bluuebunny/crossref_metadata_2025 huggingface dataset:
One‐Dimensional Microwires Formed by the Co‐Assembly of Complementary Aromatic Donors and Acceptors
Authors: Wang Jie‐Yu , Yan Jing , Ding Lin , Ma Yuguo , Pei Jian
Published: May 2009

A truxene derivative (Tr3) with a C3 symmetric conjugated plane is synthesized; this derivative is a perfect match, in both size and structure, with its oxidized counterpart, the truxenone derivative (TrO3), a new electron acceptor that was recently reported. The complementary pair, Tr3 and TrO3, sets a good platform for the investigation of aromatic donor–acceptor interactions. Detailed 1H NMR experiments, photoluminescence spectroscopy, as well as differential scanning calorimetry are performed to investigate the interaction between Tr3 and TrO3, from solution to mesophase. One‐dimensional microbelts readily formed from a 1:1 mixture of Tr3 and TrO3. Scanning electron microscopy, powder X‐ray diffraction, as well as fluorescence microscopy are performed to elucidate their co‐assembly structure in the solid state. Moreover, modulation of the co‐assembly structure is easily realized by changing the concentration or mixing ratio. The present system opens the possibility of forming 1D heterostructures via electron donor–acceptor interaction, and its potential application as P–N junction and photowaveguide materials in optoelectronic devices.
Doping of Conjugated Polythiophenes with Alkyl Silanes
Authors: Kao Chi Yueh , Lee Bumsu , Wielunski Leszek S. , Heeney Martin , McCulloch Iain , Garfunkel Eric , Feldman Leonard C. , Podzorov Vitaly
Published: May 2009

A strong modification of the electronic properties of solution‐processable conjugated polythiophenes by self‐assembled silane molecules is reported. Upon bulk doping with hydrolized fluoroalkyl trichlorosilane, the electrical conductivity of ultrathin polythiophene films increases by up to six orders of magnitude, reaching record values for polythiophenes: (1.1 ± 0.1) × 103 S cm−1 for poly(2,5‐bis(3‐tetradecylthiophen ‐2‐yl)thieno[3,2‐b]thiophene) (PBTTT) and 50 ± 20 S cm−1 for poly(3‐hexyl)thiophene (P3HT). Interband optical absorption of the polymers in the doped state is drastically reduced, making these highly conductive films transparent in the visible range. The dopants within the porous polymer matrix are partially crosslinked via a silane self‐polymerization mechanism that makes the samples very stable in vacuum and nonpolar environments. The mechanism of SAM‐induced conductivity is believed to be based on protonic doping by the free silanol groups available within the partially crosslinked SAM network incorporated in the polythiophene structure. The SAM‐doped polythiophenes exhibit an intrinsic sensing effect: a drastic and reversible change in conductivity in response to ambient polar molecules, which is believed to be due to the interaction of the silanol groups with polar analytes. The reported electronic effects point to a new attractive route for doping conjugated polymers with potential applications in transparent conductors and molecular sensors.
Knowledge‐Based Approach towards Hydrolytic Degradation of Polymer‐Based Biomaterials
Authors: Hofmann Dieter , Entrialgo‐Castaño Maria , Kratz Karl , Lendlein Andreas
Published: May 2009

The concept of hydrolytically degradable biomaterials was developed to enable the design of temporary implants that substitute or fulfill a certain function as long as required to support (wound) healing processes or to control the release of drugs. Examples are surgical implants, e.g., sutures, or implantable drug depots for treatment of cancer. In both cases degradability can help to avoid a second surgical procedure for explanation. Although degradable surgical sutures are established in the clinical practice for more than 30 years, still more than 40% of surgical sutures applied in clinics today are nondegradable.1 A major limitation of the established degradable suture materials is the fact that their degradation behavior cannot reliably be predicted by applying existing experimental methodologies. Similar concerns also apply to other degradable implants. Therefore, a knowledge‐based approach is clearly needed to overcome the described problems and to enable the tailored design of biodegradable polymer materials. In this Progress Report we describe two methods (as examples for tools for this fundamental approach): molecular modeling combining atomistic bulk interface models with quantum chemical studies and experimental investigations of macromolecule degradation in monolayers on Langmuir–Blodgett (LB) troughs. Finally, an outlook on related future research strategies is provided.
Exploiting the Kubas Interaction in the Design of Hydrogen Storage Materials
Authors: Hoang Tuan K. A. , Antonelli David M.
Published: May 2009

Hydrogen adsorption and storage using solid‐state materials is an area of much current research interest, and one of the major stumbling blocks in realizing the hydrogen economy. However, no material yet researched comes close to reaching the DOE 2015 targets of 9 wt% and 80 kg m−3 at this time. To increase the physisorption capacities of these materials, the heats of adsorption must be increased to ∼20 kJ mol−1. This can be accomplished by optimizing the material structure, creating more active species on the surface, or improving the interaction of the surface with hydrogen. The main focus of this progress report are recent advances in physisorption materials exhibiting higher heats of adsorption and better hydrogen adsorption at room temperature based on exploiting the Kubas model for hydrogen binding: (η2‐H2)–metal interaction. Both computational approaches and synthetic achievements will be discussed. Materials exploiting the Kubas interaction represent a median on the continuum between metal hydrides and physisorption materials, and are becoming increasingly important as researchers learn more about their applications to hydrogen storage problems.
Physics and Applications of Bismuth Ferrite
Authors: Catalan Gustau , Scott James F.
Published: May 2009

BiFeO3 is perhaps the only material that is both magnetic and a strong ferroelectric at room temperature. As a result, it has had an impact on the field of multiferroics that is comparable to that of yttrium barium copper oxide (YBCO) on superconductors, with hundreds of publications devoted to it in the past few years. In this Review, we try to summarize both the basic physics and unresolved aspects of BiFeO3 (which are still being discovered with several new phase transitions reported in the past few months) and device applications, which center on spintronics and memory devices that can be addressed both electrically and magnetically.
Challenges and Progress in High‐Throughput Screening of Polymer Mechanical Properties by Indentation
Authors: Kranenburg Johannes M. , Tweedie Catherine A. , van Vliet Krystyn J. , Schubert Ulrich S.
Published: May 2009

Depth‐sensing or instrumented indentation is an experimental characterization approach well‐suited for high‐throughput investigation of mechanical properties of polymeric materials. This is due to both the precision of force and displacement, and to the small material volumes required for quantitative analysis. Recently, considerable progress in the throughput (number of distinct material samples analyzed per unit time) of indentation experiments has been achieved, particularly for studies of elastic properties. Future challenges include improving the agreement between various macroscopic properties (elastic modulus, creep compliance, loss tangent, onset of nonlinear elasticity, energy dissipation, etc.) and their counterpart properties obtained by indentation. Sample preparation constitutes a major factor for both the accuracy of the results and the speed and efficiency of experimental throughput. It is important to appreciate how this processing step may influence the mechanical properties, in particular the onset of nonlinear elastic or plastic deformation, and how the processing may affect the agreement between the indentation results and their macroscopic analogues.
Carbon‐Based Field‐Effect Transistors for Nanoelectronics
Authors: Burghard Marko , Klauk Hagen , Kern Klaus
Published: May 2009

In this review, the suitability of the major types of carbon nanostructures as conducting channels of field‐effect transistors (FETs) is compared on the basis of the dimensionality and size of their π‐conjugated system. For each of these materials, recent progress in its synthesis, electrical and structural characterization, as well as its implementation into various gate configurations is surveyed, with emphasis laid onto nanoscale aspects of the FET design and the attainable device performance. Finally, promising future research directions, such as the integration of different carbon nanostructures into novel device architectures, are outlined.
Kohärente mehrdimensionale Schwingungsspektroskopie von Biomolekülen: Konzepte, Simulationen und Herausforderungen
Authors: Zhuang Wei , Hayashi Tomoyuki , Mukamel Shaul
Published: May 2009

Die Schwingungsantwort komplexer Moleküle auf Sequenzen von Infrarotpulsen liefert Momentaufnahmen ihrer Struktur und Dynamik im Femtosekundenbereich. Diese Technik, die analog ist zur mehrdimensionalen NMR‐Spektroskopie und Korrelationen von Bewegungsvorgängen während kontrollierter Zeitintervalle abbildet (siehe Schema), wurde zur Untersuchung von Proteinfaltungen, Wasserstoffbrücken, Lipidmembranen und chemischen Umlagerungen genutzt.

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Die Schwingungsanregung komplexer Biomoleküle mit Femtosekunden‐Infrarotpulsen ermöglicht einzigartige Einblicke in ihre Struktur, Dynamik und fluktuierende Umgebung. Dieser Aufsatz stellt die Grundlagen moderner zweidimensionaler Infrarot(2DIR)‐Methoden vor, die analog sind zu den Techniken der mehrdimensionalen NMR‐Spektroskopie. Störungstheoretische Ansätze zur Berechnung der nichtlinearen optischen Eigenschaften von gekoppelten lokalisierten Chromophoren werden eingeführt und auf Schwingungsübergänge im Amidrückgrat von Proteinen, flüssigem Wasser, Membranlipiden und Amyloidfibrillen angewendet. Die Signalanalyse erfolgt durch klassische Moleküldynamiksimulationen in Kombination mit einem fluktuierenden Hamilton‐Operator für gekoppelte lokalisierte anharmonische Schwingungen, dessen Abhängigkeit von der lokalen elektrostatischen Umgebung durch Ab‐initio‐Daten parametrisiert wird. Die verwendeten Simulationsverfahren (Kumulanten‐Entwicklung von Gauß‐Fluktuationen, Streuung von Quasipartikeln, stochastische Liouville‐Gleichungen, direkte numerische Reihenentwicklungen) sind in den SPECTRON‐Code integriert, der eine Schnittstelle mit Standardmoleküldynamikmethoden hat. Ebenfalls diskutiert werden chiralitätsinduzierte Techniken zur Auflösungssteigerung sowie die Signaturen von konformativen und H‐Brücken‐Fluktuationen, Proteinfaltungsvorgängen und chemischen Austauschprozessen.
Protein Conformational Flexibility from Structure‐Free Analysis of NMR Dipolar Couplings: Quantitative and Absolute Determination of Backbone Motion in Ubiquitin
Authors: Salmon Loïc , Bouvignies Guillaume , Markwick Phineus , Lakomek Nils , Showalter Scott , Li Da‐Wei , Walter Korvin , Griesinger Christian , Brüschweiler Rafael , Blackledge Martin
Published: May 2009

Ein zuverlässiges Verfahrenzur Bestimmung der Bewegungen des Proteingerüsts über einen Zeitraum von Piko‐ bis Millisekunden auf der Grundlage dipolarer Restkopplungen erfordert keine Skalierung mithilfe einer externen Referenz. Die Ergebnisse für Ubiquitin (blau im Graph: experimentelle N‐HN‐Ordnungsparameter) entsprechen in Amplitude, Art und Verteilung sehr gut der Bewegung, die in einer 400‐ns‐Moleküldynamiktrajektorie von Ubiquitin ermittelt wurde (rot).

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Komplexe mit dativen Bindungen zwischen d‐ und s‐Block‐Metallen: Synthese und Struktur von [(Cy3P)2Pt‐Be(Cl)X] (X=Cl, Me)
Authors: Braunschweig Holger , Gruss Katrin , Radacki Krzysztof
Published: May 2009

Ein Platin‐Beryllium‐Addukt (siehe Bild) wurde durch Reaktion von [Pt(PCy3)2] mit BeCl2 erhalten. Die Umsetzung mit Methyllithium führte zur Substitution eines Liganden am Berylliumzentrum. Beide Komplexe wurden strukturell charakterisiert und zeichnen sich durch eine präzedenzlose Zwei‐Zentren‐zwei‐Elektronen‐Bindung zwischen einem Übergangsmetall und Beryllium aus.

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Stereocontrolled Synthesis of Highly Functionalized Quaternary Carbon Centers: A Route to α‐Substituted Serines
Authors: Ariza Xavier , Cornellà Josep , Font‐Bardia Mercè , Garcia Jordi , Ortiz Jordi , Sánchez Carolina , Solans Xavier
Published: May 2009

Drei in einer Reihe! Hoch funktionalisierte quartäre Aminopolyole mit drei benachbarten asymmetrischen Kohlenstoffzentren wurden durch Tandem‐Hydroborierung des Allens 1 und Addition an ein Aldehyd hergestellt (siehe Schema; Cy=Cyclohexyl, TBDPS=tert‐Butyldiphenylsilyl, Ts=4‐Toluolsulfonyl). Dieser Eintopfprozess bietet Zugang zu fortgeschrittenen Zwischenprodukten für die enantioselektive Synthese von α‐substituierten Serinen.

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Sequenzierung einzelner DNA‐Moleküle in Echtzeit
Authors: Ibach Jenny , Brakmann Susanne
Published: May 2009

Kleiner geht's nicht: Durch direkte Beobachtung einer DNA‐Polymerase‐basierten “Sequenziermaschine” mithilfe von Einzelmolekültechniken gelang kürzlich eine Sequenzierung durch Synthese in Echtzeit. Nucleotide mit einer Fluoreszenzmarkierung am 5′‐Phosphatrest und Nullmode‐Lichtwellenleiter waren entscheidend für den Erfolg dieses Experiments, das ein kostengünstiges Verfahren zur Genomsequenzanalyse verspricht.

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N‐Heterocyclic Carbenes as Efficient Organocatalysts for CO2 Fixation Reactions
Authors: Kayaki Yoshihito , Yamamoto Masafumi , Ikariya Takao
Published: May 2009

Fixe Idee: N‐Heterocyclische Carbene und ihre CO2‐Addukte sind wirksame Organokatalysatoren für die Synthese von Carbonaten durch Addition von CO2 an Propargylalkohole oder Epoxide unter milden, lösungsmittelfreien Bedingungen (siehe Schema). Die erhöhte Lewis‐Basizität von Imidazol‐2‐ylidenen mit elektronenschiebenden N,N′‐Dialkylgruppen macht es möglich, CO2 als nucleophiles Fragment in chemischen Fixierungsprozessen einzusetzen.

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A Supramolecularly Assisted Transformation of Block‐Copolymer Micelles into Nanotubes
Authors: Kim Sung Ho , Nederberg Fredrik , Jakobs Robert , Tan Jeremy P. K. , Fukushima Kazuki , Nelson Alshakim , Meijer E. W. , Yang Yi Yan , Hedrick James L.
Published: May 2009

Once around the block: Incorporation of a rigid hydrogen‐bonding benzamide unit, placed at the interface between two polymer blocks, in poly(ethylene glycol) (PEG)–(thio)urea–poly(L‐lactide) (PLLA) block copolymers transforms the morphology of the block copolymers, from spherical micelles, as formed by PEG‐PLLA diblock copolymers, into nanotubes in solution.

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Enantioselective Synthesis of β‐Iodo Morita–Baylis–Hillman Esters by a Catalytic Asymmetric Three‐Component Coupling Reaction
Authors: Senapati Bidyut Kumar , Hwang Geum‐Sook , Lee Sungil , Ryu Do Hyun
Published: May 2009

A catalytic route toward chiral Morita–Baylis–Hillman esters by asymmetric coupling between α,β‐acetylenic esters, aldehydes, and trimethylsilyl iodide has been developed (see scheme). The reaction proceeds with high to excellent enantioselectivities, and the products can be transformed into β‐branched derivatives in a single step and with excellent retention of configuration. TMS=trimethylsilyl

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Protein Conformational Flexibility from Structure‐Free Analysis of NMR Dipolar Couplings: Quantitative and Absolute Determination of Backbone Motion in Ubiquitin
Authors: Salmon Loïc , Bouvignies Guillaume , Markwick Phineus , Lakomek Nils , Showalter Scott , Li Da‐Wei , Walter Korvin , Griesinger Christian , Brüschweiler Rafael , Blackledge Martin
Published: May 2009

A robust procedurefor the determination of protein‐backbone motions on time scales of pico‐ to milliseconds directly from residual dipolar couplings has been developed that requires no additional scaling relative to external references. The results for ubiquitin (blue in graph: experimental NHN order parameters) correspond closely to the amplitude, nature, and distribution of motion found in a 400 ns molecular‐dynamics trajectory of ubiquitin (red).

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Complexes with Dative Bonds between d‐ and s‐Block Metals: Synthesis and Structure of [(Cy3P)2PtBe(Cl)X] (X=Cl, Me)
Authors: Braunschweig Holger , Gruss Katrin , Radacki Krzysztof
Published: May 2009

A platinum–beryllium adduct (see structure) was prepared by the reaction of [Pt(PCy3)2] and BeCl2. Treatment with methyllithium resulted in ligand substitution at the beryllium center. Both complexes were structurally characterized and display unprecedented two‐center two‐electron bonds between a transition metal and beryllium.

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N‐Heterocyclic Carbenes as Efficient Organocatalysts for CO2 Fixation Reactions
Authors: Kayaki Yoshihito , Yamamoto Masafumi , Ikariya Takao
Published: May 2009

Getting a fix: N‐heterocyclic carbenes (NHCs) and NHC–CO2 adducts serve as potent organocatalysts for carbonate synthesis by the addition of a CO2 unit to propargylic alcohols or epoxides under mild and solvent‐free reaction conditions (see scheme). The enhanced Lewis basicity of imidazol‐2‐ylidenes bearing electron‐donating alkyl groups on the nitrogen atoms leads to utilizing CO2 as a nucleophilic fragment in the chemical fixation processes.

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Cover Picture: Substituent‐Free Gallium by Hydrogenolysis of Coordinated GaCp*: Synthesis and Structure of Highly Fluxional [Ru2(Ga)(GaCp*)7(H)3] (Angew. Chem. Int. Ed. 21/2009)
Authors: Cadenbach Thomas , Gemel Christian , Schmid Rochus , Halbherr Markus , Yusenko Kirill , Cokoja Mirza , Fischer Roland A.
Published: May 2009

Soft skin, hard core …︁ is the basic principle for the formation of a nano‐alloy from molecular precursors. The co‐hydrogenolysis of ruthenium complexes in presence of GaCp* gives the isolable key intermediate [Ru2(Ga)(GaCp*)7(H)3] featuring a substituent‐free bridging gallium atom. From this “embryonic” species Ru/Ga phases are formed by complete cleavage of the protective Cp* shell (depicted as an eggshell in the Cover picture), as described by R. A. Fischer et al. in their Communication on page 3872 ff.

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Inside Cover: Giant Pores in a Chromium 2,6‐Naphthalenedicarboxylate Open‐Framework Structure with MIL‐101 Topology (Angew. Chem. Int. Ed. 21/2009)
Authors: Sonnauer Andreas , Hoffmann Frank , Fröba Michael , Kienle Lorenz , Duppel Viola , Thommes Matthias , Serre Christian , Férey Gérard , Stock Norbert
Published: May 2009

Highly porous and stable metal–organic frameworks, isoreticular to MIL‐101 and with cage diameters of 39 and 46 Å, are obtained by replacement of the 1,4‐benzenedicarboxylate ligands in that framework with 2,6‐naphthalenedicarboxylate. In their Communication on page 3791 ff., N. Stock and co‐workers report high‐throughput methods used to optimize reaction conditions and characterization of this MTN zeolite analogue by a combination of structure simulation, electron microscopy, and sorption measurements.

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Structural development Of TMMA and SSQXN‐8 as porous chelating resins
Authors: Ibrahim Gehan M. , Ahmad Mohamed I. , El‐Gammal Belal
Published: May 2009

Superfast kinetics of Nd+3, Eu+3, and Gd+3 ions were studied on the surfaces of N,N,N\,N\‐tetramethylmalonamide (TMMA) and silsesquioxane (SSQXN‐8) resins. TMMA and SSQXN‐8 were prepared by suspension polymerization and sol–gel routes, respectively. They were identified using elemental analysis, FTIR, H‐NMR, 13C‐NMR, MIP, and BET surface area. Kinetic investigations were performed in batch conditions and different models were used to fit the data; Boyd and Helfferich models were found the best. The diffusion of the ions through the resins were very fast and found to be in the order of 10−16 m2/S. Effective diffusions of the studied ions were found to be 10−15 order of magnitude and directly proportional to the kinetic energy of the transition state. ΔS* values from −166.044 to −179.297 J mol−1 K−1 were estimated as entropy stability factors of the system. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of a polyimide composite filled with corundum as a kind of precision grinding slice
Authors: Qingsudu Si , Chen Chen , Xianghua Xie , Yaming Dong
Published: May 2009

By using a two‐step synthetic method, a novel grinding material, SiC and polyimide grinding slice, is prepared. This grinding slice can be used for mechanical planarization of hard and brittle materials, such as silicon, optical glass, advanced ceramics, specials metal, jewelry, disks etc. For observing the physical and chemical properties of the slice, scanning electron microscopy, FTIR spectroscopy, thermal gravimetric analysis, tensile strength, and elongation at break are used. All the experimental data indicate that the SiC/PI slice will be a very useful grinding material for obtaining a precision surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Molecular imprinted solid‐phase extraction of huperzine A from Huperzia Serrata
Authors: Wang Guosong , Cao Qiue , Zhu Xiufang , Yang Xueqiong , Yang Minghui , Ding Zhongtao
Published: May 2009

On the basis of the non‐covalent interaction between template and monomer, porous molecularly imprinted polymers (MIPs) were synthesized by a thermal‐initiated polymerization method using huperzine A as template, acrylamide, or methacrylic acid as function monomer, ethylene glycol dimethacrylate as cross‐linking agent. The interaction between template and functional monomers was studied by UV spectrophotometry, which showed a formation of huperzine A‐monomer complexes with stoichiometric ratio of 1 : 2 in the pre‐polymerized systems. The resultant MIP particles were tested in the equilibrium binding experiment to analyze their adsorption ability to huperzine A, and were characterized by Fourier Transform Infrared (FTIR) study. The recognition properties of MIP were estimated in solid‐phase extraction by selecting four compounds (isolated from the Chinese herb Huperzia serrata) as substrates, and were compared with and prior to those of the NIP. High affinity and adsorption of MIP1 which was prepared in chloroform with huperzine A as imprinted molecule, and acrylamide (AM) as functional monomer, made an attractive application of MIP1 in separation processes. In final, using MIP1 solid‐phase extraction micro‐column, huperzine A was enriched and separated from the real extraction sample of Huperzia serrata. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and properties of hydrogels of poly(acrylic‐co‐acroloyl β‐cyclodextrin)
Authors: Huang Yi , Fan Xiao‐Dong
Published: May 2009

Novel acrylic monomers (β‐CD‐A and β‐CD‐6‐EA) containing β‐cyclodextrin (β‐CD) with different extent of substitution were prepared by using dicyclohexylcarbodiimide (DCC) as a condensation agent at room temperature. Two kinds of functional hydrogels were also synthesized by copolymerization of β‐CD‐A and β‐CD‐6‐EA with acrylic acid (AAc) using a redox initiator system in aqueous solution. The nuclear magnetic resonance (1H NMR), infrared spectroscopy (IR), thermogravimetric analysis (TGA) were employed to character the molecular structures of β‐CD modified monomers and their copolymers. The swelling experiments indicate that the hydrogels with different equilibrium swelling ratio (ESR) possess obvious pH‐sensitivity and distinct dynamic swelling behavior. Using an anti‐cancer drug, chlorambucil (CHL), able to form complexes with β‐CD in water, as a model compound, the controlled drug release behaviors of these hydrogels were investigated. The release behavior of CHL from two kinds of hydrogels synthesized reveals that the release rate of CHL can be effectively controlled by pH values, cross‐linking density, and β‐CD content. In addition, it is found that the β‐CD with the proper frame and concentration can increase release efficiency of CHL from the hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and investigation of ethylene–vinyl acetate copolymer/silicone rubber/clay nanocomposites
Authors: Fang Shoulin , Hu Yuan , Song Lei , Wu Jing
Published: May 2009

In this article, the combination of silicone rubber (SR) elastomer with synthetic iron montmorillonite (Fe‐MMT) to form a kind of new flame‐retardant system based on an ethylene–vinyl acetate (EVA) copolymer is first reported. Also, the flame retardancy of the EVA/SR/Fe‐MMT hybrid are compared with that of EVA/SR/natural sodium montmorillonite. The structures of the nanocomposites were characterized with X‐ray diffraction and transmission electron microscopy. Cone calorimeter tests and thermogravimetric analysis were used to evaluate the flame‐retardant properties and thermal stability of the composites, respectively. In addition, tensile tests were carried out with a universal testing machine, and the morphology of the fracture surface was observed with environmental scanning electron microscopy. We found that SR/organophilic montmorillonite (Fe‐OMT) was more effective in reducing the primary peak heat release rate of the nanocomposite, and the EVA/SR/Fe‐OMT hybrid had a higher thermal stability in the deacetylated polymer than EVA/SR/sodium organophilic montmorillonite. Moreover, the exfoliated EVA/SR/Fe‐OMT nanocomposite displayed excellent mechanical properties because of a better dispersion of Fe‐OMT in the polymer matrix, and a possible mechanism is discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of intercalated lamellar hydroxyapatite/gelatin nanocomposite for bone substitute application
Authors: Zuo Guifu , Liu Chao , Luo Honglin , He Fang , Liang Hui , Wang Jiehua , Wan Yizao
Published: May 2009

Hydroxyapatite (HAp)/polymer composites have been widely investigated for bone substitute applications in recent years. Inspired by the arrangement of ordered organic and inorganic layers in natural bones and seashells, for the first time a novel intercalated nanocomposite of gelatin and lamellar HAp was prepared via solution intercalation process. X‐ray diffraction (XRD) results showed that the basal spacing of HAp lamellas enlarged by 3.0 nm from 3.1 nm to 6.1 nm, indicating that the gelatin molecules had been intercalated into the gallery of lamellar HAp. The microstructures of pure lamellar HAp and intercalated gelatin/HAp nanocomposite were observed by transmission electron microscopy (TEM) analysis. Fourier transform infrared spectroscopy (FT‐IR) analysis revealed that there were chemical interactions between gelatin molecules and HAp. Thermogravimetric analysis (TGA) results confirmed that thermal stability of the composites was enhanced. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Morphology, rheological behavior, and thermal stability of PLA/PBSA/POSS composites
Authors: Wang Ruyin , Wang Shifeng , Zhang Yong
Published: May 2009

Octavinyl POSS (vPOSS) and epoxycyclohexyl POSS (ePOSS) were separately incorporated into the poly(lactic acid)/poly(butylene succinate‐co‐adipate) (PLA/PBSA) blend by melt mixing. Field emission scanning electron microscopy and X‐ray diffraction analysis revealed that vPOSS existed as crystalline aggregates, whereas ePOSS was more uniformly dispersed in the composites. The storage modulus and complex viscosity slightly decreased after the addition of vPOSS, but significantly increased after the addition of ePOSS, indicating the higher melt elasicity and broader processing window of the PLA/PBSA after the addition of ePOSS. The chloroform solutions of PLA/PBSA/ePOSS composites were turbid in appearance, and the extracted POSS showed absorbant peaks assigned to the vibration of OH and CO groups in the Fourier transform infrared spectroscopy analysis, indicating the reactions between ePOSS and the PLA/PBSA. Polarized optical microscopy analysis revealed that the two types of POSS could act as nucleating agents for PLA, and enhance its crystallization ability. Thermal gravimetric analysis showed that the addition of the two types of POSS increased the decomposition temperature and activation energy, consequently retarding the thermal degradation of PLA/PBSA. The retardation of degradation is more significant with the addition of ePOSS, for the reactions reduced the end groups of PLA/PBSA as well as the molecular chain mobility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci 2009
Preparation of a silica/poly(n‐butyl acrylate‐co‐acrylic acid) composite latex and its pressure‐sensitive properties
Authors: Wang Nongyue , Guo Yakun , Xu Hongping , Liu Xinran , Zhang Liqun , Qu Xiongwei , Zhang Liucheng
Published: May 2009

Silica with an average particle size of 125 nm was prepared by the sol–gel reaction of tetraethoxysilane with a base catalyst and then modified with a vinyl‐functionalized silane [γ‐methacryloxypropyl trimethoxysilane (MPS)]. The composite latex, with the modified silica as the core and poly(n‐butyl acrylate‐co‐acrylic acid) [poly(BA‐co‐AA)] polymer as the shell, was synthesized by a semicontinuous emulsion polymerization and used as a pressure‐sensitive adhesive. The structures were characterized by Fourier transform infrared spectrometry, X‐ray photoelectron spectroscopy, elemental analysis, and transmission electron microscopy. The particle sizes of the silica and MPS‐modified silica (MPS–silica)/poly(BA‐co‐AA) composite latexes were determined by dynamic light scattering in a semicontinuous emulsion polymerization online. The monomers of n‐butyl acrylate and acrylic acid grew around the MPS–silica particles without significant secondary nucleation, and the composite latexes exhibited a core–shell structure with the modified silica particles enwrapped in poly(BA‐co‐AA). To compare the adhesion properties, including the loop tack force, peel strength, and shear resistance, by Fédération Internationale des Fabricants et Transformateurs d'Adhésifs et Thermocollants sur Papiers et Autres Supports test methods, poly(methyl methacrylate‐co‐allyl methacrylate)/poly(BA‐co‐AA) latex and the full poly(BA‐co‐AA) latex were prepared with the same particle size and the same emulsion polymerization process. The shear resistance of the composite latex film greatly increased after the addition of the silica to the core of the poly(BA‐co‐AA) latex. The relationships between the adhesive properties and the different structures in the core components were examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
N‐(Indazolyl)benzamido Derivatives as CDK1 Inhibitors: Design, Synthesis, Biological Activity, and Molecular Docking Studies
Authors: Raffa Demetrio , Maggio Benedetta , Cascioferro Stella , Raimondi Maria Valeria , Daidone Giuseppe , Plescia Salvatore , Schillaci Domenico , Cusimano Maria Grazia , Titone Lucina , Colomba Claudia , Tolomeo Manlio
Published: May 2009

A series of N‐1H‐indazole‐1‐carboxamides has been synthesized and their effects on both CDK1 / cyclin B and the K‐562 (human chronic myelogenus leukemia) cell line were evaluated. Using a computational model, we have observed that all the most active compounds 9e, f, i–n exhibited the same binding mode of purvanalol A in the ATP‐binding cleft. Although they were able to moderately inhibit the leukemic cell line K‐562 and to show inhibitory activity against the Cdc2‐Cyclin B kinase in the low micromolar range, they turned out to be non‐cytotoxic against HuDe (IZSL) primary cell cultures from human derm. These preliminary results are quite encouraging in view of the low toxicity demonstrated by the above‐mentioned compounds.
Synthesis and Biological Activities of 2,4‐Diaminopteridine Derivatives
Authors: Ma Fei , Lü Gang , Zhou Wei‐Fen , Wang Qiu‐Juan , Zhang Yi‐Hua , Yao Qi‐Zheng
Published: May 2009

Substituted 2,4‐diaminopteridine derivatives10a–10lwere prepared in moderate to good yield. Their structures were confirmed by1H‐NMR and MS spectroscopy, as well as by elemental analysis. Their inhibitory properties against inducible nitric oxide synthase (iNOS) were evaluatedin vitro. Biological tests indicated that compound10a,10d,10e,10h,10i, and10lshowed potent inhibitory activities similar to that of methotrexate (MTX), while the activities of compound10b,10c,10f,10g,10j, and10kare stronger than MTX. Two compounds, i. e.,10b(IC50= 18.85 μM) and10i(IC50= 24.08 μM) were further studied for their effect on septic shock in rats and immunologically liver injured mice (in vivo). The results demonstrated that10band10ihad the capacity to increase the blood pressure in septic shock and showed notable protective activities on immunological hepatic injury.
1 D Tubular and 2 D Metal–Organic Frameworks Based on a Flexible Amino Acid Derived Organic Spacer
Authors: Rebilly Jean‐Noël , Bacsa John , Rosseinsky Matthew J.
Published: May 2009

Flexible, yet rigid! A ligand derived from glutamic acid generates chiral MOF architectures ranging from 1D to 2D that are organized in the crystal through a complex hierarchy of coordination and hydrogen bonds that include encapsulation of solvent molecules. The flexibility of the ligand backbone gives access to several topologies and dimensionalities depending on the type of metal center used in the synthesis.

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The organic ligand bgxH4, resulting from the condensation of two glutamate moieties on a xylene core, has been designed to generate chiral metal–organic frameworks with increased metal–metal distances in order to favor their potential porosity. The in situ reactivity of the ligand, through cyclization, led to the bpgxH2 ligand, which displays an extremely rich architectural potential. Under formate‐generating conditions, two 1D tubular and one 2D MOFs based on bpgxH2 have been obtained, incorporating up to three different organic linkers, and organized in an exquisite hierarchical way by the combined effects of the flexibility, the coordinating groups, and the H‐bonding groups of the ligand. Furthermore, the tubular structures display pockets where water molecules are encapsulated.
Finite time agreement protocol design of multi‐agent systems with communication delays
Authors: Wang Li , Chen Zengqiang , Liu Zhongxin , Yuan Zhuzhi
Published: May 2009

In this paper, the finite‐time agreement problem of continuous‐time multi‐agent systems with communication delays is considered. First, the multi‐agent system researched in the paper is described. Second, some notations and lemmas used in the paper are given. Then, agreement protocols for continuous (but non‐smooth) multi‐agent systems are proposed, which ensure that the states of agents reach agreement in finite time. The stability analysis and simulations are presented to show the effectiveness of the method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Simultaneous stabilization for a collection of nonlinear control systems in canonical form
Authors: Wu Jenq‐Lang
Published: May 2009

A controller design method is provided to simultaneously stabilize a collection of nonlinear control systems in canonical form. It is shown that, under a mild assumption, any collection of nonlinear systems in canonical form can be simultaneously stabilized by one continuous state feedback controller. A constructive universal formula is presented explicitly. An illustrative example is given to demonstrate the validity of the method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Fuzzy multipath filter with Kalman algorithm for tracking a low‐altitude target
Authors: Chen Yee Ming , Wang Wen‐Shiang
Published: May 2009

To process tracking low‐altitude targets with multipath propagation is a difficult task. The difficulty is derived from a large number of uncertain knowledge (parameters) such as the radar waveform frequency, the specific signal processing, the surface reflectivity, the actual target elevation and range, etc. This paper offers a technique based on fuzzy logic to solve the uncertain measurement error by multipath propagation. Also, we apply quantitative analysis presenting the degree of multipath effect required to achieve the aforementioned goal. Meanwhile, tracking filter estimation is used to reduce the measurement error by the multipath propagation. After the simulation, the fuzzy‐logic‐based technique not only can simplify the process of the model building by the interacting multiple model but also can promote the tracking accuracy. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Delay‐dependent robust stability and stabilization for uncertain discrete singular systems with delays
Authors: Ma Shuping , Zhang Chenghui , Cheng Zhaolin
Published: May 2009

The robust stability and robust stabilization for time‐delay discrete singular systems with parameter uncertainties is discussed. A delay‐dependent linear matrix inequality (LMI) condition for the time‐delay discrete systems to be nonsingular and stable is given. Based on this condition and the restricted system equivalent transformation, the delay‐dependent LMI condition is proposed for the time‐delay discrete singular systems to be admissible. With this condition, the problems of robust stability and robust stabilization are solved, and the delay‐dependent LMI conditions are obtained. Numerical examples illustrate the effectiveness of the method given in the paper. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Observer‐based non‐fragile control against measurement disturbances and controller perturbations for discrete systems with state delay
Authors: Fang Xiaosheng , Wang Jingcheng
Published: May 2009

This paper investigates the observer‐based non‐fragile control problem for a class of discrete time delay systems with measurement disturbances and controller perturbations. A simultaneous state and disturbance estimation technique is developed by designing a state observer for a descriptor system obtained from the original system. Based on this observer, the design method of a non‐fragile controller is then formulated and the controller design problem is transformed to a convex optimization problem, which can be solved by a linear matrix inequality approach. In this design, the additive and multiplicative forms of uncertainties which perturb the gains of control and observer are both considered. The resultant non‐fragile observer‐based controller guarantees that the closed‐loop system is asymptotically stable and can tolerate measurement disturbances and a certain degree of controller parameter perturbation. A numerical example is given to illustrate the effectiveness of the proposed design method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Optimal disturbance rejection control for singularly perturbed composite systems with time‐delay
Authors: Zhang Bao‐Lin , Tang Gong‐You , Yue Dong
Published: May 2009

The optimal control problem for a class of singularly perturbed time‐delay composite systems affected by external disturbances is investigated. The system is decomposed into a fast linear subsystem and a slow time‐delay subsystem with disturbances. For the slow subsystem, the feedforward compensation technique is proposed to reject the disturbances, and the successive approximation approach (SAA) is applied to decompose it into decoupled subsystems and solve the two‐point boundary value (TPBV) problem. By combining with the optimal control law of the fast subsystem, the feedforward and feedback composite control (FFCC) law of the original composite system is obtained. The FFCC law consists of analytic state feedback and feedforward terms and a compensation term which is the limit of the adjoint vector sequence. The compensation term can be obtained from an iteration formula of adjoint vectors. Simulation results are employed to test the validity of the proposed design algorithm. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Transposable elements: powerful facilitators of evolution
Authors: Oliver Keith R. , Greene Wayne K.
Published: May 2009

Transposable elements (TEs) are powerful facilitators of genome evolution, and hence of phenotypic diversity as they can cause genetic changes of great magnitude and variety. TEs are ubiquitous and extremely ancient, and although harmful to some individuals, they can be very beneficial to lineages. TEs can build, sculpt, and reformat genomes by both active and passive means. Lineages with active TEs or with abundant homogeneous inactive populations of TEs that can act passively by causing ectopic recombination are potentially fecund, adaptable, and taxonate readily. Conversely, taxa deficient in TEs or possessing heterogeneous populations of inactive TEs may be well adapted in their niche, but tend to prolonged stasis and may risk extinction by lacking the capacity to adapt to change, or diversify. Because of recurring intermittent waves of TE infestation, available data indicate a compatibility with punctuated equilibrium, in keeping with widely accepted interpretations of evidence from the fossil record. We propose a general and holistic synthesis on how the presence of TEs within genomes makes them flexible and dynamic, so that genomes themselves are powerful facilitators of their own evolution
The function of vascular endothelial growth factor
Authors: Nieves Bonnie J. , D'Amore Patricia A. , Bryan Brad A.
Published: May 2009

Vascular endothelial growth factor (VEGF) is considered the master regulator of angiogenesis during growth and development, as well as in disease states such as cancer, diabetes, and macular degeneration. This review details our current understanding of VEGF signaling and discusses the benefits and unexpected side effects of promising anti‐angiogenic therapeutics that are currently being used to inhibit neovacularization in tumors. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
Functional Analysis of MycE and MycF, Two O‐Methyltransferases Involved in the Biosynthesis of Mycinamicin Macrolide Antibiotics
Authors: Li Shengying , Anzai Yojiro , Kinoshita Kenji , Kato Fumio , Sherman David H.
Published: May 2009

Mg motors: We characterized the in vitro function of MycE and MycF, two O‐methyltransferases involved in the biosynthesis of mycinamicin antibiotics. Each enzyme was confirmed to be an S‐adenosyl‐L‐methionine (SAM)‐dependent deoxysugar methyltransferase. Their optimal activities require the presence of Mg2+. With the reconstituted in vitro assays, the order of mycinamicin VI→III→IV in the post‐PKS (polyketide synthase) tailoring pathway of mycinamicin was unambiguously determined.

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Position‐Dependent Electrostatic Protection against Protein Aggregation
Authors: Buell Alexander K. , Tartaglia Gian Gaetano , Birkett Neil R. , Waudby Christopher A. , Vendruscolo Michele , Salvatella Xavier , Welland Mark E. , Dobson Christopher M. , Knowles Tuomas P. J.
Published: May 2009

Proteins with a high propensity to aggregate can be largely prevented from doing so with surprisingly small changes to their primary structure. By using a combination of rational design and quantitative measurements of aggregation rates, we show that adding a single charge in specific “gatekeeper” regions is sufficient to change the timescale for amyloid fibril growth from minutes to weeks, thereby dramatically reducing the efficiency of this process.

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Cover Picture: Thiophene–Diazine Molecular Semiconductors: Synthesis, Structural, Electrochemical, Optical, and Electronic Structural Properties; Implementation in Organic Field‐Effect Transistors (Chem. Eur. J. 20/2009)
Authors: Ortiz Rocío Ponce , Casado Juan , Hernández Víctor , Navarrete Juan T. López , Letizia Joseph A. , Ratner Mark A. , Facchetti Antonio , Marks Tobin J.
Published: May 2009

Molecular semiconductors in the guise of three diazine‐functionalized oligothiophenes have been synthesized and their structural, optical, vibrational, electrochemical, and semiconductor properties studied. In their Full Paper on page 5023 ff., J. T. López Navarrete, A. Facchetti, T. J. Marks et al. describe how these diazine‐functionalized oligothiophenes are reasonably efficient hole transporters.

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Energieeffizient und emissionsneutral: Wasserstoff und Brennstoffzelle in der Marktvorbereitung
Authors: Bonhoff K.
Published: May 2009

Wasserstoff als Kraftstoff und die Brennstoffzelle als hocheffiziente und emissionsarme Antriebstechnologie können in Zukunft einen wertvollen Beitrag zur Schonung der Umwelt und zur Schaffung zukunftsfähiger Arbeitsplätze in Deutschland leisten. Deutschlands gute Startposition muss jetzt genutzt werden, um einen wirklichen Markt‐ und Standortvorteil zu erzielen. Der Beitrag gibt einen kurzen Überblick über Initiativen der Bundesrepublik.
Perspektiven für den Ausbau der Wasserstoffinfrastruktur am Beispiel NRW
Authors: Grube T. , Fischedick M. , Pastowski A. , Stolten D.
Published: May 2009

Die Vision einer klimafreundlichen zukünftigen energetischen Nutzung von Wasserstoff ist untrennbar mit dessen Erzeugung auf der Basis von regenerativer Energie verknüpft. Für einen Übergangszeitraum kann der Rückgriff auf anderweitig in Industrieprozessen erzeugten Wasserstoff einschließlich vorhandener Infrastrukturelemente sinnvoll sein. Nordrhein‐Westfalen bietet hierfür mit dem Rhein‐Ruhr‐Raum besonders günstige Voraussetzungen und verfügt über zahlreiche Standorte, die sich für energetische Pioniernutzungen von Wasserstoff anbieten. Der Beitrag verknüpft die Erhebung der verfügbaren Wasserstoffmengen in NRW mit der Modellierung des Aufbaus einer Wasserstoffinfrastruktur in NRW und stellt dabei die besondere Ausgangslage des Bundeslandes heraus.
Das Kompetenz‐Netzwerk Brennstoffzelle und Wasserstoff Nordrhein‐Westfalen
Authors: Ziolek Andreas
Published: May 2009

Ziel des Kompetenz‐Netzwerk Brennstoffzelle und Wasserstoff Nordrhein‐Westfalen (KNBW NRW) der EnergieAgentur.NRW mit Sitz in Düsseldorf ist die Etablierung eines neuen Wirtschaftszweiges durch die gezielte Markteinführung der Brennstoffzellentechnik sowie von Brennstoffzellensystemkomponenten in dazu geeigneten Pilotmärkten. Begleitet durch eine zielgerichtete Forschung und Entwicklung sowie den nachhaltigen Aufbau einer geeigneten Wasserstoffinfrastruktur sollen schrittweise auch die Massenmärkte im mobilen und stationären Bereich erschlossen werden. Das Netzwerk ist derzeit das größte seiner Art in Europa.
Mobile Brennstoffzellen‐Batterie‐Hybrid‐Anwendungen
Authors: Riegel B.
Published: May 2009

Die Brennstoffzelle in Kombination mit verschiedenen Hochleistungsbatterien ist eine gute Möglichkeit, die chemische Energie, die im Wasserstoff gebunden ist, für die Anwendung im Material‐Handling‐Bereich nutzbar zu machen. Ein derartiges System gestattet erstmalig eine echte Trennung zwischen der Bereitstellung von Energie in Form einer Brennstoffzelle zur Versorgung der Grundlastanforderung und von Leistung in Form einer Batterie zur Abdeckung hoher Lastspitzen und effizienter Nutzung von Rekuperationsenergien. Außerdem hat es den Vorteil, dass Mehrschichteinsätze gefahren werden können, ohne das Energieversorgungssystem wechseln zu müssen. Im Rahmen des von der Landesregierung Nordrhein‐Westfalen geförderten Projektes BBH‐MH „Brennstoffzellen‐Batterie‐Hybrid für Material Handling”︁ wurden drei Prototypen für den Einsatz in einem Klasse‐I‐ und zwei Klasse‐II‐Fahrzeugen durch die Firma HOPPECKE konzipiert, entworfen und erfolgreich in Betrieb genommen. Hierbei handelt es sich um ein 80‐V‐System für einen Gegengewichtsgabelstapler vom Typ Still R60‐25iL und zwei 48‐V‐Systeme für den Vertikalkommissionierer Still EK12i sowie den Schubmaststapler Still FM‐X20.
Neue keramische Werkstoffe für Hochtemperaturbrennstoffzellen
Authors: Stelter M. , Megel S. , Marschallek F. , Mosch S.
Published: May 2009

Keramische Hochtemperaturbrennstoffzellen (SOFC) müssen bei Temperaturen von ca. 850 °C betrieben werden, um technisch attraktive elektrische Wirkungsgrade von über 50 % zu erzielen. Die erhöhten Anforderungen an die Konstruktions‐ und Aktivmaterialien im System lassen sich durch innovative Keramiklösungen erfüllen. Beispiele werden in dieser Arbeit vorgestellt.