bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manganese speciation in human cerebrospinal fluid using CZE coupled to inductively coupled plasma MS
Authors: Michalke Bernhard , Berthele Achim , Mistriotis Panos , Ochsenkühn‐Petropoulou Maria , Halbach Stefan 
Published: March 2007

AbstractThe neurotoxic effects of manganese (Mn) at elevated concentrations are well known. This raises the question, which of the Mn species can cross neural barriers and appear in cerebrospinal fluid (CSF). CSF is the last matrix in a living human organism available for analysis before a compound reaches the brain cells and therefore it is assumed to reflect best the internal exposure of brain tissue to Mn species. A previously developed CE method was modified for separation of albumin, histidine, tyrosine, cystine, fumarate, malate, inorganic Mn, oxalacetate, α‐keto‐glutarate, nicotinamide‐dinucleotide (NAD), citrate, adenosine, glutathione, and glutamine. These compounds are supposed in the literature to act as potential Mn carriers. In a first attempt, these compounds were analyzed by CZE‐UV to check whether they are present in CSF. The CZE‐UV method was simpler than the coupled CZE‐inductively coupled plasma (ICP)‐dynamic reaction cell (DRC)‐MS method and it was therefore chosen to obtain a first overview information. In a second step, the coupled method (CZE‐ICP‐DRC‐MS) was used to analyze, in detail, which of the compounds found in CSF by CZE‐UV were actually bound to Mn. Finally, 13 Mn species were monitored in CSF samples, most of them being identified: Mn‐histidine, Mn‐fumarate, Mn‐malate, inorganic Mn, Mn‐oxalacetate, Mn‐α‐keto glutarate, Mn‐carrying NAD, Mn‐citrate and Mn‐adenosine. By far the most abundant Mn species was Mn‐citrate showing a concentration of 0.7 ± 0.13 µg Mn/L. Interestingly, several other Mn species can be related to the citric acid cycle.
Dynamic response by large step integration
Authors: Argyris J. H. , Dunne P. C. , Angelopoulos T. 
Published: March 2007

AbstractA family of unconditionally stable algorithms for the economical computation of large linear dynamic systems is described and applied. Possible application to divergent systems is considered and some of the difficulties of extending the use of the algorithms to non‐linear systems are discussed. In the Appendix a previously developed conditionally stable algorithm is applied to the non‐linear gust response of a prestressed cable roof structure over the Munich Olympic Stadium. The idealization involves 1,164 degrees of freedom.
Accuracy of finite difference representations for the transient response analysis of shells
Authors: Underwood Philip 
Published: March 2007

AbstractThe frequency versus wave number characteristics of four O(ΔS2) finite difference formulations for one‐dimensional linear shell (ring and axisymmetric) equations are investigated and compared with the exact continuum characteristics. It is found that three of the formulations give virtually identical results. These are half‐spacing techniques with equilibrium in terms of displacements or resultants and whole‐spacing with equilibrium in terms of displacements. The formulation based on whole‐spacing with equilibrium in terms of resultants produces some dramatically different results. These discrepancies partially explain some late time instability problems and critical time step behaviour that have been reported by other investigators.
The seismic response of a reinforced concrete bridge pier designed to step
Authors: Beck J. L. , Skinner R. I. 
Published: March 2007

AbstractA new technique to enhance the earthquake resistance of tall reinforced‐concrete bridges is introduced whereby the tall piers are allowed to ‘step’ during a severe seismic attack. This means that each pier is free to rock from side to side with vertical separation of parts of the pier from the supporting foundations. This stepping action limits stresses in the reinforced‐concrete piers to values below the yield levels and this should lead to a substantial reduction in the cost of providing earthquake resistanceAs part of a feasibility study, a 200 feet‐high stepping pier is defined and its displacements are calculated for the ground accelerations of the 1940 El Centre earthquake, N‐S component. With no damping present the computations give many ‘stepping’ separations of rather large extent. When the effects of internal structural damping are included in the analysis, there is little reduction in the stepping motions at the level of damping expected in the pier. However, when the computations include the effects of some energy‐absorbing devices of a recently‐developed type, installed between the pier and its foundations, the amplitude and number of the stepping cycles are considerably reduced.
Factors influencing the choice of methods in federal evaluation practice
Authors: Chelimsky Eleanor 
Published: March 2007

AbstractA critical historical review of the tensions in American governance places the method choice debate in a broader perspective. This chapter reviews the factors that influence the evaluation questions posed to evaluators and, in turn, the methods choices that stem from it. Political and professional pressures on the evaluators also influence methods choice. Flexibility in methods is considered essential for the evaluator to design a study that considers both the context and the specifics of the question.
Adding new dimensions to case study evaluations: The case of evaluating comprehensive reforms
Authors: Yin Robert K. , Davis Darnella 
Published: March 2007

AbstractThis chapter describes the adaptation of the case study method to assessing increasingly complex, comprehensive reform initiatives that highlight the blurring of the boundaries between phenomenon and context and the concurrence of multiple interventions. Completed studies of two education reform programs illustrate the ongoing challenges of identifying, measuring, and analyzing large‐scale reforms at multiple levels and across sites.
Methods for evidence‐based practice: Quantitative synthesis of single‐subject designs
Authors: Shadish William R. , Rindskopf David M. 
Published: March 2007

AbstractGood quantitative evidence does not require large, aggregate group designs. The authors describe ground‐breaking work in managing the conceptual and practical demands in developing meta‐analytic strategies for single subject designs in an effort to add to evidence‐based practice.
Stabilized edge‐based finite element simulation of free‐surface flows
Authors: Elias Renato N. , Coutinho Alvaro L. G. A. 
Published: March 2007

AbstractFree‐surface flows occur in several problems in hydrodynamics, such as fuel or water sloshing in tanks, waves breaking in ships, offshore platforms, harbours and coastal areas. The computation of such highly nonlinear flows is challenging since free‐surfaces commonly present merging, fragmentation and breaking parts, leading to the use of interface‐capturing Eulerian approaches. In such methods the surface between two fluids is captured by the use of a marking function which is transported in a flow field. In this work we present a three‐dimensional parallel edge‐based incompressible SUPG/PSPG finite element method to cope with free‐surface problems with volume‐of‐fluid (VOF) extensions to track the evolving free surface. The pure advection equation for the scalar marking function was solved by a fully implicit parallel edge‐based SUPG finite element formulation. We studied variants of this formulation, considering the effects of discontinuity capturing and a particular tangent transformation designed to increase interface sharpness. Global mass conservation is enforced adding or removing mass proportionally to the absolute value of the normal velocity of the interface. We introduce a parallel dynamic deactivation algorithm to solve the marking function equation only in a small region around the interface. The implementation is targeted to distributed memory systems with cache‐based processors. The performance and accuracy of the proposed solution method were tested with several validation problems. Copyright © 2007 John Wiley & Sons, Ltd.
Congenital lung malformations in the second trimester: Prenatal ultrasound diagnosis and pathologic findings
Authors: Harmath Ágnes , Csaba Ákos , Hauzman Erik , Hajdú Júlia , Pete Barbara , Papp Zoltán 
Published: March 2007

AbstractPurpose.To correlate prenatal sonographic diagnosis of cystic lung malformations with fetopathologic findings after termination of pregnancy.Methods.We retrospectively analyzed the data of 16 terminated cases in which a cystic lung lesion was diagnosed pre‐ or postnatally.Results.On average, prenatal diagnosis was established on the 21st gestational week (range, 19–26 weeks). The cause of termination was severe polyhydramnios in 4 cases, nonimmune fetal hydrops in 4 cases, other congenital malformation in 5 cases (renal malformation, 2 cases; congenital diaphragmatic hernia, 3 cases), and obstetrical conditions (intrauterine death, placental abruption, spontaneous abortion) in 3 cases. In 11 cases, congenital cystic adenomatoid malformation (CCAM) was the presumptive prenatal diagnosis. Autopsy confirmed the prenatal diagnosis in 6 of them, while in the other 5 cases, an enteric cyst, a laryngeal atresia, an unidentified tumor, a pulmonary hypoplasia, and an extralobar pulmonary sequestration were found on histologic examination. On the other hand, the autopsy revealed CCAM in those 5 cases in which other malformations were suggested prenatally.Conclusion.The prenatal sonographic diagnosis of CCAM is difficult. Our cases emphasize the important role of fetopathology even today in the verification of prenatal diagnosis based on sonographic examinations. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Left ventricular non‐Hodgkin lymphoma visualized on contrast echocardiography
Authors: Mendiolaza Jesús , Baltasar Jonnah Fatima T. , Anis Ather , Harrison Jonathan , Chen Fan , Klapholz Marc , Saric Muhamed 
Published: March 2007

AbstractWe present a case of AIDS‐related Burkitt's type cardiac lymphoma in a middle‐aged woman with Epstein‐Barr virus infection and profound immunodeficiency. The original features of our case include left ventricular location, female sex, and the use of contrast echocardiography to help establish the diagnosis. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Experimental test of the effects of fluctuating incubation temperatures on hatchling phenotype
Authors: Les Heather L. , Paitz Ryan T. , Bowden Rachel M. 
Published: March 2007

AbstractIn the painted turtle (Chrysemys picta) and red‐eared slider turtle (Trachemys scripta), the temperature that eggs are exposed to during incubation determines the sex of the developing embryo. Constant temperature incubation experiments have shown that for each of these species there is a pivotal temperature that produces a 1:1 sex ratio; higher temperatures bias sex ratios toward females, and lower temperatures toward males. Few studies have examined how fluctuating temperatures, as would be experienced in natural nests, affect hatchling phenotype. Models predict that under fluctuating temperatures sex determination depends on the proportion of development that occurs above or below the pivotal temperature. We tested the effect of fluctuating versus constant temperature incubation regimes on sex ratios and other hatchling traits for both painted and red‐eared slider turtles. Eggs were divided into two treatments with half of the eggs from each species incubated at a constant intermediate temperature, 28.5°C, and half incubated under temperatures that fluctuated 3°C above and below 28.5°C. We converted the fluctuating temperature data into a constant temperature equivalent (CTE) so that we could directly compare constant and fluctuating incubation regimes. The CTE for the fluctuating regime for both species was higher than the constant temperature, which would predict an increase in the production of females. The fluctuating regime did produce a higher proportion of females, but also resulted in increased developmental time and increased hatchling mass, indicating that fluctuating temperatures produce complex effects on hatchling phenotype. J. Exp. Zool. 307A:274–280, 2007. © 2007 Wiley‐Liss, Inc.
Myofibrillar gene expression in differentiating lobster claw muscles
Authors: Medler Scott , Lilley Travis R. , Riehl Jocelyn H. , Mulder Eva P. , Chang Ernest S. , Mykles Donald L. 
Published: March 2007

AbstractLobster claw muscles undergo a process of fiber switching during development, where isomorphic muscles containing a mixture of both fast and slow fibers, become specialized into predominantly fast, or exclusively slow, muscles. Although this process has been described using histochemical methods, we lack an understanding of the shifts in gene expression that take place. In this study, we used several complementary techniques to follow changes in the expression of a number of myofibrillar genes in differentiating juvenile lobster claw muscles. RNA probes complementary to fast and slow myosin heavy chain (MHC) mRNA were used to label sections of 7th stage (∼3 months old) juvenile claw muscles from different stages of the molt cycle. Recently molted animals (1–5 days postmolt) had muscles with distinct regions of fast and slow gene expression, whereas muscles from later in the molt cycle (7–37 days postmolt) had regions of fast and slow MHC expression that were co‐mingled and indistinct. Real‐time PCR was used to quantify several myofibrillar genes in 9th and 10th stages (∼6 months old) juvenile claws and showed that these genes were expressed at significantly higher levels in the postmolt claws, as compared with the intermolt and premolt claws. Finally, Western blot analyses of muscle fibers from juvenile lobsters ∼3 to 30 months in age showed a shift in troponin‐I (TnI) isoform expression as the fibers differentiated into the adult phenotypes, with expression of the adult fast fiber TnI pattern lagging behind the adult slow fiber TnI pattern. Collectively, these data show that juvenile and adult fibers differ both qualitatively and quantitative in the expression of myofibrillar proteins and it may take as much as 2 years for juvenile fibers to achieve the adult phenotype. J. Exp. Zool. 307A:281–295, 2007. © 2007 Wiley‐Liss, Inc.
Thermal variation reveals natural variation between isolates of Caenorhabditis elegans
Authors: Harvey S.C. , Viney M.E. 
Published: March 2007

AbstractThe free‐living nematode Caenorhabditis elegans is distributed globally and found in many varied habitats. However, in comparison to our understanding of the genetics of the species, little is known about natural variation and many major life history traits appear to show only limited differences between isolates. Here we show that temperature affects the lifetime fecundity and the reproductive timing of C. elegans and that there is a genotype by environment interaction, with isolates varying in how lifetime fecundity changes with temperature. We show that the lower lifetime fecundity observed at higher temperatures is primarily due to a reduction in the number of functional sperm. Further, isolates vary in their lifetime fecundity because of inter‐isolate differences in this effect of temperature on the number of functional sperm. J. Exp. Zool. (Mol. Dev. Evol.) 308B:409–416, 2007. © 2007 Wiley‐Liss, Inc.
Adaptation to long sperm in Drosophila: correlated development of the sperm roller and sperm packaging
Authors: Joly Dominique , Luck Nathalie , Dejonghe Béatrice 
Published: March 2007

AbstractSperm are generally small and produced in huge numbers, but some species combine exaggerated sperm length with extremely limited numbers of sperm, an evolutionary trend that deviates from the theory of anisogamy. Sperm gigantism has arisen recurrently in various species, but insects exhibit the longest sperm, with some species of the Drosophilidae family producing sperm up to 6 cm in length. The anatomical, cytological, and physiological requirements for males to cope with these giant sperm were hitherto poorly understood. In this paper, we investigate the internal morphology of the male reproductive tract, and highlight specific features that may be linked to this increase in sperm size. We focus on species in the repleta group, within which sperm length varies by a factor of 35. An associated development of the sperm roller, a special twisting device inserted between the testis and the seminal vesicle, is demonstrated. Its length and the number of coils involved increase with sperm size, and it allows individual sperm to swell and roll into a spermatic pellet before reaching the seminal vesicle. This process occurs independently of and in addition to the sperm bundle coiling that takes place at the base of the testis. It is suggested that the emergence and development of the sperm roller may be a male adaptation to sperm gigantism. J. Exp. Zool. (Mol. Dev. Evol.) 310B:167–178, 2008. © 2007 Wiley‐Liss, Inc.
Gadobenate dimeglumine (BOPTA) enhanced MR imaging: Patterns of enhancement in normal liver and cirrhosis
Authors: Manfredi Riccardo , Maresca Giulia , Baron Richard L. , De Franco Antonio , De Gaetano Anna Maria , Cotroneo Antonio R. , Pirovano Giampaolo , Spinazzi Alberto , Marano Pasquale 
Published: March 2007

AbstractTo determine whether gadobenate dimeglumine (BOPTA) will adequately enhance cirrhotic liver parenchyma, and to document the enhancement patterns in cirrhosis, 14 cirrhotic and 20 non‐cirrhotic patients were evaluated before and 60–120 minutes after gadolinium‐BOPTA. Proof of liver cirrhosis was biopsy (6), surgical resection (3), and clinical follow‐up (5). Enhancement effects were compared quantitatively by determining the liver signal‐to‐noise ratio (SNR) and signal enhancement in both populations. Qualitatively assessment of the liver enhancement was performed and classified as homogeneous or heterogeneous. Quantitative analysis: cirrhotic liver parenchyma presented a higher increase in SNR values, relative to noncirrhotic liver parenchyma, on postcontrast images. Likewise the signal enhancement of cirrhotic liver parenchyma was superior to non‐cirrhotic liver on T1‐weighted SE images (P = .02) and in‐phase GRE images (P < .001). There was no statistical difference on out‐of‐phase GRE images. Qualitative analysis: on T1‐weighted SE postcontrast images, cirrhotic liver parenchyma showed a homogeneous enhancement in 7 patients and heterogeneous in 7. Whereas on GRE images, cirrhotic parenchyma showed heterogeneous enhancement in 9 patients and homogeneous in 5 patients. The heterogeneous enhancement was due to the presence of hypointense nodules in 7 patients and hyperintense nodules in 2 patients. In conclusion, our study has shown that the hepatobiliary contrast agent Gd‐BOPTA is effective in the cirrhotic liver, demonstrating an increased liver enhancement compared with non‐cirrhotic patients.
Sliding interleaved KY (SLINKY) acquisition: A novel 3D MRA technique with suppressed slab boundary artifact
Authors: Liu Kecheng , Rutt Brian K. 
Published: March 2007

AbstractThis work addresses the elimination of the slab boundary artifact (SBA) or venetian blind artifact in three‐dimensional multiple overlapped thin slab acquisition (3D MOTSA) for magnetic resonance angiography (MRA). Our method uses a sliding‐slab, interleaved kY (SLINKY) data acquisition strategy, equalizing flow‐related signal intensity weighting across the entire slab dimension. This technique demodulates signal intensity changes along the slab direction and can essentially eliminate the SBA while retaining the same or better imaging time efficiency than that of conventional MOTSA, providing robustness to complicated flow patterns and thereby resulting in more accurate depiction of vascular morphology. In addition, this technique does not need specialized reconstruction and extra computation. The unique penalty of this technique is the sensitivity to phase inconsistency in the data. Both phantom and in vivo experiments verify the clinical significance of the technique. The new MRA images acquired with this imaging technique show highly reliable mapping of vascular morphology without the SBA and reduction of signal voids in complex/slow flow regions.
Dynamic scan‐plane tracking using MR position monitoring
Authors: Derbyshire J. Andrew , Wright Graham A. , Henkelman R. Mark , Hinks R. Scott 
Published: March 2007

AbstractAn MR‐based method for tracking subject motion is presented. The technique identifies subject motion from the three‐dimensional positions of three small samples attached to the subject in a fixed, triangular configuration. The updated positions of these samples relative to their initial positions determine a rigid body transformation. Applied to the MRI scan prescription via adaptive feedback controls, this transformation yields an updated MRI scan plane that tracks the prescribed imaging section as the subject moves. The scan‐plane tracking procedure is demonstrated experimentally for two‐dimensional imaging of a standard imaging phantom and the head of a human subject. Sets of images were acquired sequentially, with motion (translations and/or rotations) introduced between image frames. The scan‐plane tracking system provides well registered image slices of the same section, adaptively compensating for the subject motion.
Monitoring and visualization techniques for MR‐guided laser ablations in an open MR system
Authors: Kettenbach Joachim , Silverman Stuart G. , Hata Nobuhiko , Kuroda Kagayaki , Saiviroonporn Pairash , Zientara Gary P. , Morrison Paul R. , Hushek Stephen G. , Black Peter McL. , Kikinis Ron , Jolesz Ferenc A. 
Published: March 2007

AbstractOur purpose was to develop temperature‐sensitive MR sequences and image‐processing techniques to assess their potential of monitoring interstitial laser therapy (ILT) in brain tumors (n = 3) and liver tumors (n = 7). ILT lasted 2 to 26 minutes, whereas images from T1‐weighted fast‐spin‐echo (FSE) or spoiled gradient‐recalled (SPGR) sequences were acquired within 5 to 13 seconds. Pixel subtraction and visualization of T1‐weighted images or optical flow computation was done within less than 110 msec. Alternating phase‐mapping of real and imaginary components of SPGR sequences was performed within 220 msec. Pixel subtraction of T1‐weighted images identified thermal changes in liver and brain tumors but could not evaluate the temperature values as chemical shift‐based imaging, which was, however, more affected by susceptibility effects and motion. Optical flow computation displayed the predicted course of thermal changes and revealed that the rate of heat deposition can be anisotropic, which may be related to heterogeneous tumor structure and/or vascularization.
MRI evaluation of acute renal trauma
Authors: Marcos Hani B. , Noone Tara C. , Semelka Richard C. 
Published: March 2007

AbstractWe describe the MR findings in a patient with acute renal injury after blunt abdominal trauma associated with perinephric hematoma and urinoma. Both CT and MR findings are described. Active urine extravasation into a perinephric urinoma is demonstrated by serial post‐contrast imaging with CT and MRI showing progressively increased attenuation/signal intensity fluid in communication with the collecting system, commencing 2 minutes after contrast administration.