bluuebunny/crossref_metadata_2025_split huggingface dataset:
An adjustable adiabatic pulse for selective population inversion
Authors: Mitschang Lorenz 
Published: April 2005

AbstractA new adiabatic inversion pulse and its design principles are presented. An analytical expression in the pulse length, inversion bandwidth, inversion efficiency, peak RF amplitude, and width of the transition region is derived and validated. Accordingly, the pulse shape can be adapted to achieve a specified inversion performance. Adjusted for broadband application, population can be inverted band selectively, rather independently of spatial RF field inhomogeneities, and with significantly reduced peak RF amplitude in comparison with the well‐known hyperbolic secant adiabatic pulse. Magn Reson Med 53:1217–1222, 2005. © 2005 Wiley‐Liss, Inc.
Quantification of resting myocardial blood flow in a pig model of acute ischemia based on first‐pass MRI
Authors: Schmitt Melanie , Horstick Georg , Petersen Steffen E. , Karg Andrea , Hoffmann Nico , Gumbrich Thorsten , Abegunewardene Nico , Schreiber Wolfgang G. 
Published: April 2005

AbstractQualitative and semiquantitative contrast‐enhanced (CE) dynamic perfusion MRI techniques are established as noninvasive diagnostic means of assessing coronary artery disease. However, to date quantification of myocardial blood flow (MBF) has not reached the same acceptance as MBF quantification with nuclear techniques. To validate quantification of MBF at rest using the extracellular contrast agent (CA) Gd‐DTPA, we performed an animal study in a pig model of acute myocardial ischemia. We quantified MBF from MRI data with a mathematical model (MMID4) of the underlying vasculature. These MBF results were subsequently compared with the results from fluorescent microspheres. The study showed a correlation of r = 0.66 between MBF estimates obtained with MRI and those obtained with fluorescent microspheres. The correlation for ischemic and nonischemic myocardium was r = 0.86 and r = 0.47, respectively. In conclusion, quantification of resting MBF using MMID4 is a valid method under conditions of acute myocardial ischemia. Magn Reson Med 53:1223–1227, 2005. © 2005 Wiley‐Liss, Inc.
Hexagonal zero mode TEM coil: A single‐channel coil design for imaging multiple small animals
Authors: Lazovic Jelena , Stojkovic Dragan S. , Collins Christopher M. , Yang Qing X. , Vaughan J. Thomas , Smith Michael B. 
Published: April 2005

AbstractA novel hexagonal coil design for simultaneous imaging of multiple small animals is presented. The design is based on a coaxial cavity and utilizes the magnetic field formed between two coaxial conductors with hexagonal cross‐sections. An analytical solution describing the B1 field between conductors of the hexagonal coil was found from the Biot‐Savart law. Both experimental results and analytical calculations showed a variation in the B1 field within the imaging region of less than 10%. Numerical calculations predicted ∼35% improvement in B1 field homogeneity with the hexagonal coil design compared to a cylindrical coaxial cavity design. The experimentally‐measured signal‐to‐noise ratio (SNR) of the hexagonal coil loaded with six 50‐mM phantoms was only 4–5% lower than that of a single parallel plate resonator loaded with one phantom. In vivo spin‐echo (SE) images of six 7‐day‐old rat pups acquired simultaneously demonstrated sufficient SNR for microimaging. The construction scheme of the coil, simple methods for tuning and matching, and an anesthesia device and animal holder designed for the coil are described. The hexagonal coil design utilizes a single receiver and allows for simultaneous imaging of six small animals with no significant compromise in SNR. Magn Reson Med 53:1150–1157, 2005. © 2005 Wiley‐Liss, Inc.
Free‐breathing renal magnetic resonance angiography with steady‐state free‐precession and slab‐selective spin inversion combined with radial k‐space sampling and water‐selective excitation
Authors: Katoh Marcus , Spuentrup Elmar , Stuber Matthias , Hoogeveen Romhild , Günther Rolf W. , Buecker Arno 
Published: April 2005

AbstractThe impact of radial k‐space sampling and water‐selective excitation on a novel navigator‐gated cardiac‐triggered slab‐selective inversion prepared 3D steady‐state free‐precession (SSFP) renal MR angiography (MRA) sequence was investigated. Renal MRA was performed on a 1.5‐T MR system using three inversion prepared SSFP approaches: Cartesian (TR/TE: 5.7/2.8 ms, FA: 85°), radial (TR/TE: 5.5/2.7 ms, FA: 85°) SSFP, and radial SSFP combined with water‐selective excitation (TR/TE: 9.9/4.9 ms, FA: 85°). Radial data acquisition lead to significantly reduced motion artifacts (P < 0.05). SNR and CNR were best using Cartesian SSFP (P < 0.05). Vessel sharpness and vessel length were comparable in all sequences. The addition of a water‐selective excitation could not improve image quality. In conclusion, radial k‐space sampling reduces motion artifacts significantly in slab‐selective inversion prepared renal MRA, while SNR and CNR are decreased. The addition of water‐selective excitation could not improve the lower CNR in radial scanning. Magn Reson Med 53:1228–1233, 2005. © 2005 Wiley‐Liss, Inc.
Reliability estimation of grouped functional imaging data using penalized maximum likelihood
Authors: Gullapalli Rao P. , Maitra Ranjan , Roys Steve , Smith Gerald , Alon Gad , Greenspan Joel 
Published: April 2005

AbstractWe analyzed grouped fMRI data and developed a reliability analysis for such data using the method of penalized maximum likelihood (ML). Specifically, this technique was applied to a somatosensory paradigm that used a mechanical probe to provide noxious stimuli to the foot, and a paradigm consisting of four levels of graded peripheral neuromuscular electrical stimulation (NMES). In each case, reliability maps of activation were generated. Receiver operating characteristic (ROC) curves were constructed in the case of the graded NMES paradigm for each level of stimulation, which revealed an increase in the specificity of activation with increasing stimulation levels. In addition, penalized ML was used to determine whether the grouped reliability maps obtained from one stimulus level were significantly different from those obtained at other levels. The results show a significant difference (P< 0.01) in the reliability of activation from one stimulation level to the next. These results are in agreement with those obtained using generalized linear modeling (GLM). While the reliability maps generated are not directly comparable, they are qualitatively similar to those obtained by controlling the expected false discovery rate (FDR). The proposed methodology can be used to objectively compare activation maps between groups, as well as to perform reliability assessments. Furthermore, this method potentially can be used to assess the longitudinal effect of treatment therapies within a group. Magn Reson Med 53:1126–1134, 2005. © 2005 Wiley‐Liss, Inc.
Positive contrast magnetic resonance imaging of cells labeled with magnetic nanoparticles
Authors: Cunningham Charles H. , Arai Takayasu , Yang Phillip C. , McConnell Michael V. , Pauly John M. , Conolly Steven M. 
Published: April 2005

AbstractContrast agents incorporating superparamagnetic iron‐oxide nanoparticles have shown promise as a means to visualize labeled cells using MRI. Labeled cells cause significant signal dephasing due to the magnetic field inhomogeneity induced in water molecules near the cell. With the resulting signal void as the means for detection, the particles behave as a negative contrast agent, which can suffer from partial‐volume effects. In this paper, a new method is described for imaging labeled cells with positive contrast. Spectrally selective RF pulses are used to excite and refocus the off‐resonance water surrounding the labeled cells so that only the fluid and tissue immediately adjacent to the labeled cells are visible in the image. Phantom, in vitro, and in vivo experiments show the feasibility of the new method. A significant linear correlation (r = 0.87, P < 0.005) between the estimated number of cells and the signal was observed. Magn Reson Med 53:999–1005, 2005. © 2005 Wiley‐Liss, Inc.
Sequence design for magnetic resonance spectroscopic imaging of prostate cancer at 3 T
Authors: Cunningham Charles H. , Vigneron Daniel B. , Marjanska Malgorzata , Chen Albert P. , Xu Duan , Hurd Ralph E. , Kurhanewicz John , Garwood Michael , Pauly John M. 
Published: April 2005

AbstractMagnetic resonance spectroscopic imaging (MRSI) has proven to be a powerful tool for the metabolic characterization of prostate cancer in patients before and following therapy. The metabolites that are of particular interest are citrate and choline because an increased choline‐to‐citrate ratio can be used as a marker for cancer. High‐field systems offer the advantage of improved spectral resolution as well as increased magnetization. Initial attempts at extending MRSI methods to 3 T have been confounded by the J‐modulation of the citrate resonances. A new pulse sequence is presented that controls the J‐modulation of citrate at 3 T such that citrate is upright, with high amplitude, at a practical echo time. The design of short (14 ms) spectral–spatial refocusing pulses and trains of nonselective refocusing pulses are described. Phantom studies and simulations showed that upright citrate with negligible sidebands is observed at an echo time of 85 ms. Studies in a human subject verified that this behavior is reproduced in vivo and demonstrated that the water and lipid suppression of the new pulse sequence are sufficient for application in prostate cancer patients. Magn Reson Med 53:1033–1039, 2005. © 2005 Wiley‐Liss, Inc.
Consequences of liquefied natural gas marine incidents
Authors: Pitblado R. M. , Baik J. , Hughes G. J. , Ferro C. , Shaw S. J. 
Published: April 2005

AbstractThe liquefied natural gas industry in the United States is currently facing challenges in obtaining approvals for new receiving terminals. A factor of concern at public meetings relates to the potential hazards associated with marine transport accidents or terrorist events. The purpose of this study is to develop a range of well‐conceived maximum credible failure cases from accidental or terrorism causes and to predict hazard zones using a well‐validated model. Hazard zones that are presented in this paper tend to fall below many of the values previously quoted. Although additional experimental trials may be warranted, current results are of sufficient confidence to draw valid conclusions. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
Feature Article: Thermodynamic properties from ab‐initio calculations: New theoretical developments, and applications to various materials systems
Authors: Fähnle Manfred , Drautz Ralf , Lechermann Frank , Singer Reinhard , Diaz‐Ortiz Alejandro , Dosch Helmut 
Published: April 2005

AbstractThe cover picture from the Feature Article [1] depicts the calculated landscape of lowest formation energies for the ternary compound system Ni–Fe–Al. The figure shows for each composition the difference in the formation energy (in meV/atom) for the respective homogeneous configuration with lowest energy on the bcc and the fcc parent lattice. The phases on the fcc lattice dominate the Ni‐ and Al‐rich regions of the Gibbs triangle.The first author Manfred Fähnle is Professor at the University of Stuttgart and member of the theory group of the department of Prof. Schütz at the Max‐Planck‐Institut für Metallforschung in Stuttgart. In 1980 he was awarded with the Otto‐Hahn medal of the Max‐Planck Society and in 1985 he received the Academy Award for Physics of the University of Göttingen. His present research interests are the static and dynamic properties of bulk and nanostructured magnetic systems, as well as the ab‐initio statistical mechanics of alloys.
Potential energy surface of the reaction of imidazole with peroxynitrite: Density functional theory study
Authors: Gogonea Valentin 
Published: April 2005

AbstractThis article presents a theoretical investigation of the reaction mechanism of imidazole nitration by peroxynitrite using density functional theory calculations. Understanding this reaction mechanism will help in elucidating the mechanism of guanine nitration by peroxynitrite, which is one of the assumed chemical pathways for damaging DNA in cells. This work focuses on the analysis of the potential energy surface (PES) for this reaction in the gas phase. Calculations were carried out using Hartree–Fock (HF) and density functional theory (DFT) Hamiltonians with double‐zeta basis sets ranging from 6‐31G(d) to 6‐31++G(d,p), and the triple‐zeta basis set 6‐311G(d). The computational results reveal that the reaction of imidazole with peroxynitrite in gas phase produces the following species: (i) hydroxide ion and 2‐nitroimidazole, (ii) hydrogen superoxide ion and 2‐nitrosoimidazole, and (iii) water and 2‐nitroimidazolide. The rate‐determining step is the formation of a short‐lived intermediate in which the imidazole C2 carbon is covalently bonded to peroxynitrite nitrogen. Three short‐lived intermediates were found in the reaction path. These intermediates are involved in a proton‐hopping transport from C2 carbon to the terminal oxygen of the OO moiety of peroxynitrite via the nitroso (ON) oxygen. Both HF and DFT calculations (using the Becke3–Lee–Yang–Parr functional) lead to similar reaction paths for proton transport, but the landscape details of the PES for HF and DFT calculations differ. This investigation shows that the reaction of imidazole with peroxynitrite produces essentially the same types of products (nitro‐ and nitroso‐) as observed experimentally in the reaction of guanine with peroxynitrite, which makes the former reaction a good model to study by computation the essential characteristics of the latter reaction. Nevertheless, the computationally determined activation energy for imidazole nitration by peroxynitrite in the gas phase is 84.1 kcal/mol (calculated at the B3LYP/6‐31++G(d,p) level), too large for an enzymatic reaction. Exploratory calculations on imidazole nitration in solution, and on the reaction of 9‐methylguanine with peroxynitrite in the gas phase and solution, show that solvation increases the activation energy for both imidazole and guanine, and that the modest decrease (15 kcal mol−1) in the activation energy, due to the adjacent six member ring of guanine, is counterbalanced by solvation. These results lead to the speculation that proton tunneling may be at the origin of experimentally observed high reaction rate of guanine nitration by peroxynitrite in solution. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Charge distributions in polyacetylene chains containing a positively charged defect
Authors: Monev Valentin , Spassova Milena , Champagne Benoît 
Published: April 2005

AbstractWe present a comparative study of the AIM, CHELPG, GAPT, MK, Mulliken, NPA, and RESP charge distributions associated with a positively charged soliton on increasingly largetrans‐polyacetylene chains, at HF, MP2, and DFT levels of theory. The charge storage in the soliton‐bearing systems is explored in detail, including charge magnitude, charge separation, charge alternation, and chain length effects. The grouping of the charge distributions at a given level of theory, as well as the sensitivity of a given charge distribution to the inclusion of electron correlation in its computation, are investigated using similarity analysis. Several of the charge definitions have been applied for the first time for charged soliton‐bearing systems, and there are substantial differences between the charge distributions for the charged and neutral systems. Thus, AIM charges are no longer one of the largest charge values, the AIM charges can be in counterphase with other definitions, and the GAPT charges for neutral systems are quite different from the GAPT charges for charged systems, e.g., the magnitudes of the GAPT charges are anomalously large and increase with the size of the charged system. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
An analysis of 0+ barbel (Barbus barbus) response to discharge fluctuations in a flume
Authors: Vilizzi Lorenzo , Copp Gordon H. 
Published: April 2005

AbstractWe studied the response in velocity use and time in refuge of 0+ juvenile barbel (Barbus barbus) to an increase in discharge in a flume. Each of five treated and five control fish were observed individually in separate eight‐hour experiments. Observations (trials) were arranged into a hierarchically structured, semi‐randomized sampling schedule consisting of four time levels: phase (4 h) ⊃ period (2 h) ⊃ sub‐period (30 min) ⊃ trial (120 s). Increased discharge caused treated barbel to use higher velocities than control individuals, with individual differences in behaviour present at the various temporal tiers. Individual responses were modelled as either random‐walk or short‐memory processes, and those by treated fish were generally abrupt and permanent, with only one individual showing a gradual and permanent use of the higher velocities. Time in refuge was not affected by increased discharge, except for one fish that sought shelter after intervention. There was a significant relationship for most treated individuals between selection of lower velocities and time in refuge, and most barbel (both treated and control) showed significant deviations of used from mean flume velocities. The potential of the proposed approach to assess memory‐based individual fish responses to discharge and its consequences for (PHABSIM‐oriented) behavioural studies is discussed, and the mosaic of barbel behaviours observed is compared with available laboratory and field studies. Copyright © 2005 John Wiley & Sons, Ltd.
Assessing the effectiveness of enhancement activities in urban streams: I. Habitat responses
Authors: Suren Alastair M. , Riis Tenna , Biggs Barry J. F. , McMurtrie Shelley , Barker Rachel 
Published: April 2005

AbstractEffects of stream enhancement on habitat conditions in five spring‐fed urban streams in Christchurch, New Zealand, were investigated. Stream enhancement consisted of riparian planting at three sites, and riparian planting and channel modifications at two sites, where a concrete dish channel and a timber‐lined channel were removed, and natural banks reinstated. Sites were surveyed prior to enhancement activities and 5 years after, and changes in riparian conditions (composition, horizontal and vertical cover), instream conditions (bank modifications, inorganic and organic material on the streambed), and hydraulic conditions (wetted perimeter, cross‐sectional area, depths and velocities) quantified. Enhanced sites generally had higher marginal vegetation cover, as well as increased overhanging riparian vegetation, reflecting planting of Carex sedges close to the water. Bed sediments changed at some sites, with the greatest change being replacement of a concrete channel with gravel and cobble substrate. Bryophyte cover declined at this site, reflecting loss of stable habitat where these plants grew. Bed sediments changed less at other sites, and cover of fine sediments increased in some enhanced sites, presumably from sediment runoff from nearby residential development. Filamentous algal cover decreased at one stream where shade increased, but increased in another stream where the removal of timber‐lined banks and creation of a large pond decreased shade. Stream enhancement increased variability in velocity at three of the five sites, but overall changes to stream hydraulics were small. Although enhancement activities altered the physical conditions of the streams, major changes occurred only to riparian vegetation and bank conditions. Lack of other major changes to instream physical conditions most likely reflected the limited range of channel morphology alterations undertaken. Moreover, the flat topography of Christchurch and naturally low stream discharge further constrained changes to instream physical conditions from enhancement activities. Sediment inputs from continuing urban development also negated the effects of adding coarse substrates. These over‐arching factors may constrain the success of future stream enhancement projects within Christchurch. Copyright © 2005 John Wiley & Sons, Ltd.
Assessing the effectiveness of enhancement activities in urban streams: II. Responses of invertebrate communities
Authors: Suren Alastair M. , McMurtrie Shelley 
Published: April 2005

AbstractThe effects of habitat enhancement on the invertebrate communities in five urban streams in Christchurch, New Zealand, were investigated. All streams underwent riparian planting, while extensive channel modifications were made at two streams, where a concrete dish channel and a wooden timber‐lined stream were removed and natural banks reinstated. Benthic invertebrates were collected before enhancement and 5 years after from the same locations. Invertebrates were also collected from control sites in each stream in 2001. Desired goals of enhancement activities included increasing the densities of mayflies and caddisflies, and decreasing densities of oligochaetes, snails and midges. Enhancement activities changed riparian vegetation and bank conditions, as well as substrate composition, instream organic matter and variability of instream velocities. Invertebrate communities prior to enhancement were typical of those in urban environments, and dominated by snails (Potamopyrgus, Physa), the amphipod Paracalliope, the hydroptilid caddisfly Oxyethira, oligochaetes and chironomids. Stream enhancement caused only small changes to the invertebrate community, with subtle shifts in overall abundance, species evenness, diversity, and ordination scores. Lack of a consistent strong response by invertebrates to enhancement activities, and continued absence of caddisflies and mayflies from enhanced sites may reflect lack of sufficient change to instream conditions as a result of stream enhancement, colonization bottlenecks for aerial stages of these animals, and the inability of individuals outside the urban watershed to perceive these enhanced ‘islands’ of good habitat. Alternatively, contamination of streambed sediments, excess sedimentation and reduced base flows may be limiting factors precluding successful invertebrate colonization in enhanced sites. These results highlight the importance of setting clear goals and objectives necessary to meet these goals. Enhancement of riparian zones in urban streams may not be adequate to improve benthic invertebrate communities. Identifying over‐arching factors that potentially limit invertebrate communities will enable the enhancement potential of streams to be better assessed, and allow managers to identify sites where recovery of biological communities is possible, and where such recovery is not. Copyright © 2005 John Wiley & Sons, Ltd.
Advances in fluid therapy and the early care of the burn patient
Authors: Pruitt Basil A. 
Published: April 2005

AbstractThe resuscitation and early care of the burn patient has been placed on a more sound physiologic basis as a result of recent studies of the pathologic effects of thermal injury and the clinical application of technological advances. Whichever resuscitation formula is employed, its application should be guided by the patient's response to treatment. The surgeon must preserve vital organ function while taking advantage of compensatory mechanisms to minimize the deleterious effects of both the injury and the therapy. Resuscitation using only balanced salt solution in the first 24 hours, and reserving colloid‐containing fluids for the second 24 hours, is clinically effective in the vast majority of burn patients, but should be altered in terms of volume and composition to meet the particular needs of any given burn patient. Repeated planned monitoring of cardiopulmonary function and of the peripheral circulation is mandatory to achieve maximum survival of unburned tissue and to reduce mortality. Careful fluid management, including daily assessment of fluid balance, is required from the time of admission until the burn wound has healed or been grafted.