Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 3442-3449 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A free-energy model is developed for polymer chains in good solvents. This model, which combines the ideas of polymer field theory with liquid-state theory, is valid in the dilute, semidilute, and concentrated regimes. The model is compared against computer simulation data for the equation of state of tangent hard-sphere chain fluids. At low concentrations, it accurately describes the thermodynamics of tangent hard-sphere chains, reproducing the universal scaling behavior of long chains. At high concentrations, the model has an accuracy comparable to those of previous equations of state for tangent hard-sphere chains.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 5580-5592 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Monte Carlo simulations for model polymer chains composed of hard spheres with square-well attractions were performed to find a precise relation between the parameters of a crossover theory and the parameters of the square-well chain. For sufficiently large bond lengths, there was a direct relation between the effective parameters of the crossover theory and the second- and third-virial coefficients of the square-well atoms. For the systems under study, the theta temperature is close to the Boyle temperature of the disconnected monomers, is mainly dependent on the details of the monomer–monomer interactions, and is only weakly dependent on the bond length of the chain. Above the theta temperature, the crossover theory is in good agreement with the simulation data. Near the theta point, the main effect of tricritical corrections is a shift in the critical amplitudes. Other effects are extremely small. The simulation data are consistent with the tricritical crossover theory. However, more precise data are needed to quantitatively test the tricritical crossover theory. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 2684-2691 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We develop a crossover theory for dilute polymer solutions, analogous to crossover theories for critical phenomena in simple fluids. In this theory, a critical degree of polymerization N* is found, which plays a similar role as the Ginzburg number in second-order phase transitions. To test the predictions of this theory, we perform Monte Carlo simulations of polymer chains composed of rigidly bonded hard spheres of various diameters and chain lengths. Various properties of these chains were analyzed, including the end-to-end distance distribution and mean-square radius of gyration. We find that the approach to the asymptotic scaling regime displays two types of crossover behavior, depending on the value of the model parameter u¯, which is a measure of the strength of the monomer–monomer excluded volume interaction: (i) u¯〈1 and (ii) u¯〉1. In case (i), the system exhibits crossover from a Gaussian chain to the Kuhnian chain, as the degree of polymerization increases. In case (ii), the system exhibits crossover from the rigid rod to a Kuhnian chain. Our crossover theory is found to work well for polymers with u¯〉1 only near the asymptotic scaling regime. However, for u¯〈1, the theory works well in all regimes. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 5026-5033 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We perform Monte Carlo calculations for the mean-square center-to-end distance, mean-square radius of gyration, and second virial coefficient of f=3 to 41 arm star polymers composed of rigidly bonded hard spheres of varying diameters. As with linear chains, there are two different crossover regimes: (i) crossover from the Gaussian chain to the Kuhnian chain limit, where the penetration function Ψ(f) increases monotonically with increasing polymer molecular weight, and (ii) crossover from the rigid-rod to the Kuhnian chain limit, where the penetration function decreases with increasing molecular weight. We propose a phenomenological approach for the extension of our previous crossover theory for linear polymers to star polymers. We show that the theoretical crossover function obtained earlier by Douglas and Freed [Macromolecules 16, 1854 (1984)] fails to reproduce the simulation data for the penetration function with f≥6, while the phenomenological crossover model is in good agreement with the simulation data up to f≤41. We also obtain a generalized crossover equation for the penetration function for linear and star polymers in good solvents. The crossover equation is able to accurately describe the variation of the infinite molecular weight limit of the penetration function Ψ*(f) with the number of arms f on the star polymer, and it predicts that Ψ*(f) approaches 2.39 in the limit f→∞. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Journal of fish diseases 25 (2002), S. 0 
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 437-438 (Oct. 2003), p. 269-272 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 48 (1992), S. 57-59 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-1106
    Keywords: Neural lobe allografts ; Hypothalamo-neurohypophysial tract ; Fine structure ; Neurophysin immunohistochemistry ; Neurosecretory axon regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neural lobe allografts placed stereotactically into the hypothalamo-neurohypophysial tract between the paraventricular and supraoptic nuclei were investigatd between 5 and 70 days post-transplantation (dpt). They contained temporally increasing numbers of neurophysin-positive axons. At the fine structural level, endogenous neurosecretory axons had virtually disappeared from successful (vascularized) grafts by 5 dpt. At this time, single host neurosecretory axons and especially numerous growth cones were associated with pituicyte processes and/or scalloped basal lamina scaffolds. Axon terminals containing neurosecretory granulated vesicles and microvesicles were present only occasionally at 5 dpt but became much more numerous subsequently. These terminals were associated with pituicytes and abutted the parenchymal basal lamina of pericapillary connective tissue spaces. In addition, beginning at 10 dpt, neurolemmocyte-like cells were associated with neurosecretory axons. At 70 dpt, the fine structural characteristics of grafted neural lobes were virtually indistinguishable from those of intact controls, except for the presence of occasional areas of more extensive connective tissue, nonfenestrated capillaries and neurolemmocyte-like cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Advances in contraception 4 (1988), S. 287-293 
    ISSN: 1573-7195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Resumé On a étudié par spectrophotométrie d'absorption atomique et histo-chimie la quantité et al localisation du cuivre libéré par un DIU au cuivre dans l'endomètre de lapines portant ce dispositif pendant 30 jours. Le cuivre libéré était principalement concentré dans le cytoplasme de l'épithélium cavitaire et glandulaire. Toutefois, si la continuité de l'épithélium n'était pas parfaite, par suite d'une atteinte par le dispositif, le cuivre pouvait être décelé dnas les cellules du stroma, qui semblaient être des leucocytes neutrophiles ou des lymphocytes. La concentration moyenne de cuivre dans le tissu utérin provenant de la corne portant le DIU au cuivre (82.24 μg/g poids sec) était significativement plus élevée que celle de l'élément controlatéral du dispositif (14.48 μg/g poids sec) et avait également tendance à être plus élevée que celle de la corne portant le dispositif en acier inoxydable (39.97 μg/g poids sec) et de sa corne controlatérale (18.03 μg/g poids sec).
    Abstract: Resumen Espectofotometría de absorción atómica e histoquímica fueron utilizadas para estudiar el contenido y la localización del cobre liberado por un DIU con cobre en el endometrio de conejas con el dispositivo durante 30 días. El cobre liberado se acumuló principalmente en el lumen y en el citoplasma del epitelio glandular. Sin embargo, si la integridad del epitelio estaba imperfecta debido a la presencia del dispositivo, el cobre podía ser detectado en células des estroma que parecían ser leucocitos neutrófilos o linfocitos. La concentración media de cobre en el tejido del cuerno uterino con el DIU con cobre (82.24 μg/g peso seco) fué significativamente mas alta que la del opuesto (14.48 μg/g peso seco) y también tendía a ser mas alta que la del cuerno con el dispositivo de acero inoxidable (32.97 μg/g peso seco) y su cuerno opuesto (18.03 μg/g peso seco).
    Notes: Abstract Atomic absorption spectrophotometry and histochemistry have been employed to study the content and localization of copper released from a CuIUD in the endometrium of rabbits bearing the copper device for 30 days. The released copper was mainly accumulated in the luminal and glandular epithelial cytoplasm. However, if the succession of the epithelia was imperfect due to the impairment by the device, copper could be detected in the stroma cells, which appeared to be neutrophilic leukocytes or lymphocytes. The mean concentration of copper in the uterine tissue of the CuIUD-bearing horn (82.24 μg/g dry weight) was significantly higher than that of the contralateral one (14.48 μg/g dry weight), and also tended to be higher than that of the horn bearing the stainless steel device (32.97 μg/g dry weight) and its contralateral horn (18.03 μg/g dry weight).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...