bluuebunny/crossref_metadata_2025_split huggingface dataset:
DFT study of the ligand effects on the regioselectivity of the insertion reaction of olefins in the complexes [HRh(CO)2(PR3)(L)] (R = H, F, Et, Ph, OEt, OPh, and L = propene, styrene)
Authors: Dias Roberta P. , Prates Mauro S. L. , De Almeida Wagner B. , Rocha Willian R. 
Published: March 2010

AbstractIn this work, we have applied Density Functional Theory calculations to investigate the electronic and spacial effects of different phosphorus ligands on the selectivity of the olefin (propene and styrene) insertion reaction into the RhH bond of the complexes HRh(PR3)(CO)2(olefin), where the modified ligand PR3, is a phosphine (R = H, F, Et, Ph) or phosphite (R = OEt, OPh). M06/SBKJC/cc‐pVDZ calculations revealed that the olefin coordination and insertion reaction are dominated by the electronic effects of the phosphorus ligands. A very good correlation between the Tolman electronic factor, χ, with the backdonated charges from the metallic center to the olefin and also with the interaction energy of the olefin with the four‐coordinated HRh(CO)2(PR3) catalyst was found. Using the propene as the substrate and for all the phosphorus ligands investigated, the insertion always proceeds through the reaction path leading to the linear metal‐alkyl intermediate. However, when styrene is used, the branched metal‐alkyl intermediate is always favored. The structural results obtained for the transition states do not support the existence of a π‐allilic intermediates. The regioselectivity obtained for the insertion reaction of styrene results from thermodynamic aspects of the reaction in which the branched metal‐alkyl intermediate is always favored by ∼5 kcal/mol. The M06/SBKJC/cc‐pVDZ results are in good agreement with the experimental findings. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Efforts to improve detection sensitivity for capillary electrophoresis coupled to atmospheric pressure photoionization mass spectrometry
Authors: Axén Jakob , Malmström David , Axelsson Bengt‐Olof , Petersson Patrik , Sjöberg Per J. R. 
Published: March 2010

AbstractElectrospray ionization performs best with volatile buffers. However, generally the best separation performance for capillary electrophoresis (CE) is achieved with non‐volatile buffers. Hyphenation of CE with mass spectrometry (MS) utilizing atmospheric pressure photoionization (APPI) enables use of a wider range of separation buffers without compromising detection sensitivity. As APPI is considered to be mass flow sensitive, the use of a larger inner diameter separation capillary (75 µm) allows larger volumes to be injected, without decreased separation performance, thus providing improved sensitivity (approx. a factor of 10), compared to the use of a 25 µm capillary. However, nebulizing gas flow and position of capillary tip in the sprayer have to be carefully optimized to prevent excessive band broadening. Further improvement in sensitivity (approx. a factor of 2) was obtained by decreasing the distance between the sprayer and ionization region, indicating that a specially designed CE/APPI‐MS interface for low flow rates will be favourable. Copyright © 2010 John Wiley & Sons, Ltd.
Soil moisture effects on the carbon isotope composition of soil respiration
Authors: Phillips Claire L. , Nickerson Nick , Risk David , Kayler Zachary E. , Andersen Chris , Mix Alan , Bond Barbara J. 
Published: March 2010

AbstractThe carbon isotopic composition (δ13C) of recently assimilated plant carbon is known to depend on water‐stress, caused either by low soil moisture or by low atmospheric humidity. Air humidity has also been shown to correlate with the δ13C of soil respiration, which suggests indirectly that recently fixed photosynthates comprise a substantial component of substrates consumed by soil respiration. However, there are other reasons why the δ13CO2 of soil efflux may change with moisture conditions, which have not received as much attention. Using a combination of greenhouse experiments and modeling, we examined whether moisture can cause changes in fractionation associated with (1) non‐steady‐state soil CO2 transport, and (2) heterotrophic soil‐respired δ13CO2. In a first experiment, we examined the effects of soil moisture on total respired δ13CO2 by growing Douglas fir seedlings under high and low soil moisture conditions. The measured δ13C of soil respiration was 4.7‰ more enriched in the low‐moisture treatment; however, subsequent investigation with an isotopologue‐based gas diffusion model suggested that this result was probably influenced by gas transport effects. A second experiment examined the heterotrophic component of soil respiration by incubating plant‐free soils, and showed no change in microbial‐respired δ13CO2 across a large moisture range. Our results do not rule out the potential influence of recent photosynthates on soil‐respired δ13CO2, but they indicate that the expected impacts of photosynthetic discrimination may be similar in direction and magnitude to those from gas transport‐related fractionation. Gas transport‐related fractionation may operate as an alternative or an additional factor to photosynthetic discrimination to explain moisture‐related variation in soil‐respired δ13CO2. Copyright © 2010 John Wiley & Sons, Ltd.
The Malta cistern mapping project: Underwater robot mapping and localization within ancient tunnel systems
Authors: White Cory , Hiranandani Daniel , Olstad Christopher S. , Buhagiar Keith , Gambin Timmy , Clark Christopher M. 
Published: March 2010

AbstractThis paper documents the development of an underwater robot system enabled with several mapping and localization techniques applied to a particular archaeological expedition. The goal of the expedition was to explore and map ancient cisterns located on the islands of Malta and Gozo. The cisterns of interest acted as water storage systems for fortresses, private homes, and churches. Such cisterns often consisted of several connected chambers, still containing water. A sonar‐equipped remotely operated vehicle (ROV) was deployed into these cisterns to obtain both video footage and sonar range measurements. Six different mapping and localization techniques were employed, including (1) sonar image mosaics using stationary sonar scans, (2) sonar image mosaics using stationary sonar scans with Smart Tether position data, (3) simultaneous localization and mapping (SLAM) while the vehicle was in motion, (4) SLAM using stationary sonar scans, (5) localization using previously created maps, and (6) SLAM while the vehicle was in motion with Smart Tether position data. Top‐down‐view maps of 22 different cisterns were successfully constructed. It is estimated that the cisterns were built as far back as 300 B.C., and few records of their size, shape, and connectivity existed before the expedition. © 2010 Wiley Periodicals, Inc.
Preparation, modification and cellular evaluation of PEG–PEGd supports with titania nanoparticle loads
Authors: Vaquero Vanessa Sánchez , Noval Alvaro Muñoz , Sánchez Nuria Tejera , Pérez Roldán María Jesus , Valsesia Andrea , Ceccone Giaccomo , García Ruiz Josefa Predestinación , Manso Silván Miguel , Rossi Francois 
Published: March 2010

AbstractPolyethylene glycol (PEG) films with PEG diacrylate (PEGd) have been prepared comprising a Ti alkoxyde that turns the film into a nano‐hybrid with potential interest for the production of controlled bioadhesive surfaces. Precursor sols were cast onto Si (100) surfaces, producing conformed films. Modification of such surfaces was performed by exposing the surfaces to UV light (365 nm) at different exposure times. The surface of the hybrid films was characterized by using atomic force microscopy and X‐ray photoelectron spectroscopy. It is concluded that the UV exposure induces a densification of the film and an in‐film coalescence of the titania nanoparticles. This had a direct effect on the wettability of the films as determined by water contact angle measurements. Both as‐cast and UV modified surfaces were proved to be biocompatible as deduced from nuclear immunocytochemistry proliferation assays. Copyright © 2010 John Wiley & Sons, Ltd.
Fluoride concentration effect on the anodic growth of self‐aligned oxide nanotube array on Ti6Al7Nb alloy
Authors: Kaczmarek A. , Klekiel T. , Krasicka‐Cydzik E. 
Published: March 2010

AbstractThe formation of nanotube oxide layers on Ti6Al7Nb alloy in H3PO4 acid solutions containing fluoride ions is presented here. Among several parameters influencing the quality of nanotubes formed anodically such as potential, time of anodizing, fluoride ions concentration and scan rate of polarization, in particular, the last two seem to be the most responsible for the structure and morphology of nanotubes. The effect of fluoride ions concentration on the morphology of nanotubes on the two‐phase (α + β) Ti6Al7Nb implant alloy, has been evaluated in our work. The formation of nanotubes was performed by polarizing the Ti6Al7Nb alloy samples in 1 M H3PO4 containing 0.2%, 0.3% and 0.4% wt. Hydrofluoric acid (HF) to 20 V using scan rate 500 mV/s and then holding them at that potential for further 2 h in the same electrolyte. Nanotubes of diameter ranging from 50 to 80 nm, with thicker walls over β‐phase grains than over α‐phase grains, were obtained. During the formation process, which includes two stages–the first, potentiodynamic and the second, potentiostatic (20 V)–different electrochemical behavior was observed in electrolytes of various fluoride concentration. The clear relationship between the highest currents and the biggest diameter of nanotubes for 0.3% wt. HF containing electrolyte observed during the first stage of anodizing is explained with regard to electrochemical characteristics of alloying elements and transport of electrolyte anions in oxide layers. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of substrate surface topography on forensic development of latent fingerprints with iron oxide powder suspension
Authors: Jones B. J. , Downham R. , Sears V. G. 
Published: March 2010

AbstractLatent fingerprint deposition and effectiveness of detection are strongly affected by the surface on which prints are deposited. Material properties, surface roughness, morphology, chemistry and hydrophobicity can affect the usefulness or efficacy of forensic print development techniques. Established protocols outline appropriate techniques and sequences of processes for broad categories of operational surfaces. This study uses atomic force microscopy and scanning electron microscopy to investigate a series of surfaces classified as smooth, non‐porous plastic. Latent prints developed with iron oxide powder suspension are analysed on a range of scales from macro to nano to help elucidate the interaction mechanisms between the latent fingerprint, development agent and underlying surface. Differences between surfaces have a strong effect, even within this single category. We show that both average roughness and topographical feature shape, characterised by skew, kurtosis and lay, are important factors to consider for the processing of latent fingerprints. Copyright © 2010 John Wiley & Sons, Ltd.
Measurement of soil characteristics for forensic applications
Authors: Dawson Lorna A. , Hillier Stephen 
Published: March 2010

AbstractSoils may constitute evidence that connects a person or object to a particular location. The value of soil stems from its ubiquity and transferability to objects or persons. Due to the complexity of soil, the analysis of its inorganic and organic components can provide complementary and independent types of information about its geological origin, dominant vegetation, management and environment. We present an overview of a range of soil characterisation methods including chemical analysis, mineralogy and palynology, along with new approaches such as DNA profiling and profiling of other digital data such as that obtained from X‐ray powder diffraction, infrared spectroscopy and organic marker analysis.Individual analytical techniques have different scales of resolution and relevance depending on the nature of the criminal case and context. Each method has its strengths and weaknesses. As more methods have become digital and quantitative, their use in combination as digital profiles will help to characterise soils more accurately and at different scales. These new approaches can be tested using existing soil databases, and database development and use will help to refine and narrow probable origin of a questioned sample in police intelligence, as well as giving increasingly robust sample comparisons for evidence. Copyright © 2010 John Wiley & Sons, Ltd.
Nanostructures produced by SPM voltage ramping in metal oxide films
Authors: Bukauskas V. , Mironas A. , Šetkus A. , Strazdienė V. 
Published: March 2010

AbstractIn metal oxide film‐based nanosystems, the changes were produced and investigated by a scanning probe microscope (SPM). It is demonstrated that nanograins can be formed on the surfaces of ultrathin films (4 ÷ 10 nm) based on tin and indium oxides by the SPM electrical mode if the SPM tip is kept still on the surface and the bias voltage applied to the film is negative. In contrast to this, the positive bias voltage does not result in detectable changes of the film structures. The traceable transformations of the films are obtained only if the bias voltage exceeds a critical magnitude equal to about 2–3 V in SnO2 and about 5 V in In2O3. The nanograins are typically larger after a longer period of the electrical influence (typically 3 ÷ 5 min). The short‐term SPM analysis of the metal oxide surfaces during which a bias voltage is applied to the sample does not destroy the structure of the films in the tested points. The formation is faster and the nanogains are larger in the atmospheres with reduced amount of oxygen, e.g. in pure nitrogen, or with reducing gas, e.g. CO in air. The irreversible changes of the structure are shown being related to the hysteresis of voltamperic characteristics measured by the SPM before and during the initial stage of the grain formation. Based on this, the changes in the tin and indium oxides are explained by a redistribution of oxygen ions in the bulk of the films. Copyright © 2010 John Wiley & Sons, Ltd.
Surface analysis of cylinder liners from tribological model experiments and internal combustion engines
Authors: Tomastik C. , Jech M. , Wopelka T. , Franek F. 
Published: March 2010

AbstractHypereutectic aluminium‐silicon (AlSi) alloys have been increasingly used in the fabrication of internal combustion engines in recent years. They combine low weight with good mechanical properties and high wear resistance at the cylinder surface. Owing to the inhomogeneous structure of these alloys, the tribological processes taking place at the surface are highly complex. Therefore, interest in the tribological properties of the surfaces of these alloys has increased. Several tribological experiments with AlSi alloys have been reported in literature, as well as some surface analytical investigations. This work investigates the surfaces of AlSi alloy cylinder liners from an internal combustion engine and from a tribometer experiment. Surface hardness and elastic modulus were investigated with nanoindentation measurements, and the chemical composition of the surface was analyzed with XPS. The most striking difference between the samples from engine and tribometer was a layer of soot and residual lubricant on the Al matrix of the engine cylinder liner, whereas no such layer was found on the tribometer samples. This shows that the combustion process and its resulting products have a significant influence on the formation of tribolayers on the cylinder liner surface. Copyright © 2010 John Wiley & Sons, Ltd.
Properties of innovative resistive memories studied by X‐ray and UV photoemission
Authors: Martinez E. , Guedj C. , Calka P. , Minoret S. , Buckley J. , Bernard Y. , Jousseaume V. 
Published: March 2010

AbstractPt/NiO‐based devices are promising candidates for the next generation of resistive random access memories (RRAMs). X‐ray (XPS) and ultraviolet (UPS) photoemission are performed to investigate the chemical and electronic properties of this stack. After resistive switching of the nickel oxide, the as‐deposited and switched areas are compared in situ. The surface of the conductive area is characterised by a higher oxygen content as well as an enhancement of Ni3+ oxidation state, which can be related to defects such as Ni vacancies. The results are compatible with a bias‐induced diffusion of O2− towards the anode, and a migration of Ni2+ towards the cathode. The NiO electron affinity is estimated to be 1.6 eV by UPS in the OFF state, leading to a Pt/NiO barrier height of 3.6 eV. Copyright © 2010 John Wiley & Sons, Ltd.
Dead‐layer effect in silicon detectors: yield spectra of reflected electrons
Authors: Chaoui Zine‐El‐Abidine , Azli Tarek 
Published: March 2010

AbstractKnowledge of the exact energy deposited of keV and sub‐keV electron in solid‐state detectors with a dead layer depends strongly on the fraction of electrons backscattered and implanted. A new Monte Carlo (MC) simulation approach has been developed to describe electron scattering processes from silicon. In the present study, we show results concerning yield spectra of backscattered electrons. Backscattered fractions of primary, secondary and total yields are presented together with their energy spectra. Experimental databases of D. C. Joy and original experimental measurements recently made by K. Goto are used for comparison. Good agreement has been found suggesting the use of the present MC code to simulate a solid state silicon detector for low electron energies. Copyright © 2010 John Wiley & Sons, Ltd.
Auger electron from silicon: comparison of full Monte Carlo simulations with experiment
Authors: Chaoui Zine‐El‐Abidine , Goto Keisuké 
Published: March 2010

AbstractA Monte Carlo simulation approach has been developed to describe electron scattering processes from silicon in the keV and sub‐keV electron energy range. Ionizations, excitations, secondary electron production, relaxation and auger emissions are considered during the simulations. In the present study, we show results concerning K and L Auger electrons. Good agreement has been found when comparing our theoretical calculations and original experimental measurements recently made by Goto et al. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization of thin and ultrathin transparent conducting oxide (TCO) films and TCO‐Si interfaces with XPS, TEM and ab initio modeling
Authors: Diplas S. , Løvvik O. M. , Nordmark H. , M Kepaptsoglou D. , Graff J. Moe , Ladam C. , Tyholdt F. , Walmsley J. C. , Gunnaes A. E. , Fagerberg R. , Ulyashin A. 
Published: March 2010

AbstractInterfaces play an important role in solar cell heterostructures, especially when film thicknesses decrease. In this work, we use XPS, transmission electron microscopy (TEM) and density functional theory (DFT) to study both the film and the film–Si interface of electron beam deposited indium tin oxides (ITO) and pulsed laser deposition (PLD) deposited ZnO on p‐Si (100). Vacuum evaporation of ITO resulted in a film that contained elemental Sn and In which oxidized after annealing at 300 °C for 30 min. Ar etching of the HF‐treated Si substrate in the PLD deposition chamber caused an increase of the interfacial oxide thickness independently of the deposition temperature as a result of Ar etching‐induced dangling bonds. Deposition as well as annealing at elevated temperature also increases the interfacial oxide thickness for both ITO‐Si and ZnO‐Si systems. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization of P3HT/PCBM bulk heterojunction photovoltaic devices using advanced secondary ion mass spectrometry techniques
Authors: Audinot J.‐N. , Lévêque P. , Bechara R. , Leclerc N. , Guillot J. , Migeon H.‐N. , Hadziioannou G. , Heiser T. 
Published: March 2010

AbstractIn this work, we applied low‐impact energy secondary ion mass spectrometry (known as Sc‐Ultra SIMS) and high lateral resolution (NanoSIMS50) to characterize the P3HT/PCBM (poly(3‐hexylthiophene)/phenyl C61‐butyric acid methyl ester bulk heterojunction photovoltaic (PV) devices. Here we report results obtained on Al/P3HT:PCBM/PEDOT:PSS/ITO (poly(3‐hexylthiophene:phenyl C61‐butyric acid methyl ester/poly(ethylene‐dioxythiophene):poly(styrene sulfonate)/indium tin oxide) using advanced SIMS measurements to monitor 3D molecular compositions and metal/organic interface. The measurements have been performed on as‐deposited as well as‐annealed samples of Al/polymer interface. Blend macrophase separation and polymer/fullerene distribution have been investigated. Copyright © 2010 John Wiley & Sons, Ltd.
Ovarian cancer prediction in adnexal masses using ultrasound‐based logistic regression models: a temporal and external validation study by the IOTA group
Authors: Timmerman D. , Van Calster B. , Testa A. C. , Guerriero S. , Fischerova D. , Lissoni A. A. , Van Holsbeke C. , Fruscio R. , Czekierdowski A. , Jurkovic D. , Savelli L. , Vergote I. , Bourne T. , Van Huffel S. , Valentin L. 
Published: March 2010

AbstractObjectivesThe aims of the study were to temporally and externally validate the diagnostic performance of two logistic regression models containing clinical and ultrasound variables in order to estimate the risk of malignancy in adnexal masses, and to compare the results with the subjective interpretation of ultrasound findings carried out by an experienced ultrasound examiner (‘subjective assessment’).MethodsPatients with adnexal masses, who were put forward by the 19 centers participating in the study, underwent a standardized transvaginal ultrasound examination by a gynecologist or a radiologist specialized in ultrasonography. The examiner prospectively collected information on clinical and ultrasound variables, and classified each mass as benign or malignant on the basis of subjective evaluation of ultrasound findings. The gold standard was the histology of the mass with local clinicians deciding whether to operate on the basis of ultrasound results and the clinical picture. The models' ability to discriminate between malignant and benign masses was assessed, together with the accuracy of the risk estimates.ResultsOf the 1938 patients included in the study, 1396 had benign, 373 had primary invasive, 111 had borderline malignant and 58 had metastatic tumors. On external validation (997 patients from 12 centers), the area under the receiver–operating characteristics curve (AUC) for a model containing 12 predictors (LR1) was 0.956, for a reduced model with six predictors (LR2) was 0.949 and for subjective assessment was 0.949. Subjective assessment gave a positive likelihood ratio of 11.0 and a negative likelihood ratio of 0.14. The corresponding likelihood ratios for a previously derived probability threshold (0.1) were 6.84 and 0.09 for LR1, and 6.36 and 0.10 for LR2. On temporal validation (941 patients from seven centers), the AUCs were 0.945 (LR1), 0.918 (LR2) and 0.959 (subjective assessment).ConclusionsBoth models provide excellent discrimination between benign and malignant masses. Because the models provide an objective and reasonably accurate risk estimation, they may improve the management of women with suspected ovarian pathology. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.