bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation of barium on the surface of nanothick chromium oxide films grown on the (110) molybdenum substrate
Authors: Klimenko E.V. , Starovojtova L.N. , Zasimovich I.N. , Naumovets A.G. 
Published: April 2009

AbstractAuger electron spectroscopy and work function measurements were used to investigate adsorption of barium onto the surface of nanothick chromium oxide films grown on the (110) molybdenum substrate. We prepared smooth 3‐monolayers (ML) thick pseudomorphic chromium oxide films and rough 2–3 ML chromium oxide films carrying three‐dimensional oxide nanoparticles (the Stranski‐Krastanov (SK) surface morphology). The interaction of barium with chromium oxide films of both types was found to lead to barium oxide formation and partial reduction of chromium oxide to chromium. When barium was deposited onto a 3 ML pseudomorphic chromium oxide film, the barium oxidation at room temperature was restricted to formation of only one monolayer of barium oxide. However, in the case of barium adsorption on chromium oxide film with the SK type surface morphology, the oxidation encompassed 3 monolayers of barium. A strong effect of metal substrate‐oxide film interface on the oxidation ability of nanothick oxide films was revealed. These results showed possibilities of tailoring surface properties of the barium oxide films by variation of their thickness and by substrate‐film interface modification.
Photoluminescence effects on gold nano‐ particles modified by short single stranded DNA molecules
Authors: Kysil O. , Simonova K. , Frolov V. , Buzaneva E. , Köhler M. , Gobsch G. , Ritter U. , Scharff P. 
Published: April 2009

AbstractThe concept for a function of gold nanoparticle photosensor based on gold nanoparticle optical properties, depending on the size and architecture of their self – assemblies, is revised from the studies of modified by short ssDNA (5.4 nm length) selected gold nanoparticle (8.6 nm diameter) assembling in biosuspensions. Biosensing effect, collective photoluminescence in visible range of different size 2D, 3D assemblies from these nanoparticles, is revealed due to their controlled assembling in biosuspesions, dependent on ssDNA conformation, that changes gold core capping and therefore a force of interparticle interaction. Nanophotosensor is characterized by intensive photoluminescence maxima in two regions of visible range for tested biosuspensions due to detected difference in the self ‐ assemblies’ architecture of gold nanoparticles with different gold core capping by the ssDNA molecules. The emission maxima are 4.2x103pps and 4.1x104pps in (525–780) nm and (780–920) nm regions mainly for 2D assemblies as nanowires and 3D assemblies as circle holms, correspondently, in DNA buffer suspensions with different biomolecules. The results are explained addressing photoluminescence of gold nanoparticle assemblies to system of discrete electron states in valence and conductivity bands for gold nanoparticle model.
SQUID‐imaging technology to study magnetic nanocarriers for targeted magnetic transport
Authors: Budnyk M.M. , Dudchenko N.O. , Stavynska O.M. , Alekseytsev Y.O. , Dudchenko O.K. , Chaikovsky I.A. , Minov Y.D. , Sutkovyi P.G. , Shpylyovy P.B. , Ryzhenko T.M. , Budnyk V.M. , Voytovych I.D. 
Published: April 2009

AbstractThe aim of the study was to develop SQUID‐magnetometer system and to reveal the ability of above system to monitor the dynamics of injected magnetic nanoparticles (MNP) into rabbit’s body. MNP were prepared by first precipitation of ferrous hydroxide which was then crystallized into magnetite in the presence of potassium nitrate as mild oxidizing agent and further the MNP surface was modified with oxidized hidroxyethylstarch. The dynamics of the MNP distribution into the rabbit tissues according to the electron‐spin resonance (ESR) data shows that after 60 min of nanomaterial preparation circulation into the rabbit’s body the preparation redistribution occurs in favor of liver and spleen. The magnetic field applying to the kidneys area leads to the considerable increase of iron concentration in kidneys. As a result of magnetic fields measurements over the rabbit with injected MNP using developed SQUID‐magnetometry system, the maps of MNP spatial distribution into the rabbit’s body were obtained.
Interaction of carbon nanotubes containing iron catalysts and iron‐based powders with human blood plasma
Authors: Ivashchenko O. , Boshytska N. , Uvarova I. , Prylutskyi E. 
Published: April 2009

AbstractWhen nanotubes containing a metallic catalyst enter a living organism through the respiratory apparatus, they may interact with tissue fluid and blood. We describe the estimation of the activity of the catalyst nanoparticles in the interaction with such biomedia in comparison to iron‐based powders. The interaction of iron‐carbon nanotubes, carbonyl iron and iron (III) oxide with human blood and tissue fluid was modelled. The amount of iron released into the biomedia was determined using a spectral photometric method. The nanotubes released almost the same amount of iron into the plasma‐containing media as the carbonyl iron (34.67 mg/0.5 g and 38.92 mg/0.5 g, respectively), despite the fact that the carbonyl iron contained 99.3 wt % iron whereas the nanotubes contained only 33.5 wt %. Carbonyl iron powder interacted with blood plasma 180 times more compared to iron (III) oxide powder. This suggests that α‐iron is assimilated (i.e. it dissolves and gets biotransformed) by blood plasma easier and faster than iron (III) oxide. We conclude that the dominant contribution in the iron released from nanotubes into blood plasma is made by iron (III) oxide. The high concentration of iron (close to that of carbonyl iron) in blood plasma may be ascribed to the nanoscale nature of iron (III) oxide particles.
Effect of exogenous carbon nanoparticles on structure and reinforcement of aluminum matrix composite
Authors: Demchenko I.I. , Stovpchenko G.P. 
Published: April 2009

AbstractThe possibility of carbon nanotubes (CNT) using as strengthening phase in aluminum‐matrix composite is represented in the present work both theoretically and practically. The hardness which was determined in obtained samples using Vickers method is reduced in one graph. This graph quantitively represents the increasing hardness. The mechanism of the obtained composites hardening was explained using the classical laws of hardening theory. The maximal concentration of CNT in metal matrix under the highest composite hardening was calculated.
Investigation of the improvement of the physical and mechanical properties of polymer composite materials with nano‐sized powders
Authors: Bilogurova L. , Shevtsova M. 
Published: April 2009

AbstractPolymer composites are widely applied in modern aviation. However, their shortcomings force scientists to look for material enhancing methods. Therefore experimental research of the influence of nanoparticles on the polymer strength and the electromagnetic properties was conducted. The polymer modification was realized by two kinds of nano‐sized powders: iron and diamond. The addition of 0.67 % nanodiamonds mass content in polymer increases its strength (about 2 times). This can be explained by electrical interaction of nanoparticles with high specific surface energy and monomer molecules having dipole moments. The samples for dielectric permittivity measuring were made from pure resin and from resin reinforced with 0.67 % nanodiamonds and 1 % nano‐iron mass content. The results show that the addition of nanodiamonds decreases the resin dielectric permittivity but nano‐iron addition increases it. The electrical conductivity σ and the magnetic permeability μ were measured on samples with 1 %, 3 %, 10 % and 25 % weight content of nanoscale iron. The electrical conductivity did not uniformly increase according to the percolation theory. This percolation transition (by 5 orders of magnitude) corresponds to nano‐iron mass content 3 %.
Detection of dying cells using lectin‐conjugated fluorescent and luminescent nanoparticles
Authors: Bilyy R. , Tomyn A. , Kit Y. , Podhorodecki A. , Misiewicz J. , Nyk M. , Strek W. , Stoika R. 
Published: April 2009

AbstractConstantly increasing sector of industry of biomedical diagnostics requires photosensitive and stable nanomaterials which can be specifically bio‐labeled for targeting selected cells in the body. Here we describe two types of novel nanomaterials conjugated with specific proteins recognized by dying (apoptotic and necrotic) cells. They are luminescent GaN:Eu3+‐doped nanoparticles with wide green emission and very narrow red emission and fluorescent green‐emitting fluorescein‐containing polystyrene nanoparticles. These nanoparticles were conjugated with carbohydrate recognizing proteins – the lectins – that are targeting specific cell surface glycoproteins which were recently shown to be novel markers of dying cells (Bilyy et al., 2003, Bilyy et al., 2007). Both luminescent and fluorescent nanoparticles possessed high brightness and low level of photobleaching and efficiently interacted with dying cells, thus discriminating them from the intact ones.
Comparative study of biological action of fullerenes C60 and carbon nanotubes in thymus cells
Authors: Prylutska S.V. , Grynyuk I.I. , Grebinyk S.M. , Matyshevska O.P. , Prylutskyy Y.I. , Ritter U. , Siegmund C. , Scharff P. 
Published: April 2009

AbstractIn a model experiment on T‐cells isolated from Wistar rat thymus the biological activity of nonmodified fullerenes (C60) and multi‐walled carbon nanotubes (MWCNT) is studied. It is demonstrated that C60 at a concentration of 14.4 μg/ml in the cell incubation medium inhibit the activity of plasma membrane Ca2+‐stimulated ecto‐ATPase. Both, the initial rate of the extracellular ATP hydrolysis and the time of reaching the half‐maximum level of the enzyme activity are decreased, while MWCNT (12.5 and 25 μg/ml) have no effect on the kinetic parameters of the ecto‐ATPase reaction. It is shown that both C60 and MWCNT demonstrate a protective effect against H2O2‐induced injury of thymic T‐cells.
Mechanism of thermal and electrical conductivity in polymer‐nanocarbon composites
Authors: Lazarenko A. , Vovchenko L. , Prylutskyy Y. , Matzuy L. , Ritter U. , Scharff P. 
Published: April 2009

AbstractThe electrical and thermal conductivity of nanocarbon filled polymers were studied by adding nanocarbon fillers (thermoexfoliated graphite (TEG) and dispersed TEG (nanoTEG)) to epoxy resin (ED) or polyethylene oxide (PEO). The content of filler in composite materials (CM) was (0.5–10) wt%. The temperature range of the investigations was (77–300) K for electrical conductivity and (150–423) K for thermal conductivity, respectively. It was found that electrical conductivity of CM obeys percolation dependence with low critical concentration cr∼(1–2) wt% (φcr∼(0.56–1.1) vol%) and characterised by a positive temperature coefficient. The thermal conductivity is approximately linear on nanocarbon content. The model describing the mechanisms of electrical and thermal conductivity of CM had been proposed. The basic parameters of this model are following: content of nanocarbon anisotropic particles and their distribution in polymer matrix; the contact thermal (electrical) resistance both between the filler particles and on the interface of two phases – polymer‐carbon filler.
Sources of highly charged ions as a platform technology for applications in nanotechnology and medicine
Authors: Zschornack G. , Grossmann F. , Ovsyannikov V.P. , Heller R. , Kentsch U. , Kreller M. , Schmidt M. , Schwan A. , Silze A. , Ullmann F. 
Published: April 2009

AbstractHighly charged ions significantly differ in their physical properties compared to “classical” low charged ions. With the Dresden EBIT/EBIS family (EBIT: Electron Beam Ion Trap, EBIS: Electron Beam Ion Source) a compact, economic and long‐term stable source setup for highly charged ions is available providing the platform technology for various applications. Beside the use in basic as well as in applied research this technology is also suitable for nanotechnology and medical applications. Potential applications and first proof‐of‐principle experiments are discussed. The integration of an EBIT in a FIB setup is exemplified.
Tax‐avoidance strategies of American multinationals: an empirical analysis
Authors: Schwarz Peter 
Published: April 2009

AbstractThis paper analyzes the opportunities of American multinationals to reallocate their profits into tax havens. In contrast to previous papers, a comprehensive look on the profit‐shifting process is undertaken by proposing three different tests. Multinationals in high‐tax countries have a lower equity ratio than affiliates in tax havens, indicating that income is shifted by extensively financing subsidiaries in high‐tax countries with debt. Furthermore, the share of retained earnings is lower in high‐tax countries owing to the unattractiveness of tax deferral. When testing for the outcomes of profit shifting, the results show that the pre‐tax profitability of American multinationals is higher in tax havens. This relationship is consistent with the opportunities of multinationals to shift income outside high‐tax jurisdictions. Finally, the paper shows that profit shifting largely takes place into tax havens, whereas other countries do not benefit from profit‐shifting activities. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of the water/cement ratio on concrete behavior under extreme loading
Authors: Vu Xuan Hong , Malecot Yann , Daudeville Laurent , Buzaud Eric 
Published: April 2009

AbstractThis study focuses on identifying concrete behavior under severe triaxial loadings (near field detonation or ballistic impacts). In order to reproduce high stress levels with well‐controlled loading paths, static tests have been carried out on concrete samples by mean of a very high‐capacity triaxial press (stress levels on the order of 1 GPa). It is a longstanding fact that the water/cement ratio (W/C), upon entering the concrete composition, is a major parameter affecting the porosity and strength of the cement matrix of hardened concrete. The objective of this article is to quantify the effect of this ratio on concrete behavior under conditions of high confinement. From the composition of a reference ‘ordinary’ concrete (i.e. W/C=0.6), two other concretes have been produced with W/C ratios equal to 0.4 and 0.8, respectively. This article presents experimental results and their analysis regarding the effect of water/cement ratio (W/C) on concrete behavior under high confinement. It shows that when placed under high confinement, concrete behaves like a granular stacking composed of concrete without any influence from the level of cement matrix strength. Copyright © 2009 John Wiley & Sons, Ltd.
Quantification of J‐resolved proton spectra in two‐dimensions with LCModel using GAMMA‐simulated basis sets at 4 Tesla
Authors: Jensen J. Eric , Licata Stephanie C. , Öngür Dost , Friedman Seth D. , Prescot Andrew P. , Henry Michael E. , Renshaw Perry F. 
Published: April 2009

AbstractA two‐dimensional, J‐resolved magnetic resonance spectroscopic extraction approach was developed employing GAMMA‐simulated, LCModel basis‐sets. In this approach, a two‐dimensional J‐resolved (2D‐JPRESS) dataset was resolved into a series of one‐dimensional spectra where each spectrum was modeled and fitted with its theoretically customized LCModel template. Metabolite levels were derived from the total integral across the J‐series of spectra for each metabolite. Phantoms containing physiologic concentrations of the major brain chemicals were used for validation. Varying concentrations of glutamate and glutamine were evaluated at and around their accepted in vivo concentrations in order to compare the accuracy and precision of our method with 30 ms PRESS. We also assessed 2D‐JPRESS and 30 ms PRESS in vivo, in a single voxel within the parieto‐occipital cortex by scanning ten healthy volunteers once and a single healthy volunteer over nine repeated measures. Phantom studies demonstrated that serial fitting of 2D‐JPRESS spectra with simulated LCModel basis sets provided accurate concentration estimates for common metabolites including glutamate and glutamine. Our in vivo results using 2D‐JPRESS suggested superior reproducibility in measuring glutamine and glutamate relative to 30 ms PRESS. These novel methods have clear implications for clinical and research studies seeking to understand neurochemical dysfunction. Copyright © 2009 John Wiley & Sons, Ltd.
On the assessment of cerebrovascular reactivity using hypercapnia BOLD MRI
Authors: Yezhuvath Uma S. , Lewis‐Amezcua Kelly , Varghese Rani , Xiao Guanghua , Lu Hanzhang 
Published: April 2009

AbstractCerebrovascular reactivity (CVR) reflects the capacity of blood vessels to dilate and is an important marker for brain vascular reserve. It may provide a useful addition to the traditional baseline blood flow measurement when assessing vascular factors in brain disorders. Blood‐oxygenation‐level‐dependent MRI under CO2 inhalation offers a non‐invasive and quantitative means to estimate CVR in humans. In this study, we investigated several important methodological aspects of this technique with the goal of optimizing the experimental and data processing strategies for clinical use. Comparing 4 min of 5% CO2 inhalation (less comfortable) to a 1 min inhalation (more comfortable) duration, it was found that the CVR values were 0.31 ± 0.05%/mmHg (N = 11) and 0.31 ± 0.08%/mmHg (N = 9), respectively, showing no significant differences between the two breathing paradigms. Therefore, the 1 min paradigm is recommended for future application studies for patient comfort and tolerability. Furthermore, we have found that end‐tidal CO2 recording was useful for accurate quantification of CVR because it provided both timing and amplitude information regarding the input function to the brain vascular system, which can be subject‐dependent. Finally, we show that inter‐subject variations in CVR are of physiologic origin and affect the whole brain in a similar fashion. Based on this, it is proposed that relative CVR (normalized against the CVR of the whole brain or a reference tissue) may be a more sensitive biomarker than absolute CVR in clinical applications as it minimizes inter‐subject variations. With these technological optimizations, CVR mapping may become a useful method for studies of neurological and psychiatric diseases. Copyright © 2009 John Wiley & Sons, Ltd.
Template‐free microsphere and hollow sphere formation of polymethylanilines
Authors: İçli Merve , Önal Ahmet M , Cihaner Atilla 
Published: April 2009

AbstractBACKGROUND: Microsphere and/or hollow sphere formation of methyl‐substituted polyaniline derivatives was investigated via chemical polymerization where different sets of conditions were examined. It was found that a variety of parameters (e.g. types and concentrations of monomer and oxidant, polymerization time, solvent with and without acid) have a crucial influence on the morphology of the resulting polyaniline derivatives.RESULTS: Structures with desired morphologies (with or without microspheres and hollow spheres) may be obtained in a controlled manner by changing the parameters. Moreover, the electrochemical and optical properties of the polymers in the presence of acid and/or base were investigated via cyclic voltammetry and UV‐visible and electron spin resonance spectroscopic techniques. It is noteworthy that the morphologies of microspheres and/or hollow spheres remained unchanged after repeated acid and base treatments.CONCLUSION: Micro/hollow spherical structures were successfully prepared via chemical polymerization of various substituted anilines by using ammonium persulfate as oxidant. It was found that the type of oxidant and monomers along with the polymerization time are quite important factors for the formation of micro/hollow spheres. Furthermore, hydrogen bond formation does not play any crucial role for the formation of these spheres. Chemically and electrochemically doped/dedoped states of microspheres and/or hollow spheres are very sensitive, and give rapid response towards vapours of HCl and NH3, which makes them amenable for use in sensors. Copyright © 2009 Society of Chemical Industry
Solar‐tracking PV plants in Navarra: A 10 MW assessment
Authors: García Miguel , Vera Jose A. , Marroyo Luis , Lorenzo Eduardo , Pérez Miguel 
Published: April 2009

AbstractCurrently, the know‐how and experience concerning the behavior and reliability of large tracking photovoltaic (PV) plants is scarce. Information such as the availability rate is rarely known. Acciona Solar PV plants installed in Navarra (Spain) in the frame of the Spanish utility grid constitute a representative source of information. The scope of this study is to analyze in detail the behavior along 2006 of six of these plants, located in Arguedas (two plants of a rated nominal power of 940 kWp and 2·1 MWp, respectively), Sesma (1·12 MWp), Cintruénigo (1·44 MWp), Rada (1·78 MWp), and Castejón (2·64 MWp). In our analysis, the influence of each type of energy loss affecting the plants has been quantified; and the advantages of dedicating human resources to the surveillance and maintenance of a limited number of generators have been stated. Thanks to the work of the operators, the plants registered mean availability rates above 99·7%. Copyright © 2009 John Wiley & Sons, Ltd.
Embryonic stem cells derived from somatic cloned and fertilized blastocysts are post‐transcriptionally indistinguishable: A MicroRNA and protein profile comparison
Authors: Ding Junjun , Guo Yuanbiao , Liu Sheng , Yan Yujuan , Chang Gang , Kou Zhaohui , Zhang Yu , Jiang Ying , He Fuchu , Gao Shaorong , Sang Jianli 
Published: April 2009

AbstractTherapeutic cloning, whereby somatic cell nuclear transfer is used to generate customized embryonic stem cells (NT‐ES) from differentiated somatic cells of specific individuals, has been successfully performed in mice and non‐human primates. Safety concerns have prevented this technology from being potentially applied to humans, as severely abnormal phenotypes have been observed in cloned animals. Although it has been demonstrated that the transcriptional profiles and developmental potentials of ES cells derived from cloned blastocysts are identical to those of ES cells derived from fertilized blastocysts (F‐ES), a systematic analysis of the post‐transcriptional profiles of NT‐ES cell lines has not yet been performed. To investigate whether NT‐ES cells are comparable to F‐ES cells post‐transcriptionally, we compared the microRNA and protein profiles of five NT‐ and matching F‐ES cell lines by microRNA microarray, 2‐D DIGE and bioinformatic analyses. Stem‐loop real‐time PCR and MS/MS assays were further performed to verify the expression of specific microRNAs and characterize differentially expressed proteins. Our results demonstrate that the ES cell lines derived from cloned and fertilized mouse blastocysts have highly similar microRNA and protein expression profiles, consistent with their similar developmental potentials and transcriptional profiles.