Di‐iso‐propylether/Tetrahydrofuran/Salpetersäure ohne Schwierigkeit 11 Lanthaniden, durch weitere Variation der Laufmittel (während der Elution) alle 14 Lanthaniden trennen, wie Vorversuche zeigen.
Prevalence of esophageal atresia among 18 international birth defects surveillance programs
Authors: Nassar Natasha , Leoncini Emanuele , Amar Emmanuelle , Arteaga‐Vázquez Jazmín , Bakker Marian K. , Bower Carol , Canfield Mark A. , Castilla Eduardo E. , Cocchi Guido , Correa Adolfo , Csáky‐Szunyogh Melinda , Feldkamp Marcia L. , Khoshnood Babak , Landau Danielle , Lelong Nathalie , López‐Camelo Jorge S. , Lowry R. Brian , McDonnell Robert , Merlob Paul , Métneki Julia , Morgan Margery , Mutchinick Osvaldo M. , Palmer Miland N. , Rissmann Anke , Siffel Csaba , Sìpek Antonin , Szabova Elena , Tucker David , Mastroiacovo Pierpaolo
Published: September 2012

BACKGROUND: The prevalence of esophageal atresia (EA) has been shown to vary across different geographical settings. Investigation of geographical differences may provide an insight into the underlying etiology of EA. METHODS: The study population comprised infants diagnosed with EA during 1998 to 2007 from 18 of the 46 birth defects surveillance programs, members of the International Clearinghouse for Birth Defects Surveillance and Research. Total prevalence per 10,000 births for EA was defined as the total number of cases in live births, stillbirths, and elective termination of pregnancy for fetal anomaly (ETOPFA) divided by the total number of all births in the population. RESULTS: Among the participating programs, a total of 2943 cases of EA were diagnosed with an average prevalence of 2.44 (95% confidence interval [CI], 2.35–2.53) per 10,000 births, ranging between 1.77 and 3.68 per 10,000 births. Of all infants diagnosed with EA, 2761 (93.8%) were live births, 82 (2.8%) stillbirths, 89 (3.0%) ETOPFA, and 11 (0.4%) had unknown outcomes. The majority of cases (2020, 68.6%), had a reported EA with fistula, 749 (25.5%) were without fistula, and 174 (5.9%) were registered with an unspecified code. CONCLUSIONS: On average, EA affected 1 in 4099 births (95% CI, 1 in 3954–4251 births) with prevalence varying across different geographical settings, but relatively consistent over time and comparable between surveillance programs. Findings suggest that differences in the prevalence observed among programs are likely to be attributable to variability in population ethnic compositions or issues in reporting or registration procedures of EA, rather than a real risk occurrence difference. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.
Does the cranial mesenchyme contribute to neural fold elevation during neurulation?
Authors: Zohn Irene E. , Sarkar Anjali A.
Published: September 2012

The central nervous system is derived from the neural plate, which undergoes a series of complex morphogenetic events resulting in formation of the neural tube in a process known as neurulation. The cellular behaviors driving neurulation in the cranial region involve forces generated by the neural tissue itself as well as the surrounding epithelium and mesenchyme. Of interest, the cranial mesenchyme underlying the neural plate undergoes stereotypical rearrangements hypothesized to drive elevation of the neural folds. As the neural folds rise, the hyaluronate‐rich extracellular matrix greatly expands resulting in increased space between individual cranial mesenchyme cells. Based on inhibitor studies, expansion of the extracellular matrix has been implicated in driving neural fold elevation; however, because the surrounding neural and epidermal ectoderm were also affected by inhibitor exposure, these studies are inconclusive. Similarly, treatment of neurulating embryos with teratogenic doses of retinoic acid results in altered organization of the cranial mesenchyme, but alterations in surrounding tissues are also observed. The strongest evidence for a critical role for the cranial mesenchyme in neural fold elevation comes from studies of genes expressed exclusively in the cranial mesenchyme that when mutated result in exencephaly associated with abnormal organization of the cranial mesenchyme. Twist is the best studied of these and is expressed in both the paraxial mesoderm and neural crest derived cranial mesenchyme. In this article, we review the evidence implicating the cranial mesenchyme in providing a driving force for neural fold elevation to evaluate whether there are sufficient data to support this hypothesis. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.
Parkhäuser und Tiefgaragen
Authors: Motzke Gerd
Published: September 2012

Im September 2010 ist die 2. Auflage des Merkblatts “Parkhäuser und Tiefgaragen” des Deutschen Beton‐ und Bautechnik‐Vereins E.V. erschienen. Dieses Merkblatt ist in der Kette der DIN 1045‐1:2008‐8 und dem Heft 525 des Deutschen Ausschusses für Stahlbeton zu sehen, das auf der Seite 19 auf das genannte Merkblatt verweist. Das Heft 525 wiederum ist mit der DIN 1045‐1:2008‐8 insofern verknüpft, als die Tabelle 3 im Abschnitt 6.3 unter der Überschrift Bewehrungskorrosion, ausgelöst durch Chloride, ausgenommen Meerwasser bei Nennung der Expositionsklasse XD3 in der Fußnote b) auf das Heft 525 des Deutschen Ausschusses für Stahlbeton verweist. Demnach ist das Merkblatt “Parkhäuser und Tiefgaragen” mittels Heft 525 mit der DIN 1045‐1:2008‐8 verbunden. Das wirft die Frage auf, ob das Merkblatt in jeder Hinsicht von besonderer Wertigkeit ist und gleichsam “geadelt” durch das Heft 525 und DIN‐Normen Ausdruck allgemein anerkannter Regeln der Technik ist.

Multi‐storey and underground car parks. On the legal validity of the leaflet of the same name of the German Society for Concrete and Construction Technology, September 2010 edition

In September 2010, the 2nd edition of the “Multi‐storey and underground car parks” leaflet was published by the German Society for Concrete and Construction Technology. This leaflet is seen as being within the DIN 1045‐1:2008‐8 series and booklet 525 of the German Committee for Reinforced Concrete, which refers on page 19 to the stated leaflet. Booklet 525 is in turn linked with DIN 1045‐1:2008‐8 inasmuch as Table 3 in Section 6.3 under the heading ”Reinforcement corrosion due to chlorides, excluding seawater”, when quoting exposure class XD3 refers in footnote b) to booklet 525 of the German Committee for Reinforced Concrete. Accordingly, the “Multi‐storey and underground car parks” leaflet is linked by booklet 525 with DIN 1045‐1:2008‐8. This poses the question as to whether the leaflet is of particular value in every respect and is similarly ”ennobled” by booklet 525 and DIN standards as an expression of being the generally acknowledged state‐of‐the‐art.
Quellfähige Acrylatgele – Eine Instandsetzungsalternative für Bewegungsfugen in Verkehrswasserbauwerken?
Authors: Maisner Matthias , Eßer Angelika , Kwenjeu Aristide , Westendarp Andreas , Schnellenbach‐Held Martina
Published: September 2012

Können quellfähige Acrylatgele möglicherweise eine interessante Alternative für die Instandsetzung von undichten Bewegungsfugen in Wasserbauwerken sein? Im Rahmen eines FuE‐Vorhabens wurden drei handelsübliche Acrylatgele für diesen Anwendungsfall untersucht, für den derzeit noch keine eigenen Regelungen bestehen. Zwei dieser Gele sind laut Herstellerangaben auch für die Instandsetzung von Fugen verwendbar. An den Gelen wurden ausgewählte physikalische Eigenschaften bestimmt. Die Verträglichkeit mit Bauelementen, mit denen die Gele im Fugenbereich Kontakt haben könnten, wurde anhand von Betonmodellen untersucht. Der Fokus der Untersuchungen richtete sich dabei auf etwaige nachteilige Auswirkungen auf Fugenbänder aus PVC und Elastomer sowie auf Einbauteile aus Stahl, inkl. Betonstahlbewehrung. Über die Injektion von Betonbauteilen wurde die Injektionsfähigkeit von Acrylatgelen gegen drückendes Wasser hinterfragt. Außerdem erfolgten Betrachtungen zur Umweltrelevanz derartiger Instandsetzungsmaßnahmen unter Verwendung von Acrylatgelen.

Swellable acrylatgels – An alternative maintenance method for expansion joints at navigable waterway constructions?

Could swellable acrylatgels offer an interesting application possibility for navigable waterway constructions? Within a research and development project three for other applications commercially used acrylatgels were investigated with respect to this application. The maintenance of expansion joints is currently unregulated. Concerning the manufacturer two gels are applicable for the maintenance of joints. Selected physical properties of the gels were determined. For statements concerning the compatibility with structural elements, which are in contact with the gels within the joint, concrete models were developed and constructed. The focus on the investigations was on the harmful impacts of waterstop types like PVC and Elastomer and of build‐in parts of steel, incl. concrete reinforcement steel. On investigations concerning the injectability of acrylatgels on reinforced concrete the applicability against heavy water pressure was questioned. Furthermore, considerations concerning the ecological relevance of such measures using acrylatgels were carried out.
Der entfesselte Baustoff
Authors: Rinke Mario , Kotnik Toni
Published: September 2012

Mit der massenhaften Einführung der industriellen Baustoffe Eisen und später Eisenbeton verändert sich das bisherige Verhältnis von Stofflichkeit zu der daraus entwickelten Konstruktionsform. Im Vergleich mit den bis dahin verwendeten Baustoffen leistet der mit dem Eisen kombinierte Beton viel mehr in fast unbeschränkten Formen mit sehr viel weniger konstruktiven Beschränkungen. Dabei müssen aber zunächst in langen Auseinandersetzungen alte typologische Konstruktionskonzeptionen des Formens und Fügens überwunden werden.

Im Eisenbeton erreicht die Verlagerung des Hauptaugenmerks des Konstrukteurs vom Fügen hin zum Formen seinen Höhepunkt: der gegossene Baustoff entledigt sich dem Zwang der Fügung und lässt sich fast beliebig formen. Er erreicht im Zusammenspiel der in ihm gezielt angeordneten Trageisen mit der äußeren Bauteilformung eine wesentliche Erweiterung seiner tragstrukturellen und formalen Leistungsfähigkeit. Erstmals kann ein Baustoff die gewünschte Erscheinung und eine tatsächliche Tragwirkung entkoppelt voneinander, aber in sich vereint, zusammenführen.

The unbound material. On the reception of the early reinforced concrete and its construction specificity

With the mass introduction of industrial construction materials such as iron and later, reinforced concrete, the existing relationship between materiality and the form which is developed out of it has been changing. Compared with previously used construction materials, the combination of concrete with iron provides much more capability, in almost unlimited forms and with much less structural restrictions. Thereby, however, old typological design concepts of shaping and joining have to first be overcome in lengthy disputes. The shift in the main focus of the designer from joining towards shaping reaches its high point in reinforced concrete: the cast building material disposes of the necessity of binding and can be shaped almost arbitrarily. It attains a substantial expansion of its structural and formal performance in the interaction of the iron specifically arranged to support it and the external formation of the components. For the first time, a building material can unite within itself the desired appearance and an actual structural effect that are decoupled from each other.
Die Bootshausbrücke in Sigmaringen
Authors: Pahl Gerhard , Schmidmeier Michael
Published: September 2012

Nachfolgend wird über die Planung und Realisierung einer besonderen Fußgängerbrücke über die Donau in Sigmaringen berichtet, bei welcher neben hohen gestalterischen Ansprüchen auch der Grad an Wirtschaftlichkeit sehr wichtig war. Für den Überbau kamen dabei Stahlbeton‐ und Spannbeton‐Fertigteile zum Einsatz, die mit den Pfeilern zu einem semiintegralen, monolithischen Dreifeldträgerrahmen verbunden wurden. Die Sichtbeton‐Oberflächen des Trogquerschnittes wurden durch Sandstrahlen bearbeitet.

The Bootshaus Bridge in Sigmaringen – a monolithic semi‐integral pedestrian bridge across the river Danube

The following report deals with the design and implementation of a special pedestrian and cyclist bridge across the river Danube in Sigmaringen, where not only the high demands on aesthetics but also the degree of efficiency were very important factors. The superstructure consists of precast armoured and prestressed concrete elements, which were connected to the bridge piers forming a semi‐integral, monolithic three‐span frame. The fairfaced concrete surface of the trough cross‐section was treated with sandblasting.
Einfluss des CO2‐Gehaltes, der Nach‐ und Vorbehandlung sowie der Luftfeuchtigkeit auf die Karbonatisierungsgeschwindigkeit von Beton
Authors: Hunkeler Fritz
Published: September 2012

Die Karbonatisierung von Beton war Mitte des letzten Jahrhunderts ein stark beachtetes Thema. Die damals entstandenen Schäden durch Bewehrungskorrosion führten zu entsprechenden Anpassungen in den Normen. Wegen den Veränderungen des Zement‐ und Betonmarktes steht die Dauerhaftigkeit von Beton heute erneut im Fokus des Interesses. Dabei geht es darum, die Leistungsfähigkeit von Beton vermehrt mit Prüfungen nachzuweisen. Der vorliegende Beitrag setzt sich mit der Prüfung des Karbonatisierungswiderstandes von Beton auseinander. Es wird gezeigt, dass die Prüfung mit 4 % CO2 möglich ist und erlaubt, verschiedene Einflüsse zu bewerten. Weiter werden Ergebnisse zum Einfluss der Nach‐ und Vorbehandlung sowie zum Einfluss der relativen Luftfeuchtigkeit vorgestellt.

Influence of CO2‐content, curing, preconditioning and relative humidity on the carbonation rate of concrete

In the middle of the last century the carbonation of concrete was an important issue. The damages then occurred, caused by the corrosion of the reinforcement, led to corresponding improvements of the standards. Due to changes in the cement and concrete market the durability of concrete is now again in the centre of attention. Thereby the performance of concrete has to be assured increasingly by testing. The present paper deals with the testing of the carbonation resistance of concrete. It is shown that the test with 4 % CO2 is feasible and allows evaluating various factors. Furthermore, results on the influence of curing, preconditioning (pre‐treatment) as well as of the relative humidity are presented.
Comparison of disease prevalence in two populations in the presence of misclassification
Authors: Tang Man‐Lai , Qiu Shi‐Fang , Poon Wai‐Yin
Published: September 2012

Comparing disease prevalence in two groups is an important topic in medical research, and prevalence rates are obtained by classifying subjects according to whether they have the disease. Both high‐cost infallible gold‐standard classifiers or low‐cost fallible classifiers can be used to classify subjects. However, statistical analysis that is based on data sets with misclassifications leads to biased results. As a compromise between the two classification approaches, partially validated sets are often used in which all individuals are classified by fallible classifiers, and some of the individuals are validated by the accurate gold‐standard classifiers. In this article, we develop several reliable test procedures and approximate sample size formulas for disease prevalence studies based on the difference between two disease prevalence rates with two independent partially validated series. Empirical studies show that (i) the Score test produces close‐to‐nominal level and is preferred in practice; and (ii) the sample size formula based on the Score test is also fairly accurate in terms of the empirical power and type I error rate, and is hence recommended. A real example from an aplastic anemia study is used to illustrate the proposed methodologies.
TRAINING STAFF TO INCREASE MANDING IN STUDENTS WITH AUTISM: TWO PRELIMINARY CASE STUDIES
Authors: Madzharova Maya S. , Sturmey Peter , Jones Emily A.
Published: September 2012

Two case studies evaluated two versions of behavioral skills training on peer‐to‐peer manding. Case Study 1 evaluated the full package of instructions, modeling, rehearsal, and feedback, and Case Study 2 used modeling and feedback only. Both case studies employed AB designs. In both case studies, staff increased correct teaching responses, and students increased the number of independent peer‐to peer mands. These pilot data suggest that staff can readily acquire teaching skills to increase peer‐to‐peer manding and that modeling and feedback may be sufficient to train staff to do so. Copyright © 2012 John Wiley & Sons, Ltd.
Flow‐based analysis using microfluidics–chemiluminescence systems
Authors: Al Lawati Haider A. J.
Published: September 2012

This review will discuss various approaches and techniques in which analysis using microfluidics–chemiluminescence systems (MF–CL) has been reported. A variety of applications is examined, including environmental, pharmaceutical, biological, food and herbal analysis. Reported uses of CL reagents, sample introduction techniques, sample pretreatment methods, CL signal enhancement and detection systems are discussed. A hydrodynamic pumping system is predominately used for these applications. However, several reports are available in which electro‐osmotic (EO) pumping has been implemented. Various sample pretreatment methods have been used, including liquid–liquid extraction, solid‐phase extraction and molecularly imprinted polymers. A wide range of innovative techniques has been reported for CL signal enhancement. Most of these techniques are based on enhancement of the mixing process in the microfluidics channels, which leads to enhancement of the CL signal. However, other techniques are also reported, such as mirror reaction, liquid core waveguide, on‐line pre‐derivatization and the use of an opaque white chip with a thin transparent seal. Photodetectors are the most commonly used detectors; however, other detection systems have also been used, including integrated electrochemiluminescence (ECL) and organic photodiodes (OPDs). Copyright © 2012 John Wiley & Sons, Ltd.
A study on the interaction between 3‐spiro‐piperidones and bovine serum albumin using spectroscopic approaches
Authors: Yu Xianyong , Yao Qing , Tao Hongwen , Yang Ying , Li Lei , Zheng Baishu , Zhu Shizhong
Published: September 2012

The interaction between 3‐spiro‐2′‐pyrrolidine‐3′‐spiro‐3″‐piperidine‐2,3″‐dione (PPD) and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence and UV–vis spectroscopy. Fluorescence emission data revealed that BSA (1.00 × 10‐5 mol/L) fluorescence was statically quenched by PPD at various concentrations, which implies that a PPD–BSA complex was formed. The binding constant (KA), the number of binding sites (n) and the specific binding site of the PPD with BSA were determined. Energy‐transfer efficiency parameters were determined and the mechanism of the interaction discussed. The thermodynamic parameters, ΔG, ΔH and ΔS, were obtained according to van't Hoff's equation, showing the involvement of hydrophobic forces in these interactions. The effect of PPD acting on the BSA conformation was detected by synchronous fluorescence. Copyright © 2012 John Wiley & Sons, Ltd.
Lighting‐Up of the Dye Malachite Green with Mercury(II)–DNA and Its Application for Fluorescence Turn‐Off Detection of Cysteine and Glutathione
Authors: Jia Xiaofang , Li Jing , Wang Erkang
Published: September 2012

This work describes a novel strategy for the highly sensitive and selective detection of cysteine (Cys) and glutathione (GSH) based on the Hg2+–AGRO100–malachite green (MG) complex system. The dye MG, which has a very low quantum yield in aqueous solution by itself, can bind with the thymine‐rich DNA AGRO100 in the presence of Hg2+ ions to generate a striking fluorescence intensity enhancement of 1000‐fold. As sulfur‐containing amino acids, Cys and GSH effectively sequester Hg2+ ions from the Hg2+–AGRO100–MG complex structure to switch the ‘lit‐up’ chemosensor to the ‘off’ state (about a 50‐fold fluorescence intensity decrease), thus providing a facile, but effective, method to probe for Cys/GSH. The fluorescence titration, UV absorption, CD, and Raman spectra provide some insight into the structural and chemical basis for the enhancement effect. The formation of the Hg2+–AGRO100–MG complex significantly affects the electronic structure and conformation of the MG molecule by leading to an extended π system, which is the likely origin of the observed striking fluorescence intensity enhancement. Notably, the proposed sensing platform exhibits exquisite selectivity and sensitivity toward Cys/GSH with limits of detection of 5 nM for Cys and 10 nM for GSH, respectively. Furthermore, the straightforward assay design avoids labeling of the probe, uses only commercially available materials, and still displays comparable sensitivity and excellent selectivity.
Synthesis and Characterization of Alkyl‐Imidazolium‐Based Periodic Mesoporous Organosilicas: A Versatile Host for the Immobilization of Perruthenate (RuO4−) in the Aerobic Oxidation of Alcohols
Authors: Karimi Babak , Elhamifar Dawood , Yari Omolbanin , Khorasani Mojtaba , Vali Hojatollah , Clark James H. , Hunt Andrew J.
Published: September 2012

The preparation and characterization of a set of periodic mesoporous organosilicas (PMOs) that contain different fractions of 1,3‐bis(3‐trimethoxysilylpropyl)imidazolium chloride (BTMSPI) groups uniformly distributed in the silica mesoporous framework is described. The mesoporous structure of the materials was characterized by powder X‐ray diffraction, transmission electron microscopy, and N2 adsorption–desorption analysis. The presence of propyl imidazolium groups in the silica framework of the materials was also characterized by solid‐state NMR spectroscopy and diffuse‐reflectance Fourier‐transform infrared spectroscopy. The effect of the BTMSPI concentration in the initial solutions on the structural properties (including morphology) of the final materials was also examined. The total organic content of the PMOs was measured by elemental analysis, whereas their thermal stability was determined by thermogravimetric analysis. Among the described materials, it was found that PMO with 10 % imidazolium content is an effective host for the immobilization of perruthenate through an ion‐exchange protocol. The resulting Ru@PI‐10 was then employed as a recyclable catalyst in the highly efficient aerobic oxidation of various types of alcohols.
Metastable Tetragonal Cu2Se Hyperbranched Structures: Large‐Scale Preparation and Tunable Electrical and Optical Response Regulated by Phase Conversion
Authors: Zhu Jinbao , Li Qiuyang , Bai Liangfei , Sun Yongfu , Zhou Min , Xie Yi
Published: September 2012

Despite the promising applications of copper selenide nanoparticles, an in‐depth elucidation of the inherent properties of tetragonal Cu2Se (β‐Cu2Se) has not been performed because of the lack of a facile synthesis on the nanoscale and an energy‐intensive strategy is usually employed. In this work, a facile wet‐chemical strategy, employing HCOOH as reducing agent, has been developed to access single‐crystalline metastable β‐Cu2Se hyperbranched architectures for the first time. The process avoids hazardous chemistry and high temperatures, and thus opens up a facile approach to the large‐scale low‐cost preparation of metastable β‐Cu2Se hyperbranched architectures. A possible growth mechanism to explain the formation of the β‐Cu2Se dendritic morphology has been proposed based on time‐dependent shape evolution. Further investigations revealed that the metastable β‐Cu2Se can convert into the thermodynamically more stable cubic α‐Cu2−xSe maintaining the dendritic morphology. An increase in electrical conductivity and a tunable optical response were observed under ambient conditions. This behavior can be explained by the oxidation of the surface of the β‐Cu2Se hyperbranched structures, ultimately leading to solid‐state phase conversion from β‐Cu2Se into superionic conductor α‐Cu1.8Se, which has potential applications in energy‐related devices and sensors.
Does a Photocatalytic Synergy in an Anatase–Rutile TiO2 Composite Thin‐Film Exist?
Authors: Kafizas Andreas , Carmalt Claire J. , Parkin Ivan P.
Published: September 2012

It has often been suggested that anatase–rutile mixtures/composites synergistically enhance photocatalysis. However, in the case of dense thin‐films containing an intimate mix of both anatase and rutile phases, such an effect has not been observed. In synthesising combinatorial films with graded film thickness and phase, and applying established photocatalytic mapping methods, we were able to assess how dense thin‐films of intimately mixed anatase–rutile mixtures affect photocatalytic performance. We found that no photocatalytic synergy between anatase–rutile composites (29≤rutile %≤83) within such dense thin‐film systems exists. In fact, an increased presence of rutile caused the photocatalytic activity to fall. This was explained by the unfavourable energetics in the multiple electron transfers required between several neighbouring rutile and anatase sites for the photo‐generated electron to reach the material’s surface; encouraging the trapping of electrons within the bulk and increasing the likelihood of charge recombination. The decrease in photocatalytic activity was found to vary linearly with rutile component.
Chiroptical Spectra of Tetrakis (+)‐3‐Heptafluorobutylrylcamphorate Ln(III) Complexes with an Encapsulated Alkali Metal Ion: Solution Structures as Revealed by Chiroptical Spectra
Authors: Shirotani Dai , Yamanari Kazuaki , Kuroda Reiko , Harada Takunori , Lunkley Jamie L. , Muller Gilles , Sato Hisako , Kaizaki Sumio
Published: September 2012

The preparation of tetrakis((+)‐hfbc) lanthanide(III) complexes with an encapsulated alkali metal and ammonium ions M[Ln((+)‐hfbc)4] (hereafter abbreviated as M‐Ln : (+)‐hfbc, (+)‐heptafluorobutyrylcamphorate; M, ammonium or benzyl ammonium ions as well as alkali metal ions) was reported and discussed. The electronic circular dichroism (CD) spectra in the intraligand π−π* transition of M–Ln were examined in view of the solvent effect. Here, the concentration, alkali metal, and ammonium ion dependences are compared with the solid CD, 5D0 ← 7F0(Eu(III)) excitation spectra, circularly polarized luminescence, and vibrational circular dichroism. It has been revealed that the dodecahedral eight coordinate DD‐8‐M‐Ln complexes in crystals are equilibrated between the diastereoselectively formed square antiprism eight coordinate SAPR‐8‐M‐Ln and [Ln((+)‐hfbc)3] in EtOH and CH3CN solutions or between the SAPR‐8‐M‐Ln and DD‐D2d(mmmm)‐8‐M‐Ln complexes in CHCl3 solution. The observed CD couplets are found to reflect the exciton CD couplets which are useful to determine the four‐bladed SAPR‐(llll) absolute configuration around the lanthanide(III) ion. Chirality 24:1055–1062, 2012. © 2012 Wiley Periodicals, Inc.
Advances in Targeting Voltage‐Gated Sodium Channels with Small Molecules
Authors: Nardi Antonio , Damann Nils , Hertrampf Torsten , Kless Achim
Published: September 2012

Blockade of voltage‐gated sodium channels (VGSCs) has been used successfully in the clinic to enable control of pathological firing patterns that occur in conditions as diverse as chronic pain, epilepsy, and arrhythmias. Herein we review the state of the art in marketed sodium channel inhibitors, including a brief compendium of their binding sites and of the cellular and molecular biology of sodium channels. Despite the preferential action of this drug class toward over‐excited cells, which significantly limits potential undesired side effects on other cells, the need to develop a second generation of sodium channel inhibitors to overcome their critical clinical shortcomings is apparent. Current approaches in drug discovery to deliver novel and truly innovative sodium channel inhibitors is next presented by surveying the most recent medicinal chemistry breakthroughs in the field of small molecules and developments in automated patch‐clamp platforms. Various strategies aimed at identifying small molecules that target either particular isoforms of sodium channels involved in specific diseases or anomalous sodium channel currents, irrespective of the isoform by which they have been generated, are critically discussed and revised.
Identification of Drugs Inducing Phospholipidosis by Novel in vitro Data
Authors: Muehlbacher Markus , Tripal Philipp , Roas Florian , Kornhuber Johannes
Published: September 2012

Drug‐induced phospholipidosis (PLD) is a lysosomal storage disorder characterized by the accumulation of phospholipids within the lysosome. This adverse drug effect can occur in various tissues and is suspected to impact cellular viability. Therefore, it is important to test chemical compounds for their potential to induce PLD during the drug design process. PLD has been reported to be a side effect of many commonly used drugs, especially those with cationic amphiphilic properties. To predict drug‐induced PLD in silico, we established a high‐throughput cell‐culture‐based method to quantitatively determine the induction of PLD by chemical compounds. Using this assay, we tested 297 drug‐like compounds at two different concentrations (2.5 μM and 5.0 μM). We were able to identify 28 previously unknown PLD‐inducing agents. Furthermore, our experimental results enabled the development of a binary classification model to predict PLD‐inducing agents based on their molecular properties. This random forest prediction system yields a bootstrapped validated accuracy of 86 %. PLD‐inducing agents overlap with those that target similar biological processes; a high degree of concordance with PLD‐inducing agents was identified for cationic amphiphilic compounds, small molecules that inhibit acid sphingomyelinase, compounds that cross the blood–brain barrier, and compounds that violate Lipinski’s rule of five. Furthermore, we were able to show that PLD‐inducing compounds applied in combination additively induce PLD.
Tackling Sample‐Related Artifacts in Membrane FCS Using Parallel SAF and UAF Detection
Authors: Winterflood Christian M. , Ruckstuhl Thomas , Reynolds Nicholas P. , Seeger Stefan
Published: September 2012

The complex shape and plasticity of cells is an intricate issue for the measurement of molecular diffusion in plasma membranes by fluorescence correlation spectroscopy (FCS). An important precondition for accurate diffusion measurements is a sufficient flatness of the membrane over the considered region and the absence of non‐membrane‐bound fluorescence diffusion. A method is presented to identify axial motion components caused by a non‐ideal geometry of the membrane based on simultaneous measurement of the fluorescence emitted above and below the critical angle of the specimen/glass interface. Thereby, two detection volumes are generated that are laterally coincident, but differ in their axial penetration of the specimen. The similarity between the intensity tracks of the supercritical angle fluorescence (SAF) and the undercritical angle fluorescence (UAF) strongly depends on the membrane flatness and intracellular fluorescence, and can help to avoid sample‐related artifacts in the diffusion measurement.
Enhancement of Iodine–Hydride Interaction by Substitution and Cooperative Effects in NCX–NCI–HMY Complexes
Authors: Li Qing‐Zhong , Sun Liang , Liu Xiao‐Feng , Li Wen‐Zuo , Cheng Jian‐Bo , Zeng Yan‐Li
Published: September 2012

The NCX‐NCI‐HMY (X=H, Cl, Br, I, Li; M=Be, Mg; Y=H, Li, Na) trimers are investigated to find ways to enhance the iodine–hydride interaction. The interaction energy in the NCI–HMH dimer is −2.87 and −5.87 kcal mol−1for M=Be and Mg, respectively. When the free H atom in the NCI–HMH dimer is replaced with an alkali atom, the interaction energy is enhanced greatly. When NCX is added into this dimer, the interaction energy of the iodine–hydride interaction is increased by 9–45 % and its increased percentage follows the order X=Cl<Br<H<I<Li and M=Be<Mg. The combination of the alkali substitution and the cooperativity results in a more prominent enhancing effect. The largest interaction energy is found for the NCLi–NCI–HMgLi trimer (−7.03 kcal mol−1). The influence of the I⋅⋅⋅H interaction on the X⋅⋅⋅N interaction is also studied in the trimers. Both types of interactions are analyzed with NBO, AIM, and MEP. The interaction energy in the trimer is also unveiled by a many‐body analysis.