bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, self‐assembly, and thermosensitive properties of ethyl cellulose‐g‐P(PEGMA) amphiphilic copolymers
Authors: Li Yanxiang , Liu Ruigang , Liu Wenyong , Kang Hongliang , Wu Min , Huang Yong 
Published: September 2008

AbstractEthyl cellulose graft poly(poly(ethylene glycol) methyl ether methacrylate) (EC‐g‐P(PEGMA)) amphiphilic copolymers were synthesized via atom transfer radical polymerization (ATRP) and characterized by FTIR, 1H NMR, and gel permeation chromatography. Reaction kinetics analysis indicated that the graft copolymerization is living and controllable. The self‐assembly and thermosensitive property of the obtained EC‐g‐P(PEGMA) amphiphilic copolymers in water were investigated by dynamic light scattering, transmission electron microscopy, and transmittance. It was found that the EC‐g‐P(PEGMA) amphiphilic copolymers can self‐assemble into spherical micelles in water. The size of the micelles increases with the increase of the side chain length. The spherical micelles show thermosensitive properties with a lower critical solution temperature around 65 °C, which almost independent on the graft density and the length of the side chains. The obtained EC‐g‐P(PEGMA) graft copolymers have both the unique properties of poly(ethylene glycol) and cellulose, which may have the potential applications in biomedicine and biotechnology. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 46: 6907–6915, 2008
Health‐related fitness and trainability in children with cystic fibrosis
Authors: Gruber W. , Orenstein D.M. , Braumann K.M. , Hüls G. 
Published: September 2008

AbstractThe objective of this study was to examine the effects of a supervised exercise training program performed during an in patient rehabilitation course on various attributes of health‐related fitness, e.g., flexibility, balance and coordination. 286 patients with CF, age range 6–18 years (11.8 ± 3.4 years), mean forced expiratory volume in 1 sec (FEV1 82.7 ± 22.3% predicted) were included. Patients performed the modified Munich fitness test (mMFT) to assess flexibility, balance, strength and coordination. To assess aerobic capacity a 6‐min walk‐test (6MWT) was performed. In addition, some of the patients performed an incremental exercise test on a bicycle ergometer using the Godfrey protocol before and after the exercise training program. The supervised training program consisted of 4–6 weeks of different sports activities 5 times per week. After training, pulmonary function showed a significant (P < 0.05) increase. All test items of the mMFT improved significantly (P < 0.05). Compared to healthy children test scores achieved from children with CF in the mMFT were lower but within a normal range. Our children with CF had a lower walk distance in 6MWT (P < 0.05) compared to healthy. Our findings clearly demonstrated benefits of a systematic exercise training program on components of physical fitness in patients with CF, with improvements of test‐tasks to predicted normal in some cases. The results from our study suggested that an exercise training program in CF should be focused on several aspects of physical fitness including all components of physical fitness, e.g. aerobic endurance, flexibility, balance and motor skills. Pediatr Pulmonol. 2008; 43:953–964. © 2008 Wiley‐Liss, Inc.
Exhaled leukotriene B4 in children with community acquired pneumonia
Authors: Carraro Silvia , Andreola Barbara , Alinovi Rossella , Corradi Massimo , Freo Luisa , Da Dalt Liviana , Baraldi Eugenio 
Published: September 2008

AbstractBackgroundThe infiltrate in pneumonia is characterized by a large number of activated neutrophils, for which leukotriene B4 (LTB4) is a strong chemotactic agent. Exhaled breath condensate (EBC) is a non‐invasive technique for studying the lower airways. The present study was conducted to measure EBC LTB4 as a potential non‐invasive marker of inflammatory response in community acquired pneumonia (CAP).MethodsEighteen children with CAP and 17 healthy children were recruited (age 5–13). The CAP children underwent physical examination, chest X‐ray, leukocyte count and C‐reactive protein measurement. The CAP and the control children performed spirometry, exhaled nitric oxide measurement (FENO) and EBC collection for LTB4 assessment. In the CAP children spirometry, FENO and EBC collection were repeated twice over a 1‐month follow‐up.ResultsLTB4 EBC concentrations were higher in children with CAP than in healthy controls (10 pg/ml [7.0–15.3] vs. 3 pg/ml [3.0–6.9], P = 0.001) and decreased after 1 week (3 pg/ml [3.0–7.2], P < 0.01) with no further change a month later. In the acute phase spirometry demonstrated a restrictive pattern that gradually improved later. No difference in FENO levels was found between children with CAP and healthy controls.ConclusionExhaled LTB4 levels increase in CAP and return to normal after 1 week. EBC collection is feasible in children with CAP and may represent a new way to non‐invasively monitor the lung's biological response to infections. Pediatr Pulmonol. 2008; 43:982–986. © 2008 Wiley‐Liss, Inc.
Structural and Preliminary Explosive Property Characterizations of New 3,4,5‐Triamino‐1,2,4‐triazolium (Guanazinium) Salts
Authors: Darwich Chaza , Klapötke Thomas M. , Sabaté Carles Miró 
Published: September 2008

AbstractTwo new highly stable energetic salts were synthesized in reasonable yield by using the high nitrogen‐content heterocycle 3,4,5‐triamino‐1,2,4‐triazole and resulting in its picrate and azotetrazolate salts. 3,4,5‐Triamino‐1,2,4‐triazolium picrate (1) and bis(3,4,5‐triamino‐1,2,4‐triazolium) 5,5′‐azotetrazolate (2) were characterized analytically and spectroscopically. X‐ray diffraction studies revealed that protonation takes place on the nitrogen N1 (crystallographically labelled as N2). The sensitivity of the compounds to shock and friction was also determined by standard BAM tests revealing a low sensitivity for both. B3LYP/6–31G(d, p) density functional (DFT) calculations were carried out to determine the enthalpy of combustion (ΔcH(1)=−3737.8 kJ mol−1, ΔcH(2)=−4577.8 kJ mol−1) and the standard enthalpy of formation (ΔfH°(1)=−498.3 kJ mol−1, (ΔfH°(2)=+524.2 kJ mol−1). The detonation pressures (P(1)=189×108 Pa, P(2)=199×108 Pa) and detonation velocities (D(1)=7015 m s−1, D(2)=7683 m s−1) were calculated using the program EXPLO5.
Thermal Analysis Studies on the Slow‐Propagation Tungsten Type Delay Composition System
Authors: Lu Kai‐Tai , Yang Ching‐Chyuan 
Published: September 2008

AbstractThermal analysis techniques were applied to investigate the reaction characteristics of a slow‐propagation tungsten type delay composition system by means of differential scanning calorimetry (DSC) and thermogravimetry (TG). The ingredients of the delay composition were tungsten, barium chromate, potassium perchlorate, diatomaceous earth, and Viton. A formula of delay composition with a weight percentage of W/BaCrO4/KClO4/D. E./Viton=27 : 54 : 11 : 6 : 2 has been used in a self‐destruction mechanism of fuse, which was set as the original formula. In the first place, the reaction heat and weight loss for different compositions without Viton were measured during the reaction. The influence of each ingredient of the formula on the reaction system was analyzed from these experimental results. Afterward Viton was added in the samples of experiment to measure and analyze the influence of Viton on the reaction system. Finally, 28 experimental formulas of delay composition were designed on the condition that the weight percentage of Viton was kept constant and the maximum variation of weight percentage of all the others was limited within 20%. The delay compositions of various formulas were granulated and then the variations of reaction characteristics were measured to analyze the influence of weight variation of each ingredient on reaction characteristics. The results of this study are very important and useful for improving the self‐destruction mechanism of fuse.
Very short peptides with stable folds: Building on the interrelationship of Trp/Trp, Trp/cation, and Trp/backbone–amide interaction geometries
Authors: Eidenschink Lisa , Kier Brandon L. , Huggins Kelly N. L. , Andersen Niels H. 
Published: September 2008

AbstractBy combining a favorable turn sequence with a turn flanking Trp/Trp interaction and a C‐terminal H‐bonding interaction between a backbone amide and an i‐2 Trp ring, a particularly stable (ΔGU > 7 kJ/mol) truncated hairpin, Ac‐WI‐(D‐Pro‐D‐Asn)‐KWTG‐NH2, results. In this construct and others with a W‐(4‐residue turn)‐W motif in severely truncated hairpins, the C‐terminal Trp is the edge residue in a well‐defined face‐to‐edge (FtE) aryl/aryl interaction. Longer hairpins and those with six‐residue turns retain the reversed “edge‐to‐face” (EtF) Trp/Trp geometry first observed for the trpzip peptides. Mutational studies suggest that the W‐(4‐residue turn)‐W interaction provides at least 3 kJ/mol of stabilization in excess of that due to the greater β‐propensity of Trp. The π–cation, and Trp/Gly‐HN interactions have been defined. The latter can give rise to >3 ppm upfield shifts for the Gly‐HN in ‐WXnG‐ units both in turns (n = 2) and at the C‐termini (n = 1) of hairpins. Terminal YTG units result in somewhat smaller shifts (extrapolated to 2 ppm for 100% folding). In peptides with both the EtF and FtE W/W interaction geometries, Trp to Tyr mutations indicate that Trp is the preferred “face” residue in aryl/aryl pairings, presumably because of its greater π basicity. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Oxidative folding of synthetic polypeptides S‐protected as tert‐butylthio derivatives
Authors: Verdini Antonio , Terenzi Silvia , Brossard Vincent , Roggero Mario , Corradin Giampietro 
Published: September 2008

AbstractA new method for oxidative folding of synthetic polypeptides assembled by stepwise solid phase synthesis is introduced. Folding is obtained in excellent yields by reacting S‐tert‐butylthiolated polypeptides with a 100‐fold molar excess of cysteine at 37 °C in a slightly alkaline buffer containing chaotropic salts, and in the presence of air‐oxygen. This novel protocol has been applied to the folding of S‐tert‐butylthiolated human thymus and activation‐regulated chemokine (hu‐TARC) derivatives as well as to larger segments of Plasmodium falciparum and Plasmodium berghei circumsporozoite proteins. Folded P. falciparum polypeptides have been used as substrates of endoproteinase Glu‐C (Glu‐C) and endoproteinase Asp‐N (Asp‐N) in an attempt to identify their disulfide connectivities. Particular practical advantages of the present method are (i) easy purification and storage of the S‐protected peptide derivatives, (ii) elimination of the risk of cysteine alkylation during the acidolytic cleavage deprotection and resin cleavage steps, (iii) possibility to precisely evaluate the extent of folding and disulfide bond formation by mass spectrometry, and (iv) facile recovery of the final folded product. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Liquid phase deposition of iron and cobalt doped TiO2 epitaxial thin films
Authors: Chan K. Y. S. , Goh G. K. L. , Han M. Y. 
Published: September 2008

AbstractLiquid phase deposition (LPD) is a wet process in which metal oxide thin films can be deposited on substrates via a chemical equilibrium reaction between a metal fluoro‐complex and a metal oxide in aqueous solution. In this study, iron and cobalt doped TiO2 anatase thin films were deposited on (001) oriented SrTiO3 single crystal substrates using liquid phase deposition. The process involves the reaction of ammonium hexafluorotitanate and boric acid, in the presence of FeOOH–HF and Co(NO3)2–ethylenediamine (en) for the iron and cobalt doped TiO2 films respectively. Cobalt doping was also attempted by immersing a non‐doped TiO2 film in a solution of Co‐en ions. XRD shows that the films are c‐axis oriented and films epitaxy was confirmed using pole figure measurements. No metallic secondary phases were detected by XRD and XPS. The iron and cobalt doped films are observed to yield room temperature ferromagnetism. The insulating nature of the films suggests that bound magnetic polarons are responsible for the observed ferromagnetism. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical spray deposition of zinc oxide nanostructured layers from zinc acetate solutions
Authors: Dedova T. , Klauson J. , Badre C. , Pauporté Th. , Nisumaa R. , Mere A. , Volobujeva O. , Krunks M. 
Published: September 2008

AbstractZinc oxide (ZnO) films were deposited by chemical spray from zinc acetate aqueous solutions using continuous and pulsed spray modes. ZnO films were characterized by scanning electron microscopy, atomic force microscopy, optical transmittance, and water contact angle (CA) measurements. ZnO films with highly structured surfaces comprising nanoneedles or nanorods with root mean square roughness (Sq) up to 60 nm were grown using the continuous spray mode. Doping with In or using pulsed spray mode leads to smoother ZnO surfaces with Sq of 20 nm. The optical transmittance of the film is controlled by its surface morphology and internal scattering. Water contact angle measurements reveal that as‐sprayed ZnO films with nanoneedle or nanorod‐like crystals on the surface are hydrophilic with CA ∼10°. Structured surfaces become hydrophobic with CA ∼134° after treatment with stearic acid. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrochemical growth of ZnO nanowires inside nanoporous alumina templates. A comparison with metallic Zn nanowires growth
Authors: Ramirez Daniel , Pauporte Thierry , Gomez Humberto , Lincot Daniel 
Published: September 2008

AbstractMolecular oxygen reduction in presence of Zn(II) allowed to get arrays of zinc oxide (ZnO) nanowires (NWs) inside thick anodic alumina membranes (AAM), previously made by anodization in oxalic acid. A Zinc (Zn) NWs array made by electrochemical deposition (ED) was employed as a metal reference in order to compare its growth behavior with respect to that of ZnO, a semiconducting material. Chronoamperometric measurements for Zn NWs showed a typical response for metallic growth inside porous templates while ZnO NWs did not show this behavior. We observed that Zn NWs grew faster than ZnO NWs as checked by the electrical charge. SEM images showed the presence of ZnO NWs only after long deposition time. X‐ray diffraction data confirmed the ZnO structure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The characterizations of superconducting MoC/Mo2C nanocomposites embedded in a magnetic graphite matrix
Authors: Wang Z. H. , Li D. , Geng D. Y. , Ma S. , Liu W. , Zhang Z. D. 
Published: September 2008

AbstractA three‐dimensional molybdenum‐carbides/graphite network formed by superconducting MoC/Mo2C nanograins embedded in a magnetic graphite matrix was fabricated. The temperature dependence of magnetization of the MoC/Mo2C nanocomposites indicates that the superconducting transition temperatures (TC) of Mo2C and MoC nanocrystals are 8 K and 11.5 K, respectively. These transition temperatures are lower than those of their corresponding bulk counterparts, due to the detrimental influence of magnetic graphite. The magnetization influenced by edge barrier and magnetic graphite are investigated for the MoC/Mo2C nancomposites embedded in the magnetic graphite matrix. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of solution‐processed pentacene thin film transistors
Authors: Natsume Yutaka 
Published: September 2008

AbstractThe electrical and chemical stability of solution‐processed pentacene thin film transistors (TFTs) was investigated using analytical models reported by Horowitz et al. in comparison with vacuum‐deposited TFTs. The estimated total trap density of the solution‐processed film was one to two order(s) of magnitude lower than that of the vacuum‐deposited film. The low trap density of the solution‐processed film is due to large crystalline domains, which include only a few structural defects, in contrast to the vacuum‐deposited film. The solution‐processed film is also superior to the vacuum‐deposited film in electrical stability during long‐term storage in air. That is, a considerable shift of the transistor characteristics in the subthreshold region including a threshold voltage was observed, especially in the case of the vacuum‐deposited TFT. The change in the electrical properties is attributed to the increase of oxidation‐induced chemical impurities, which were confirmed by surface mass spectroscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthetic transverse thermoelements made from porous bismuth telluride and single crystal bismuth
Authors: Goldsmid H. J. 
Published: September 2008

AbstractSynthetic transverse thermoelements may be produced from materials that have layered structures with two components. It is desirable that the electrical and thermal conductivities should be much greater for one component than for the other. It is also necessary that the longitudinal figure of merit for a conventional couple made from the two components should be high. Here we show that a transverse thermoelement made from single‐crystal bismuth and polycrystalline bismuth‐antimony telluride largely meets these requirements when the latter material is porous. If the porosity is such that the conductivities have about 20% of their values for the fully dense alloy, the dimensionless transverse figure of merit is over 0.6. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐frequency permeability of sputtered Fe–Co–B‐based soft magnetic thin films
Authors: Liao Jiansheng , Feng Zekun , Qiu Jing , Tong Yanqun 
Published: September 2008

AbstractHigh‐frequency characteristics of a series of soft magnetic Fe–Co–B‐based thin films are investigated in the range of 0.5–5 GHz. It is found that in‐plane anisotropy can be caused by oblique incidence or applying an external field during deposition. The permeability and the resonance frequency are basically consistent with Snoek's law. Ni can improve the magnetic properties greatly except for the decrease of resistivity. In order to reduce the dissipation and increase the resistivity, SiO2is added to the film. Excellent high‐frequency permeability of (Fe40Co40B20)0.619Ni12.642–(SiO2)25.416is obtained: the resonance frequency exceeds 2.2 GHz; the real and the imaginary parts of the permeability at 0.5 GHz are 476 and 92, respectively; the resistivity of the film reaches 682 μΩ cm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon nanowire optical Raman line shapes at cryogenic and elevated temperatures
Authors: Scheel H. , Khachadorian S. , Cantoro M. , Colli A. , Ferrari A. C. , Thomsen C. 
Published: September 2008

AbstractWe report the Raman spectra of silicon nanowires (SiNWs) in a wide temperature range, between 2 K and 850 K. At room temperature we find a strong influence on the spectrum from applied laser excitation powers. These effects can be attributed a laser heated sample, leading to an inhomogeneous temperature distribution within the laser‐spot. If the laser excitation power is small (below 100 μW) such effects are negligible, and we find a temperature dependence governed by threephonon decay processes. The results from temperature dependent measurements indicate a change of sample morphology due to heating. Raman measurements on SiNWs immersed in superfluid helium at ≈ 2 K show very strong red‐shifts, even though they still have the perfect thermal contact via the superfluid helium. Considering anharmonic effects we find massively increased Si core temperatures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular and electronic structure of PTCDA on bilayer graphene on SiC(0001) studied with scanning tunneling microscopy
Authors: Lauffer Peter , Emtsev Konstantin V. , Graupner Ralf , Seyller Thomas , Ley Lothar 
Published: September 2008

AbstractEpitaxial growth of graphene on SiC surfaces by solid state graphitization is a promising route for future development of graphene based electronics. In the present work we study the morphology and molecular scale structure of monolayer films of 3,4,9,10‐perylene tetracarboxylic dianhydrid (PTCDA) on bilayer graphene on SiC(0001) by scanning tunneling microscopy (STM). First we discuss how the PTCDA molecules adsorb on bilayer graphene. We specially regard the density of PTCDA molecules at monolayer coverage. From the comparison with experiments on HOPG (Au(111) and Ag(110) from literature) we infer a non‐planar adsorption geometry of PTCDA molecules on bilayer graphene. The electronic structure of the surrounding bilayer graphene substrate is investigated via scanning tunneling spectroscopy (STS) and reveals n‐type doping of bilayer graphene during adsorption of PTCDA. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of metallic and semiconducting single‐wall carbon nanotubes
Authors: Miyata Yasumitsu , Yanagi Kazuhiro , Maniwa Yutaka , Kataura Hiromichi 
Published: September 2008

AbstractOptical properties of high purity metallic and semiconducting single‐wall carbon nanotubes (SWCNTs) were investigated from far infrared to ultraviolet by optical absorption spectroscopy. It was found that the metallic SWCNT thin film has larger infrared absorption intensity than the semiconducting one. Furthermore, little changes in the optical absorption spectrum and the DC sheet resistance against molecular physisorptions were revealed in the metallic SWCNTs thin film. The stability of the metallic SWCNTs results from their constant electronic density of state near the Fermi level. On the other hand, the existence of semiconducting SWCNTs in the films makes their infrared absorption intensity and the sheet resistance more sensitive to the adsorption of molecules mainly due to carrier doping. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
G– and G+ in the Raman spectrum of isolated nanotube: a study on resonance conditions and lineshape
Authors: Telg H. , Fouquet M. , Maultzsch J. , Wu Y. , Chandra B. , Hone J. , Heinz T. F. , Thomsen C. 
Published: September 2008

AbstractWe analyze the high‐energy Raman modes, G+ and G–, in a pair of one metallic and one semiconducting nanotube grown across a 100 mm wide slit. By combining Raman resonance profiles of the radial breathing mode and the high‐energy modes, we assign the broad G– peak to a metallic and the G+ peak to a semiconducting nanotube. Considering theoretical predictions we show that both peaks, G– and G+, originate from the LO phonon. The G– peak is the longitudinal mode of the metallic tube; it is broadened and downshifted due to strong electron‐phonon coupling in the metallic nanotube. The G+ peak is due to the longitudinal mode in the semiconducting tube. An asymmetric lineshape of the G– peak agrees with observations of the asymmetry to be an intrinsic feature of metallic nanotubes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and electronic properties of potassium doped graphite single crystals
Authors: Grüneis A. , Attaccalite C. , Rubio A. , Molodtsov S. L. , Vyalikh D. V. , Fink J. , Follath R. , Pichler T. 
Published: September 2008

AbstractHere we revisited the electronic structure of potassium doped graphite using angle‐resolved photoemission spectroscopy (ARPES). We perform an analysis of the charge transfer from potassium to graphite employing a tight‐binding model for the band structure. Our ARPES measurements clearly show that the π* band of graphite becomes occupied upon deposition and intercalation of small amounts of potassium.The observed shift in the Fermi level of ∼ 400 meV is well below the appearance of staged graphite compounds and is described by a rigid band shift model. The π* band in pristine graphite is unoccupied and can therefore not be measured by ARPES. Thus potassium doping in the dilute limit provides a key for measuring the π* bands close to the Fermi level by ARPES. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)