bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal‐Nonmetal Transition in Dense Plasmas
Authors: Juranek H. , Nettelmann N. , Kuhlbrodt S. , Schwarz V. , Holst B. , Redmer R. 
Published: August 2005

AbstractWe have developed a theoretical approach to the equation of state of dense plasmas which has been applied to hydrogen and deuterium, various metals and noble gases. We compare Hugoniot curves and the sound speed with shock‐wave experiments and other theoretical predictions. Especially, the nonmetal‐to‐metal transition which occurs in dense plasmas at high pressures is discussed by means of the electrical conductvity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fetal oxygen tension promotes tenascin‐C–dependent lung branching morphogenesis
Authors: Gebb Sarah A. , Fox Keith , Vaughn Jessica , McKean David , Jones Peter Lloyd 
Published: August 2005

AbstractTenascin‐C (TN‐C) is a mesenchyme‐derived extracellular matrix (ECM) glycoprotein required for fetal lung branching morphogenesis. Given that the low oxygen (O2) environment of the fetus is also essential for normal lung branching morphogenesis, we determined whether fetal O2 tension supports this process by promoting TN‐C expression. Initial studies showed that 15‐day fetal rat lung explants cultured for 2 days at 3% O2 not only branched well, but they also expressed higher levels of TN‐C when compared to lungs maintained at 21% O2, which branched poorly. Antisense oligonucleotide studies demonstrated that TN‐C produced in response to 3% O2 was essential for lung branching morphogenesis. As well, exogenous TN‐C protein was shown to promote branching of lung epithelial rudiments cultured at 21% O2. Because ECM‐degrading proteinases are capable of catabolizing TN‐C protein, we reasoned that 3% O2 might promote TN‐C deposition by limiting the activity of these enzymes within the fetal lung. Consistent with this idea, gelatin zymography showed that the activity of a 72‐kDa gelatinase, identified as matrix metalloproteinase‐2 (MMP‐2), was lower at 3% O2 vs. 21% O2. Furthermore, pharmacologic inhibition of MMP‐2 activity in fetal lung explants cultured at 21% O2 resulted in increased TN‐C deposition within the mesenchyme, as well as enhanced branching morphogenesis. Collectively, these studies indicate that fetal O2 tension promotes TN‐C–dependent lung epithelial branching morphogenesis by limiting the proteolytic turnover of this ECM component within the adjacent mesenchyme. Developmental Dynamics 234:1–10, 2005. © 2005 Wiley‐Liss, Inc.
Dynamics and unexpected localization of the plakin binding protein, kazrin, in mouse eggs and early embryos
Authors: Gallicano G. Ian , Foshay Kara , Pengetnze Yolande , Zhou Xuan 
Published: August 2005

AbstractThe cell uses the cytoskeleton in virtually every aspect of cell survival and function. One primary function of the cytoskeleton is to connect to and stabilize intercellular junctions. To accomplish this task, microtubules, actin filaments, and intermediate filaments utilize cytolinker proteins, which physically bind the cytoskeletal filament to the core proteins of the adhesion junction. The plakin family of linker proteins have been in the spotlight recently as critical components for embryo survival and, when mutated, the cause of diseases such as muscular dystrophy and cardiomyopathies. Here, we reveal the dynamics of a recently discovered plakin binding protein, kazrin (kaz), during early mouse development. Kaz was originally found in adult tissues, primarily epidermis, linking periplakin to the plasma membrane and colocalizing with desmoplakin in desmosomes. Using reverse transcriptase‐polymerase chain reaction, Western blots, and confocal microscopy, we found kaz in unfertilized eggs associated with the spindle apparatus and cytoskeletal sheets. As quickly as 5 min after egg activation, kaz relocates to a diffuse peri‐spindle position, followed 20–30 min later by clear localization to the presumptive cytokinetic ring. Before the blastocyst stage of development, kaz associates with the nuclear matrix in a cell cycle‐dependent manner, and also associates with the cytoplasmic actin cytoskeleton. After blastocyst formation, kaz localization and potential function(s) become highly complex as it is found associating with cell–cell junctions, the cytoskeleton, and nucleus. Postimplantation stages of development reveal that kaz retains a multifunctional, tissue‐specific role as it is detected at diverse locations in various embryonic tissue types. Developmental Dynamics 234:201–214, 2005. © 2005 Wiley‐Liss, Inc.
Reorganization of actin cytoskeleton by FRIED, a Frizzled‐8 associated protein tyrosine phosphatase
Authors: Itoh Keiji , Lisovsky Mikhail , Hikasa Hiroki , Sokol Sergei Y. 
Published: August 2005

AbstractFrizzled receptors transduce signals from the extracellular Wnt ligands through multiple signaling pathways that affect cytoskeletal organization and regulate gene expression. Direct intracellular mediators of Frizzled signaling are largely unknown. We identified FRIED (Frizzled interaction and ectoderm defects) by its association with the C‐terminal PDZ‐binding motif of Xenopus Frizzled 8. FRIED contains an N‐terminal KIND domain, a FERM domain, six PDZ domains, and a tyrosine phosphatase domain, being similar in structure to the protein tyrosine phosphatase PTP‐BAS/PTP‐BL. We report that FRIED proteins with the FERM domain localize to the apical cortex and can inhibit Wnt8‐mediated, but not β‐catenin‐mediated, secondary axis induction in Xenopus embryos, suggesting a specific interaction with Wnt signaling. A FRIED construct containing the FERM domain induced reorganization of pigment granules and cortical actin in Xenopus ectoderm. Wnt5a suppressed the depigmentation of ectoderm triggered by FRIED, demonstrating that Wnt5a and FRIED functionally interact to regulate the cytoskeletal organization. Our data are consistent with the possibility that FRIED functions by modulating Rac1 activity. We propose that FRIED is an adaptor protein that serves as a molecular link between Wnt signaling and actin cytoskeleton. Developmental Dynamics 234:90–101, 2005. © 2005 Wiley‐Liss, Inc.
Cell death during germ band inversion, dorsal closure, and nervous system development in the spider Cupiennius salei
Authors: Prpic Nikola‐Michael , Damen Wim G.M. 
Published: August 2005

AbstractCell death is an important feature in the development of animals, because it is one possibility for the embryo to control cell number in developing tissues and thereby determine the form of a growing organ. In Drosophila, cell death has been shown to be involved in the shaping of many different organs of the embryo. We have used terminal deoxynucleotidyl transferase‐mediated dUTP‐digoxygenin nick end labeling (TUNEL) and an antibody against the activated form of caspase‐3 to visualize cell death in the spider Cupiennius salei. We find that similar to Drosophila, massive cell death occurs during the development of the nervous system, suggesting that this is an ancestral feature in the arthropods. We also detect cell death during leg development, most probably related to the formation of tarsal sensory organs. No cell death seems to be required for germ band segmentation. Most importantly, we find that cell death has a role in germ band inversion, a morphogenetic event unique to spiders that involves epithelial fission ventrally and tissue fusion dorsally. Our data show that germ band inversion involves cell death to facilitate the ventral splitting of the germ band, as well as the epithelial fusion during dorsal closure. Developmental Dynamics 234:222–228, 2005. © 2005 Wiley‐Liss, Inc.
Localization of Apaf1 gene expression in the early development of the mouse by means of in situ reverse transcriptase‐polymerase chain reaction
Authors: Müller Matthias , Berger Joachim , Gersdorff Nikolaus , Cecconi Francesco , Herken Rainer , Quondamatteo Fabio 
Published: August 2005

AbstractApoptosis is an essential ubiquitous process that controls the duration of the life span of cells, thus playing a crucial role in morphogenetic, histogenetic, and phylogenetic developmental processes. Apaf1 (apoptosis protease activating factor 1) is one of the central mediators of the intrinsic apoptotic pathway and a part of the apoptosome, which activates procaspase‐3 and promotes cell death. Gene knockout of Apaf1 in mice leads to late embryonic lethality with malformations such as the persistence of interdigital webs and hyperplasia of brain and retina. Therefore, Apaf1 is generally believed to play a crucial role in developmental apoptosis and have a widespread expression. However, its pattern of expression in early development remains unknown. To specify whether Apaf1 indeed plays this key role, we investigated the pattern of gene expression for Apaf1 in mouse embryos on day 7, 9, and 12 of development. Our results show, that gene expression for Apaf1 first occurs within the embryo between day 7 and 9 of development, becoming more widespread toward day 12 and then includes structures, such as yolk sac, mesenchyme, cartilage, heart anlage, otic vesicle, peridermis, and anlagen of the spinal ganglia and vertebral bodies. Our results also show that gene expression for Apaf1 is not ubiquitous in early mouse development. This finding indicates that cell death processes are independent of or less dependent on Apaf1 during this time. Of interest, an active gene expression for Apaf1 is also present in organ anlagen such as heart or intestine, in which no obvious phenotype is seen after Apaf1 deletion. This finding suggests a possible role for Apaf1 in such anlagen as a putative alternative compensatory pathway, which could be switched on in the case of defects in the mediators that are normally involved in such organs. Developmental Dynamics 234:215–221, 2005. © 2005 Wiley‐Liss, Inc.
Chromatic numbers of products of graphs: The directed and undirected versions of the Poljak‐Rödl function
Authors: Tardif Claude , Wehlau David 
Published: August 2005

AbstractLet f(n) = min{χ(G × H) : G and H are n‐chromatic digraphs} and g(n) = min{χ(G × H) : G and H are n‐chromatic graphs}. We prove that f is bounded if and only if g is bounded. © 2005 Wiley Periodicals, Inc. J Graph Theory
Sperm structure and phylogeny of Astigmata
Authors: Liana Marcin , Witaliński Wojciech 
Published: August 2005

AbstractThe Astigmata, a large and variable group, is still a subject of taxonomic dispute. Particularly, their origin from ancestors of the lower oribatid mites (e.g., Malaconothroidea) seems well documented by many lines of evidence. The structure of spermatozoa has been successfully applied to phylogenetic investigations in many animal groups. The aim of our study was to provide new data on spermatozoon structure in Astigmata and to consider its appropriateness in phylogenetic studies. The study reveals information on spermatozoa in 17 species of Astigmata (11 species studied for the first time) extending our knowledge to 18 species (one species known only from the literature) representing 12 families and 7 superfamilies. Spermatozoa have the same basic structure in all species: cells are multiform and the chromatin forms thin threads embedded directly in the cytoplasm; the acrosome is absent. The cytoplasm in most species contains electron‐dense lamellae, varying in both number and arrangement within the cell. In Sarcoptoidea, electron‐dense tubules in contact with lamellae margins were also observed in Psoroptidae (Psoroptes equi), whereas in two representatives of Sarcoptidae (Notoedres cati and Sarcoptes scabiei), only electron‐dense tubules were found. In two species, Canestrinia sellnicki (Canestrinioidea: Canestriniidae) and Scutulanyssus obscurus (Analgoidea: Pteronyssidae), neither lamellae nor tubules were present. The mitochondria in a spermatozoon are usually gathered at the cell periphery and their structure is usually modified to form so‐called mitochondrial derivatives. The chromatin threads are an autapomorphy strongly supporting the monophyly of Astigmata. As spermatozoa vary considerably between species in Astigmata, we deduce that sperm structure may be useful for phylogenetic analyses within the group. Several conclusions concerning the affinities within Astigmata are presented. Spermatology seems to be unhelpful, however, in questions on the origin of Astigmata (particularly for Astigmata–Oribatida relationships), since their sperm do not possess synapomorphies with sperm of the remaining groups of Acariformes, i.e., Endeostigmata, Prostigmata, and Oribatida. J. Morphol. © 2005 Wiley‐Liss, Inc.
Formation of Core‐Shell‐Corona Micellar Complexes through Adsorption of Double Hydrophilic Diblock Copolymers into Core‐Shell Micelles
Authors: Zhang Wangqing , Shi Linqi , Gao Lichao , An Yingli , Wu Kai 
Published: August 2005

AbstractSummary: The complexation between polystyrene‐block‐poly(acrylic acid) (PS‐b‐PAA) micelles and poly(ethylene glycol)‐block‐poly(4‐vinyl pyridine) (PEG‐b‐P4VP) is studied, and a facile strategy is proposed to prepare core‐shell‐corona micellar complexes. Micellization of PS‐b‐PAA in ethanol forms spherical core‐shell micelles with PS block as core and PAA block as shell. When PEG‐b‐P4VP is added into the core‐shell micellar solution, the P4VP block is absorbed into the core‐shell micelles to form spherical core‐shell‐corona micellar complexes with the PS block as core, the combined PAA/P4VP blocks as shell and the PEG block as corona. A model is suggested to characterize the core‐shell‐corona micellar complexes.Schematic formation of core‐shell‐corona (CSC) micellar complexes by adsorption of PEG‐b‐P4VP into core‐shell PS‐b‐PAA micelles.imageSchematic formation of core‐shell‐corona (CSC) micellar complexes by adsorption of PEG‐b‐P4VP into core‐shell PS‐b‐PAA micelles.
Recovery of phase inconsistencies in continuously moving table extended field of view magnetic resonance imaging acquisitions
Authors: Kruger David G. , Riederer Stephen J. , Rossman Phillip J. , Mostardi Petrice M. , Madhuranthakam Ananth J. , Hu Houchun H. 
Published: August 2005

AbstractMR images formed using extended FOV continuously moving table data acquisition can have signal falloff and loss of lateral spatial resolution at localized, periodic positions along the direction of table motion. In this work we identify the origin of these artifacts and provide a means for correction. The artifacts are due to a mismatch of the phase of signals acquired from contiguous sampling fields of view and are most pronounced when the central k‐space views are being sampled. Correction can be performed using the phase information from a periodically sampled central view to adjust the phase of all other views of that view cycle, making the net phase uniform across each axial plane. Results from experimental phantom and contrast‐enhanced peripheral MRA studies show that the correction technique substantially eliminates the artifact for a variety of phase encode orders. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Continuous ASL (CASL) perfusion MRI with an array coil and parallel imaging at 3T
Authors: Wang Ze , Wang Jiongjiong , Connick Thomas J. , Wetmore Gabriel S. , Detre John A. 
Published: August 2005

AbstractThe purpose of this work was to assess the feasibility and efficacy of using an array coil and parallel imaging in continuous arterial spin labeling (CASL) perfusion MRI. An 8‐channel receive‐only array head coil was used in conjunction with a surrounding detunable volume transmit coil. The signal to noise ratio (SNR), temporal stability, cerebral blood flow (CBF), and perfusion image coverage were measured from steady state CASL scans using: a standard volume coil, array coil, and array coil with 2‐ and 3‐fold accelerated parallel imaging. Compared to the standard volume coil, the array coil provided 3 times the average SNR increase and higher temporal stability for the perfusion weighted images, even with threefold acceleration. Although perfusion images of the array coil were affected by the inhomogeneous coil sensitivities, this effect was invisible in the quantitative CBF images, which showed highly reproducible perfusion values compared to the standard volume coil. The unfolding distortions of parallel imaging were suppressed in the perfusion images by pairwise subtraction, though they sharply degraded the raw EPI images. Moreover, parallel imaging provided the potential of acquiring more slices due to the shortened acquisition time and improved coverage in brain regions with high static field inhomogeneity. Such results highlight the potential utility of array coils and parallel imaging in ASL perfusion MRI. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Homodyne reconstruction and IDEAL water–fat decomposition
Authors: Reeder Scott B. , Hargreaves Brian A. , Yu Huanzhou , Brittain Jean H. 
Published: August 2005

AbstractMultipoint water–fat separation methods have received renewed interest because they provide uniform separation of water and fat despite the presence of B0 and B1 field inhomogeneities. Unfortunately, full‐resolution reconstruction of partial k‐space acquisitions has been incompatible with these methods. Conventional homodyne reconstruction and related algorithms are commonly used to reconstruct partial k‐space data sets by exploiting the Hermitian symmetry of k‐space in order to maximize the spatial resolution of the image. In doing so, however, all phase information of the image is lost. The phase information of complex source images used in a water–fat separation acquisition is necessary to decompose water from fat. In this work, homodyne imaging is combined with the IDEAL (iterative decomposition of water and fat with echo asymmetry and least squares estimation) method to reconstruct full resolution water and fat images free of blurring. This method is extended to multicoil steady‐state free precession and fast spin‐echo applications and examples are shown. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Achieving sufficient spectral bandwidth for volumetric 1H echo‐planar spectroscopic imaging at 4 Tesla
Authors: Ebel Andreas , Maudsley Andrew A. , Weiner Michael W. , Schuff Norbert 
Published: August 2005

AbstractComplete coverage of the in vivo proton metabolite spectrum, including downfield resonances, requires a spectral bandwidth of approximately 9 ppm. Spectral bandwidth of in vivo echo‐planar spectroscopic imaging (EPSI) is primarily limited by gradient strength of the oscillating readout gradient, gradient slew rate, and limits on peripheral nerve stimulation for human subjects. Furthermore, conventional EPSI reconstruction, which utilizes even and odd readout echoes separately, makes use of only half the spectral bandwidth. In order to regain full spectral bandwidth in EPSI, it has previously been suggested to apply an interlaced Fourier transform (iFT), which uses even and odd echoes simultaneously. However, this method has not been thoroughly analyzed regarding its usefulness for in vivo 3D EPSI. In this Note, limitations of the iFT method are discussed and an alternative, cyclic spectral unwrapping, is proposed, which is based on prior knowledge of typical in vivo spectral patterns. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Whole‐body magnetic resonance imaging featuring moving table continuous data acquisition with high‐precision position feedback
Authors: Zenge Michael O. , Ladd Mark E. , Vogt Florian M. , Brauck Katja , Barkhausen Joerg , Quick Harald H. 
Published: August 2005

AbstractA novel setup for whole‐body MR imaging with moving table continuous data acquisition has been developed and evaluated. The setup features a manually positioned moving table platform with integrated phased‐array surface radiofrequency coils. A high‐precision laser position sensor was integrated into the system to provide real‐time positional data that were used to compensate for nonlinear manual table translation. This setup enables continuous 2D and 3D whole‐body data acquisition during table movement with surface coil image quality. The concept has been successfully evaluated with whole‐body steady‐state free precession (TrueFISP) anatomic imaging in five healthy volunteers. Seamless coronal and sagittal slices of continually acquired whole‐body data during table movement were accurately reconstructed. The proposed strategy is potentially useful for a variety of applications, including whole‐body metastasis screening, whole‐body MR angiography, large field‐of‐view imaging in short bore systems, and for moving table applications during MR‐guided interventions. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Understanding and optimizing the amplitude modulated control for multiple‐slice continuous arterial spin labeling
Authors: Utting Jane F. , Thomas David L. , Gadian David G. , Helliar Robert W. , Lythgoe Mark F. , Ordidge Roger J. 
Published: August 2005

AbstractMultiple‐slice perfusion imaging by continuous arterial spin labeling (CASL) is made possible by amplitude modulation (AM) of the labeling RF pulse, but perfusion sensitivity is reduced relative to the single‐slice technique. A computer model of the Bloch equations for velocity driven adiabatic fast passage was developed to elucidate the compromised sensitivity to perfusion of the AM control technique for CASL. Calculations were performed over ranges of RF pulse amplitude, B1; magnetic field gradient, G; phase, ϕ, and frequency, f, of the modulation function; velocity, v, and relaxation times, T1 and T2, of blood. It was found that unless f > 2πB1, ϕ determines the performance of the AM control; excessively high B1 or v reduces the efficiency of the AM control; and T1 relaxation dominates if f is too great. In vivo, in rat brain (n = 5) at 2.35 T, the sensitivity of the AM technique to perfusion was 70% of the sensitivity of single‐slice CASL. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Transverse relaxation of cells labeled with magnetic nanoparticles
Authors: Ziener C. H. , Bauer W. R. , Jakob P. M. 
Published: August 2005

AbstractWe describe the NMR relaxation properties of magnetically labeled cells. The cells are labeled with magnetic nanoparticles (SPIO, USPIO), which generate susceptibility contrast. The geometry of the labeled cells and the surrounding tissue is considered. We assume that the magnetic nanoparticles accumulate to form a magnetic core of radius RC inside the cell. The correlation time τ, which describes the motion of spins around this core, is analyzed. Using the strong collision approach, explicit expressions are derived for the transverse relaxation rate R for tissue containing labeled cells as a function of the core radius, the diffusion coefficient, and the concentration of the nanoparticles. The predictions of this model agree well with numerical simulations and experimental data. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.