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High-resolution
Terms modified by High-resolution Selected AbstractsHigh-resolution computer simulation of the dynamics of isoelectric focusing of proteinsELECTROPHORESIS, Issue 2 2004Wolfgang Thormann Abstract A dynamic electrophoresis simulator that accepts 150 components and voltage gradients employed in the laboratory was used to provide a detailed description of the focusing process of proteins under conditions that were hitherto inaccessible. High-resolution focusing data of four hemoglobin variants in a convection-free medium are presented for pH 3,10 and pH 5,8 gradients formed with 20 and 40 carrier ampholytes/pH unit, respectively. With 300 V/cm, focusing is shown to occur within 5,10 min, whereas at 600 V/cm separation is predicted to be complete between 2.5 and 5 min. The time interval required for focusing of proteins is demonstrated to be dependent on the input protein charge data and, however less, on the properties of the carrier ampholytes. The simulation data reveal that the number of transient protein boundaries migrating from the two ends of the column towards the focusing positions is equal to the number of sample components. Each protein is being focused via the well-known double-peak approach to equilibrium, a process that is also characteristic for focusing of the carrier ampholytes. The predicted focusing dynamics for the hemoglobin variants in pH 3,10 and pH 5,8 gradients are shown to qualitatively agree well with experimental data obtained by whole-column optical imaging. [source] Fine-scale movements of the swordfish Xiphias gladius in the Southern California BightFISHERIES OCEANOGRAPHY, Issue 4 2010CHUGEY A. SEPULVEDA Abstract This study reports on the fine-scale movements of swordfish (Xiphias gladius) outfitted with pop-off satellite archival transmitters (PSATs) in the Southern California Bight (SCB). PSATs were deployed on basking swordfish using traditional harpoon methods from 2004 to 2006. Transmitters were programmed for short-term deployment (2,90 days) and re-acquired using a signal direction finder. High-resolution (min,1) depth and temperature data from nine swordfish (approximately 45,120 kg) were collected (>193 days). All swordfish displayed diurnal vertical movements similar to those reported for other geographic locations. The dominant diurnal movement pattern entailed swordfish remaining below the thermocline (>68 ± 15 m) during the day and near the surface, within the upper-mixed layer, at night. Collectively, the average daytime depth (±SE) was 273 ± 11 m and the average night depth 31 ± 5 m. Three distinct vertical behaviors were recorded: 35% of the records following a strict diurnal pattern, with the entire day below the thermocline and the entire night near the surface; 52% of the records revealed routine surface-basking events during the day, with an otherwise similar distribution at night; and 13% of the records exhibited surface-oriented activity during the day and night. Surface basking (<3 m during the day) was recorded for eight individuals and occurred on 131 of the 193 days (68% of the dataset). Collectively, surface basking accounted for 8% of the total daytime records. The relevance of these vertical behaviors to SCB fisheries is discussed. [source] High-resolution, monotone solution of the adjoint shallow-water equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2002Brett F. Sanders Abstract A monotone, second-order accurate numerical scheme is presented for solving the differential form of the adjoint shallow-water equations in generalized two-dimensional coordinates. Fluctuation-splitting is utilized to achieve a high-resolution solution of the equations in primitive form. One-step and two-step schemes are presented and shown to achieve solutions of similarly high accuracy in one dimension. However, the two-step method is shown to yield more accurate solutions to problems in which unsteady wave speeds are present. In two dimensions, the two-step scheme is tested in the context of two parameter identification problems, and it is shown to accurately transmit the information needed to identify unknown forcing parameters based on measurements of the system response. The first problem involves the identification of an upstream flood hydrograph based on downstream depth measurements. The second problem involves the identification of a long wave state in the far-field based on near-field depth measurements. Copyright © 2002 John Wiley & Sons, Ltd. [source] Mapping Quantitative Trait Loci for Vertebral Trabecular Bone Volume Fraction and Microarchitecture in Mice,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2004Mary L Bouxsein Abstract BMD, which reflects both cortical and cancellous bone, has been shown to be highly heritable; however, little is known about the specific genetic factors regulating trabecular bone. Genome-wide linkage analysis of vertebral trabecular bone traits in 914 adult female mice from the F2 intercross of C57BL/6J and C3H/HeJ inbred strains revealed a pattern of genetic regulation derived from 13 autosomes, with 5,13 QTLs associated with each of the traits. Ultimately, identification of genes that regulate trabecular bone traits may yield important information regarding mechanisms that regulate mechanical integrity of the skeleton. Introduction: Both cortical and cancellous bone influence the mechanical integrity of the skeleton, with the relative contribution of each varying with skeletal site. Whereas areal BMD, which reflects both cortical and cancellous bone, has been shown to be highly heritable, little is known about the genetic determinants of trabecular bone density and architecture. Materials and Methods: To identify heritable determinants of vertebral trabecular bone traits, we evaluated the fifth lumbar vertebra from 914 adult female mice from the F2 intercross of C57BL/6J (B6) and C3H/HeJ (C3H) progenitor strains. High-resolution ,CT was used to assess total volume (TV), bone volume (BV), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), separation (Tb.Sp), and number (Tb.N) of the trabecular bone in the vertebral body in the progenitors (n = 8/strain) and female B6C3H-F2 progeny (n = 914). Genomic DNA from F2 progeny was screened for 118 PCR-based markers discriminating B6 and C3H alleles on all 19 autosomes. Results and Conclusions: Despite having a slightly larger trabecular bone compartment, C3H progenitors had dramatically lower vertebral trabecular BV/TV (,53%) and Tb.N (,40%) and higher Tb.Sp (71%) compared with B6 progenitors (p < 0.001 for all). Genome-wide quantitative trait analysis revealed a pattern of genetic regulation derived from 13 autosomes, with 5,13 quantitative trait loci (QTLs) associated with each of the vertebral trabecular bone traits, exhibiting adjusted LOD scores ranging from 3.1 to 14.4. The variance explained in the F2 population by each of the individual QTL after adjusting for contributions from other QTLs ranged from 0.8% to 5.9%. Taken together, the QTLs explained 22,33% of the variance of the vertebral traits in the F2 population. In conclusion, we observed a complex pattern of genetic regulation for vertebral trabecular bone volume fraction and microarchitecture using the F2 intercross of the C57BL/6J and C3H/HeJ inbred mouse strains and identified a number of QTLs, some of which are distinct from those that were previously identified for total femoral and vertebral BMD. Identification of genes that regulate trabecular bone traits may ultimately yield important information regarding the mechanisms that regulate the acquisition and maintenance of mechanical integrity of the skeleton. [source] Prednisone Prevents Inducible Atrial Flutter in the Canine Sterile Pericarditis ModelJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2008ROBERT N. GOLDSTEIN M.D. Background: Atrial fibrillation (AF) and atrial flutter (AFL) are common following cardiac surgery and are associated with significant morbidity. We tested the hypothesis that suppression of the inflammatory response with steroids would significantly modify the inducibility of postoperative AF/AFL in the canine sterile pericarditis model. Methods: Twenty-three dogs were studied daily from creation of pericarditis to the fourth postoperative day: 11 dogs were treated with oral prednisone (PRED) starting 2 days preoperatively until the end of the study; 12 dogs were controls (CON). EP testing was performed daily using epicardial electrodes placed at initial surgery. High-resolution (404 sites) epicardial mapping was performed during the terminal study. Baseline and daily CRP levels were obtained in all dogs. Results: Sustained AFL was absent in PRED (0%) versus CON dogs (91%; P < 0.001); AF induced in the early postoperative course in PRED dogs was of very short CL (mean 66 ms). Tissue inflammation was significantly attenuated in PRED dogs. Thresholds were lower in PRED versus CON dogs, significantly so on postoperative day (POD) 3. There was a trend toward lower ERPs in the PRED group at all CLs. CRP levels were markedly reduced in PRED versus CON dogs (peak CRP 78 ± 7 mg/L vs 231 ± 21 mg/L, P < 0.001), and returned to baseline in PRED dogs by POD 4, correlating with a virtual absence of sustained arrhythmia. During open chest mapping studies on POD 4, PRED dogs showed only nonsustained AF/AFL. Conclusions: Prednisone eliminated postoperative AFL, affected all EP parameters studied, and attenuated the inflammatory response associated with pericarditis. [source] Matrix-assisted laser desorption/ionization Fourier transform mass spectrometric analysis of oxygenated triglycerides and phosphatidylcholines in egg tempera paint dosimeters used for environmental monitoring of museum display conditionsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 5 2001Oscar F. van den Brink Abstract Oxidative changes in triacylglycerols and diacylphosphatidylcholines in egg tempera paint strips are used for chemical dosimetry of the quality of the museum environment. High-resolution matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) was used as a rapid method for the determination of the exact elemental composition of the alteration products from diacylphosphatidylcholines and triacylglycerols. Light exposure of the egg tempera paints yields oxygenated diacylphosphatidylcholines and triacylglycerols. In the latter multiple incorporation of oxygen was observed as a recurring mass difference of 15.995, the exact atomic mass of oxygen. Owing to the high resolution of the FTMS data (routinely 20 000 at m/z 1000 in broadband mode), oxidation products with different elemental compositions but identical nominal mass could be distinguished. Products of oxidative cleavage of triacylglycerols were observed in samples exposed for longer times. The relative intensities of the peaks of singly and multiply oxygenated triacylglycerols were used to derive the degree of oxygenation of the egg lipids in the tempera paint dosimeters. The degree of oxygenation was found to be directly related to the light exposure time. Exposure to elevated temperature (60 °C) for a period of 21 days did not lead to oxygenation of the triacylglycerols and diacylphosphatidylcholines. Exposure to NOx and SO2 in the dark greatly increased the degree of oxygenation. Addition of lead- or copper-containing pigments to the egg binding medium (and subsequent storage for 6 months in the dark) led to accelerated conversion of egg lipids to oxidised products. Copyright © 2001 John Wiley & Sons, Ltd. [source] High-resolution stimulated Raman spectroscopy and analysis of the 2,10 overtone symmetric motion of C2H4JOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2009M. Loroño Abstract The high-resolution stimulated Raman spectrum of the 2,10 band located at 1664.16 cm,1 of C2H4 has been reanalyzed, thanks to the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. A total of 191 lines were assigned and fitted as a single band without including perturbations such as Fermi or Coriolis coupling constants. We obtained a global root mean square deviation of 8.5 × 10,3 cm,1. Further investigations are required to include interactions with the ,2 and ,7 + ,10 bands. Copyright © 2009 John Wiley & Sons, Ltd. [source] Microstructure of Nanocrystalline Yttria-Doped Zirconia Thin Films Obtained by Sol,Gel ProcessingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2008Benjamin Butz Nano- and microcrystalline yttria-stabilized zirconia (YSZ) thin films with a dopant concentration of 8.3±0.3 mol% Y2O3 were prepared with a variation in grain size by two orders of magnitude. A sol,gel-based method with consecutive rapid thermal annealing was applied to fabricate YSZ films, resulting in about 400 nm YSZ on sapphire substrates. The average grain sizes were varied between 5 nm and 0.5 ,m by heat treatment in the temperature range of 650°,1350°C for 24 h. High-resolution (HRTEM) and conventional transmission electron microscopy analyses confirmed specimens,irrespective of the thermal treatment,consisting of cubic (c -)ZrO2 grains with nanoscaled tetragonal precipitates coherently embedded in the cubic matrix. Energy-dispersive X-ray spectroscopy and HRTEM on a large number of specimens yielded a homogeneous yttria concentration within the grains and at the grain boundaries with the absence of impurities, i.e. silica at the grain boundaries. [source] Mapping at glomerular resolution: fMRI of rat olfactory bulbMAGNETIC RESONANCE IN MEDICINE, Issue 3 2002Ikuhiro Kida Abstract The rat olfactory bulb contains ,2000 functional units called glomeruli which are used to recognize specific characteristics of odorants. Activity localization of individual glomerulae (,0.002 ,L) has important consequences for understanding mechanisms in olfactory information encoding. High-resolution functional MRI (fMRI) data from the rat olfactory bulb are presented using the blood oxygenation level dependent (BOLD) method at 7 T. Either individual or clusters of fMRI voxels suggestive of activity in the olfactory nerve and glomerular layers were reproducibly detected with repeated 2-min exposures of iso-amyl acetate at spatial resolution of 0.001,0.003 ,L. The importance of glomerular clustering for olfaction and the implications of BOLD mapping with even higher spatial resolution (i.e., ,0.001 ,L voxels) are discussed. High-resolution in vivo mapping of the rat olfactory bulb with fMRI at high magnetic field promises to provide novel data for understanding olfaction. Magn Reson Med 48:570,576, 2002. © 2002 Wiley-Liss, Inc. [source] High-resolution isotropic 3D diffusion tensor imaging of the human brainMAGNETIC RESONANCE IN MEDICINE, Issue 5 2002Xavier Golay Abstract High-resolution cardiac-gated 3D diffusion tensor imaging (3D-DTI) is demonstrated in vivo for several areas of the human brain. Anatomical mapping of subcortical white matter (WM), as well as definition and identification of major WM bundles from the brainstem were performed in humans for the first time using this technique. Improved intrinsic signal-to-noise ratio (SNR) and relatively reduced sensitivity to physiological motion (e.g., brain pulsations) with respect to cardiac-gated multislice acquisition are demonstrated. The advantages and weaknesses of this approach are discussed. Magn Reson Med 47:837,843, 2002. © 2002 Wiley-Liss, Inc. [source] Surfactant protein C gene (SFTPC) mutation-associated lung disease: High-resolution computed tomography (HRCT) findings and its relation to histological analysis,,PEDIATRIC PULMONOLOGY, Issue 10 2010M. Mechri MD Abstract Aim of the Study Determine high-resolution tomography (HRCT) scan characteristics in children with SFTPC mutation and correlate them to histological findings. Patients and Methods This retrospective multicenter study included 15 children (7 females and 8 males) with SFTPC mutations. HRCT scans have been performed in all the children and lung biopsies in 8 children. Results From all signs assessed on initial HRCT scans, ground-glass opacities (n,=,14, 93%) and lung cysts (n,=,6, 40%) were predominant. Interlobular septal thickening (n,=,1, 7%), air space consolidation (n,=,1, 7%), paraseptal emphysema (n,=,2, 13%), and pulmonary nodules (n,=,1, 7%) were also found. Histological analysis revealed accumulation of macrophages in the alveolar lumen, type II pneumocyte hyperplasia, and alveolar septal thickening. Dilatation of the respiratory bronchiole and alveolar duct associated with muscular hyperplasia were also described. Interestingly, lung cysts on HRCT scans were associated with dilatation of terminal bronchioli and alveolar duct in lung biopsies. Conclusion In children with SFTPC mutations, HRCT scan finding was highly correlated to the histological findings and, as such, represent a useful tool to identify patients that may require SFTPC gene sequencing. Pediatr Pulmonol. 2010; 45:1021,1029. © 2010 Wiley-Liss, Inc. [source] Pulmonary interstitial glycogenosis in identical twinsPEDIATRIC PULMONOLOGY, Issue 4 2005W. Onland MD Abstract We present the clinical, radiological, and pathological findings of open lung biopsies from monozygotic prematurely born male twins with respiratory distress at ages 6 and 8 weeks postnatally. Radiological examination showed a reticular nodular interstititial pattern on chest radiography. High-resolution computed tomography (HRCT) revealed ground-glass opacification and thickened interstitial septae in both infants. Lung biopsies showed a similar histology. There was diffuse interstitial thickening of the alveolar septa by mesenchymal cells, without prominent hyperplasia of type 2 pneumocytes, and without airspace exudates. Sections were periodic acid-Schiff (PAS)-positive within the cytoplasm of interstitial cells, indicating the presence of glycogen. Thus the diagnosis of pulmonary interstitial glycogenosis was made. Both infants were treated with glucocorticoids and had a favorable outcome. We speculate that pulmonary interstitial glycogenosis could be a histopathological form of chronic lung disease (CLD) of infancy. Pediatr Pulmonol. © 2005 Wiley-Liss, Inc. [source] Early pulmonary involvement in Niemann-Pick type B disease: Lung lavage is not usefulPEDIATRIC PULMONOLOGY, Issue 2 2005Z.S. Uyan MD Abstract Niemann-Pick disease (NPD) is a rare, autosomal-recessively inherited lipid storage disease which is characterized by intracellular deposition of sphingomyelin in various body tissues. The disease is heterogeneous and classified into six groups. Pulmonary parenchymal involvement may be a feature of several subtypes of NPD, including type B. Progressive pulmonary involvement in NPD type B is a major cause of morbidity and mortality. It is usually diagnosed at older ages. Only a few cases with early pulmonary involvement have been reported. In this report, a patient with NPD type B, hospitalized with the diagnosis of pneumonia at age 3 months, is presented. Following treatment for pneumonia, she continued to have persistent respiratory symptoms and became oxygen-dependent. High-resolution computed tomography of the chest revealed diffuse interstitial changes. During follow-up, the patient developed hepatosplenomegaly. Lung, liver, and bone marrow biopsies showed characteristic findings for NPD. Biochemical studies also confirmed the diagnosis, and the sphingomyelinase enzyme level of the patient was low. Unilateral lung lavage was performed in order to decrease lipid storage as a treatment modality. However, there was no clinical or radiological improvement. The patient died at age 15 months due to progressive respiratory failure. Pulmonary involvement is a rare entity in early childhood in patients with NPD type B, but should be considered in the differential diagnosis of persistent interstitial lung disease. It may cause progressive respiratory failure, but the treatment options remain limited. Pediatr Pulmonol. 2005; 40:169,172. © 2005 Wiley-Liss, Inc. [source] Detecting early structural lung damage in cystic fibrosis,,PEDIATRIC PULMONOLOGY, Issue 3 2002Harm A.W.M. Tiddens MD In cystic fibrosis (CF) patients, both severe lung inflammation and severe lung damage occur early and persist throughout life. High-resolution computed tomography (HRCT), a more sensitive method of detecting structural abnormalities than chest X-ray, shows that airways undergo substantial thickening in early CF lung disease. Lung function tests, which are an indirect measure of structural integrity, are insensitive to localized or early damage. Thickening of the peripheral airways causes a reduction in maximal expiratory flow at 25% of forced vital capacity (MEF25) or other measurements of peripheral air flow. Reduced peripheral flows, even in the presence of normal forced expired volume in 1 sec (FEV1) and forced vital capacity (FVC), should be considered an early sign of substantial lung damage and should stimulate aggressive treatment to prevent further deterioration. Pediatr Pulmonol. 2002; 34:228,231. © 2002 Wiley-Liss, Inc. [source] Trabecular bone structure in the mandibular condyles of gouging and nongouging platyrrhine primatesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010Timothy M. Ryan Abstract The relationship between mandibular form and biomechanical function is a topic of significant interest to morphologists and paleontologists alike. Several previous studies have examined the morphology of the mandible in gouging and nongouging primates as a means of understanding the anatomical correlates of this feeding behavior. The goal of the current study was to quantify the trabecular bone structure of the mandibular condyle of gouging and nongouging primates to assess the functional morphology of the jaw in these animals. High-resolution computed tomography scan data were collected from the mandibles of five adult common marmosets (Callithrix jacchus), saddle-back tamarins (Saguinus fuscicollis), and squirrel monkeys (Saimiri sciureus), respectively, and various three-dimensional morphometric parameters were measured from the condylar trabecular bone. No significant differences were found among the taxa for most trabecular bone structural features. Importantly, no mechanically significant parameters, such as bone volume fraction and degree of anisotropy, were found to vary significantly between gouging and nongouging primates. The lack of significant differences in mechanically relevant structural parameters among these three platyrrhine taxa may suggest that gouging as a habitual dietary behavior does not involve significantly higher loads on the mandibular condyle than other masticatory behaviors. Alternatively, the similarities in trabecular architecture across these three taxa may indicate that trabecular bone is relatively unimportant mechanically in the condyle of these primates and therefore is functionally uninformative. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source] High-resolution extracted ion chromatography, a new tool for metabolomics and lipidomics using a second-generation orbitrap mass spectrometerRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 10 2009Albert Koulman Most analytical methods in metabolomics are based on one of two strategies. The first strategy is aimed at specifically analysing a limited number of known metabolites or compound classes. Alternatively, an unbiased approach can be used for profiling as many features as possible in a given metabolome without prior knowledge of the identity of these features. Using high-resolution mass spectrometry with instruments capable of measuring m/z ratios with sufficiently low mass measurement uncertainties and simultaneous high scan speeds, it is possible to combine these two strategies, allowing unbiased profiling of biological samples and targeted analysis of specific compounds at the same time without compromises. Such high mass accuracy and mass resolving power reduces the number of candidate metabolites occupying the same retention time and m/z ratio space to a minimum. In this study, we demonstrate how targeted analysis of phospholipids as well as unbiased profiling is achievable using a benchtop orbitrap instrument after high-speed reversed-phase chromatography. The ability to apply both strategies in one experiment is an important step forward in comprehensive analysis of the metabolome. Copyright © 2009 John Wiley & Sons, Ltd. [source] Increasing throughput and information content for in vitro drug metabolism experiments using ultra-performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometerRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2005Jose Castro-Perez The field of drug metabolism has been revolutionized by liquid chromatography/mass spectrometry (LC/MS) applications with new technologies such as triple quadrupoles, ion traps and time-of-flight (ToF) instrumentation. Over the years, these developments have often relied on the improvements to the mass spectrometer hardware and software, which has allowed users to benefit from lower levels of detection and ease-of-use. One area in which the development pace has been slower is in high-performance liquid chromatography (HPLC). In the case of metabolite identification, where there are many challenges due to the complex nature of the biological matrices and the diversity of the metabolites produced, there is a need to obtain the most accurate data possible. Reactive or toxic metabolites need to be detected and identified as early as possible in the drug discovery process, in order to reduce the very costly attrition of compounds in late-phase development. High-resolution, exact mass measurement plays a very important role in metabolite identification because it allows the elimination of false positives and the determination of non-trivial metabolites in a much faster throughput environment than any other standard current methodology available to this field. By improving the chromatographic resolution, increased peak capacity can be achieved with a reduction in the number of co-eluting species leading to superior separations. The overall enhancement in the chromatographic resolution and peak capacity is transferred into a net reduction in ion suppression leading to an improvement in the MS sensitivity. To investigate this, a number of in vitro samples were analyzed using an ultra-performance liquid chromatography (UPLC) system, with columns packed with porous 1.7,,m particles, coupled to a hybrid quadrupole time-of-flight (ToF) mass spectrometer. This technique showed very clear examples for fundamental gains in sensitivity, chromatographic resolution and speed of analysis, which are all important factors for the demands of today's HTS in discovery. Copyright © 2005 John Wiley & Sons, Ltd. [source] Three-dimensional arytenoid movement induced by vocal fold injections,THE LARYNGOSCOPE, Issue 8 2010Ted Mau MD Abstract Objectives/Hypothesis: To quantitatively characterize arytenoid movement induced by vocal fold injection augmentation in an excised larynx model. Study Design: Laboratory and computational. Methods: Vocal folds of human cadaveric larynges were injected with calcium hydroxylapatite. High-resolution computed tomography scans were obtained before and after injection. Densities corresponding to the arytenoid and cricoid cartilages were extracted and processed with custom MATLAB routines to generate selective three-dimensional reconstructions of the larynx. Pre- and postinjection positions of the arytenoid were compared. Results: Vocal fold injections resulted in predominantly small-magnitude medial rotation and medial translation of the arytenoid. Movements in other directions as would be expected in physiologic adduction were not observed. Conclusions: Vocal fold injection augmentation induced passive movement of the arytenoid that has not been described previously. This movement does not reproduce the trajectory of physiologic adduction. This finding has implications for the treatment of unilateral vocal fold paralysis without arytenoid repositioning maneuvers. Laryngoscope, 2010 [source] High-fidelity spectroscopy at the highest resolutionsASTRONOMISCHE NACHRICHTEN, Issue 5 2010D. Dravins Abstract High-fidelity spectroscopy presents challenges for both observations and in designing instruments. High-resolution and high-accuracy spectra are required for verifying hydrodynamic stellar atmospheres and for resolving intergalactic absorption-line structures in quasars. Even with great photon fluxes from large telescopes with matching spectrometers, precise measurements of line profiles and wavelength positions encounter various physical, observational, and instrumental limits. The analysis may be limited by astrophysical and telluric blends, lack of suitable lines, imprecise laboratory wavelengths, or instrumental imperfections. To some extent, such limits can be pushed by forming averages over many similar spectral lines, thus averaging away small random blends and wavelength errors. In situations where theoretical predictions of lineshapes and shifts can be accurately made (e.g., hydrodynamic models of solar-type stars), the consistency between noisy observations and theoretical predictions may be verified; however this is not feasible for, e.g., the complex of intergalactic metal lines in spectra of distant quasars, where the primary data must come from observations. To more fully resolve lineshapes and interpret wavelength shifts in stars and quasars alike, spectral resolutions on order R = 300 000 or more are required; a level that is becoming (but is not yet) available. A grand challenge remains to design efficient spectrometers with resolutions approaching R = 1 000 000 for the forthcoming generation of extremely large telescopes (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Assessing vertical resolution requirements for operational weather radar data qualityATMOSPHERIC SCIENCE LETTERS, Issue 1 2006Marion P. Mittermaier Abstract High-resolution, 0.28° beamwidth range-height-indicator (RHI) data are used to simulate the reflectivities measured at various ranges by an operational radar with a 1° beamwidth. It is found that the sampling is optimal when the elevation increments equal the beamwidth. Larger increments lead to an unacceptable loss of information. Copyright © 2006 Royal Meteorological Society [source] High-resolution 8 Tesla imaging of the formalin-fixed normal human hippocampusCLINICAL ANATOMY, Issue 2 2005Donald W. Chakeres Abstract The purpose of this study was to evaluate the capacity of high-resolution magnetic resonance imaging (MRI) to visualize the normal anatomic features of the human hippocampus in vitro, using high field imaging equipment, parameters, and acquisition times appropriate for imaging human subjects in vivo. This research compared high field, high-resolution MRI of formalin-fixed normal human hippocampus specimens to histologic sectioning of the same hippocampus samples. Four specimens were evaluated using an 8 Tesla (T), 80 cm bore whole-body MRI scanner equipped with a 12.7 cm single strut transverse electromagnetic resonator (TEM) coil. Hahn spin echo images were acquired with a repetition time (TR) of 800 msec, echo times (TE) of 20, 50, 90, and 134 msec, and an acquisition time (TA) of 3.25 min. The image quality was superb with demonstration of most of the features of the hippocampus. High field, high-resolution MRI can be used to depict multiple layers of the formalin-fixed human hippocampus in vitro using an 8 T whole-body scanner, a TEM coil, and short acquisition times compatible with human imaging in vivo. Clin. Anat. 18:88,91, 2005. © 2005 Wiley-Liss, Inc. [source] Interactive editing of digital fault modelsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 12 2010Jordan Van Aalsburg Abstract We describe an application to interactively create and manipulate digital fault maps, either by tracing existing (paper) fault maps created from geological surveys, or by directly observing fault expressions and earthquake hypocenters in remote sensing data such as high-resolution (,100k × 100k elevation postings) digital elevation models with draped color imagery. Such fault maps serve as input data to finite-element-method simulations of fault interactions, and are crucial to understand regional tectonic processes causing earthquakes, and have tentatively been used to forecast future seismic events or to predict the shaking from likely future earthquakes. This fault editor is designed for immersive virtual reality environments such as CAVEs, and presents users with visualizations of scanned 2D fault maps and textured 3D terrain models, and a set of 3D editing tools to create or manipulate faults. We close with a case study performed by one of our geologist co-authors (Yikilmaz), which evaluates the use of our fault editor in creating a detailed digital fault model of the North Anatolian Fault in Turkey, one of the largest, seismically active strike-slip faults in the world. Yikilmaz, who was directly involved in program development, used our fault editor both in a CAVE and on a desktop computer, and compares it to the industry-standard software package ArcGIS. Copyright © 2009 John Wiley & Sons, Ltd. [source] Early lens development in the zebrafish: A three-dimensional time-lapse analysisDEVELOPMENTAL DYNAMICS, Issue 9 2009Teri M.S. Greiling Abstract In vivo, high-resolution, time-lapse imaging characterized lens development in the zebrafish from 16 to 96 hr postfertilization (hpf). In zebrafish, the lens placode appeared in the head ectoderm, similar to mammals. Delamination of the surface ectoderm resulted in the formation of the lens mass, which progressed to a solid sphere of cells separating from the developing cornea at approximately 24 hpf. A lens vesicle was not observed and apoptosis was not a major factor in separation of the lens from the future cornea. Differentiation of primary fibers began in the lens mass followed by formation of the anterior epithelium after delamination was complete. Secondary fibers differentiated from elongating epithelial cells near the posterior pole. Quantification characterized three stages of lens growth. The study confirmed the advantages of live-cell imaging for three-dimensional quantitative structural characterization of the mechanism(s) responsible for cell differentiation in formation of a transparent, symmetric, and refractile lens. Developmental Dynamics 238:2254,2265, 2009. © 2009 Wiley-Liss, Inc. [source] Clinical uses of high-resolution and high-magnification endoscopy for upper gastrointestinal lesionsDIGESTIVE ENDOSCOPY, Issue 2001Kenjiro Yasuda First page of article [source] Defining the moment of erosion: the principle of thermal consonance timingEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2005D. M. LawlerArticle first published online: 9 DEC 200 Abstract Geomorphological process research demands quantitative information on erosion and deposition event timing and magnitude, in relation to fluctuations in the suspected driving forces. This paper establishes a new measurement principle , thermal consonance timing (TCT) , which delivers clearer, more continuous and quantitative information on erosion and deposition event magnitude, timing and frequency, to assist understanding of the controlling mechanisms. TCT is based on monitoring the switch from characteristically strong temperature gradients in sediment, to weaker gradients in air or water, which reveals the moment of erosion. The paper (1) derives the TCT principle from soil micrometeorological theory; (2) illustrates initial concept operationalization for field and laboratory use; (3) presents experimental data for simple soil erosion simulations; and (4) discusses initial application of TCT and perifluvial micrometeorology principles in the delivery of timing solutions for two bank erosion events on the River Wharfe, UK, in relation to the hydrograph. River bank thermal regimes respond, as soil temperature and energy balance theory predicts, with strong horizontal thermal gradients (often >1 K cm,1 over 6·8 cm). TCT fixed the timing of two erosion events, the first during inundation, the second 19 h after the discharge peak and 13 h after re-emergence from the flow. This provides rare confirmation of delayed bank retreat, quantifies the time-lag involved, and suggests mass failure processes rather than fluid entrainment. Erosion events can be virtually instantaneous, implying ,catastrophic retreat' rather than ,progressive entrainment'. Considerable potential exists to employ TCT approaches for: validating process models in several geomorphological contexts; assisting process identification and improving discrimination of competing hypotheses of process dominance through high-resolution, simultaneous analysis of erosion and deposition events and driving forces; defining shifting erodibility and erosion thresholds; refining dynamic linkages in event-based sediment budget investigations; and deriving closer approximations to ,true' erosion and deposition rates, especially in self-concealing scour-and-fill systems. Copyright © 2005 John Wiley & Sons, Ltd. [source] Close range digital photogrammetric analysis of experimental drainage basin evolutionEARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2003J. Brasington Abstract Despite the difficulties of establishing formal hydraulic and geometric similarity, small-scale models of drainage basins have often been used to investigate the evolution and dynamics of larger-scale landforms. Historically, this analysis has been restricted to planform basin characteristics and only in the last decade has the topographic similarity of experimental landscapes been explored through explicitly three-dimensional parameters such as the distributions of cumulative drainage area, area,slope and catchment elevation. The current emphasis on three-dimensional morphometry reflects a growing awareness of the descriptive paucity of planform data and the need for more robust analysis of spatial scaling relationships. This paradigm shift has been significantly facilitated by technological developments in topographic survey and digital elevation modelling (DEM) which now present the opportunity to acquire and analyse high-resolution, distributed elevation data. Few studies have, however, attempted to use topographic modelling to provide information on the changing pattern and rate of sediment transport though an evolving landscape directly by using multitemporal DEM differencing techniques. This paper reports a laboratory study in which digital photogrammetry was employed to derive high-resolution DEMs of a simulated landscape in declining equilibrium at 15 minute frequency through a 240 minute simulation. Detailed evaluation of the DEMs revealed a vertical precision of 1·2 mm and threshold level of change detection between surfaces of ±3 mm at the 95 per cent confidence level. This quality assurance set the limits for determining the volumetric change between surfaces, which was used to recover the sediment budget through the experiment and to examine local - and basin-scale rates of sediment transport. A comparison of directly observed and morphometric estimates of sediment yield at the basin outlet was used to quantify the closure of the sediment budget over the simulation, and revealed an encouragingly small 6·2 per cent error. The application of this dynamic morphological approach has the potential to offer new insights into the controls on landform development, as demonstrated here by an analysis of the changing pattern of the basin sediment delivery ratio during network growth. Copyright © 2003 John Wiley & Sons, Ltd. [source] High-resolution DNA separation in microcapillary electrophoresis chips utilizing double-L injection techniquesELECTROPHORESIS, Issue 21-22 2004Lung-Ming Fu Abstract An experimental and numerical investigation into the use of high-resolution injection techniques to separate DNA fragments within electrophoresis microchips is presented. The principal material transport mechanisms of electrokinetic migration, fluid flow, and diffusion are considered, and several variable-volume injection methods are discussed. A detailed analysis is provided of a double-L injection technique, which employs appropriate electrokinetic manipulations to reduce sample leakage within the microchip. The leakage effect in electroosmotic flow (EOF) is investigated using a sample composed of rhodamine B and Cy3 dye. Meanwhile, the effects of sample leakage in capillary electrophoresis (CE) separation are studied by considering the separation of 100-base pairs (bp) DNA ladders and HaeIII-digested ,X-174 DNA samples. The present experimental and simulation results indicate that the unique injection system employed in the current microfluidic chip has the ability to replicate the functions of both the conventional cross-channel and the shift-channel injection systems. Furthermore, applying the double-L injection method to these two injection systems is shown to reduce sample leakage significantly. The proposed microfluidic chip and double-L injection technique developed in this study have an exciting potential for use in high-resolution, high-throughput biochemical analysis applications and in many other applications throughout the micrototal analysis systems field. [source] Mechanistic Insights into Acetophenone Transfer Hydrogenation Catalyzed by Half-Sandwich Ruthenium(II) Complexes Containing 2-(Diphenylphosphanyl)aniline , A Combined Experimental and Theoretical StudyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 28 2008Alessia Bacchi Abstract Several new half-sandwich ruthenium(II) complexes containing 2-(diphenyphosphanyl)aniline (PNH2) of formula {Ru[(,2P,N)PNH2](p -cymene)Cl}Y [Y = Cl (1a), PF6 (1b), BF4 (1c), BPh4 (1d), TfO (1e)] were synthesized and fully characterized both in solution (1H NMR and 31P{1H} NMR spectroscopy) and in the solid state (FTIR, X-ray analysis on single crystal). Complexes 1a and 1b are active precatalysts in the hydrogen transfer reaction of acetophenone, leading to tof values up to 4440 h,1. In comparison, the {Ru[(,2P,N)PNMe2](p -cymene)Cl}Cl complex leads to a tof value of 100 h,1 under the same catalytic conditions. The mechanism through which the precatalysts operate was deeply explored by high-resolution MS (ESI) and DFT/PCM studies. The results reveal that the complexes containing PNH2 operate through a bifunctional mechanism analogous to that proposed for diamines and amino alcohol ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] High-resolution estimation for time-variant MIMO channel sounding,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 7 2008Sofia Martinez Lopez A wideband vector channel sounder with 16 parallel RF chains is proposed for parameter estimation in an indoor channel. Low-cost and high-resolution are obtained by using a chirp probe signal, five-port receivers and the MUSIC algorithm. The system covers up to 500,MHz centred at 2.45,GHz. Experimental results show errors inferior to 1,ns in the time domain and of few degrees in the angular domain. Accurate results are found in static as well as in time-variant scenarios. Copyright © 2008 John Wiley & Sons, Ltd. [source] Bivariate combined linkage and association mapping of quantitative trait lociGENETIC EPIDEMIOLOGY, Issue 5 2008Jeesun Jung Abstract In this paper, bivariate/multivariate variance component models are proposed for high-resolution combined linkage and association mapping of quantitative trait loci (QTL), based on combinations of pedigree and population data. Suppose that a quantitative trait locus is located in a chromosome region that exerts pleiotropic effects on multiple quantitative traits. In the region, multiple markers such as single nucleotide polymorphisms are typed. Two regression models, "genotype effect model" and "additive effect model", are proposed to model the association between the markers and the trait locus. The linkage information, i.e., recombination fractions between the QTL and the markers, is modeled in the variance and covariance matrix. By analytical formulae, we show that the "genotype effect model" can be used to model the additive and dominant effects simultaneously; the "additive effect model" only takes care of additive effect. Based on the two models, F -test statistics are proposed to test association between the QTL and markers. By analytical power analysis, we show that bivariate models can be more powerful than univariate models. For moderate-sized samples, the proposed models lead to correct type I error rates; and so the models are reasonably robust. As a practical example, the method is applied to analyze the genetic inheritance of rheumatoid arthritis for the data of The North American Rheumatoid Arthritis Consortium, Problem 2, Genetic Analysis Workshop 15, which confirms the advantage of the proposed bivariate models. Genet. Epidemiol. 2008. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||