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  • 1
    Electronic Resource
    Electronic Resource
    A stochastic model and a Monte Carlo simulation for the description of CO oxidation on Pt/Sn alloys (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 5037-5044 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this paper we study CO oxidation on a catalyst consisting of a Pt/Sn alloy. On this catalyst the reaction can take place at room temperature. We use for the description two basically different methods: Monte Carlo simulations and a theoretical stochastic ansatz. The stochastic ansatz introduced recently [Mai, Kuzovkov, and von Niessen, Physica A 203, 298 (1994)] is a general method for the description of surface reaction systems including mono- and bimolecular steps. Using the Markovian behavior of these systems we formulate this ansatz in terms of master equations. It turns out that the stochastic ansatz can be used as an interesting and advantageous alternative to the standard Monte Carlo simulations. The particles involved in the reaction system have different tendencies toward building structures on the surface. The coverages show a strong dependency, not only on the composition of the gas phase but also on the initial concentration of the reaction promotor OH and the concentration of Pt sites in the catalyst material. The reaction probability does not influence the qualitative trends of the coverages versus the gas phase concentration of CO. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469553
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  • 2
    Electronic Resource
    Electronic Resource
    Exact enumeration of all conformations of a heteropolymer chain in a prescribed, non-compact volume (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 7829-7833 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We study the protein structure problem in a prescribed, non-compact volume (with a hole). The choice of such a volume offers the advantage of being closer in structure to real proteins. Using an exact enumeration technique we investigate the thermodynamic properties of the chain's configurations. These findings are compared to the results obtained for fully compact structures, such as the 3×3×3 cube. Interestingly we find here deviations from the random energy model. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473741
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  • 3
    Electronic Resource
    Electronic Resource
    Developmental expression of the CD15-epitope in the brainstem and spinal cord of the mouse (1997)
    Springer
    Anatomy and embryology 196 (1997), S. 13-25 
    Details
    ISSN: 1432-0568
    Keywords: Key words FAL ; Cell-cell interaction ; Inferior olive ; Red nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The expression of the 3-fucosyl-N-acetyl-lactosamine (FAL, CD15, Lex) epitope has been examined immunohistochemically in paraffin sections of the brainstem of the mouse. The initial appearance of labelling was at embryonic day (E)11, when immunoreactivity of radial glial fibres was noted in the medulla, pons and dorsal isthmus, while the spinal cord was immunoreactive from E12. Labelling remained faint until E14, when a distinctive radial pattern appeared in the medulla, pons and spinal cord. Immunoreactivity at E14 in both the spinal cord and medulla was strongest in a band in line with the sulcus limitans, passing ventrolaterally through the nucleus of the solitary tract in the case of the medulla. In both the spinal cord and the medulla, CD15 immunoreactivity divided the brainstem into radially arranged compartments, with an immunonegative paramedian region, strongly labelled ventrolateral segments, and moderately labelled lateral regions. Labelling of midline radial fibres was also apparent in the ventral mesencephalon at E14. After E18, labelling appeared in the paramedian region of the medulla, in particular around the inferior olivary nucleus, and gradually adopted a tufted appearance throughout the brainstem. Several regions of the developing brainstem showed specific labelling during fetal life. Distinct labelling of the developing red nucleus was visible from E15 to the time of birth, while some longitudinal bands of labelling were noted in the deeper layers of the superior colliculus from E17 until postnatal day (P)2. The adult pattern of immunolabelling was achieved by the end of the second postnatal week. The striking concentration of CD15 along the sulcus limitans of both the spinal cord and brainstem may serve to demarcate and separate dorsal (sensory) and ventral (motor) columns in a similar fashion to Pax gene expression. The precise timing of transient CD15 expression in the developing inferior olive and red nucleus is suggestive of a role for this epitope in developmental events of those structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050076
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  • 4
    Electronic Resource
    Electronic Resource
    Expression of the CD15 differentiation antigen in the reproductive tract of the female rat during fetal and early postnatal ontogeny (1997)
    Springer
    Histochemistry and cell biology 108 (1997), S. 57-66 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The expression of the (α1→3)-fucosyl-N-acetyl-lactosamine (CD15) epitope in the genital tract of the female rat during fetal and early postnatal ontogeny was investigated by means of immunohistochemistry. CD15 was exclusively associated with epithelial cells and was mainly located along the cell membrane. The CD15 expression was characterized, firstly, by considerable differences within the various structures and even substructures of the genital tract and secondly, by the high degree of time-related changes which accompanied the morphological development. In the Müllerian duct, CD15 was present from embryonic day (E) 14 until birth on the apical membranes throughout the epithelial cell layer. In the Wolffian duct, CD15 expression was present between E16 and E19. Along the longitudinal extent of the Wolffian duct, expression intensity differed, showing moderate to high levels in the epithelial cells of the cranial and caudal parts, but without recognizable CD15 expression in the intermediate part. In the urogenital sinus, CD15 was expressed from E15 until E21. In the cranial parts, all epithelial cells were positive, whereas in the caudal parts, CD15 was present only on their apical membranes. In the ovarian tube, uterine horn, and vagina, a moderate to high CD15 expression at birth gradually diminished to very low levels during postnatal days (P) 8 and 9. After P9, re-expression of CD15 occurred in the caudal part of the ovarian tube and in the uterus, increasing to a maximum at about P32. The findings provide (indirect) evidence for a correlation between the intensity of CD15 immunoreactivity and the serum concentrations of estrogens as well as of estrogen receptors in the urogenital tract. Since steroid hormone dependency can be regarded as a gauge of the differentiation of malignancies, it would be worthwhile correlating CD15 levels with those parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050146
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  • 5
    Electronic Resource
    Electronic Resource
    Localization of the CD15-epitope in the inner ear of the developing mouse (1996)
    Springer
    Cell & tissue research 283 (1996), S. 395-401 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Cochlear duct ; Vestibular organ ; Tectorial membrane ; Organ of Corti ; Endolymphatic sac ; 3-Fucosyl-N-acetyl-lactosamine (CD15) ; Glycoconjugates ; Mouse (MNRI)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The expression of the 3-fucosyl-N-acetyl-lac-tosamine (CD15) epitope during the embryonic development of the mouse inner ear has been immunohistochemically studied on paraffin sections from day 8.5 to day 19 of gestation. Consecutive steps of morphological development are accompanied by up- and down-regulation of CD15 expression and changing cell patterns. Expression levels are reduced once structural maturation has been accomplished. Since CD15 has been described as a determinant that is expressed during critical developmental steps, it is speculated that the changes in the epitope expression in the inner ear reflect relevant stages of differentiation. This system may thus serve as a model for understanding inner ear development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050550
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  • 6
    Electronic Resource
    Electronic Resource
    Developmental expression of the CD15 epitope in the hippocampus of the mouse (1997)
    Springer
    Cell & tissue research 289 (1997), S. 17-23 
    Details
    ISSN: 1432-0878
    Keywords: Key words: 3-Fucosyl-N-acetyl-lactosamine (FAL) ; Cell-to-cell interaction ; Dentate gyrus ; Hippocampal formation ; Mouse (NMRI)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The developmental expression of the 3-fucosyl-N-acetyl-lactosamine (CD15, Lex, SSEA-1) epitope has been examined immunohistochemically in paraffin sections of the mouse hippocampus. Labelling appeared initially at E10, with immunostaining of the ventricular surface of the hippocampal primordium and in the early hippocampal marginal zone. At E12 and E13, a group of cells in the marginal zone of the hippocampus was labelled. From E14 to E15, CD15 immunoreactivity delineated several boundaries in the developing hippocampal formation. A band of labelling was seen at these ages separating the fimbrioglial proliferative compartment from the primary dentate neuroepithelium. During late fetal and early postnatal life (E19–P5.5), two strong bands of labelling were visible in the stratum lacunosum moleculare and stratum oriens of CA3, and in the marginal zone and deeper layers of the subiculum. The bands in CA3 corresponded in position to the earliest afferents to the hippocampus from the entorhinal cortex. In later postnatal life (from P5.5), astrocytic CD15 labelling predominated in a mosaic camouflage pattern, as seen in the adult.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050848
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  • 7
    Electronic Resource
    Electronic Resource
    Time-dependent alterations of 3-fucosyl-N-acetyl-lactosamine (CD15) expression in the endolymphatic sac of adult guinea pigs after glycerol administration (1996)
    Springer
    European archives of oto-rhino-laryngology and head & neck 253 (1996), S. 136-141 
    Details
    ISSN: 1434-4726
    Keywords: Endolymphatic sac ; Glycoconjugates ; Fluid regulation ; Immune response ; Menière's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study examined the effect of glycerol administration on 3-fucosyl-N-acetyl-lactosamine (CD15) epitope expression in the endolymphatic sac (ES) of the guinea pig's inner ear. Adult guinea pigs were injected intravenously with glycerol (2 g/kg body wt.). CD15 expression was studied at 80 min up to 5 h after treatment. In untreated animals single cells and cell groups in the ES expressing CD15 epitope intra- and intercellularly were identified by immunohistochemistry to be mainly in the epithelial layer of the rugosal and distal part of the sac. Glycerol administration modulated the expression of CD15 epitope. In the epithelial layer, expression decreased and was nearly depleted after 3 h. After 4 h of glycerol administration, CD15 expression reappeared and reached the comparable level of controls. The numbers of CD15-positive cells in the lumen of the ES increased steadily and arrived at their the highest levels in 2-h specimens. The localization of CD15-epitope expression and its modulation after glycerol administration within the ES implies that this molecule may play a role in re-establishing the sac's normal function. In addition, we speculate that CD15 may be associated with processes of an immune response in the inner ear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00615110
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  • 8
    Electronic Resource
    Electronic Resource
    Special facets of diffusion and energy transfer in macromolecular systems (1998)
    Springer
    Czechoslovak journal of physics 48 (1998), S. 487-493 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We consider energy transfer in polymers in dilute solutions and model it as a purely incoherent, hopping exciton motion which ends at permanent traps, whose positions along the polymer chain are fixed. The transport involves not only steps along the chain but also steps between sites which are far away along the chain's backbone but near to each other in Euclidean space. This possibility leads to very peculiar features of the excitation's diffusion along the chain, due to strong correlations between subsequent steps. The process depends strongly on whether the chain is frozen or moves. We show that conformational changes influence trapping strongly, even if they are relatively slow on the time scale of the hopping motion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021206228357
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