bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liver iron concentration evaluated by two magnetic methods: Magnetic resonance imaging and magnetic susceptometry
Authors: Carneiro Antonio Adilton O. , Fernandes Juliana P. , de Araujo Draulio B. , Elias Jorge , Martinelli Ana L. C. , Covas Dimas T. , Zago Marco A. , Ângulo Ivan L. , St. Pierre Timothy. G. , Baffa Oswaldo 
Published: June 2005

AbstractQuantification of liver iron concentration (LIC) is crucial in the management of patients suffering from certain pathologies that can produce iron overload, such as Cooley's anemia and hemochromatosis. All of these patients must control the level of iron deposits in their organs to avoid the toxicity of high LIC, which is potentially lethal. This paper describes experimental protocols for LIC measurement using two magnetic techniques: magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS). MRI proton transverse relaxation rate (R2) and image intensity, evaluated pixel by pixel, were used as indicators of iron load in the tissue. LIC measurement by BLS was performed using an AC superconducting susceptometer system. A group of 23 patients with a large range of iron overload (0.9 to 34.5 mgFe/gdry tissue) was evaluated with both techniques (MRI × BLS). A significant linear correlation (r = 0.89–0.95) was found between the LIC by MRI and by BLS. These results show the feasibility of using two noninvasive methodologies to evaluate liver iron store in a large concentration range. Both methodologies represent an equivalent precision. Magn Reson Med 54:122–128, 2005. © 2005 Wiley‐Liss, Inc.
Nonnvasive assessment of vascular architecture and function during modulated blood oxygenation using susceptibility weighted magnetic resonance imaging
Authors: Rauscher Alexander , Sedlacik Jan , Barth Markus , Haacke E. Mark , R. Reichenbach Jürgen 
Published: June 2005

AbstractSusceptibility weighted imaging (SWI) is a BOLD‐sensitive method for visualizing anatomical features such as small cerebral veins in high detail. The purpose of this study was to evaluate high‐resolution SWI in combination with a modulation of blood oxygenation by breathing of air, carbogen, and oxygen and to directly visualize the effects of changing blood oxygenation on the magnetic field inside and around venous blood vessels. Signal changes associated with the response to carbogen and oxygen breathing were evaluated in different anatomic regions in healthy volunteers and in two patients with brain tumors. In the magnitude images inhalation of carbogen led to significant signal intensity changes ranging from +4.4 ± 1.9% to +9.5 ± 1.4% in gray matter and no significant changes in thalamus, putamen, and white matter. During oxygen breathing mean signal changes were smaller than during carbogen breathing. The method is capable of producing high‐resolution functional maps of BOLD response to carbogen and oxygen breathing as well as high‐resolution images of venous vasculature. Its sensitivity to changes in blood oxygenation was demonstrated by in vivo visualization of the BOLD effect via phase imaging. Magn Reson Med 54:87–95, 2005. © 2005 Wiley‐Liss, Inc.
Reduction of spinning sidebands in proton NMR of human prostate tissue with slow high‐resolution magic angle spinning
Authors: Burns Melissa A. , Taylor Jennifer L. , Wu Chin‐Lee , Zepeda Andrea G. , Bielecki Anthony , Cory David , Cheng Leo L. 
Published: June 2005

AbstractHigh‐resolution magic angle spinning (HRMAS) NMR spectroscopy has proven useful for analyzing intact tissue and permitting correlations to be made between tissue metabolites and disease pathologies. Extending these studies to slow‐spinning methodologies helps protect tissue pathological structures from HRMAS centrifuging damage and may permit the study of larger objects. Spinning sidebands (SSBs), which are produced by slow spinning, must be suppressed to prevent the complication of metabolic spectral regions. In this study human prostate tissues, as well as gel samples of a metabolite mixture solution, were measured with continuous‐wave (CW) water presaturation on a 14.1T spectrometer, with HRMAS spinning rates of 250, 300, 350, 600, and 700 Hz, and 3.0 kHz. Editing the spectra by means of a simple minimum function (Min(A, B, …, N) for N spectra acquired at different but close spinning rates) produced SSB‐free spectra. Statistically significant linear correlations were observed for metabolite concentrations quantified from the Min(A, B, …, N)‐edited spectra generated at low spinning rates, with concentrations measured from the 3 kHz spectra, and also with quantitative pathology. These results indicate the empirical utility of this scheme for analyzing intact tissue, which also may be used as an adjunct tool in pathology for diagnosing disease. Magn Reson Med 54:34–42, 2005. © 2005 Wiley‐Liss, Inc.
In‐plane velocity encoding with coherent steady‐state imaging
Authors: Grinstead John , Sinha Shantanu 
Published: June 2005

AbstractStandard phase‐contrast flow quantification (PC‐FQ) using radiofrequency (RF) spoiled steady‐state (SS) incoherent gradient‐echo sequences have a relatively low signal‐to‐noise ratio (SNR). Unspoiled SS coherent (SSC) gradient‐echo sequences have a higher intrinsic SNR and are T2/T1 weighted so that blood has a relatively large signal compared to other tissues. An SSC sequence that was modified to allow in‐plane velocity encoding is presented. Velocity encoding was achieved by inverting the readout gradients. This offers the benefit that there is no resultant increase in repetition time (TR), which avoids increased sensitivity to off‐resonance artifacts when conventional velocity‐encoding methods using separate velocity‐encoding gradients are extended to SSC sequences. The results of standard PC‐FQ and the new method from in vitro experiments of constant and sinusoidal flow, and in vivo imaging of the carotid artery were compared. Vector field maps and paths obtained from particle‐tracking calculations based on the velocity‐encoded images were used to visualize the velocity data. The technique has the potential to increase the precision of PC‐FQ measurements. Magn Reson Med 54:138–145, 2005. © 2005 Wiley‐Liss, Inc.
1H MRS‐visible lipids accumulate during apoptosis of lymphoma cells in vitro and in vivo
Authors: Schmitz Jonathan E. , Kettunen Mikko I. , Hu De‐En , Brindle Kevin M. 
Published: June 2005

AbstractProton MRS detection of cellular lipid accumulation has been suggested as a noninvasive method for detecting apoptosis or programmed cell death (PCD) in vivo. The spectral changes that have been observed in apoptotic cells include a general increase in lipid signals and a specific increase in the ratio of the lipid methylene‐to‐methyl peak intensities. These changes were investigated here following drug‐induced apoptosis, both in vitro with a murine lymphoma cell line (EL‐4) and in vivo following implantation of these cells to form subcutaneous tumors. Fluorescence microscopy and flow cytometric measurements with a lipophilic dye revealed an accumulation of cytoplasmic lipid droplets in isolated EL‐4 cells undergoing etoposide‐induced apoptosis. 1H MR spectra (both diffusion‐weighted (DW) and unweighted) showed an increase in lipid signals. However, the methylene/methyl peak ratio showed only minimal changes. Localized in vivo spectroscopy of EL‐4 tumors also showed an increase in lipid signals, including a signal from polyunsaturated lipid at 2.8 ppm, after 16–24 h of drug treatment. Again there was no significant change in the methylene/methyl peak ratio. This study confirms that MRS‐detectable lipids accumulate in tumor cells undergoing apoptosis, and therefore may be usable as a marker for the noninvasive detection of tumor cell apoptosis in the clinic. Magn Reson Med 54:43–50, 2005. © 2005 Wiley‐Liss, Inc.
Parallel imaging for NMR microscopy at 14.1 Tesla
Authors: Sutton Bradley P. , Ciobanu Luisa , Zhang Xiaozhong , Webb Andrew 
Published: June 2005

AbstractParallel imaging techniques using arrays of mutually decoupled coils have become standard on almost all clinical imaging systems. Such techniques also have great potential for high‐field magnetic resonance (MR) microscopy, where measurement times are usually long and susceptibility artifacts can be severe. However, it is technically very challenging to design efficient high‐frequency phased arrays for small‐diameter, vertical‐bore magnets, especially since standard decoupling methods, such as impedance mismatched preamplifiers, cannot be easily integrated. A four‐coil phased array was constructed for microimaging at 600 MHz, and sensitivity encoding (SENSE) and generalized autocalibrating partially parallel acquisitions (GRAPPA) reconstructions of spin‐echo and echo‐planar images of the mouse brain were performed to reduce imaging time and susceptibility artifacts, respectively. Magn Reson Med 54:9–13, 2005. © 2005 Wiley‐Liss, Inc.
Quantitative T1ρ and adiabatic Carr–Purcell T2 magnetic resonance imaging of human occipital lobe at 4 T
Authors: Gröhn Heidi I. , Michaeli Shalom , Garwood Michael , Kauppinen Risto A. , Gröhn Olli H. J. 
Published: June 2005

AbstractThe feasibility of performing quantitative T1ρ MRI in human brain at 4 T is shown. T1ρ values obtained from five volunteers were compared with T2 and adiabatic Carr–Purcell (CP) T2 values. Measured relaxation time constants increased in order from T2, CP‐T2, T1ρ both in white and gray matter, demonstrating differential sensitivities of these methods to dipolar interactions and/or proton exchange and diffusion in local microscopic field gradients, which are so‐called dynamic averaging (DA) processes. In occipital lobe, all relaxation time constants were found to be higher in white matter than in gray matter, demonstrating contrast denoted as an “inverse transverse relaxation contrast.” This contrast persisted despite changing the delay between refocusing pulses or changing the magnitude of the spin‐lock field strength, which suggests that it does not originate from DA, as might be induced by the presence of Fe, but rather is related to dipolar interactions in the brain tissue. Magn Reson Med 54:14–19, 2005. © 2005 Wiley‐Liss, Inc.
Miniature self‐contained intravascular magnetic resonance (IVMI) probe for clinical applications
Authors: Blank Aharon , Alexandrowicz Gil , Muchnik Lev , Tidhar Gil , Schneiderman Jacob , Virmani Renu , Golan Erez 
Published: June 2005

AbstractA miniature (1.73 mm in diameter) NMR probe, which contains a magnet and a radiofrequency (RF) coil, is presented. This probe is integrated at the tip of a standard catheter and can be inserted into the human coronary arteries, creating local magnetic fields needed to obtain the NMR signal from the blood vessel walls, without the need for external magnet or RF coils. The basic theory governing the probe performance in terms of signal‐to‐noise‐ratio and contrast parameters is presented, along with measured results from test samples. The NMR signal can be analyzed to obtain tissue contrast parameters such asT1,T2and the diffusion coefficient, which may be used to detect lipid‐rich vulnerable plaques in the coronary arteries. Magn Reson Med 54:105–112, 2005. © 2005 Wiley‐Liss, Inc.
Evolution of the longitudinal magnetization for pulse sequences using a fast spin‐echo readout: Application to fluid‐attenuated inversion‐recovery and double inversion‐recovery sequences
Authors: Meara Simon J. P. , Barker Gareth J. 
Published: June 2005

AbstractThe fast spin‐echo (FSE) sequence is frequently used as a fast data‐readout technique in conjunction with other pulse sequence elements, such as in fluid‐attenuated inversion‐recovery (FLAIR) and double inversion‐recovery (DIR) sequences. In order to implement those pulse sequences, an understanding is required of how the longitudinal magnetization evolves during the FSE part of the sequence. This evolution has been addressed to a certain extent by previous publications, but the DIR literature in particular appears to be replete with approximations to the exact expression for the longitudinal magnetization, and several papers contain errors. Equations are therefore presented here for the evolution of the longitudinal magnetization for a FSE readout. These are then applied to calculate the magnetization available immediately prior to the 90° imaging pulse for the FLAIR‐FSE and DIR‐FSE pulse sequences. Magn Reson Med 54:241–245, 2005. © 2005 Wiley‐Liss, Inc.
Artificial tumor model suitable for monitoring 31P and 13C NMR spectroscopic changes during chemotherapy‐induced apoptosis in human glioma cells
Authors: Mancuso Anthony , Zhu Aizhi , Beardsley Nancy J. , Glickson Jerry D. , Wehrli Suzanne , Pickup Stephen 
Published: June 2005

AbstractAn artificial tumor method was developed to study cells inside the sensitive volume of an NMR spectrometer during growth and apoptosis. The tumor was composed of a 50:50 mixture of tightly packed porous‐collagen and nonporous‐polystyrene microspheres. The porous collagen served as a growth surface for the tumor cells, and the nonporous polystyrene served as a structural support to limit compression of the packed bed during perfusion. The microspheres were held between two porous polyethylene discs that were tightly sealed inside the NMR perfusion chamber. The new method was evaluated with two cell types: a mouse mammary tumor line (EMT6/SF) and a human glioma line (SF188). The results indicate that for both lines, ∼109 metabolically active cells could be sustained for at least 1 week in the 12‐cm3 artificial tumor. Further, cells undergoing chemotherapy‐induced apoptosis (which is known to cause detachment of cells from their surroundings) were retained in the artificial tumor. In preliminary 31P NMR studies, glioma cells treated with temozolomide (TMZ) exhibited reduced phosphocholine (PCh) levels relative to glycerophosphocholine (GPC) and diphosphodiester (DPDE) levels. They also exhibited sharply reduced oxygen consumption and TCA cycle 13C labeling, while they retained glycolytic activity. These metabolic changes are consistent with those that would be expected during mitochondrially‐mediated apoptosis. Magn Reson Med 54:67–78, 2005. © 2005 Wiley‐Liss, Inc.
Fast high‐resolution T1 mapping of the human brain
Authors: Deichmann Ralf 
Published: June 2005

AbstractA sequence for the acquisition of high‐resolution T1 maps, based on magnetization‐prepared multislice fast low‐angle shot (FLASH) imaging, is presented. In contrast to similar methods, no saturation pulses are used, resulting in an increased dynamic range of the relaxation process. Furthermore, it is possible to acquire data during all relaxation delays because only slice‐selective radiofrequency (RF) pulses are used for inversion and excitation. This allows for a reduction of the total acquisition time, or scanning with a reduced bandwidth, which improves the signal‐to‐noise ratio (SNR). The method generates quantitative T1 maps with an in‐plane resolution of 1 mm, slice thickness of 4 mm, and whole‐brain coverage in a clinically acceptable imaging time of about 19 s per slice. It is shown that the use of off‐center RF pulses does not result in imperfect inversion or magnetization transfer (MT) effects. In addition, an improved fitting algorithm based on smoothed flip angle maps is presented and tested successfully. Magn Reson Med 54:20–27, 2005. © 2005 Wiley‐Liss, Inc.
Facility location for an extraterrestrial production/distribution system
Authors: McKendree Thomas L. , Hall Randolph 
Published: June 2005

AbstractThis paper extends traditional production/distribution system analysis to address raw material, factories, and markets located beyond Earth. It explains the eventual advantages of such operations and discusses likely sites in the solar system. It furnishes a typology for production/distribution systems, assessing the fit of each type to space operations. It briefly reviews the physics of orbits. It develops transportation and inventory cost functions for the simplest case of Hohmann trajectories, and for transportation between circular orbits of similar radii using higher‐energy trajectories. These cost functions are used to derive a model of production/distribution system cost, the minimization of which selects an optimal factory location. The paper suggests potential extensions to this work, and concludes with ideas for location research on the novel reaches of extraterrestrial space. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.
Unique catalytic behavior of chromium complexes having halogenated bis(imino)pyridine ligands for ethylene polymerization
Authors: Nakayama Yuushou , Sogo Kenji , Yasuda Hajime , Shiono Takeshi 
Published: June 2005

AbstractReactions of CrCl3(thf)3 with bis(imino)pyridines gave a series of {bis(imino)pyridine}chromium(III) trichloride complexes, {2,6‐(RNCMe)2C5H3N}CrCl3 [R = C6HPr2‐2,6 (1), C6H3Et2‐2,6 (2), C6H3Me2‐2,6 (3), C6H2Me3‐2,4,6 (4), C6H3Me2‐3,5 (5), C6H5 (6), cyclohexyl (7), 2‐methyl‐1‐naphthyl (8), C6H3F2‐2,6 (9), C6H3Br2‐2,6 (10), C6F5 (11)]. Pseudo‐octahedral geometries of 6, 10, and 11 were revealed by X‐ray crystallography. The complexes having bulky substituents such as 1–4 showed high activity for ethylene polymerization in combination with modified methylaluminoxane (MMAO) to give linear polyethylenes. In sharp contrast, the pentafluorophenyl complex 11/modified methylaluminoxane system was found to be moderately active for ethylene homopolymerization to give moderately branched polyethylene with only ethyl branches. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3368–3375, 2005
Hyperbranched polyesters based on polycondensation of 1,3,5‐tris(2‐hydroxyethyl) cyanuric acid and 3,5‐dihydroxybenzoic acid
Authors: Mansour S. H. , Rozik N. N. , Dirnberger K. , Ikladious N. E. 
Published: June 2005

AbstractA series of hyperbranched polyesters was produced by the condensation of the monomer 3,5‐dihydroxybenzoic acid with 1,3,5‐tris(2‐hydroxyethyl) cyanuric acid as a trifunctional central core. The monomer‐to‐core ratio was varied between 3 and 45. The resulting polymers were phenolic‐terminated polyesters. The degree of branching of the polyesters was calculated according to the method described by Fréchet and was found to be in the range of 0.7–0.8. The number‐average molecular weights calculated via 1H NMR spectroscopic degree‐of‐polymerization values are in reasonable agreement with the predicted values derived from the monomer‐to‐core ratio for all prepared polyesters. Thermal and photophysical properties were also studied. Glass‐transition temperatures were determined by differential scanning calorimetry and were found to be relatively independent of the theoretical molar mass. The polyesters were found to be blue emitters, and the solutions exhibited intense fluorescence, with a maximum of 430 nm. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3278–3288, 2005
The effect of insecticide on adipokinetic hormone titre in the insect body
Authors: Kodrík Dalibor , Socha Radomír 
Published: June 2005

AbstractThe effect of an insecticide, permethrin (Ambush 25 EC), on the titre of two adipokinetic hormones in the central nervous system (CNS) and haemolymph of the firebug Pyrrhocoris apterus (L) was tested. Doses of 2.5, 12.5 and 25 ng of the insecticide elicited no significant effect on the titre of the adipokinetic peptides in CNS, but caused their dramatic elevation in the haemolymph of both macropterous and reproductive brachypterous bugs. Changes in diapausing brachypterous bugs were minimal and not significant. Using high‐performance liquid chromatography (HPLC) and competitive ELISA, both adipokinetic peptides of P apterus (Pyrap‐AKH and Peram‐CAH‐II) were identified and quantified in the CNS of all experimental groups. The ratios of the two peptides in the CNS of the bugs used were affected by insecticide treatment, but in all three groups of bugs the Pyrap‐AKH level remained dominant. The insecticide‐treated bugs were compared with those exposed to forced running (shaking) and dark shock. Both factors also acted as stressors and enhanced the titre of adipokinetic peptides in the haemolymph but had no effect on hormone titre in CNS. The results indicate an involvement of adipokinetic peptides in the response of insect to various stressors including insecticides. Copyright © 2005 Society of Chemical Industry
Off‐axis donors in quasi‐two‐dimensional quantum dots with cylindrical symmetry
Authors: Mikhailov I. D. , Marín J. H. , García F. 
Published: June 2005

AbstractWe propose a simple method for calculating the on‐ and off‐axis neutral and negatively charged donors in axially symmetrical quantum dots whose thickness is much smaller than the base diameter. The adiabatic approximation is used to separate the slow in‐plane motion from the rapid transversal displacements. We show that the low‐lying free electron levels can be found by solving a two‐dimensional central force problem with effective potential whose shape strongly depends on the quantum dot profile in radial direction. The energies of the off‐axis neutral and negatively charged donors are calculated by using fractal dimension method. Novel curves and contour plots for the energies of donors confined in quantum disks, lens, pyramids and rings as functions of the base radius and the distance from the axis are presented. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of density functional theory predictions of gas‐phase deprotonation data
Authors: Liptak Matthew D. , Shields George C. 
Published: June 2005

AbstractThe SVWN, BVWN, BP86, BLYP, BPW91, B3P86, B3LYP, B3PW91, B1LYP, mPW1PW, and PBE1PBE density functionals, as implemented in Gaussian 98 and Gaussian 03, were used to calculate ΔG0 and ΔH0 values for 17 deprotonation reactions where the experimental values are accurately known. The PBE1PBE and B3P86 functionals are shown to compute results with accuracy comparable to more computationally intensive compound model chemistries. A rationale for the relative performance of various functionals is explored. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005