bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization and modelling techniques for gas metal arc welding of DP 600 sheet steels
Authors: Mukherjee K. , Prahl U. , Bleck W. , Reisgen U. , Schleser M. , Abdurakhmanov A. 
Published: November 2010

AbstractThe objectives of the present work are to characterize the Gas Metal Arc Welding process of DP 600 sheet steel and to summarize the modelling techniques. The time‐temperature evolution during the welding cycle was measured experimentally and modelled with the softwaretool SimWeld. To model the phase transformations during the welding cycle dilatometer tests were done to quantify the parameters for phase field modelling by MICRESS®. The important input parameters are interface mobility, nucleation density, etc. A contribution was made to include austenite to bainite transformation in MICRESS®. This is useful to predict the microstructure in the fast cooling segments. The phase transformation model is capable to predict the microstructure along the heating and cooling cycles of welding. Tensile tests have shown the evidence of failure at the heat affected zone, which has the ferrite‐tempered martensite microstructure.Die Ziele der gegenwärtigen Arbeit sind, das Verfahren des Metallschutzgasschweißens von DP 600 Blech‐Stahl zu charakterisieren und die entsprechenden Modellierungstechniken zusammenzufassen. Der Zeit‐Temperaturverlauf während des Schweißzyklus wurde experimentell gemessen und anhand der Simulationssoftware SimWeld modelliert. Um die Phasenumwandlungen während des Schweißzyklus zu modellieren wurden Dilatometrie‐Versuche, für die Quantifizierung der Parameter für die Phasenfeldmodellierung durch MICRESS®, durchgeführt. Die wichtigsten Eingangsparameter sind Grenzschichtmobilität, Keimbildungsdichte etc. Es wurde eine Methode entwickelt, mit der die Transformation von Austenit zu Bainit in MICRESS® überführt werden kann. Dies ist nützlich, um die Mikrostruktur in den schnell abkühlenden Bereichen vorauszusagen. Das Phasenumwandlungsmodell ist in der Lage, die Mikrostruktur entlang der Aufheiz‐ und Abkühlungszyklen des Schweißens abzuschätzen. Zugversuche haben gezeigt, dass das Versagen in der Wärmeeinflusszone, die aus einer ferritisch‐gehärteten martensitischen Mikrostruktur besteht, stattfindet.
Mapping proteoglycan‐bound water in cartilage: Improved specificity of matrix assessment using multiexponential transverse relaxation analysis
Authors: Reiter David A. , Roque Remigio A. , Lin Ping‐Chang , Irrechukwu Onyi , Doty Stephen , Longo Dan L. , Pleshko Nancy , Spencer Richard G. 
Published: November 2010

AbstractAssociation of MR parameters with cartilage matrix components remains an area of ongoing investigation. Multiexponential analysis of nonlocalized transverse relaxation data has previously been used to quantify water compartments associated with matrix macromolecules in cartilage. We extend this to mapping the proteoglycan (PG)‐bound water fraction in cartilage, using mature and young bovine nasal cartilage model systems, toward the goal of matrix component‐specific imaging. PG‐bound water fraction from mature and young bovine nasal cartilage was 0.31 ± 0.04 and 0.22 ± 0.06, respectively, in agreement with biochemically derived PG content and PG‐to‐water weight ratios. Fourier transform infrared imaging spectroscopic‐derived PG maps normalized by water content (IR‐PGww) showed spatial correspondence with PG‐bound water fraction maps. Extensive simulation analysis demonstrated that the accuracy and precision of our determination of PG‐bound water fraction was within 2%, which is well‐within the observed tissue differences. Our results demonstrate the feasibility of performing imaging‐based multiexponential analysis of transverse relaxation data to map PG in cartilage. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Statistical noise analysis in GRAPPA using a parametrized noncentral Chi approximation model
Authors: Aja‐Fernández Santiago , Tristán‐Vega Antonio , Hoge W. Scott 
Published: November 2010

AbstractThe characterization of the distribution of noise in the magnitude MR image is a very important problem within image processing algorithms. The Rician noise assumed in single‐coil acquisitions has been the keystone for signal‐to‐noise ratio estimation, image filtering, or diffusion tensor estimation for years. With the advent of parallel protocols such as sensitivity encoding or Generalized Autocalibrated Partially Parallel Acquisitions that allow accelerated acquisitions, this noise model no longer holds. Since Generalized Autocalibrated Partially Parallel Acquisitions reconstructions yield the combination of the squared signals recovered at each receiving coil, noncentral Chi statistics have been previously proposed to model the distribution of noise. However, we prove in this article that this is a weak model due to several artifacts in the acquisition scheme, mainly the correlation existing between the signals obtained at each coil. Alternatively, we propose to model such correlations with a reduction in the number of degrees of freedom of the signal, which translates in an equivalent nonaccelerated system with a minor number of independent receiving coils and, consequently, a lower signal‐to‐noise ratio. With this model, a noncentral Chi distribution can be assumed for all pixels in the image, whose effective number of coils and effective variance of noise can be explicitly computed in a closed form from the Generalized Autocalibrated Partially Parallel Acquisitions interpolation coefficients. Extensive experiments over both synthetic and in vivo data sets have been performed to show the goodness of fit of out model. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Contrast‐enhanced whole‐heart coronary MRI with bolus infusion of gadobenate dimeglumine at 1.5 T
Authors: Hu Peng , Chan Jonathan , Ngo Long H. , Smink Jouke , Goddu Beth , Kissinger Kraig V. , Goepfert Lois , Hauser Thomas H. , Rofsky Neil M. , Manning Warren J. , Nezafat Reza 
Published: November 2010

AbstractWe sought to investigate the T1 kinetics of blood and myocardium after three infusion schemes of gadobenate dimeglumine (Gd‐BOPTA) and subsequently compared contrast‐enhanced whole‐heart coronary MRI after a bolus Gd‐BOPTA infusion with nonenhanced coronary MRI at 1.5 T. Blood and myocardium T1 was measured in seven healthy adults, after each underwent three Gd‐BOPTA infusion schemes (bolus: 0.2 mmol/kg at 2 mL/sec, hybrid: 0.1 mmol/kg at 2 mL/sec followed by 0.1 mmol/kg at 0.1 mL/sec, and slow: 0.2 mmol/kg at 0.3 mL/sec). Fourteen additional subjects underwent contrast‐enhanced coronary MRI with an inversion‐recovery steady‐state free precession sequence after bolus Gd‐BOPTA infusion. Images were compared with nonenhanced T2‐prepared steady‐state free precision whole‐heart coronary MRI in signal‐to‐noise ratio, contrast‐to‐noise ratio, depicted vessel length, vessel sharpness, and subjective image quality. Bolus and slow infusion schemes resulted in similar T1 during coronary MRI, whereas the hybrid infusion method yielded higher T1 values. A bolus infusion of Gd‐BOPTA significantly improved signal‐to‐noise ratio, contrast‐to‐noise ratio, depicted coronary artery length, and subjective image quality, when all segments were collectively compared but not when compared segment by segment. In conclusion, whole‐heart steady‐state free precision coronary MRI at 1.5 T can benefit from a bolus infusion of 0.2 mmol/kg Gd‐BOPTA. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Simple analytical dual‐band spectral‐spatial RF pulses for B1+ and susceptibility artifact reduction in gradient echo MRI
Authors: Yang Cungeng , Deng Weiran , Stenger V. Andrew 
Published: November 2010

AbstractSusceptibility artifacts and transmission radio frequency (RF) field (B1+) inhomogeneity are major limitations in high‐field gradient echo MRI. Previously proposed numerical 2D spectral‐spatial RF pulses have been shown to be promising for reducing the through‐plane signal loss susceptibility artifact by incorporating a frequency‐dependent through‐plane phase correction. This method has recently been extended to 4D spectral‐spatial RF pulse designs for reducing B1+ inhomogeneity as well as the signal loss. In this manuscript, we present simple analytical pulse designs for constructing 2D and 4D spectral‐spatial RF pulses as an alternative to the numerical approaches. The 2D pulse capable of exciting slices with reduced signal loss and is lipid suppressing. The 4D pulse simultaneously corrects signal loss as well as the B1+ inhomogeneity from a body coil transmitter. The pulses are demonstrated with simulations and with gradient echo phantom and brain images at 3T using a standard RF body coil. The pulses were observed to work well for multiple slices and several volunteers. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Wenig Gift — viel Kontakt
Authors: Sisnaiske Julia , Frimat Jean‐Philippe , Hengstler Jan G. , West Jonathan , van Thriel Christoph 
Published: November 2010

AbstractNervenzellen vernetzen sich miteinander — es sei denn, Neurotoxine stören sie dabei. Eine neue In‐vitro‐Methode ermittelt, wie schnell Zellfortsätze auf einer Analysenplattform wachsen, und misst so die Neurotoxizität von Chemikalien.
Vater der nuklearen und röntgenspektroskopischen Analytik
Authors: Niese Siegfried 
Published: November 2010

AbstractSeit dem Jahr 2007 erinnern die GDCh und die ungarische chemische Gesellschaft mit der Hevesy‐Vorlesung an den Naturforscher Georg von Hevesy. Der vor 125 Jahren in Budapest geborene Hevesy hatte ein bewegtes Leben: Politische Gründe zwangen ihn, Ungarn, Deutschland, Dänemark und die von ihm dort eingerichteten Laboratorien zu verlassen.
Daten sammeln und deuten
Authors: Kirsten Guido 
Published: November 2010

AbstractVerfahren wie das Hochdurchsatzscreening bringen dem Chemiker immer größere Datenmengen. Methoden wie Data Mining mit der Open‐Source‐Software Knime verwandeln die Datenflut in nützliche Informationen und geben Einblicke in Zusammenhänge, die beim sequenziellen Experimentieren kaum zugänglich sind.
Transaktionen im Aufwind
Authors: Schneider Bernd , Kuschel Matthias 
Published: November 2010

AbstractIm ersten Halbjahr gab es in der chemischen Industrie mehr Zusammenschlüsse und Übernahmen als im gleichen Zeitraum des Jahres zuvor. Deutsche, schweizerische und österreichische Unternehmen litten gleichermaßen unter der Krise.
Fehler beim Zement führten zur Katastrophe
Authors: Fischer Axel 
Published: November 2010

AbstractZeit‐ und Kostendruck verursachten die Ölkatastrophe im Golf von Mexiko: Eine falsche Zementmischung und ein schlampiger Einbau der Rohre im Bohrloch waren fatale Fehler, zu denen die BP‐Verantwortlichen auf der Bohrinsel Deepwater Horizon im Golf von Mexiko drängten.
Was riecht, wenn's gebrannt hat?
Authors: Heitmann Katharina , Wichmann Hubertus , Bahadir Müfit 
Published: November 2010

Abstract”Hier hat es gebrannt!“ Wer kennt nicht diesen typischen Geruch, der nach einem Feuer oder einem Schwelbrand noch lange in den betroffenen Zimmern und Fluren schwebt. Welche chemischen Verbindungen erzeugen diesen charakteristischen Geruch? GC/MS‐Analysen liefern die Antwort.
Ökonomie trifft Ökologie
Authors: Junk Christiane 
Published: November 2010

AbstractNach drei Jahren ist es wieder so weit: Die K 2010 findet vom 27. Oktober bis 3. November in Düsseldorf statt. Die Messe der Kunststoff‐ und Kautschukbranche zieht etwa 3000 internationale Aussteller an.
Aufbauen auf diesem Erfolg
Authors: Karger Gerhard 
Published: November 2010

Abstract2465 Chemiker und Chemikerinnen aus über 60 Ländern trafen sich vom 29. August bis 2. September in Nürnberg, um ihre Wissenschaft als kreative Kraft zu feiern. Der 3rd Euchems Chemistry Congress schreibt die Erfolgsgeschichte fort, die mit den Kongressen in Budapest und Turin begann.
Elegant und nützlich: Biomimetische Synthesestrategien
Authors: Kirsch Stefan , Harschneck Tobias 
Published: November 2010

AbstractEleganz und Schönheit, mit der die Natur ihre Naturstoffe aufbaut, dienen Chemikern seit langem als Inspiration. Um komplexe Strukturelemente einfach und schnell zugänglich zu machen, sind biomimetische Schlüsselschritte aus modernen Totalsynthesen nicht mehr wegzudenken.
Kuppler unter sich
Authors: Osterath Brigitte , Remenyi Christian 
Published: November 2010

AbstractDie Entwickler der palladiumkatalysierten C‐C‐Kupplungsmethoden galten stets als heiße Kandidaten für den Chemie‐Nobelpreis. Nun ist es endlich soweit: Richard F. Heck, Ei‐ichi Negishi und Akira Suzuki erhalten die Auszeichnung. Warum die Entscheidung des Nobelpreiskomitees längst überfällig war, und ob es die richtigen Kandidaten getroffen hat, fragten die Nachrichten aus der Chemie Matthias Beller vom Leibniz‐Institut für Katalyse in Rostock.
Increased blood oxygen level‐dependent (BOLD) sensitivity in the mouse somatosensory cortex during electrical forepaw stimulation using a cryogenic radiofrequency probe
Authors: Baltes Christof , Bosshard Simone , Mueggler Thomas , Ratering David , Rudin Markus 
Published: November 2010

AbstractFunctional MRI (fMRI) based on the blood oxygen level‐dependent (BOLD) contrast is widely used in preclinical neuroscience. The small dimensions of rodent brain place high demands on spatial resolution, and hence on the sensitivity of the fMRI experiment. This work investigates the performance of a 400‐MHz cryogenic quadrature transceive radiofrequency probe (CryoProbe) with respect to the enhancement of the BOLD sensitivity. For this purpose, BOLD fMRI experiments were performed in mice during electrical forepaw stimulation using the CryoProbe and a conventional room temperature surface coil of comparable dimensions. Image signal‐to‐noise ratio (SNR) and temporal SNR were evaluated as quality measures for individual images and for fMRI time series of images, resulting in gains (mean ± standard deviation) with factors of 3.1 ± 0.7 and 1.8 ± 1.0 when comparing the CryoProbe and room temperature coil. The CryoProbe thermal shield temperature did not affect the noise characteristics, with temporal noise levels being 63 ± 16% of the corresponding room temperature value. However, a significant effect on BOLD amplitudes was found, which was attributed to temperature‐dependent baseline cerebral blood volumes. Defined local thermal conditions were found to be a critical parameter for achieving an optimal and reproducible fMRI signal. In summary, the CryoProbe represents an attractive alternative for the enhancement of image SNR, temporal SNR and BOLD sensitivity in mouse fMRI experiments. Copyright © 2010 John Wiley & Sons, Ltd.
Changes in the metabolic profile of rat liver after α‐tocopherol deficiency as revealed by metabolomics analysis
Authors: Moazzami Ali A. , Andersson Roger , Kamal‐Eldin Afaf 
Published: November 2010

AbstractMetabolomics is an approach in which the profiles of metabolites in different tissues and/or biofluids are investigated to understand the changes induced following a modulation. We used this approach to investigate the biochemical effects of α‐tocopherol in the liver using a rat model. Rats (21‐day‐old) were fed either an α‐tocopherol‐sufficient control (n = 10) or an α‐tocopherol‐deficient (n = 10) diet for 2 months before sacrifice. Livers were homogenized in methanol–chloroform–water (3 : 1 : 1, v/v/v), and the polar phase extracts of the liver samples were analyzed using 1H NMR. Multivariate statistical analysis of the data was performed using principal component analysis and orthogonal partial least squares‐discriminant analysis. Identification of 1H NMR signals was performed primarily using the Human Metabolome Database, Biological Magnetic Resonance Data Bank and previous literature, and confirmed by spiking with metabolites and applying two‐dimensional NMR. The statistical analysis revealed that α‐tocopherol deficiency caused an increase in carnitine, choline, L‐valine, L‐lysine, tyrosine and inosine content and a reduction in glucose and uridine 5′‐monophosphate content. Changes in carnitine and glucose suggest a possible shift in energy metabolism. Copyright © 2010 John Wiley & Sons, Ltd.
Noninvasive quantification of human brain antioxidant concentrations after an intravenous bolus of vitamin C
Authors: Terpstra Melissa , Torkelson Carolyn , Emir Uzay , Hodges James S. , Raatz Susan 
Published: November 2010

AbstractUntil now, the lack of a means to detect a deficiency or to measure the pharmacologic effect in the human brain in situ has been a hindrance to the development of antioxidant‐based prevention and treatment of dementia. In this study, a recently developed 1H MRS approach was applied to quantify key human brain antioxidant concentrations throughout the course of an aggressive antioxidant‐based intervention. The concentrations of the two most abundant central nervous system chemical antioxidants, vitamin C and glutathione, were quantified noninvasively in the human occipital cortex prior to and throughout 24 h after bolus intravenous delivery of 3 g of vitamin C. Although the kinetics of the sodium‐dependent vitamin C transporter and physiologic blood vitamin C concentrations predict theoretically that brain vitamin C concentration will not increase above its homeostatically maintained level, this theory has never been tested experimentally in the living human brain. Therefore, human brain vitamin C and glutathione concentrations were quantified noninvasively using MEGA‐PRESS double‐edited 1H MRS and LCModel. Healthy subjects (age, 19–63 years) with typical dietary consumption, who did not take vitamin supplements, fasted overnight and then reported for the measurement of baseline antioxidant concentrations. They then began controlled feeding which they adhered to until after vitamin C and glutathione concentrations had been measured at 2, 6, 10 and 24 h after receiving intravenous vitamin C. Two of the twelve studies were sham controls in which no vitamin C was administered. The main finding was that human brain vitamin C and glutathione concentrations remained constant throughout the protocol, even though blood serum vitamin C concentrations spanned from the low end of the normal range to very high. Copyright © 2010 John Wiley & Sons, Ltd.
Studies of modification of HDPE and interfacial interaction of its composites with sericite
Authors: Li Shuya , Chen Qiang , Wu Shishan , Shen Jian 
Published: December 2010

AbstractUltraviolet irradiation, which is environment friendly and without any chemical pollution, was used to functionalize high‐density polyethylene (HDPE) and to improve the interfacial interaction of its composites with sericite in this study. The oxygen‐containing groups of CO, C‐O, and C(O)O were quickly introduced onto molecular chains of HDPE by ultraviolet irradiation in ozone atmosphere and the contents of the introduced oxygen‐containing groups increased with increasing the modification time. It is important to note that the irradiation time greatly decreased compared to that in air or oxygen atmosphere. After modification, the molecular weight of the irradiated HDPE decreased and its distribution became wider. The irradiated HDPE in ozone was not crosslinked, which is an advantage over the same reaction in air or oxygen atmosphere. With increasing the irradiation time, the melting temperature of the irradiated HDPE lightly decreased, while its crystallinity, hydrophilicity, and fluidity increased. The composites of HDPE/sericite were prepared. The results showed that the dispersion of sericite in the matrix and the interfacial interaction of sericite with the matrix were markedly improved for the irradiated HDPE/sericite composites. As a result, the irradiated HDPE/sericite composites showed significantly increased tensile yield strength and notched impact strength. Copyright © 2010 John Wiley & Sons, Ltd.
Preparation and properties of Nafion/SiO2 composite membrane derived via in situ sol–gel reaction: size controlling and size effects of SiO2 nano‐particles
Authors: Ke Chang‐Chun , Li Xiao‐Jin , Qu Shu‐Guo , Shao Zhi‐Gang , Yi Bao‐Lian 
Published: December 2010

AbstractA novel technique in controlling the size of SiO2 nano‐particles in the preparation of Nafion/SiO2 composite membranes via in situ sol–gel method, as well as the effects of nano‐particle size on membrane properties and cell performance, is reported in this paper. Nafion/SiO2 composite membranes containing SiO2 nano‐particles with four different diameters (5 ± 0.5, 7 ± 0.5, 10 ± 1, and 15 ± 2 nm) are fabricated by altering the reactant concentrations during in situ sol–gel reaction. Sequentially, size effects of SiO2 nano‐particles on membrane properties and cell performance are investigated by SEM/EDAX, TEM, TGA, mechanical tensile, and single cell tests, etc. The results suggest that 10 nm is a critical diameter for SiO2 incorporated into Nafion matrix, exhibiting desirable physico‐chemical properties for operation at elevated temperature and low humidity. At 110°C and 59% RH, the output voltage of the cell equipped with Nafion/SiO2 (10 nm) obtains an output voltage of 0.625 V at 600 mA/cm2, which is 50 mV higher than that of unmodified Nafion. Copyright © 2010 John Wiley & Sons, Ltd.
Helical opposition in poly(2‐methoxyaniline) doped with beta‐cyclodextrin sulfate: electrochemical polymerization and chiroptical properties
Authors: Yuan Guo‐Li , Liu Chen , Xie Wei , Han Peng , Kuramoto Noriyuki 
Published: December 2010

AbstractExcess one‐handed helical poly(2‐methoxyaniline) (PMOA) was synthesized by electrochemical polymerization of 2‐methyoxy aniline in the presence of CDS. PMOA prepared at strong acidic condition shared an opposite excess one‐handed helicity against to that prepared at weak acidic condition. Through studying helix‐inducing dynamic, mechanism for helical opposition was found originating from the dynamic transfer. While predominant dynamic transferred from electrostatic interaction to H‐bonding, PMOA selectively adsorbing the opposite excess one‐handed helix. Dynamic‐transferring tests were carried out by adjusting acid and salt concentration in reaction solution, respectively. Dedoping and redoping cycle was also performed in order to study the chiroptical properties of PMOA after dedoping. The electroactivity of PMOA was checked by cyclic voltammetry. At the same time, PMOA showed interesting chiroptical properties in the states of reduction and oxidation, respectively. ICD spectra indicated that helicity and handedness were well remained in PMOA backbone after redox cycle. Copyright © 2010 John Wiley & Sons, Ltd.
PVC formulation study for the manufacturing of a skin smart structure based in optical fiber elements
Authors: Ferreira da Silva Alexandre , Goncalves Filipe , Mateus Mendes Paulo , Higino Correia Jose 
Published: December 2010

AbstractThe development of smart solutions based on optical fiber technology for any kind of structure such as buildings, aircrafts, or even for human body kinematics, is becoming more and more common. The ability to provide coverings for different structures that can enable monitoring functions beside the esthetic purpose of the covering is an important add‐value characteristic. Nevertheless, an open issue is to find an effective solution for the fabrication and application procedure, preferably that scales at a production level. This article explores the insertion of optical fibers into polymeric PVC foils based on the spread‐coating fabrication process. The success of this integration approach allows the use of photonic technology in different fields with minor application issues. The material choice for the substrate is a crucial step when choosing integrated solution. Three PVC paste formulations were explored in order to guarantee the optimal integration of optical fiber. A high‐viscosity and not monolithic paste formulation emerged as the best choice. This formulation provided the best adhesion, reducing in great scale the surface undulation and paste displacement that the optical fiber tends to do and, its 362% stretch capability is sufficient for special applications, as strain sensitive one. Copyright © 2010 John Wiley & Sons, Ltd.