bluuebunny/crossref_metadata_2025 huggingface dataset:
Historical variation and trends in storminess along the Portuguese South Coast
Authors: Almeida L. P. , Ferreira Ó. , Vousdoukas M. I. , Dodet G.
Published: September 2011

Abstract. This work investigates historical variation and trends in storm climate for the South Portugal region, using data from wave buoy measurements and from modelling, for the period 1952 to 2009. Several storm parameters (annual number of storms; annual number of days with storms; annual maximum and mean individual storm duration and annual 99.8th percentile of significant wave height) were used to analyse: (1) historical storminess trends; (2) storm parameter variability and relationships; and (3) historical storminess and its relationship to the North Atlantic Oscillation (NAO). No statistically significant linear increase or decrease was found in any of the storm parameters over the period of interest. The main pattern of storm characteristics and extreme wave heights is an oscillatory variability with intensity peaks every 7–8 yr, and the magnitude of recent variations is comparable with that of variations observed in the earlier parts of the record. In addition, the results reveal that the NAO index is able to explain only a small percentage of the variation in storm wave height, suggesting that more local factors may be of importance in controlling storminess in this region.
On the influence of model physics on simulations of Arctic and Antarctic sea ice
Authors: Massonnet F. , Fichefet T. , Goosse H. , Vancoppenolle M. , Mathiot P. , König Beatty C.
Published: September 2011

Abstract. Two hindcast (1983–2007) simulations are performed with the global, ocean-sea ice models NEMO-LIM2 and NEMO-LIM3 driven by atmospheric reanalyses and climatologies. The two simulations differ only in their sea ice component, while all other elements of experimental design (resolution, initial conditions, atmospheric forcing) are kept identical. The main differences in the sea ice models lie in the formulation of the subgrid-scale ice thickness distribution, of the thermodynamic processes, of the sea ice salinity and of the sea ice rheology. To assess the differences in model skill over the period of investigation, we develop a set of metrics for both hemispheres, comparing the main sea ice variables (concentration, thickness and drift) to available observations and focusing on both mean state and seasonal to interannual variability. Based upon these metrics, we discuss the physical processes potentially responsible for the differences in model skill. In particular, we suggest that (i) a detailed representation of the ice thickness distribution increases the seasonal to interannual variability of ice extent, with spectacular improvement for the simulation of the recent observed summer Arctic sea ice retreats, (ii) the elastic-viscous-plastic rheology enhances the response of ice to wind stress, compared to the classical viscous-plastic approach, (iii) the grid formulation and the air-sea ice drag coefficient affect the simulated ice export through Fram Strait and the ice accumulation along the Canadian Archipelago, and (iv) both models show less skill in the Southern Ocean, probably due to the low quality of the reanalyses in this region and to the absence of important small-scale oceanic processes at the models' resolution (~1°).
Inflammation during fetal and neonatal life: Implications for neurologic and neuropsychiatric disease in children and adults
Authors: Hagberg Henrik , Gressens Pierre , Mallard Carina
Published: September 2011

Inflammation is increasingly recognized as being of both physiological and pathological importance in the immature brain. The rationale of this review is to present an update on this topic with focus on long‐term consequences of inflammation during childhood and in adults. The immature brain can be exposed to inflammation in connection with viral or bacterial infection during pregnancy or as a result of sterile central nervous system (CNS) insults. Through efficient anti‐inflammatory and reparative processes, inflammation may resolve without any harmful effects on the brain. Alternatively, inflammation contributes to injury or enhances CNS vulnerability. Acute inflammation can also be shifted to a chronic inflammatory state and/or adversely affect brain development. Hypothetically, microglia are the main immunocompetent cells in the immature CNS, and depending on the stimulus, molecular context, and timing, these cells will acquire various phenotypes, which will be critical regarding the CNS consequences of inflammation. Inflammation has long‐term consequences and could speculatively modify the risk of a variety of neurological disorders, including cerebral palsy, autism spectrum disorders, schizophrenia, multiple sclerosis, cognitive impairment, and Parkinson disease. So far, the picture is incomplete, and data mostly experimental. Further studies are required to strengthen the associations in humans and to determine whether novel therapeutic interventions during the perinatal period can influence the occurrence of neurological disease later in life. Ann Neurol 2012;
Staudinger‐Ligation als Methode zur Biokonjugation
Authors: van Berkel Sander S. , van Eldijk Mark B. , van Hest Jan C. M.
Published: September 2011

Der deutsche Chemiker Hermann Staudinger beschrieb 1919 als erster die Reaktion eines Azids mit einem Phosphan. Es war jedoch erst vor Kurzem, dass Bertozzi et al. das Potenzial dieser Reaktion als Biokonjugationsmethode erkannten und die so genannte Staudinger‐Ligation einführten. Wegen des bioorthogonalen Charakters sowohl der Azid‐ als auch der Phosphan‐Funktion ergaben sich für die Staudinger‐Ligation zahlreiche Anwendungen in verschiedenen komplexen biologischen Systemen. Die Staudinger‐Ligation wird beispielsweise zur Markierung von Glycanen, Lipiden, DNA und Proteinen genutzt. Darüber hinaus wird die Staudinger‐Ligation zur Bildung von Glycopeptiden, Mikroarrays und funktionalen Biopolymeren eingesetzt. Im neu entstehenden Gebiet der bioorthogonalen Ligations‐Strategien hat die Staudinger‐Ligation einen hohen Standard gesetzt, mit dem die meisten neuen Methoden verglichen werden. In diesem Aufsatz werden jüngste Entwicklungen und neue Anwendungen der Staudinger‐Ligation zusammengefasst.
Staudinger Ligation as a Method for Bioconjugation
Authors: van Berkel Sander S. , van Eldijk Mark B. , van Hest Jan C. M.
Published: September 2011

In 1919 the German chemist Hermann Staudinger was the first to describe the reaction between an azide and a phosphine. It was not until recently, however, that Bertozzi and co‐workers recognized the potential of this reaction as a method for bioconjugation and transformed it into the so‐called Staudinger ligation. The bio‐orthogonal character of both the azide and the phosphine functions has resulted in the Staudinger ligation finding numerous applications in various complex biological systems. For example, the Staudinger ligation has been utilized to label glycans, lipids, DNA, and proteins. Moreover, the Staudinger ligation has been used as a synthetic method to construct glycopeptides, microarrays, and functional biopolymers. In the emerging field of bio‐orthogonal ligation strategies, the Staudinger ligation has set a high standard to which most of the new techniques are often compared. This Review summarizes recent developments and new applications of the Staudinger ligation.
Preparation, characterization, and improvement of hollow epoxy particle‐toughened vinyl ester composites for high‐end applications
Authors: Foon Low Lay , Abu Bakar Azhar Bin
Published: September 2011

Spherical hollow epoxy particles (HEPs) that can serve as advanced reinforcing fillers for vinyl ester thermosets were prepared using the water‐based emulsion method. The HEP fillers were incorporated into the vinyl ester matrices at different loading amounts, ranging from 0 to 9 wt %, to reinforce and toughen the vinyl ester composite. The optimum mechanical properties of the HEP‐toughened epoxy composite can be achieved by the addition of 5 wt % HEP filler into the vinyl ester matrices. The toughening and strengthening of the epoxy composites involved the interlocking of vinyl ester resins into the pore regions on the HEP fillers. The toughening and interlocking mechanisms of HEP‐toughened vinyl ester composites were also proposed and discussed. The addition of HEP fillers into vinyl ester matrices increased the glass transition temperature (Tg) and thermal stability of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Morphological and physical evolutions of aramid fibers aged in a moderately alkaline environment
Authors: Derombise G. , van Schoors L. Vouyovitch , Bourmaud A. , Davies P.
Published: September 2011

The recent use of aramid fibers in geotextiles for ground reinforcement raises fundamental durability issues, in particular in alkaline soils where they are subjected to hydrolysis. To study the degradation mechanisms in such an environment, accelerated aging at pH 9 and at pH 11 has been carried out for up to one and a half years. This work describes the morphological evolutions that occur and the morphology‐properties relationship during aging in moderately alkaline environments. The decreases in apparent density are larger at pH 9 than at pH 11, whereas the bulk chemical degradation is more extensive at pH 11 than at pH 9. Scanning electron microscopy micrographs of chemically etched fibers and the measurements of the local elastic modulus by nanoindentation support these results. Finally, this study has indicated an inverse correlation between the porosity level and the tensile strength. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Time‐of‐flight mobilities for conducting dendrimers composed of p‐phenylenevinylene dendron and triphenylamine surface group
Authors: Mizusaki Masanobu
Published: September 2011

Charge‐carrier transport property of the conducting dendrimer films composed of p‐phenylenevinylene with generation numbers of two and three as a dendron and triphenylamine as a surface group, which were prepared by spin‐coating from the chloroform solutions, was investigated by a time‐of‐flight technique. For both dendrimer films, hole‐carrier transport took place preferentially compared with electron‐carrier transport, and typical dispersive hole‐carrier transport was observed. The hole‐carrier drift mobilities of the two‐generation dendrimer film were one order of magnitude larger than those of the three‐generation dendrimer film. The difference of the hole‐carrier drift mobilities between the two‐generation and three‐generation dendrimers was due to the difference of the molecular geometric structure and/or the difference of the molecular weight ratio of nitrogen atom in the triphenylamine unit to the dendrimer molecule. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
PE/OMMT nanocomposites prepared by in situ polymerization approach: Effects of OMMT‐intercalated catalysts and silicate modifications
Authors: Huang Ying‐Juan , Qin Ya‐Wei , Dong Jin‐Yong , Zhao Xutao , Hu Xuteng
Published: September 2011

In this article, the surfactants, (2‐hydroxylethyl) octadecyl dimethylammonium nitrate (OH‐C18), hexadecyltrimethylammonium bromide(C16), and mixture of trimethylchlorosilane (TM) and OH‐C18 were ion‐exchanged with cations in the montmorillonite (MMT) to generate three organic MMTs (named as OH‐C18‐MMT, C16‐MMT, and MMMT), leading to different environments of catalyst species in MMT interlayer gallery. Et[Ind]2ZrCl2 (abbreviated as EI) was supported on the above three types of OMMTs to prepare the PE/OMMT nanocomposites via in situ polymerization. By contrast, EI/MMMT showed higher activity than EI/OH‐C18‐MMT and EI/C16‐MMT under the same polymerization conditions. The other two types of catalysts, such as [(tert‐Bu)NSi(Me2)C5Me4]TiCl2 (CGCT) and Bis[N‐(3‐tert‐butylsalicylidene)anilinato] titanium (IV) dichloride (FI) were also supported on the OH‐C18‐MMT for in situ ethylene polymerization. It was found that the activity of FI/OH‐C18‐MMT for ethylene polymerization was much lower than the other two corresponding catalysts under the similar reaction conditions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Graft copolymers synthesis by dynamic covalent reorganization of polycaprolactone and poly(ethylene‐co‐vinyl alcohol)
Authors: Touhtouh S. , Becquart F. , Taha M.
Published: September 2011

Dynamic covalent reorganization of polycaprolactone (PCL) and poly(ethylene‐co‐vinyl alcohol) (EVOH) were realized by solvent free transesterification reactions. Organometallic and organic catalysts effect on these reactions was first evaluated from kinetic studies on small molar mass model reactants. Kinetic constants and activation energies of these second order reverse reactions were calculated. At the higher temperatures, side reactions were observed; they were identified as being principally dehydration reactions. Reactions conducted onto polymers were slower than those on model reactions. This was due to the immiscibility of the used polymers resulting in diffusion controlled reactions. Two competitive types of reactions were detected, since at the catalyst addition, fast induced reorganization of PCL leading to low PCL molar mass decreases the mixing torque, followed by grafting reactions of PCL onto EVOH, resulted in an important increase of the mixing torque. Substitution rate of the EVOH hydroxyl groups were measured up to 14% by 1H‐NMR spectroscopy. Increasing substitution rate leaded to a decrease of the copolymer crystallinity and the more substituted copolymers were amorphous. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal, dynamic‐mechanical, and dielectric properties of surfactant intercalated graphite oxide filled maleated polypropylene nanocomposites
Authors: Wang Yeh , Tsai Huai‐B.
Published: September 2011

Graphite oxide (GO) and amine surfactant intercalated graphite oxide (GOS) filled maleated polypropylene (PPgMA) nanocomposites were prepared directly by solution blending. In this study, the effects of the surfactant intercalation on the crystalline structure, thermo‐mechanical, and dielectric properties of PPgMA/GO and GOS composites are reported. Wide‐angle X‐ray diffraction exhibited a lower intensity diffraction peak of the monoclinic (α) phase of PPgMA for PPgMA/GOS composites compared with the unfilled sample. Differential scanning calorimetry exhibited a single characteristic melting peak of monoclinic (α) crystalline phase. The incorporation of GOS hardly showed any change in Tm. However, the significant decrease in the melting enthalpy of PPgMA/GOS composite, which was lower than that of GO filled PPgMA, demonstrated the high degree of dispersion of the GOS flakes in the PPgMA matrix. Dynamical mechanical analysis indicated that incorporation of GO or GOS into PPgMA increased both the storage modulus and the glass transition temperature, due to the hydrogen bonding between GO and the maleic anhydride group of PPgMA. Dielectric analyzer showed significant increase in both dielectric permittivity and dielectric loss at high temperature regimes in the GOS nanocomposites. The finely dispersed GOS in the PPgMA matrix manifested the interfacial polarization, which gave rise to much greater ε′ and ε″ than that of PPgMA/GO hybrid. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
New organic–inorganic hybrid membranes based on sulfonated polyimide/aminopropyltriethoxysilane doping with sulfonated mesoporous silica for direct methanol fuel cells
Authors: Geng Lei , He Yao , Liu Dan , Lü Changli
Published: September 2011

A series of novel composite methanol‐blocking polymer electrolyte membranes based on sulfonated polyimide (SPI) and aminopropyltriethoxysilane (APTES) doping with sulfonated mesoporous silica (S‐mSiO2) were prepared by the casting procedure. The microstructure and properties of the resulting hybrid membranes were extensively characterized. The crosslinking networks of amino silica phase together with sulfonated mesoporous silica improved the thermal stability of the hybrid membranes to a certain extent in the second decomposition temperature (250–400°C). The composite membranes doping with sulfonated mesoporous silica (SPI/APTES/S‐mSiO2) displayed superior comprehensive performance to the SPI and SPI/APTES membranes, in which the homogeneously embedded S‐mSiO2 provided new pathways for proton conduction, rendered more tortuous pathways as well as greater resistance for methanol crossover. The hybrid membrane with 3 wt % S‐mSiO2 into SPI/APTES‐4 (SPI/A‐4) exhibited the methanol permeability of 4.68 × 10−6 cm2 s−1at 25°C and proton conductivity of 0.184 S cm−1 at 80°C and 100%RH, while SPI/A‐4 membrane had the methanol permeability of 5.16 × 10−6 cm2 s−1 at 25°C and proton conductivity of 0.172 S cm−1 at 80°C and 100%RH and Nafion 117 exhibited the values of 8.80 × 10−6 cm2 s−1 and 0.176 S cm−1 in the same test conditions, respectively. The hybrid membranes were stable up to about 80°C and demonstrated a higher ratio of proton conductivity to methanol permeability than that of Nafion117. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A finite piece method for simulating polymer melt flows in extrusion sheet dies
Authors: Li Yong , Zheng Jianrong , Xia Chunmin , Zhou Wei
Published: September 2011

A finite piece method is proposed to simulate three‐dimensional slit flows in extrusion sheet dies in this paper. The simulations concern incompressible fluids obeying different constitutive equations: generalized Newtonian (Carreau‐Yasuda law), and viscoelastic Phan‐Thien Tanner (PTT) models. Numerical simulations are carried out for the isothermal and nonisothermal flows of polymer melt through sheet dies. The Picard iteration method is utilized to solve nonlinear equations. The results of the finite piece method are compared with the three‐dimensional (3D) finite element method (FEM) simulation and experiments. At the die exit, the relative error of the volumetric flow between the finite piece method and the 3D FEM is below 1.2%. The discrepancy of the pressure distributions does not exceed 6%. The Maximum error of the uniformity index between the simulations and experiments is about 2.3%. It shows that the solution accuracy of the finite piece method is excellent, and a substantial amount of computing time and memory requirement can be saved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and Anti‐Bacterial Activity of Some Heterocyclic Chalcone Derivatives Bearing Thiofuran, Furan, and Quinoline Moieties
Authors: Zheng Chang‐Ji , Jiang Sheng‐Ming , Chen Zhen‐Hua , Ye Bai‐Jun , Piao Hu‐Ri
Published: September 2011

36 Novel heterocyclic chalcone derivatives were synthesized and tested for their anti‐bacterial activity. Some compounds presented good anti‐microbial activities against Gram‐positive bacteria (including the multidrug‐resistant clinical isolates). This class of compounds presented high potency against Streptococcus mutans, among which the derivatives F2 with an MIC of 2 µg/mL was as active as the standard drug (norfloxacin) and less active than oxacillin. All the compounds did not inhibit the growth of Gram‐negative bacteria (Escherichia coli CCARM 1924 or Escherichia coli CCARM 1356) at 64 µg/mL.
N‐Acetyl‐5‐arylalkoxytryptamine Analogs: Probing the Melatonin Receptors for MT1‐Selectivity
Authors: Markl Christian , Clafshenkel William P. , Attia Mohamed I. , Sethi Shalini , Witt‐Enderby Paula A. , Zlotos Darius P.
Published: September 2011

A series of melatonin analogs obtained by the replacement of the ether methyl group with larger arylalkyl and aryloxyalkyl substituents was prepared in order to probe the melatonin receptors for MT1‐selectivity. The most MT1‐selective agents 11 and 15 were substituted with a Ph(CH2)3 or a PhO(CH2)3 group. Compounds 11 and 15 displayed 11.5‐fold and 11‐fold higher affinity for the MT1 receptors than for the MT2 subtype. Interestingly, in our binding assay 11 and 15 have shown considerably higher MT1‐affinity and selectivity than the reference ligand, the dimeric agomelatine 1a.
Empfehlung EB 102 des Arbeitskreises “Baugruben“ der DGGT zur Anwendung des Bettungsmodulverfahrens
Authors: Hettler Achim
Published: September 2011

Der Arbeitskreis “Baugruben“ hat sich in den letzten Jahren ausführlich mit der Empfehlung EB 102 zur Anwendung des Bettungsmodulverfahrens beschäftigt. Auf der Grundlage zahlreicher Vergleichsberechnungen wurde die Empfehlung überarbeitet. Der neue Entwurf wird im folgenden Beitrag der Fachwelt zur Diskussion vorgestellt. Die wesentlichen Neuerungen werden in einem Kommentar erläutert.

Recommendation EB 102 “Modulus of subgrade reaction method“ of the working group for excavations of the German Society for Geotechnical Engineering. During the last years the working group for excavations has discussed the recommendation EB 102 “Modulus of subgrade reaction method” in detail. Basing on intensive investigations a revised version is now presented to the public for discussion. The essential new proposals are illustrated in a comment.
Zur Standsicherheit suspensionsgestützter Eckschlitzwandelemente
Authors: Triantafyllidis Theodoros , Vogelsang Jakob , Grandas‐Tavera Carlos Eduardo
Published: September 2011

Der Nachweis der Standsicherheit von nicht‐ebenen Erdschlitzen, z. B. an einer Schlitzwandecke, ist mit dem vorhandenen Normenwerk nicht abgedeckt und auch nicht einfach zu erbringen. Dieser Artikel soll daher einige Erkenntnisse aus Vergleichsberechnungen mit sog. erweiterten DIN 4126‐Ansätzen und 3D‐Simulationen mit FE‐Methoden hinsichtlich des Einflusses der Schlitzdicke auf die Nachweisführung von Eckschlitzen mitteilen. Die Grundsätze der Nachweisführung mit vereinfachten ebenen Ansätzen für die Eckschlitze wurden in [1] dargelegt. Aufgrund der Anregungen aus der Anwendung in der Praxis wurden Ergänzungen vorgenommen, um das Verfahren auch für relativ dicke Erdschlitze sinnvoll anwenden zu können.

On the stability of slurry corner trenches. The overall stability calculations of non planar open trenches used in the course of the D‐Wall construction is not covered by the existing regulations in Germany and even not an easy task. The present paper provides new findings arisen from 3D FE‐simulations and comparisons with analytical models based on extended model of the DIN 4126 in order to ascertain the influence of the width of non‐planar D‐Wall panels on the stability of the open trench. The basic ideas for the design calculations dealing with simplified models for non‐planar panels have been presented in [1] and due to the feed back from the application in practise some modifications of the simplified analysis have been carried out in order to facilitate the application of the model for large panel widths.
Bemessung von Monopiles für die Gründung von Offshore‐Windenergieanlagen
Authors: Achmus Martin
Published: September 2011

Monopiles sind die bevorzugte Gründungsvariante für Offshore‐Windenergieanlagen bei moderaten Wassertiefen. Hinsichtlich der Erfassung des Systemverhaltens im Rahmen der Bemessung bestehen jedoch einige Unsicherheiten bzw. offene Fragen. Zum einen stellt sich die Frage, ob die p‐y‐Methode als bislang übliches Berechnungsverfahren für Pfähle sehr großer Durchmesser angewandt werden kann, zum anderen ist unklar, wie von der Genehmigungsbehörde geforderte explizite Nachweise des Tragverhaltens unter zyklischen Lasten erbracht werden können. Im Aufsatz wird der Stand der Technik und des Wissens zur Bemessung und zum Tragverhalten von Monopiles dargestellt und diskutiert, und offene Fragen bzw. Forschungsbedarf werden aufgezeigt. Darauf aufbauend werden Konzepte zur praktischen Bemessung vorgestellt.

Design of monopile foundations for offshore wind energy converters – Concepts and open questions. Monopiles are the favorized variant of the foundation of offshore wind energy converters at moderate water depths. However, some open questions and uncertainties exist regarding the analysis of the behavior of a monopile foundation in the scope of the design. It is questionable whether the usually applied p‐y method is suitable for the calculation of the behavior of piles with very large diameter. Moreover, it is uncertain how explicit proofs of the monopile behavior under cyclic loads, which are required by the approving authority, can be carried out. In the paper at hand, the state of knowledge regarding behavior and design of monopiles is presented and discussed, and open questions and research needs are identified. Based on that, concepts for practical design are proposed.
Typisierte Stabtragwerke aus Holz in der DDR von 1955 bis 1990
Authors: Tasche Martin , Baumgarten Henrik , Zinnert Gunter
Published: September 2011

Der Aufsatz behandelt typisierte Stabtragwerke aus Holz, die in der DDR ab 1955 entwickelt wurden. Als Anwendungsgebiete galten überwiegend landwirtschaftliche Nutzbauten, aber auch Lagerhallen und Dächer von Schulen und anderen Gesellschaftsbauten. Nach Kenntnis der Autoren handelt es sich um den ersten Versuch, derartige typisierten DDR‐Tragkonstruktionen vergleichend darzustellen. Dieser Aufsatz schließt sich thematisch dem Aufsatz im Heft 8/2011 der BAUTECHNIK über typisierte stählerne Stabtragwerke in der DDR an.

Typified wooden frame structures in the GDR from 1955 until 1990. This article outlines typified wooden frame structures, which were developed in the former GDR from 1955 until 1990 primarily for farming facilities, but also for storage buildings and roofs of social buildings. From the level of the author’s awareness this is the first publication discussing typified structures of the GDR in a comparative way. This article completes the article published in the issue No. 8/2011 of BAUTECHNIK about typified steel frame structures in the GDR.
Korrosions‐ und Verbundverhalten verzinkter Betonstähle in Betonen mit chromatreduzierten Zementen
Authors: Ebell Gino , Burkert Andreas , Lehmann Jens , Mietz Jürgen
Published: September 2011

Durch die Absenkung des Chromatgehalts der Zemente verändern sich die elektrochemischen Reaktionen von verzinkten Betonstählen in der Frischbetonphase. Mit Hilfe von elektrochemischen Messungen sowie Stabauszugsversuchen wurde an chromathaltigen und chromatreduzierten Zementen die Auswirkung des Chromats auf die Deckschichtbildung am Zink und auf das Verbundverhalten untersucht.

Mit den Ergebnissen konnte eine Beeinträchtigung der Verbundzone als Folge der Chromatreduzierung für die Zementarten CEM I und CEM II nachgewiesen werden. Die Störung der Verbundzone ist in Bezug auf die sich ausbildende Porenstruktur als dauerhaft anzusehen. Die Auswirkungen auf das Verbundverhalten werden mit zunehmendem Betonalter weitgehend kompensiert. Die Ergebnisse der bezogenen Verbundspannung bei Verschiebewegen von 0,1 mm und 0,5 mm liegen trotz der Gefügestörung noch im Bereich der Erwartungswerte für den unverzinkten Betonstahl. Unter baupraktischen Gesichtspunkten muss die auftretende Gefügestörung hinsichtlich der Verbundspannung daher keine Berücksichtigung finden.

Corrosion and bond behaviour of galvanized reinforcing steels in concrete with chromate‐reduced cements

The reduction of the chromate contents in cements affects the electrochemical reactions of galvanized reinforcing steels in fresh concrete. By means of electrochemical measurements and bar pull‐out tests the effect of chromates on the formation of protective coatings at the zinc and the bond behaviour have been investigated using chromate‐containing and chromate‐reduced cements.

The results have shown that the bond zone was affected as a result of chromate reduction for cement types CEM I and CEM II. The disturbance to the bond zone should be considered as long‐term in relation to the pore structure which is formed. The effects on the bond are largely compensated for as the concrete ages. The results of the related bond strength with displacement paths of 0.1 and 0.5 mm, respectively, are still within the range of expected figures for non‐galvanized reinforcing steel despite the structural disturbance. Under practical aspects it is not necessary that the existing structural disturbance with respect to bond strength is taken into consideration.
Die Generalsanierung des Johann Joseph Fux Konservatoriums aus der Sicht der Tragwerksplanung
Authors: Zellinger Manfred , Mandl Peter
Published: September 2011

Bauen im Bestand nimmt in der Bauwirtschaft eine immer bedeutendere Rolle ein. Die Erhaltung und die Erneuerung von Bestandsbauten werden zukünftig eine steigende Anzahl zu realisierender Projekte mit sich bringen. Für den Tragwerksplaner ergibt sich eine Vielfalt von Fragestellungen, die es in interdisziplinärer Zusammenarbeit zwischen am Projekt beteiligten Fachplanern zu lösen gilt. Im vorliegenden Aufsatz wird die Generalsanierung des Johann Joseph Fux Konservatoriums in Graz aus der Sichtweise der Tragwerksplanung mit seinen statischkonstruktiven Besonderheiten dargestellt. Die Fertigstellung erfolgte nach einer Bauzeit von einem Jahr im August 2009.
Wartung bei Parkbauten – Inhalte und juristische Stellung
Authors: Bastert Heinrich , Krams Jürgen , Meyer Lars , Motzke Gerd
Published: September 2011

Gerissene Tragwerke aus Stahlbeton und Spannbeton, die korrosionsfördernden Einwirkungen durch Chloride auf die Bewehrung ausgesetzt sind, bedürfen gesonderter Schutzmaßnahmen, um ihre Standsicherheit und Dauerhaftigkeit und damit auch ihre Gebrauchstauglichkeit über den geplanten Nutzungszeitraum sicherzustellen. Insbesondere die befahrenen tragenden Bauteile in einem Parkbau unterliegen neben den korrosiven Randbedingungen zusätzlichen Verschleißbeanspruchungen, die einer regelmäßigen Wartung bedürfen. Die Wartung und die ihr vorausgehende fachkundige Inspektion sind integrale Bestandteile der Instandhaltung von Gebäuden und damit unverzichtbar bei einem modernen Gebäudemanagement. Anforderungen an die Inspektion und Wartung von Betonbauwerken sind in verschiedenen Regelwerken und Merkblättern formuliert, die fortlaufend an aktuelle Erfahrungen und technische Entwicklungen angepasst werden. Grundlage für eine fachgerechte Instandhaltung eines Gebäudes ist der Wartungsplan, der vom verantwortlichen Planer frühzeitig erstellt und mit seinem Auftraggeber abgestimmt werden muss. Der nachfolgende Aufsatz gibt einen Überblick über den aktuellen Stand der Anforderungen an einen Wartungsplan, die Umsetzungsmöglichkeiten und die rechtliche Betrachtungsweise.

Car Park Maintenance – Current Status of Recommendations

Chloride attack is a major deterioration factor for reinforced concrete structures. To ensure durability of cracked structural concrete especially in car parks with corrosion due to the ingress of chloride it is necessary to prevent further deterioration through repair work. This article presents the current status of recommendations for the inspection, maintenance, management, and contracting aspects of car park structures.
Dauerhaftigkeit von Betonbauteilen und Fundamenten unter durchlässigem Fahrbelag
Authors: Fingerloos Frank , Meier Andreas
Published: September 2011

Die Ausbildung von Parkflächen in Parkhäusern und Tiefgaragen direkt auf dem Baugrund kann auch mit nichttragenden Parkböden erfolgen, wenn die Gründung des Bauwerks auf unabhängigen Streifen‐ bzw. Einzelfundamenten möglich ist und kein drückendes Grundwasser ansteht. Diese Ausführungsart erfreut sich zunehmender Verbreitung, da die hohen Anforderungen aus der Expositionsklasse XD3 mit “zusätzlicher Maßnahme” nach Fußnote b) in Tabelle 3 der DIN 1045‐1 bzw. Tabelle 4.1 in DIN EN 1992‐1‐1 mit Nationalem Anhang dann für die befahrene Parkfläche nicht erforderlich sind. Zu diesen Parkböden gehören z. B. Pflasterbeläge aus Beton‐ oder Naturstein oder unbewehrte bzw. nur konstruktiv bewehrte Betonböden. Unabhängig davon ist jedoch die Dauerhaftigkeit der unterhalb der durchlässigen Parkflächen liegenden Fundamente und Bauteile sicherzustellen. Hierzu werden im Folgenden einige Hinweise gegeben.

Durability of concrete members and foundations under permeable parking surface

Non‐bearing parking floors in carparks may be realized directly on the ground, if the foundation of the structure is independent of this floor and no pressuring groundwater exists. This type of floor has been become more common, especially because the strict requirements due to exposure class XD3 with an “additional measure” according to table 3 in DIN 1045‐1 or table 4.1 in the German National Annex of DIN EN 1992‐1‐1 are not necessary for the used surface. Typical non‐bearing floor types are pavements of concrete or natural stone as well as unreinforced or only constructive reinforced floors. Independently, the durability of underlying foundations and members must be ensured. In the following text some comments are given to this topic.
A simple and flexible Holm gatekeeping procedure
Authors: Li Jianjun(David)
Published: September 2011

Major objectives of a clinical trial are commonly stated in a hierarchical order as primary and secondary. The parallel gatekeeping testing strategy provides an opportunity to assess secondary objectives when all or partial primary objectives are achieved. The current available gatekeeping procedures have different pros and cons so users either need to justify the assumption associated with some procedures or tolerate suboptimal power performance of other procedures. By applying the Holm test with a flexible alpha splitting technique, we propose a procedure which (1) is powerful for assessing the primary objectives, (2) can be used when no assumption can be made on the dependency structure of test statistics, and (3) has the full flexibility to allocate user‐preferred alpha to assess the secondary objectives based on the number of primary objectives achieved. A real clinical trial example is used for illustration of the proposed procedure.
Management of late postoperative complications of bariatric surgery
Authors: Hamdan K , Somers S , Chand M
Published: September 2011

Background

The prevalence of obesity is increasing worldwide and the past decade has witnessed an exponential rise in the number of bariatric operations performed. As a consequence, an increasing number of patients are presenting to non-specialist units with complications following bariatric procedures. This article outlines the management of the most common late postoperative complications that are likely to present to the general surgeon.

Methods

A search was conducted for late postoperative complications after bariatric surgery using PubMed, Embase, OVID and Google search engines, and combinations of the terms bariatric surgery, gastric bypass, gastric banding or sleeve gastrectomy, and late or delayed complications. Only studies with follow-up longer than 6 months were included.

Results

The most common long-term complications after gastric banding include band slippage and erosion. Deflation or removal of the band is often required. Internal hernia, adhesions and anastomotic stenosis are common causes of intestinal obstruction after gastric bypass surgery. Hepatobiliary complications pose a particular challenge because of the altered anatomy. Functional disorders such as reflux and dumping, and nutritional deficiencies are common and should be differentiated from conditions that require urgent investigations and timely surgical intervention.

Conclusion

The immediate management of bariatric patients presenting with complications outside the immediate postoperative period requires adherence to basic surgical principles. Accurate diagnosis often relies on high-quality contrast and cross-sectional imaging, and effective surgical intervention necessitates a broad understanding of the altered anatomy, advanced surgical skills and liaison with specialists in the field when necessary.
Cost–utility of bariatric surgery for morbid obesity in Finland
Authors: Mäklin S , Malmivaara A , Linna M , Victorzon M , Koivukangas V , Sintonen H
Published: September 2011

Background

The aim of this study was to evaluate the cost–utility of bariatric surgery (gastric bypass, sleeve gastrectomy and gastric banding) compared with ordinary treatment in the Finnish healthcare system.

Methods

Analysis was done from a healthcare provider's perspective using a combination of a decision tree and a Markov model, with a time horizon of 10 years. Health-related quality of life was estimated from a representative population survey, and other parameter values were based on registers, systematic reviews, controlled studies and expert opinion.

Results

In the base-case analysis, bariatric surgery was both more effective and less costly than the ordinary treatment. The mean costs were €33 870 and €50 495, and the mean number of quality-adjusted life-years 7·63 and 7·05, for bariatric surgery and ordinary treatment respectively. Uncertainty around the parameter values was tested comprehensively in sensitivity analyses, and the results were robust.

Conclusion

Surgery for morbid obesity increases health-related quality of life, and reduces the need for further treatments and total healthcare costs. According to this analysis, non-operative care would be more costly for the Finnish healthcare system on average after 5 years following surgery.
Highly Fluorescent 5‐(5,6‐Dimethoxybenzothiazol‐2‐yl)‐2′‐Deoxyuridine 5′‐Triphosphate as an Efficient Substrate for DNA Polymerases
Authors: Sato Kousuke , Sasaki Ayano , Matsuda Akira
Published: September 2011

We herein describe the synthesis of fluorescent 5‐(5,6‐dimethoxybenzothiazol‐2‐yl)‐2′‐deoxyuridine 5′‐triphosphate (dbtUTP) and primer extension reactions using dbtUTP. We also carried out primer extension reactions using the btU template. B family DNA polymerases, such as KOD, Deep Vent (exo‐), and 9°Nm DNA polymerases, were effective for elongation with dbtUTP. Deep Vent (exo‐) and KOD DNA polymerases have excellent fidelity for incorporating dbtUTP only at the site opposite the adenine template and only dATP when using the btU template. Therefore, dbtUTP is an excellent fluorescent nucleotide that can be incorporated into DNA by DNA polymerases.
Heavy Metal with a Heavy Impact: Olefin Dimerization Reactions in Triphenylbismuth Buffered Chloroaluminate Ionic Liquids
Authors: Dötterl Matthias , Alt Helmut G.
Published: September 2011

The addition of weak Lewis bases such as NPh3, PPh3, or BiPh3 (Ph=phenyl) to Lewis acidic chloroaluminate ionic liquids yielded efficient cocatalysts for nickel catalyst precursors in highly selective biphasic dimerization reactions of α‐olefins. Triphenylbismuth buffered systems were found to produce up to 96 % dimers from propene. Selectivities and activities were influenced by varying the compositions of the ionic liquids. Furthermore, buffer addition reduced the melting points of the resulting liquids. This effect allowed a screening of many different organic halide salts, which were found to strongly influence the lifetimes and selectivities of the corresponding biphasic olefin dimerization systems. An optimized system dimerized ethene, propene, 1‐butene, and 1‐hexene with high selectivities. It is even possible to recycle amines and buffers used for these compositions by a simple acid base extraction of the spent ionic liquid catalyst systems. We also proposed a mechanism for these NiII catalyzed selective olefin dimerization reactions in alkylaluminum free buffered chloroaluminate melts. The addition of small amounts of BiPh3 to an ionic liquid composition used in the commercial DIFASOL process increased the selectivity to give dimers from a biphasic propene dimerization reaction by 15 %.
Light‐Driven Uncoupling of Nitrogenase Catalysis from ATP Hydrolysis
Authors: Roth Lauren E. , Tezcan F. Akif
Published: September 2011

As the sole artificial means to catalyze the reduction of atmospheric N2 to NH3, the Haber–Bosch process carries an enormous industrial and agricultural importance. Yet, despite being developed nearly a century ago and its immense economic and environmental cost, no cleaner or more efficient alternative to this process has been found. Biological nitrogen fixation catalyzed by nitrogenase is an enticing place to look for inspiration for an alternative catalyst. However, this enzyme’s catalytic mechanism is poorly understood, because it relies upon ATP hydrolysis and protein interactions to coordinate electron transfer and substrate activation, creating a complex mixture of redox intermediates during turnover. Recently, new approaches have been presented to circumvent this problem. One such possibility is the use of covalently attached photosensitizers to directly transfer electrons to the active site of the enzyme, thereby uncoupling substrate reduction from ATP hydrolysis and allowing the population of discrete reaction intermediates for structural or spectroscopic investigation.
Structural Features and Hydrogen‐Bond Properties of Galanthamine and Codeine: An Experimental and Theoretical Study
Authors: Atkinson Alexandre P. , Baguet Evelyne , Galland Nicolas , Le Questel Jean‐Yves , Planchat Aurélien , Graton Jérôme
Published: September 2011

Structural features of galanthamine and codeine, two allosteric potentiating ligands of nicotinic acetylcholine receptors (nAChRs), have been investigated through experimental studies in solution by FTIR and NMR spectroscopy and by quantum chemical calculations in the isolated state. The infrared spectra accumulated in solvents of various polarities show that the intramolecular OH⋅⋅⋅O hydrogen bond in galanthamine is stronger than the corresponding interaction in codeine. Molecular electrostatic potential calculations allow rationalisation of the experimental trends. NOE measurements on the two ligands in the same solvent range show significant differences. In apolar solvents, the NMR spectroscopic data indicate the occurrence of CH⋅⋅⋅O hydrogen‐bond interactions, whereas in the more polar solvents, a trans orientation of the methoxy group with respect to the furanyl oxygen atom is favoured. A natural bond orbital (NBO) analysis provides evidence that these stabilising interactions originate in the hyperconjugation between the lone pairs of the furanyl oxygen atoms, n(O), and the methoxy antibonding σ*(CH) orbitals within the two molecules. Despite the strong structural similarities between the two allosteric modulators, FTIR equilibrium constants measurements of hydrogen‐bond complexation combined with quantum chemistry calculations point out the significant increase of hydrogen‐bond accepting strength of galanthamine relative to codeine. This increase is mainly assignable to the stronger hydrogen‐bond basicity of the hydroxyl group, and to a lesser extent to the higher hydrogen‐bond accepting strength of the amino nitrogen of galanthamine in comparison with the corresponding groups of codeine. An analysis of the interactions that occur between the two ligands and acetylcholine esterase (AChE) suggests significant differences with Trp84, a key component of the AChE catalytic active site. In contrast, both ligands appear to interact similarly with acetylcholine binding protein (AChBP).
Conjugated Asymmetric Donor‐Substituted 1,3,5‐Triazines: New Host Materials for Blue Phosphorescent Organic Light‐Emitting Diodes
Authors: An Zhong‐Fu , Chen Run‐Feng , Yin Jun , Xie Guo‐Hua , Shi Hui‐Fang , Tsuboi Taiju , Huang Wei
Published: September 2011

Conjugated asymmetric donor‐substituted 1,3,5‐triazines (ADTs) have been synthesized by nucleophilic substitution of organolithium catalyzed by [Pd(PPh3)4]. Theoretical and experimental investigations show that ADTs possess high solubility and thermostability, high fluorescent quantum yield (35 %), low HOMO (−6.0 eV) and LUMO (−2.8 eV), and high triplet energy (ET, 3.0 eV) according to the different substitution pattern of triazine. The application as host materials for blue PHOLEDs yielded a maximum current efficiency of 20.9 cd A−1, a maximum external quantum efficiency of 9.8 %, and a brightness of 9671 cd m−2 at 5.4 V, making ADTs good candidates for optoelectronic devices.
WaterLOGSY NMR Experiments in Conjunction with Molecular‐Dynamics Simulations Identify Immobilized Water Molecules That Bridge Peptide Mimic MDWNMHAA to Anticarbohydrate Antibody SYA/J6
Authors: Szczepina Monica G. , Bleile Dustin W. , Müllegger Johannes , Lewis Andrew R. , Pinto B. Mario
Published: September 2011

X‐ray crystallographic data of the carbohydrate mimic MDWNMHAA when bound to an anti‐Shigella flexneri Y mAb SYA/J6 indicate the immobilization of water molecules, that is, the presence of “bound” waters, in the active site. Water Ligand Observed via Gradient Spectroscopy (WaterLOGSY) was used in conjunction with saturation transfer difference (STD)‐NMR spectroscopy to probe the existence of immobilized water molecules in the complex of MDWNMHAA 1 bound to mAb SYA/J6. Molecular dynamics simulations using the ZymeCAD Molecular Dynamics platform were then used to specify the likely locations of these water molecules. Of note, those waters involved in providing complementarity between the peptide and mAb SYA/J6 remained throughout the course of the simulation. Together, the experimental and computational protocols have been used to identify the bound water molecules present in the antibody‐peptide complex.
Construction of Hydrogen‐Bonded Ternary Organic Crystals Derived from L‐Tartaric Acid and Their Application to Enantioseparation of Secondary Alcohols
Authors: Kodama Koichi , Sekine Eriko , Hirose Takuji
Published: September 2011

Ternary organic crystals consisting of an L‐tartaric acid‐derived dicarboxylic acid, a commercially available achiral diamine, and a chiral secondary alcohol have been developed and characterized by X‐ray crystallography. 1D, 2D, and 3D hydrogen‐bonded supramolecular networks were constructed, depending on the structure of the diamine used. Benzylic and aliphatic secondary alcohols were enantioselectively incorporated into the crystal and were successfully enantioseparated with up to 86 and 79 % enantiomeric excess (ee), respectively. Selective incorporation of one enantiomer of 2‐butanol, which is a small chiral aliphatic alcohol, was achieved by the cooperative effects of hydrogen bonds, CH⋅⋅⋅π interactions, and van der Waals interactions between the guest and host molecules, with the aid of two water molecules. The high host potential of the binary supramolecular system is mainly attributed to the skewed conformation of two rigid aromatic groups of tartaric acid derivatives, which prevents dense packing of the molecules and enhances the formation of multicomponent inclusion crystals.
Flocculation–Sedimentation Combined with Chemical Oxidation Process
Authors: Nieto Leopoldo Martínez , Hodaifa Gassan , Rodríguez Salvador , Giménez José A. , Ochando Javier
Published: September 2011

Flocculation and sedimentation of particles are essential to many environmental and industrial processes. Solid–liquid separation in olive‐oil mill wastewater treatment by means of Fenton system is the key to work continuously and maintain a constant outlet flow of clarified water at the end of the oxidation process. Natural sedimentation is not capable to eliminate the sludge formed. The efficiency of flocculation operation using different flocculants as QG‐2001, QG‐2002, DQGALFLOC‐130H, and Nalco‐77171 was investigated. The optimum dosage of each flocculant, 150, 2.5, 66, and 6 mg dm−3, respectively, was determined. The results revealed that the best flocculant was Nalco‐77171, which determined 13.5% v/v final sludge separation and 86.5% v/v final clarified water obtained. Kinetics of sludge removal in the transition zone was adjusted to power law, v/v0 = Ktε, where the exponent, ε, varied in the range 0.141–0.670.