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  • 1
    Publication Date: 2013-05-17
    Description: An ambitious goal in biology is to understand the behaviour of cells during development by imaging-in vivo and with subcellular resolution-changes of the embryonic structure. Important morphogenetic movements occur throughout embryogenesis, but in particular during gastrulation when a series of dramatic, coordinated cell movements drives the reorganization of a simple ball or sheet of cells into a complex multi-layered organism. In Xenopus laevis, the South African clawed frog and also in zebrafish, cell and tissue movements have been studied in explants, in fixed embryos, in vivo using fluorescence microscopy or microscopic magnetic resonance imaging. None of these methods allows cell behaviours to be observed with micrometre-scale resolution throughout the optically opaque, living embryo over developmental time. Here we use non-invasive in vivo, time-lapse X-ray microtomography, based on single-distance phase contrast and combined with motion analysis, to examine the course of embryonic development. We demonstrate that this powerful four-dimensional imaging technique provides high-resolution views of gastrulation processes in wild-type X. laevis embryos, including vegetal endoderm rotation, archenteron formation, changes in the volumes of cavities within the porous interstitial tissue between archenteron and blastocoel, migration/confrontation of mesendoderm and closure of the blastopore. Differential flow analysis separates collective from relative cell motion to assign propulsion mechanisms. Moreover, digitally determined volume balances confirm that early archenteron inflation occurs through the uptake of external water. A transient ectodermal ridge, formed in association with the confrontation of ventral and head mesendoderm on the blastocoel roof, is identified. When combined with perturbation experiments to investigate molecular and biomechanical underpinnings of morphogenesis, our technique should help to advance our understanding of the fundamentals of development.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4220246/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4220246/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Moosmann, Julian -- Ershov, Alexey -- Altapova, Venera -- Baumbach, Tilo -- Prasad, Maneeshi S -- LaBonne, Carole -- Xiao, Xianghui -- Kashef, Jubin -- Hofmann, Ralf -- R01 CA114058/CA/NCI NIH HHS/ -- R01 GM077288/GM/NIGMS NIH HHS/ -- England -- Nature. 2013 May 16;497(7449):374-7. doi: 10.1038/nature12116.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23676755" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Evolution ; Cell Movement ; Endoderm/embryology ; Gastrulation/*physiology ; Head/embryology ; Imaging, Three-Dimensional/instrumentation/methods ; Mesoderm/embryology ; Morphogenesis ; Movement ; Rotation ; Time Factors ; X-Ray Microtomography/instrumentation/*methods ; Xenopus laevis/anatomy & histology/*embryology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2011-07-02
    Description: The coxa-trochanteral joints on the legs of the weevil Trigonopterus oblongus (Pascoe) work as a biological screw-and-nut system. The apical portions of the coxae closely resemble nuts with well-defined inner threads covering 345 degrees . The corresponding trochanters have perfectly compatible external spiral threads of 410 degrees .〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉van de Kamp, Thomas -- Vagovic, Patrik -- Baumbach, Tilo -- Riedel, Alexander -- New York, N.Y. -- Science. 2011 Jul 1;333(6038):52. doi: 10.1126/science.1204245.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉ANKA-Institute for Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21719669" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Extremities/anatomy & histology/physiology ; Image Processing, Computer-Assisted ; Joints/anatomy & histology/physiology ; Movement ; Muscles/anatomy & histology/physiology ; Rotation ; Weevils/*anatomy & histology/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Keywords: COMBINATION ; Germany ; TOXICITY ; DRUG ; PATIENT ; treatment ; antibodies ; antibody ; TRIAL ; LYMPHOMA ; AGE ; EFFICACY ; SAFETY ; CHRONIC LYMPHOCYTIC-LEUKEMIA ; FOLLICULAR LYMPHOMA ; DENMARK ; NON-HODGKINS-LYMPHOMA ; AGENT ; GRADE ; fludarabine ; ANTI-CD20 MONOCLONAL-ANTIBODY ; AUTOIMMUNE HEMOLYTIC-ANEMIA ; CHOP ; INDOLENT ; LOW-GRADE LYMPHOMA ; rituximab ; thrombocytopenia
    Abstract: Fludarabine in combination with cyclophosphamide is an effective treatment for newly diagnosed as well as relapsed follicular lymphoma. The anti-CD20 antibody rituximab has been employed successfully for the same indications. No such data were available on a combined use of these agents. Therefore, we conducted a phase II study to evaluate the safety and efficacy of a combination of rituximab (375 mg/m(2)), fludarabine (4 x 25 mg/m(2)) and cyclophosphamide (1 x 750 mg/m(2)), for the treatment of relapsed follicular lymphoma. An unexpected, severe hematologic toxicity with significant, prolonged thrombocytopenias WHO grade III/IV in 6 (35%) of 17 patients treated in total occurred, leading to early termination of the trial. Cytologic and serologic analyses point toward a direct toxic effect. Older patients (mean age 64.7 vs. 56.5 yr) were significantly (P = 0.02) more likely to suffer from this toxicity, whereas no other clinical or hematologic parameter differed statistically between the patients suffering from thrombocytopenia and those who did not. The addition of rituximab to fludarabine/cyclophosphamide employed at doses given above in relapsed follicular lymphoma may have led to this increase in thrombocytopenias. Therefore, caution should be exercised when combining these drugs for the treatment of patients with relapsed follicular lymphoma, especially when treating older patients
    Type of Publication: Journal article published
    PubMed ID: 15347311
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  • 4
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Y2Co17(0001) was grown on W(110) by pulsed laser deposition. The structural and morphological features of the films as a function of substrate temperature and thickness were studied in situ by means of reflection high-energy electron diffraction, and ex situ by means of scanning electron microscopy, transmission electron microscopy, and x-ray analysis (diffraction and reflection). Different growth modes were observed depending on the experimental conditions. They are discussed by considering the kinetical properties of the deposit and the thermodynamical properties of the system. The magnetic properties of the films have been investigated and related to the structural analysis. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Synchrotron radiation has been used to measure the rocking curves from a (GaIn)(AsP) single layer grown on an InP (100)-oriented substrate. For angles of incidence ΦB = (ΘB − φ) ≤ 0.7° measured at the Bragg angle ΘB (φ is the angle between the diffracting lattice plane and the surface), the rocking curve (RC) is very strongly influenced by total external reflection (TER). This causes a decrease in the full width at half-maximum (FWHM) and an asymmetrical shape for the RC for small ΦB. Both of these effects are due to the Bragg-angle shift from the actual incident angle Φ which is not considered in the conventional dynamical theory. In this paper the essential influence of TER on any thin-layer rocking curve is investigated using a numerical solution of the extended dynamical theory. The pattern can be interpreted up to ΦB ≥ ΘC (ΘC is the angle of TER) by semiempirical incorporation of the results of the extended theory with the coupling formalism of Barrels, Hornstra & Lobeek [Acta Cryst. (1986). A42, 539–545].
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 1623-1625 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A GaAs surface grating (period 574 nm) is analyzed by four crystal-six reflection x-ray diffraction. Two-dimensional measurements in the vicinity of the 004 GaAs reciprocal lattice point show satellites in the transverse direction related to the periodicity of the grating. A cross pattern, centered on the 004 GaAs reciprocal lattice point, is formed by these satellites. An explanation is given by a model which includes the influence of transmission through the surface pattern on the substrate diffraction.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 21 (1988), S. 386-392 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The compositional depth profile in semiconductor heterostructures can be determined from X-ray diffraction patterns. Different grading profiles were studied through theoretical simulations with regard to their features in the rocking curve. It was found that the thickness and the grading of a particular layer cannot be determined independently of each other. A linear grading gives rise to an increased peak width of the layer diffraction peak whereas an exponential grading can be detected from the damping of high-order interference fringes. The exponential model can be applied to determine the abruptness of the heterointerfaces. The proposed evaluation method of experimental rocking curves includes the case of overlapping peaks of the layer and the substrate diffraction. The simulation results are discussed for a GaAs/Ga1−xAlxAs/GaAs[001] double heterostructure. When the experimental resolution is taken into account, the sensitivity of the interface width determination was 100–200 Å.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 3744-3758 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The surface shape and the spatial distribution of strain in GaInAs/InP multilayer gratings is experimentally determined by combining high-resolution x-ray diffraction and grazing-incidence diffraction. Dramatic deformations of the diffraction patterns in the measured reciprocal space maps of such gratings indicate a strongly nonuniform character of lattice distortions in the layers, caused by elastic strain relaxation. By coupling x-ray diffraction theory and elasticity theory within one single evaluation formalism, an experimental strain and shape analysis could be performed which was not yet available in this form by other methods. The different components of the strain tensor are determined by recording diffraction patterns around different reciprocal lattice points. We study how the strain relaxation of the multilayer grating evolves towards the free surface, and how the local strain distribution is modulated due to the compositional profile of the layered setup. Furthermore, the article describes in detail the effects of the grating shape, the multilayer morphology, and the lattice strain field on the diffraction patterns of multilayered gratings. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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