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  • 2020-2024
  • 1975-1979  (10)
  • 1950-1954  (2)
  • Life and Medical Sciences  (9)
  • Photosynthesis  (2)
  • 13-trisomy  (1)
  • 1
    Electronic Resource
    Electronic Resource
    The early history of oxygen and ozone in the atmosphere (1978)
    Springer
    Pure and applied geophysics 117 (1978), S. 498-512 
    Details
    ISSN: 1420-9136
    Keywords: History of atmosphere ; Oxygen ; Ozone ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract There may have been three stages in the growth of oxygen in the terrestrial atmosphere. Prior to the origin of photosynthesis the only source of oxygen was photolysis of water vapor followed by escape of hydrogen to space. The rate of this process was probably less than the rate of release of reduced gases (principally hydrogen) from volcanoes, so the oxygen partial pressure was held to negligibly low values by photochemical reactions with an excess of hydrogen. The photosynthetic source of oxygen was probably in operation as long ago as 3.8 billion years. It released oxygen to the ocean. Presumably most of this oxygen was destroyed in the ocean as long as its rate of supply was less than the rate of supply of readily oxidizable material (principally Fe2+) provided by the weathering of rocks. This phase appears to have lasted until about 2 billion years ago, during which period most banded iron formations were deposited. During this period the production of oxygen by algae was limited by competition with photosynthetic bacteria, which preempted the supply of nutrient phosphorus as long as reduced chemicals were available in the environment. Once the photosynthetic oxygen source exceeded the rate of supply of reduced minerals exposed by erosion and weathering, the accumulation of oxygen in the ocean and atmosphere could be controlled only by reaction of oxygen with reduced organic material. This is the stabilization mechanism that operates today. It seems unlikely that oxygen could be consumed at a significant rate by this process until oxygen levels sufficiently high to support respiration had been achieved. I therefore suggest that atmospheric oxygen rose rapidly from essentially zero to approximately its present value (within a factor of 10) when the photosynthetic source of oxygen rose above the weathering source of reduced minerals, probably about 2 billion years ago. The ozone layer and the ultraviolet screen were absent prior to this time and essentially fully developed after this time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876630
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen and hydrogen in the primitive atmosphere (1978)
    Springer
    Pure and applied geophysics 116 (1978), S. 222-231 
    Details
    ISSN: 1420-9136
    Keywords: Photolysis ; Photosynthesis ; Primitive Atmosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract From time to time there appears in the literature the assertion that photolysis of water vapor could have maintained an appreciable concentration of oxygen in the primitive (prebiological) atmosphere. The implausibility of this assertion is argued in this paper. By itself, photolysis does not provide a source of oxygen because it is usually followed by recombination of the products of photolysis. Only the escape to space (at a much smaller rate) of the hydrogen produced by photolysis of water results in a net source of oxygen. The oxidation state of the primitive atmosphere depended on the relative magnitudes of this net source of oxygen and a volcanic source of hydrogen and other reduced gases. Today the volcanic source of reduced gases is approximately equal to the oxygen source provided by photolysis followed by escape. The oxygen source depends on the mixing ratio of water vapor in the stratosphere, which ultimately determines the rate of escape of hydrogen produced from water vapor. Its magnitude may not have been very different in the past. The volcanic source of hydrogen, on the other hand, is likely to have been much larger when the earth was tectonically young. Hydrogen was therefore released to the primitive atmosphere more rapidly than oxygen, probably. Photochemical reactions with the excess hydrogen maintained oxygen mixing ratios at negligibly small levels. The hydrogen mixing ratio was determined by a balance between the volcanic source (reduced by recombination with oxygen) and escape to space. In time, either because of decline of the volcanic source of hydrogen or because of addition of a biological source of oxygen, the input of oxygen to the atmosphere rose above the input of hydrogen. The oxidation state of the atmosphere changed rapidly. Volcanic hydrogen was now consumed by photochemical reactions with excess oxygen, while the oxygen mixing ratio was determined by a balance between the source (reduced by recombination with volcanic hydrogen) and consumption in reactions with reduced material at the surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01636879
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  • 3
    Electronic Resource
    Electronic Resource
    Eye findings in the 13 trisomy syndrome (1977)
    Springer
    European journal of pediatrics 124 (1977), S. 179-183 
    Details
    ISSN: 1432-1076
    Keywords: 13-trisomy ; Microphthalmia ; Coloboma ciliary body ; Cataracts ; Retinal detachment ; Retinal dysplasia ; Proliferation of pigment epithelium ; Calcified drusen ; Fibrocartilaginous dysplasia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The gross and microscopic eye findings in the first historic case of the 13-trisomy syndrome included: severe microphthalmia, coloboma of the ciliary body, cataracts, detached retina, and retinal dysplasia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00452109
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Sexual differences in the effects of castration on body and thymus weights in albino rats (1953)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 116 (1953), S. 237-246 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091160210
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  • 5
    Electronic Resource
    Electronic Resource
    Transfer of estrogens between rats united in parabiosisSupported in part by a grant from the University of Illinois Research Board, the Graduate College. (1954)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 119 (1954), S. 187-211 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091190205
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Development of the urostyle during metamorphosis in five species of anurans (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 311-329 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Normal development of the urostyle is described during late stages of metamorphosis in five species of anurans: Xenopus laevis (Daudin), Bufo americanus Holbrook, Pseudacris triseriata (Wied), Hyla chrysoscelis Cope, and Rana pipiens Schreber. The developing urostyle of all five species is composed of essentially the same cartilaginous elements: one pair of basidorsals above the notochord and the subtended hypochord. Among the five species there is variation in such details as the number of spinal nerve foramina and the degree of fusion of the basidorsals; however, both the hypochord and basidorsals are very similar in all five genera examined. Consideration of the literature suggests that contradictory descriptions of the developing urostyle result from (1) varied methods of study (alizarin-staining of whole specimens or serial cross-sections), (2) the variety of species examined, and (3) the particular stage of development of the tadpole described by an investigator.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051590303
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    A comparative radioautographic study of chondrocytic proliferation in nasal septal cartilage of the 5-day-old rat, rabbit, guinea pig and beagleThis investigation was supported in part by USPHA Program Project Grant DE 00853 from the National Institute of Dental Research, Bethesda, Maryland. (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 154 (1979), S. 437-445 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Growth sites within the cartilaginous nasal septa of four different species of animals (5-day-old rats, rabbits, guinea pigs and beagles) were identified by monitoring cellular proliferation radioautographically. A statistical analysis (MANOVA) was employed. It showed that, of the six combinations compared (rat-beagle, rat-guinea pig, rat-rabbit, beagle-guinea pig, beagle-rabbit, and guinea pig-rabbit), in only one (beagle-guinea pig) was there any similarity in growth pattern. The other five combinations all were significantly different. Since no particular areas emerged, with any consistency, as common growth sites within any of the four kinds of septa, it was concluded that the nasal septum might well play a passive role in midfacial growth, rather than an active role as previously thought.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001540308
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  • 8
    Electronic Resource
    Electronic Resource
    A radioautographic study of chondrocytic proliferation in nasal septal cartilage of the newborn rat This investigation was supported in part by USPHA Program Project Grant DE 00853 from the National Institute of Dental Research, Bethesda, Maryland. (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 150 (1977), S. 559-563 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Growth sites within the newborn cartilaginous nasal septum have been identified by monitoring chondrocytic proliferation radioautographically. Tritiated thymidine was the labeling agent used. The results were tabulated and charted graphically; they showed the overall septum to be relatively active mitotically, yielding an average of 3.54 labeled cells per microscopic field counted. However, certain areas showed greater activity than others, namely the anterior tip (4.51 labeled cells/field), the midportion (3.98 labeled cells/field) and the posterior section of the presphenoidal tail (4.24 labeled cells/field).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001500405
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  • 9
    Electronic Resource
    Electronic Resource
    Somatostatin-containing neurons in the rat brain: Widespread distribution revealed by immunocytochemistry after pretreatment with pronaseAided by USPHS Research Grants HD 10306 and ES01104, by the North Carolina United Community Services, and by the Neurobiology Program, University of North Carolina, Chapel Hill. (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 153 (1978), S. 483-488 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Immunocytochemical staining after controlled proteolytic treatment of the sections with pronase revealed widespread distribution of neuronal cell bodies with somatostatin- like immunoreactivity (SLI) in the rat forebrain. SLI-positive neurons were found in regions of the neocortex, the pyriform cortex, the cingulate cortex, the striatum, the olfactory tract and tubercle, the nucleus accumbens, the septum, and the hypothalamus. These results are consistent with previous radioimmunoassay findings and suggest the presence of large somatostatin-like (possibly precursor) molecules in the neurons stained for SLI after pronase treatment.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001530312
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  • 10
    Electronic Resource
    Electronic Resource
    The effects of various hormones on the surface morphology of testicular cells in culture (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 151 (1978), S. 55-69 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The purpose of this investigation was to study the effects of various hormones on the surface morphology of 20-day-old rat testicular cells in culture. Aggregates containing primarily Sertoli cells and germinal cells were obtained by enzymatic digestion. The surface morphology of the cells composing these aggregates was characterized under various culture conditions using light microscopy and scanning electron microscopy. The cytoplasmic processes of Sertoli cells became highly branched and filamentous after being cultured in the presence of rat, human or ovine FSH. Identical branching and filamentation was observed when Sertoli cells were cultured in rat TSH. Finally, numerous large blebs were observed on the surfaces of germinal cells cultured in the presence of insulin.These results suggest that the branching and filamentation of Sertoli cell cytoplasm observed after FSH stimulation are not specific for that hormone.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001510106
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