bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of an antiandrogenic oral contraceptive pill compared with metformin on blood coagulation tests and endothelial function in women with the polycystic ovary syndrome: influence of obesity and smoking
Authors: Luque-Ramírez Manuel , Mendieta-Azcona Covandonga , del Rey Sánchez José M , Matíes Milagro , Escobar-Morreale Héctor F 
Published: January 2009

ObjectiveTo study the blood clotting tests and endothelial function of polycystic ovary syndrome (PCOS) patients and non-hyperandrogenic women, and their changes during PCOS treatment, as a function of the presence of obesity and smoking.DesignCase-control study followed by a randomized clinical trial.MethodsBlood clotting and endothelial function were analyzed in 40 PCOS patients and 20 non-hyperandrogenic women. Thirty-four PCOS women were randomized to an oral contraceptive containing 35 μg ethinyl-estradiol plus 2 mg cyproterone acetate (Diane35Diario) or metformin (850 mg twice daily), monitoring the changes on these parameters during 24 weeks of treatment. The influence of obesity and smoking was also analyzed.ResultsBlood clotting and endothelial function tests were similar among PCOS patients and controls with the exception of a higher platelet count in the former. Obesity increased circulating fibrinogen levels, prothrombin activity and platelet counts, and reduced prothrombin and activated partial thromboplastin times. Smoking increased fibrinogen levels, platelet counts, and prothrombin activity, and reduced prothrombin time, in relation to the larger waist circumference of smokers. Irrespective of the treatment received, PCOS patients showed a decrease in prothrombin time and an increase in prothrombin activity, with a parallel increase in homocysteine levels in metformin users. The activated partial thromboplastin time decreased markedly in the patients treated with Diane35Diario. Finally, flow-mediated dilation improved in non-smokers irrespective of the drug received, but worsened in smokers.ConclusionsOral contraceptives and metformin may exert deleterious effects on blood clotting tests of PCOS women, yet the effects of metformin appear to be milder. Because smoking potentiates some of these effects and deteriorates endothelial function, smoking cessation should be promoted in PCOS patients.
Single Nucleotide Polymorphisms in the Allene Oxide Synthase 2 Gene Are Associated With Field Resistance to Late Blight in Populations of Tetraploid Potato Cultivars
Authors: Pajerowska-Mukhtar Karolina , Stich Benjamin , Achenbach Ute , Ballvora Agim , Lübeck Jens , Strahwald Josef , Tacke Eckhard , Hofferbert Hans-Reinhard , Ilarionova Evgeniya , Bellin Diana , Walkemeier Birgit , Basekow Rico , Kersten Birgit , Gebhardt Christiane 
Published: January 2009

Abstract
The oomycete Phytophthora infestans causes late blight, the most relevant disease of potato (Solanum tuberosum) worldwide. Field resistance to late blight is a complex trait. When potatoes are cultivated under long day conditions in temperate climates, this resistance is correlated with late plant maturity, an undesirable characteristic. Identification of natural gene variation underlying late blight resistance not compromised by late maturity will facilitate the selection of resistant cultivars and give new insight in the mechanisms controlling quantitative pathogen resistance. We tested 24 candidate loci for association with field resistance to late blight and plant maturity in a population of 184 tetraploid potato individuals. The individuals were genotyped for 230 single nucleotide polymorphisms (SNPs) and 166 microsatellite alleles. For association analysis we used a mixed model, taking into account population structure, kinship, allele substitution and interaction effects of the marker alleles at a locus with four allele doses. Nine SNPs were associated with maturity corrected resistance (P &lt; 0.001), which collectively explained 50% of the genetic variance of this trait. A major association was found at the StAOS2 locus encoding allene oxide synthase 2, a key enzyme in the biosynthesis of jasmonates, plant hormones that function in defense signaling. This finding supports StAOS2 as being one of the factors controlling natural variation of pathogen resistance.
Quantum‐Chemical Characterization of the Origin of Dipole Formation at Molecular Organic/Organic Interfaces
Authors: Avilov Igor , Geskin Victor , Cornil Jérôme 
Published: January 2009

AbstractRecent experiments have reported a vacuum level shift at the interface between organic materials due to the formation of an interface dipole layer. On the basis of quantum‐chemical calculations, this paper sheds light on the factors contributing to the formation of an interface dipole between an electron donor and an electron acceptor, considering as model system a complex made of tetrathiafulvalene (TTF) as a donor and tetracyanoquinodimethane (TCNQ) as an acceptor. The results indicate that the interface dipole is governed both by charge‐transfer and polarization effects and allow for disentangling of their respective contributions. Two regimes of charge transfer can be distinguished depending on the strength of the electronic coupling: a fractional charge transfer occurs in the strong coupling regime while only integer charges are transferred when the coupling is weak. The polarization contribution can be significant, even in the presence of a pronounced charge transfer between the donor and acceptor molecules. The values of ionization potential and electron affinity of the donor and acceptor molecules may experience shifts as large as several tenths of an eV at the interface with respect to the isolated compounds.
Enhancement of Carrier Mobilities of Organic Semiconductors on Sol–Gel Dielectrics: Investigations of Molecular Organization and Interfacial Chemistry Effects
Authors: Cahyadi Tommy , Kasim Johnson , Tan Huei Shuan , Kulkarni Shripad R. , Ong Beng S. , Wu Yiliang , Chen Zhi‐Kuan , Ng Chee Mang , Shen Ze‐Xiang , Mhaisalkar Subodh G. 
Published: January 2009

AbstractThe dielectric‐semiconductor interfacial interactions critically influence the morphology and molecular ordering of the organic semiconductor molecules, and hence have a profound influence on mobility, threshold voltage, and other vital device characteristics of organic field‐effect transistors. In this study, p‐channel small molecule/polymer (evaporated pentacene and spin‐coated poly(3,3‴;‐didodecylquarterthiophene) – PQT) and n‐channel fullerene derivative ({6}‐1‐(3‐(2‐thienylethoxycarbonyl)‐propyl)‐{5}‐1‐phenyl‐[5,6]‐C61 – TEPP‐C61) show a significant enhancement in device mobilities ranging from ∼6 to ∼45 times higher for all classes of semiconductors deposited on sol–gel silica gate‐dielectric than on pristine/octyltrichlorosilane (OTS)‐treated thermally grown silica. Atomic force microscopy, synchrotron X‐ray diffraction, photoluminescence/absorption, and Raman spectroscopy studies provide comprehensive evidences that sol–gel silica dielectrics‐induced enhancement in both p‐ and n‐channel organic semiconductors is attributable to better molecular ordering/packing, and hence reduced charge trapping centers due to lesser structural defects at the dielectric‐semiconductor interface.
Highly Efficient Quantum‐Dot‐Sensitized Solar Cell Based on Co‐Sensitization of CdS/CdSe
Authors: Lee Yuh‐Lang , Lo Yi‐Siou 
Published: January 2009

AbstractCadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots (QDs) are sequentially assembled onto a nanocrystalline TiO2 film to prepare a CdS/CdSe co‐sensitized photoelectrode for QD‐sensitized solar cell application. The results show that CdS and CdSe QDs have a complementary effect in the light harvest and the performance of a QDs co‐sensitized solar cell is strongly dependent on the order of CdS and CdSe respected to the TiO2. In the cascade structure of TiO2/CdS/CdSe electrode, the re‐organization of energy levels between CdS and CdSe forms a stepwise structure of band‐edge levels which is advantageous to the electron injection and hole‐recovery of CdS and CdSe QDs. An energy conversion efficiency of 4.22% is achieved using a TiO2/CdS/CdSe/ZnS electrode, under the illumination of one sun (AM1.5,100 mW cm−2). This efficiency is relatively higher than other QD‐sensitized solar cells previously reported in the literature.
Heat‐Transport Mechanisms in Superlattices
Authors: Koh Yee Kan , Cao Yu , Cahill David G. , Jena Debdeep 
Published: January 2009

AbstractThe heat transport mechanisms in superlattices are identified from the cross‐plane thermal conductivity Λ of (AlN)x–(GaN)y superlattices measured by time‐domain thermoreflectance. For (AlN)4.1 nm–(GaN)55 nm superlattices grown under different conditions, Λ varies by a factor of two; this is attributed to differences in the roughness of the AlN/GaN interfaces. Under the growth condition that gives the lowest Λ, Λ of (AlN)4 nm–(GaN)y superlattices decreases monotonically as y decreases, Λ = 6.35 W m−1 K−1 at y = 2.2 nm, 35 times smaller than Λ of bulk GaN. For long‐period superlattices (y > 40 nm), the mean thermal conductance G of AlN/GaN interfaces is independent of y, G ≈ 620 MW m−2 K−1. For y < 40 nm, the apparent value of G increases with decreasing y, reaching G ≈ 2 GW m−2 K−1 at y < 3 nm. MeV ion bombardment is used to help determine which phonons are responsible for heat transport in short period superlattices. The thermal conductivity of an (AlN)4.1 nm–(GaN)4.9 nm superlattice irradiated by 2.3 MeV Ar ions to a dose of 2 × 1014 ions cm−2 is reduced by <35%, suggesting that heat transport in these short‐period superlattices is dominated by long‐wavelength acoustic phonons. Calculations using a Debye‐Callaway model and the assumption of a boundary scattering rate that varies with phonon‐wavelength successfully capture the temperature, period, and ion‐dose dependence of Λ.
Ambipolar Organic Field‐Effect Transistors from Cross‐Conjugated Aromatic Quaterthiophenes; Comparisons with Quinoidal Parent Materials
Authors: Ortiz Rocío Ponce , Facchetti Antonio , Marks Tobin J. , Casado Juan , Zgierski Marek Z. , Kozaki Masatoshi , Hernández Víctor , Navarrete Juan T. López 
Published: January 2009

AbstractThis contribution presents an electrochemical, Raman spectroscopic, and theoretical study probing the differences in molecular and electronic structure of two quinoidal oligothiophenes (3′,4′‐dibutyl‐5,5″‐bis(dicyanomethylene)‐5,5″‐dihydro‐2,2′:5′,2″‐terthiophene and 5,5′‐bis(dicyanomethylene)‐3‐hexyl‐2,5‐dihydro‐4,4′‐dihexyl‐2,2′,5,5′‐tetrahydro‐tetrathiophene) with terminal tetracyanomethylene functionalization and aromatic oligothiophenes where acceptor moieties are positioned at lateral positions along the conjugated chain (6,6′‐dibutylsulfanyl‐[2,2′‐bi‐[4‐dicyanovinylene‐4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophene]). In this way, the consequences of linear and cross conjugation are compared and contrasted. From this analysis, it is apparent that organic field‐effect transistors fabricated with cross‐conjugated tetrathiophene semiconductors should combine the benefits of an electron‐donor aromatic chain with strongly electron‐accepting tetracyanomethylene substituents. The corresponding organic field‐effect transistors exhibit ambipolar transport with rather similar hole and electron mobilities. Moreover, n‐channel conduction is enhanced to yield one of the highest electron mobilities found to date for this type of material.
Influence of Point‐Defect Reaction Kinetics on the Lattice Parameter of Ce0.8Gd0.2O1.9
Authors: Kossoy Anna , Feldman Yishai , Korobko Roman , Wachtel Ellen , Lubomirsky Igor , Maier Joachim 
Published: January 2009

AbstractThe kinetics of point‐defect association/dissociation reactions in Ce0.8Gd0.2O1.9 and their influence on the crystal lattice parameter are investigated by monitoring thermally induced stress and strain in substrate‐ and self‐supported thin films. It is found that, in the temperature range of 100–180 °C, the lattice parameter of the substrate‐supported films and the lateral dimensions of annealed, self‐supported films both exhibit a hysteretic behavior consistent with dissociation/association of oxygen vacancy–aliovalent dopant complexes. This leads to strong deviation from linear elastic behavior, denoted in the authors' previous work as the “chemical strain” effect. At room temperature, the equilibrium state of the point defects is reached within a few months. During this period, the lattice parameter of the substrate‐supported films spontaneously increases, while the self‐supported films are observed to transform from the flat to the buckled state, indicating that formation of the dopant–vacancy complex is associated with a volume increase. The unexpectedly slow kinetics of establishing the defect equilibrium at room temperature can explain the fact that, depending on the sample history, the “observable” lattice parameters of Ce0.8Gd0.2O1.9, as reported in the literature, may differ from one another by a few tenths of a percent. These findings strongly suggest that the lattice parameter of the materials with a large concentration of interacting point defects is a strong function of time and material preparation route.
Field Emission and Cathodoluminescence of ZnS Hexagonal Pyramids of Zinc Blende Structured Single Crystals
Authors: Chen Zhi‐Gang , Zou Jin , Wang Dai‐Wei , Yin Li‐Chang , Liu Gang , Liu Qingfeng , Sun Cheng‐Hua , Yao Xiangdong , Li Feng , Yuan Xiao‐Li , Sekiguchi Takashi , Lu Gao Qing , Cheng Hui‐Ming 
Published: January 2009

AbstractSingle‐crystal hexagonal pyramids of zinc blende ZnS are fabricated by facile thermal evaporation in an ammonia atmosphere at 1150 °C. It is found that ZnS pyramids grow along the [111] crystal axis and possess a sharp tip with a diameter of ∼10 nm and a micrometer‐sized base. The structural model and growth mechanism are proposed based on crystallographic characteristics. This unique ZnS pyramid structure exhibits a low turn‐on field (2.81 V µm−1), a high field‐enhancement factor (over 3000), a large field‐emission current density (20 mA cm−2), and good stability with very small fluctuation (0.9%). These superior field‐emission properties are clearly attributed to the pyramid morphology, with micrometer‐sized bases and nanotips, and high crystallinity. Moreover, a stable UV emission of 337 nm at room temperature is observed and can be ascribed to the band emission of the zinc blende phase. These results suggest that the ZnS hexagonal pyramids can be expected to find promising applications as field emitters and optoelectronic devices.
Multifunctional Deep‐Blue Emitter Comprising an Anthracene Core and Terminal Triphenylphosphine Oxide Groups
Authors: Chien Chen‐Han , Chen Ching‐Kun , Hsu Fang‐Ming , Shu Ching‐Fong , Chou Pi‐Tai , Lai Chin‐Hung 
Published: January 2009

AbstractA highly efficient blue‐light emitter, 2‐tert‐butyl‐9,10‐bis[4′‐(diphenyl‐phosphoryl)phenyl]anthracene (POAn) is synthesized, and comprises electron‐deficient triphenylphosphine oxide side groups appended to the 9‐ and 10‐positions of a 2‐tert‐butylanthracene core. This sophisticated anthracene compound possesses a non‐coplanar configuration that results in a decreased tendency to crystallize and weaker intermolecular interactions in the solid state, leading to its pronounced morphological stability and high quantum efficiency. In addition to serving as an electron‐transporting blue‐light‐emitting material, POAn also facilitates electron injection from the Al cathode to itself. Consequently, simple double‐layer devices incorporating POAn as the emitting, electron‐transporting, and ‐injecting material produce bright deep‐blue lights having Commission Internationale de L'Eclairage coordinates of (0.15,0.07). The peak electroluminescence performance was 4.3% (2.9 cd A−1). For a device lacking an electron‐transport layer or alkali fluoride, this device displays the best performance of any such the deep‐blue organic light‐emitting diodes reported to date.
Temperature‐Sensitive Nanocapsules for Controlled Drug Release Caused by Magnetically Triggered Structural Disruption
Authors: Liu Ting‐Yu , Liu Kun‐Ho , Liu Dean‐Mo , Chen San‐Yuan , Chen I‐Wei 
Published: January 2009

AbstractSelf‐assembled nanocapsules containing a hydrophilic core and a crosslinked yet thermosensitive shell are successfully prepared using poly(ethylene‐oxide)‐poly(propylene‐oxide)‐poly(ethylene‐oxide) block copolymers, 4‐nitrophenyl chloroformate, gelatin, and 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide. The core is further rendered magnetic by incorporating iron oxide nanoparticles via internal precipitation to enable externally controlled actuation under magnetic induction. The spherical nanocapsules exhibit a hydrophilic‐to‐hydrophobic transition at a characteristic but tunable temperature reaching 40 °C, triggering a size contraction and shrinkage of the core. The core content experiences very little leakage at 25 °C, has a half life about 5 h at 45 °C, but bursts out within a few minutes under magnetic heating due to iron oxide coarsening and core/shell disruption. Such burst‐like response may be utilized for controlled drug release as illustrated here using a model drug Vitamin B12.
Highly Efficient Red Phosphorescent OLEDs based on Non‐Conjugated Silicon‐Cored Spirobifluorene Derivative Doped with Ir‐Complexes
Authors: Lyu Yi‐Yeol , Kwak Jeonghun , Jeon Woo Sung , Byun Younghun , Lee Hyo Sug , Kim Doseok , Lee Changhee , Char Kookheon 
Published: January 2009

AbstractA novel host material containing silicon‐cored spirobifluorene derivative (SBP‐TS‐PSB), is designed, synthesized, and characterized for red phosphorescent organic light‐emitting diodes (OLEDs). The SBP‐TS‐PSB has excellent thermal and morphological stabilities and exhibits high electroluminescence (EL) efficiency as a host for the red phosphorescent OLEDs. The electrophosphorescence properties of the devices using SBP‐TS‐PSB as the host and red phosphorescent iridium (III) complexes as the emitter are investigated and these devices exhibit higher EL performances compared with the reference devices with 4,4′‐N,N′‐dicarbazole‐biphenyl (CBP) as a host material; for example, a (piq)2Ir(acac)‐doped SBP‐TS‐PSB device shows maximum external quantum efficiency of ηext = 14.6%, power efficiency of 10.3 lm W−1 and Commission International de L'Eclairage color coordinates (0.68, 0.32) at J = 1.5 mA cm−2, while the device with the CBP host shows maximum ηext = 12.1%. These high performances can be mainly explained by efficient triplet energy transfer from the host to the guests and improved charge balance attributable to the bipolar characteristics of the spirobifluorene group.
Ordered Mesoporous In2O3: Synthesis by Structure Replication and Application as a Methane Gas Sensor
Authors: Waitz Thomas , Wagner Thorsten , Sauerwald Tilman , Kohl Claus‐Dieter , Tiemann Michael 
Published: January 2009

AbstractThe synthesis and characterization of ordered mesoporous In2O3 materials by structure replication from hexagonal mesoporous SBA‐15 silica and cubic KIT‐6 silica is presented. Variation of the synthesis parameters allows for different pore sizes and pore wall thicknesses in the products. The In2O3 samples turn out to be stable up to temperatures between 450 °C and 650 °C; such high thermal stability is necessary for their application as gas sensors. Test measurements show a high sensitivity to methane gas in concentrations relevant for explosion prevention. The sensitivity is shown to be correlated not only with the surface‐to‐volume ratio, but also with the nanoscopic structural properties of the materials.
High‐Performance SOFC Cathodes Prepared by Infiltration
Authors: Vohs John M. , Gorte Raymond J. 
Published: January 2009

AbstractImproved cathodes are required for low‐temperature operation of solid‐oxide fuel cells (SOFCs). Recent work has shown that electrode fabrication and modification by infiltration of active components into a porous scaffold can result in outstanding electrochemical performance. In this paper we review the literature on this new approach for cathode preparation and discuss the insights that this work has provided for understanding the relationships between the materials properties, electrochemical performance, and electrode stability.
Retraction: An Efficient Synthesis of Poly(ethylene glycol)‐Supported Iron(II) Porphyrin using a Click Reaction and its Application for the Catalytic Olefination of Aldehydes
Authors: Jain Suman L. , Joseph Jomy K. , Kühn Fritz E. , Reiser Oliver 
Published: January 2009

AbstractThe first successful synthesis of poly(ethylene glycol) (PEG) immobilized iron(II) porphyrin using a copper‐catalyzed azide‐alkyne [3+2] cycloaddition is reported. In contrast to the existing methods for the synthesis of PEG‐immobilized metalloporphyrins, the click method offers better catalyst loading under comparatively mild reaction conditions. The prepared complex 5 (PEG‐C51H39FeN7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine and afforded excellent olefin yields with high (E) selectivities. The PEG‐supported catalyst 5 was readily recovered by precipitation and filtration and was recycled for up to ten runs without significant loss of activity.
The First Thiadiazolidine 1‐Oxide System for Phosphine‐Free Palladium‐Mediated Catalysis
Authors: Buckley Benjamin R. , Neary Stephen P. 
Published: January 2009

AbstractWe herein report a highly active catalyst system using for the first time a thiadiazolidine 1‐oxide as a ligand for palladium in the Mizoroki–Heck reaction. Excellent yields of stilbenes derived from aryl iodides and bromides have been achieved using as little as 0.00002 mol% catalyst. The ligand/palladium system can be stored as a stock solution open to air at room temperature with no observable loss of activity for a period of several weeks/months.
Selective Oxidation of Aromatic Amines to Nitro Derivatives using Potassium Iodide‐tert‐Butyl Hydroperoxide Catalytic System
Authors: Reddy K. Rajender , Maheswari C. Uma , Venkateshwar M. , Kantam M. Lakshmi 
Published: January 2009

AbstractThe direct oxidation of aromatic primary amines to the corresponding nitro compounds selectively in 47–98% yields has been achieved by using potassium iodide as catalyst and tert‐butyl hydroperoxide as the external oxidant. The present catalytic system works well for both electron‐rich and electron‐poor substrates.
Kinetic Resolutions by Enantioselective Pauson–Khand‐Type Reaction
Authors: Kim Dong Eun , Kwak Jaesung , Kim In Su , Jeong Nakcheol 
Published: January 2009

AbstractA kinetic resolution of 1‐arylallyl propargyl ethers by enantioselective Pauson–Khand‐type reaction catalysts was successfully carried out. While cationic rhodium(I) with a BINAP‐based ligand having an electron‐deficient phosphine is the choice for the slow reacting substrates, neutral iridium(I) with a BINAP‐based ligand possessing an electron‐rich phosphine provided excellent results for the more reactive substrates.
Lewis Acid‐Mediated Selective Cycloadditions of Vinylidenecyclopropanes with Aromatic Aldehydes: An Efficient Protocol for the Synthesis of Benzo[c]fluorene, Furan and Furo[2,3‐b]furan Derivatives
Authors: Su Chenliang , Huang Xian 
Published: January 2009

AbstractThree kinds of Lewis acid‐mediated reactions of vinylidenecyclopropanes and aromatic aldehydes are disclosed in this paper, providing an efficient and selective synthesis of a variety of functionalized benzo[c]fluorene, furan and furo[2,3‐b]furan derivatives.
Water in Stereoselective Organocatalytic Reactions
Authors: Gruttadauria Michelangelo , Giacalone Francesco , Noto Renato 
Published: January 2009

AbstractIn this review, recent advances in asymmetric organocatalytic reactions carried out with variable amounts of water, from substoichiometric to a large excess (reaction medium), are discussed. We also summarize several proposed mechanisms for the different possibilities of the action of water both in the increased activity of the catalyst and in the asymmetric induction. Finally, the application of this catalytic methodology to the enantioselective synthesis of valuable compounds through enamine or iminium catalysis is presented.