bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution and mechanics of long jaws in butterflyfishes (Family Chaetodontidae)
Authors: Ferry‐Graham Lara A. , Wainwright Peter C. , Hulsey C. Darrin , Bellwood David R. 
Published: August 2002

AbstractWe analyzed the functional morphology and evolution of the long jaws found in several butterflyfishes. We used a conservative reanalysis of an existing morphological dataset to generate a phylogeny that guided our selection of seven short‐ and long‐jawed taxa in which to investigate the functional anatomy of the head and jaws: Chaetodon xanthurus, Prognathodes falcifer (formerly Chaetodon falcifer), Chelmon rostratus, Heniochus acuminatus, Johnrandallia nigrirostris, Forcipiger flavissimus, and F. longirostris. We used manipulations of fresh, preserved, and cleared and stained specimens to develop mechanical diagrams of how the jaws might be protruded or depressed. Species differed based on the number of joints within the suspensorium. We used high‐speed video analysis of five of the seven species (C. xanthurus, Chel. rostratus, H. acuminatus, F. flavissimus, and F. longirostris) to test our predictions based on the mechanical diagrams: two suspensorial joints should facilitate purely anteriorly directed protrusion of the lower jaw, one joint should allow less anterior protrusion and result in more depression of the lower jaw, and no joints in the suspensorium should constrain the lower jaw to simple ventral rotation around the jaw joint, as seen in generalized perciform fishes. We found that the longest‐jawed species, F. longirostris, was able to protrude its jaws in a predominantly anterior direction and further than any other species. This was achieved with little input from cranial elevation, the principal input for other known lower jaw protruders, and is hypothesized to be facilitated by separate modifications to the sternohyoideus mechanism and to the adductor arcus palatini muscle. In F. longirostris the adductor arcus palatini muscle has fibers oriented anteroposteriorly rather than medial‐laterally, as seen in most other perciforms and in the other butterflyfish studied. These fibers are oriented such that they could rotate the ventral portion of the quadrate anteriorly, thus projecting the lower jaw anteriorly. The intermediate species lack modification of the adductor arcus palatini and do not protrude their jaws as far (in the case of F. flavissimus) or in a purely anterior fashion (in the case of Chel. rostratus). The short‐jawed species both exhibit only ventral rotation of the lower jaw, despite the fact that H. acuminatus is closely related to Forcipiger. J. Morphol. 248:120–143, 2001. © 2001 Wiley‐Liss, Inc.
Functional morphology of the pectoral fins in bamboo sharks, Chiloscyllium plagiosum: Benthic vs. Pelagic station‐holding
Authors: Wilga Cheryl D. , Lauder George V. 
Published: August 2002

AbstractBamboo sharks (Chiloscyllium plagiosum) are primarily benthic and use their relatively flexible pectoral and pelvic fins to rest on and move about the substrate. We examined the morphology of the pectoral fins and investigated their locomotory function to determine if pectoral fin function during both benthic station‐holding and pelagic swimming differs from fin function described previously in leopard sharks, Triakis semifasciata. We used three‐dimensional kinematics and digital particle image velocimetry (DPIV) to quantify pectoral fin function in five white‐spotted bamboo sharks, C. plagiosum, during four behaviors: holding station on the substrate, steady horizontal swimming, and rising and sinking during swimming. During benthic station‐holding in current flow, bamboo sharks decrease body angle and adjust pectoral fin angle to shed a clockwise fluid vortex. This vortex generates negative lift more than eight times that produced during open water vertical maneuvering and also results in an upstream flow that pushes against the posterior surface of the pectoral fin to oppose drag. In contrast, there is no evidence of significant lift force in the wake of the pectoral fin during steady horizontal swimming. The pectoral fin is held concave downward and at a negative dihedral angle during steady horizontal swimming, promoting maneuverability rather than stability, although this negative dihedral angle is much less than that observed previously in sturgeon and leopard sharks. During sinking, the pectoral fins are held concave upward and shed a clockwise vortex with a negative lift force, while in rising the pectoral fin is held concave downward and sheds a counterclockwise vortex with a positive lift force. Bamboo sharks appear to sacrifice maneuverability for stability when locomoting in the water column and use their relatively flexible fins to generate strong negative lift forces when holding position on the substrate and to enhance stability when swimming in the water column. J. Morphol. 249:195–209, 2001. © 2001 Wiley‐Liss, Inc.
Characterization of cerebral microangiopathy using 3 Tesla MRI: Correlation with neurological impairment and vascular risk factors
Authors: Hund‐Georgiadis Margret , Ballaschke Olaf , Scheid Rainer , Norris David G. , von Cramon D. Yves 
Published: August 2002

AbstractPurposeTo investigate whether clinical and neuropsychological impairment in cerebral small‐vessel disease (CSVD) can be evaluated by means of morphological magnetic resonance imaging (MRI).Materials and MethodsMRI at 3 Tesla in T2‐ and T1‐weighted sequences was evaluated in 44 patients with cerebral microangiopathy, and 30 patients with combined cerebral micro‐ and macroangiopathy. The MR characteristics were correlated to clinical data, attentional impairment, and the patients' individual vascular risk factor profiles. Fifteen healthy age‐matched control subjects participated in the study to assess MR signal changes in nonhypertensive elderly subjects.ResultsPatients and normal controls differed significantly in the extent of MR signal changes. A close relation between age, obesity, hypertension, and MR signal abnormalities was evident in all patients. Patients with pure CSVD additionally showed an association between their MR‐defined severity of disease and their degree of neurological impairment, and their vascular risk score. In contrast, attentional impairment did not relate to the MR‐defined severity of CSVD.ConclusionMR signal changes in CSVD show a close relationship to some risk factors of individual patients. J. Magn. Reson. Imaging 2002;15:1–7. © 2002 Wiley‐Liss, Inc.
Investigation of mechanisms underlying transient T2 normalization in longitudinal studies of ischemic stroke
Authors: Lin Shao‐Pow , Schmidt Robert E. , McKinstry Robert C. , Ackerman Joseph J.H. , Neil Jeffrey J. 
Published: August 2002

AbstractPurposeTo determine if the phenomenon of transient normalization of T2 relaxation in the subacute stage of ischemic stroke is associated with either magnetic susceptibility effects secondary to hemorrhage or changes in tissue water content.Materials and MethodsWe utilized a rat model of transient, focal, cerebral ischemia. The possibility of hemorrhage was evaluated with T2*‐weighted (T2*W) imaging and histology. Changes in water content were assessed by brain wet‐to‐dry weight.ResultsSusceptibility effects were not evident in T2*W images, and neither red blood cells nor unchelated Fe(III) was found in hematoxylin and eosin (H‐E)– or Prussian Blue–stained sections, respectively. However, between the peak of T2 contrast and the point of transient T2 normalization, water content consistently decreased by an average of 3%.ConclusionTransient T2 normalization is associated with normalization of water content and can occur without evidence of hemorrhage. J. Magn. Reson. Imaging 2002;15:130–136. © 2002 Wiley‐Liss, Inc.
Diffusion‐weighted MRI in the characterization of soft‐tissue tumors
Authors: van Rijswijk Catherina S.P. , Kunz Patrik , Hogendoorn Pancras C.W. , Taminiau Antonïe H.M. , Doornbos Joost , Bloem Johan L. 
Published: August 2002

AbstractPurposeTo explore the potential of perfusion‐corrected diffusion‐weighted magnetic resonance imaging (MRI) in characterizing soft‐tissue tumors.Materials and MethodsDiffusion‐weighted MRI was performed in 23 histologically proven soft‐tissue masses using a diffusion‐weighted spin‐echo sequence with diffusion gradient strengths yielding five b‐values (0–701 seconds/mm2). True diffusion coefficients and perfusion fractions were estimated and compared with apparent diffusion coefficients (ADCs).ResultsADC values of all tumors, subcutaneous fat, and muscle were significantly higher than true diffusion coefficients, indicating a contribution of perfusion to the ADC. True diffusion coefficients of malignant tumors (1.08 × 10–3 mm2/second) were significantly lower than those of benign masses (1.71 × 10–3 mm2/second), whereas ADC values between these groups were not significantly different.ConclusionPerfusion‐corrected diffusion‐weighted MRI has potential in differentiating benign from malignant soft‐tissue masses. J. Magn. Reson. Imaging 2002;15:302–307. © 2002 Wiley‐Liss, Inc.
Correction of slab boundary artifact using histogram matching
Authors: Kholmovski Eugene G. , Alexander Andrew L. , Parker Dennis L. 
Published: August 2002

AbstractPurposeTo improve the imaging efficiency of multi‐slab three‐dimensional acquisitions by decreasing slab overlap and the number of blanked slices.Materials and MethodsApplication of the histogram matching technique for correction of the slab boundary artifact (SBA) due to non‐ideal radiofrequency pulse profiles has been proposed. The technique was validated by studying its effectiveness in reducing the SBA in phantom images, as well as in proton density‐ and T2‐weighted brain images.ResultsThe correction algorithm considerably decreases the disruption of image volume continuity due to the SBA, and improves slice‐to‐slice intensity continuity.ConclusionThe proposed technique can greatly reduce the SBA when the SBA can be described as a global intensity variation along the slab. The technique may be used to improve imaging efficiency of the multi‐slab three‐dimensional fast spin‐echo sequences by decreasing the amount of required slab overlap. J. Magn. Reson. Imaging 2002;15:610–617. © 2002 Wiley‐Liss, Inc.
Accurate estimation of pharmacokinetic contrast‐enhanced dynamic MRI parameters of the prostate
Authors: Huisman Henkjan J. , Engelbrecht Marc R. , Barentsz Jelle O. 
Published: August 2002

AbstractQuantitative analysis of contrast‐enhanced dynamic MR images has potential for diagnosing prostate cancer. Contemporary fast acquisition techniques can give sufficiently high temporal resolution to sample the fast dynamics observed in the prostate. Data reduction for parametric visualization requires automatic curve fitting to a pharmacokinetic model, which to date has been performed using least‐squares error minimization methods. We observed that these methods often produce unexpectedly noisy estimates, especially for the typically fast, intermediate parameters time‐to‐peak and start‐of‐enhancement, resulting in inaccurate pharmacokinetic parameter estimates. We developed a new curve fit method that focuses on the most probable slope. A set of 10 patients annotated using histopathology was used to compare the conventional and new methods. The results show that our new method is significantly more accurate, especially in the relatively less‐enhancing periferal zone. We conclude that estimation accuracy depends on the curve fit method, which is especially important when evaluating the periferal zone of the prostate. J. Magn. Reson. Imaging 2001;13:607–614. © 2001 Wiley‐Liss, Inc.
Comparison of gradient encoding schemes for diffusion‐tensor MRI
Authors: Hasan Khader M. , Parker Dennis L. , Alexander Andrew L. 
Published: August 2002

AbstractThe accuracy of single diffusion tensor MRI (DT‐MRI) measurements depends upon the encoding scheme used. In this study, the diffusion tensor accuracy of several strategies for DT‐MRI encoding are compared. The encoding strategies are based upon heuristic, numerically optimized, and regular polyhedra schemes. The criteria for numerical optimization include the minimum tensor variance (MV), minimum force (MF), minimum potential energy (ME), and minimum condition number. The regular polyhedra scheme includes variations of the icosahedron. Analytical comparisons and Monte Carlo simulations show that the icosahedron scheme is optimum for six encoding directions. The MV, MF, and ME solutions for six directions are functionally equivalent to the icosahedron scheme. Two commonly used heuristic DT‐MRI encoding schemes with six directions, which are based upon the geometric landmarks of a cube (vertices, edge centers, and face centers), are found to be suboptimal. For more than six encoding directions, many methods are able to generate a set of equivalent optimum encoding directions including the regular polyhedra, and the ME, MF and MV numerical optimization solutions. For seven directions, a previously described heuristic encoding scheme (tetrahedral plus x, y, z) was also found to be optimum. This study indicates that there is no significant advantage to using more than six encoding directions as long as an optimum encoding is used for six directions. Future DT‐MRI studies are necessary to validate these observations. J. Magn. Reson. Imaging 2001;13:769–780. © 2001 Wiley‐Liss, Inc.
Safety of metallic implants in magnetic resonance imaging
Authors: Ho Henry S. 
Published: August 2002

AbstractMagnetic resonance (MR) imaging has become a commonly accepted medical procedure. Manufacturers of medical implant devices are submitting claims that their devices are safe and effective in a MR environment. This paper concentrates on the issue of heating of patients due to the interaction of metallic implants with the strong radiofrequency (RF) magnetic field produced by the MR scanner. The commercially available program XFDTD was used to calculate the specific absorption rate (SAR) distribution in a realistic model of the human body. The body contained a metallic implant and was exposed to RF magnetic fields at 64 MHz from a model of a MR birdcage body coil. The results of the calculation showed that the magnitude of the increased heating of tissues due to the presence of the metallic implant depended on the dimensions, orientation, shape, and location of the metallic implant in the patient. This increased heating of surrounding tissues primarily concentrates in a small volume near the tip of the metallic wire. When the whole‐body SAR was normalized to 1 W/kg, a calculated value of 41 W/kg was obtained at this location if the absorption was averaged over 1 g of tissue. However, a maximum value of 310 W/kg was calculated when the absorption was averaged over 1/8 g of tissue. J. Magn. Reson. Imaging 2001;14:472–477. Published 2001 Wiley‐Liss, Inc.
Organic ion imaging of biological tissue with secondary ion mass spectrometry and matrix‐assisted laser desorption/ionization
Authors: Todd Peter J. , Schaaff T. Gregory , Chaurand Pierre , Caprioli Richard M. 
Published: August 2002

AbstractOrganic secondary ion mass spectrometry (SIMS) and matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry can be used to produce molecular images of samples. This is achieved through ionization from a clearly identified point on a flat sample, and performing a raster of the sample by moving the point of ionization over the sample surface. The unique analytical capabilities of mass spectrometry for mapping a variety of biological samples at the tissue level are discussed. SIMS provides information on the spatial distribution of the elements and low molecular mass compounds as well as molecular structures on these compounds, while MALDI yields spatial information about higher molecular mass compounds, including their distributions in tissues at very low levels, as well as information on the molecular structures of these compounds. Application of these methods to analytical problems requires appropriate instrumentation, sample preparation methodology, and a data presentation usually in a three‐coordinate plot where x and y are physical dimensions of the sample and z is the signal amplitude. The use of imaging mass spectrometry is illustrated with several biological systems. Copyright © 2001 John Wiley & Sons, Ltd.
A novel tandem quadrupole mass spectrometer allowing gaseous collisional activation and surface induced dissociation
Authors: Mohammed Shabaz , Chalmers Michael J. , Gielbert Janine , Ferro Myriam , Gora Les , Smith D. Charles , Gaskell Simon J. 
Published: August 2002

AbstractA novel tandem quadrupole mass spectrometer is described that enables gaseous collision‐induced dissociation (CID) and surface‐induced dissociation (SID) experiments. The instrument consists of a commercially available triple quadrupole mass spectrometer connected to an SID region and an additional, orthogonal quadrupole mass analyser. The performance of the instrument was evaluated using leucine‐enkephalin, allowing a comparison between CID and SID, and with previous reports of other SID instruments. The reproducibility of SID data was assessed by replicate determinations of the collision energy required for 50% dissociation of leucine‐enkephalin; excellent precision was observed (standard deviation of 0.6 eV) though, unexpectedly, the reproducibility of the equivalent figure for CID was superior. Several peptides were analysed using SID in conjunction with liquid secondary‐ion mass spectrometry or electrospray; a comparison of the fragmentation of singly protonated peptide ions and the further dissociation of y‐type fragments was consistent with the equivalence of the latter fragments to protonated peptides. Few product ions attributable to high‐energy cleavages of amino acid side‐chains were observed. The SID properties were investigated of a series of peptides differing only in the derivatization of a cysteine residue; similar decomposition efficiencies were observed for all except the cysteic acid analogue, which demonstrated significantly more facile fragmentation. Copyright © 2001 John Wiley & Sons, Ltd.
Impaired cytotoxic T lymphocyte response to Epstein‐Barr virus‐infected NK cells in patients with severe chronic active EBV infection
Authors: Tsuge Ikuya , Morishima Tsuneo , Kimura Hiroshi , Kuzushima Kiyotaka , Matsuoka Hiroshi 
Published: August 2002

AbstractClinical evidence of a relationship between severe chronic active Epstein‐Barr virus (EBV) infection and clonal expansion of EBV‐infected T or NK cells has been accumulated. In order to clarify pathogenesis of EBV‐infected cell proliferation in patients with severe chronic active EBV infection, cytotoxic T lymphocyte (CTL) responses of two patients against B‐lymphoblastoid cell lines (B‐LCL) and EBV‐infected NK cells were examined in comparison with those of HLA‐identical healthy siblings. Unexpectedly, patients' CTL activities induced by mixed culture with autologous B‐LCLs were markedly reduced, although uncontrolled EBV‐related B‐cell proliferations have never been experienced. In contrast, limiting dilution analysis demonstrated that B‐LCL‐specific CTL precursor (CTLp) frequencies of patients were comparable to those of their healthy sisters. The existence of normal levels of B‐LCL‐specific T cell responses was confirmed by flow‐cytometric analysis of IFN‐γ‐producing T cells after stimulation with B‐LCLs. Infected NK‐cell‐specific CTLp frequencies of the patients were at undetectable levels despite their expression of latent membrane protein (LMP) 1, suggesting mechanisms to escape immunologic surveillance. In the patients' HLA‐identical healthy sisters, infected NK‐cell‐specific CTLps were detected, and infected NK‐cell‐specific CTL clones could be established. From these findings, two treatment options for severe chronic active EBV infection are offered for consideration: adoptive transfer of in vitro‐cultured CTL, and bone marrow transplantation from HLA‐identical donors. J. Med. Virol. 64:141–148, 2001. © 2001 Wiley‐Liss, Inc.
Multicentered study of viral acute lower respiratory infections in children from four cities of Argentina, 1993–1994*
Authors: Carballal Guadalupe , Videla Cristina M. , Espinosa M. Alejandra , Savy Vilma , Uez Osvaldo , Sequeira María D. , Knez Violeta , Requeijo Paula V. , Posse Clara Riva , Miceli Isabel 
Published: August 2002

AbstractThis study describes the first multicentered study of acute lower respiratory infection viral etiology in young children from four different geographical areas of Argentina. A total of 1,278 children under 5 years of age, hospitalized in primary care centers from Buenos Aires, Córdoba, Santa Fé and Mar del Plata cities during a 2‐year period were studied (1993–1994). Nasopharyngeal aspirates were investigated for respiratory syncytial virus (RSV), adenovirus, parainfluenza, and influenza A and B viruses by indirect immunofluorescence. Out of the patients studied, 946 (74%) were under 1 year of age. Viruses were detected in 399 patients (32%). RSV was observed in 25.3% of the samples, representing 78.2% of all viral positive cases. Adenoviruses were detected in 2.5% of the cases, parainfluenza in 2.2%, influenza A in 2.1%, and influenza B in 0.2%. Compared with other viruses, the higher RSV frequency was statistically significant (P < 0.000). Most RSV cases were detected between May and September with a significant peak in July (P < 0.000). Pneumonia was observed in 46% of the patients, bronchiolitis in 41% and other entities in 13%. The case fatality rate observed during the 2 year study was 0.73%. Most of the above respiratory viruses were detected in the four cities, however, the frequency of RSV and influenza were different in the southern city. J. Med. Virol. 64:167–174, 2001. © 2001 Wiley‐Liss, Inc.
Quantity of cytomegalovirus DNA in different leukocyte populations during active infection in vivo and the presence of gB and UL18 transcripts
Authors: Hassan‐Walker Aycan F. , Mattes Frank M. , Griffiths Paul D. , Emery Vincent C. 
Published: August 2002

AbstractThe quantity of human cytomegalovirus (HCMV) DNA in the blood of immunocompromised individuals correlates with the development of HCMV disease. We wished to determine which leukocytes harboured DNA and whether this represented active viral replication. Magnetic bead separation techniques were used to obtain pure polymorphonuclear leukocyte (PMNL), monocyte, B and T cell fractions, and RT‐PCR and quantitative‐competitive PCR (QC‐PCR) to detect HCMV glycoprotein B (gB; UL55) transcripts and quantify HCMV DNA levels, respectively, in each cell fraction. QC‐PCR revealed that PMNLs contribute the greatest to the overall viral load in blood (median viral load: PMNLs, 105.37 genomes/ml of blood; monocytes, 104.40 genomes/ml; B cells, 103.70 genomes/ml; and T cells, 104.08 genomes/ml). However, monocytes have a viral burden of 0.65 genomes/monocyte which is greater than that within the other leukocyte populations (0.11 genomes/PMNL, 0.23 genomes/B cell, and 0.20 genomes/T cell). Glycoprotein B transcripts were detected in all four cell populations: 3/10 PMNL fractions, 6/13 monocyte fractions, 5/13 B cell fractions, and 4/13 T cell fractions. The data show that productive infection of these leukocyte subpopulations, including PMNLs, can occur in vivo. Furthermore, transcripts of gpUL18, the putative natural killer (NK) cell decoy, were detected in 2/6 monocyte fractions with active replication, and 1/4 T cell fractions but not in the other leukocyte fractions. The transient nature of UL18 gene expression, and the low abundance of the transcript relative to gB were confirmed. J. Med. Virol. 64:283–289, 2001. © 2001 Wiley‐Liss, Inc.