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  • 11
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 8453-8462 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Classical molecular dynamics calculations are performed between 25 and 55 K to investigate the structure and the dynamics of the CO monolayer adsorbed on NaCl(100) surface. The simulation is based on the most recent potential available for this system and the results are compared with experimental data issued from polarization infrared spectroscopy and helium atom scattering. We show that the monolayer adopts a (2×1) structure at 25 K, with two molecules per unit cell. The corresponding angular motions perpendicular and parallel to the surface are clearly librational. As temperature rises, the molecular axes remain tilted with a librational motion perpendicular to the surface, while the translational and orientational motions parallel to the surface behave much more freely, leading to an orientationally disordered structure at 55 K. These features suggest that dynamical effects in the (2×1) layer are responsible for an ordered/disordered transition observed as temperature increases, instead of the phase transition from ordered (2×1) to (1×1) structures which was previously inferred. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 6963-6976 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We determine the profile of the vibrational band of an ordered monolayer adsorbed on a clean surface corresponding to the infrared spectrum and to the resonant infrared-visible sum frequency generation spectrum. The theoretical model is based on the renormalization of the monolayer and substrate Hamiltonians. The harmonic dynamics of the effective vibrons characterizing the collective internal vibrations of the admolecules is written in terms of a complex dynamical matrix whose elements can be expressed as correlation functions of the external libron and phonon modes. The dephasing broadening is obtained by solving a master equation for the time evolution of the vibron modes while the external dynamics of the layer is described by using molecular dynamics simulation. An application to the calculation of the profile of the vibrational band of the low temperature (2×1) CO monolayer adsorbed on NaCl(100) is performed without any adjustable parameter by considering a well established semiempirical potential to describe the molecule-surface and molecule-molecule interactions. The comparison with experimental spectra shows that the homogeneous phase relaxation due to the coupling between the vibrons and the monolayer phonons-librons accounts for the most part of the peak width and interprets the temperature dependence of this width. Extension of the calculations to the interpretation of the orientationally disordered phase obtained for CO at higher temperature is done which corroborates very well the temperature behavior of the monolayer structure and profile. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 13
    facet.materialart.
    Unknown
    Leiden : Periodicals Archive Online (PAO)
    T'oung pao. ser.2:1 (1900) 397 
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    International journal of colorectal disease 7 (1992), S. 38-42 
    ISSN: 1432-1262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Entre 1977 et 1989 151 malades ont été traités dans notre institution pour une diverticulite aigue du sigmoide. 31 malades ont été opérés pour une péritonite diffuse et ont été exclus de cette étude. 120 malades avaient une maladie localisée. Il y a avait 59 hommes et 61 femmes d'un âge moyen de 60 ans (30–87 ans). 13 étaient âgés de 40 ans ou moins. “Une diverticulite phlegmoneuse” (sans abcès péricolique) fut diagnostiquée dans 78 cas (groupe I). Un abcès péricolique a été identifié dans 42 cas (groupe II). Le traitement médical fut couronné de succès chez 97 % des patients du groupe I.15 patients seulement ont nécessité une résection élective retardée pour récidive ou complication chronique dans les 24 mois suivants. Il n'y a pas eu décès opératoire. Tous les autres patients allaient bien après une surveillance moyenne de 5 ans (9–144 mois) sans aucune cause de mort en relation avec la maladie. Les patients présentant un abcès péricolique localisé (groupe II,n=42) furent initialement traités soit conservativement (n=22), soit par un drainage plus ou moins extensif (n=20). Il y eut 2 morts dans le groupe “conservatif”. Une résection colique d'emblée ou retardée fut indiquée dans 34 cas en raison d'une suppuration incontrôlée, d'une récidive ou de complications chroniques secondaires. On conclut qu'une classification appropriée de la maladie est essentielle. Si il n'y a pas de péritonite, la présence d'un abcès est le principal facteur à la fois de pronostic et de traitement. La plupart des patients qui developpent une diverticulite phegmoneuse aigue vont bien avec un traitement conservateur et la résection prophylactique n'est pas indiquée. La colectomie curative est réservée aux patients qui développent des complications chroniques dans les quelques mois suivants. D'autre part, un pourcentage de récidives et de complications élevé fut observé chez les patients qui avaient un abcès péricolique. Le drainage de l'abcès, eventuellement suivi d'une colectomie élective secondaire, pourrait être le traitement approprié.
    Notes: Abstract Between 1977 and 1989, 151 patients were treated in our institution for acute sigmoid diverticulitis. Thirty-one patients were operated on for diffuse peritonitis, and were excluded from the study. One hundred twenty patients had localized disease. There were 59 men and 61 women, with a mean age of 60 years (range, 30 to 87 years). Thirteen were under 40 years of age. A “phlegmonous” diverticulitis (no pericolic abscess) was diagnosed in 78 cases (group I). A pericolic abscess was identified in 42 cases (group II). The medical treatment was successful in 97% of the patients of the group I. Only 15 patients required a delayed elective resection for recurrence or chronic complications, within the next 24 months. There were no operative deaths. All the other patients were doing well after a mean follow-up of 5 years (9–144 months), without any disease-related death. Patients presenting with a localized pericolic abscess (group II,n=42) were initially treated either conservatively (n=22) or by a more or less extensive drainage (n=20). There were two deaths in the “conservative” group. Primary or delayed colonic resection was indicated in 34 cases because of uncontrolled sepsis, recurrence or secondary chronic complications. It is concluded that accurate classification of the disease is essential. If no peritonitis has developed, the presence of an abscess is the main determinant in both prognosis and treatment. Most patients who develop an acute phlegmonous diverticulitis do well with conservative treatment, and prophylactic resection is not indicated. Curative colectomy is reserved for patients developing persistent complications over the next few months. On the other hand, high rates of recurrence and complication are observed among the patients with a pericolic abscess. Drainage of the abscess, possibly followed by a secondary elective colectomy, could be the appropriate treatment.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 40 (1995), S. 308-314 
    ISSN: 1573-2568
    Keywords: eosinophilic gastroenteritis ; colitis ; cholangitis ; steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eosinophilic gastroenteritis (EG) is a rare condition that most commonly affects the stomach and intestine. Large bowel involvement has also been described. We report a case of EG presenting with colitis and cholangitis. This is the first case of associated cholangitis demonstrated radiologically and histologically. Simultaneous biliary and gastrointestinal tract involvement suggest a common link between EG and hypereosinophilic syndrome (HES). However, HES requires high peripheral hypereosinophilia and several organs including gastrointestinal tract, lung, heart, infiltrated with eosinophils. The patient's condition improved with corticosteroids.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1573-2568
    Keywords: mucosal lymphocytes ; flow cytometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A method was developed to isolate colonic intraepithelial lymphocytes in patients with ulcerative colitis (N=8) and normal controls (N=13) in order to characterize their phenotype using a panel of monoclonal antibodies and flow cytometry. In both groups, the majority of the cells are of the CD3+CD8+ phenotype associated with cytotoxic/suppressor function. The CD4/CD8 ratios were similar. Virtually no B cells or macrophages were found. An increase in cells coexpressing the CD3 and HLA-DR molecules and a decrease in natural killer cells (CD3, CD16+CD56+) were found in ulcerative colitis, but this was not significant. There were no differences in the proportions of CD8+ and CD4+ cells expressing the Leu8 antigen between ulcerative colitis and controls. Thus a population of colonic intraepithelial lymphocytes has been isolated and, although they may be functionally different in ulcerative colitis compared with controls, this cannot be explained in terms of phenotypic characteristics.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    International ophthalmology 14 (1990), S. 37-41 
    ISSN: 1573-2630
    Keywords: cotton-wool spots ; AIDS related complex (ARC) ; HIV
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Twenty-nine patients with the AIDS Related Complex (ARC) were studied retrospectively. Cotton-wool spots (CWSs) were the main ophthalmological finding, present in 9 patients (31%) at this stage of the disease. The CWSs were asymptomatic and were therefore discovered during a routine examination. The proportion of patients with significant weight loss was greater among ARC patients with CWSs than among those with normal fundi. Leukocyte counts were found to be significantly lower (p = 0.03, odds ratio 10.0 [1.24 to 80.4])among ARC patients with CWSs. Lymphocyte counts and the CD4/CD8 ratio were also found to be diminished in these patients. Among the nine patients with CWSs during ARC, seven developped major opportunistic infections or HIV (Human Immunodefiency Virus) related neoplasias during the following months (3.8 ± 3.5 months). These findings are consistent with a poorer prognosis for HIV infected patients who have CWSs.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 203-211 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the electrochemical reduction of an electroactive polymer several thousand electrons may be transferred to a single molecule. For polymers with noninteracting centers, recently developed theory indicates that the current - potential response would be identical with that of the corresponding molecule solvation, structural change, and variation in ionic environment, and may be used to probe these factors. A series of model compound of poly(vinylbenzophenone) and of poly(vinylbenzophenone-co-styrene) were prepared and investigated. In this study samples of various constant chain length with differing spacing of electroactive centers were employed. The current - potential measurements corresponded to the ideal theoretical case. This indicates that the behavior of the electroactive groups attached to the polymer chain was not influenced by the macromolecular environment or by neighboring group interaction.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 109-118 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reduction of an electroactive polymer at an electrode involves the transfer of a large number of electrons to a single molecule. A quantitative study of this process indicates whether the system behaves ideally. The electron transfer process in polyvinylbenzophenone and in polyvinylbenzophenone-co-styrene in N,N-dimethylformamide solution was investigated by voltammetry at a rotating disk electrode. It is concluded that benzophenone (BP) groups attached to the polymer backbone are noninteracting electroactive centers and that every BP group is reducible at the electrode. The relationship between limiting current and molecular weight was examined quantitatively for a series of polymers of low dispersity with molecular weights ranging up to 300,000, and with a controlled, varied content of electroactive groups. The diffusion coefficient was determined as a function of molecular weight from the electrochemical data, and was found to be in good agreement with the theoretical model based on transport properties. The dependence of the diffusion coefficient on concentration of polymer and on temperature were investigated and activation energies determined.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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