bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusion tensor imaging using partial Fourier STEAM MRI with projection onto convex subsets reconstruction
Authors: Rieseberg Susanne , Merboldt Klaus‐Dietmar , Küntzel Matthias , Frahm Jens 
Published: July 2005

AbstractDiffusion‐weighted single‐shot STEAM MRI allows for diffusion mapping of the human brain without sensitivity to resonance offset effects. In order to compensate for its inherently lower SNR and speed than echo‐planar imaging, this work describes the use of partial Fourier encoding in combination with image reconstruction by the projection onto convex subsets algorithm. The method overcomes phase distortions in diffusion‐weighted partial Fourier acquisitions that disturb the conjugate complex symmetry of k‐space and preclude the use of respective reconstruction techniques. In comparison with full Fourier encoding and a static flip angle for the STEAM readout pulses, experimental results at 2.9 T demonstrate a gain in relative SNR per unit time by 20% for 5/8 phase encoding with optimized variable flip angles. Simultaneously, the imaging time is reduced from about 670 ms (80 echoes) to 440 ms (50 echoes). Current implementations at 2 × 2 mm2 in‐plane resolution comprise a protocol for clinical anisotropy studies (12 diffusion‐encoding gradient directions at 1000 s mm−2) covering 18 sections of 4‐mm thickness within a measurement time of 8.5 min (5 averages) and a version optimized for fiber tracking using 24 gradient directions and 38 sections of 2‐mm thickness yielding a measurement time of 29.5 min (4 averages). Magn Reson Med 54:486–490, 2005. © 2005 Wiley‐Liss, Inc.
Contrast‐enhanced 4D radial coronary artery imaging at 3.0 T within a single breath‐hold
Authors: Bi Xiaoming , Park Jaeseok , Larson Andrew C. , Zhang Qiang , Simonetti Orlando , Li Debiao 
Published: July 2005

AbstractCoronary magnetic resonance angiography data are usually acquired during mid‐diastole of each heartbeat to minimize cardiac motion related artifacts. The proper trigger delay time, which may vary widely among subjects, must be determined individually for each subject before data acquisition to achieve optimal image quality. These complications could be resolved by acquiring contiguous cardiac phase images through the cardiac cycle. In this study, we used a radial sampling technique to acquire 3D cine coronary artery images at 3 T within a single breath‐hold. An extravascular, paramagnetic contrast agent was i.v. administered to improve the blood signal intensity. Relatively high temporal resolution and spatial resolution were achieved simultaneously with radial sampling, parallel data acquisition, and interleaved sliding window image reconstruction. Volunteer studies demonstrate the feasibility of this technique in acquiring 4D coronary artery images and the flexibility in postprocessing of 3D image sets. Magn Reson Med 54:470–475, 2005. © 2005 Wiley‐Liss, Inc.
Magnetic resonance imaging and mathematical modeling of progressive formalin fixation of the human brain
Authors: Yong‐Hing Charlotte J. , Obenaus Andre , Stryker Rodrick , Tong Karen , Sarty Gordon E. 
Published: July 2005

AbstractThe temporal magnetic resonance (MR) appearance of human brain tissue during formalin fixation was measured and modeled using a diffusion mathematical model of formalin fixation. Coronal MR images of three human brains before formalin fixation and at multiple time points thereafter were acquired. T1 relaxation, T2 relaxation, water apparent diffusion coefficient (ADC), and proton density (PD) maps were calculated. The size of a light “formalin band” region, visible in T1 weighted images, was compared to a mathematical model of diffusive mass transfer of formalin into the brain. T1 relaxation, T2 relaxation, and PD all decreased, in both gray and white matter, as formalin fixation progressed. The ADC remained more or less constant. The location of the inner boundary of the formalin band followed a time course consistent with the steepest formalin concentration gradient in the mathematical model. Based on the diffusion model, the brain is not completely saturated in formalin until after 14.8 weeks of formalin immersion and, based on the observed changes in T1, T2, and PD, fixation is not complete until after 5.4 weeks. During fixation, the ongoing attenuation of T1 relaxation, T2 relaxation, and PD must be taken into consideration when performing postmortem MRI studies. Magn Reson Med 54:324–332, 2005. © 2005 Wiley‐Liss, Inc.
Single‐shot 3D imaging techniques improve arterial spin labeling perfusion measurements
Authors: Günther Matthias , Oshio Koichi , Feinberg David A. 
Published: July 2005

AbstractArterial spin labeling (ASL) can be used to measure perfusion without the use of contrast agents. Due to the small volume fraction of blood vessels compared to tissue in the human brain (typ. 3–5%) ASL techniques have an intrinsically low signal‐to‐noise ratio (SNR). In this publication, evidence is presented that the SNR can be improved by using arterial spin labeling in combination with single‐shot 3D readout techniques. Specifically, a single‐shot 3D‐GRASE sequence is presented, which yields a 2.8‐fold increase in SNR compared to 2D EPI at the same nominal resolution. Up to 18 slices can be acquired in 2 min with an SNR of 10 or more for gray matter perfusion. A method is proposed to increase the reliability of perfusion quantification using QUIPSS II derivates by acquiring low‐resolution maps of the bolus arrival time, which allows differentiation between lack of perfusion and delayed arrival of the labeled blood. For arterial spin labeling, single‐shot 3D imaging techniques are optimal in terms of efficiency and might prove beneficial to improve reliability of perfusion quantitation in a clinical setup. Magn Reson Med 54:491–498, 2005. © 2005 Wiley‐Liss, Inc.
Transceive surface coil array for magnetic resonance imaging of the human brain at 4 T
Authors: Pinkerton Robert G. , Barberi Enzo A. , Menon Ravi S. 
Published: July 2005

AbstractAs the static magnetic field strength used in human magnetic resonance imaging increases, the wavelength of the corresponding radiofrequency field becomes comparable to the dimensions of the coil and volume of interest. The dielectric resonance effects that arise in this full wavelength regime may be partially compensated for through the use of surface coils. A novel high‐field (4 T) transceive surface coil array is presented that allows arbitrary surface coil placement and size while maintaining the ability to independently transmit and/or receive through conventional 50‐Ω power amplifiers and preamplifiers, respectively. A ninefold signal‐to‐noise ratio (SNR) increase is shown in close proximity to the transceive array and there is an overall 38% increase throughout the entire brain volume in comparison to the standard hybrid birdcage coil. Furthermore, the ability to independently transmit and receive through each surface coil within this array enables transmit and/or receive‐only fast parallel imaging techniques to be employed while maintaining the increased SNR sensitivity inherent to surface coil designs. Magn Reson Med 54:499–503, 2005. © 2005 Wiley‐Liss, Inc.
Adaptation in the rodent olfactory bulb measured by fMRI
Authors: Schafer James R. , Kida Ikuhiro , Rothman Douglas L. , Hyder Fahmeed , Xu Fuqiang 
Published: July 2005

AbstractEffective evaluation of the odor environment necessitates the ability to attenuate responses to potent background odors in favor of novel and less robust stimuli. Olfactory receptor neuron studies suggest that some of this adaptation takes place in the primary sensory neurons, but the more extensive adaptation seen in higher cortical areas implies the involvement of additional neural mechanisms. At 7.0 T, high‐resolution fMRI was used to assess the response of the rodent olfactory bulb, the most peripheral cortical structure involved in olfactory processing, to a variety of odor stimuli. The results suggest that there are additional regulatory mechanisms in the olfactory bulb that result in greater adaptation in deeper areas than that seen in sensory receptors alone and that the resultant adaptation is positively affected by increasing stimulus duration and concentration and decreasing recovery time. The implications of these findings for the integration of peripheral input with perception are discussed. Magn Reson Med 54:443–448, 2005. © 2005 Wiley‐Liss, Inc.
Testing the three‐pool white matter model adapted for use with T2 relaxometry
Authors: Andrews Trevor , Lancaster Jack L. , Dodd Stephen J. , Contreras‐Sesvold Carmen , Fox Peter T. 
Published: July 2005

AbstractA three‐pool model was used to improve white‐matter T2 relaxometry in low signal‐to‐noise (SNR) data. To verify the model very high SNR T2 relaxometry experiments were performed on myelinated tissue samples and three‐pool fractions were consistently found. Relaxation curves based on the in vitro results were simulated with multiple SNRs and fit using the three‐pool model and three less constraining nonnegative least squares‐based methods. All methods performed well with noiseless data. At lower SNR values the three‐pool model was superior, primarily due to the fact that the other methods often could not unambiguously calculate pool fractions. Magn Reson Med 54:449–454, 2005. © 2005 Wiley‐Liss, Inc.
Determination of dielectric and calorimetric properties in the cure reaction of two thermosets by dielectric analysis and differential scanning calorimetry
Authors: Núñez Lisardo , Gómez‐Barreiro S , Gracia‐Fernández CA 
Published: July 2005

AbstractDielectric analysis and differential scanning calorimetry were used to study the cure reaction of an epoxy resin (the diglycidyl ether of bisphenol A (DGEBA) (n = 0)) and two curing agents, ie 1,2‐diamine cyclohexane (1,2‐DCH) and m‐xylylenediamine (m‐XDA). Various dielectric properties, such as the relaxed permittivity, unrelaxed permittivity and dipole strength, were determined as a function of the curing time, temperature and conversion. The dielectric curing properties observed were related to geometric and energetic aspects of the samples. Analysis of the results shows that the relaxed permittivity and dipole strength are higher for the system DGEBA (n = 0)/1,2‐DCH than for the system DGEBA (n = 0)/m‐XDA. Copyright © 2005 Society of Chemical Industry
Effect of functional groups of modified polyolefins on the structure and properties of their composites with lamellar silicates
Authors: Passaglia Elisa , Sulcis Roberta , Ciardelli Francesco , Malvaldi Marco , Narducci Piero 
Published: July 2005

AbstractThe melt mixing of functionalized polyolefins with a surface‐modified layered silicate (montmorillonite) was investigated as an approach to prepare the corresponding micro/nanocomposites. The effect of the diethyl succinate groups, derived from the grafting of diethyl maleate (DEM) onto the polyolefins, on compatibility with an inorganic filler and the dispersion in a hydrophobic matrix was extensively investigated. In order to avoid possible interference by polymer multiphase morphology, the amorphous poly(propylene‐ran‐ethylene) (EPM) (70/30, wt/wt), functionalized with DEM (EPM‐graft‐DEM), was used in melt mixing with alkyl‐ammonium‐salt‐modified montmorillonite at different weight ratios by using a Brabender mixer. Materials with a nanoscale dispersion of the inorganic phase, as revealed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, were obtained. Specific interactions, involving the carbonyl groups of the polyolefin functional groups and the polar sites on the filler surface, appeared to assist intercalation and/or exfoliation of the layered system. Similar results were obtained by starting with an unfunctionalized EPM and by performing the grafting reaction with DEM during melt mixing according to a one‐step simplified procedure. Copyright © 2005 Society of Chemical Industry
Arenesulfonyl iodides: The third universal class of functional initiators for the metal‐catalyzed living radical polymerization of methacrylates and styrenes
Authors: Percec Virgil , Grigoras Cristian 
Published: July 2005

AbstractThe metal‐catalyzed living radical polymerization of methyl methacrylate and styrene initiated with freshly prepared p‐toluenesulfonyl iodide (TsI) and catalyzed with CuX/2,2′‐bipyridine (bpy), where X is Cl, Br, or I, and various self‐regulated copper‐based catalytic systems, such as copper/bpy, copper(I) oxide/bpy, copper(I) sulfide/bpy, copper(I) selenide/bpy, and copper(I) telluride/bpy, is reported. The exchange of CI into CBr and CCl takes place when the living radical polymerization of methyl methacrylate is catalyzed by copper(I) bromide/bpy and copper(I) chloride/bpy, respectively. Therefore, the use of the TsI initiator facilitates the synthesis, starting from a single initiator, of poly(methyl methacrylate) containing CI, CBr, and CCl chain ends. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3920–3931, 2005
Resistance in the mosquito, Culex quinquefasciatus, and possible mechanisms for resistance
Authors: Xu Qiang , Liu Huqi , Zhang Lee , Liu Nannan 
Published: July 2005

AbstractTwo mosquito strains of Culex quinquefasciatus (Say), MAmCqG0 and HAmCqG0, were collected from Mobile and Huntsville, Alabama, respectively. MAmCqG0 and HAmCqG0 were further selected in the laboratory with permethrin for one and three generations, respectively. The levels of resistance to permethrin in MAmCqG1 (after one‐generation selection) and HAmCqG3 (after three‐generation selection) increased rapidly. Resistance to permethrin in MAmCqG1 and HAmCqG3 was partially suppressed by piperonyl butoxide (PBO), S,S,S‐tributylphosphorotrithioate (DEF) and diethyl maleate (DEM), inhibitors of cytochrome P450 monooxygenases, hydrolases and glutathione S‐transferases (GST), respectively, suggesting these three enzyme families are important in conferring permethrin resistance in both strains. A substitution of leucine to phenylalanine (L to F) resulting from a single nucleotide polymorphism (SNP), termed the kdr mutation, in the para‐homologous sodium channel gene has been reported as a very common mutation associated with pyrethroid resistance of insects. A 341‐bp sodium channel gene fragment, where the kdr mutation resides, was generated by PCR from genomic DNAs of Cx. quinquefasciatus strains. We found that the kdr mutation was present in both permethrin‐selected and unselected HAmCq and MAmCq mosquito populations, suggesting that the kdr mutation plays the role in permethrin resistance. There was no significant change in the frequency and heterozygosity of the A to T SNP for the kdr allele between permethrin‐selected and unselected MAmCq and HAmCq mosquitoes, indicating that other mechanisms are involved in the evolution of resistance in mosquitoes selected by permethrin in the laboratory. Copyright © 2005 Society of Chemical Industry
Horizontal gene transfer of atrazine‐degrading genes (atz) from Agrobacterium tumefaciens St96‐4 pADP1::Tn5 to bacteria of maize‐cultivated soil
Authors: Devers Marion , Henry Sonia , Hartmann Alain , Martin‐Laurent Fabrice 
Published: July 2005

AbstractThe plasmid pADP1::Tn5 derived from pADP1[Atr+] carrying a Tn5 transposon conferring kanamycin and streptomycin resistances was constructed and introduced in Agrobacterium tumefaciens St96‐4. This genetically modified strain was inoculated (∼108 cfu g−1) in potted soils planted with maize and treated or not with atrazine (1.5 mg kg−1). Bulk and maize rhizosphere soils were sampled 39 days after planting to look for soil indigenous bacteria that had acquired pADP1::Tn5. Four transconjugants were isolated from four different soil samples. The estimated transfer frequency of pADP1::Tn5 was 10−4 per donor. Maize rhizosphere and atrazine treatment had no obvious effect on pADP1::Tn5 transfer frequency. The sequencing of the 16S rDNA sequences of the transconjugants revealed that they were almost identical and highly similar to that of Variovorax spp (97%). In addition, their characterization suggested that the atzA and atzB genes had been transferred from pADP1::Tn5 to the bacterial chromosome in two of the four transconjugants. These data suggest that the atz degrading genes are horizontally transferred in soil and possibly subjected to gene rearrangement. Copyright © 2005 Society of Chemical Industry
Carbon nanowires made on diamond surface by focused ion beam
Authors: Zaitsev Alexander M. 
Published: July 2005

AbstractConductive carbon nanowires were made on the polished surface of a single crystal CVD diamond by 30 keV Ga+ ion beam focused to 20 nm. Measurements of conductance of the as‐irradiated nanowires and those annealed at temperature 1400 °C revealed the onset of the ion‐induced conductance to be of 2 × 1015 cm–2. Short nanowires (sub‐micron length) irradiated with subthreshold doses from 5 × 1014 cm–2 to 3 × 1015 cm–2 exhibited unusually high conductivity of 105 Ω–1 cm–1 well exceeding the conductivity of bulk graphite and comparable with that of metals. Tentative explanation of the effect is formation of chains of highly conductive carbon nanorods along 〈100〉 direction in diamond lattice. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The evolutionary ecology of masting: does the environmental prediction hypothesis also have a role in mesic temperate forests?
Authors: Piovesan Gianluca , Adams Jonathan M. 
Published: July 2005

AbstractThe evolutionary advantages of mast seeding in mesic temperate forests are reviewed with reference to the whole plant's lifecycle. The aim of this article is to give attention to the environmental prediction hypothesis as an evolutionary aspect of closed‐forest dynamics that need to be tested in field studies and modelling. It is suggested that the year after a period of water stress (or other suboptimal conditions for growth) trees respond with high seed production. Due to an understory environment favorable for prolific establishment of seedlings (i.e., more light at the forest floor) this may give rise to a pulse of regeneration. Thus, understanding masting may require a multi‐faceted approach including the study of the ecology of the trees themselves beyond pollination and seed predation, and including gap ecology and patch dynamics with special attention to patterns of forest regeneration.
Regional variability in the trophic requirements of shelf sea fisheries in the Northeast Atlantic, 1973–2000
Authors: Heath Michael R. 
Published: July 2005

Abstract
Hydrographic, plankton, benthos, fisheries landings, and fish diet data from shelf sea areas in the Northeast Atlantic have been combined into an analysis of the foodweb structure and secondary production requirements of regional fisheries. Fish landings from the Baltic and North Sea are shown to be taken from a lower trophic level and are shown to be overall more planktivorous than those from shelf edge regions. The secondary production required per unit of landed fish from the North Sea was approximately half that for landings from the southwest approaches to the UK, referred to as the Celtic Seas, where zooplankton production accounted for only a small fraction of the secondary production demands of the fisheries. In the North Sea, variability in zooplankton production seems to have exerted a bottom-up effect on fish production, which in turn has exerted a top-down effect on the benthos. Conversely, Celtic Seas benthos production has been a bottom-up driver of fish production, which seems to have been independent of variability in plankton production. Thus, climate and fishing pressures can be expected to influence these regional fisheries in very different ways. Overall, the results indicate very strong spatial patterns in the fish foodweb structure and function, which will be important considerations in the establishment of regional management plans for fisheries.
The emerging role of climate in post-smolt growth of Atlantic salmon
Authors: Friedland Kevin D. , Chaput Gerald , MacLean Julian C. 
Published: July 2005

Abstract
Though it is well established that mortality during the post-smolt year is critical in shaping recruitment patterns in Atlantic salmon (Salmo salar L.), the controlling mechanism for North Atlantic stocks remains elusive. The emerging paradigm is based on relationships between survival and ocean thermal conditions during the early marine phase. The survival of post-smolts from both Europe and North America has been correlated to sea surface temperature conditions during their first month at sea. In addition, data for European fish support the hypothesis that growth mediates survival during that time. Thus, the working model for a salmon recruitment mechanism is analogous to those proposed for other fish species. We present growth data for two stocks, the Girnock Burn, which is a tributary to the River Dee, Scotland, and the Margaree River, Canada. Circuli spacing data for Girnock Burn fish suggest post-smolt growth is negatively correlated with temperature in the migration corridors during the first months at sea, while post-smolt growth of Margaree fish appears to be positively correlated with temperature. Growth is either patterned by a physiological response to an optimal temperature, or is co-varying with some ecosystem effect on growth, and the growth response might affect mortality and maturation of the stocks.
Co‐integrating currencies and yield differentials
Authors: Inci Ahmet Can 
Published: July 2005

AbstractThis study investigates the relationship between currencies and interest rates of different maturity horizons. The real exchange rate is found to depend both on short‐term real domestic and foreign interest rate difference and on long‐term real domestic and foreign interest rate difference. Co‐integrating regressions of contemporaneous currency rates generate negative and significant coefficients for long‐term rate differentials, consistent with uncovered interest parity. Therefore, the expectations hypothesis holds for long horizons. On the other hand, positive coefficients for real short‐term interest rate differentials reveal the forward premium puzzle: the failure of uncovered interest parity for short‐horizons. Results are partly driven by the very different risk characteristics of short‐term bonds and foreign bonds.
Recurrent events on a Quaternary fault recorded in the mineralogy and micromorphology of a weathering profile, Yangsan Fault System, Korea
Authors: Jeong Gi Young , Cheong Chang-Sik 
Published: July 2005

AbstractRecurrence characteristics of a Quaternary fault are generally investigated on the basis of field properties that are rapidly degraded by chemical weathering and erosion in warm humid climates. Here we show that in intense weathering environments, mineralogical and micromorphological investigations are valuable in paleoseismological reconstruction. A weathering profile developed in Late Quaternary marine terrace deposits along the southeastern coast of the Korean Peninsula was disturbed by tectonic movement that appears to be a simple one-time reverse faulting event based on field observations. A comparative analysis of the mineralogy, micromorphology, and chemistry of the weathering profile and fault gouge, however, reveals that both the microfissures in the deformed weathering profile and larger void spaces along the fault plane were filled with multi-stage accumulations of illuvial clay and silt minerals of detrital origin, suggesting a repetition of fissuring and subsequent sealing in the weathering profile as it underwent continuous mineralogical transformation and particle translocation. We reconstruct a sequence of multiple faulting events unrecognized in previous field surveys, which requires revision of the view that the Korean Peninsula was tectonically stable, during the Late Quaternary.