bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of signal‐to‐noise ratio on the accuracy and reproducibility of diffusion tensor imaging–derived fractional anisotropy, mean diffusivity, and principal eigenvector measurements at 1.5T
Authors: Farrell Jonathan A.D. , Landman Bennett A. , Jones Craig K. , Smith Seth A. , Prince Jerry L. , van Zijl Peter C.M. , Mori Susumu 
Published: August 2007

AbstractPurposeTo develop an experimental protocol to calculate the precision and accuracy of fractional anisotropy (FA), mean diffusivity (MD), and the orientation of the principal eigenvector (PEV) as a function of the signal‐to‐noise ratio (SNR) in vivo.Materials and MethodsA healthy male volunteer was scanned in three separate scanning sessions, yielding a total of 45 diffusion tensor imaging (DTI) scans. To provide FA, MD, and PEV as a function of SNR, sequential scans from a scan session were grouped into nonintersecting sets. Analysis of the accuracy and precision of the DTI‐derived contrasts was done in both a voxel‐wise and region of interest (ROI)‐based manner.ResultsAn upward bias of FA and no significant bias in MD were present as SNR decreased, confirming results from simulation‐based studies. Notably, while the precision of the PEV became worse at low SNR, no bias in the PEV orientation was observed. Overall, an accurate and precise quantification of FA values in GM requires substantially more SNR than the quantification of white matter (WM) FA valuesConclusionThis study provides guidance for FA, MD, and PEV quantification and a means to investigate the minimal detectable differences within and across scan sessions as a function of SNR. J. Magn. Reson. Imaging 2007;26:756–767. © 2007 Wiley‐Liss, Inc.
Evaluation of a resistance‐based model for the quantification of pulmonary arterial hypertension using MR flow measurements
Authors: Abolmaali Nasreddin , Seitz Uwe , Esmaeili Anoosh , Kock Martin , Radeloff Daniel , Ackermann Hanns , Vogl Thomas J. 
Published: August 2007

AbstractPurposeTo establish an estimate for the mean pulmonary arterial pressure (mPAP) derived from noninvasive data acquired with magnetic resonance (MR) velocity‐encoded sequences.Materials and MethodsIn seven sedated pigs synchronous catheter‐based invasive pressure measurements (IPM) and noninvasive MR were acquired in the main pulmonary artery (MPA) at different severities of pulmonary arterial hypertension (PAH) that were caused by infusion of thromboxane A2 (TxA2). The invasively measured mPAP was correlated with the noninvasive MR velocity data and linear combination equations (LCE) were computed.ResultsIntravenously applied TxA2 induced a dose dependent level of severity of PAH with an mPAP of up to 54 mmHg without systemic effects. The acceleration time (AT) measured with MR demonstrated the best correlation with the mPAP (r2 = 0.75). The LCE with the highest correlation (R = 0.945, α < 0.01) between IPM and MR revealed a mean difference of 0, a SD of s = 4.66 and a maximal difference of 12.2 mmHg using the Bland‐Altman analysis.ConclusionApplying the identified LCE allowed the estimation of the mPAP in an acute and resistance‐based model of PAH with high accuracy using noninvasive MR velocity‐encoded sequences. J. Magn. Reson. Imaging 2007;26:646–653. © 2007 Wiley‐Liss, Inc.
MRI measurements of tumor size and pharmacokinetic parameters as early predictors of response in breast cancer patients undergoing neoadjuvant anthracycline chemotherapy
Authors: Yu Hon J. , Chen Jeon‐Hor , Mehta Rita S. , Nalcioglu Orhan , Su Min‐Ying 
Published: August 2007

AbstractPurposeTo investigate the value of using changes in three parameters (tumor size, transfer constant (Ktrans), and rate constant (kep)) obtained after the first treatment‐cycle in predicting the final clinical response after two to four cycles of neoadjuvant anthracycline and cyclophosphamide (AC) chemotherapy.Materials and MethodsEarly changes in the three parameters were measured in 29 patients with invasive breast cancer by MRI after one cycle of treatment. Changes were then assessed for their predictive value of final clinical response and compared among patients with four different response patterns, Group 1 = responder (R) after one cycle and also R after four cycles, Group 2 = nonresponder (NR) after one cycle, but eventual R after four cycles, Group 3 = NR after one cycle and still NR after four cycles, and Group 4 = NR after one cycle and determined as NR after two cycles, being switched to the taxane regimen.ResultsPearson's correlation analysis revealed significant correlation between early changes in tumor size and both pharmacokinetic parameters (r = 0.49 and P < 0.01 for Ktrans, r = 0.66 and P < 0.001 for kep). The areas under the receiver operating characteristic (ROC) curve differentiating between R (Groups 1+2) and NR (Groups 3+4) groups using changes in tumor size, Ktrans, and kep were 0.88 (standard error [SE] = 0.06, P < 0.0001), 0.63 (SE = 0.11, P = 0.11), and 0.77 (SE = 0.09, P = 0.001), respectively.ConclusionEarly tumor size change in MRI after one cycle is better response predictor than that of either Ktrans or kep in breast cancer undergoing neoadjuvant chemotherapy using an AC regimen. J. Magn. Reson. Imaging 2007;26:615–623. © 2007 Wiley‐Liss, Inc.
Age, gender, and skeletal variation in bone marrow composition: A preliminary study at 3.0Tesla
Authors: Liney Gary P. , Bernard Clare P. , Manton David J. , Turnbull Lindsay W. , Langton Chris M. 
Published: August 2007

AbstractPurposeTo evaluate the efficacy of MR Spectroscopy (MRS) at 3.0 Tesla for the assessment of normal bone marrow composition and assess the variation in terms of age, gender, and skeletal site.Materials and MethodsA total of 16 normal subjects (aged between eight and 57 years) were investigated on a 3.0 Tesla GE Signa system. To investigate axial and peripheral skeleton differences, non‐water‐suppressed spectra were acquired from single voxels in the calcaneus and lumbar spine. In addition, spectra were acquired at multiple vertebral bodies to assess variation within the lumbar spine. Data was also correlated with bone mineral density (BMD) measured in six subjects using dual‐energy X‐ray absorptiometry (DXA).ResultsFat content was an order of magnitude greater in the heel compared to the spine. An age‐related increase was demonstrated in the spine with values greater in men compared to female subjects. Significant trends in vertebral bodies within the same subjects were also shown, with fat content increasing L5 > L1. Population coefficient of variation (CV) was greater for fat fraction (FF) compared to BMD.ConclusionSignificant normal variations of marrow composition have been demonstrated, which provide important data for the future interpretation of patient investigations. J. Magn. Reson. Imaging 2007;26:787–793. © 2007 Wiley‐Liss, Inc.
Study of ulnar variance with high‐resolution MRI: Correlation with triangular fibrocartilage complex and cartilage of ulnar side of wrist
Authors: Yoshioka Hiroshi , Tanaka Toshikazu , Ueno Teruko , Carrino John A. , Winalski Carl S. , Aliabadi Piran , Lang Philipp , Weissman Barbara N. 
Published: August 2007

AbstractPurposeTo investigate correlations with ulnar variance and the triangular fibrocartilage complex (TFCC) or cartilage of ulnar side of the wrist on high‐resolution MRI with a microscopy coil.Materials and MethodsWe reviewed ulnar variance, TFCC, and cartilage of the ulnar side of the wrist in 93 subjects (29 asymptomatic volunteers and 64 patients with suspected TFCC injury) with high‐resolution MRI using a 47‐mm microscopy surface coil. All MR images were obtained with a 1.5 T scanner. Coronal 2D gradient recalled echo T2*‐weighted images were used for analysis. For qualitative analysis we measured ulnar variance, TFCC angle, thickness in the central portion of TFCC disc proper, and cartilage thickness of the lunate and the ulnar head on MRI and calculated the correlation coefficient between measured values. We also examined the relationship between ulnar variance and age or sex.ResultsHigh‐resolution MR images clearly demonstrated TFCC and cartilage of the wrist and ulnar variance. The mean ulnar variance on MRI was +0.26 mm (range, −4.59 to +3.71 mm). The mean TFCC angle and TFCC thickness were 23.9° (range, −4.6 to +54.1°) and 1.11 mm (range, 0.4 to 3.22 mm), respectively. Ulnar variance and TFCC angle were positively correlated (r = 0.84), and ulnar variance and TFCC thickness were negatively correlated (r = −0.71). However, ulnar variance and lunate or ulnar head cartilage thickness were not significantly correlated.ConclusionHigh‐resolution MRI with a microscopy coil is a useful tool for evaluating the relationship between ulnar variance and ulnar side structures. J. Magn. Reson. Imaging 2007;26:714–719. © 2007 Wiley‐Liss, Inc.
Astrocytes enhance long‐term survival of cholinergic neurons differentiated from human fetal neural stem cells
Authors: Jordan Paivi M. , Cain Lisa D. , Wu Ping 
Published: August 2007

AbstractEstablishment of an in vitro model of human cholinergic neurons would be highly desirable for understanding and developing treatment for Alzheimer's and motoneuron diseases. Previously we reported that the combination of basic fibroblast growth factor (bFGF), heparin, and laminin directs human fetal neural stem cells to form cholinergic neurons. One problem, however, is that long‐term in vitro survival of these cells is low. Our goal for this study was to determine whether astrocytes or their secreted factors enhance differentiation and survival of cholinergic neurons under long‐term differentiation conditions. We demonstrate here that astrocytes or astrocyte conditioned media did not enhance cholinergic differentiation but did increase the long‐term survival of differentiated human neural stem cells, particularly cholinergic neurons. We further show that astrocytes protected long‐term‐differentiated cells from apoptotic cell death, which is at least partially mediated by astrocyte‐secreted bFGF. Our findings indicate that long‐term survival of human stem cell‐derived cholinergic neurons requires trophic factors from nonneuronal cells. This data may provide insights into the development of an in vitro model of long‐term cultured human cholinergic neurons useful for understanding of the mechanisms of cholinergic differentiation and developing treatments for neurological diseases. © 2007 Wiley‐Liss, Inc.
Effects of heat stimulation via microwave applicator on cartilage matrix gene and HSP70 expression in the rabbit knee joint
Authors: Tonomura Hitoshi , Takahashi Kenji A. , Mazda Osam , Arai Yuji , Shin‐Ya Masaharu , Inoue Atsuo , Honjo Kuniaki , Hojo Tatsuya , Imanishi Jiro , Kubo Toshikazu 
Published: August 2007

AbstractThe objective of this study was to investigate the effects of heat stimulation on the expression of extracellular matrix genes and heat‐shock protein 70 (HSP70) in rabbit articular cartilage in vivo. Heat stimulation was applied to the knee joints of Japanese white rabbits for 20 min using a microwave (MW) applicator (2.45‐GHz, 0–80 W). After 8–72 h, the articular cartilage was removed from the knee joints and proteins and total RNA were extracted. As controls, knee joints without heat stimulation were analyzed. The expression of HSP70 was confirmed by real‐time PCR and Western blotting. The expression of proteoglycan core protein (PG) and type II collagen (Col II) was quantified using real‐time PCR to assess cartilage matrix metabolism. Compared to controls, HSP70 expression was higher with more than 40 W of heat stimulation. The expression of PG and Col II mRNA was higher, with more than 20 W of heat stimulation and peaked with 40 W. When quercetin was used to inhibit the induction of HSP70 expression, PG mRNA expression did not increase. External MW application stimulated HSP70 expression in the articular cartilage in vivo. The expression of extracellular matrix genes was increased by appropriate heat stimulation. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:34–41, 2008
Use of a bioscaffold to improve healing of a patellar tendon defect after graft harvest for ACL reconstruction: A study in rabbits
Authors: Karaoglu Sinan , B. Fisher Matthew , Woo Savio L‐Y. , Fu Yin‐Chih , Liang Rui , Abramowitch Steven D. 
Published: August 2007

AbstractFollowing harvest of a bone‐patellar tendon‐bone (BPTB) autograft, the central third of the patellar tendon (PT) does not heal well. The healing tissues also form adhesions to the fat pad and can cause abnormal patellofemoral joint motion. The hypotheses were that a bioscaffold could enhance patellar tendon healing through contact guidance and chemotaxis, and the scaffold could serve as a barrier to decrease adhesion formation between the neo‐PT and infrapatellar fat pad. In 20 New Zealand White rabbits, a central‐third PT defect was created. One strip of porcine small intestinal submucosa (SIS) was attached to both the anterior and posterior sides of the PT defect of the SIS‐treated group (n = 10). For comparison, a central defect was left nontreated (n = 10). At 12 weeks, histomorphology was examined using Masson's trichrome staining. The cross‐sectional area (CSA) was determined with a laser micrometer, and the central BPTB complexes were tested in uniaxial tension. SIS‐treated samples showed a greater amount of healing tissue with denser and well‐oriented collagen fibers and more spindle‐shaped cells. There was no noticeable adhesion formation in the SIS‐treated group. For the nontreated group, there were significantly more and diffuse adhesive formations. The SIS‐treated group also had a 68% increase in neo‐PT CSA, 98% higher stiffness, and 113% higher ultimate load than that in the nontreated group. SIS treatment increased the quantity of healing tissue, improved the histological appearance and biomechanical properties of the neo‐PT, and prevented adhesion formation between the PT and fat pad. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:255–263, 2008
Empirical relationships for soil organic carbon transport from agricultural watersheds in Ohio
Authors: Starr G. C. , Lal R. , Owens L. , Kimble J. 
Published: August 2007

AbstractImproved quantification is needed for long‐term soil organic carbon (SOC) transport in runoff at watershed scales. Coshocton wheel samplers were used to collect runoff samples from no‐till and chisel‐till watersheds in corn (Zea mays) and soybean (Glycine max) rotations over 13 years. Samples were analyzed for SOC, N, P, K, and soil losses. The SOC losses, ranging from 0 to 357 kg ha−1 event−1, were correlated (r2 = 0·80–0·94) in power law relationships with N, P, K, soil loss, and runoff. Two events occurring in corn when soybean and cover crop residue were present in no‐till had combined SOC transport of 460 kg ha−1, nearly double the no‐till losses of a previous 11‐year period and 20 times higher than chisel‐till in the same events. Infrequent, extreme transport events that are not well characterized empirically, particularly in no‐till, can strongly influence hydrologic C transport from agriculture watersheds. Copyright © 2007 John Wiley & Sons, Ltd.
Faserverstärkte oxidkeramische Werkstoffe
Authors: Schmücker M. 
Published: August 2007

AbstractOxidkeramische Werkstoffe zeichnen sich durch hohe thermische und chemische Stabilität aus. Ein quasiduktiles Verformungsverhalten lässt sich durch den Einbau von hochfesten keramischen Langfasern erzielen. Voraussetzung für das quasiduktile, schadenstolerante Deformationsverhalten ist eine relativ schwache Faser/Matrix‐Bindung, damit Mechanismen wie Rissumleitung, Rissverzweigung oder Faser‐„Pull‐out”︁ greifen können. Die Bindung zwischen Fasern und Matrix lässt sich durch geeignete Faserbeschichtungen gezielt einstellen; in einem alternativen Konzept wird jedoch auf die Faserbeschichtung verzichtet und eine hochporöse Matrix eingesetzt. Oxidkeramische Faserverbundwerkstoffe mit hoher Matrixporosität zeigen bemerkenswerte mechanische Eigenschaften; gleichzeitig ist die Herstellung der Keramikverbunde verhältnismäßig einfach und preiswert. WHIPOX ist ein faserverstärkter oxidkeramischer Verbundwerkstoff mit poröser Matrix, der im Deutschen Zentrum für Luft‐ und Raumfahrt entwickelt wurde. Herstellung, Mikrostruktur und Eigenschaften von WHIPOX werden vorgestellt.
An integrated solution for NOx‐reduction and ‐control under lean‐burn conditions
Authors: Saruhan B. , Stranzenbach M. , Mondragón Rodríguez G. C. 
Published: August 2007

AbstractUpcoming emission regulations order highly effective NOx‐reduction systems in lean‐burn engines requiring new catalytic materials and integrated control of the reduction process. Thus, new approaches for NOx‐reduction and its monitoring over an On‐Board‐Diagnostic (OBD) system are suggested throughout the globe. A promising attempt is the development of a catalytic system having an integrated NOx‐sensor, based on selective catalytic reduction process and impedance sensors. The study displays the results achieved both with a perovskite type of self‐regenerative catalyst functioning by H2‐reductant and with impedance NOx‐sensors. The catalysts were tested at the temperature range of 150 °C to 360 °C yielding NOx conversion rates of 92 % with high selectivity to N2. Impedance sensors having NiCr2O4‐ and NiO‐SE and PYSZ‐ and FYSZ‐electrolytes are developed and tested at 600 °C under lean atmosphere (5 vol. % O2). Better sensing behaviour towards NO and lower cross‐selectivity towards O2, CO, CO2 and CH4 have been observed with sensors having NiO‐SE.
Vorhersagemodell für die Wachstumsraten kurzer Risse auf der Basis von Kmax‐konstant‐Versuchen an M(T)‐Proben
Authors: Tesch A. , Pippan R. , Trautmann K.‐H. , Döker H. 
Published: August 2007

AbstractDas Ermüdungsrisswachstumsverhalten von kurzen Rissen in den Aluminiumlegierungen Al 6013‐T6 und Al 2524‐T351 wurde untersucht. Ziel war es die Ermüdungsrisswachstumsraten von kurzen Eckrissen bei Spannungsverhältnissen von R = 0,1, R = 0,7 und R = 0,8 zu bestimmen und einen Weg zu finden, diese Wachstumsraten auf der Grundlage von Ermüdungsrisswachstumskurven von langen Rissen vorherzusagen. In Kurzrissproben, ähnlich M(T)‐Proben, wurden an einer Seite einer Bohrung (Ø = 4,8 mm) durch zyklische Druckbelastungen (R = 20) Eckrisse eingebracht. Kerbe und Anrisse zusammen waren kleiner als 100 μm. Unter anderen Methoden wurde eine komplett neue Methode, ein fokussierter Ionenstrahl, verwendet, um die sehr kleinen Kerben (10 μm – 50 μm) in die Proben zu schneiden. Die Ergebnisse aus den Ermüdungsrisswachstumsversuchen mit den Kurzrissproben wurden mit Ermüdungsrisswachstumsdaten von Proben mit langen Rissen verglichen. Die kurzen Risse zeigten Rissfortschritt bei ΔK‐Werten unterhalb der Schwellenwerte für lange Risse beim gleichen Spannungsverhältnis. Sie wuchsen außerdem schneller als lange Risse bei den gleichen ΔK‐Werten und Spannungsverhältnissen. Ein Modell auf Basis von Kmax‐konstant‐Versuchen wurde entwickelt, mit welchem eine gute und konservative Vorhersage der Kurzrisswachstumsraten möglich ist.
Thermal conductivity issues of EB‐PVD thermal barrier coatings
Authors: Schulz U. , Rätzer‐Scheibe H.‐J. , Saruhan B. , Renteria A. F. 
Published: August 2007

AbstractThe thermal conductivity of electron‐beam physical vapor deposited (EB‐PVD) thermal barrier coatings (TBCs) was investigated by the Laser Flash technique. Sample type and methodology of data analyses as well as atmosphere during the measurement have some influence on the data. A large variation of the thermal conductivity was found by changes in TBC microstructure. Exposure at high temperature caused sintering of the porous microstructure that finally increased thermal conductivity up to 30 %. EB‐PVD TBCs show a distinct thickness dependence of the thermal conductivity due to the anisotropic microstructure in thickness direction. Thin TBCs had a 20 % lower thermal conductivity than thick coatings. New compositions of the ceramic top layer offer the largest potential to lower thermal conductivity. Values down to 0.8W/(mK) have been already demonstrated with virgin coatings of pyrochlore compositions.
Verfahren zur vollständigen Ermittlung der R‐Abhängigkeit des Rissausbreitungsverhaltens mit nur einer Probe
Authors: Tesch A. , Pippan R. , Döker H. 
Published: August 2007

AbstractEin neues Prüfungskonzept für Ermüdungsrisswachstumsversuche ermöglicht es mit nur einer Probe für den gesamten Bereich des Spannungsverhältnisses von R = 0,9 bis R = ‐1 Ermüdungsrisswachstumskurven (da/dN‐ΔK‐Kurven) für jedes beliebige R‐Verhältnis zu erstellen. Zusätzlich erhält man auch die Schwellenwerte der Spannungsintensitätsschwingbreite ΔKthals Funktion von R und Kmax. In Kombination mit einer Methode zur kontinuierlichen Risslängenbestimmung, wie der Gleichstrompotenzialmethode, erfordert dieses Verfahren sehr geringen Personal‐ und Zeitaufwand. Das Prüfungskonzept besteht aus einer Aneinanderreihung von Kmax‐konstant‐Versuchen. Da die Kmax‐Werte stufenweise ansteigen, sollte es bei diesem Verfahren keine Lastfolgeeffekte geben. Die ermittelten Daten stimmen sehr gut mit Ergebnissen aus da/dN‐ΔK‐Versuchen, die nach der ASTM Norm E 647 mit mehreren Proben durchgeführten wurden, überein. Die Versuche erfüllen alle Bedingungen der ASTM E 647.
WHIPOX®: Ein faserverstärkter oxidkeramischer Werkstoff für Hochtemperatur– Langzeitanwendungen
Authors: Göring J. , Hackemann S. , Kanka B. 
Published: August 2007

AbstractAm Institut für Werkstoff‐Forschung des Deutschen Zentrums für Luft‐ und Raumfahrt (DLR) wurde der oxidkeramische Faserverbundwerkstoff WHIPOX® (Wound Highly Porous Oxide Ceramic Matrix Composite) bis zur Bauteilreife entwickelt. Neben den Anwendungen in Fluggasturbinen, Wiedereintrittsfahrzeugen und bei Flugkörpern, die in interdisziplinären Projekten im DLR bearbeitet werden, wurde das Material auch für den Einsatz in nicht‐luft‐ und raumfahrtspezifischen Anwendungen erfolgreich getestet. Die spezifische und einzigartige Eigenschaftskombination der faserverstärkten Oxidkeramik ermöglicht neue innovative Lösungsansätze bei Materialproblemen im Industrieofenbau, metallurgischen Anlagenbau, in der Filtertechnik, beim Brandschutz, bei Katalysatoren und Rußfiltern, in der Elektrotechnik und bei medizinischen Anwendungen. Im Bereich des Industrieofenbaus werden bereits Hochgeschwindigkeitsbrennerdüsen von einem Keramikhersteller in Lizenz gefertigt.
Control of thermoelectric properties in ZrO2/CoSb3 nano‐dispersed composites
Authors: Stiewe C. , He Z. , Platzek D. , Karpinski G. , Müller E. , Li S. , Toprak M. , Muhammed M. 
Published: August 2007

AbstractNano‐dispersed ZrO2/CoSb3 composites of various composition were prepared by uniaxial hot pressing of nano‐sized powders of thermoelectric CoSb3 intermixed with ceramic nano‐powders. The phase purity, the microstructure, and the temperature dependent transport parameters of the composites were investigated. Non‐dispersed samples from nano‐sized CoSb3 powders show higher electrical conductivity compared to melt‐grown material which is attributed to the presence of a small excess of metallic Sb, but they exhibit lower thermal conductivity due to the fine‐grained structure. Addition of 5 at.‐% ZrO2 enhances the ratio of electrical to thermal conductivity, whereas hardly affects the Seebeck coefficient. In this manner the nano‐dispersion method provides an effective approach to improving the material´s thermoelectric performance.