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  • 1
    Electronic Resource
    Electronic Resource
    Flavonoids from Virola calophylloidea (1987)
    s.l. : American Chemical Society
    Journal of natural products 50 (1987), S. 1045-1047 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50054a005
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  • 2
    Electronic Resource
    Electronic Resource
    Conformational Analysis of Achillin and Leukodin (1988)
    s.l. : American Chemical Society
    Journal of natural products 51 (1988), S. 221-228 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50056a005
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  • 3
    Electronic Resource
    Electronic Resource
    Cell shape and cytoskeletal organization of the endothelial cells of the semilunar heart valves in the developing chick (1986)
    Springer
    Anatomy and embryology 174 (1986), S. 83-89 
    Details
    ISSN: 1432-0568
    Keywords: Endothelial cells ; Cytoskeleton ; Semilunar valves ; Heart morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The composition and arrangement of the cytoskeletal elements of the endothelium of the semilunar valves have been studied in the embryonic chick heart during the stages 30 to 38. Microtubules, vimentin intermediate filaments and actin microfilaments were constant components of the valvular endothelial cells in the studied stages. Scanning electron microscopy after Triton-X-100 extraction revealed significant differences in the tridimensional arrangement of the cytoskeleton in the course of valve development. In the ventricular face of the cusps the cytoskeletal elements displayed a progressive longitudinal alignment, while in the arterial face of the cusps the cytoskeleton maintained the appearance of a network. Transmission electron microscopy revealed that these differences were especially prominent for vimentin intermediate filaments, although a similar tendency was also observed for microtubules. Microfilaments were scarce in the endothelial cells of both faces of the cusps, and the stress fibers typical of the endothelial cells of the adult valves were not observed in the embryonic material. The significance of these results in valve morphogenesis and histogensis and a possible linkage with differences in the local characteristics of the blood flow are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318339
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  • 4
    Electronic Resource
    Electronic Resource
    Glioblast migration in the optic stalk of the chick embryo (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 79-85 
    Details
    ISSN: 1432-0568
    Keywords: Optic stalk ; Optic fibers ; Axonal fascicles ; Glioblasts ; Cell migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopy was used to study the chick embryo optic stalk from Hamburger and Hamilton stages 21 to 29. Observations of glioblast morphology in different developmental stages suggest that these cells undergo radial migration toward peripheral regions of the stalk. Immediately previous to and during migration, morphological changes were noted in the glioblasts, including the appearance of lateral prolongations which contribute to the subdivision of optic fiber fascicles and the radial elongation of their nucleus, which gives the impression of squeezing itself into the peripheral glioblastic prolongation. These phenomena occur in a retino-diencephalic direction, commencing in the distal optic stalk during stage 23 and continuing in subsequent stages. The significance of glioblastic migration is discussed in relation to possible mechanisms through which optic fiber fascicles, initially located on the surface of the stalk, come to lie in deeper areas of the stalk wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309755
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of colchicine administration on the endothelial cells of the developing semilunar heart valves of the chick embryo (1987)
    Springer
    Cell & tissue research 250 (1987), S. 595-598 
    Details
    ISSN: 1432-0878
    Keywords: Endothelial cells ; Heart morphogenesis ; Semilunar valves ; Colchicine ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Recent ultrastructural studies have revealed that differences exist in endothelial cell shape and cytoskeletal architecture between the arterial and ventricular faces of developing semilunar valves. In the present work we analyzed the morphologic response of the valvular endothelial cells of chick embryos to colchicine by light microscopy, scanning electron microscopy and transmission electron microscopy. The results show that colchicine administration during the stages of valve morphogenesis causes a very conspicuous disruption of the endothelial layer of the arterial face of the valves. The cells appear rounded and show massive surface blebbing. These alterations were not present in the endothelial cells on the ventricular face of the valves at the same stages. On the basis of these results we suggest that a difference in the degree of cell differentiation exists between the endothelial cells of the arterial and ventricular faces of the cusps and that this difference may have morphogenetic significance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218952
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  • 6
    Electronic Resource
    Electronic Resource
    Extra-axonal environment and fibre directionality in the early development of the chick embryo optic chiasm: A light and scanning electron microscopic study (1987)
    Springer
    Journal of neurocytology 16 (1987), S. 299-310 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The events that occur during the early development of the optic chiasm of the chick embryo have been studied by light and scanning electron microscopy. In developmental stages previous to the arrival of the first optic fibres in the floor of the diencephalon, as well as during the arrival of the leading fibres, extracellular spaces can be seen in the diencephalon ventral wall. These spaces are defined by external cell prolongations which end in a foot-shaped formation. During stages 25 and 26 a prechiasmic degenerative centre appears in the area immediately rostral to the early chiasm, leading to a notable degree of disorganization in the diencephalon wall. This centre appears to be related to the reorganization of the system of external cell processes and extracellular spaces which become progressively more irregularly distributed, coinciding with the arrival of the first optic fibre fascicles to the midline of the floor of the diencephalon. The optic fibre fascicles change their latero-medial directionality in the medial-most regions of the ventral diencephalon, where their course becomes rostrocaudal. This reorientation of the optic fibres seems to be mediated by primitive glial cells which first appear in the ventrorostral region of the early chiasm (previously occupied by the system of external cell processes and extracellular spaces) in stage 26, increasing in number from this stage on. The morphology of the primitive glial cells is laminar in nature and the cells are seen to be densely packed together with no large extracellular spaces between them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01611342
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  • 7
    Electronic Resource
    Electronic Resource
    The structure of27Al (1988)
    Springer
    The European physical journal 331 (1988), S. 409-432 
    Details
    ISSN: 1434-601X
    Keywords: 27.30.+ t ; 21.10.HW ; 21.60.Cs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Gamma decay modes and spin assignments of levels in27Al have been investigated by proton-γ-ray angular correlation measurements in the24Mg(α, pγ) reaction at 14.2, 15 and 15.6 MeV bombarding energy and byγ-ray angular distribution measurements on the Ep=1820, 2114, 2293 and 2574 keV resonances of the26Mg(p, γ) reaction. Unique spin assignments were obtained as follows: I=3/2 for the 5827 keV state, I=5/2 for the 6115, 6465, 6765, 7577, 7721, 8097, 8136, 8324 keV states, I=7/2 for the 5433, 6533, 7413, 8037, 8442, 8586 keV states, I=9/2 for the 5418, 6512, 6713, 7997 keV states, I=11/2 for the 5500, 6948, 7400, 8396 keV states. The level scheme and electromagnetic properties of levels are compared with the results of shell model calculations which use the complete configuration space of the 0d5/2-1s1/2-0d3/2 shell and the unifieds-d shell Hamiltonian. The agreement is good to excellent and extends into the region of high level density above 7 MeV excitation energy. The total B(M1↑) below 8.5 MeV excitation energy is evaluated, using published resonance fluorescence and (e, e′) data, and quenching relative to the free-nucleon predictions is reexamined. Evidence in favour of a prolate ground state deformation of27Al and implications of this work for the astrophysically interesting26Al(p, γ) reaction are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01291900
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  • 8
    Electronic Resource
    Electronic Resource
    Salt tolerance of four tomato hybrids (1987)
    Springer
    Plant and soil 97 (1987), S. 233-241 
    Details
    ISSN: 1573-5036
    Keywords: Blossom-end rot ; Fruit quality ; Fruit yield ; Leaf mineral composition ; Tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A greenhouse lysimeter experiment was conducted to evaluate the response of tomato hybrids to varying levels of salinity. Four tomato hybrids F-172, F-150, Bornia and Diego were grown at four salinity levels. The soil was salinized prior to transplanting by irrigating with waters that were prepared by adding NaCl to the tap water. The electrical conductivities of the irrigation waters were 1.8, 4.5, 7.0, and 9.5 dS/m at 25°C. Yield, fruit quality, and leaf mineral composition were measured. Fifty percent fruint yield reduction for all hybrids was associated with a soil salinity of 5.1 dS/m. Each unit increase in salinity above 2 dS/m reduced yield by 14%. This indicates that these tomato hybrids are more salt sensitive than the older varieties. Fruit quality and leaf mineral composition were also affected by salinity and hybrid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374946
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  • 9
    Electronic Resource
    Electronic Resource
    Morphogenesis of the prehensile autopodium in the common chameleon (Chamaeleo Chamaeleo) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 187-194 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This report documents the development of the autopodium of the common chameleon (Chamaeleo chamaeleo) using light microscopy, scanning electron microscopy, and transmission electron microscopy. Three main periods were distinguished during the morphogenesis of this structure. In the first period (stages 33-35 of chameleon development) the autopodium is paddle-shaped with a prominent apical ectodermal ridge (AER) along the distal margin. During this period the AER has structural features similar to other reptilian and avian vertebrates except for the scarcity or absence of gap junctions. The second period of autopodium morphogenesis (stage 36 of chameleon development) is characterized by the formation of a central cleft which divides this structure into two digital segments. In the forelimb the autopodial cleft occupies the space between digits 3 and 4. In the hindlimb the cleft occupies the space between digits 2 and 3. Mesenchymal cell death constitutes a constant feature during cleft formation. In addition to cell death during this process, we have observed that the AER flattens out in the zone of cleft formation while in the digital portions of the autopodium it takes on a polystratified appearance. In the last period of autopodial morphogenesis (stage 37 of chameleon development) digits become free by means of interdigital mesenchymal cell death.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051940207
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