bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure, form, and function of flight in engineering and the living world
Authors: Lindhe Norberg Ulla M. 
Published: August 2002

AbstractBy combining appearance and behavior in animals with physical laws, we can get an understanding of the adaptation and evolution of various structures and forms. Comparisons can be made between animal bodies and various technical constructions. Technical science and theory during the latest decades have resulted in considerable insight into biological adaptations, but studies on structures, forms, organs, systems, and processes in the living world, used in the right way, have also aided the engineer in finding wider and better solutions to various problems, among them in the design of micro‐air vehicles (MAVs). In this review, I discuss the basis for flight and give some examples of where flight engineering and nature have evolved similar solutions. In most cases technology has produced more advanced structures, but sometimes animals are superior. I include how different animals have solved the problem of producing lift, how animal wings meet the requirements of strength and rigidity, how wing forms are adapted to various flight modes, and how flight kinematics are related to flight behavior and speed. The dynamics of vorticity is summarized. There are a variety of methods for the determination of flight power; it has been estimated adequately by lifting‐line theory, by physiological measurements, and from mass loss and food intake. In recent years alternative methods have been used, in which the mechanical power for flight is estimated from flight muscle force used during the downstroke. Refinements of these methods may create new ways of estimating flight power more accurately. MAVs operate at the same Reynolds numbers as large insects and small birds and bats. Therefore, studies on animal flight are valuable for MAV design, which is discussed here. J. Morphol. 252:52–81, 2002. © 2002 Wiley‐Liss, Inc.
Direct monitoring of molecular recognition processes using fluorescence enhancement at colloid‐coated microplates
Authors: Lobmaier Ch. , Hawa G. , Götzinger M. , Wirth M. , Pittner F. , Gabor F. 
Published: August 2002

AbstractDirect monitoring of recognition processes at the molecular level is a valuable tool for studying reaction kinetics to assess affinity constants (e.g. drugs to receptors) and for designing rapid single step immunoassays. Methods currently used to gain information about binding processes predominantly depend on surface plasmon resonance. These systems use excitation with coherent light in attenuated total reflection geometry to obtain discrimination between surface‐bound and free molecules in solution. Therefore labeling of the compounds is not necessary, but due to the complexity of the measuring setup the method is rather costly. In this contribution we present a simple method for performing kinetic single step biorecognition assays with fluorophore labeled compounds using the fluorescence enhancement properties of surface bound silver colloids. Silver colloids are bound to standard microplates via silanization of the plastic surface. Fluorophores close to this colloid coated surface show a significant gain in fluorescence compared to fluorophores farther away in the bulk solution. Therefore discrimination between surface bound and free fluorophores is possible and the binding of, for example, fluorophore labeled antibodies to antigens immobilized on the colloid surface results in increasing fluorescence intensity. Utilization of standard microplates makes this method fully compatible with conventional microplate processing and reading devices. Neither excitation with coherent laser light nor ATR geometry is required, the measurement is performed in a standard fluorescence microplate reader in front face geometry with a xenon flash lamp as excitation source. Methods for the preparation of colloid‐coated microplates and fluorescence‐enhanced biorecognition assays are presented. Additionally the dependence of the system performance on the structure and properties of the metal colloid coated surface is described. A two‐component biorecognition model system shows a detection limit in the subnanomolar range. The ease of colloid‐surface preparation and the high sensitivity makes fluorescence enhancement at colloid‐coated microplates a valuable tool for studying reaction kinetics and performing rapid single‐step immunoassays. Copyright © 2001 John Wiley & Sons, Ltd.
Oxytocin‐induced phosphorylation of myosin light chain is mediated by extracellular calcium influx in pregnant rat myometrium
Authors: Shojo Hideki , Kaneko Yuji 
Published: August 2002

AbstractStudies of oxytocin‐induced phosphorylation of myosin light chain (MLC), resulting in myometrial contraction, suggest that extracellular Ca2+ influx is involved in its signal transduction. To explore the possibility that intracellular Ca2+ mobilization by oxytocin may also contribute to MLC phosphorylation, we investigated the relative contributions of these Ca2+ sources to oxytocin signal transduction in myometrium of pregnant rat. In pregnant rat myometrium, oxytocin‐induced Ca2+ influx occurs via an L‐type voltage‐dependent Ca2+ channel. Treatment with verapamil, an antagonist specific for these channels, significantly diminished MLC phosphorylation observed in response to oxytocin administration without affecting the release of Ca2+ from intracellular Ca2+ stores. Furthermore, oxytocin‐induced MLC phosphorylation was not observed when extracellular Ca2+ was not present. Our results clearly indicate that extracellular Ca2+ influx, rather than release from Ca2+ storage sites, is essential for oxytocin‐induced MLC phosphorylation. Copyright © 2001 John Wiley & Sons, Ltd.
Mycotic aortocaval fistula: Efficient evaluation by bolus‐chase MR angiography
Authors: Torigian Drew A. , Carpenter Jeffrey P. , Roberts David A. 
Published: August 2002

AbstractAortocaval fistula (ACF) is a rare but life‐threatening condition. This case report describes the use of bolus‐chase gadolinium‐enhanced 3D magnetic resonance angiography (MRA) to provide an efficient evaluation of a patient with ACF associated with a mycotic abdominal aortic aneurysm. This case highlights the ability of bolus‐chase MRA to provide both the specific diagnosis of ACF as well as the information necessary for extra‐anatomic arterial bypass. Bolus‐chase MRA is a promising method for the evaluation of patients with this disease entity. J. Magn. Reson. Imaging 2002;15:195–198. © 2002 Wiley‐Liss, Inc.
In vivo diffusion tensor imaging of human calf muscle
Authors: Sinha Usha , Yao Lawrence 
Published: August 2002

AbstractPurposeTo investigate a tetrahedral diffusion gradient encoding scheme to measure the diffusion tensor in vivo for human calf muscle.Materials and MethodsThe theoretical TE which maximizes the signal‐to‐noise ratio (SNR) of the diffusion images was derived for both the orthogonal and tetrahedral sampling strategies and the SNR advantage verified experimentally. A diffusion echo‐planar imaging (EPI) sequence was used to image five volunteers. Gradient cycling and geometric averaging was performed to eliminate cross‐terms between the imaging and diffusion gradients.ResultsTrace diffusion coefficients in human muscle are spatially invariant and have low intersubject variability (<4%). Images of the off‐diagonal terms confirm the anisotropy of muscle, and fiber orientation maps were derived from these off‐diagonal images. A noninvariant index of anisotropy, Aratio (average value: 1.28), was found to be less susceptible to noise than the invariant index.ConclusionThis technique is robust and can be readily implemented on clinical scanners with EPI capabilities. J. Magn. Reson. Imaging 2002;15:87–95. © 2002 Wiley‐Liss, Inc.
Fast phase contrast cardiac magnetic resonance imaging: Improved assessment and analysis of left ventricular wall motion
Authors: Markl Michael , Schneider Britta , Hennig Jürgen 
Published: August 2002

AbstractPurposeTo evaluate the use of CINE phase contrast magnetic resonance imaging (MRI) to assess and characterize left ventricular wall motion by two‐ or three‐directional velocity vector fields that reflect the temporal evolution of myocardial velocities over the whole cardiac cycle.Material and MethodsA fast imaging protocol is presented that permits the assessment of the pixel‐wise full in‐plane velocity information of the beating heart within a single breath‐hold measurement. Temporal resolution of the acquired images is improved by the use of high‐speed gradients and application of view sharing to black blood k‐space segmented gradient echo imaging. A novel tool for data analysis is presented based on correlating locally different myocardial motion patterns to averaged left ventricular velocities reflecting nonpathological myocardial function.ResultsMeasurement protocol and postprocessing options were evaluated in a study with 16 normal volunteers. Simulations showed that correlation analysis can be used to differentiate regions with altered velocity waveforms from global radial velocities. Results of patient examinations are presented on an exemplary basis and demonstrate that correlation analysis provides an effective method for identification and classification of myocardial dynamics.ConclusionWithin the framework of our volunteer and patient examinations, fast phase contrast cardiac MRI has proven to be a reliable method to assess and analyze myocardial performance on the basis of two‐directional velocity vector fields. J. Magn. Reson. Imaging 2002;15:642–653. © 2002 Wiley‐Liss, Inc.
Real‐time MRI of joint movement with trueFISP
Authors: Quick Harald H. , Ladd Mark E. , Hoevel Matthias , Bosk Silke , Debatin Joerg F. , Laub Gerhard , Schroeder Tobias 
Published: August 2002

AbstractPurposeTo develop a technique for dynamic magnetic resonance imaging (MRI) of joint motion based on a combination of real‐time TrueFISP (fast imaging with steady state precession) imaging with surface radiofrequency (RF) coils.Materials and MethodsThe metacarpal, elbow, tarsal, and knee joint of five volunteers and the knees of four patients were examined with a real‐time TrueFISP sequence during movement of the joints.ResultsAll examined joints could be assessed under dynamic conditions with high image contrast and high temporal resolution.ConclusionDynamic MRI of joints with TrueFISP is feasible and can provide information supplemental to static joint examinations. J. Magn. Reson. Imaging 2002;15:710–715. © 2002 Wiley‐Liss, Inc.
Prediction of postoperative pulmonary function using perfusion magnetic resonance imaging of the lung
Authors: Iwasawa Tae , Saito Kimihiko , Ogawa Nobuo , Ishiwa Naoki , Kurihara Hiroaki 
Published: August 2002

AbstractPurposeTo assess semiquantitatively the regional distribution of lung perfusion using magnetic resonance (MR) perfusion imaging.Materials and MethodsSubjects were 20 consecutive patients with bronchogenic carcinoma, who underwent MR imaging (MRI) and radionuclide (RN) perfusion scans for preoperative evaluation. Three‐dimensional (3D) images of whole lungs were obtained before and 7 seconds after bolus injection of contrast material (5 ml of Gd‐DTPA). Subtraction images were constructed from these dynamic images. Lung areas enhanced with the contrast material were measured and multiplied by changes in signal intensity, summed for the whole lung, and the right‐to‐left lung ratios were calculated. The predicted postoperative forced expiratory volume in 1 second (FEV1) was estimated using MR and RN perfusion ratios.ResultsThe correlation between perfusion ratios derived from the MR and RN studies was excellent (r = 0.92). Sixteen of 20 patients underwent surgery, and 12 patients had postoperative pulmonary function tests. The predicted FEV1 derived from the MR perfusion ratio correlated well with the postoperative FEV1 in the 12 patients (r = 0.68).ConclusionPerfusion MRI is suitable for semiquantitative evaluation of regional pulmonary perfusion. J. Magn. Reson. Imaging 2002;15:685–692. © 2002 Wiley‐Liss, Inc.
Hyperpolarized 3He MR lung ventilation imaging in asthmatics: Preliminary findings
Authors: Altes Talissa A. , Powers Patrick L. , Knight‐Scott Jack , Rakes Gary , Platts‐Mills Thomas A.E. , de Lange Eduard E. , Alford Bennett A. , Mugler John P. , Brookeman James R. 
Published: August 2002

AbstractAsthma is a disease characterized by chronic inflammation and reversible obstruction of the small airways resulting in impaired pulmonary ventilation. Hyperpolarized 3He magnetic resonance (MR) lung imaging is a new technology that provides a detailed image of lung ventilation. Hyperpolarized 3He lung imaging was performed in 10 asthmatics and 10 healthy subjects. Seven asthmatics had ventilation defects distributed throughout the lungs compared with none of the normal subjects. These ventilation defects were more numerous and larger in the two symptomatic asthmatics who had abnormal spirometry. Ventilation defects studied over time demonstrated no change in appearance over 30–60 minutes. One asthmatic subject was studied twice in a three‐week period and had ventilation defects which resolved and appeared in that time. This same subject was studied before and after bronchodilator therapy, and all ventilation defects resolved after therapy. Hyperpolarized 3He lung imaging can detect the small, reversible ventilation defects that characterize asthma. The ability to visualize lung ventilation offers a direct method of assessing asthmatics and their response to therapy. J. Magn. Reson. Imaging 2001;13:378–384. © 2001 Wiley‐Liss, Inc.
Ultrasmall particulate iron oxides as contrast agents for magnetic resonance spectroscopy: A dose‐effect study
Authors: Le Duc Géraldine , Vander Elst Luce , Colet Jean Marie , Roch Alain , Gillis Pierre , Le Bas Jean François , Muller Robert N. 
Published: August 2002

AbstractLong‐distance effects of a superparamagnetic contrast agent (AMI227) were investigated by phosphorus‐31 NMR spectroscopy at 7.05 Tesla. In an initial methodological approach, the effects observed on phantoms were compared to the results of theoretical calculations. In a second step, the particles were administered to excised and perfused rat livers (N = 5) and hearts (N = 5) through the perfusion medium for 12 minutes at various concentrations (0.9, 1.8, and 3.6 mM Fe). Organs were subsequently rinsed with the perfusion medium for 42 minutes. During particle perfusion, the spectral lines were shifted and exhibited a strong broadening, although the peak area remained constant, testifying to the inocuity of the material. For hearts only, these disturbances disappeared upon organ rinsing. These through‐space susceptibility effects of the particles located in the vessels on phosphorus nuclei, which are strictly confined to the intracellular space, show that high‐susceptibility intravascular agents could be useful to evaluate tissue perfusion by contrast‐enhanced spectroscopy. J. Magn. Reson. Imaging 2001;13:619–626. © 2001 Wiley‐Liss, Inc.
Necropsy by magnetic resonance in a case of conjoined thoracopagus twins
Authors: Manzano A.C. , Morillo A.J. , Vallejo J.M. , Bayona M.P. 
Published: August 2002

AbstractA case of thoracopagus conjoined stillborn twins studied with magnetic resonance imaging (MRI) is presented. Due to the parents' denial of authorization for an autopsy of the fetuses, the MRI study was performed as an alternative to necropsy. High‐resolution images of the fetuses demonstrated relevant anatomic features, providing noninvasive pathological insight with preservation of the fetal specimen. J. Magn. Reson. Imaging 2001;13:976–981. © 2001 Wiley‐Liss, Inc.
Fat‐suppressed T2‐weighted MRI of the liver: Comparison of respiratory‐triggered fast spin‐echo, breath‐hold single‐shot fast spin‐echo, and breath‐hold fast‐recovery fast spin‐echo sequences
Authors: Katayama Motoyuki , Masui Takayuki , Kobayashi Shigeru , Ito Tatsuhiko , Takahashi Mamoru , Sakahara Harumi , Nozaki Atsushi , Kabasawa Hiroyuki 
Published: August 2002

AbstractThe purpose of our study was to compare the value of respiratory‐triggered fast spin‐echo, breath‐hold single‐shot fast spin‐echo, and breath‐hold fast‐recovery fast spin‐echo sequences in detecting hepatic lesions. Fat‐suppressed T2‐weighted magnetic resonance (MR) images obtained with the three sequences in 36 patients with 138 lesions and nine patients without lesions were prospectively analyzed. Quantitative and qualitative analyses, including receiver operating characteristic (ROC) analyses, were performed. The mean lesion‐to‐liver contrast‐to‐noise ratio (CNR) for hepatic lesions was highest with the respiratory‐triggered fast spin‐echo sequence. On the basis of receiver‐operating characteristic analyses, tumor detection rates were higher with the breath‐hold fast‐recovery fast spin‐echo sequence (Az = 0.94) than with the respiratory‐triggered fast spin‐echo sequence (AZ = 0.80, P < 0.0001) or the single‐shot fast spin‐echo sequence (Az = 0.77, P < 0.0001). The image quality with the breath‐hold fast‐recovery fast spin‐echo sequence was acceptable in all patients. The breath‐hold fast‐recovery fast spin‐echo sequence provided the highest tumor detection in a short imaging time, although the mean lesion‐to‐liver CNRs were inferior to those of the respiratory‐triggered fast spin‐echo and the breath‐hold single‐shot fast spin‐echo sequences. J. Magn. Reson. Imaging 2001;14:439–449. © 2001 Wiley‐Liss, Inc.
Serial cine‐magnetic resonance imaging of left ventricular remodeling after myocardial infarction in rats
Authors: Nahrendorf Matthias , Wiesmann Frank , Hiller Karl‐Heinz , Hu Kai , Waller Christiane , Ruff Jan , Lanz Titus E. , Neubauer Stefan , Haase Axel , Ertl Georg , Bauer Wolfgang R. 
Published: August 2002

AbstractThe purpose of the present study was the serial investigation of morphological and functional changes after left coronary artery ligation in the intact rat using cine‐magnetic resonance imaging (MRI). MRI studies were performed 4, 8, 12, and 16 weeks after myocardial infarction (MI) with an echocardiogram (ECG)‐triggered cine‐fast low‐angle shot (FLASH)‐sequence in a 7‐Tesla magnet. MI‐size, left ventricular (LV) mass and volumes, cardiac index, ejection fraction (EF), and remote wall and scar thickness of 11 Wistar rats were compared to four sham‐operated rats. Stress MRI with dobutamine (10 μl/kg × minute) was performed at 16 weeks. In MI groups (small MI < 30%, N = 5, large MI > 30%, N = 6), there was significant increase of LV mass (small MI + 47.8% increase, large MI + 74.1%) and wall thickness (large MI 1.21 ± 0.03 to 1.84 ± 0.07 mm). Scar thickness declined from four to 16 weeks (large MI 0.92 ± 0.06 to 0.38 ± 0.02mm, P < 0.05). End‐diastolic volume of both MI groups was significantly elevated but increased further only in animals with large MI from four to 16 weeks (657.1 ± 38.6 to 869.7 ± 60.7 μL, P < 0.05). Compared to sham, EF was significantly depressed in MI (large MI 31.5 ± 2.0%). Wall thickening declined from four to 16 weeks post‐MI (large MI 50.9 ± 9.9 to 28.9 ± 4.4%, P < 0.05). During stress, sham and MI rats increased wall thickening from 66.5 ± 8.2 to 111.2 ± 6.7% and from 30.8 ± 4.3 to 47.5 ± 5.8%, respectively (P < 0.05). Hypertrophy was found in all animals with MI throughout the entire period of observation, whereas dilatation after four weeks was only detected in animals with large MI. These morphologic changes were accompanied by an early decline of EF; myocardial function characterized by wall thickening deteriorated later. J. Magn. Reson. Imaging 2001;14:547–555. © 2001 Wiley‐Liss, Inc.
Mass spectrometry in coupling with affinity capture–release and isotope‐coded affinity tags for quantitative protein analysis
Authors: Tureček František 
Published: August 2002

AbstractAffinity capture–release electrospray ionization mass spectrometry (ACESIMS) and isotope‐coded affinity tags (ICAT) are two recently introduced techniques for the quantitation of protein activity and content with applications to clinical enzymology and functional proteomics, respectively. One common feature of these methods is that they use biotinylated tags that function as molecular handles for highly selective and reversible affinity capture of conjugates from complex biological mixtures such as cell homogenates and sub‐cellular organelles. ACESIMS uses synthetic substrate conjugates specifically to target cellular enzymes that, when deficient, are the cause of genetic diseases. Multiplex determination of enzyme activities is used for the diagnosis of lysosomal storage diseases. The ICAT method relies on selective conjugation of cysteine thiol groups in proteins, followed by enzymatic digestion and quantitative analysis of peptide conjugates by mass spectrometry. Another common feature of the ACESIMS and ICAT approaches is that both use conjugates labeled with stable heavy isotopes as internal standards for quantitation. Selected applications of the ACESIMS and ICAT techniques are presented that include molecular‐level diagnosis of genetic diseases in children and quantitative determination of protein expression in cells. Copyright © 2001 John Wiley & Sons, Ltd.
Predominance of genotype A HBV in an HBV‐HIV‐1 dually positive population compared with an HIV‐1–negative counterpart in Japan
Authors: Koibuchi Tomohiko , Hitani Akihiro , Nakamura Tetsuya , Nojiri Noriyuki , Nakajima Kazunori , Jyuji Takeo , Iwamoto Aikichi 
Published: August 2002

AbstractHepatitis B virus (HBV) has seven genotypes, A to G. Previous studies have shown that genotype C is the most prevalent strain in chronic HBV carriers in East Asia. This study was undertaken to investigate the epidemiology of HBV genotypes among Japanese patients who are coinfected with human immunodeficiency virus type 1 (HIV‐1). The sequences of the complete hepatitis B surface antifen (HBsAg) genes were obtained from 18 coinfected Japanese patients. Among the 18 patients, 12 of 13 men who had sex with men (MSM) had genotype A (92%), whereas only one of five heterosexual or hemophiliac patients had genotype A. The predominance of genotype A HBV in MSM showed a striking contrast to the current genotype prevalence in the Japanese population. Owing to the recent decrease in the rate of vertical transmission in Japan, the role of sexual behavior in the transmission of HBV cannot be overestimated. Thus, the relative proportion of genotype A may gradually increase in Japan. J. Med. Virol. 64:435–440, 2001. © 2001 Wiley‐Liss, Inc.