bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurements of electron temperature and ion density in an ac pulsed CO plasma study
Authors: Martinez H. , Castillo F. 
Published: March 2008

AbstractEmission spectroscopy was applied to observe CO plasma, which was generated by AC discharge at the pressure range between 0.2 to 0.9 Torr. Electron temperature and ion density measurements were performed using a double Langmuir probe. Measured electron temperature was found to be inversely proportional to pressure, while ion density shows increasing behavior as a function of discharge pressure. Within the plasma conditions under consideration, O2, O2+, O, C2, C2–, CO and CO+ play a dominant role in the pulsed plasma process within the spectral range of (200‐800 nm), and the importance of these components vary little under the conditions of the plasma studied in this work. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma immersion ion implantation with auxiliary heating: application to SS304 stainless steel
Authors: Ueda M. , Geraldo A. S. , Mello C. B. , Lepienski C. M. 
Published: March 2008

AbstractIn the present experiment, we heated the sample holding fixture using a shielded resistive wire wound around it and the SS samples were subjected to nitrogen glow discharge plasma PIII with moderate voltages of 10 kV, in different temperatures (250 °C, 270 °C, 350 °C and 390 °C). Then, we compared them to the samples obtained by PIII in which the final temperature of 350 °C was reached, solely by the bombardment of accelerated ions. X‐ray diffraction results indicated a much higher efficiency of auxiliary heated PIII mode com‐ pared to the ordinary PIII. Very prominent γN peaks were observed for the first mode, indicating large concentration of nitrogen in thick layers, confirmed by the nitrogen profiles measured by GDOS technique. Improved mechanical and tribological properties were obtained for SS304 samples treated by the PIII with auxiliary heating, more than for ordinary PIII. Corrosion resistance of treated samples was maintained or it was slightly lower compared to the reference sample. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel process for plasma immersion ion implantation and deposition with ions from vaporization of solid targets
Authors: Oliveira R. M. , Ueda M. , Moreno B. , Hoshida L. , Oswald S. , Abramof E. 
Published: March 2008

AbstractA novel source for plasma immersion ion implantation and deposition (PIII&D) was developed in order to perform surface treatment of materials with ions from vaporization of solid targets. Usually this is obtained by means of beamline ion implanters, in which three dimensional implantation requires target manipulation, or by vacuum arc discharges, in which the presence of macroparticles is the main problem to be overcame. Samples of silicon wafers immersed in a lithium plasma produced by this source were submitted to low negative high frequency pulses (3‐4 kV/6 μs/3 kHz), causing lithium implantation and deposition. A very high strain and photoluminescence measured by high resolution X‐ray diffraction and Raman spectroscopy, respectively, were observed in the analyzed layers of the samples that were immersed in this plasma. XPS measurements revealed thick Li deposition for samples treated under conditions of high lithium vaporization rate. This novel process was effective for Li implantation/deposition and shows potential for PIII or PIII&D of many different elements from solid targets as Ca, K, Mg and Al. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of Ag and PE interface after plasma treatment
Authors: Mackova A. , Malinsky P. , Bocan J. , Svorcik V. , Pavlik J. , Stryhal Z. , Sajdl P. 
Published: March 2008

AbstractIn this study, the effect of simultaneous plasma treatment and thermal annealing on the diffusion of Ag in low and high‐density polyethylene (LDPE and HDPE) and on intermixing at the metal/polymer interface is examined. Metal layers were deposited onto 50 μm thick LDPE and HDPE foils using diode sputtering. Concentration profiles of Ag were determined by Rutherford back‐scattering spectrometry (RBS). Ag diffusion coefficients in LDPE and HDPE were extracted from measured Ag depth profiles. Diffusion coefficients 5.05×10–14– 6.78×10–14 cm2.s–1 and 2.44×10–14–4.66×10–14 cm2.s–1 were found for Ag in HDPE and Ag in LDPE, respectively. Morphology changes after the plasma treatment were determined using atomic force microscopy (AFM) and from RBS measurements as well. Surface fraction of Ag and plasma induced surface chemistry modification was investigated using XPS analysis. The signal of Ag bonded on polymer structure was identified and degradation of polymer substrate was observed in XPS spectra. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deposition and characterization of copper thin films on a polymer surface by using a dc cylindrical magnetron sputtering technique
Authors: Tyagi V. , Ranjan M. , Rane R. , Vaghela N. , Barhai P.K. , Acharya V. , Mukherjee S. 
Published: March 2008

AbstractIn the present study copper thin films were deposited on a polymer surface at room temperature using a specially developed DC cylindrical magnetron sputtering technique. The polymer chosen is light weight with a smooth surface. To have strongly adherent copper films, the polymer surface was initially etched for 2 hours by using an argon glow discharge created by a bi‐polar pulse power supply. After the etching treatment the water contact angle decreased from 75° to 9°. A dc cylindrical post magnetron, made from copper, was specially developed for depositing copper on the etched surface. The magnetron was biased to ‐800 V with typical discharge currents ∼ 200 mA. An axial magnetic field of 100 Gauss was applied to have EXB rotation of electrons. Argon was the sputtering gas during deposition at a pressure of 0.015 mbar. The sputtered copper was deposited on the etched polymer for 8 hours giving a film thickness of ∼12 μm. X‐ray diffraction studies showed the formation of polycrystalline copper film with sub‐100 nm crystallite sizes. Scanning electron microscopy showed the surface morphology. The cylindrical post magnetron was developed as it gave reduced deposition rate, and lower amount of stresses made the film strongly boned to the polymer surface. The article highlights the development of the cylindrical post magnetron and its use as a reliable coating device on various surfaces. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biocompatible DLC coatings by PBII: Effects of doping and surface roughness
Authors: Wehlus T. , Thorwarth G. , Schwarz F. , Schneider M. F. , Saldamli B. , Stritzker B. 
Published: March 2008

AbstractDue to its excellent mechanical and bio‐inert characteristics, diamond‐like carbon (DLC, a‐C:H) has been established as a favored coating material especially for loadbearing implants. The addition of dopants into the DLC matrix opens further possibilities to tune the layer properties to the body environment. We present results on the effects of various dopants (N, Si, halogenes), surface roughness and surface activation treatment on the surface energy and cellular adhesion. Sample coatings were prepared on TiAlV substrates by PBII and simultaneous condensation of hydrocarbons and the respective dopant precursor gases. The layers' composition was assessed by ion beam analysis (RBS, ERDA). The investigations indicate a wide range of accessible DLC characteristics by PBII and thus the feasibility of optimized wear‐resistant coatings by this method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of droplet‐free metal ion source to formation of gas barrier thin films
Authors: Nakamura K. 
Published: March 2008

AbstractThis paper reports on application of droplet‐free aluminum ion sources for formation of gas barrier coating of PTFE polymer sheets. Addition of oxygen to the ion source was also made in order to obtain transparent coating films of alumina. Optimized conditions on the oxygen addition allowed the transparent almina films to be formed without a significant decrease in deposition rate. Square‐wave‐modulated bias voltages were also applied to the sheet with the film in order to control the incident ion bombarding energy, and was much effective for improvement of gas barrier performance. However such a bias effect was obtained only under a discharge condition that the aluminum ions were efficiently produced. The alumina films had less bias effect than the aluminum films. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid analysis of α‐dicarbonyl compounds by laser desorption/ionization mass spectrometry using 9‐(3,4‐diaminophenyl)acridine (DAA) as a reactive matrix
Authors: Mugo Samuel M. , Bottaro Christina S. 
Published: March 2008

AbstractA rapid, sensitive and selective method has been developed for the analysis of α‐dicarbonyls using a readily ionizable compound, 9‐(3,4‐diaminophenyl)acridine (DAA), as a reactive matrix (derivatizing agent and ionization efficiency enhancer), by reactive matrix laser desorption/ionization time‐of‐flight mass spectrometry (RM‐LDI‐TOF MS). The reaction between the DAA and α‐dicarbonyls resulted exclusively in formation of vacuum‐stable dicarbonyl‐quinoxaline acridine derivatives that were found to possess excellent ionization efficiency in positive ion mode, without the need to use an additional matrix. The α‐dicarbonyls used as test compounds included methylglyoxal, dimethylglyoxal, and diphenylglyoxal. Both one‐pot and rapid on‐plate chemical modification approaches were employed with no extraction or purification necessary. The approach is particularly suitable for high‐throughput analysis. The method was found to be selective and specific, with α‐dicarbonyls unequivocally identified, even in complex matrices, e.g. beer. The figures of merit: relative standard deviation (RSD) 6.9–17%, (n = 4); limit of detection (LOD) ≤0.3 ng mL−1 for the three standards tested using the one‐pot derivatization method; and a good linear calibration curve using an internal standard derivatized in situ (R2 ≥ 0.979), demonstrate the applicability of the technique and its utility in improving the sensitivity and precision of the LDI analysis of small molecules. Copyright © 2008 John Wiley & Sons, Ltd.
Highly efficient enrichment of phosphopeptides by magnetic nanoparticles coated with zirconium phosphonate for phosphoproteome analysis
Authors: Wei Junying , Zhang Yangjun , Wang Jinglan , Tan Feng , Liu Jinfeng , Cai Yun , Qian Xiaohong 
Published: March 2008

AbstractThe location of phosphorylation plays a vital role for the elucidation of biological processes. The challenge of low stoichiometry of phosphoproteins and signal suppression of phosphopeptides by nonphosphopeptides in mass spectrometry (MS) analysis makes the selective enrichment of phosphopeptides prior to MS analysis necessary. Besides the immobilized metal affinity chromatography (IMAC) method, some affinity methods based on nanoparticles displayed a higher enrichment efficiency for phosphopeptides such as Fe3O4/TiO2 and Fe3O4/ZrO2 nanoparticles. To further improve the selectivity and compatibility of the affinity methods, a novel strategy based on magnetic nanoparticles coated with zirconium phosphonate for the enrichment of phosphopeptides has been developed in this study. Under optimized experimental conditions, 1 × 10−9 M phosphopeptides in 50 µL tryptic digest of β‐casein could be enriched and identified successfully. Reliable results were also obtained for 1 × 10−8 M phosphopeptides in 50 µL tryptic digest of β‐casein in the presence of nonphosphopeptides from a tryptic digest of bovine serum albumin (BSA) over 20 times in concentration. The performance of nanoparticles for use in a real sample was further demonstrated by employing the strong cation‐exchange chromatography (SCX) fraction of a tryptic digest of a protein extract from Chang liver cells as a model sample. Experimental results show that the nanoparticles can be easily and effectively used for enrichment of phosphopeptides in low concentration. Most importantly, our approach is more compatible with commonly used SCX strategies than Fe3+‐IMAC. The proposed method thus has great potential for future studies of large‐scale phosphoproteomes. Copyright © 2008 John Wiley & Sons, Ltd.
Theoretical study of vacuum level shift at the C6H6/Al(111) interface
Authors: Nakano Yosuke , Yanagisawa Susumu , Hamada Ikutaro , Morikawa Yoshitada 
Published: March 2008

AbstractWe have investigated the interface dipole induced at C6H6/Al(111) by using density functional theory (DFT) within the generalized gradient approximation (GGA). We calculated the vacuum level shift from a simple induced density of interface state (IDIS) model and compared it with that estimated by self‐consistent DFT‐GGA calculations. Both results agree reasonably well with each other in weakly interacting cases, where the charge donation from the highest occupied molecular orbital level dominates, while they deviate from each other in strongly interacting cases, where the lowest unoccupied molecular orbital level starts to be partially filled owing to the back donation from the substrate. Even in weakly interacting cases, the actual charge density distribution is more complex than that assumed in the IDIS model. We discuss the validity and the limitations of the IDIS model to describe the vacuum level shift at organic/metal interfaces. Copyright © 2008 John Wiley & Sons, Ltd.
Path‐integral renormalization group treatments for many‐electron systems with long‐range repulsive interactions
Authors: Kojo Masashi , Hirose Kikuji 
Published: March 2008

AbstractWe derive a practical algorithm to study many‐electron systems based on the path‐integral renormalization group (PIRG) method within the framework of the real‐space finite‐difference (RSFD) approach. The PIRG method, originally developed for investigating strongly correlated electron systems, has been successfully applied to some models such as Hubbard models. However, to apply this method to more realistic systems of electrons with long‐range Coulomb interactions in the RSFD approach, the one‐body Green's function, which requires large computational resources, must be removed. For the same reason, an efficient algorithm for computing the Fock matrix is needed. The newly proposed algorithm is free of the one‐body Green's function and enables us to compute the Fock matrix efficiently. Our result shows a significant reduction in CPU time and the possibility of using the present algorithm as a practical numerical tool. Copyright © 2008 John Wiley & Sons, Ltd.
Role of aldosterone in stress‐induced antinatriuresis in normotensive saline overload rats
Authors: Niebylski Ana , Bensi Nora , Gauna Héctor Fernando 
Published: March 2008

AbstractThe aim of this study was to determine aldosterone participation in the stress‐induced antinatriuresis in normotensive saline overload rats, as a probable cause of stress‐induced hypertension. Spironolactone (Sp) 6 mg/kg/day, intraperitoneal injection, as a Mineralocorticoid receptor antagonist was used. The rats were divided into four groups: basal (B), basal drug (B‐Sp), stress [Immobilization stress (IMO)] and stress‐Sp (IMO‐Sp). Urinary Na+ and K+ were measured and the K+/Na+ ratio was calculated. Aldosterone and corticosterone plasmatic levels were determined. Stressed rats showed higher aldosterone and corticosterone levels than the ones in the basal group. The antinatriuretic effect in response to acute IMO was not reverted with Sp. However, IMO‐Sp animals showed higher urinary sodium levels than IMO animals suggesting a partial inhibition of the stress response. The IMO‐Sp animals excreted 50 per cent of basal sodium while IMO animals excreted about 20 per cent of B sodium. This effect was also evidenced in the urinary K+/Na+ ratio. In conclusion, aldosterone would be a factor influencing sodium reabsorption in stressed rats. Since sodium distal handling is small with respect the proximal ones, in which the sympathetic innervation is great, the inhibition of aldosterone action is not enough to revert antinatriuretic effect. Besides, the high levels of corticosterone might exert some effect on stress‐induced antinatriuresis. These results show the importance of aldosterone in the sodium reabsorption in IMO rats as a contributing factor to explain the origin of stress‐induced hypertension in rats. Copyright © 2008 John Wiley & Sons, Ltd.
Psychological distress in chronic obstructive pulmonary disease patients
Authors: Karadag Fisun , Ozcan Hatice , Eskin Mehmet , Karul Aslihan B. , Ceylan Emel , Tufek Yasemin , Cildag Orhan 
Published: March 2008

AbstractStress is defined as the exposure of an individual to a threatening stimulus or overwhelming event. Increased rates of psychological distress have been established in patients with chronic diseases compared to healthy individuals. The objective of the present study is to assess the indicators and correlates of psychological distress in chronic obstructive pulmonary disease (COPD) patients.We evaluated the stress exposure (stressful events that COPD patients and control subjects had been exposed) by a life events checklist and psychological distress by General Health Questionnaire in 74 COPD patients and 30 control subjects. Serum adrenocorticotropic hormone (ACTH) and cortisol levels were measured as biochemical indicators of stress.Distress score was higher in COPD group compared to age‐matched controls, although the stress exposure score were not statistically different; indicating that COPD itself is a source of distress. 92% of COPD patients and 87% of control subjects had varying degrees of distress. Severe distress was more frequent in COPD group. Distress score was further increased in patients with severe COPD and severe hypoxemia.There was no significant difference in serum ACTH and cortisol levels of COPD patients and control subjects and distress scores were not correlated to serum ACTH and cortisol levels. However, serum cortisol was higher in patients with severe hypoxemia.These findings support the importance of screening for psychological distress symptoms in COPD outpatients. Since high degree of distress contributes to impaired quality of life and added morbidity, patients with COPD need a comprehensive care including a psychological evaluation. Copyright © 2008 John Wiley & Sons, Ltd.
Die Brücke über den Oberhafen in Hamburg
Authors: Dieckmann Christof , Hagedorn Michael , Heiland Uwe , Weyer Ulrich 
Published: March 2008

AbstractDer Ersatzneubau von vier stählernen Eisenbahnbrücken mit einer Tonnage von ca. 4000 t Konstruktionsstahl im Stadtzentrum Hamburgs, mit denen der Hamburger Hauptbahnhof aus südlicher Richtung erschlossen wird, definierte eine anspruchsvolle Bauaufgabe.Der zentrale Stahlüberbau dieses Brückenzuges, die Oberhafenbrücke, ein 5‐feldriger Fachwerkdurchlaufträger, hat dabei die Besonderheit, als kombinierte Eisenbahn‐ und Straßenbrücke ausgelegt zu sein. Dieser Überbau überführt die Eisenbahnverbindung über den Oberhafenkanal. Dabei nimmt die Obergurtebene des Fachwerkes den Eisenbahnverkehr auf. Der Fahrbahnplatte für den Straßenverkehr ist im Untergurtbereich (zwischen den Fachwerkwänden) angeordnet.Für alle Prozesse der Bauausführung mit Statik, Planung, Fertigung und Montage des Brückenzuges standen 14 Monate Bauzeit zur Verfügung.Das Bauende war bestimmt durch eine langfristig vorgegebene Sperrung der betroffenen Bahnverbindung und Teil en des Hamburger Hauptbahnhofes in der Zeit vom 24. bis 31. Dezember 2007.Trotz der Neudefinition wesentlicher Entwurfparameter (Belastungsmodelle Straße und Bahn, Lagerschemata, Hilfslagerung ab dem 31. 12. 2007) und damit einer um ca. vier Monate verkürzten Ausführungszeit, wurde die Bauaufgabe durch eine ARGE bestehend aus den Firmen Eiffel Deutschland Stahltechnologie GmbH, Bilfinger Berger AG ZN Hamburg, Jürgen Martens GmbH & Co. KG Hamburg erfolgreich gelöst.
Netzwerkbogenbrücken – Entwurf, Bemessung, Ausführung
Authors: Geißler Karsten , Steimann Uwe , Graße Wolfgang 
Published: March 2008

AbstractDie Bauweise des Netzwerkbogens als fachwerkartig ausgesteifte Stabbogenbrücke erfreut sich im deutschen Brückenbau einer steigenden Akzeptanz. Sie kombiniert die Vorteile des Bogens mit denen des Fachwerks. Die möglichen schlanken Querschnitte von Bogen und Untergurt führen in Verbindung mit dem kaum wahrzunehmenden Hängernetz zu einem äußerst transparenten Tragwerk mit geringer Beeinflussung des städtebaulichen Umfeldes oder der Landschaft. Mit dem Netzwerkbogen sind auch größere Stützweiten von bis zu 300 m möglich.Im Folgenden werden die Grundlagen zum Entwurf der Tragkonstruktion beschrieben und anhand von geplanten sowie teilweise bereits ausgeführten Bauwerken der aktuelle Stand in der Konstruktion und Bemessung von Netzwerkbögen erläutert.
Conjugated Linoleic Acids and CLA‐Containing Phospholipids Inhibit NO Formation in Aortic Endothelial Cells
Authors: Jenko Kimberly J. , Vanderhoek Jack Y. 
Published: March 2008

AbstractThis study examined the effects of five CLA isomers and the non‐conjugated LA on nitric oxide (NO) production, an important modulator of vasodilation, inflammation, and cytotoxicity. Bovine aortic endothelial cells (BAECs) were pretreated with pure CLAs (c9, c11‐, c9, t11‐, t9, t11‐, t10, c12‐, c11, c13‐CLA) and the non‐conjugated c9, c12‐analog, then stimulated by the ionophore A23187 followed by fluorescence monitoring of NO production. CLAs (5 μM) decreased NO formation in the range of 20–40% relative to non‐fatty acid‐treated controls with the t9, t11‐ and t10, c12‐CLAs being the most effective. The inhibitory effect of either of these CLAs was not time dependent over a 120 min time interval. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) play crucial roles in membrane structure and cell signaling. Since CLAs are usually esterified in these phospholipids (PLs), the effects of three CLA‐containing PLs and 2‐linoleoyl‐PC on NO production by A23187‐stimulated BAECs were also examined. c9, t11‐CLA‐PC and 2‐linoleoyl‐PC dose‐dependently inhibited NO production over a 60–1,000 μM concentration range whereas c9, c11‐CLA‐PC and c9, t11‐CLA‐PE were ineffective. Both c9, t11‐CLA‐PC and linoleoyl‐PC exhibited a time‐dependent decrease in NO production from 5 to 120 min. The results of the present study suggest that the influence of several C18 polyunsaturated fatty acids incorporated into cellular phospholipids on the A23187‐induced formation of NO by BAECs is strongly dependent on the positional and geometric nature of the double bonds.
Inhibition of Serum Cholesterol Oxidation by Dietary Vitamin C and Selenium Intake in High Fat Fed Rats
Authors: Menéndez‐Carreño M. , Ansorena D. , Milagro F. I. , Campión J. , Martínez J. A. , Astiasarán I. 
Published: March 2008

AbstractCholesterol oxidation products (COPs) have been considered as specific in vivo markers of oxidative stress. In this study, an increased oxidative status was induced in Wistar rats by feeding them a high‐fat diet (cafeteria diet). Another group of animals received the same diet supplemented with a combination of two different antioxidants, ascorbic acid (100 mg/kg rat/day) and sodium selenite (200 μg/kg rat/day) and a third group fed on a control diet. Total and individual COPs analysis of the different diets showed no differences among them. At the end of the experimental trial, rats were sacrificed and serum cholesterol, triglycerides and COPs were measured. None of the diets induced changes in rats body weight, total cholesterol and triglycerides levels. Serum total COPs in rats fed on the high‐fat diet were 1.01 μg/ml, two times the amount of the control rats (0.47 μg/ml). When dietary antioxidant supplementation was given, serum total COPs concentration (0.44 μg/ml) showed the same levels than those of the rats on control diet. 7β‐hydroxycholesterol, formed non‐enzymatically via cholesterol peroxidation in the presence of reactive oxygen species, showed slightly lower values in the antioxidant‐supplemented animals compared to the control ones. This study confirms the importance of dietary antioxidants as protective factors against the formation of oxysterols.