bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractThe 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

AbstractElectron 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

AbstractThe 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

AbstractThe 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

AbstractIrradiation 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

AbstractStudies 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

AbstractEphedrine 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

AbstractThe 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

AbstractDihydroazulenones 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

AbstractCycloaddition 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

AbstractOrdered 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

AbstractTreatment 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

AbstractIn 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

AbstractVanadyl‐ 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

AbstractA 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

SUMMARYThis 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

AbstractA 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

AbstractTerephthalsäure 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

AbstractAn 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

AbstractSeit 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

AbstractEs 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

AbstractEs 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

AbstractIn 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.