bluuebunny/crossref_metadata_2025_split huggingface dataset:
Faster flow quantification using sensitivity encoding for velocity‐encoded cine magnetic resonance imaging: In vitro and in vivo validation
Authors: Prakash Ashwin , Garg Ruchira , Marcus Edward N. , Reynolds Glenn , Geva Tal , Powell Andrew J. 
Published: July 2006

AbstractPurposeTo test the agreement between conventional and sensitivity‐encoded (SENSE) velocity encoded cine (VEC) MRI in a flow phantom and in subjects with congenital and acquired heart disease.Materials and MethodsFlow measurements were performed in a 1.5 T scanner using a segmented k‐space VEC MRI sequence and then repeated with a SENSE factor of 2. The flow phantom used a piston pump to generate physiologic arterial waveforms (0.5–4.9 L/min). In the subjects, flow measurements were performed in the ascending aorta (N = 33) and/or the main pulmonary artery (N = 24).ResultsUtilization of SENSE reduced the scan time by 50%. In the phantom, measurements without and with SENSE agreed closely with a mean difference of 0.01 ± 0.08 L/min or 0.12% ± 3.8% (P = 0.68). In the subjects, measurements without and with SENSE also agreed closely with a mean difference of 0.08 ± 0.36 L/min or 1.3% ± 7.2% (P = 0.08). Compared with standard imaging, the use of SENSE reduced the signal‐to‐noise ratio (SNR) by 28% in the phantom (N = 10) and 27% in vivo (N = 22).ConclusionVEC MRI flow measurements with a SENSE factor of 2 were twice as fast and agreed closely with the conventional technique in vitro and in vivo. VEC MRI with SENSE can be used for rapid and reliable quantification of blood flow. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Improved turbo spin‐echo imaging of the heart with motion‐tracking
Authors: Keegan Jennifer , Gatehouse Peter D. , Prasad Sanjay K. , Firmin David N. 
Published: July 2006

AbstractPurposeTo improve dark‐blood and short tau inversion recovery (STIR) prepared turbo spin‐echo (TSE) imaging of the heart, particularly in the basal short‐axis plane where cardiac misregistration between the preparation and imaging phases is high.Materials and MethodsIn the first approach (tracked), the basal short‐axis plane was labeled and tracked over the cardiac cycle. The slice‐selective 180° dark‐blood and STIR preparation pulses were then independently positioned on the appropriately timed labeled images. In the second approach (offset), the preparation pulses were output in the same orientation as the imaging plane, but with a user‐defined slice offset that was derived from the labeled data. Both approaches were compared with the standard untracked dark‐blood STIR TSE sequence (7‐mm slice thickness) in 10 healthy volunteers.ResultsFor typical preparation slice thicknesses, tracked and offset TSE images were superior to the untracked images (both P < 0.01). For the more mobile right ventricle (RV), the image quality of the tracked images was superior to that of the offset images (P < 0.05).ConclusionTracking the through‐plane motion of the heart between preparation and imaging phases improves the quality of thin‐slice basal short‐axis TSE images, particularly for the more mobile RV. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
3D MR sialography protocol for postradiotherapy follow‐up of the salivary duct system
Authors: Astreinidou Eleftheria , Raaymakers Cornelis P.J. , Roesink Judith M. , Terhaard Chris H.J. , Lagendijk Jan J.W. , Bartels Lambertus W. 
Published: July 2006

AbstractPurposeTo develop and evaluate an MR sialography protocol that reproducibly images the parotid and submandibular ducts over time, in 3D. Such a protocol is needed in order to investigate the possible radiation‐induced changes to the salivary ducts in patients receiving radiotherapy to the head‐and‐neck.Materials and MethodsMR sialography was performed on a 1.5‐T MR scanner. Sequence parameters were optimized on 11 healthy volunteers. A 3D water‐selective turbo spin echo (TSE) pulse sequence (TR/TE = 6000 msec/190 msec), using a two‐element circular surface coil was applied twice in one MR session. In order to assess the reproducibility, the same procedure was repeated four to six months later. The quality of the MR sialograms was measured subjectively by developing a visibility scoring system and objectively by the means of contrast‐to‐noise ratio (CNR) of the ducts vs. fat (CNRduct‐fat).ResultsHigh‐quality, 3D MR sialographic images were obtained. The quality of the MR sialograms and the subjective visibility score of the salivary ducts were constant over time. The CNRduct‐fat varied between volunteers (standard deviation, SD 26%) but it was relatively constant per volunteer (SD 5%).ConclusionThe MR sialography protocol presented in this study provides good quality 3D imaging of the major salivary ducts, submandibular duct, and the parotid duct and it can be used for the comparison of the salivary duct system of an individual over time. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Quantitative dynamic contrast‐enhanced MRI in tumor‐bearing rats and mice with inversion recovery TrueFISP and two contrast agents at 4.7 T
Authors: Weidensteiner Claudia , Rausch Martin , McSheehy Paul M.J. , Allegrini Peter R. 
Published: July 2006

AbstractPurposeTo characterize tumor vascularization by dynamic‐contrast enhanced (DCE) MRI using low and medium molecular weight paramagnetic contrast agents (CA) and inversion recovery (IR) true fast imaging with steady state precession (TrueFISP) in tumor‐bearing rats and mice.Materials and MethodsT1 mapping was performed using IR True FISP in phantoms and in vivo at 4.7 T and validated with a segmented IR gradient‐echo (IR GE) method. CA concentration in DCE‐MRI studies in vivo was calculated from time‐series T1 maps using the CAs GdDOTA and P792 (low and medium molecular weight, respectively). Standard vascular input functions (VIFs) were measured in the jugular veins and were used for modeling of the CA kinetics with a two‐compartment model. In rat breast tumors, vascular permeability (transfer constant Ktrans), fractional plasma volume vp, and fractional leakage space ve were quantified and parametric maps were generated.ResultsThe IR TrueFISP T1 was slightly underestimated in phantoms and overestimated in vivo (10%) with respect to IR GE. VIFs showed only small interindividual variation. Mean Ktrans values were 0.062 ± 0.017 min–1 for GdDOTA and 0.015 ± 0.005 min–1 for P792 (N = 12). Mean ve and vp values were 0.15 ± 0.04 (0.09 ± 0.03) and 0.04 ± 0.01 (0.03 ± 0.01) for GdDOTA (P792).ConclusionDCE‐MRI with IR TrueFISP provided absolute values for Ktrans, vp, and ve. Direct comparison between GdDOTA and P792 revealed significant differences in the VIF, model‐fit‐quality, permeability, leakage space, and plasma volume. The larger molecular weight CA P792 appears to be better for measuring tumor vascular parameters. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Inhibition of proteasome and Shaggy/Glycogen synthase kinase‐3β kinase prevents clearance of phosphorylated tau in Drosophila
Authors: Blard Olivier , Frébourg Thierry , Campion Dominique , Lecourtois Magalie 
Published: July 2006

AbstractTauopathies, including Alzheimer's disease (AD), are a group of neurodegenerative disorders characterized by the presence of intraneuronal filamentous inclusions of abnormally phosphorylated tau protein. In AD brains, it has been shown that the level of abnormally phosphorylated tau is higher than in age‐matched control brains, suggesting that abnormally phosphorylated tau is resistant to degradation. By using a Drosophila model of tauopathy, we studied the relationship between tau phosphorylation and degradation. We showed that in vivo reduction of proteasome activity results in an accumulation of high‐molecular‐weight forms of hyperphosphorylated tau. We also found that glycogen synthase kinase (GSK)‐3β‐mediated hyperphosphorylated forms of tau are degradable by the proteasomal machinery. Unexpectedly, GSK‐3β inactivation resulted in a very large accumulation of high‐molecular‐weight species consisting of hyperphosphorylated tau, suggesting that, depending on the kinase(s) involved, tau phosphorylation state affects its degradation differently. We thus propose a model for tauopathies in which, depending on toxic challenges (e.g., oxidative stress, exposure to amyloid peptide, etc.), abnormal phosphorylation of tau by kinases distinct from GSK‐3β leads to progressive accumulation of hyperphosphorylated tau oligomers that are resistant to degradation. © 2006 Wiley‐Liss, Inc.
Implicit consumer preferences and their influence on product choice
Authors: Friese Malte , Wänke Michaela , Plessner Henning 
Published: July 2006

AbstractRecent theories in social psychology assume that people may have two different attitudes toward an object at the same time—one that is explicit and corresponds with deliberative behavior, and one that is implicit and corresponds with spontaneous behavior. The research presented in this article tested this assumption in the consumer domain with an experimental approach. Participants whose explicit and implicit preferences regarding generic food products and well‐known food brands were incongruent were more likely to choose the implicitly preferred brand over the explicitly preferred one when choices were made under time pressure. The opposite was the case when they had ample time to make their choice. On the basis of these results, the discussion stresses the importance of impulsive behavior and implicit measures for research in the area of consumer behavior. © 2006 Wiley Periodicals, Inc.
Some extensions of the improved modified Gauss–Seidel iterative method for H‐matrices
Authors: Sun Li‐Ying 
Published: July 2006

AbstractIn this paper, first we present a convergence theorem of the improved modified Gauss–Seidel iterative method, referred to as the IMGS method, for H‐matrices and compare the range of parameters αi with that of the parameter ω of the SOR iterative method. Then with a more general splitting, the convergence analysis of this method for an H‐matrix and its comparison matrix is given. The spectral radii of them are also compared. Copyright © 2006 John Wiley & Sons, Ltd.
Fetal abnormalities leading to termination of singleton pregnancy: the 7‐year experience of a single medical center
Authors: Vaknin Zvi , Ben‐Ami Ido , Reish Orit , Herman Arie , Maymon Ron 
Published: July 2006

AbstractObjectiveTo assess the distribution of fetal indications leading to termination of pregnancy (TOP) in our institute.MethodsAll pregnant women with singleton pregnancies who underwent TOP due to fetal abnormalities in our institute between January, 1998 and December, 2004 were divided between early TOP (<23 weeks' gestation) and late TOP (≥23 weeks' gestation).ResultsThere were 328 (71%) and 134 (29%) early and late TOPs, respectively. The TOPs were performed at a mean gestational age of 20.1 ± 4.8 weeks. The groups varied significantly in the indications for TOP (p = 0.04), which were primarily structural abnormalities (mostly CNS) followed by chromosomal/genetic defects. Fetal structural abnormalities were more common in the late TOP group (62.7% vs 54.2%) while chromosomal‐genetic defects were more common in the early TOP group (40% vs 29.1%, respectively). Fetal infection (mostly cytomegalovirus) was similar (∼4%) for both groups. The early TOP group had significantly more hydrops, gastrointestinal, face and neck abnormalities, while the late TOP group had significantly more cardiovascular abnormalities (p < 0.01).ConclusionsThe impact of early chromosomal/genetic screening contributes to early TOPs, while midgestation anomaly and cardiac scanning significantly contribute to late TOPs. Fetal infection contributes equally to both categories of TOPs. Copyright © 2006 John Wiley & Sons, Ltd.
Prenatal diagnosis of glycogen storage disease type IV
Authors: Akman H. Orhan , Karadimas Charalampos , Gyftodimou Yolanda , Grigoriadou Maria , Kokotas Haris , Konstantinidou Anastasia , Anninos Hector , Patsouris Efstratios , Thaker Harshwardhan M. , Kaplan Jeffrey B. , Besharat Isaam , Hatzikonstantinou Konstantina , Fotopoulos Spyridon , DiMauro Salvatore , Petersen Michael B. 
Published: July 2006

AbstractBackgroundGlycogen storage disease type IV (GSD‐IV) is a rare autosomal recessive disorder due to mutations in the GBE1 gene causing deficiency of the glycogen branching enzyme (GBE). Prenatal diagnosis has occasionally been performed by the measurement of the GBE activity in cultured chorionic villi (CV) cells.MethodsTwo unrelated probands with severe hypotonia at birth and death during the neonatal period were diagnosed with GSD‐IV on the basis of postmortem histological findings. DNA analysis revealed truncating GBE1 mutations in both families.ResultsPrenatal diagnosis was performed in subsequent pregnancies by determination of branching enzyme activity and DNA analysis of CV or cultured amniocytes. Detailed autopsies of the affected fetuses at 14 and 24 weeks of gestation demonstrated intracellular inclusions of abnormal glycogen characteristic of GSD‐IV.ConclusionPrenatal diagnosis of GSD‐IV by DNA analysis is highly accurate in genetically confirmed cases. Copyright © 2006 John Wiley & Sons, Ltd.
The association between preeclampsia and placental trisomy 16 mosaicism
Authors: Yong Paul J. , Langlois Sylvie , Dadelszen Peter von , Robinson Wendy 
Published: July 2006

AbstractBackgroundPrenatally diagnosed trisomy 16 mosaicism is associated with the increased risk of poor pregnancy outcome including intrauterine growth restriction, intrauterine death and fetal malformation. While maternal preeclampsia has also been reported in some cases, this has not been systematically evaluated.MethodsTo better define the risk of preeclampsia and the clinical course of preeclampsia in these pregnancies and to identify associated clinical variables, we reviewed 25 cases of prenatally diagnosed trisomy 16 mosaicism for which molecular studies were undertaken and sufficient obstetrical data were present to include/exclude the diagnosis of preeclampsia.ResultsSix of 25 (24%) mosaic trisomy 16 cases exhibited preeclampsia as compared to 3 of 44 (7%) matched controls. There were no differences between those mosaic trisomy 16 cases presenting with preeclampsia and those that did not, in terms of the presence/absence of UPD, IUGR, malformation, or trisomy on amniocentesis. Four of the 6 (67%) preeclampsia‐associated fetuses were male, compared with only 4 of 19 (21%) (p = 0.06) nonpreeclampsia case fetuses, and three of these also had hypospadias. The levels of trisomy tended to be high in placentas associated with preeclampsia; however very high levels of placental trisomy were also often seen in the absence of preeclampsia.ConclusionAs it is impossible to predict which subset of cases is at highest risk, all women receiving a prenatal diagnosis of trisomy 16 mosaicism should be closely monitored for signs of preeclampsia. Copyright © 2006 John Wiley & Sons, Ltd.
Free volume microprobe studies on poly(methyl methacrylate)/poly(vinyl chloride) and poly(vinyl chloride)/polystyrene blends
Authors: Kumaraswamy G.N. , Ranganathaiah C. 
Published: July 2006

AbstractBlends of Poly(methyl methacrylate) (PMMA)/Poly(vinyl chloride) (PVC) and Poly(vinyl chloride) (PVC)/Polystyrene (PS) of different compositions were prepared by solution casting technique. The blends were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Positron Lifetime Spectroscopy. DSC data were found to be inadequate to describe whether PMMA/PVC blends are miscible or not, possibly because of the small gap in their glass transition temperatures. On the other hand, PVC/PS blends were clearly found to be immiscible by DSC. FTIR results for PMMA/PVC indicate the possible interactions between the carbonyl group of PMMA and α‐hydrogen of PVC. Free volume data derived from Positron lifetime measurements showed that the PMMA/PVC blends to be miscible in low PVC concentration domain. For the first time, the authors have evaluated the hydrodynamic interaction parameter α, advocated by Wolf and Schnell, Polymer, 42, 8599 (2001), to take into account the friction between the component molecules using the free volume data. This parameter (α) has a high value (−57) at 10 wt% of PVC, which could be taken to read miscibility for PMMA/PVC blends to be high. In the case of PVC/PS blends, the positron results fully support the DSC data to conclude the blends to be immiscible throughout the range of concentration. As expected, the hydrodynamic interaction parameter α does not show any change throughout the concentration in PVC/PS blends, further supporting the idea that α is another suitable parameter in the miscibility study of polymer blends. POLYM. ENG. SCI., 46:1231–1241, 2006. © 2006 Society of Plastics Engineers
Compatibilized poly(ether imide)/amorphous polyamide blends by means of poly(ethylene terephthalate) addition
Authors: Ramiro J. , Eguiazábal J. I. , Nazábal J. 
Published: July 2006

AbstractCompatibilized poly(ether imide)/amorphous polyamide (PEI/a‐PA) blends were obtained in the melt state by substitution of 20% PEI by poly(ethylene terephthalate), PET. The two amorphous phases of the blends comprised both a miscibilized 80/20 PEI/PET blend and an a‐PA‐rich phase in which small amounts of PET and probably PEI were present. The presence of PET in the two phases of most of the blends was the main reason for the clear decrease in the particle size that indicated compatibilization. The smaller interfacial tension of the blends after PET addition also proved that compatibilization had occurred. The deviation of the modulus with respect to the direct rule of mixtures was positive in PEI‐rich blends and negative in the blends very rich in a‐PA. The modulus values were tentatively attributed to a different orientation of the components of the blends in the blends and in the neat state. The clear increases in ductility and the impact strength after PET addition further demonstrated the compatibilization effect of PET. POLYM. ENG. SCI., 46: 1292–1298, 2006. © 2006 Society of Plastics Engineers
Preparation of diblock copolymers consisting of methoxy poly(ethylene glycol) and poly(ε‐caprolactone)/poly(L‐lactide) and their degradation property
Authors: Hyun Hoon , Kim Moon Suk , Jeong Sung Chan , Kim Yu Han , Lee Soo Young , Lee Hai Bang , Khang Gilson 
Published: July 2006

AbstractMethoxy poly(ethylene glycol)‐b‐poly(ε‐caprolactone) (MPEG‐PCL) or MPEG‐b‐poly(L‐lactide) (MPEG‐PLLA) diblock copolymers were prepared by the polymerization of CL or LA, using MPEG as an initiator in the presence of stannous octoate. MPEG‐b‐poly(ε‐caprolactone‐ran‐L‐lactide) (MPEG‐PCLA) diblock copolymers with different chemical composition of PCL and PLLA were also prepared by adjusting the amount of CL and LA from MPEG in the presence of stannous octoate. In degradation study, the degradation of the MPEG‐PCLA diblock copolymers mainly depends on the PCL and PLLA segments present in their structure. MPEG‐PCLA, with intermediate ratio of PCL and PLLA segment, completely degraded after 14 weeks. Meanwhile, partially degraded MPEG‐PCLA segments and parent MPEG segments were observed at higher PCL or PLLA segment contents. Introduction of PLLA into the PCL segments caused a lowering of the crystallinity of the diblock copolymers, thus, inducing a faster incoming of water into the copolymers. We confirmed that the diblock copolymers, with lower degree of crystallinity, have degraded more rapidly. POLYM. ENG. SCI., 46: 1242–1249, 2006. © 2006 Society of Plastics Engineers
Single‐polymer composites based on slowly crystallizing polymers
Authors: Yao Donggang , Li Ruihua , Nagarajan Pratapkumar 
Published: July 2006

AbstractAn approach of using slowly crystallizing polymers to form single‐polymer composites (SPCs) was investigated. The method was demonstrated using poly(ethylene terephthalate) (PET) as a model system, with which two distinct physical forms, namely, amorphous PET films and highly crystalline PET fibers can be readily obtained. Because of the large difference between the rubbery softening temperature of the amorphous phase and the melting temperature of the crystalline phase, the new process is characterized by its wide process window and enhanced manufacturability. The heating temperature and holding time were found to play a profound role in influencing the properties of the SPC. Excellent fiber–matrix interfacial adhesion was obtained at heating temperature 180°C and holding time 10 s. The results also indicated that the heating rate plays a significant role in affecting the fusion and adhesion of the composite. With reduced heating rates, the fusion and adhesion properties are rapidly deteriorated. POLYM. ENG. SCI., 46: 1223–1230, 2006. © 2006 Society of Plastics Engineers
Thermal and shear flow effects on microstructure of a thermotropic liquid crystalline polymer
Authors: Guo Tianren , Naskar Amit K. , Harrison Graham M. , Ogale Amod A. 
Published: July 2006

AbstractThe effects of annealing time and temperature on the texture and transient shear rheological behavior of a thermotropic liquid crystalline polymer were investigated. The texture evolution during annealing included two processes: the reduction of the defect density and the increase of the domain size but decrease of the domain number. We confirmed that the threaded texture caused the first shear stress peak and the shear stress minimum during shear flow startup. More importantly, using the wide‐angle X‐ray diffraction technique, we determined that the second shear stress peak during flow startup can be attributed to the evolution of the molecular orientation. POLYM. ENG. SCI., 46:1215–1222, 2006. © 2006 Society of Plastics Engineers
Crystallization, morphology, and mechanical behavior of polylactide/poly(ε‐caprolactone) blends
Authors: López‐Rodríguez N. , López‐Arraiza A. , Meaurio E. , Sarasua J.R. 
Published: July 2006

AbstractOptically pure polylactides, poly(L‐lactide) (PLLA) and poly(D‐lactide) (PDLA), were blended across the range of compositions with poly(ε‐caprolactone) (PCL) to study their crystallization, morphology, and mechanical behavior. Differential scanning calorimetry and dynamic mechanical analysis (DMA) of the PLA/PCL blends showed two Tgs at positions close to the pure components revealing phase separation. However, a shift in the tan δ peak position by DMA from 64 to 57°C suggests a partial solubility of PCL in the PLA‐rich phase. Scanning electron microscopy reveals phase separation and a transition in the phase morphology from spherical to interconnected domains as the equimolar blend approaches from the outermost compositions. The spherulitic growth of both PLA and PCL in the blends was followed by polarized optical microscopy at 140 and 37°C. From tensile tests at speed of 50 mm/min Young's modulus values between 5.2 and 0.4 GPa, strength values between 56 and 12 MPa, and strain at break values between 1 and 400% were obtained varying the blend composition. The viscoelastic properties (E′ and tan δ) obtained at frequency of 1 Hz by DMA are discussed and are found consistent with composition, phase separation, and crystallization behavior of the blends. POLYM. ENG. SCI., 46:1299–1308, 2006. © 2006 Society of Plastics Engineers