bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteome profiling reveals potential toxicity and detoxification pathways following exposure of BEAS‐2B cells to engineered nanoparticle titanium dioxide
Authors: Ge Yue , Bruno Maribel , Wallace Kathleen , Winnik Witold , Prasad Raju Y. 
Published: March 2011

AbstractOxidative stress is known to play important roles in engineered nanomaterial‐induced cellular toxicity. However, the proteins and signaling pathways associated with the engineered nanomaterial‐mediated oxidative stress and toxicity are largely unknown. To identify these toxicity pathways and networks that are associated with exposure to engineered nanomaterials, an integrated proteomic study was conducted using human bronchial epithelial cells, BEAS‐2B and nanoscale titanium dioxide. Utilizing 2‐DE and MS, we identified 46 proteins that were altered at protein expression levels. The protein changes detected by 2‐DE/MS were verified by functional protein assays. These identified proteins include some key proteins involved in cellular stress response, metabolism, adhesion, cytoskeletal dynamics, cell growth, cell death, and cell signaling. The differentially expressed proteins were mapped using Ingenuity Pathway Analyses™ canonical pathways and Ingenuity Pathway Analyses tox lists to create protein‐interacting networks and proteomic pathways. Twenty protein canonical pathways and tox lists were generated, and these pathways were compared to signaling pathways generated from genomic analyses of BEAS‐2B cells treated with titanium dioxide. There was a significant overlap in the specific pathways and lists generated from the proteomic and the genomic data. In addition, we also analyzed the phosphorylation profiles of protein kinases in titanium dioxide‐treated BEAS‐2B cells for a better understanding of upstream signaling pathways in response to the titanium dioxide treatment and the induced oxidative stress. In summary, the present study provides the first protein‐interacting network maps and novel insights into the biological responses and potential toxicity and detoxification pathways of titanium dioxide.
Small colony variants of Staphylococcus aureus reveal distinct protein profiles
Authors: Kriegeskorte André , König Simone , Sander Gunnar , Pirkl Alexander , Mahabir Esther , Proctor Richard A. , von Eiff Christof , Peters Georg , Becker Karsten 
Published: March 2011

AbstractSmall‐colony variants (SCVs) of Staphylococcus aureus represent a slow‐growing subpopulation causing chronic and relapsing infections due to their physiological adaptation on an intracellular lifestyle. In this first proteomic study on physiological changes associated with a natural, clinically derived SCV, its proteomic profile was investigated in comparison to corresponding isogenic strains displaying normal (clinical wild‐type strain, complemented hemB mutant and spontaneous revertant of the clinical SCV) and SCV phenotypes (hemB mutant and gentamicin‐induced SCV). Applying an ultra‐high resolution chromatography and high mass accuracy MSE‐based label‐free relative and absolute protein quantification approach, the whole cytoplasmic proteome of this strain sextet was investigated in a growth phase‐controlled manner covering early‐exponential, late‐exponential and stationary phases. Of 1019 cytoplasmic proteins identified, 154 were found to be differently regulated between strains. All SCV phenotypes showed down‐regulation of the tricarboxylic acid (TCA) cycle‐related proteins and of a protein cluster involved in purine/pyrimidine and folate metabolism. In contrast to hemB mutant and gentamicin‐induced SCVs, the clinically derived SCVs showed no prominent up‐regulation of glycolytic proteins. The spontaneous switch into the normal phenotype resulted in up‐regulation of TCA cycle‐related parts, while oxidative stress‐related proteins were down‐regulated. However, the natural revertant from the clinical SCV retained also dominant protein features of the clinical SCV phenotype. In conclusion, physiological changes between normal and SCV S. aureus phenotypes are more complex than reflected by defined electron transport chain‐interrupting mutants and their complemented counterparts.
Synthesis of novel hyperbranched polymer through cationic ring‐opening multibranching polymerization of 2‐hydroxymethyloxetane
Authors: Satoh Toshifumi , Tamaki Masaki , Taguchi Tsukasa , Misaka Hideki , Hoai Nguyen To , Sakai Ryosuke , Kakuchi Toyoji 
Published: March 2011

AbstractThe cationic ring‐opening multibranching polymerization of 2‐hydroxymethyloxetane (1) as a novel latent AB2‐type monomer was carried out using trifluoromethane sulfonic acid or trifluoroboron diethyl etherate by a slow‐monomer‐addition (SMA) method. The polymer yield of poly‐1 ranged from ca. 58–88%, which increase with the increasing monomer addition time on the SMA method. The absolute molecular weights (Mw,MALLS) and the polydispersities of poly‐1 were in the range of 8,000–43,500 and 1.45–4.53, respectively, which also increased with the increasing monomer addition time. The Mark‐Houwink‐Sakurada exponents α in 0.2 M NaNO3 aq. were determined to be 0.02–0.25 for poly‐1, indicating that poly‐1 has compact forms in the solution because of the highly branched structure. The degree of the branching value of poly‐1, which was calculated by Frey's equation, ranged from ca. 0.50 to 0.58, which increased with the increasing monomer addition time. The steady shear flow of poly‐1 in aqueous solution exhibited a Newtonian behavior with steady shear viscosities independent of the shear rate. The results of the MALLS, NMR, and viscosity measurements indicated that poly‐1 is composed of a highly branched structure, i.e., the hyperbranched poly (2‐hydroxymethyloxetane). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
A versatile single‐electron‐transfer mediated living radical polymerization route to galactoglucomannan graft‐copolymers with tunable hydrophilicity
Authors: Voepel Jens , Edlund Ulrica , Albertsson Ann‐Christine 
Published: March 2011

AbstractCu(0) mediated living radical polymerization was successfully applied to synthesize graft‐copolymers from the hemicellulose acetylated galactoglucomannan. Functionalizing the polysaccharide backbone with α‐bromo isobutyric acid gave rise to a macroinitiator for single‐electron‐transfer mediated living radical polymerization (SET‐LRP). This macroinitiator with a degree of substitution of 0.15 or 0.20 was used in the graft‐SET‐LRP of methyl methacrylate in dimethyl sulfoxide as well as N‐isopropyl acrylamide and acrylamide in water. Kinetic analyses confirm conversions of up to 73% and a controlled behavior of the SET‐LRP process providing high molecular weight hemicellulose‐based hybrid copolymers with a brush‐like architecture. Derived graft‐copolymers varied significantly in solubility properties, ranging from hydrophobic via temperature responsive water‐solubility to water‐soluble. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Effect of night symptoms and disease severity on subjective sleep quality in children with non‐cystic‐fibrosis bronchiectasis
Authors: Erdem Ela , Ersu Refika , Karadag Bulent , Karakoc Fazilet , Gokdemir Yasemin , Ay Pinar , Akpinar Ihsan Nuri , Dagli Elif 
Published: April 2011

AbstractBackgroundNight‐time symptoms and hypoxemia during sleep may affect sleep quality in children with chronic lung disease such as bronchiectasis. Poor sleep quality may impair growth, learning, and emotional development of children. Our aim was to assess the sleep quality and associated factors in children with non‐cystic fibrosis bronchiectasis.MethodsFifty‐four patients with bronchiectasis and age‐matched controls were included to the study. Pittsburgh Sleep Quality Index (PSQI) and Pediatric Sleep Questionnaire (PSQ) were used to evaluate sleep quality and presence of sleep disordered breathing. A global sum of 5 or more according to PSQI indicated a poor sleep quality. A cut‐off value of 0.33 in PSQ was used to identify pediatric sleep disordered breathing. Association between PSQI, pulmonary function tests, symptoms and HRCT scores were evaluated.ResultsThirty‐seven percent of patients with bronchiectasis and 17% of patients in the control group had poor sleep quality (P < 0.05). Patients with sputum and wheezing had poorer sleep scores (P = 0.003 and P = 0.005). The association of wheezing and breathlessness during night time with sleep quality tended to be significant (P = 0.05). Twenty‐two percent of patients with bronchiectasis and 9% of controls had sleep disordered breathing (P = 0.003). Bronchiectasis patients who snored had poorer sleep quality (P < 0.001) and patients with wheezing had significantly higher rate of snoring (P = 0.04). Children with worse HRCT scores also had worse sleep quality (r = 0.28, P = 0.04).ConclusionsPatients with bronchiectasis have disturbed sleep associated with severity of disease. Night symptoms increase the risk of poor sleep quality. Sleep disordered breathing and sleep quality should be assessed in these patients. Pediatr. Pulmonol. 2011; 46:919–926. © 2011 Wiley‐Liss, Inc.
Urine proteomics in kidney and urogenital diseases: Moving towards clinical applications
Authors: Zürbig Petra , Dihazi Hassan , Metzger Jochen , Thongboonkerd Visith , Vlahou Antonia 
Published: March 2011

AbstractTo date, multiple biomarker discovery studies in urine have been conducted. Nevertheless, the rate of progression of these biomarkers to qualification and even more clinical application is extremely low. The scope of this article is to provide an overview of main clinically relevant proteomic findings from urine focusing on kidney diseases, bladder and prostate cancers. In addition, approaches for promoting the use of urine in clinical proteomics including potential means to facilitate the validation of existing promising findings (biomarker candidates identified from previous studies) and to increase the chances for success for the identification of new biomarkers are discussed.
Infrared spectroscopic growth studies of an organic semiconductor
Authors: Glaser Tobias , Binder Martin , Lennartz Christian , Schildknecht Christian , Pucci Annemarie 
Published: March 2011

AbstractWe show an example for sensitive in situ monitoring of organic film growth by means of infrared spectroscopy. The phosphorescent emitter material used in this study was developed for the application in organic light emitting diodes. During thermal evaporation under ultra‐high vacuum conditions its vibrational spectrum is monitored and compared to spectra of pristine powder and calculated ones. This comparison proves that the molecules were not destroyed during evaporation and that their mutual interaction in the condensed layer gives rise to only marginal spectral modifications, which indicates the formation of a van der Waals‐like solid where the molecular electronic properties are preserved. The development of infrared spectral features with film thickness made obvious that no phase changes occurred during deposition from beginning on up to several ten nanometers thickness. Spectroscopy under different polarization conditions reveals that isotropic layers have formed, which is supported by the special molecular properties of the material under investigation.
Effect of postdeposition annealing on electrical properties of RF‐magnetron sputtered CeOx gate on 4H‐silicon carbide
Authors: Chuah SooKiet , Cheong KuanYew , Lockman Zainovia , Hassan Zainuriah 
Published: March 2011

AbstractThis research investigated the electrical characteristics of CeOx thin films deposited on n‐type 4H‐SiC via RF‐magnetron sputtering technique. Postdeposition annealing of CeOx was performed at different annealing temperatures (400, 600, 800, and 1000 °C) for 30 min in an argon ambient. The thickness of the deposited CeOx ranging from 30 to 40 nm was measured by an ellipsometer. All annealed samples showed smooth surface morphology without any physical defects. In this work, the lowest root‐mean square surface roughness was detected at samples annealed at 1000 °C. Prior to electrical characterization, all annealed samples demonstrated a positive flat‐band voltage shift indicating that negative effective oxide charge was present in the oxide layer. The sample annealed at 1000 °C revealed the lowest effective oxide charge and interface trap density as compared with other samples. The calculated interface trap density and effective oxide charge from high‐frequency capacitance–voltage curve were correlated with leakage current density and electric breakdown field. The Fowler–Nordheim tunneling mechanism only occurred in the sample annealed at 1000 °C. The leakage current density and electric breakdown field were enhanced as the postdeposition annealing increased to 1000 °C as compared with other samples.
High pressure semiconductor physics: Looking toward the future on the shoulder of the past
Authors: Yu Peter Y. 
Published: March 2011

AbstractHigh pressure measurements attracted attention from the Semiconductor Physics community after the discovery of William Paul's Empirical Rule. The technique gained further momentum with the invention of the diamond‐anvils high pressure cell. Since diamond is transparent from near IR to near UV many forms of optical spectroscopy (such as photoluminescence, modulation spectroscopy, and Raman scattering) have now been routinely carried out under high pressure. The fact that diamonds are also transparent to X‐ray means structural phase transitions induced by pressure can be studied together with optical measurements. Further advances, such as electrical and magnetic measurements under hydrostatic (and sometimes quasi‐hydrostatic) high pressure conditions, have established high pressure as a general, powerful, and indispensable technique in studying semiconductors. From a review of these past achievements I will attempt to “predict” how high pressure techniques will impact semiconductor physics in the future. I will draw examples from areas as diverse as new materials for spintronics and renewable energies, topological insulators to possible multi‐ferroic semiconductors.
Comparative study of GaAs and GaInNAs/GaAs multi‐quantum well solar cells
Authors: Royall B. , Balkan N. , Mazzucato S. , Khalil H. , Hugues M. , Roberts J. S. 
Published: March 2011

AbstractCurrent–voltage (I–V) characteristics together with spectral quantum efficiency (QE) measurements are performed on a GaAs control and GaInNAs/GaAs multi‐quantum well (MQW) solar cell under illumination with the AM1.5G spectrum. Nitrogen and Indium composition in the GaInNAs wells were selected as to ensure lattice matching to GaAs. The wells are shown to extend the spectral response to longer wavelengths but also cause a reduction in the QE at wavelengths below the GaAs band gap. Furthermore, the addition of wells generally causes a large decrease in open circuit voltage due to the increased dark current. The MQW cell reaches an efficiency of 5% compared to 8.5% for the GaAs control cell.
Pressure effects on the charge carrier transportation of polycrystalline LiCr0.35Mn0.65O2
Authors: Hu Tingjing , Cui Xiaoyan , Yang Jie , Han Yonghao , Liu Hongwu , Gao Chunxiao , Du Fei , Chen Gang 
Published: March 2011

AbstractLiCr0.35Mn0.65O2 powders were investigated by using in situ impedance spectroscopy under high pressure. The impedance spectroscopy of the Nyquist representation showed two overlapped arcs in the complex impedance plane which corresponded to the electrical transportation of grain and grain boundary respectively. By using the representation of Z ″/f versus Z ′, the resistance and the relaxation frequency of grain and grain boundary were obtained under different pressures. It was found that at every phase transition region, both the resistance and the relaxation frequency of grain and grain boundary changed discontinuously. Pressure decreases the effective scattering section of grain and grain boundary to the charge carriers obviously and makes their transport easier. The variation of defects in the grain boundary region leads the sample resistance in the decompression process is much lower than that in the compression process. This indicates the pressure treatment has a positive contribution to the electrochemical performance of LiCr0.35Mn0.65O2. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High pressure impedance spectroscopy of CdS nanocrystals
Authors: Ren Wanbin , Han Yonghao , Liu Cailong , Wang Yue , Liu Bao , Hu Tingjing , Cui Xiaoyan , Gao Chunxiao 
Published: March 2011

AbstractImpedance spectroscopy of CdS nanocrystals (100 nm in diameter on average) was studied with the applied pressure up to 25 GPa using Solartron 1260 Impedance/Gain‐Phase Analyzer in diamond anvil cell (DAC). The change in complex impedance related to the phase transition from wurtzite to rock salt was observed.Two distinct relaxation mechanisms were also identified. The effective scattering section of the grain boundary to charge carriers can be weakened under compression, which leads to the decrease of grain boundary resistance (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The ground electronic state of TiS2: experimental and theoretical studies
Authors: Liu Bao , Yang Jie , Liu Cailong , Hu Tingjing , Han Yonghao , Gao Chunxiao 
Published: March 2011

AbstractAn investigation of TiS2 electronic structure was conducted using a first‐principles calculation based on density functional theory (DFT). The results showed that there is indirect S3p ‐Ti3d band overlaps in ground electronic structure of TiS2. The measurements of resistivity and Hall effect were used to characterize the electrical transport behavior of TiS2 under ground state. Both theoretical and experimental results supported that TiS2 within ground state is a semimetal (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of grain boundary on resistance change in powdered ZnS under high pressure by in situ electrical impedance measurements
Authors: Wang Yue , Liu Cailong , Gao Yang , Wang Chunjie , Liu Bao , Hu Tingjing , Ren Wanbin , Han Yonghao , Gao Chunxiao 
Published: March 2011

AbstractThe effect of grain boundary on resistance in powdered ZnS under high pressure has been investigated by alternating current (ac) impedance spectrum method. Qualitative analysis indicated that the phase transition is accompanied by the shape transition of impedance spectrum which changed from two‐arc‐type to oblate‐like arc at 14.1 GPa. Above 11.0 GPa, the change of resistance is mainly contributed by grain boundary, and the residual resistance in rock‐salt phase ZnS is also comes from the grain boundary effect (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure modifications of oxide‐confined GaInNAs VCSELs for the second‐generation optical‐fibre communication
Authors: Sarzała Robert P. , Nakwaski Włodzimierz 
Published: March 2011

AbstractFor the second‐generation optical‐fibre communication, lasing sources emitting stable single‐fundamental‐mode (SFM) 1.3‐μm radiation are required. Then oxide‐confined GaAs‐based GaInNAs quantum‐well (QW) vertical‐cavity surface‐emitting lasers (VCSELs) seem to be the best solution. But possibility to reach their efficient 1.3‐μm low‐threshold SFM operation is usually questionable. Therefore the comprehensive fully self‐consistent simulation VCSEL model is used to find the most promising VCSEL structure for this application. It has been concluded from our analysis, that the best performance may be reached in the VCSEL structure in which the proper detuning of the cavity mode towards longer wavelengths and the proper step‐like active‐region QW structure are simultaneously applied. Then the stable 1.3‐μm SFM operation is reached for temperatures exceeding 305 K in the relatively large VCSEL with the 12‐μm diameter activity region. Its threshold current is only somewhat higher than 6 mA at the ambient temperature of 350 K. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The electrode factor on the accuracy of electrical resistivity measurement in diamond anvil cell
Authors: Wu Baojia , Han Yonghao , Peng Gang , Huang Xiaowei , Liu Cailong , Jin Fengxi , Gao Chunxiao 
Published: March 2011

AbstractThe four‐point method is widely used to determine the electrical resistivity of materials. Using finite element analysis (FEA) to simulate the distribution of the steady current field in sample, we illuminate the electrode factor on accurate resistivity measurement under high pressure in a diamond anvil cell (DAC). The result reveals that the measurement error is close dependent on the size and the resistivity of electrode. In order to minimize the measurement errors and improve the measurement accuracy, reducing the electrode size and increasing the electrode resistivity is a better choice. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of InN/In0.73Ga0.27N multiple quantum wells studied by spectroscopic ellipsometry
Authors: Ben Sedrine N. , Darakchieva V. , Lindgren D. , Monemar B. , Che S. B. , Ishitani Y. , Yoshikawa A. 
Published: March 2011

AbstractIn this work we study the optical properties of two high quality fifty‐periods of In‐polarity InN/In0.73Ga0.27N MQWs samples, grown by radio‐frequency plasma‐assisted molecular beam epitaxy, with different well (0.5‐1 nm) and barrier thicknesses (3‐4 nm). We employ spectroscopic ellipsometry at room temperature in the energy range from 0.6 to 6 eV, and incidence angles of 60 and 70°. Ellipsometric data were successfully modelled using the model dielectric function approach and a multilayer model assuming the MQWs as a homogeneous layer. The E0, A and E1 MQWs transition energies were determined and found to exhibit a blueshift with decreasing the well thickness. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
I‐V characterization of a staircase quantum well infrared photodetector
Authors: Nutku Ferhat , Arıkan M. Çetin , Erol Ayşe , Ergün Yüksel , Kendirlik E. Metin 
Published: March 2011

AbstractIn this work, a quantum well infrared photodetector structure which consists of three different well thicknesses with three different barrier compositions producing a staircase‐like conduction band profile with the reputation of 30 periods has been investigated. Dark current measurements have been done at the range from 6 K to 290 K temperature. Activation energies of the carriers have been obtained from the temperature dependence of the I‐V measurements. The change of the activation energy with bias voltage has also been obtained. From the activation energy at zero bias and calculated quasi Fermi energy, barrier heights of the quantum wells and ground state energies were obtained. All obtained ground state energies have been found to be consistent with the results obtained from calculations with the transfer matrix method. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tight binding modeling of electronic properties of III‐V based heterostructures
Authors: Akıncı Özden , Hakan Gürel H. , Ünlü Hilmi 
Published: March 2011

AbstractIn this work, we present second nearest neighbour (2NN) sp3s* and nearest neighbour (NN) sp3d5s* tight binding calculations, with spin‐orbit coupling to calculate the composition, temperature, pressure and strain effects on the electronic properties (e.g., band structure, density of states, band gaps and band widths) of GaAs, GaP, GaAN and AlN III‐V binaries and ternary GaPN. The results are compared with those of density functional theory for GaN. Our results are in good agreement with experiment for fundamental band gaps and electron effective masses. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)