bluuebunny/crossref_metadata_2025 huggingface dataset:
Schlag um Schlag. Physik des Ruderns
Authors: Schnur Axel
Published: September 2010

Der Rudersport hat eine Maximierung der Bootsgeschwindigkeit zum Ziel. Entscheidenden Einfluss auf den Vortrieb hat die am Ruderblatt erzeugte Kraft. Wesentlich ist auch die Relativbewegung der Ruderer im Boot. Bei der Ganzkörpersportart kommt es auf die Minimierung der Reibungsverluste an. Das gelingt durch möglichst gleichförmige Bewegungsmuster und durch die Anpassung des Sportgerätes. Der Vortrieb wird dabei durch angepasste Hebelverhältnisse und die Arbeit über scheinbar uneffektive Winkel gewährleistet. Die durch die Bootsform diktierte Rumpfgeschwindigkeit limitiert ihn letztlich.
Aufladung von Vulkanwolken und Staubstürmen
Authors: Pähtz Thomas
Published: September 2010

In vulkanischen Aschewolken und Sandstürmen beobachtet man häufig blitzartige Entladungen. Sie sind die Folge einer vorangegangenen Aufladung der Wolken. Ursache hierfür ist ein Ladungsaustausch zwischen den Partikeln, wenn diese miteinander kollidieren. Die genaue Ursache hierfür ist jedoch umstritten und Gegenstand intensiver Forschung. Mit Hilfe von Laborexperimenten und Computersimulationen ist es unserer Gruppe an der ETH Zürich gelungen, einen Mechanismus zu identifizieren, der die Aufladung von aufgewirbelten Teilchenwolken erklären kann.
Kondensation mit Laserlicht
Authors: Rohwetter Philipp , Stelmaszczyk Kamil , Wöste Ludger
Published: September 2010

Nebel‐ und Wolkentröpfchen oder Eiskristalle können sich aus atmosphärischem Wasserdampf nur an bereits vorhandenen Kondensationskeimen bilden. Unsere Gruppe von der Freien Universität Berlin konnte nun zusammen mit Kollegen aus der Schweiz und Frankreich im Rahmen des Teramobile‐Projekts demonstrieren, dass sich solche Kondensationskeime mit kurzen, intensiven Laserpulsen in feuchter Atmosphäre erzeugen lassen.
Hepatitis C virus‐induced oxidative stress and mitochondrial dysfunction: A focus on recent advances in proteomics
Authors: Simula Maria Paola , De Re Valli
Published: September 2010

The natural history of chronic hepatitis C virus (HCV) infection presents two major aspects. On one side, the illness is by itself benign, whereas, on the other side, epidemiological evidence clearly identifies chronic HCV infection as the principal cause of cirrhosis, hepatocellular carcinoma, and extrahepatic diseases, such as autoimmune type II mixed cryoglobulinemia and some B cell non‐Hodgkin's lymphomas. The mechanisms responsible for the progression of liver disease to severe liver injury are still poorly understood. Nonetheless, considerable biological data and studies from animal models suggest that oxidative stress contributes to steatohepatitis and that the increased generation of reactive oxygen and nitrogen species, together with the decreased antioxidant defense, promotes the development of hepatic and extrahepatic complications of HCV infection. The principal mechanisms causing oxidative stress in HCV‐positive subjects have only been partially elucidated and have identified chronic inflammation, iron overload, ER stress, and a direct activity of HCV proteins in increasing mitochondrial ROS production, as key events. This review summarizes current knowledge regarding mechanisms of HCV‐induced oxidative stress with its long‐term effects in the context of HCV‐related diseases, and includes a discussion of recent contributions from proteomics studies.
Power‐related compatibility and maximum electrical power output of a thermogenerator
Authors: Seifert W. , Zabrocki K. , Müller E. , Snyder G. J.
Published: September 2010

The compatibility approach enables the description of thermoelectric effects in terms of intensive state variables. Within the framework of a new optimization strategy based on self‐compatible thermoelectric elements,the consequences for the maximum electrical power output from a graded thermoelectric generator with fixed length are discussed. Unlike efficiency and coefficient of performance, no strict local criterion exists for maximum power.
Electron spin resonance from semiconductor–metal separated SWCNTs
Authors: Havlicek M. , Jantsch W. , Rümmeli M. , Schönfelder R. , Yanagi K. , Miyata Y. , Kataura H. , Simon F. , Peterlik H. , Kuzmany H.
Published: September 2010

Electron spin resonance in the X band is reported for fully metal–semiconductor separated SWCNTs. For the experiments samples were immersed in ethanol or wrapped into a teflon foil. The response from the metallic tubes exhibits a strong asymmetry in the line shape whereas the asymmetry for the semiconducting (SC) tubes is comparatively small. In both cases the line widths are unusual small, of the order of 4 G. Particular attention is paid to SC nanotubes which exhibit a much stronger signal as compared to the metallic tubes. The signal intensity is nearly Curie like with a small enhancement beyond $1/T$ in the low temperature range. The $1/T$ behavior renders the ESR response unobservable at 300 K. The finite value for the asymmetry parameter in the SC tubes is assumed to originate from charges picked up during exposure to air or to ethanol.
Photodehydrocyclizations of stilbene‐like compounds XV: Electronic overlap population as a reactivity measure in photocyclizations of pentahelicenes
Authors: Tinnemans A. H. A. , Laarhoven W. H. , Sharafi‐Ozeri S. , Muszkat K. A.
Published: September 2010

The reactivity of several pentahelicene derivatives with respect to photocyclization was shown to be directly related to the EH first excited state electronic overlap population of the atom pair involved in the cyclization, and also to the difference in electronic overlap populations of these atoms resulting from the electron excitation.

The lack of reactivity caused by benzo‐annelation on the 7,7′ atoms of pentahelicenes is attributed to an inversion of the normal MO sequence within the two topmost occupied orbitals and the two lowest unoccupied orbitals.
Electronic coupling in inter‐ and intramolecular donor‐acceptor systems as revealed by their solvent‐dependent charge‐transfer fluorescence
Authors: Verhoeven J. W. , Scherer T. , Wegewijs B. , Hermant R. M. , Jortner J. , Bixon M. , Depaemelaere S. , de Schryver F. C.
Published: September 2010

The solvent dependence of the radiative‐rate constant of both inter‐ and intramolecular donor‐acceptor systems reveals the occurrence of significant intensity borrowing from one or more local transitions. This phenomenon appears to be especially pronounced in systems of the type D‐3σ‐A, where donor and acceptor interact via through‐bond interaction over a relay of three σ bonds. Within the context of a three‐state model, involving the no‐bond state (DA), the charge transfer state (D+A−) and a single locally excited state [(DA)*], a simplified method is given to analyse the electronic coupling elements between these states.
Photochemistry of 2,5‐dimethyl‐1,3,5‐hexatrienes in argon matrices. Formation of isomers and rotamers
Authors: Brouwer A. M. , Jacobs H. J. C.
Published: September 2010

Irradiation of argon matrix‐isolated E‐2,5‐dimethyl‐1,3,5‐hexatriene results in the formation of thermodynamically less stable rotamers. In contrast, the corresponding Z‐triene readily undergoes light‐induced double bond isomerization to produce the E isomer. The cZc rotamer of Z‐2,5‐dimethylhexatriene is obtained by irradiation of 1,4‐dimethyl‐1,3‐cyclohexadiene. Characteristic features in the UV and IR absorption spectra of the various rotational and geometric isomers are discussed. Recent theoretical work has indicated that single and double bond isomerizations are both possible starting from the A excited state surface of E and Z‐hexatriene. Experimentally, we have found clear preferences for either of the two, depending on the initial geometry.
Neolignans, cyclohexanes and alkaloids from Piper wightii
Authors: Boll Per M. , Prasad Ashok K. , Tyagi Om D. , Wengel Jesper , Olsen Carl E. , Kumar Naresh , Bisht Kirpal S. , Parmar Virinder S.
Published: September 2010

Studies of the dichloromethane extract of stems and the methanolic extract of fruits of Piper wightii Miq. resulted in the isolation of 12 compounds, all new for this species. They comprise a novel neolignan 1, a neolignan new as a natural product 2, a novel cyclohexane 5, two known neolignans 3 and 4, one known cyclohexane 6, and six known alkaloids 7, 8, 9, 10, 11 and 12.
Easy preparation of enantiopure C2 symmetrical hydroxy and amino sulfides derived from ephedrine and their application in a Pd catalyzed coupling reaction
Authors: Koning Bartjan , Hulst Ron , Kellogg Richard M.
Published: September 2010

Ephedrine can be readily converted by means of intramolecular SN2 substitution by the hydroxyl or amino substituent into, respectively, the corresponding epoxide or aziridine with high stereocontrol. Subsequent stereoselective ring opening at the benzylic centre using tetrabutyl‐ammonium fluoride (TBAF) and dithiols affords the C2 symmetrical hydroxy or amino sulfides in excellent yield. Application of these ligands in a palladium‐catalyzed asymmetric allylic substitution reaction gave moderate to high enantiomeric excesses (up to 79%) and high yields of product.
Incorporation of fullerene‐C60 and C60 adducts in micellar and vesicular supramolecular assemblies; introductory flash photolysis and photoredox experiments in micelles
Authors: Williams René M. , Verhoeven Jan W. , Crielaard Wim , Hellingwerf Klaas J.
Published: September 2010

The incorporation of fullerene‐C60 and of C60 adducts into Triton X‐100 (TX100) micelles and into liposomes made of phosphatidyl‐ethanolamine from Escherichia coli has been studied. Incorporation curves and UV‐Vis absorption spectra for the liposomes are presented. Flash photolysis experiments in TX100 micelles in the presence of the electron donors N,N,N′,N′‐tetramethyl‐p‐phenylenediamine (TMPD) and cytochrome c resulted in the observation of oxidized transient species.
Effect of cyclopentenone annelation on a cycloheptatriene ‐ norcaradiene equilibrium
Authors: Oda Mitsunori , Horiguchi Hidemasa , Masaki Yoshimi , Sakamoto Yukinari , Kuroda Shigeyasu
Published: September 2010

Dihydroazulenones 5 and 6 were prepared by photochemical isomerisation from their isomers 7 and 8, respectively. 5 and 6 were found to be substantially in equilibrium with the norcaradiene forms, although isomers 7 and 8 exist as the cycloheptatriene forms.
Structural revision of the cycloadduct of bicyclo[5.3.0]deca‐1(7),2,4‐triene‐10‐one with 4‐phenyl‐1,2,4‐triazoline‐3, 5‐dione
Authors: Oda Mitsunori , Horiguchi Hidemasa , Kajioka Takanori , Kuroda Shigeyasu
Published: September 2010

Cycloaddition reaction of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione(PTAD) to bicyclo[5.3.0]‐deca‐1(7),2,4‐trien‐10‐one (3) was reinvestigated. In various conditions, the reaction afforded solely 1:1 cycloadduct as reported. The structure of this adduct, previously thought to be a formal [6+2] adduct, was revised. This adduct is now thought to be a cycloheptatriene‐derived [4+2] adduct on the basis of extensive 1H‐ and 13C‐NMR studies.
The synthesis of liquid‐crystalline diacrylates derived from cyclohexane units
Authors: Lub J. , van der Veen J.H. , ten Hoeve W.
Published: September 2010

Ordered polymeric networks are produced via the photopolymerization of liquid‐crystalline (LC) diacrylates. When these diacrylates are derived from aromatic rings, the networks show UV‐light instability. In order to overcome this problem, the cyclohexane analogues of two of these LC diacrylates were synthesized. The newly formed molecules exhibit much lower UV absorption than their aromatic analogues but also completely different phase behaviour. One of them showed a highly viscous LC phase, the other lacks LC properties.
Interaction of alkali metals with unsaturated heterocyclic compounds. The reductive metallation of 2,3,5,6‐tetraphenylpyrazine and the synthesis of 1,2‐dihydro‐1,4‐diazine derivatives
Authors: Kaban Şeniz , Öcal Nüket
Published: September 2010

Treatment of 2,3,5,6‐tetraphenylpyrazine (1) with sodium in tetrahydrofuran effected the formation of monomeric dianion 2. The chemical behaviour of this new disodium adduct was characterized by a variety of reagents. Generally, the protonation (water), alkylation (methyl iodide and benzyl chloride), and acylation (methyl and ethyl chloroformate) products were 1,2‐dihydrotetraphenyldiazine derivatives. An annulation of the pyrazine ring system was accomplished by treating the dianion with polymethylene chlorides, Cl(CH2)nCl, n = 2, 3, 4.
Lewis‐acid catalysis of carbon carbon bond forming reactions in water
Authors: Engberts Jan B. F. N. , Feringa Ben L. , Keller Erik , Otto Sijbren
Published: September 2010

In this article, we review the recent progress that has been made in the field of Lewis‐acid catalysis of carbon carbon‐bond‐forming reactions in aqueous solution. Since water hampers the hard hard interactions between the catalyst and the reactant, it often complicates catalysis. However, once coordination has taken place, water can have beneficial effects on rates and selectivities of Lewis acid catalysed Diels Alder reactions, aldol reactions, allylation reactions, Barbier and Mannich type reactions as well as Michael additions.
Development of a mechanistic picture of the hydrodemetallization reaction of metallo‐tetraphenylporphyrin on a molecular level
Authors: Janssens J.P. , Elst G. , Schrikkema E.G. , van Langeveld A.D. , Sie S.T. , Moulijn J.A.
Published: September 2010

Vanadyl‐ and nickel‐tetraphenylporphyrins (VO‐TPP and Ni‐TPP) have often been used as model compounds for the metallo‐porphyrin (‐like) fraction in heavy oil residua. The goal of the present work was to validate and to extend the present‐known reaction mechanism for the hydrodemetallization (HDM) of metallo‐tetraphenylporphyrins (M‐TPP). Based on molecular‐modelling calculations and GC‐MS analysis, new reaction intermediates could be identified and an extended reaction mechanism for the hydrodemetallization of metallo‐TPP proposed. The mechanism proceeds via three hydrogenation steps on β‐pyrrole positions of the porphyrinic structure to a meso‐bridge‐hydrogenated structure. After an acid attack, ring opening, and a possible elimination of a tolyl group, the final product before metal removal is an open‐chain molecule. Metal removal and further conversion leads to monopyrrole‐containing molecules and metal deposition on the catalyst surface.
Synthesis and Superior Optical‐Limiting Properties of Fluorene‐Thiophene‐Benzothiadazole Polymer‐Functionalized Graphene Sheets
Authors: Midya Anupam , Mamidala Venkatesh , Yang Jia‐Xiang , Ang Priscilla Kai Lian , Chen Zhi‐Kuan , Ji Wei , Loh Kian Ping
Published: September 2010

A polymer based on fluorene, thiophene, and benzothiadazole as the donor–spacer–acceptor triad is covalently coupled to reduced graphene oxide (rGO) sheets via diazonium coupling with phenyl bromide, followed by Suzuki coupling. These polymer–graphene hybrids show good solubility in organic solvents, such as chloroform, tetrahydrofuran (THF), toluene, dichlorobenzene, and N,N‐dimethylformamide (DMF), and exhibit an excellent optical‐limiting effect with a 532‐nm laser beam. The optical‐limiting threshold energy values (0.93 J cm−2 for G–polymer 1 and 1.12 J cm−2 for G–polymer 2) of these G–polymer hybrids are better than that of carbon nanotubes (3.6 J cm−2).
A framework for automatic generation of security controller
Authors: Martinelli Fabio , Matteucci Ilaria
Published: September 2010

This paper concerns the study, the development and the synthesis of mechanisms for guaranteeing the security of complex systems, i.e. systems composed of several interacting components. A complex system under analysis is described as an open system, i.e. a system in which an unspecified component (a component whose behaviour is not fixed in advance) interacts with the known part of the system. Within this formal approach, we propose techniques that aim at synthesize controller programs able to guarantee that, for all possible behaviours of the unspecified component, the system should work properly, e.g. it should be able to satisfy a certain property. For performing this task, we first need to identify the set of necessary and sufficient conditions that the unspecified component has to satisfy in order to ensure that the whole system is secure. Hence, by exploiting the satisfiability procedures for temporal logic, we automatically synthesize an appropriate controller program that forces the unspecified component to meet these conditions. This will ensure the security of the whole system. In particular, we contribute within the area of the enforcement of security properties by proposing a flexible and automated framework that goes beyond the definition of how a system should behave to work properly. Indeed, while the majority of the related work focuses on the definition of monitoring mechanisms, we also address the synthesis problem. Moreover, we describe a tool for the synthesis of secure systems which is able to generate appropriate controller programs. This tool is also able to translate the synthesized controller programs into the ConSpec language. ConSpec programs can be actually deployed for enforcing security policies on mobile Java applications by using the run‐time framework developed in the ambit of the European Project S3MS. Copyright © 2010 John Wiley & Sons, Ltd.
A vector set for systematic metabolic engineering in Saccharomyces cerevisiae
Authors: Fang Fang , Salmon Kirsty , Shen Michael W. Y. , Aeling Kimberly A. , Ito Elaine , Irwin Becky , Tran Uyen Phuong C. , Hatfield G. Wesley , Da Silva Nancy A. , Sandmeyer Suzanne
Published: September 2010

A set of shuttle vectors was constructed to facilitate expression of genes for metabolic engineering in Saccharomyces cerevisiae. Selectable markers include the URA3, TRP1, MET15, LEU2‐d8, HIS3 and CAN1 genes. Differential expression of genes can be achieved as each marker is available on both CEN/ARS‐ and 2 µ‐containing plasmids. Unique restriction sites downstream of TEF1, PGK1 or HXT7‐391 promoters and upstream of the CYC1 terminator allow insertion of open‐reading frame cassettes for expression. Furthermore, a fragment appropriate for integration into the genome via homologous recombination can be readily generated in a polymerase chain reaction. Vector marker genes are flanked by loxP recognition sites for the CreA recombinase to allow efficient site‐specific marker deletion and recycling. Expression and copy number were characterized for representative high‐ and low‐copy vectors carrying the different marker and promoter sequences. Metabolic engineering typically requires the stable introduction of multiple genes and genomic integration is often preferred. This requires an expanded number of stable expression sites relative to standard gene expression studies. This study demonstrated the practicality of polymerase chain reaction amplification of an expression cassette and genetic marker, and subsequent replacement of endogenous retrotransposons by homologous recombination with flanking sequences. Such reporters were expressed comparably to those inserted at standard integration loci. This expands the number of available characterized integration sites and demonstrates that such sites provide a virtually inexhaustible pool of integration targets for stable expression of multiple genes. Together these vectors and expression loci will facilitate combinatorial gene expression for metabolic engineering. Copyright © 2010 John Wiley & Sons, Ltd.
Über einige Nebenprodukte bei der thermischen Isomerisierung von Dikalium‐o‐phthalat
Authors: Nelles J. , Streicher R.
Published: September 2010

Terephthalsäure kann nach Raecke durch thermische Isomerisierung des Dikaliumsalzes der o‐Phthalsäure gewonnen werden. Die drucklose Durchführung dieser Reaktion in einem kontinuierlich arbeitenden Stahlbandofen im Rahmen einer Pilot‐Anlage ermöglichte die Anreicherung von Nebenprodukten. Die Isolierung der Nebenprodukte Diphenyl, Terphenyl, Fluoren, Fluorenon und 9‐Phenyl‐fluoren wird beschrieben und der Bildungsmechanismus diskutiert.
Über die Reaktionsfähigkeit von Organo‐Silicium‐Verbindungen
Authors: Schott Günther
Published: September 2010

An Modellsubstanzen X–R–Y wird die Wirkung eines Substituenten X über ein Zwischenglied R auf das Reaktionszentrum Y untersucht. Dabei werden Substanzen verglichen, in denen ein C‐ bzw. ein Si‐Atom als Reaktionszentrum fungiert. Es wird geprüft, inwieweit die vorwiegend aus der Chemie der Kohlenstoffverbindungen bekannten Substituentenkonstanten σ (Hammett) und σ* (Taft) auf Organo‐Silicium‐Verbindungen anwendbar sind. Die gefundenen Abweichungen werden diskutiert.
Geochemische Prozesse durch tribomechanische Anregung
Authors: Thießen Peter Adolf , Heinicke Gerhard , Hennig Hans‐Peter
Published: September 2010

Seit Bestehen der Erde haben geochemische Prozesse die Bedingungen auf unserem Planeten grundlegend geändert. Neben den bisher für diese Veränderungen diskutierten Energiequellen wurde die mechanische Energie als weitere Möglichkeit zur Auslösung geochemischer Prozesse erkannt. Die mechanische Energie wird außer in der Erdkruste auch in Form exogener Kräfte wirksam.

Unter simulierten geochemischen Bedingungen wurde besonders die Tribochemie des Kohlenstoffs untersucht, da diese für die Entstehung des Lebens, die Genese von Erdgas und Erdöl sowie für Inkohlungsprozesse eine große Rolle spielt. Es konnte bewiesen werden, daß die am Kohlenstoff bzw. an Carbiden abgelaufenen Prozesse auf der Erde unter Laboratoriumsbedingungen auch bei tribomechanischer Anregung stattfinden. Besonders ist zu erwähnen, daß wichtige Vorstufen für die Herausbildung lebender Materie, das Acetylen, der Cyanwasserstoff und Aminosäuren, isoliert werden konnten. Es wird angenommen, daß auch heute noch tribochemische Reaktionen bei geochemischen Prozessen wirksam werden.
Das Verhalten von metallischen Hydrierkatalysatoren unter Einwirkung mechanischer Energie
Authors: Heinicke Gerhard , Lischke Ingeborg
Published: September 2010

Es wird eine Übersicht über die Entwicklungstendenzen der Tribokatalyse gegeben. Durch tribomechanische Bearbeitung wird die katalytische Aktivität von Hydrierkatalysatoren gegenüber einem unbearbeiteten Katalysator bedeutend, oft um mehrere Größenordnungen, erhöht. Während der Bearbeitung erreichen die Werte für die spezifische katalytische Aktivität ein Maximum und liegen um zwei Größenordnungen höher als die Werte, die an hochaktiven, durch Reduktion hergestellten Katalysatoren gemessen wurden. Parallel mit der Erhöhung der spezifischen Aktivität wird die Aktivierungsenergie der katalytischen Reaktion erniedrigt. Als Ursache der Veränderung der katalytischen Eigenschaften durch tribomechanische Bearbeitung wird der sog. „tribochemische Frischflächeneffekt”︁ angeführt. Durch den mechanischen Eingriff werden nicht nur metallische Frischflächen erzeugt, sondern auch Veränderungen im Bedeckungsverhältnis der Substratkomponenten erhalten.

Unter Bearbeitung wird die Vergiftungsempfindlichkeit von Katalysatoren wesentlich zurückgedrängt. Eine Regenerierung vergifteter Katalysatoren ist durch tribomechanische Beanspruchung möglich.

Auf die technische Bedeutung tribokatalytischer Reaktionen bei Reibungs‐, Schmierungs‐ und Verschleißvorgängen und bei Fließprozessen in der chemischen Verfahrenstechnik wird hingewiesen.
Neue Polykondensationsreaktionen zur Synthese von Polymeren mit Halbleitereigenschaften
Authors: Hörhold Hans‐Heinrich
Published: September 2010

Es wird über kondensierende Polyreaktionen zur Synthese von unsubstituierten und substituierten Poly‐p(m)‐xylylidenen und über einige ihrer Eigenschaften zusammenfassend berichtet. Poly‐p‐xylylidene sind hochohmige Halbleiter, die einen inneren Photoeffekt aufweisen. Es werden Zusammenhänge zwischen Struktur, Absorptionsspektrum, Photoleitfähigkeitsspektrum und elektrischer Dunkelleitfähigkeit aufgezeigt.

Mit N, N′‐Disulfinyl‐diaminoaromaten sind durch neue Polykondensationsreaktionen aromatische Polyazomethine und photoleitende Polyarylenschwefeldiimide synthetisiert worden.
Die rotierende Scheibenelektrode mit Ring und ihre Anwendungsmöglichkeiten
Authors: Müller Lothar
Published: September 2010

In dieser Übersicht werden die wichtigsten Arbeiten über die Anwendung der RSR zur Aufklärung komplexer elektrochemischer Reaktionen, zur Bestimmung der Geschwindigkeitskonstanten homogener Folgereaktionen bei EC‐, ECE‐ und katalytischen Prozessen und zur Untersuchung von Adsorptionsreaktionen zusammenfassend diskutiert. Aus dieser Darstellung ergibt sich, daß die Anwendung der RSR eine sehr wichtige Methode zur Aufklärung elektrochemischer Reaktionsmechanismen ist. Ihre große Bedeutung für die Untersuchung elektrochemisch‐organischer Reaktionen wird sich noch erhöhen, wenn man die elektrochemische Untersuchung von Zwischenprodukten mit der RSR mit Methoden zur Aufklärung ihrer chemischen Natur, wie ESR [54] oder Scheibenelektrode mit optischem Ring [55], koppelt.
Anwendung ternärer Komplexe zur photometrischen Analyse anorganischer Stoffe
Authors: Koch Siegfried , Ackermann Gerhard
Published: September 2010

Ausgehend von den Grenzen der üblichen photometrischen Analysenverfahren auf der Grundlage binärer Metallkomplexe werden Möglichkeiten zur Steigerung der Empfindlichkeit und der Selektivität analytischer Reaktionen auf der Basis von Gemischt‐Ligand‐Komplexen diskutiert. Berücksichtigung finden dabei sowohl Reaktionen in wäßriger Lösung als auch Verteilungsreaktionen in Gegenwart organischer Lösungsmittel. Nach der Besprechung einiger Besonderheiten bei der Anwendung ternärer Chelate in der photometrischen Analyse wird auf die Einhaltung optimaler Analysenbedingungen hingewiesen. Es wird gezeigt, daß zur Festlegung der besten Bedingungen Untersuchungen des Systems M, L, L' unumgänglich notwendig sind. Möglichkeiten dazu werden auf der Grundlage photometrischer Messungen aufgezeigt und die dabei zu beachtenden Kriterien mitgeteilt.
Zur CH‐ und C2‐Emission von Kohlenstoffverbindungen in Wasserstoffflammen
Authors: Henrion Günter , Marquardt Dieter , Raguse Hans‐Otto , Fabian Inge
Published: September 2010

3. Zusammenfassung

Für eine Reihe organischer Verbindungen (Alkohole, Alkane, Ester Ether, Ketone u.a.) konnte trotz ihrer strukturellen Unterschiede unter geeigneten Bedingungen der Flammenstöchiometrie (wasserstoffreich) eine Korrelation der Emissionsintensitäten von CH und C2 nahe r = 1 nachgewiesen werden.

Korrekturformeln zur Berücksichtigung von Sauerstoff und Doppelbindungen ermöglichen Darstellung der molaren Intensitäten als lineare Funktion der Kohlenstoffanzahl.
Mesogene β‐Estradiolanaloge
Authors: Hoffmann Siegfried , Brandt Walter , Kumpf Walter , Jaenecke Günter , Weißflog Wolfgang , Brezesinski Gerald
Published: September 2010

For elucidation of mesogenic facilities of steroid hormones, different series of coil‐like thermotropic β‐estradiols and some of their rod‐like artificial diethylstilbestrol analogues have been synthesized. The statics and dynamics of these simple thermotropics might primitively model bioregulatory operation modes of their hormonal standards.
Synthese und Eigenschaften der s‐Triazolo[1,5‐a]pyrimidine
Authors: Fischer Gunther
Published: September 2010

s‐Triazolo[1,5‐a]pyrimidines are important stabilizers for photographic silver halide emulsions and are used for pharmaceutical and agrochemical purposes, too. In the report it is dealt with syntheses from s‐triazoles and from pyrimidines, physical properties, tautomerism, nuclear alkylation, electrophilic and nucleophilic substitution, ring fission and other reactions, and applications.
Acceptability and Digestibility of Emulsions in a Rat Model: Effects of Solid Fat Content and Lipid Type
Authors: Wang Ying , Corwin Rebecca , Jaramillo D. Pamela , Wojnicki Francis J. , Coupland John N.
Published: September 2010

The present study sought to determine if alterations in the chemical nature and form of fat in food would reduce digestibility while maintaining acceptability in rats. Oil‐in‐water emulsions (d < 1 μm) were prepared with either liquid palm oil, solid hydrogenated palm oil or solid docosane, all stabilized with sodium caseinate. The emulsions were incorporated into a fat‐free rodent feed, and each offered over 5 days to separate cohorts of 12 male Sprague–Dawley rats housed in metabolic cages. The feed formulated with solid hydrogenated palm oil was significantly less acceptable than the feeds containing either liquid palm oil or docosane (feed intake 4.9, 26.6 and 32.1 g/animal/day respectively). The proportion of the fat retained (i.e. absorbed) was significantly less in the animals consuming the feed formulated with solid docosane than in the animals consuming either the liquid or solid palm oil (retention 8.7, 99.6, and 97.2%, respectively). The appearance of the feces from the rats fed docosane was different from the rats fed the triacylglycerol samples and thermal analysis revealed many of the solid alkane droplets had not coalesced during passage through the rat's digestive system. These results indicate that indigestible fats can be packaged into food in a manner that does not compromise the acceptability of the product, and does not produce any apparent intestinal distress.
Smoking Patterns among Jordanian Health Professionals: A Study about the Impediments to Tobacco Control in Jordan
Authors: Shishani Kawkab , Nawafleh Hani , Jarrah Samiha , Froelicher Erika Sivarajan
Published: September 2010

Background: Little is known about Arab health professionals' smoking practices.

Aim: This is the first study to examine smoking practices among Arab health professionals.

Methods: Background: Little is known about Arab nurses and physicians' smoking patterns.

Aim: This study aims to examine smoking patterns among Arab nurses and physicians.

Methods: A total of 918 nurses and physicians participated in this study. Data were collected using the Global Professional Health Survey.

Results: About 38.8% are current smokers. The smoking percentages for male nurses and male physicians were high (83.8%, 94.6% respectively) compared to female nurses and female physicians (16.2%, 5.4% respectively). Approximately 53.8% wanted to quit and 60.6% had made previous quit attempts that lasted for more than two days. About 64.1% believed that nurses and physicians who smoke were less likely to advise patients to stop smoking. The predictors of smoking were: age when tried first cigarettes OR=6.36, 95% CI=4.48, 9.04; father smokes OR=1.95, 95% CI=1.40, 2.72; mother smokes OR=1.99, 95% CI=1.18, 3.39; shift work OR=1.45, 95% CI=1.04, 2.03; and the interaction (gender and profession) OR=1.82, 95% CI=1.55, 2.14.

Discussion: Effective interventions often begin with and/or depend on nurses and physicians being committed to smoking cessation. Given the very high smoking rates among nurses and physicians a key priority must be to provide quit smoking programs and to enable them to become effective champions of smoking cessation nationwide.
Harmonisation of Category-III Precision Approach Navigation System Performance Requirements
Authors: Schuster Wolfgang , Ochieng Washington
Published: September 2010

Two distinct methods have been proposed and used to derive the required performance for CAT-II and III precision approaches: the “ILS (Instrument Landing System) Look-Alike Method” and the “Autoland Method”. The former is based on the concept of matching the performance of the ILS at the Navigation System Error (NSE) level through linearization of current specifications at a given height. The latter is based on the need to protect the safety of a landing operation using the current specification for the probability to land in a given landing box. Fundamentally, both methods assume the same safety targets and type of distribution, and are independent of specific navigation architectures. Therefore, they should deliver the same performance requirements. However, the requirements from the two methods for CAT-III approach are different. This paper reviews the two methods in detail, highlighting the key differences, and proposes ways to reconcile the methods and the requirements.
Characteristics of ground‐level enhancement–associated solar flares, coronal mass ejections, and solar energetic particles
Authors: Firoz K. A. , Cho K.‐S. , Hwang J. , Phani Kumar D. V. , Lee J. J. , Oh S. Y. , Kaushik Subhash C. , Kudela Karel , Rybanský Milan , Dorman Lev I.
Published: September 2010

Ground‐level enhancements (GLEs) are sudden, sharp, and short‐lived increases in cosmic ray intensities registered by neutron monitors. These enhancements are known to take place during powerful solar eruptions. In the present investigation, the cosmic ray intensities registered by the Oulu neutron monitor have been studied for the period between January 1979 and July 2009. Over this span of time, increase rates of 32 GLEs have been deduced. In addition, we have studied characteristics of the 32 event‐associated solar flares, coronal mass ejections (CMEs), and solar energetic particle (SEP) fluxes. We found that all of the 32 GLEs were associated with solar flares, CMEs, and SEP fluxes. Approximately 82% of the events were associated with X‐class flares. Most of the flares that were associated with GLEs of increase rates >10% originated from the active regions located on the southwest hemisphere of the Sun. The average speed (1726.17 km/s) of GLE‐associated CMEs was much faster than the average speed (423.39 km/s) of non‐GLE‐associated CMEs. It also became evident that ∼67% GLEs were associated with very fast (>1500 km/s) CMEs. Although a GLE event is often associated with a fast CME, this alone does not necessarily cause the enhancement. Solar flares with strong optical signatures may sometimes cause GLE. High SEP fluxes often seem to be responsible for causing GLEs as the correlation with SEP fluxes implies.
Pore fluid pressure and internal kinematics of gravitational laboratory air‐particle flows: Insights into the emplacement dynamics of pyroclastic flows
Authors: Roche O. , Montserrat S. , Niño Y. , Tamburrino A.
Published: September 2010

The emplacement dynamics of pyroclastic flows were investigated through noninvasive measurements of the pore fluid pressure in laboratory air‐particle flows generated from the release of fluidized and nonfluidized granular columns. Analyses of high‐speed videos allowed for correlation of the pressure signal with the flow structure. The flows consisted of a sliding head that caused underpressure relative to the ambient, followed by a body that generated overpressure and at the base of which a deposit aggraded. For initially fluidized flows, overpressure in the body derived from advection of the pore pressure generated in the initial column and decreased by diffusion during propagation. Relatively slow diffusion caused the pore pressure in the thinner flow to be larger than lithostatic at early stages. Furthermore, partial auto‐fluidization, revealed in initially nonfluidized flows, also occurred and contributed to maintain high pore pressure, whereas dilation or contraction of the air‐particle mixture with associated drag and/or pore volume variation transiently led the pressure to decrease or increase, respectively. The combination of all these processes resulted in long‐lived high pore fluid pressure in the body of the flows during most of their emplacement. In the case of the initially fluidized and slightly expanded (∼3–4%) flows, (at least) ∼70%–100% of the weight of the particles was supported by pore pressure, which is consistent with their inertial fluid‐like behavior. Dense pyroclastic flows on subhorizontal slopes are expected to propagate as inertial fluidized gas‐particle mixtures consisting of a sliding head, possibly entraining basement‐derived clasts, and of a gradually depositing body.
Strain dependent defect mediated ferromagnetism in Mn-doped and undoped ZnO thin films
Authors: Schoofs Frank , Fix Thomas , Hakimi Ali M. H. R. , Dhesi Sarnjeet S. , van der Laan Gerrit , Cavill Stuart A. , Langridge Sean , MacManus-Driscoll Judith L. , Blamire Mark G.
Published: September 2010

The structural and magnetic properties of pulsed laser deposited zinc oxide thin films have been investigated. Room temperature ferromagnetism is present in undoped as well as Mn-doped films. The saturation magnetization of the thin films reveals a dependence on both the composition and the out of plane lattice parameter. X-ray magnetic circular dichroism down to 2 K reveals a purely paramagnetic contribution from the Mn in Mn:ZnO films. We conclude that the observed ferromagnetism arises entirely from intrinsic defects in the ZnO which can be varied by manipulation of the lattice parameter.
Room temperature imaging at 1.63 and 2.54 THz with field effect transistor detectors
Authors: Nadar S. , Videlier H. , Coquillat D. , Teppe F. , Sakowicz M. , Dyakonova N. , Knap W. , Seliuta D. , Kašalynas I. , Valušis G.
Published: September 2010

GaAs nanometric field effect-transistors are used for room temperature single-pixel imaging using radiation frequencies above 1 THz. Images obtained in transmission mode at 1.63 THz are recorded using transistors operating in a photovoltaic mode with spatial resolution of 300 μm and voltage sensitivity of about 8 mV/W. A reduction in response with increasing frequency was observed and mitigated by the application of a source-drain current, leading to the demonstration of imaging at up to 2.54 THz.
Effect of hydrogen on catalyst nanoparticles in carbon nanotube growth
Authors: Behr Michael J. , Gaulding E. Ashley , Mkhoyan K. Andre , Aydil Eray S.
Published: September 2010

The structures of carbon nanotubes grown from catalytic nanoparticles via plasma-enhanced chemical vapor deposition in CH4/H2 mixtures show a strong dependence on the H2-to-CH4 ratio in the feed gas. A suite of characterization techniques, including optical emission, infrared, and Raman spectroscopies combined with convergent-beam and selected-area electron diffraction, and high-resolution (scanning) transmission electron microscopy imaging were used to systematically investigate the interrelation among plasma gas phase composition, catalysts morphology, catalyst structure, and carbon nanotube structure. Hydrogen plays a critical role in determining the final carbon nanotube structure through its effect on the catalyst crystal structure and morphology. At low H2-to-CH4 ratios (∼1), iron catalyst nanoparticles are converted to Fe3C and well-graphitized nanotubes grow from elongated Fe3C crystals. High (>5) H2-to-CH4 ratios in the feed gas result in high hydrogen concentrations in the plasma and strongly reducing conditions, which prevents conversion of Fe to Fe3C. In the latter case, poorly-graphitized nanofibers grow from ductile bcc iron nanocrystals that are easily deformed into tapered nanocrystals that yield nanotubes with thick walls.
An “adiabatic-hindered-rotor” treatment allows para-H2 to be treated as if it were spherical
Authors: Li Hui , Roy Pierre-Nicholas , Le Roy Robert J.
Published: September 2010

In para-H2–{molecule} interactions, the common assumption that para-H2 may be treated as a spherical particle is often substantially in error. For example, quantum mechanical eigenvalues on a full four-dimensional (4D) potential energy surface for para H2–{linear molecule} species often differ substantially from those calculated from the corresponding two-dimensional (2D) surface obtained by performing a simple spherical average over the relative orientations of the H2 moiety. However, use of an “adiabatic-hindered-rotor” approximation can yield an effective 2D surface whose spectroscopic properties are an order of magnitude closer to those yielded by a full 4D treatment.
Fabry–Pérot interferometer utilized for displacement measurement in a large measuring range
Authors: Wang Yung-Cheng , Shyu Lih-Horng , Chang Chung-Ping
Published: September 2010

The optical configuration of a Fabry–Pérot interferometer is uncomplicated. This has already been applied in different measurement systems. For the displacement measurement with the Fabry–Pérot interferometer, the result is significantly influenced by the tilt angles of the measurement mirror in the interferometer. Hence, only for the rather small measuring range, the Fabry–Pérot interferometer is available. The goal of this investigation is to enhance the measuring range of Fabry–Pérot interferometer by compensating the tilt angles. To verify the measuring characteristic of the self-developed Fabry–Pérot interferometer, some comparison measurements with a reference standard have been performed. The maximum deviation of comparison experiments is less than 0.3 μm in the traveling range of 30 mm. The experimental results show that the Fabry–Pérot interferometer is highly stable, insensitive to environment effects, and can meet the measuring requirement of the submicrometer order.
Enhanced spin signals due to native oxide formation in Ni80Fe20/Ag lateral spin valves
Authors: Mihajlović Goran , Schreiber Daniel K. , Liu Yuzi , Pearson John E. , Bader Samuel D. , Petford-Long Amanda K. , Hoffmann Axel
Published: September 2010

Large nonlocal spin valve signals are reported in mesoscopic Ni80Fe20/Ag lateral spin valves upon exposing them to air. Magnetotransport measurements combined with transmission electron microscopy show that the formation of a native oxide layer at the Ni80Fe20/Ag interface is responsible for the large signals. The results indicate that lateral spin valves with superior performance to those based on high-resistance tunnel barriers can be achieved via controllable growth of native permalloy oxides.
Demixing of a binary symmetric mixture studied with transition path sampling
Authors: Schöll-Paschinger Elisabeth , Dellago Christoph
Published: September 2010

We present transition path sampling simulations of the nucleation of the demixing transition in a binary symmetric Lennard-Jones fluid. In this system the demixing transition takes place between two phases of the same density but different compositions. The appropriateness of the reaction coordinate of classical nucleation theory is examined. Using paths harvested with transition path sampling, we investigate the nucleation mechanism and analyze the properties of critical nuclei obtained by determining the transition state ensemble. Our simulations show that despite the fact that the densities of the coexisting phases are equal, the density of the growing cluster plays a crucial role in the nucleation process: nucleation tends to proceed either via small, compact clusters with densities below that of the metastable fluid or via large clusters with even lower densities.
Surface, bulk, and interface electronic properties of nonpolar InN
Authors: Linhart W. M. , Veal T. D. , King P. D. C. , Koblmüller G. , Gallinat C. S. , Speck J. S. , McConville C. F.
Published: September 2010

The electronic properties of a-plane and m-plane InN have been investigated by x-ray photoemission spectroscopy, infrared reflectivity, and surface space-charge calculations. Electron accumulation has been observed at the surface of nonpolar InN and the surface Fermi level has been found to be lower than previously observed on InN samples. A high electron density in the InN close to the interface with GaN was found in each nonpolar InN sample.
Dielectric functions and interband transitions of In1−xAlxSb alloys
Authors: Yoon J. J. , Kim T. J. , Jung Y. W. , Aspnes D. E. , Kim Y. D. , Kim H. J. , Chang Y. C. , Shin S. H. , Song J. D.
Published: September 2010

Pseudodielectric functions ⟨ε⟩ of In1−xAlxSb ternary alloy films were determined from 1.5 to 6.0 eV by spectroscopic ellipsometry. Overlayer effects were minimized by performing in situ chemical etching to more accurately determine intrinsic bulk dielectric responses. Critical-point (CP) energies of structures were determined from numerically calculated second energy derivatives. Where necessary, Brillouin-zone origins were identified by electronic band structure calculations done with the linear augmented Slater-type orbital method. These calculations also showed increasing separation of the E2 and E2′ CP structures with increasing Al-composition
Mycobacterium shinjukuense sp. nov., a slowly growing, non-chromogenic species isolated from human clinical specimens
Authors: Saito Hajime , Iwamoto Tomotada , Ohkusu Kiyofumi , Otsuka Yoshihito , Akiyama Yasushi , Sato Shigeki , Taguchi Osamu , Sueyasu Yoshiko , Kawabe Yoshiko , Fujimoto Hisao , Ezaki Takayuki , Butler Ray
Published: September 2010

Seven isolates of a slowly growing, non-chromogenic Mycobacterium species were obtained from sputum and bronchial lavage fluid samples from elderly patients in different regions of Japan. These isolates were distinguished from related non-tuberculous species by colony morphology, positive results for Tween hydrolysis, catalase at 68 °C, nitrate reductase and pyrazinamidase and negative results for semi-quantitative catalase, urease and arylsulfatase. The mycolic acid pattern obtained by HPLC revealed a single cluster of late-eluting mycolic acids similar to but different from those of Mycobacterium malmoense ATCC 29571T. The 16S rRNA gene, 16S–23S internal transcribed spacer (ITS), rpoB and hsp65 sequences were unique in comparison with those of other mycobacteria. Comparison of 16S rRNA gene sequences showed that the isolates were most closely related to Mycobacterium tuberculosis H37RvT (21 base differences in 1508 bp; 98.6 % 16S rRNA gene sequence similarity). A representative strain, GTC 2738T, showed 91.9 % rpoB sequence similarity with Mycobacterium marinum strain M, 95 % hsp65 sequence similarity with Mycobacterium kansasii CIP 104589T and 81.1 % 16S–23S ITS sequence similarity with Mycobacterium gordonae ATCC 14470T. Phylogenetic analysis of concatenated sequences of the 16S rRNA, rpoB and hsp65 genes showed that strain GTC 2738T was located on a distinct clade adjacent to M. tuberculosis, M. ulcerans and M. marinum, with bootstrap values of 81 %. DNA–DNA hybridization demonstrated less than 70 % reassociation with type strains of genetically related species and supported the novel species status of the isolates. On the basis of this evidence, a novel species with the name Mycobacterium shinjukuense sp. nov. is proposed. The type strain, isolated from a sputum sample, is strain GTC 2738T( = JCM 14233T = CCUG 53584T).
Document, text and medium: concepts, theories and disciplines
Authors: Windfeld Lund Niels
Published: September 2010

Purpose

The purpose of this paper is first to provide a critical conceptual discussion of different use of the notion of text, especially in the case of expressions including words as well as images, second to consider the notion of document as an alternative to the notion of text, and finally to lay out a theoretical ground for a broad discipline of documentation studies.

Design/methodology/approach

The approach took the form of a conceptual analysis of a number of works in media and literary studies.

Findings

There were found a number of cases of contradictory use of the notion of text within the same work, talking about text in a broad overall sense covering all media as well as text as a distinctive concept separating words from images, while it was found through a conceptual history of the notion of document that the latter notion not only covers a written paper, but multiple media.

Research limitations/implications

In future research, one should consider the use of document as the concept for the expressions as a whole and dedicate the notion of text solely for the verbal part of the expressions and make more empirical analysis within this conceptual framework to see if it makes a difference in practice to change the overall concept from text to document.

Practical implications

Having a broad concept of document, it would be possible to be more flexible regarding the choose of proper media for documentation.

Originality/value

By making a critique of the notion of text and suggesting a broader concept of document as well as documentation, the paper provides a ground for reconsidering the classical disciplinary structure, divided into humanities as well as the information sciences and social sciences.