bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproducibility of wall shear stress assessment with the paraboloid method in the internal carotid artery with velocity encoded MRI in healthy young individuals
Authors: Box Frieke M.A. , van der Geest Rob J. , van der Grond Jeroen , van Osch Matthias J.P. , Zwinderman Aeilko H. , Palm‐Meinders Inge H. , Doornbos Joost , Blauw Gerard‐Jan , van Buchem Mark A. , Reiber Johan H.C. 
Published: August 2007

AbstractPurposeTo verify whether wall shear stress (WSS) can be assessed in a reproducible manner using automatic model‐based segmentation of phase‐contrast MR images by determination of flow volume and maximum flow velocity (Vmax) in cross‐sections of these vessels.Materials and MethodsThe approach is based on fitting a 3D paraboloid to the actual velocity profiles and on determining Vmax. WSS was measured in the internal carotid arteries of two groups of healthy young volunteers. The reproducibility of rescanning and repositioning was studied in the first group. In the second group a 1‐week and a 1‐month interval was investigated. Reproducibility was calculated by the intraclass correlation (ICC).ResultsThe flow volume, Vmax, and WSS averaged over the cardiac cycle were found to be 287.8 ± 29.7 mL/min, 37.0 ± 4.6 cm/s, and 1.13 ± 0.16 Pa, respectively. The diastolic WSS varied between 1.00 ± 0.21 Pa without averaging to 0.88 ± 0.16 Pa with temporal and spatial averaging. Systolic WSS was 1.67 ± 0.33 Pa without averaging and 1.67 ± 0.25 Pa with averaging. ICC varied between 0.58 and 0.87 without averaging and between 0.75 and 0.90 with averaging for WSS.ConclusionWSS in MR images of the internal carotid artery can be assessed semiautomatically with good to excellent reproducibility without inter‐ or intraobserver variability using model‐based postprocessing. J. Magn. Reson. Imaging 2007;26:598–605. © 2007 Wiley‐Liss, Inc.
Negative electrospray ionization tandem mass spectrometric investigation of ent‐kaurane diterpenoids from the genus Isodon
Authors: Zhou Yan , Huang Sheng‐Xiong , Li Li‐Mei , Yang Jing , Liu Xin , Peng Shu‐Lin , Ding Li‐Sheng , Sun Han‐Dong 
Published: August 2007

Abstractent‐Kaurane diterpenoids are a class of natural compounds isolated from genus Isodon, which have been found to have important bioactivities. Negative electrospray ionization tandem mass spectrometry ((−)ESI‐MSn) was used to investigate the fragmentation pattern of C‐20‐nonoxygenated ent‐kauranes and two subtypes of C‐20‐oxygenated ent‐kauranes by using an ion trap instrument and accurate mass measurement on an ESI‐Q‐time‐of‐flight (TOF) mass spectrometer. The analysis revealed that loss of CH2O or CO2 is the predominant process for 7, 20‐epoxy and 7, 20 : 14, 20‐diepoxy subgroup of C‐20‐oxygenated ent‐kauranes. In addition, compounds of C‐20‐nonoxygenated ent‐kauranes with a conserved core structure but different substituent groups, such as a hydroxyl, aldehyde, carboxyl, and acetyl moiety, resulted in diagnostic product ions through losses of H2O, CO, CO2, and AcOH, respectively. This work clearly demonstrates the utility of tandem mass spectrometry for studies on the rationalization of the diagnostic fragmentation of a series of compounds from two main types of the ent‐kaurane diterpenoids. Copyright © 2007 John Wiley & Sons, Ltd.
Ranking the AR4 climate models over the Murray‐Darling Basin using simulated maximum temperature, minimum temperature and precipitation
Authors: Maxino C. C. , McAvaney B. J. , Pitman A. J. , Perkins S. E. 
Published: August 2007

AbstractWe assess the capacity of models submitted for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4), to simulate the maximum and minimum temperatures and precipitation over the Murray‐Darling Basin (Australia). We use daily data from the AR4 to calculate the mean of these three quantities, but we also derive probability density functions (PDFs) for each variable. We quantify the skill of each climate model to simulate the probability density function as a basis of assessing those models with significant capacity over the basin. We show that Commonwealth Scientific and Industrial Research Organization (CSIRO), Insitut Pierre Simon Laplace (IPSL), and MIROC‐m capture the observed PDFs of maximum and minimum temperature and precipitation relatively well. Other models capture one or two of these variables well but show limitations, or could not be assessed, in a third. We, therefore, recommend these three models to users of model results, but note that this recommendation is limited to this basin. However, our methodology provides quite a straightforward and quantitatively based means to choose climate models for impact assessment in any data‐rich region. Specifically, we note that to demonstrate skill in simulating the daily derived PDFs is far more challenging than just simulating the mean (as a model can simulate the mean well by averaging large biases of opposite sign). Our method therefore provides a more robust foundation for using a model in impacts assessment. Copyright © 2007 Royal Meteorological Society
Isolation and characterization of connective tissue progenitor cells derived from human fracture‐induced hemarthrosis in vitro
Authors: Lee Sang Yang , Miwa Masahiko , Sakai Yoshitada , Kuroda Ryosuke , Oe Keisuke , Niikura Takahiro , Matsumoto Tomoyuki , Fujioka Hiroyuki , Doita Minoru , Kurosaka Masahiro 
Published: August 2007

AbstractIn our search for alternative sources of connective tissue progenitor cells that can be obtained with minimal invasion, we studied human intraarticular fracture‐induced hemarthrosis of the knee and attempted to isolate connective tissue progenitors from the hemarthrosis. Hemarthrosis was aspirated from the knee joints of 13 patients suffering from intraarticular osteochondral fractures of the knee. Mononuclear cells were isolated from the aspirated hemarthrosis by density gradient separation, and cultured. We were able to obtain fibroblastic adherent cells from the mononuclear cell fractions. Flow cytometry analysis after in vitro expansion on tissue culture plastic revealed that the fibroblastic cells were positive for CD29, CD44, CD105, and CD166, and negative for CD14, CD34, CD45, and CD133. These cells could differentiate in vitro into osteogenic, chondrogenic, and adipogenic cells in the presence of lineage‐specific induction factors. These results demonstrate that human intraarticular fracture‐induced knee hemarthrosis contains connective tissue progenitor cells with morphologic features, immunophenotypic markers, and differentiation potential that are similar to bone marrow stromal cells. This suggests that hemarthrosis, which is easy to harvest without unnecessary invasion to the patient, has possible future clinical applications such as in tissue‐engineered therapies for severe osteochondral defects, posttraumatic osteoarthritis, and delayed fracture unions or nonunions. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:190–199, 2008
Static knee alignment is associated with the risk of unicompartmental knee cartilage defects
Authors: Janakiramanan Neela , Teichtahl Andrew J. , Wluka Anita E. , Ding Changhai , Jones Graeme , Davis Susan R. , Cicuttini Flavia M. 
Published: August 2007

AbstractAlthough knee malalignment is a risk factor for the progression of unicompartmental knee osteoarthritis (OA), it is unclear how this relationship is mediated. Cartilage defects are known to predate cartilage loss and the onset of knee OA, and it may be that knee malalignment increases the risk of unicompartmental knee cartilage defects. Knee radiographs and MRI were performed on a total of 202 subjects, 36.6% of whom had radiographic knee OA, to determine the relationship between static knee alignment and knee cartilage defects. Analyses were performed for the entire cohort, as well as for healthy and OA subgroups. For every 1° increase in a valgus direction, there was an associated reduced risk of the presence of cartilage defects in the medial compartment of subjects with knee OA (p = 0.02), healthy subjects (p = 0.002), and the combined (p < 0.001) group. Moreover, for every 1° increase in a valgus direction, there was an associated increased risk of the presence of lateral cartilage defects in the OA group (p = 0.006), although the relationship between change toward genu valgum and lateral compartment cartilage defects did not persist for the healthy group (p = 0.16). This cross‐sectional study has demonstrated that knee alignment is associated with the risk for compartment specific knee cartilage defects in both healthy and arthritic people. Given that the natural history of cartilage volume reduction appears to be predated by the presence of cartilage defects, whether knee alignment affects the longitudinal progression from cartilage defects to cartilage loss requires further examination. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:225–230, 2008
Characterization of bixin by LC‐MS and LC‐NMR
Authors: Rehbein Jens , Dietrich Benjamin , Grynbaum Marc David , Hentschel Petra , Holtin Karsten , Kuehnle Maximilian , Schuler Paul , Bayer Marc , Albert Klaus 
Published: August 2007

AbstractAn overview upon modern analytical techniques for the isolation, separation, and structural identification of the essential bioactive carotenoid bixin is given. Isolation from biological matrices is performed by matrix solid phase dispersion (MSPD). The extract is separated with shape‐selective C30 columns. Structural assignment of the separated compounds is done by online LC‐MS and capillary HPLC‐NMR.
Comparison of continuous‐flow microextraction and static liquid‐phase microextraction for the determination of p‐toluidine in Chlamydomonas reinhardtii
Authors: Liu Xiujuan , Chen Xiaowen , Yang Shao , Wang Xuedong 
Published: August 2007

AbstractIn this study, two microextraction methods, viz. continuous‐flow microextraction (CFME) and static liquid‐phase microextraction (s‐LPME), were optimized and compared for the determination of p‐toluidine in water and Chlamydomonas reinhardtii samples. The calibration curve for p‐toluidine was linear in the concentration range of 0.01–5 μg/mL, and the squared regression coefficients (r2) for the lines were up to 0.999 for both CFME and s‐LPME treatments. Detection limits in CFME and s‐LPME were 8.2 ng/mL and 4.9 ng/mL, based on a signal‐to‐noise (S/N) ratio of 3, respectively. The precision was tested, in five replicates, by analysis of a 100‐ng/mL standard solution of p‐toluidine and the relative standard deviations were 5.43 and 3.08% for CFME and s‐LPME, respectively. The concentration factors were 5.5 and 14.4 for CFME and s‐LPME, respectively. s‐LPME has a higher extraction efficiency, lower detection limit, and higher concentration factor than that of CFME. Additionally, the s‐LPME method is precise and reproducible, and requires only a 3.0‐μL microdrop of extraction solvent. Therefore, this procedure is more convenient in use, and viable for qualitative and quantitative analysis of p‐toluidine in water and biota samples.
Separation and evaluation of free radical‐scavenging activity of phenol components of green, brown, and black leaves of Bergenia crassifolia by using HPTLC‐DPPH• method
Authors: Pozharitskaya Olga N. , Ivanova Svetlana A. , Shikov Alexander N. , Makarov Valery G. , Galambosi Bertalan 
Published: August 2007

AbstractA new procedure has been developed to separate and quantify the free radical‐scavenging activity of individual compounds from green, brown, and black leaves of Bergenia crassifolia based on the combination of high performance TLC (HPTLC) with a diode array detector (DAD) and postchromatographic 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH•) derivatization. Free gallic and ellagic acids, arbutin, hydroquinone, and bergenin in the B. crassifolia leaves' extracts were separated by HPTLC and identified. All compounds of the extract excluding bergenin were capable of scavenging DPPH∗︁ radicals. From the estimated ID50 values, it can be seen that the increasing order of activity was gallic acid > arbutin > ellagic acid > hydroquinone > ascorbic acid. The antiradical activity of leaves of B. crassifolia is probably associated to the presence of phenol.
Analysis of adenosine by RP‐HPLC method and its application to the study of adenosine kinase kinetics
Authors: Marin Rodrigo Miguel , Franchini Kleber Gomes , Rocco Silvana Aparecida 
Published: August 2007

AbstractAn RP‐HPLC method for the analysis of adenosine (ADO) has been developed and validated. In the present study, we report an RP‐HPLC‐based method with modifications of mobile phase and shorter retention time that substantially improved the efficiency of ADO analysis. The HPLC separation of the ADO was achieved on a C18 column, using a mobile phase consisting of water, containing 7% v/v ACN, at a flow rate of 0.8 mL/min. The column effluent was monitored by UV detection at 260 nm. A linear response was achieved over the concentration range of 0.25–100.00 μmol/L. The analytical method inter‐ and intra‐run accuracy and precision were better than ± 15%. The LOQ was 0.25 μmol/L, with ADO detection in the range of 6.25 pmol per sample. The method has been applied to the study of adenosine kinase (AK) kinetics.
Effects of microtopography and erosion on seedling colonisation and survival in the volcano Usu, northern Japan, after the 1977–78 eruptions
Authors: Tsuyuzaki S. , Haruki M. 
Published: August 2007

AbstractThe effects of microtopographical characteristics of the thick accumulation of ash and pumice, which were produced from 1977–78 eruptions, on seedling emergence and survival were monitored on the volcano Usu, northern Japan, 10 years after the eruptions. The characteristics included microtopography, texture of volcanic deposits on ground surface, volcanic‐deposit movements, water content on ground surface and chemical nature of volcanic deposits (ignition loss, P, K and pH). Polygonum sachalinense showed a higher seed germination percentage on finer‐particle ground surface under lab conditions, and Petasites japonicus var. giganteus germinated well on the ground surface with any particle sizes. However, in the field, the seedling densities of those two species and Anaphalis margaritacea var. angustior (three dominant species in this region) were higher on the sites with coarse particles and/or the rill inside the crater basin. The seedling germination timing and space overlapped among these species in the field. Those facts suggested that the seedling colonisation pattern was influenced more by the topographical characteristics of ground surface rather than the germination abilities. The amount of organic matter in the volcanic deposits was very low, even 11 years after the eruptions, and was not related to microtopography, suggesting that the effects of organic matter on seedling emergence did not differ along microtopographical characteristics. Inside of rills, higher water content seemed to be more advantageous for seed germination of those species. Volcanic deposits were physically stable in summer, but were heavily eroded after winter due to snowmelt. Most seedlings did not overwinter in the inside of rills with pumice where the volcanic deposits eroded intensively, indicating that the patterns of land degradation by melting snow should be mentioned carefully even with narrow scale. Copyright © 2007 John Wiley & Sons, Ltd.
Oxidation protective coatings for γ‐TiAl – recent trends
Authors: Fröhlich M. , Ebach‐Stahl A. , Braun R. , Leyens C. 
Published: August 2007

AbstractEngine designers show continued interest in γ‐TiAl based titanium aluminides as light–weight structural materials to be used at moderately elevated temperatures. Although alloy development has made significant progress in terms of mechanical properties and environmental resistance, protective coatings have been developed that help to extend the lifetime of these alloys significantly. The major challenge of coating development is to prevent the formation of fast growing titania. Furthermore, changes of coating chemistries at high temperatures have to be considered in order to avoid rapid degradation of the coatings due to interdiffusion between substrate and coating.The paper describes recent work of the authors on different coatings produced by means of magnetron sputter technique. Thin ceramic Ti‐Al‐Cr‐Y‐N layers tested at 900 °C exhibited poor oxidation resistance. In contrast, intermetallic Ti‐Al‐Cr, Si‐based and aluminum rich Ti‐Al coatings were tested at exposure temperatures up to 950 °C for 1000h resulting in reasonable and partially excellent oxidation behaviour.
Environmentally assisted cracking of aluminium alloys
Authors: Braun R. 
Published: August 2007

AbstractA short review of the stress corrosion cracking (SCC) behaviour of aluminium alloys is given. Mechanisms of environmentally assisted cracking are outlined. For aluminium alloys, in which stress corrosion cracks propagate predominantly along grain boundaries, anodic dissolution and hydrogen embrittlement have been proposed. Transgranular stress corrosion cracking occurring at severe loading conditions has found particular interest concerning localised corrosion‐deformation interactions. Accelerated test methods for assessing the SCC behaviour are described, including the slow strain rate testing technique and the breaking load method. Results of recent studies on environmentally assisted cracking of aluminium alloys are summarised. Most of the work published in the last two decades has been on aluminium‐lithium based alloys and improved high strength Al‐Zn‐Mg‐Cu alloys in corrosion resistant retrogressed and re‐aged tempers.
Faser‐ und drahtverstärkte Kupferlegierungen als Wärmesenke für Fusionsreaktoren
Authors: Peters P. W. M. , Hemptenmacher J. , Schurmann H. 
Published: August 2007

AbstractDie CuCr1Zr‐Legierung wird wegen ihrer mechanischen Eigenschaften und Leitfähigkeit (310–330 W/m/K bei 20 °C) in bestehenden und zukünftigen experimentellen Fusionsreaktoren (wie z.B. ITER) als Wärmesenke eingesetzt. Diese warmaushärtbare Legierung ist wegen der Alterung nur bis zu Temperaturen von 450 °C einsetzbar. Eine Möglichkeit die Einsatztemperatur zu erhöhen (angestrebt wird 550 °C) besteht in einer Verstärkung mit SiC‐Fasern oder W‐Drähten. Mit Hilfe von mit der CuCr1Zr‐Legierung beschichteten SiC (SCS‐6)‐Fasern und W‐Drähten (beide mit einem Durchmesser von ∼150 μm) wurden Cu‐MMCs (Kupfer‐Metallmatrix‐Verbundwerkstoffe) hergestellt und deren Eigenschaften (Grenzflächeneigenschaften, Festigkeit, thermische Leitfähigkeit) ermittelt. Nach der Konsolidierung durch Heiß‐Isostatisches‐Pressen ist die Kupfermatrix gealtert, so dass eine zusätzliche Warmaushärtung notwendig ist, um optimale Verbundeigenschaften zu realisieren. Die Festigkeit der verschiedenen Cu‐MMCs wurden in Abhängigkeit des Volumenanteils der Verstärkungselemente bestimmt. Die Zugfestigkeit steigt mit zunehmendem Volumenanteil der Fasern oder Drähte und erreicht z. B. eine Zugfestigkeit von 1000 MPa bei einem Faservolumenanteil von 24 % oder Drahtvolumenanteil von 27 %. Wärmeleitfähigkeitsmessungen, mit Hilfe einer Laserflash‐Anlage durchgeführt, zeigen, dass die thermische Leitfähigkeit mit zunehmendem Faservolumenanteil abnimmt (sie beträgt z. B. 200 W/m/K bei einem SiC‐Faservolumenanteil von 30 %). Die W‐drahtverstärkte CuCr1Zr‐Legierung wird auf Grund der besseren Leitfähigkeit und Grenzflächeneigenschaften ausgewählt, um das Potential von Cu‐MMCs für Wärmesenken in einer ersten Entwurfstudie am Beispiel unterschiedlicher Divertorbautypen abzuschätzen.
Statistical framework and noise sensitivity of the amplitude radial correlation contrast method
Authors: Kipervaser Zeev Gideon , Pelled Galit , Goelman Gadi 
Published: August 2007

AbstractA statistical framework for the amplitude radial correlation contrast (RCC) method, which integrates a conventional pixel threshold approach with cluster‐size statistics, is presented. The RCC method uses functional MRI (fMRI) data to group neighboring voxels in terms of their degree of temporal cross correlation and compares coherences in different brain states (e.g., stimulation OFF vs. ON). By defining the RCC correlation map as the difference between two RCC images, the map distribution of two OFF states is shown to be normal, enabling the definition of the pixel cutoff. The empirical cluster‐size null distribution obtained after the application of the pixel cutoff is used to define a cluster‐size cutoff that allows 5% false positives. Assuming that the fMRI signal equals the task‐induced response plus noise, an analytical expression of amplitude‐RCC dependency on noise is obtained and used to define the pixel threshold. In vivo and ex vivo data obtained during rat forepaw electric stimulation are used to fine‐tune this threshold. Calculating the spatial coherences within in vivo and ex vivo images shows enhanced coherence in the in vivo data, but no dependency on the anesthesia method, magnetic field strength, or depth of anesthesia, strengthening the generality of the proposed cutoffs. Magn Reson Med 58:554–561, 2007. © 2007 Wiley‐Liss, Inc.
Optimized balanced steady‐state free precession magnetization transfer imaging
Authors: Bieri O. , Scheffler K. 
Published: August 2007

AbstractBalanced steady‐state free precession (bSSFP) suffers from a considerable signal loss in tissues. This apparent signal reduction originates from magnetization transfer (MT) and may be reduced by an increase in repetition time or by a reduction in flip angle. In this work, MT effects in bSSFP are modulated by a modification of the bSSFP sequence scheme. Strong signal attenuations are achieved with short radio frequency (RF) pulses in combination with short repetition times, whereas near full, i.e., MT‐free, bSSFP signal is obtained by a considerable prolongation of the RF pulse duration. Similar to standard methods, the MT ratio (MTR) in bSSFP depends on several sequence parameters. Optimized bSSFP protocol settings are derived that can be applied to various tissues yielding maximal sensitivity to MT while minimizing contribution from other impurities, such as off‐resonances. Evaluation of MT in human brain using such optimized bSSFP protocols shows high correlation with MTR values from commonly used gradient echo (GRE) sequences. In summary, a novel method to generate MTR maps using bSSFP image acquisitions is presented and factors that optimize and influence this contrast are discussed. Magn Reson Med 58:511–518, 2007. © 2007 Wiley‐Liss, Inc.
Oxygenation and hematocrit dependence of transverse relaxation rates of blood at 3T
Authors: Zhao Jason M. , Clingman Chekesha S. , Närväinen M. Johanna , Kauppinen Risto A. , van Zijl Peter C.M. 
Published: August 2007

AbstractKnowledge of the transverse relaxation rates R2 and R of blood is relevant for quantitative assessment of functional MRI (fMRI) results, including calibration of blood oxygenation and measurement of tissue oxygen extraction fractions (OEFs). In a temperature controlled circulation system, these rates were measured for blood in vitro at 3T under conditions akin to the physiological state. Single spin echo (SE) and gradient echo (GRE) sequences were used to determine R2 and R, respectively. Both rates varied quadratically with deoxygenation, and changes in R were found to be due predominantly to changes in R2. These data were used to estimate intravascular blood oxygenation level dependent (BOLD) contributions during visual activation. Due to the large R in venous blood, intravascular SE BOLD signal changes were larger than GRE effects at echo times above 30 ms. When including extravascular effects to estimate the total BOLD effect, GRE BOLD dominated due to the large tissue volume fraction. Magn Reson Med 58:592–596, 2007. © 2007 Wiley‐Liss, Inc.