bluuebunny/crossref_metadata_2025_split huggingface dataset:
NMR spectroscopic analysis of new spiro‐piperidylrifamycins
Authors: Rubio Eduardo , Merino Isabel , García Ana‐Belén , Cabal María‐Paz , Ribas Cristina , Bayod‐Jasanada Miguel 
Published: January 2005

AbstractNew spiro‐piperidylrifamycin derivatives are presented. These compounds were synthesized from the reaction of 3‐amino‐4‐iminorifamycin S and enantiomerically pure 4‐piperidones, which generate diasteroisomeric rifabutin analogues with a new stereocentre at the spiranic carbon. The 1H and 13C NMR spectra of these new compounds, and also the configuration of the new stereogenic centres, were assigned using 2D NMR spectroscopic techniques. A preliminary study of the 1H and 13C NMR spectra of the starting compounds rifamycin S, 3‐amino‐4‐iminorifamycin S and the related rifabutin was also carried out and as a result, their previously published 13C NMR data were corrected. Copyright © 2005 John Wiley & Sons, Ltd.
Total NMR assignments of new [C7OC7″]‐biflavones from leaves of the limonene–carvone chemotype of Lippia alba (Mill) N. E. Brown
Authors: Barbosa Francisco Geraldo , Lima Mary Anne Sousa , Silveira Edilberto Rocha 
Published: January 2005

AbstractPhytochemical analysis of leaves of the limonene–carvone chemotype of Lippia alba led to the isolation of two biflavonoids with a new structural pattern with an ether linkage: 5,5″‐dihydroxy‐6,4′,6″,3″′,4″′‐pentamethoxy‐[C7OC7″]‐biflavone (1) and 4′,4,5,5″‐tetrahydroxy‐6,6″,3″′‐trimethoxy‐[C7OC7″]‐biflavone (2). Structural elucidation of the new compounds was established on the basis of spectral data, through the use of 1D NMR and several 2D shift correlated NMR pulse sequences (COSY, HMQC, HMBC and NOESY). Copyright © 2005 John Wiley & Sons, Ltd.
Detailed assignments of 1H and 13C NMR spectral data of 13 β‐substituted cycloenones
Authors: Constantino Mauricio Gomes , Júnior Valdemar Lacerda , da Silva Gil Valdo José 
Published: January 2005

AbstractDetailed assignments of 1H and 13C NMR spectral data for 13 β‐substituted cycloenones are reported. The assignments are based on 1D 1H and 13C NMR and on 2D shift‐correlated (1H,13C‐HMQC and HMBC), J‐resolved and COSY and double irradiation experiments. Copyright © 2005 John Wiley & Sons, Ltd.
Reduction of noise in diffusion tensor images using anisotropic smoothing
Authors: Ding Zhaohua , Gore John C. , Anderson Adam W. 
Published: January 2005

AbstractTo improve the accuracy of tissue structural and architectural characterization with diffusion tensor imaging, a novel smoothing technique is developed for reducing noise in diffusion tensor images. The technique extends the traditional anisotropic diffusion filtering method by allowing isotropic smoothing within homogeneous regions and anisotropic smoothing along structure boundaries. This is particularly useful for smoothing diffusion tensor images in which direction information contained in the tensor needs to be restored following noise corruption and preserved around tissue boundaries. The effectiveness of this technique is quantitatively studied with experiments on simulated and human in vivo diffusion tensor data. Illustrative results demonstrate that the anisotropic smoothing technique developed can significantly reduce the impact of noise on the direction as well as anisotropy measures of the diffusion tensor images. Magn Reson Med 53:485–490, 2005. © 2005 Wiley‐Liss, Inc.
Sizing it up: Cellular MRI using micron‐sized iron oxide particles
Authors: Shapiro Erik M. , Skrtic Stanko , Koretsky Alan P. 
Published: January 2005

AbstractThere is rapidly increasing interest in the use of MRI to track cell migration in intact animals. Currently, cell labeling is usually accomplished by endocytosis of nanometer‐sized, dextran‐coated iron oxide particles. The limitations of using nanometer‐sized particles, however, are that millions of particles are required to achieve sufficient contrast, the label can be diluted beyond observability by cell division, and the label is biodegradable. These problems make it difficult to label cells other than macrophages in vivo, and to conduct long‐term engraftment studies. It was recently demonstrated that micron‐sized iron oxide particles (MPIOs) can be taken up by a number of cell types. In this study we examined the MRI properties of single MPIOs with sizes of 0.96, 1.63, 2.79, 4.50, and 5.80 μm. Furthermore, the capacity of cells to endocytose these MPIOs was investigated, and the MRI properties of the labeled cells at 7.0 and 11.7 Tesla were measured as a function of image resolution and echo time (TE). Cells labeled with MPIOs generally contained iron levels of ∼100 pg, which is approximately threefold higher than those obtained with the best strategies to label cells using nanometer‐sized particles. On occasion, some cells had levels as high as ∼400 pg. We demonstrate that these large particles and the cells labeled with them can be detected by spin echo (SE)‐based imaging methods. These measurements indicate that MPIOs should be useful for improving cell tracking by MRI. Magn Reson Med 53:329–338, 2005. Published 2005 Wiley‐Liss, Inc.
Application of partial differential equation‐based inpainting on sensitivity maps
Authors: Huang Feng , Chen Yunmei , Duensing George R. , Akao James , Rubin Andrew , Saylor Charles 
Published: January 2005

AbstractInpainting is an image interpolation method. Partial differential equation (PDE)‐based digital inpainting techniques are finding broad applications. In this paper, PDE‐based inpainting techniques are applied to the field of MR parallel imaging. A novel model and its corresponding numerical method are introduced. This model is then applied to sensitivity maps. Coil sensitivity maps are important for parallel imaging, and they often require extrapolation and hole filling (holes being dark regions of low signal in MR images). These problems can be solved simultaneously by the application of inpainting techniques. Experiments for determining coil sensitivity maps for phantoms and cardiac MR images demonstrate the accuracy of the proposed model. Images generated using sensitivity encoding (SENSE) that utilizes inpainted sensitivity maps, thin‐plate spline (TPS) estimated sensitivity maps, and Gaussian kernel smoothed (GKS) sensitivity maps are compared. From the experimental results, it can be seen that inpainted sensitivity maps produce better results than GKS sensitivity maps. The TPS method generates results similar to those of the inpainting technique but is much more time‐consuming. Magn Reson Med 53:388–397, 2005. © 2005 Wiley‐Liss, Inc.
Interventional magnetic resonance angiography with no strings attached: Wireless active catheter visualization
Authors: Quick Harald H. , Zenge Michael O. , Kuehl Hilmar , Kaiser Gernot , Aker Stephanie , Massing Sandra , Bosk Silke , Ladd Mark E. 
Published: January 2005

AbstractActive instrument visualization strategies for interventional MR angiography (MRA) require vascular instruments to be equipped with some type of radiofrequency (RF) coil or dipole RF antenna for MR signal detection. Such visualization strategies traditionally necessitate a connection to the scanner with either coaxial cable or laser fibers. In order to eliminate any wire connection, RF resonators that inductively couple their signal to MR surface coils were implemented into catheters to enable wireless active instrument visualization. Instrument background to contrast‐to‐noise ratio was systematically investigated as a function of the excitation flip angle. Signal coupling between the catheter RF coil and surface RF coils was evaluated qualitatively and quantitatively as a function of the catheter position and orientation with regard to the static magnetic field B0 and to the surface coils. In vivo evaluation of the instruments was performed in interventional MRA procedures on five pigs under MR guidance. Cartesian and projection reconstruction TrueFISP imaging enabled simultaneous visualization of the instruments and vascular morphology in real time. The implementation of RF resonators enabled robust visualization of the catheter curvature to the very tip. Additionally, the active visualization strategy does not require any wire connection to the scanner and thus does not hamper the interventionalist during the course of an intervention. Magn Reson Med 53:446–455, 2005. © 2005 Wiley‐Liss, Inc.
The interaction between magnetization transfer and blood‐oxygen‐level‐dependent effects
Authors: Zhou Jinyuan , Payen Jean‐Francois , van Zijl Peter C. M. 
Published: January 2005

AbstractLow‐power off‐resonance spin‐echo magnetization transfer (MT) imaging experiments with a long repetition time (TR) were performed on rat brain for a range of arterial PCO2 levels. The measured magnetization transfer ratio decreased with increased arterial PCO2 levels. When performing blood‐oxygen‐level‐dependent (BOLD) functional magnetic resonance imaging (fMRI)‐type data analysis in which signal intensities were normalized to the normocapnic state, the CO2‐based BOLD effect was much stronger with than without saturation. This increased effect is a consequence of the fact that the MT effect reduces the signal intensity in tissue more than in blood, thereby amplifying the contribution of the intravascular BOLD signal change to the overall BOLD effect. The results offer a potential approach to measure absolute cerebral blood volume in vivo and to amplify the BOLD effects for fMRI studies. Magn Reson Med 53:356–366, 2005. © 2005 Wiley‐Liss, Inc.
Quantification of airway diameters and 3D airway tree rendering from dynamic hyperpolarized 3He magnetic resonance imaging
Authors: Lewis Tina A. , Tzeng Yang‐Sheng , McKinstry Erin L. , Tooker Angela C. , Hong Kwansoo , Sun Yanping , Mansour Joey , Handler Zachary , Albert Mitchell S. 
Published: January 2005

AbstractAs another step toward extracting quantitative information from hyperpolarized 3He MRI, airway diameters in humans were measured from projection images and multislice images of the lungs. Values obtained were in good agreement with the Weibel lung morphometry model. The measurement of airway caliber can now be achieved without the use of ionizing radiation. Furthermore, it was demonstrated that 3D airway tree renderings could be constructed from the multislice data. Both the measurement of airway diameters and the rendering of 3D airway information hold promise for the clinical assessment of bronchoconstrictive diseases such as asthma and the associated evaluation of treatment effectiveness. Work is being done to address the uncertainties of the manually intensive methods we have developed. Magn Reson Med 53:474–478, 2005. © 2005 Wiley‐Liss, Inc.
Real‐time display of artifact‐free electroencephalography during functional magnetic resonance imaging and magnetic resonance spectroscopy in an animal model of epilepsy
Authors: Mirsattari Seyed M. , Ives John R. , Bihari Frank , Leung L. Stan , Menon Ravi S. , Bartha Robert 
Published: January 2005

AbstractSimultaneous recording of electroencephalogram (EEG) and functional MRI (fMRI) or MR spectroscopy (MRS) can provide further insight into our understanding of the underlying mechanisms of neurologic disorders. Current technology for simultaneous EEG and MRI recording is limited by extensive postacquisition processing of the data. Real‐time display of artifact‐free EEG recording during fMRI/MRS studies is essential in studies that involve epilepsy to ensure that they address specific EEG features such as epileptic spikes or seizures. By optimizing the EEG recording equipment to maximize the common mode rejection ratio of its amplifiers, a unique EEG system was designed and tested that allowed real‐time display of the artifact‐free EEG during fMRI/MRS in an animal model of epilepsy. Spike recordings were optimized by suppression of the background EEG activity using fast‐acting and easily controlled inhalational anesthesia. Artifact suppression efficiency of 70–100% was achieved following direct subtraction of referentially recorded filtered EEG tracings from active electrodes, which were located in close proximity to each other (over homologous occipital cortices) and a reference electrode. Two independent postacquisition processing tools, independent component analysis and direct subtraction of unfiltered digital EEG data in MATLAB, were used to verify the accuracy of real‐time EEG display. Magn Reson Med 53:456–464, 2005. © 2005 Wiley‐Liss, Inc.
Chemical‐shift‐selective filter for the in vivo detection of J‐coupled metabolites at 3T
Authors: Schulte Rolf F. , Trabesinger Andreas H. , Boesiger Peter 
Published: January 2005

AbstractA chemical‐shift‐selective filter (CSSF) was applied to the detection of J‐coupled metabolites in the human brain. This filter is an acquisition‐based technique that requires the chemical shifts (CS's) of different metabolites, but not their whole multiplet structures, to be resolved. The sequence is based on the 2D constant‐time spin‐echo experiment, which yields pure CS spectra in the indirect dimension. Localization is achieved through point‐resolved spectroscopy (PRESS). The method enables unequivocal detection of glutamate and myo‐inositol, both in vitro and in vivo in the human brain, at 3T. Magn Reson Med 53:275–281, 2005. © 2005 Wiley‐Liss, Inc.
Quantitative breath‐hold monitoring of myocardial gadolinium enhancement using inversion recovery TrueFISP
Authors: Goldfarb James W. , Mathew Sunil T. , Reichek Nathaniel 
Published: January 2005

AbstractThe purpose of this work was to develop and evaluate the accuracy of a breath‐hold IR‐TrueFISP acquisition capable of monitoring gadolinium (Gd) concentrations through T1 measurements in the left ventricular blood pool and segments of the myocardium over an extended duration. Measurements using a phantom were performed to assess the accuracy of the technique. Accurate T1 measurements in the expected range after contrast agent administration were obtained with several theoretical formulations. Accurate T1 values before the administration of the contrast agent were obtained only when the incomplete recovery of magnetization during the delay time (TD) between imaging segments was incorporated into the observed signal intensity calculations. T1 measurements over a 1‐hr time period were performed in four subjects with known myocardial infarctions. In this small study, Gd differences between recent and old myocardial infarctions were observed. Magn Reson Med 53:367–371, 2005. © 2005 Wiley‐Liss, Inc.
Tozer et al. Quantitative Magnetization Transfer Mapping of Bound Protons in Multiple Sclerosis, Magn Reson Med 2003;50:83‐91
Authors: Tofts P.S. , Cercignani M. , Tozer D.J. , Symms M.R. , Davies G.R. , Ramani A. , Barker G.J. 
Published: January 2005

AbstractThe original article to which this Erratum refers was published in Magnetic Resonance in Medicine (2003) 50(1) 83–91.
Reduction of blurring in view angle tilting MRI
Authors: Butts Kim , Pauly John M. , Gold Garry E. 
Published: January 2005

AbstractMagnetic resonance imaging (MRI) in the presence of metallic objects suffers from slice‐selection errors and in‐plane distortions. View angle tilting (VAT) corrects for in‐plane distortions by adding a gradient on the slice‐select axis during readout, but can suffer from image blurring. This work demonstrates that the major source of blurring is a slice profile modulation of the data, and proposes several solutions to prevent such blurring. Multiple high‐bandwidth readouts are demonstrated to reduce the blurring while improving the signal‐to‐noise ratio (SNR) over a single high‐bandwidth readout. Magn Reson Med 53:418–424, 2005. © 2005 Wiley‐Liss, Inc.
Age‐related decline in muscle strength and power output in acid 1–4 α‐glucosidase knockout mice
Authors: Hesselink Reinout P. , Van Kranenburg Gerrit , Wagenmakers Anton J. M. , Van der Vusse Ger J. , Drost Maarten R. 
Published: January 2005

AbstractA hallmark of glycogen storage disease type II, caused by defective α‐glucosidase (AGLU) activity, is a progressive decline in muscle performance. The objective of this study was to determine the relative contribution to this decline in muscle performance of (1) decline in muscle mass; (2) decline in muscle protein content per unit mass; and (3) accumulation of glycogen. To this end, isometric torque and power in AGLU−/− mice at 7, 13, and 20 months were assessed in situ. Power (∼24 mW) and torque (∼2.45 Nmm) did not change with age in control animals, but declined significantly in AGLU−/− mice, in the three age groups. No decline in protein content per unit muscle mass was observed. Muscle atrophy explained one third of the decline in muscle performance; the remaining part was attributed to a decrease in muscle quality—a decrease in mechanical performance per unit muscle mass. Mechanical effects of glycogen inclusions could not fully explain this decrease. Additional factors must therefore play a role. Muscle Nerve, 2005
Co‐morbidity of ‘Clinical Trial’ versus ‘Real‐World’ patients using cardiovascular drugs
Authors: Wieringa Nicolien F. , Vos Rein , Van Der Werf Ger Th. , Van Der Veen Willem Jan , De Graeff Pieter A. 
Published: January 2005

AbstractPurposeTo examine discrepancies between co‐morbidity of patients included in pre‐marketing clinical trials of cardiovascular drugs and patients from daily practice, representing the actual users after marketing, and to investigate the availability of data regarding co‐morbidity in registration files.MethodsData were collected from phase III trials of registration files of 16 drugs, registered in the Netherlands in the period 1985 through 1994 for the indications hypertension, angina pectoris or hypercholesterolemia, and from a general practitioners database. Patients were selected who used drugs from the same therapeutic classes for the same indication as the patients in the pre‐marketing trials. Prevalences of concomitant cardiovascular, endocrine and metabolic diseases were compared between pre‐ and postmarketing populations. Discrepancies were defined as more than 10% difference in prevalences.ResultsData regarding co‐morbidity were present in 13 out of 16 registration files and differed in format of reporting. For all indications, coexisting cardiovascular, endocrine and metabolic diseases were less prevalent in the pre‐marketing populations, except ischemic heart disease, which was more prevalent coexisting with angina pectoris and hypercholesterolemia. Discrepancies were found for hypertensive disease, heart failure, diabetes mellitus and myocardial infarction.ConclusionsPhase III trials testing cardiovascular drugs included patients with concomitant cardiovascular, endocrine and metabolic diseases, but discrepancies were present with patients in daily practice. Development of guidelines for uniform collection and reporting of co‐morbidity data in pre‐marketing trials is recommended, as well as further utilization of data. Copyright © 2000 John Wiley & Sons, Ltd.
Do NHLBI lung function criteria apply to children? A cross‐sectional evaluation of childhood asthma at National Jewish Medical and Research Center, 1999–2002
Authors: Paull Keith , Covar Ronina , Jain Neal , Gelfand Erwin W. , Spahn Joseph D. 
Published: January 2005

AbstractAlthough National Heart Lung Institute (NHLBI) guidelines categorize asthma severity based on spirometry, few studies have evaluated the utility of these spirometric values in grading asthma severity in children. Asthma is thought to be progressive, but little is known about the loss of lung function in childhood. This study sought to determine the spirometric indices in children from 4–18 years of age. Retrospective cross‐sectional analysis was performed on all spirometries done in children at the National Jewish Medical and Research Center from 1999–2002. In total, 2,728 children performed 24,388 measures. The mean ± SD values for forced vital capacity (FVC), forced expired volume in 1 sec (FEV1), FEV1/FVC ratio, and forced expiratory flow (FEF)25–75 were 92.7 ± 16.2, 92.2 ± 18.0, 85.3 ± 9.3, and 78.0 ± 36.5 percent predicted, respectively. Seventy‐seven percent of FEV1 values were ≥ 80%, 18.6% were between 60–80%, and 3.1% were <60% of predicted. FEV1 was highest in 5‐year‐old children; it declined thereafter, reaching a nadir at 11 years, followed by a partial recovery from 12–18 years. Expressed in liters, FEV1 values were lower than expected at every age, with the greatest difference at 18 years. FEV1/FVC ratios declined through childhood, suggesting impaired airway but not lung growth in children with asthma. In conclusion, the majority of asthmatic children attending a tertiary care facility had FEV1 values within normal range. With increasing age, the increase in FEV1 lags behind that of nonasthmatics, so that by 18 years, maximum FEV1 is impaired. The NHLBI FEV1 cutoff values do not appear to accurately stratify pediatric asthma, and no useful FEV1 cutoff could be generated. Pediatr Pulmonol. 2005; 39:311–317. © 2005 Wiley‐Liss, Inc.
Misdiagnosing cystic fibrosis in the era of gene analysis: Case reports
Authors: Moser Chuanpit , Nussbaum Eliezer , Thompson Rohan 
Published: January 2005

AbstractWe present a scenario of how gene analysis plays a confusing role in the diagnosis of cystic fibrosis (CF). One of the two siblings we are presenting here was initially misdiagnosed as having CF, based on the two CF gene mutations identified by gene analysis. A CF gene study on the other sibling years later, however, led to further investigation and eventually to a change of diagnosis. As interesting and important as gene analysis is in CF, one must always look at each patient in the big picture. Included in the picture, in addition to the state‐of‐the‐art genotype, is the phenotype, or (to simplify) the back‐to‐basic clinical manifestations. Pediatr Pulmonol. 2005; 39:379–381. © 2005 Wiley‐Liss, Inc.
Negative thermal expansion in the layered semiconductor TlGaSe2
Authors: Abdullayev N. A. , Mammadov T. G. , Suleymanov R. A. 
Published: January 2005

AbstractThe nature of negative thermal expansion in the layer plane of the layered semiconductor TlGaSe2 has been investigated. It is shown that, in contrast to other crystals with a layered structure in which negative linear expansion is observed, the nature of the negative thermal expansion in TlGaSe2 crystals is due to the large Poisson contraction. The possible explanation of such an effect is discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shot noise and higher current moments in dimensions 2, 3 and 4
Authors: Travěnec I. 
Published: January 2005

AbstractShot noise and higher current moments TM = 〈Tr (t†t)M〉 are studied within the Anderson model of disordered conductors in dimensions d = 2, 3 and 4. Here t denotes a transmission matrix. We calculate the conductance G = T1, shot noise S = T1–T2, Fano factor F = S/G and ratios CM = TM /G, and we show indications that all of them are as good order parameters as the conductance itself. In the limit of infinite system size, two limiting values of and CM are found; the stable one in the metallic regime, and the unstable one, characterizing the critical point for d > 2. We present analytical expressions for both limiting values, together with a compact formula for current cumulants at 3D criticality. Our data confirm also Nazarov's microscopic theory [Phys. Rev. B 52, 4720 (1995)], as we show numerically for special linear combinations of TM. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)