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  • 1990-1994  (21)
  • 1965-1969  (6)
  • 1960-1964  (3)
  • Life and Medical Sciences  (29)
  • phonon-assisted exciton lifetime reduction
  • 1
    Electronic Resource
    Electronic Resource
    The effect of lattice vibrations on trap-limited exciton lifetimes (1969)
    Springer
    Journal of statistical physics 1 (1969), S. 253-269 
    Details
    ISSN: 1572-9613
    Keywords: trap-limited exciton lifetimes ; asymmetrical random walks ; lattice vibrations ; displacement correlation functions ; phonon-assisted exciton lifetime reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The problem of exciton migration and trapping on a linear polymer is treated as a random walk on a one-dimensional lattice. The average number of steps required for a walker to be trapped is calculated when the probability of stepping to adjacent lattice sites is not symmetrical, and is found to be less than that calculated for a symmetrical walk. An asymmetrical stepping probability is shown to result from the thermal vibrations of the lattice. The magnitude of this effect on the exciton lifetime is estimated and found to be significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007480
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  • 2
    Electronic Resource
    Electronic Resource
    Some histochemical and biochemical observations on the lymphatic tissues of highly inbred white Leghorns (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 281-301 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Lymphatic tissues of inbred lines of White Leghorn chickens and 20-day embryos (inbreeding coefficient exceeds 95%) were used in the experiments, e.g. line 6 was susceptible, line 7 was resistant, and line 15 I was intermediate in response to the virus. Enzyme reactions were studied in cryostat-cut sections of tissues and in tissue minces by colorimetric procedures. Numbers of isozymes and proteins of lymphatic tissues were resolved by disc gel electrophoresis.Colorimetric tests showed that intensities of lactate, malate, isocitrate and succinic dehydrogenase catalyzed reactions were higher in the bursae of 15 I 20-day embryos than they were in bursae of either line 6 or 7 embryos. Intensity of dehydrogenase reactions of the spleen (15 I embryos) exceeded that found in line 6 and 7 embryos. Intensity of diaphorase reactions in the spleen and thymus was fairly uniform in all lines of embryos. Intensity of DPN diaphorase reactions in the bursae of line 15 I embryos exceeds that found in either line 6 or 7 embryos. Intensity of enzyme reactions leveled off to become fairly uniform in lymphatic tissues of chickens 3-4 weeks post hatching with the exception that dehydrogenase reactions were less intense in the thymus of 15 I chickens.Photodensitometer scans of acrylamide gel columns showed that proteins of line 6 lymphatic tissues combined with less Amido black 10B than lymphatic proteins of either line 15 I or 7 embryos. There was fairly good agreement between concentrations of strong mobility (components 1-9) and weak mobility (components 10-16) in lymphatic tissues of all lines of embryos with the exception that strong mobility proteins were about twice as concentrated in line 15 I bursae. Variable numbers of lactate isozymes were found in the lymphatic tissues of 20-day embryos.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051250303
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  • 3
    Electronic Resource
    Electronic Resource
    The fine structure of daphnid supraesophageal and optic ganglia, and its possible functional significanceThis research was supported in part by National Science Foundation grant GB-3960; the assistance of Electron Microscope Laboratory staff at Washington State University is gratefully acknowledged. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 126 (1968), S. 373-393 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Neurosecretory activity and fine structure of the supraesophageal and optic ganglia of Daphnia schødleri Sars were studied. The relative amount of paraldehyde fuchsin stainable material present was determined at “daylight” and at one and three hours following for animals maintained under photoperiods of 7.5, 10.5, 13.5, and 16.5 hours. More material was found after one hour in both ganglia and there was a tendency for more in the optic ganglion under 7.5- and 10.5-hour photoperiods.Sections made at two levels in the supraesophageal ganglion and one level in the optic ganglion were examined with an electron microscope. Posterior and anterior parts of the supraesophageal ganglion contain apparent nerve processes at the edge of the ganglion, parallel to the anterior-posterior axis; these have large granules. Neurons in both areas contain patches of presumed polysaccharide granules. In the posterior region are a dorsolateral and a ventrolateral glandular cell, presumably these occur on both sides of the brain. They have very well-developed endoplasmic reticulum and some large granules. The dorsal cell is usually at the tip of a glial attenuation.Concentric lamellar systems are located in dilated nerve processes of the first optic ganglion neuropile. Large whorls (about 3.5 μ) are composed of concentric lamellae. When lamellae do not form complete rings, they end in loops or in dilated tubules that are sometimes constricted as vesicles. Small whorls (1.5 μ) typically have lamellae joined into two or three thick layers. Mitochondria are frequently associated with the whorls. It is proposed that the whorls are active in synthesis, possibly neurohumor production.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051260402
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  • 4
    Electronic Resource
    Electronic Resource
    Some histochemical observations on the effects of chorioallantoic grafts on the spleen, bursa, and peripheral blood of chicken embryos (1966)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 149-165 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hatching eggs from inbred lines of chickens (inbreeding coefficient exceeds 95%) which show various degrees of resistance and susceptibility to Rous sarcoma, were used for experimentation. Adult tissues were grafted onto the chorioallantois on the tenth day of incubation and tissues of host and control embryos were harvested on the twentieth day of incubation. Enzymes were localized in tissues by histochemical procedures.Small pieces of tissue (thymus or bursa), when grafted onto the chorioallantois, increased the size of the spleen in host embryos although splenomegaly did not invariably occur. Two types of reactions were observed in the spleen, i.e., enlarged spleens with cysts or enlarged spleens which from a morphological point of view were normal. Grafts of either thymus or bursa decreased the size of the host embryo's bursa or were without effect. When weight of the bursa of host embryos was significantly less than that of control embryos on the twentieth day of incubation, this size relationship persisted in chicks four weeks post hatching.Intensity of dehydrogenase and acid phosphatase reactions in cysts of enlarged spleens and in the multinucleated giant cells investing them suggests that they consist of groups of degenerating cells. Intensity of enzyme reaction indicates that enlarged spleens of host embryos in which cysts were absent were normal. Enzyme reactions in the bursae of experimental embryos were more intense than those identified in the same tissues of control embryos. Catabolic reactions were the predominant type in grafts ten days subsequent to implantation. Grafts increased the number of erythrocytes in the peripheral blood of host embryos.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051180202
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  • 5
    Electronic Resource
    Electronic Resource
    Reorganization of cytoskeletal and junctional proteins during cochlear hair cell degeneration (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 18 (1991), S. 215-227 
    Details
    ISSN: 0886-1544
    Keywords: guinea pig ; organ of Corti ; cytokeratins ; actin ; cingulin ; phalangeal scar ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Experiments were carried out to elucidate changes in cytoskeletal elements and intercellular junctions in the organ of Corti, when hair cells degenerate and phalangeal scars form. Hair cell damage was induced by exposing guinea pigs to high intensity noise. The spatial and temporal changes in the organization of micro-filaments, intermediate filaments, and tight junction-specific proteins were investigated using scanning and transmission electron microscopy and histochemistry. The results show that microfilaments, cytokeratins, adherens junctions, and tight junctions rearrange their distribution in damaged areas. From the temporal sequence of these changes it appears that phalangeal scars develop simultaneous with hair cell degeneration, and that the integrity of the luminal membranes in the organ of Corti is not interrupted. Each scar is formed by two supporting cells which expand and invade the sub-apical region of the dying hair cell. This region becomes cytokeratin-positive. The two supporting cells meet at the mid-line of the scar, where a new junctional complex is formed. The junctional complex consists of tight junction and adherens-type junction, but desmosomes are absent.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970180307
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  • 6
    Electronic Resource
    Electronic Resource
    Metabolic regulation in mammalian sperm: Mitochondrial volume determines sperm length and flagellar beat frequency (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 19 (1991), S. 180-188 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; cilia and flagella ; mechanochemical transduction ; dynein ; cell motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the absence of glycolytic support, mammalian sperm derive their energy for motility from a densely packed array of mitochondria at the base of the flagellum known as the midpiece. Using data on the morphometric dimensions of over 200 mammalian species, we found that an allometric relationship exists between midpiece length (Lm) and flagellum length (Lf). Specifically, the length of the midpiece varies approximately as the 3/2 power of the flagellar length although the proportionality constant is different for eutherian and marsupial sperm. In contrast, when we corrected for the fraction of the midpiece that was taken up by mitochondria, a single linear correlation between mitochondrial volume and flagellar length for all mammals was found. These allometric relationships were used along with basic flagellar hydrodynamic theories to establish a unifying equation that predicted flagellar frequencies for any mammalian sperm between 40 μm and 200 μm in length. These findings imply that, at least in mammals, the mechanisms for energy production and dissipation in sperm flagella are highly conserved.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970190306
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  • 7
    Electronic Resource
    Electronic Resource
    A multiplanar anatomic study of the cervical proximal nerve roots and spinal nerves (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 5 (1992), S. 433-440 
    Details
    ISSN: 0897-3806
    Keywords: anatomy ; spine ; sheath ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An anatomic study focused on the proximal cervical spinal nerves has not been reported. Therefore, we dissected the cervical spinal nerves of three cadavers and examined stained sections in parasagittal and axial planes through the proximal cervical spinal nerves and root sheaths. These studies documented distinct segments of the spinal nerve which had not been completely described in the previous anatomic studies. The sheath originates from the dural sac as a common sleeve, divides into two sleeves, one containing the ventral root and one the dorsal root, and then distal to the dorsal root ganglion fuses again into one sleeve. A space, the interradicular cleft, separates the dorsal and ventral portions of the sleeve. The proximal segment of the spinal nerve proper distal to the dorsal root ganglion is composed of multiple small fascicles surrounded by a dense epineurium. The presence of an interradicular cleft in the cervical nerve root sheath and of fascicles in the cervical spinal nerve has significance for imaging of the cervical spinal nerves and for the pathogenesis of symptoms in cases of partial compression. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ca.980050603
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  • 8
    Electronic Resource
    Electronic Resource
    Growth factors and wound repair (1991)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 46 (1991), S. 1-2 
    Details
    ISSN: 0730-2312
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240460102
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  • 9
    Electronic Resource
    Electronic Resource
    Molecular physiology of amylin (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 19-28 
    Details
    ISSN: 0730-2312
    Keywords: amylin ; calcitonin ; CGRP ; cAMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Amylin is a 37-amino acid peptide first isolated, purified, and characterized from the amyloid deposits in the pancreases of type 2 diabetics. It is synthesized and secreted primarily from pancreatic beta cells along with insulin. The ability of amylin to potently reduce insulin-stimulated incorporation of glucose into glycogen in skeletal muscle requires both an intact 2Cys-7Cys disulfide bond and a COOH-terminal amide. Amylin has structural and functional relationships to two other messenger proteins, calcitonin and CGRP. Amylin has relatively potent calcitonin-like activity on bone metabolism and weaker CGRP-like activity on the vasculature. CGRP is a slightly weaker agonist than amylin for metabolic responses. Although rat calcitonins are weak, teleost fish calcitonins are very potent agonists for amylin's metabolic effects. This group of peptides appears to act on a family of related G protein-coupled receptors; several variant calcitonin receptors have recently been cloned and expressed. These receptors appear to be coupled to adenylyl cyclase in many instances; recent evidence supports the view that amylin's effects on skeletal muscle occur, at least in large part, through activation of the cAMP pathway. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240550004
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  • 10
    Electronic Resource
    Electronic Resource
    The skin of primates XI. The skin of the white-browed gibbon (Hylobates Hoolock)This work was supported by grants from the United States Public Health Service, RG-2125(C12), Colgate-Palmolive Company, and Chesebrough-Pond's, Inc. (1962)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 143 (1962), S. 169-177 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091430210
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