bluuebunny/crossref_metadata_2025_split huggingface dataset:
Eigenfrequency and decay factor of the localized torsional phonon in a nanowire superlattice with a defect layer
Authors: Mizuno Seiji 
Published: November 2009

AbstractWe theoretically study the localized vibrational modes in a cylindrical nanowire superlattice with a defect layer. We focus on torsional modes whose dispersion relations can be obtained analytically. We calculate the eigenfrequencies of the localized mode and corresponding decay factor. In particular, we examined how the eigenfrequencies depend on the width of the defect layer. It is shown that the localized modes cannot exist below a critical frequency due to the effect of the radial confinement of phonons. We also study the resonant transmission of acoustic phonons as a result of the interaction with these localized modes. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrational modes in a square cross‐section InAs/InP nanowire superlattice
Authors: Mizuno Seiji , Nakamura Yushi 
Published: November 2009

AbstractWe study theoretically the phonon modes in a square cross‐section nanowire superlattice (NWSL) consisting of InAs and InP. The phonon modes in the NWSL composed of cubic materials are classified into five types, i.e., A1, A2, B1, B2, and E modes. We calculate the dispersion relations of each phonon mode and corresponding displacement fields for this NWSL. The A1, A2, B1, B2, and E modes have features of dilatational, torsional, stretching, shear, and flexural modes, respectively. We examine the effects of both the superlattice modulation along the wire axis and lateral confinement of phonons. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorption of benzene over the rutile TiO2 (110) surfaces: A theoretical study
Authors: Neto A. R. R. , Alves H. W. Leite 
Published: November 2009

AbstractIn this work, we present our theoretical results for the relaxation of the rutile TiO2 (110), as well as for the adsorption of benzene over this surface. Our results are in good agreement with both the available theoretical and experimental data, whenever these comparisons were possible. Based on our obtained results, we show that the interaction between the adsorbate and the TiO2 (110) surface shows a van der Waalslike character, with the calculated adsorption energies at the order of 43 to 173 meV. In this adsorption process, the H atoms of the benzene prefer to bind with the surface Ti atoms. As a result, two occupied electronic levels appear at the surface bandgap, which are responsible for the optical absorption peaks at the blue‐violet region of the electromagnetic spectra. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐plane optical anisotropy of copper‐phthalocyanine films: RAS studies and modelling
Authors: Fronk Michael , Zahn Dietrich R. T. , Salvan Georgeta 
Published: November 2009

AbstractCopper‐phthalocyanine (CuPc) films prepared by organic molecular beam deposition on H‐passivated silicon and Si covered with native oxide were investigated by means of ellipsometry and reflection anisotropy spectroscopy (RAS). In addition to the out‐of‐plane anisotropy found from the evaluation of the ellipsometry data (Aspnes and Studna, Phys. Rev. Lett. 54, 1954 (1985) [1]) an in‐plane anisotropy in the order of 10‐2 was detected by RAS. In a first step model calculations assuming homogeneous in‐plane anisotropy over the whole layer thickness were performed in order to extract the anisotropy of the optical constants n and k.In a second step, more advanced models taking into account a change in the anisotropy with film thickness were constructed in order to describe the in‐plane anisotropy spectral evolution with film thickness. For the films on Si/SiO2 the in‐plane anisotropy is found to increase with increasing thickness. On H‐Si this effect is not observed and the behaviour of CuPc is more complicated to model on this substrate. Thus, the interaction of the molecules with the differently treated substrate surfaces plays a crucial role for the molecular alignment. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorption of lead phthalocyanine on the hydrogen‐passivated Ge(001)‐2x1 surface
Authors: Holland B. N. , Gavrila G. , Zahn D. R. T. , Cafolla A. A. , McGuinness C. , McGovern I. T. 
Published: November 2009

AbstractThe adsorption of lead phthalocyanine (PbPc) on the hydrogen passivated Ge(001)‐2×1 surface is investigated by photoelectron spectroscopy, scanning tunnelling microscopy and near‐edge absorption fine structure (NEXAFS) techniques. The substrate‐molecule interaction is observed to be weak, with the molecule‐molecule interaction predominantly determining the ordering at the interface. The molecules in the first observable islands adopt a crystal structure similar to the bulk triclinic structure, with the stacking axis parallel to the substrate. Adlayers are ∼0.8 nm in height and the average tilt in thicker layers, as determined by NEXAFS, is consistent with this crystal structure. However, the first island height observed is ∼1.6 nm, which is considered to be a bilayer of PbPc molecules; the average tilt in these initial layers is slightly larger. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interaction of GaN(0001)‐2×2 surfaces with H2O
Authors: Lorenz P. , Gutt R. , Haensel T. , Himmerlich M. , Schaefer J. A. , Krischok S. 
Published: November 2009

AbstractWe performed an in‐situ analysis of the interaction of water with clean 2×2 reconstructed GaN(0001) surfaces grown by plasma assisted molecular beam epitaxy. The as‐grown surfaces were exposed to molecular water by backfilling. Photoemission spectra reveal an extremely high reactivity and dissociative adsorption with an oxygen sticking coefficient of 0.3 and a saturation coverage of approximately 1 ML. Core level spectra of the O1s state show three individual oxygen components with different temporal behavior. Furthermore, the initial reconstruction quickly vanishes and surface states in the valence band of the as‐grown surface are removed during the exposure of the first few Langmuirs. For higher exposures, two oxygen‐related states appear. The initial upward band bending of 0.4 eV for the as‐grown surface is effectively reduced during oxidation resulting in flat band conditions. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinetics of albumin homocysteinylation measured with matrix‐assisted laser/desorption ionization mass spectrometry versus with a radioactive tracer
Authors: Callegher Elisabetta , Seraglia Roberta , Vettore Monica , Puricelli Lucia , Millioni Renato , Tessari Paolo 
Published: November 2009

AbstractHomocysteinylation is a post‐translational protein modification which involves homocysteine‐thiolactone and may be responsible for many pathophysiological changes secondary to hyperhomocysteinemia. Therefore, methods to measure protein homocysteinylation in intact biological samples are required. We tested whether matrix assisted‐laser/desorption ionization mass spectrometry (MALDI‐MS) can detect time‐ and dose‐dependent changes in in vitro homocysteine‐thiolactone binding to human serum albumin. We have compared this method with a 35S‐thiolactone radioactive binding assay. Incubations with and without dithiothreitol allowed measurement of the amide‐linked and disulfide‐linked thiolactone‐protein adducts, respectively. A good correspondence in time‐ and dose‐dependent protein‐thiolactone formation was observed between the two methods. A maximum of 9 to 12 thiolactone residues were bound to each albumin molecule. The 35S‐thiolactone bound albumin tightly, particularly at the lowest concentrations, with ≈70% of the binding amide‐linked. Although the results of the two methods were rather similar, the radioactive method appears to be more sensitive than the MALDI‐MS technique. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of a series of isomeric oligosaccharides by energy‐resolved mass spectrometry: a challenge on homobranched trisaccharides
Authors: Daikoku Shusaku , Widmalm Göran , Kanie Osamu 
Published: November 2009

AbstractGlycans exist as part of glycoproteins and glycolipids, which are involved in a variety of biological functions. The analysis of glycan structures, particularly that of structural isomers, is fundamentally important since isomeric glycans often show distinct functions; however, a method for their structural elucidation has not yet been established. Anomeric configurations, linkage positions and branching are the major factors in glycans and their alteration results in a large diversity of glycan structures. The analysis of vicinally substituted oligosaccharides is extremely difficult because the product ions formed in tandem mass spectrometry (MS/MS) often have the same m/z values. In our endeavor to address the issue, we analyzed a series of homo‐substituted trisaccharides consisting only of glucose by collision‐induced dissociation (CID), especially energy‐resolved mass spectrometry (ERMS). It was found that these structurally related glycans could be distinguished by taking advantage of differences in their activation energies in ERMS. Copyright © 2009 John Wiley & Sons, Ltd.
Control of origin of larch wood: discrimination between European (Austrian) and Siberian origin by stable isotope analysis
Authors: Horacek Micha , Jakusch Michael , Krehan Hannes 
Published: November 2009

AbstractMost of the coniferous wood of non‐European origin that is imported into the European Union (EU) has to be inspected phytosanitarily, to prevent the introduction and spread of harmful pests in EU territory. Wood importers have been caught declaring Siberian larch wood as being of European origin to save the costs of the inspection. Therefore, an unequivocal method has to be developed in addition to the traditional analysis of the tree ring density to identify incorrect declarations of larch wood origin. For this purpose, δ18O and δ13C analyses have been carried out to check if Siberian larch wood can be discriminated from European larch. Measurements have been carried out on bulk wood samples, as the method has to be designed to be as simple as possible. The results show an overlapping of the Siberian and Austrian δ13C, and no overlapping for the δ18O values. Copyright © 2009 John Wiley & Sons, Ltd.
Online nanoelectrospray/high‐field asymmetric waveform ion mobility spectrometry as a potential tool for discovery pharmaceutical bioanalysis
Authors: Hatsis Panos , Valaskovic Gary , Wu Jing‐Tao 
Published: November 2009

AbstractNanoelectrospray ionization (nESI) coupled online with high‐field asymmetric waveform ion mobility spectrometry (FAIMS) for small molecule analysis in a discovery pharmaceutical setting was examined. A conventional capillary pump, autosampler and nESI source were used to introduce samples directly into the FAIMS device. The FAIMS device was used to separate gas‐phase ions on a timescale that was compatible with the mass spectrometer. The capability of the nESI‐FAIMS combination to efficiently remove metabolite interferences from the parent drug, and reduce ion suppression effects, was demonstrated. On average, 85% of the signal intensity obtained from a neat sample was preserved in the extracted plasma samples. Standard curves were prepared for several compounds. Linearity was obtained over approximately 3 to 4 orders of magnitude. Comparison of results from nESI‐FAIMS with those from conventional LC/MS for a mouse pharmacokinetic study yielded concentration values differing by no more than 30%. Copyright © 2009 John Wiley & Sons, Ltd.
Mass spectrometry and UV‐VIS spectrophotometry of ruthenium(II) [RuClCp(mPTA)2](OSO2CF3)2 complex in solution
Authors: Peña‐Méndez Eladia María , González Beatriz , Lorenzo Pablo , Romerosa Antonio , Havel Josef 
Published: November 2009

AbstractRuthenium(II) complexes are of great interest as a new class of cancerostatics with advantages over classical platinum compounds including lower toxicity. The stability of the [RuClCp(mPTA)2](OSO2CF3)2 complex (I) (Cp cyclopentadienyl, mPTA N‐methyl 1,3,5‐triaza‐7‐phosphaadamantane) in aqueous solution was studied using spectrophotometry, matrix‐assisted laser desorption/ionization (MALDI) and laser desorption/ionization (LDI) time‐of‐flight (TOF) mass spectrometry (MS). Spectrophotometry proves that at least three different reactions take place in water. Dissolution of I leads to fast coordination of water molecules to the Ru(II) cation and then slow hydrolysis and ligand exchange of chloride and mPTA with water, hydroxide or with trifluoromethane sulfonate itself. Via MALDI and LDI of the hydrolyzed solutions the formation of singly positively charged ions of general formula RuClp(Cp)q(mPTA)r(H2O)s(OH)t (p = 0–1, q = 0–1, r = 0–2, s = 0–5, t = 0–2) and of some fragment ions was shown. The stoichiometry was determined by analyzing the isotopic envelopes and computer modelling. The [RuClCp(mPTA)2](OSO2CF3)2 complex can be stabilized in dilute hydrochloric acid or in neutral 0.15 M isotonic sodium chloride solution. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of low‐concentration gas samples with continuous‐flow isotope ratio mass spectrometry: eliminating sources of contamination to achieve high precision
Authors: Cambaliza Maria O. L. , Harlow Benjamin A. , Ubierna Nerea , Mount George H. , Marshall John D. , Evans R. David 
Published: November 2009

AbstractDevelopments in continuous‐flow isotope ratio mass spectrometry have made possible the rapid analysis of δ13C in CO2 of small‐volume gas samples with precisions of ≤0.1‰. Prior research has validated the integrity of septum‐capped vials for collection and short‐term storage of gas samples. However, there has been little investigation into the sources of contamination during the preparation and analysis of low‐concentration gas samples. In this study we determined (1) sources of contamination on a Gasbench II, (2) developed an analytical procedure to reduce contamination, and (3) identified an efficient, precise method for introducing sample gas into vials. We investigated three vial‐filling procedures: (1) automated flush‐fill (AFF), (2) vacuum back‐fill (VBF), and (3) hand‐fill (HF). Treatments were evaluated based on the time required for preparation, observed contamination, and multi‐vial precision. The worst‐case observed contamination was 4.5% of sample volume. Our empirical estimate showed that this level of contamination results in an error of 1.7‰ for samples with near‐ambient CO2 concentrations and isotopic values that followed a high‐concentration carbonate reference with an isotope ratio of −47‰ (IAEA‐CO‐9). This carry‐over contamination on the Gasbench can be reduced by placing a helium‐filled vial between the standard and the succeeding sample or by ignoring the first two of five sample peaks generated by each analysis. High‐precision (SD ≤0.1‰) results with no detectable room‐air contamination were observed for AFF and VBF treatments. In contrast, the precision of HF treatments was lower (SD ≥0.2‰). VBF was optimal for the preparation of gas samples, as it yielded faster throughput at similar precision to AFF. Copyright © 2009 John Wiley & Sons, Ltd.
Bayesian modeling of multivariate spatial binary data with applications to dental caries
Authors: Bandyopadhyay Dipankar , Reich Brian J. , Slate Elizabeth H. 
Published: November 2009

AbstractDental research gives rise to data with potentially complex correlation structure. Assessments of dental caries yield a binary outcome indicating the presence or absence of caries experience for each surface of each tooth in a subject's mouth. In addition to this nesting, caries outcome exhibit spatial structure among neighboring teeth. We develop a Bayesian multivariate model for spatial binary data using random effects autologistic regression that controls for the correlation within tooth surfaces and spatial correlation among neighboring teeth. Using a sample from a clinical study conducted at the Medical University of South Carolina, we compare this autologistic model with covariates to alternative models to demonstrate the improvement in predictions and also to assess the effects of covariates on caries experience. Copyright © 2009 John Wiley & Sons, Ltd.
An investigation of the MC‐SIMEX method with application to measurement error in periodontal outcomes
Authors: Slate Elizabeth H. , Bandyopadhyay Dipankar 
Published: November 2009

AbstractMeasurement error is pervasive in medical research. In periodontal research studies, one measure of disease status is the probed pocket depth (PPD), the depth of the space between a tooth and the surrounding gum. In larger studies, these assessments are made by multiple examiners, each having distinct measurement error characteristics. Because PPD is recorded in whole millimeters, it may be regarded as discrete and its associated error as misclassification error. This study investigates the impact of this measurement error when evaluating the effect of periodontal disease status on levels of inflammatory markers in gingival crevicular fluid (GCF). The marker readings are either left or right censored, due to quantities that are either too small to be reliably quantified or so large that they saturate the detector. Additionally, marker readings from multiple periodontal sites within a subject's mouth are correlated. These considerations give rise to a clustered survival model for the marker readings in which the discrete predictor of interest is misclassified. Associations between the GCF markers and periodontal assessments are corrected for misclassification error using the MC‐SIMEX method. Simulation studies reveal the impact of varying degrees of misclassification error on associations of interest. Analysis of pilot data from a periodontal study, for which examiner misclassification rates are estimated from calibration studies, further illustrates the approach. Copyright © 2009 John Wiley & Sons, Ltd.
Adapting Häävikko's dental age for the assessment of Italian children: use of LMS and other models based on smoothing splines
Authors: Spada Elena , Butti Andrea Carlo , Ferraroni Monica , Milani Silvano 
Published: November 2009

AbstractThe expression ‘dental age’ (DA) denotes the mean age at which a given stage of dental development is achieved in a population chosen as calibrator. The rhythm at which the maturation occurs is a characteristic of a given population in a given period. When DA is determined on subjects of a population different from the calibrator, the shape of the relationship of DA to chronological age (CA) must be empirically determined to trace reference charts for DA that properly apply to this population. The aim of this study is to show how the DA determined in a calibration set (Häävikko's DA) can be adapted to apply to another population (Italian children), by means of CA‐dependent smooth functions of the location, scale and shape of DA distribution. A set of 492 good quality panoramic films taken on healthy Italian children aged 5.5–14.5 years was analysed. The techniques under comparison produced quite similar curves: a parsimonious (4 e.d.f.) and rather satisfactory smoothing spline was found for median, but not for scale and shape indices: so the meaning of SDS values derived from these adjusted reference charts may result doubtful. Among the software products considered here, LMS program was found to be particularly user friendly, since allows the user to visually control the effect of changing the number of e.d.f. on the pattern of DA reference charts. Copyright © 2009 John Wiley & Sons, Ltd.
Three‐dimensional ultrasound imaging for discrimination between benign and malignant endometrium in women with postmenopausal bleeding and sonographic endometrial thickness of at least 4.5 mm
Authors: Opolskiene G. , Sladkevicius P. , Jokubkiene L. , Valentin L. 
Published: November 2009

AbstractObjectivesTo determine whether endometrial volume or power Doppler indices as measured by three‐dimensional (3D) ultrasound imaging can discriminate between benign and malignant endometrium, to compare their diagnostic performance with that of endometrial thickness measurement using two‐dimensional (2D) ultrasound examination, and to determine whether power Doppler indices add any diagnostic information to endometrial thickness or volume.MethodsSixty‐two patients with postmenopausal bleeding and endometrial thickness ≥ 4.5 mm underwent transvaginal 2D gray‐scale and 3D power Doppler ultrasound examination of the corpus uteri. The endometrial volume was calculated, along with the vascularization index (VI), flow index and vascularization flow index (VFI) in the endometrium and in a 2‐mm ‘shell’ surrounding the endometrium. The ‘gold standard’ was the histological diagnosis of the endometrium obtained by hysteroscopic resection of focal lesions, dilatation and curettage or hysterectomy. Receiver–operating characteristics (ROC) curves were drawn for all measurements to evaluate their ability to distinguish between benign and malignant endometrium. Multivariate logistic regression analysis was used to create mathematical models to estimate the risk of endometrial malignancy.ResultsThere were 49 benign and 13 malignant endometria. Endometrial thickness and volume were significantly larger in malignant than in benign endometria, and flow indices in the endometrium and endometrial shell were significantly higher. The area under the ROC curve (AUC) of endometrial thickness was 0.82, that of endometrial volume 0.78, and that of the two best power Doppler variables (VI and VFI in the endometrium) 0.82 and 0.82. The best logistic regression model for predicting malignancy contained the variables endometrial thickness (odds ratio 1.2; 95% CI, 1.04–1.30; P = 0.004) and VI in the endometrial ‘shell’ (odds ratio 1.1; 95% CI, 1.02–1.23; P = 0.01). Its AUC was 0.86. Using its mathematically optimal risk cut‐off value (0.22), the model correctly classified seven more benign cases but two fewer malignant cases than the best endometrial thickness cut‐off (11.8 mm). Models containing endometrial volume and flow indices performed less well than did endometrial thickness alone (AUC, 0.79 vs. 0.82).ConclusionsThe diagnostic performance for discrimination between benign and malignant endometrium of 3D ultrasound imaging was not superior to that of endometrial thickness as measured by 2D ultrasound examination, and 3D power Doppler imaging added little to endometrial thickness or volume. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Sonographic identification of lower limb venous hypoplasia in the prenatal diagnosis of Klippel–Trénaunay syndrome
Authors: Coombs P. R. , James P. A. , Edwards A. G. 
Published: November 2009

AbstractWe report the prenatal identification of lower‐limb venous hypoplasia to support a provisional prenatal diagnosis of Klippel–Trénaunay syndrome (KTS). Ultrasound assessment of a fetus with marked lower‐limb edema, cystic areas in the abdomen/pelvis/lower limbs and abnormal development of the feet demonstrated bilateral hypoplasia of the femoral and popliteal veins. The external iliac veins and the great saphenous veins were seen to be normal. The lower limb arterial system was present. These findings supported KTS as the most likely provisional diagnosis, and postnatal clinical evaluation confirmed that the infant is best classified in the spectrum of KTS. Venous hypoplasia was confirmed with a postnatal ultrasound examination of the lower limbs. This case suggests that careful examination of the lower‐limb venous system may be helpful in making the prenatal diagnosis of KTS. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.