bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐Assembled Graphene–Enzyme Hierarchical Nanostructures for Electrochemical Biosensing
Authors: Zeng Qiong , Cheng Jinsheng , Tang Longhua , Liu Xiaofei , Liu Yanzhe , Li Jinghong , Jiang Jianhui 
Published: August 2010

AbstractThe self‐assembly of sodium dodecyl benzene sulphonate (SDBS) functionalized graphene sheets (GSs) and horseradish peroxidase (HRP) by electrostatic attraction into novel hierarchical nanostructures in aqueous solution is reported. Data from scanning electron microscopy, high‐resolution transmission electron microscopy, and X‐ray diffraction demonstrate that the HRP–GSs bionanocomposites feature ordered hierarchical nanostructures with well‐dispersed HRP intercalated between the GSs. UV‐vis and infrared spectra indicate the native structure of HRP is maintained after the assembly, implying good biocompatibility of SDBS‐functionalized GSs. Furthermore, the HRP–GSs composites are utilized for the fabrication of enzyme electrodes (HRP–GSs electrodes). Electrochemical measurements reveal that the resulting HRP–GSs electrodes display high electrocatalytic activity to H2O2 with high sensitivity, wide linear range, low detection limit, and fast amperometric response. These desirable electrochemical performances are attributed to excellent biocompatibility and superb electron transport efficiency of GSs as well as high HRP loading and synergistic catalytic effect of the HRP–GSs bionanocomposites toward H2O2. As graphene can be readily non‐covalently functionalized by “designer” aromatic molecules with different electrostatic properties, the proposed self‐assembly strategy affords a facile and effective platform for the assembly of various biomolecules into hierarchically ordered bionanocomposites in biosensing and biocatalytic applications.
Autonomic Recovery of Fiber/Matrix Interfacial Bond Strength in a Model Composite
Authors: Blaiszik Benjamin J. , Baginska Marta , White Scott R. , Sottos Nancy R. 
Published: August 2010

AbstractAutonomic self‐healing of interfacial damage in a model single‐fiber composite is achieved through sequestration of ca. 1.5 μm diameter dicyclopentadiene (DCPD) healing‐agent‐filled capsules and recrystallized Grubbs’ catalyst to the fiber/matrix interface. When damage initiates at the fiber/matrix interface, the capsules on the fiber surface rupture, and healing agent is released into the crack plane where it contacts the catalyst, initiating polymerization. A protocol for characterizing the efficiency of interfacial healing for the single‐fiber system is established. Interfacial shear strength (IFSS), a measure of the bond strength between the fiber and matrix, is evaluated for microbond specimens consisting of a single self‐healing functionalized fiber embedded in a microdroplet of epoxy. The initial (virgin) IFSS is equivalent or enhanced by the addition of capsules and catalyst to the interface and up to 44% average recovery of IFSS is achieved in self‐healing samples after full interfacial debonding. Examination of the fracture interfaces by scanning electron microscopy reveals further evidence of a polyDCPD film in self‐healing samples. Recovery of IFSS is dictated by the bond strength of polyDCPD to the surrounding epoxy matrix.
Effects of Thermal Annealing Upon the Morphology of Polymer–Fullerene Blends
Authors: Verploegen Eric , Mondal Rajib , Bettinger Christopher J. , Sok Seihout , Toney Michael F. , Bao Zhenan 
Published: August 2010

AbstractGrazing incidence X‐ray scattering (GIXS) is used to characterize the morphology of poly(3‐hexylthiophene) (P3HT)–phenyl‐C61‐butyric acid methyl ester (PCBM) thin film bulk heterojunction (BHJ) blends as a function of thermal annealing temperature, from room temperature to 220 °C. A custom‐built heating chamber for in situ GIXS studies allows for the morphological characterization of thin films at elevated temperatures. Films annealed with a thermal gradient allow for the rapid investigation of the morphology over a range of temperatures that corroborate the results of the in situ experiments. Using these techniques the following are observed: the melting points of each component; an increase in the P3HT coherence length with annealing below the P3HT melting temperature; the formation of well‐oriented P3HT crystallites with the (100) plane parallel to the substrate, when cooled from the melt; and the cold crystallization of PCBM associated with the PCBM glass transition temperature. The incorporation of these materials into BHJ blends affects the nature of these transitions as a function of blend ratio. These results provide a deeper understanding of the physics of how thermal annealing affects the morphology of polymer–fullerene BHJ blends and provides tools to manipulate the blend morphology in order to develop high‐performance organic solar cell devices.
An Organic Hole Transport Layer Enhances the Performance of Colloidal PbSe Quantum Dot Photovoltaic Devices
Authors: Kuo Chih‐Yin , Su Ming‐Shin , Hsu Yu‐Chien , Lin Hui‐Ni , Wei Kung‐Hwa 
Published: August 2010

AbstractA thin poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hole transport layer enhances the AM1.5 power conversion efficiency of a PbSe quantum dot (QD)–containing photovoltaic device to 2.4%, from 1.5% for a standard PbSe QD device, a relative increase of 60%. Synchrotron X‐ray reflectivity measurements reveal that the roughness of the interfaces between the various layers decreases dramatically in the presence of the PEDOT:PSS layer. In addition, the device life time under continuous simulated AM1.5 irradiation (100 mW cm−2), measured in terms of the time required to reach 80% of the normalized efficiency, for the PbSe QD device incorporating the PEDOT:PSS hole transport layer is six times longer than that of the standard PbSe QD device.
Layer‐by‐Layer All‐Inorganic Quantum‐Dot‐Based LEDs: A Simple Procedure with Robust Performance
Authors: Bendall James S. , Paderi Marzia , Ghigliotti Francesca , Li Pira Nello , Lambertini Vitoguido , Lesnyak Vladimir , Gaponik Nikolai , Visimberga Giuseppe , Eychmüller Alexander , Torres Clivia M. Sotomayor , Welland Mark E. , Gieck Christina , Marchese Leonardo 
Published: August 2010

AbstractA novel all‐inorganic electroluminescent device is demonstrated based on highly luminescent CdTe nanocrystals intercalated within a laminar hydrotalcite‐like structure. The laminar scaffold acts to both support and distribute the CdTe nanocrystals. The device is synthesized using simple wet chemical processes at room temperature in ambient conditions. It has high thermal stability, operating continuously up to 90 °C, and a maximum efficiency at J = 0.12 A cm−2. The device is targeted at the automotive industry.
Cyclopalladated Ferrocenylimine as Efficient Catalyst for the Syntheses of Arylboronate Esters
Authors: Wang Lianhui , Li Jingya , Cui Xiuling , Wu Yusheng , Zhu Zhiwu , Wu Yangjie 
Published: August 2010

AbstractThe cyclopalladated ferrocenylimine I and its phosphine adducts IIa–f were prepared and evaluated in the borylation of aryl halides. The tricyclohexylphosphine adduct IIb exhibited highly catalytic activity for the coupling of aryl and heteroaryl bromides containing various functional groups with low catalyst loading (2 mol%). Aryl and heteroaryl chlorides were smoothly converted into the corresponding boronates in the presence of the monophosphinobiaryl ligand (XPhos) adduct IIf. It was proposed that palladacycle was only a reservoir of the catalytically active species from the investigation on the reaction mechanism.
Highly Chemo‐ and Regioselective Reduction of Aromatic Nitro Compounds Catalyzed by Recyclable Copper(II) as well as Cobalt(II) Phthalocyanines
Authors: Sharma Upendra , Kumar Praveen , Kumar Neeraj , Kumar Vishal , Singh Bikram 
Published: August 2010

AbstractCopper/cobalt phthalocyanines were established for the first time as catalysts for the very efficient chemo‐ and regioselective reduction of aromatic nitro compounds to generate the corresponding amines. The selective reduction of nitro compounds was observed in the presence of a large range of functional groups such as aldehyde, keto, acid, amide, ester, halogen, lactone, nitrile and heterocyclic functional groups. Furthermore, the present method was found to be highly regioselective towards the reduction of aromatic dinitro compounds in a short time with high yields. In most of the cases the conversion and selectivity were >99% as monitored by GC‐MS. The reduction mechanism was elucidated by UV‐vis and electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry.
Enantioselective Copper‐Catalysed Allylic Alkylation of Cinnamyl Chlorides by Grignard Reagents using Chiral Phosphine‐Phosphite Ligands
Authors: Lölsberg Wibke , Ye Shute , Schmalz Hans‐Günther 
Published: August 2010

AbstractThe copper(I)‐catalysed SN2′‐type allylic substitution of E‐3‐aryl‐allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine‐phosphite ligands a new copper(I)‐based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio‐ and enantioselectivity. Best results were obtained using TADDOL‐derived ligands (3 mol%), copper(I) bromide⋅dimethyl sulfide (CuBr⋅SMe2) (2.5 mol%) and methyl tert‐butyl ether (MTBE) as a solvent. Various (1‐alkyl‐allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho‐substituted substrates). Both electron‐rich and electron‐deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr⋅SMe2 (2.5 mol%) in the presence of triphenyl phosphine (PPh3) (3 mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho‐diphenylphosphanyl‐arylphosphite ligand with an additional phenyl substituent in ortho′‐position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl‐, n‐butyl‐, isopropyl‐, and 3‐butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho′‐position. The method was tested on a multi‐mmol scale and is suited for application in natural product synthesis.
Enantioselective Organocatalytic Transfer Hydrogenation of α‐Imino Esters by Utilization of Benzothiazoline as Highly Efficient Reducing Agent
Authors: Zhu Chen , Akiyama Takahiko 
Published: August 2010

AbstractBenzothiazoline was employed as an efficient and versatile reducing agent for the chiral phosphoric acid‐catalyzed transfer hydrogenation of α‐imino esters. The corresponding α‐amino esters were furnished with excellent enantioselectivities. Novel and readily removable benzothiazolines bearing a hydroxy group were also investigated.
A New Autocatalytic Thioacetate‐Enal Addition Reaction: A Michael Addition or Not?
Authors: Ilyashenko Gennadiy , Whiting Andrew , Wright Allen 
Published: August 2010

AbstractRather than proceeding through a Michael‐type or 1,4‐addition, thioacetic acid adds across unsaturated aldehydes in an autocatalytic manner and involving a double exotherm, as demonstrated by both adiabatic and reaction calorimetry. NMR studies show that an intermediate acylthio‐hemiacetal is involved and that the product continues to react competitively with thioacetic acid.
Recommended levels and intensities of physical activity to avoid low‐cardiorespiratory fitness in European adolescents: The HELENA study
Authors: Martinez‐Gomez David , Ruiz Jonatan R. , Ortega Francisco B. , Casajús Jose A. , Veiga Oscar L. , Widhalm Kurt , Manios Yannis , Béghin Laurent , González‐Gross Marcela , Kafatos Anthony , España‐Romero Vanesa , Molnar Denes , Moreno Luis A. , Marcos Ascension , Castillo Manuel J. , Sjöström Michael ,   on behalf of the HELENA study group
Published: August 2010

AbstractObjectives:The purpose of this study was to determine the sex‐specific physical activity (PA) intensity thresholds that best discriminate between unhealthy/healthy cardiorespiratory fitness (CRF).Methods: Participants included 1,808 adolescents (964 girls), aged 12.5–17.5 years, from the HELENA study. We measured PA by accelerometer and calculated the time spent at light, moderate, vigorous, and moderate‐to‐vigorous (MVPA) intensities. CRF was assessed by the 20‐m shuttle‐run test. Adolescents were dichotomized (unhealthy/healthy) based on sex‐ and age‐specific FITNESSGRAM standards. Receiver operating characteristic (ROC) analysis was used to determine thresholds that best discriminate between CRF categories.Results: ROC analyses revealed that the PA thresholds that best discriminate between unhealthy/healthy CRF were ≥152, ≥33, ≥13, and ≥52 min/day in light, moderate, vigorous, and MVPA, respectively. In boys, the PA thresholds associated with a healthy CRF were ≥37, ≥19, and ≥56 min/day in moderate, vigorous, and MVPA, respectively, whereas in girls were ≥152, ≥34, ≥12, and ≥51 min/day in light, moderate, vigorous, and MVPA, respectively. Spending at least 60 min/day in MVPA was also associated with a healthy CRF (odds ratios: 1.75, 1.94, and 1.57, all P < 0.05, for the whole sample, boys, and girls, respectively).Conclusions: This study shows sex‐ and intensity‐specific PA thresholds to discriminate between adolescents with a healthy CRF from those with a less favorable or unhealthy CRF level. Journal of Hospital Medicine. Society of Hospital Medicine. Am. J. Hum. Biol., 2010. © 2010 Wiley‐Liss, Inc.
Nonmetric cranial variation of Jomon Japan: Implications for the evolution of eastern Asian diversity
Authors: Nakashima Atsushi , Ishida Hajime , Shigematsu Masahito , Goto Masaaki , Hanihara Tsunehiko 
Published: August 2010

AbstractObjectivesThe purpose of this study is to investigate the origin and expansion of the Jomon population, the Neolithic inhabitants of the Japanese archipelago, and peopling East/Northeast Asian region through a global comparison between the prehistoric samples from around the world.MethodsR‐matrix approach was applied to 20 nonmetric cranial traits for assessing the population structure and history of the Jomon. Pattern of ancient group relationships on a global scale was presented using network splitstree applied to distance matrix transformed from the R‐matrix.ResultsThe phenotypic variation is largest in Hokkaido region, followed by the regions of eastern Japan. The Chugoku region, the southwestern part of Japan, shows larger variance than eastern Japan. Global analyses including samples from Northeast Asia, Southeast Asia, Australia, West Asia, Europe, and North Africa dating roughly to the same chronological periods as those of the Jomon groups, indicate northern affinities of the Jomon and the distinction between Southeast and Northeast Asian series.ConclusionThe Jomon ancestors of the northern part of Japan might have expanded southward to Honshu Island with a series of bottlenecks. A possible gene flow from outside source or heterogeneous origin of western Jomon group was, at the same time, suggested. The network relationships of the Jomon with Northeast Asians and, to a lesser extent, with Southeast Asians based on the splitstree analysis may allow us to suppose that the Jomon may be one of the key populations for the studies of the evolution of eastern Asian diversity. Am. J. Hum. Biol., 2010. © 2010 Wiley‐Liss, Inc.
Technical note: Enhancement of Scott's molar wear scoring method
Authors: Shykoluk Natalie L. , Lovell Nancy C. 
Published: August 2010

AbstractA method is described for orienting maxillary and mandibular molars in order to standardize the reporting of wear scores on quadrants of the occlusal surfaces (Scott: Am J Phys Anthropol 51 (1979) 213–217). The method, which was developed on an archeological sample from ancient Mendes, Egypt, further requires that quadrant scores be reported individually and sequentially for each tooth, rather than summed, in order to identify more easily differential and directional wear patterns. Intraobserver and interobserver error was found to be negligible when the appropriate diagrams and instructions were consulted. Thus, observer error does not add further to the potential for error associated with Scott's original scoring method. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.
Reconstructing the population history of Nicaragua by means of mtDNA, Y‐chromosome STRs, and autosomal STR markers
Authors: Nuñez Carolina , Baeta Miriam , Sosa Cecilia , Casalod Yolanda , Ge Jianye , Budowle Bruce , Martínez‐Jarreta Begoña 
Published: August 2010

AbstractBefore the arrival of the Spaniards in Nicaragua, diverse Native American groups inhabited the territory. In colonial times, Native Nicaraguan populations interacted with Europeans and slaves from Africa. To ascertain the extent of this genetic admixture and provide genetic evidence about the origin of the Nicaraguan ancestors, we analyzed the mitochondrial control region (HVSI and HVSII), 17 Y chromosome STRs, and 15 autosomal STRs in 165 Mestizo individuals from Nicaragua. To carry out interpopulation comparisons, HVSI sequences from 29 American populations were compiled from the literature. The results reveal a close relationship between Oto‐manguean, Uto‐Aztecan, Mayan groups from Mexico, and a Chibchan group to Nicaraguan lineages. The Native American contribution to present‐day Nicaraguan Mestizos accounts for most of the maternal lineages, whereas the majority of Nicaraguan Y chromosome haplogroups can be traced back to a West Eurasian origin. Pairwise Fst distances based on Y‐STRs between Nicaragua and European, African and Native American populations show that Nicaragua is much closer to Europeans than the other populations. Additionally, admixture proportions based on autosomal STRs indicate a predominantly Spanish contribution. Our study reveals that the Nicaraguan Mestizo population harbors a high proportion of European male and Native American female substrate. Finally, the amount of African ancestry is also interesting, probably because of the contribution of Spanish conquerors with NorthAfrican genetic traces or that of West African slaves. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.
Age and individual foraging behavior predict tooth wear in Amboseli baboons
Authors: Galbany Jordi , Altmann Jeanne , Pérez‐Pérez Alejandro , Alberts Susan C. 
Published: August 2010

AbstractTeeth represent an essential component of the foraging apparatus for any mammal, and tooth wear can have significant implications for survival and reproduction. This study focuses on tooth wear in wild baboons in Amboseli, southern Kenya. We obtained mandibular and maxillary tooth impressions from 95 baboons and analyzed digital images of replicas made from these impressions. We measured tooth wear as the percent dentine exposure (PDE, the percent of the occlusal surface on which dentine was exposed), and we examined the relationship of PDE to age, behavior, and life history variables. We found that PDE increased significantly with age for both sexes in all three molar types. In females, we also tested the hypotheses that long‐term patterns of feeding behavior, social dominance rank, and one measure of maternal investment (the cumulative number of months that a female had dependent infants during her lifetime) would predict tooth wear when we controlled for age. The hypothesis that feeding behavior predicted tooth wear was supported. The percent of feeding time spent consuming grass corms predicted PDE when controlling for age. However, PDE was not associated with social dominance rank or maternal investment. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.
Halbleitergassensoren: Trockensynthese und Anwendung
Authors: Tricoli Antonio , Righettoni Marco , Teleki Alexandra 
Published: August 2010

AbstractSeit der Entwicklung erster Chemiresistorgassensoren auf Metalloxidbasis wurden Wandler mit neuartigen Eigenschaften durch Nass‐ und Trockenabscheidung erzeugt. Der Direktaufbau nanostrukturierter Filme aus der Gasphase verspricht dabei eine einfache Herstellung und Steuerbarkeit, und mit geeigneten Synthese‐ und Abscheidungsmethoden können nm‐ bis μm‐dicke Filme hergestellt werden. Dichte Strukturen werden durch chemische oder Dampfabscheidungsverfahren unter kontrollierten Bedingungen erzeugt, Nanopartikelfilme durch Abscheidung mono‐ oder polydisperser, aggregierter oder agglomerierter Nanopartikel aus einem Gas. Durch schlagartiges Abkühlen während der Synthese lassen sich neuartige Materialien in Nichtgleichgewichts‐ oder substöchiometrischen Zuständen einfangen. Dieser Aufsatz beschreibt die gängigsten Verfahren für die Herstellung von Metalloxid‐Halbleiterdetektoren für chemische Gassensoren. Außerdem wird die Synthese hochporöser Filme mit neuentwickelten Aerosoltechniken diskutiert. Die chemischen und Struktureigenschaften werden der erhaltenen Sensorleistung gegenübergestellt.
Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions
Authors: Antoniotti Sylvain , Dalla Vincent , Duñach Elisabet 
Published: August 2010

AbstractDer steigende Bedarf an neuen selektiven und umweltverträglichen Methoden in der organischen Synthese treibt die Entwicklung effizienterer Reaktionssysteme an. In diesem Zusammenhang hat man sich häufig auf Übergangsmetalle, Liganden und Additive konzentriert; dem Gegenion des Metallkations wurde weniger Aufmerksamkeit geschenkt. Kürzlich wurden Metallsalze mit einem oder mehreren Triflimidat‐Gegenion(en) (Tf2N−) beschrieben. Triflimidate bilden eine einzigartige Katalysatorklasse mit außergewöhnlicher σ‐ und π‐Lewis‐Acidität, die durch die starke Delokalisierung der Ladung im Triflimidation sowie seine sterische Hinderung begründet wird. Daher wird praktisch kein nucleophiles Verhalten und eine hohe positive Ladungsdichte am Metallkation beobachtet, die seine Lewis‐Acidität verstärkt. Folglich sind Metalltriflimidate häufig effizienter als entsprechende ‐halogenide oder ‐triflate. Dieser Aufsatz beschreibt Methoden zur Herstellung von Metalltriflimidaten und deren Einsatz als Katalysatoren.
Bausteine mit Hohlräumen in supramolekularen Gelen
Authors: Foster Jonathan A. , Steed Jonathan W. 
Published: August 2010

AbstractDer Einsatz supramolekularer Gelatoren mit Hohlräumen eröffnet eine Reihe von Möglichkeiten, die bei anderen Gelsystemen nicht zur Verfügung stehen. Mit der bekannten Wirt‐Gast‐Chemie von Cavitanden können Gelstrukturen auf‐ und abgebaut, reaktionsfähige Funktionalitäten eingeführt und die Selektivität bei Anwendungen wie Katalyse oder Extraktion potenziell verbessert werden. Gelatoren mit Hohlräumen zeigen beispielhaft, wie verschiedene Aspekte der supramolekularen Chemie verwendet werden können, um gezielt reaktionsfähige Materialien herzustellen.
Koordination und Dehydrierung von Amin‐Boran‐Addukten an Metallzentren
Authors: Alcaraz Gilles , Sabo‐Etienne Sylviane 
Published: August 2010

AbstractZahlreiche Untersuchungen haben sich in jüngster Zeit mit der katalytischen Dehydrierung von Amin‐Boran‐Addukten beschäftigt, die als eine potenzielle Diwasserstoff‐Speicherform angesehen werden. Dabei wurden in katalytischen und stöchiometrischen Umsetzungen beachtliche Fortschritte erzielt. In diesem Kurzaufsatz werden die Koordination von Amin‐Boran‐Addukten an Metallzentren und mögliche Folgereaktionen diskutiert, wobei ein besonderes Augenmerk auf der B‐H‐Aktivierung liegt. Wir stellen die wenigen Beispiele vor, in denen ein Dehydrierungsprodukt in koordinierter Form beobachtet werden konnte. Dies schließt auch die Koordination von Aminoboran ein, das unter Abspaltung von Diwasserstoff aus Ammoniak‐Boran entsteht.