bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproducibility of Acute Mountain Sickness in Children and Adults: A Prospective Study
Authors: Rexhaj Emrush , Garcin Sophie , Rimoldi Stefano F. , Duplain Hervé , Stuber Thomas , Allemann Yves , Sartori Claudio , Scherrer Urs 
Published: May 2011

OBJECTIVE:
Although a history of previous acute mountain sickness (AMS) is commonly used for providing advice and recommending its prophylaxis during subsequent exposure, the intraindividual reproducibility of AMS during repeated high-altitude exposure has never been examined in a prospective controlled study.

METHODS:
In 27 nonacclimatized children and 29 adults, AMS was assessed during the first 48 hours after rapid ascent to 3450 m on 2 consecutive occasions 9 to 12 months apart.

RESULTS:
During the first exposure, 18 adults (62%) and 6 children (22%) suffered from AMS; during the second exposure, 14 adults (48%) and 4 children (15%) suffered from this problem (adults versus children, P ≤ .01). Most importantly, the intraindividual reproducibility of AMS was very different (P &lt; .001) between children and adults. None of the 6 children having suffered from AMS during the first exposure suffered from AMS during the second exposure, but 4 children with no AMS during the first exposure did experience this problem during the second exposure. In contrast, 14 of the 18 adults who suffered from AMS on the first occasion also presented with this problem during the second exposure, and no new case developed in those who had not experienced AMS on the first occasion.

CONCLUSIONS:
In adults, a history of AMS is highly predictable of the disease on subsequent exposure, whereas in children it has no predictive value. A history of AMS should not prompt practitioners to advise against reexposure to high altitude or to prescribe drugs for its prophylaxis in children.
End-Grafted Semiconducting Polymer—Candidate for Molecular Wire
Authors: Furukawa Kazuaki , Ebata Keisuke , Fujiki Michiya 
Published: May 2011

ABSTRACTWe report on polysilane, a synthetically accessible μ-conjugated silicon-catenated polymer with such semiconducting properties as photoconductivity, high hole drift mobility, and electroluminescence, as a candidate for molecular wire. We apply the “end-graft” technique, which we developed for fixing individual polymer chains on a substrate surface, to a semiflexible polysilane. The end-grafted semiflexible polysilane extended more than 500 nm across the Si(111) surface, and was clearly observed by means of atomic force microscopy (AFM).
Transport Measurements of Individual Bi Nanowires
Authors: Cronin Stephen B. , Lin Yu Ming , Koga Takaaki , Ying Jackie Y. , Dresselhaus Mildred S. 
Published: May 2011

ABSTRACTTransport properties are reported for Bi nanowires, prepared by the filling of an alumina template with molten Bi. The temperature dependence of the resistance is presented for such arrays of Bi nanowires with diameters in the 40 to 200nm range. The data are understood qualitatively on the basis of a model for a quantum-confined system. Finally, a 4-point measurement is performed on an individual Bi nanowire prepared by using an electron beam lithography technique. Techniques for handling the practical issues of non-ohmic contacts and wire burn-out are given. The physical significance of the final results of the measurements are discussed in light of various scattering mechanisms in the nanowire.
Nanoscale Patterns of Metal Nanoparticles Chemically-Assembled on Biomolecular Scaffolds: Assembly, Stability and Electron Transport Properties
Authors: Hutchison James E. , Brown Leif O. , Mooster Jana L. , Reed Scott M. , Schmidt Mary E. , Clarke Laura I. , Wybourne Martin N. 
Published: May 2011

ABSTRACTA wet chemical approach to preparing one- and two-dimensional arrays of gold nanoparticles assembled onto a polypeptide (poly-L-lysine) scaffold layer is reported. The electrical properties of biopolymer templated and nontemplated gold nanoparticle samples are compared. The electrical response of nontemplated samples is unstable, likely due to nanoparticle mobility. Biopolymer templating provides a simple, chemical method to immobilize the particles and is found to stabilize the electrical response (Coulomb blockade) of the array. A striking feature of the electrical properties is that the electron transport properties are dominated by transport through one-dimensional chains within the sample. Structural studies by AFM and XPS support the transport findings and provide evidence for the formation of one-dimensional assemblies within the arrays.
Unimolecular Electrical Rectification Down to 105 K, and Spectroscopy of Hexadecylquinolinium Tricyanoquinodimethanide
Authors: Metzger R. M. 
Published: May 2011

ABSTRACTA Langmuir-Blodgett monolayer of γ-(n-hexadecyl)quinolinum tricyanoquinodimethanide, C16H33Q-3CNQ (1), sandwiched between Al electrodes, shows asymmetric DC electrical conductivity between 370 K and 105 K. The enhanced forward current is attributable to rectification of electrical current by a single molecule, and is explained by an electronic transition from a high-moment zwitterionic ground state to a low-moment undissociated first excited state.
Room Temperature Single Electron Charging in Gold Nanoparticle Networks Formed on Biopolymer Templates
Authors: Wybourne M.N. , Clarke L. , Berven C.A. , Hutchison J.E. , Brown L.O. , Mooster J.L. 
Published: May 2011

ABSTRACTWe report the current-voltage characteristics of gold nanoparticle – biopolymer networks at room temperature. Above a threshold voltage the current-voltage relationship is almost linear. From the current-voltage scaling above threshold we argue that one-dimensional regions of the network dominate the transport. Periodic features in the conductance are found in many samples. Both the threshold voltage and the conductance features occur at voltages much greater than expected for the capacitance of the nanoparticles. Possible explanations for the structure are considered.
Room Temperature Negative Differential Resistance in Nanoscale Molecular
Authors: Chen J. , Wang W. , Reed M. A. , Rawlett A. M. , Price D. W. , Tour J. M. 
Published: May 2011

ABSTRACTMolecular devices utilizing active self-assembled monolayer (SAM) (containing nitroamine (2′-amino-4-ethynylphenyl-4′-ethynylphenyl-5′-nitro-1-benzenethiolate) and nitro (4-ethynylphenyl-4′-ethynylphenyl-2′-nitro-1-benzenethiolate) redox center) as the active component are reported. Current-voltage measurements of the devices exhibited negative differential resistance at room temperature and an on-off peak-to-valley ratio in excess of 1000:1 at low temperature.
Molecular Scale Electronics
Authors: Rawlett A. M. , Mickelson E. T. , Reinerth W. A. , Jones L. , Kozaki M. , Burgin T. P. , Tour J. M. , Chen J. , Zhou C.-W. , Muller C. J. , Deshpande M. R. , Reed M. A. , Bumm L. A. , Cygan M. T. , Dunbar T. D. , Weiss P. S. , Allara D. L. 
Published: May 2011

ABSTRACTThis paper reports on some of the recent advances in the development and testing of molecular-scale electronic devices, devices that may ultimately be the basis of a molecular-based computer. These advances include: the synthesis of molecules which will perform specific electronic functions, self-assembled monolayer formation of rigid-rod conjugated oligomers, novel methodologies for the design and testing of molecular electronic devices, and the observance of negative differential resistance (NDR) through a molecule.
Influence of Structural Organization On Optical and Transport Properties in Organic Materials
Authors: Cornil J. , Calbert J.Ph. , Beljonne D. , Dos Santos D.A. , Bredas J.L. 
Published: May 2011

ABSTRACTCorrelated quantum-chemical calculations performed on supermolecular structures, i.e., on clusters made of several oligomer chains in interaction, provide insight into structure-property relationships in well-organized molecular films. This supermolecular approach is applied to crystalline phases of two prototypical conjugated oligomers and shows that variations in chain packing can lead to dramatically different optical (Davydov) splittings and carrier mobilities. Optimal chain organizations for various types of devices are discussed.
Nanoscale Control of Layer Thickness for EL Devices by Mass-controlled Layer-by-layer Sequential Adsorption Process
Authors: Shiratori Seimei , Yamada Masayoshi , Ito Takahiro , Wang Tom.C. , Rubner Michael F. 
Published: May 2011

ABSTRACTA mass controlled layer-by-layer sequenitial adsorption process for polyelectlrolytes was newly developed for the fabrication of functional devices using ultra-thin organic film formed by various polymers of different polarity of charge. In this study hydrophobic Ruthenium complex monomer • tris(bipyridyl) ruthenium(II) hexafluorophosphate • was micelle-wrapped with an anionic surfactant, sodium dodecylbenzenesulfonate, and was assembled with PAH (poly (allylamine hydrochloride)), which has the opposite charge, on ITO substrates. With this method, we succeeded in fabricating ultra-thin organic films even when the adsorption material is not polymer but monomer. Moreover it was found that the film thickness of the self-assembled Ru micelle/PAH had a linear relationship with the number of bilayers. By using this process, an EL device was fabricated by depositing the thin film of micelle-wrapping ruthenium complex monomer on ITO and metal electrode on top of the film. Light emission was observed by applying voltage to this device.
Epitaxial Thin Film Structures of Electroluminescent Materials
Authors: Koch Norbert , Hosoi Yoshinobu , Ishii Hisao , Vollmer Antje , Leising Günther , Seki Kazuhiko 
Published: May 2011

ABSTRACTDespite the fast-paced new developments and improvements of applications incorporating conjugated organic materials, rather little effort is made to obtain well-defined structures and thin films of these in order to exploit the highly anisotropic properties (e.g. conductivity, polarized light emission) of most conjugated organic materials. It has been shown that oligomers, which can easily be evaporated under ultrahigh vacuum conditions, exhibit heteroepitaxial growth on various substrates. Depending on the nature of the interaction of the organic molecules with the substrate different orientations can be obtained, as well as by simply changing the conditions of evaporation. Therefore, by going from amorphous or polycrystalline structures to highly textured or single crystalline ones new insights into the physical properties of the materials can be expected, and also new applications. We studied the formation of well-defined films of the electroluminescent oligomer p -sexiphenyl on various metal and semiconductor surfaces and determined the orientation of the molecules by means of low energy electron diffraction (LEED), infrared reflection absorption spectroscopy (IRRAS) and atomic force microscopy (AFM). Depending on the substrate material we found that the molecules are oriented either parallel or perpendicular to the substrate surface. In addition to that, highly oriented 6P films were doped with potassium, and the change in the molecular vibrational signature was investigated with IR-RAS.
Light Emitting Vacuum Evaporated Devices Based on Triaryldiamine Materials and 8-Hydroxyquinoline Complexes of Al(III) and Zn(II)
Authors: Giro Gabriele , Cocchi Massimo , Marco Piergiulio Di , Fattori Valeria , Dembech Pasquale , Fabbri Gaia , Ghedini Mauro 
Published: May 2011

ABSTRACTVapor deposited double-layer (DL) organic light emitting diodes (OLEDs) based on the combination of materials belonging to the triaryldiamine family as hole transporting materials (HTM) and metal complexes of 8-hydroxyquinoline as electron transporting materials (ETM) have been characterized. As HTM N,N'-bis(diphenyl-4-yl)-N,N'-diphenyl-benzidine (NBDB), N,N'-(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB) or N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) were used. As ETM tris-(8-hydroxyquinolinate)-Al(III) (Alq3) or bis-(8-hydroxyquinolinate)-Zn(II) (Znq2) were used. The typical cell configuration was: ITO/HTM/ETM/Ca,Ag. A comparison of the electrical and light emitting features between devices constructed with the new molecule NBDB and NPB or TPD was made, with the aim of improving their efficiency and stability.
Hexa-Alkoxytriphenylenes As Hole Transporting Materials Inc Stable Oleds Using ALQ3 As Emitting Layer
Authors: Emerich Markus , Tasch S. , Resel R. , Leising G. , Freudenmann R. , Hanack M. , Shaheen S. E. , Jabbour G. E. , Peyghambarian N. 
Published: May 2011

ABSTRACTDevices consisting of hexa-alkoxythriphenylene derivatives as hole transport materials and 8-hydroxyquinoline aluminium (Alq3) as emitting layer with ITO as anode and magnesium as cathode are presented. Moreover X-ray diffraction studies of evaporated triphenylene films were performed leading to a better understanding of crystal structure, morphology and the alignment of the triphenylene molecules on the surface of the substrate.
Exciplex Formation in Light Emitting Molecularly Doped Polymer Diodes Based on Polycarbonate:TPD:PBD Blends
Authors: Giro Gabriele , Cocchi Massimo , Marco Piergiulio Di , Fattori Valeria 
Published: May 2011

ABSTRACTObservation of electroluminescence (EL) in single layer of molecularly doped polymer (MDP) films is reported. The EL diodes constructed by spin coating technique contain Bisphenol-A-polycarbonate (PC), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) and 2-(4-biphenyl)-5-(4-terbutylphenyl)1,3,4-oxadiazole (PBD) with the configuration: ITO/PC(20%):TPD(40%):PBD(40%)/Ca, Ag. The EL emission ranges in the green-yellow part of the spectrum and is red shifted respect to the photolu minescence (PL) both of PC:TPD and of PC:PBD. It can be assigned to emission from an exciplex state resulting from the interaction between TPD and PBD, as confirmed by stationary and pulsed fluorescence spectroscopy, and also from other states (triplets, traps or ‘electoplexes’) emitting at lower energies.
Substrate Mediated Ordering in PmPV Thin Films
Authors: McCarthy B. , Czerw R. , Strevens A. , Davey A. P. , Carroll D. L. , Blau W. J. 
Published: May 2011

ABSTRACTMonolayer films of poly(m-phenylenevinylene-co-2,5-dioctoxy-p-phenylenevinylene) (PmPV) supported on highly orientated pyrolytic graphite (HOPG) have been investigated using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). While there are areas of the surface covered with a featureless polymer layer, we also observe large regions with surprisingly long range order. Structural models of the polymer, as well as tunneling spectra, suggest that this ordering is derived from substrate-polymer epitaxy.
Low Voltage Operation of Polymer Light-Emitting Device with Conducting Polymer Distributed Bragg Reflector
Authors: Kawase Takeo , Ho Peter K. H. , Friend Richard H. , Shimoda Tatsuya 
Published: May 2011

ABSTRACTPolymer light-emitting devices with a conducting polymer distributed Bragg reflector (DBR) are reported. Polymer DBRs were formed from alternate spin-coating of poly (3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulphonate) (PSS) as the low-index layer and a hole-transporting polyfluorene derivative as the high-index layer onto ITO deposited glass substrates. The polymer DBR with 5 periods showed reflectivity of 40% at the wavelength of 560nm. Onto this polymer DBR, a green-light-emitting polyfluorene was spin-coated to give the emissive layer and Ca/Al was deposited to form the cathode served another reflector. These LEDs operated successfully at low voltages and emitted light having a narrower spectrum (FWHM=47nm) than structures without the DBR (FWHM=102nm). The peak wavelengths varied corresponding to the thickness of the emissive layer, that is, the cavity length as expected from calculations. The luminance turn-on voltage of the LED with the polymer DBR is 2V, which is the same as LEDs without a DBR. The current was found to be limited by injection in the low field region and limited by space charge density at high fields. The current does not depend on the number of layers in the DBR in the low field region, and this implies that there are no effective energy barriers in the polymer DBR.
Synthesis and Characterization of New Star-Shaped Metal-Containing Polymers for Optical Applications
Authors: Bader Mamoun M. , Pham Phuong-Truc T. , Moser Justin D. 
Published: May 2011

ABSTRACTWe report here on our continued investigations of the synthesis and characterization of new metal-containing polymers incorporating 8-hydroxyquinoline. We reported earlier on three types of linear metal-containing polymers with ether, ester and amide functionalities in the chain's backbone. In this report, we extended our previous studies by targeting star-shaped metal-containing polymers. Again, these polymers still have the favorable structural characteristics, which would allow for a large degree of control over their physio-chemical properties.
Versatile Syntheses of Various Homo- and Copolymers of Poly(1,4-Arylene Vinylene)S
Authors: Martin R. E. , Chuah B. S. , Riehn R. H. , Geneste F. , Cacialli F. , Friend R. H. , Holmes A. B. , Morgado J. 
Published: May 2011

ABSTRACTThe synthesis of poly(1,4-phenylene vinylene)s (PPVs) containing a 2,3-dialkoxy substitution pattern has been developed. Poly[2,3-bis(2-ethylhexyloxy)-1,4-phenylene vinylene)] (BEH-PPV, 4) was prepared and its optical properties compared with the recently discussed poly(2,3-dibutoxy-1,4-phenylene vinylene) (DB-PPV, 1), which showed in contrast to classical 2,5-substituted PPV derivatives a notable blue-shift of the longest-wavelength absorption (λmax) and a considerable increase of the solid-state photoluminescence (PL) efficiency. The two statistical PPV copolymers 5 and 6 comprising 2,3-dibutoxy and dimethyloctylsilyl- or 2,5-bis(dimethyloctylsilyl) side-chains, respectively, were synthesized via the Gilch dehydrohalogenation route. Double-layer light-emitting devices (LEDs) were demonstrated to combine high electroluminescence efficiencies with low turn-on voltages.
Recoverable Photodegradation of Light-Emitting Polymers
Authors: Zhang X. H. , Chua S. J. , Wang H. , Huang W. 
Published: May 2011

ABSTRACTThe photodegradation of light-emitting polymers was studied by measuring the decay of the photoluminescence with exposure time to He-Cd laser beam at room temperature. It was found that the photoluminescence intensity decreases very fast initially, and then tends to saturate on the order of several tens of minutes. More interestingly, it was found that the degradation induced by laser beam can be self-healed. By stopping the exposure of the sample to the laser beam, the photoluminescence intensity recovers gradually without any treatment.
Redox Control of Stilbylvinylpyridine Chormophore Pairwise Orientations: Towards Solid State Materials for Molecular Electronics
Authors: Zahn Steffen , Canary James W. 
Published: May 2011

ABSTRACTTripodal ligand complexes of copper salts are described that display redoxdependent exciton coupled circular dichroism spectra. Significant spectral amplitude is observed at 400 nm in both solution and microcrystalline films. The synthesis and characterization of two new ligands and the preliminary characterization of the circular dichroism properties of their copper complexes is reported. The results constitute a significant step toward the development of molecules that can be used as on/off molecular switches.
Photoinduced Charge Transfer Between Tetracyano-Anthraquino-Dimethane Derivatives and Conjugated Polymers
Authors: Zerza G. , Scharber M. , Segura J. L. , Gomez R. , Martin N. , Sariciftci N. S. 
Published: May 2011

ABSTRACTThe photo-induced charge transfer between tetracyano-anthraquino-dimethane (TCAQ) derivatives and poly(2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene vinylene) MDMO-PPV was studied by means of photoinduced absorption (PIA) spectroscopy in the VIS and IR spectral region and lightinduced electron spin resonance (LESR) spectroscopy. Three different TCAQ derivatives with alkyl-side chains for increased solubility compared to TCAQ and one of them attached to a C60 molecule serve as strong electron acceptors. The photoinduced absorption in the VIS near-IR range shows a broad plateau around 1.8 eV followed by two peaks at 1.35 and 1.24eV for all three acceptors. All PIA features have a power law excitation intensity dependence with an exponent close to 0.5 as expected for bimolecular kinetics. The modulation frequency dependent excited state absorption decreases with a power law. LESR studies of all donor-acceptor combinations show one radical line at a g = 2.0028 with.H = 3.5 Gauss, originating from TCAQ anion and the polymer cation.
Quenching of the Magnetic Field Effect on the Photocurrent and Photocurrent Detected Magnetic Resonance in Conjugated Polymer-Fullerene Diodes
Authors: Scharber M. C. , Brabec C. J. , Padinger F. , Sariciftci N. S. 
Published: May 2011

ABSTRACTWe have studied the effect of a magnetic field on the photocurrent of MDMO-PPV (poly(2-methoxy,5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene) and MDMOPPV/fullerene diodes (plastic solar cells) and performed photocurrent detected magnetic resonance (PCDMR) experiments on these devices consisting of an active layer sandwiched between a low and a high workfunction metal electrode. Results clearly show that the magnetic field effect (MFE) on the photocuttent as well as PCDMR signals are quenched in conjugated polymer/fullerene composite devices in contrast to large signals observed in the pristine conjugated polymer devices. Photoinduced electron transfer from conjugated polymers onto fullerene is proposed to be responsible for this quenching.
Effects of Conformational Diversity and Structural Dynamics on the Optical Properties of Diazoluminomelanin
Authors: Ferris Kim F. , Risser Steven M. , Wagner-Brown Katrina B. , Kiel Johnathan L. , Albanese Richard A. 
Published: May 2011

ABSTRACTDiazoluminomelanin (DALM) is a luminescent polymer belonging to the broader class of conjugated polyphenylene materials, which has shown significant optical activity in response to perturbing fields. In this paper we use semiempirical electronic structure calculations and molecular dynamics simulations to investigate the molecular structure and absorption characteristics of model phenolic oligomers. Molecular dynamics simulations show the polymer backbone can be extremely flexible depending upon the ionization state of the phenolic hydroxyl groups. The interring torsion angle is a critical variable as it relates charge localization effects and electronic excitation energies. Comparison with experimental data demonstrates the need for a multistate basis to describe the absorption properties of this system.
Efficient Electroluminescence from Type I Quantum Confined Structure Utilizing Organic Dye Materials
Authors: Ohmori Yutaka , Sawatani Takumi , Ando Kazumichi , Yosino Katsumi 
Published: May 2011

ABSTRACTImprovement of electroluminescence (EL) efficiency by utilizing quantum confined structure, so-called type I superlattice, has been discussed. Superlattice structures, which consist of 8-hydroxyquinoline aluminum (Alq3) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), and of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) and Alq3, and of (1,10-phenanthroline)-tris -(4,4,4-trifluoro -1-(2-thienyl)-butane-1,3-dionate) europium (III) (Eu(TTA )3phen) and (N,N'-disalicylidene-1,6-hexanediaminate) zinc (II) (1AZM -Hex) are studied. As a result, strong EL emission is observed in the type I superlattice structures. The mechanism of enhancement is discussed using energy band structure.