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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 5424-5426 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The isostructural uranium monopnictides and monochalcogenides have become prototype systems in actinide research with respect to their unusual magnetic properties. We have investigated the origins in the electronic structure of the variation in magnetic behavior as the degree of 5f-electron localization changes from localized to itinerant on going up the pnictogen or chalcogen column, thus decreasing the U-U separation. We have applied a synthesis of: (1) A phenomenological theory of orbitally driven magnetic ordering which includes both the hybridization-induced and the RKKY exchange interactions on an equal footing, and (2) Ab initio electronic structure calculations, based on the linear-muffin-tin-orbital method, allowing a first-principles evaluation of the parameters entering the model Hamiltonian. We have investigated systematically characteristic trends and changes of the 5f-state resonance width, the hybridization potential, and the hybridization-induced and RKKY exchange interactions with chemical environment, on going down the pnictogen or chalcogen column and on going from the weakly hybridizing pnictides to the more strongly hybridizing chalcogenides.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 1211-1218 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In contact with an environment, a solid may gain or lose mass due to, for example, deposition or etching. As the reaction proceeds, the surface of the solid moves, either extending or receding. If the solid is under stress, the elastic energy adds to the driving force of the reaction, and may cause the surface to roughen. This phenomenon has recently led to a novel experimental technique to determine the stress state in a solid by using an atomic force microscope to scan the surface profiles before and after etching. Stress is also known to change the mobility of a reaction. By this mechanism, the stress may either roughen or stabilize a flat surface. This article describes a linear perturbation analysis of a three-dimensional solid surface evolving under stress, using a general kinetic law. It is found that when the reaction is near equilibrium, the stress effect on driving force dominates; when the reaction is far from equilibrium, the stress effect on mobility dominates. Under these two conditions, the surface profile spectra have different patterns and length scales. The implications for the stress measurement technique are discussed. It is suggested that the same experimental procedure be used to measure surface energy and activation strains. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 5326-5335 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Equations of state for hard sphere chain molecules are derived within the framework of second order perturbation theory of polymerization (TPT2). The present formulation differs from the original Wertheim's treatment by dealing with molecules with a fixed number of beads. However, the two versions yield very close numerical results for chains composed of freely jointed spheres, showing the insensitivity of the pressure of these fluids to polydispersity. The case of star-like molecules and chain mixtures is also considered. Theoretical predictions are compared to available simulation data, using recent results for the triplet correlation function for hard spheres in rolling contact. Some predictions for the pressure of freely rotating chains and that of trimers as a function of the bond angle are given.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 266-270 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a technique for measuring the water vapor supersaturation of normal air over a temperature range of −40(approximately-less-than)T(approximately-less-than)0 °C. The measurements use an inexpensive commercial hygrometer which is based on a thin-film capacitive sensor. The time required for the sensor to reach equilibrium was found to increase exponentially with decreasing sensor temperature, exceeding 2 min for T=−30 °C; however, the water vapor sensitivity of the device remained high down to this temperature. After calibrating our measurement procedure, we found residual scatter in the data corresponding to an uncertainty in the absolute water vapor pressure of about ±15%. This scatter was due mainly to long-term drift, which appeared to be intrinsic to the capacitive thin-film sensor. The origin of this drift is not clear, but it effectively limits the applicability of this instrument for absolute measurements. We also found, however, that the high sensitivity of the thin-film sensor makes it rather well suited for differential measurements. By comparing supersaturated and saturated air at the same temperature we obtained a relative measurement uncertainty of about ±1.5%, an order of magnitude better than the absolute measurements. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 3705-3706 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We propose simple configurations to measure the thermoelectric power and the four-probe resistivity simultaneously for different types of samples.© 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Publishing Ltd/Inc.
    Wound repair and regeneration 13 (2005), S. 0 
    ISSN: 1524-475X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The MRL mouse is the only known strain of mouse that can regenerate cardiac lesions and completely heal ear punches without scarring. To determine if the MRL also has greater regeneration capabilities in amputated digit tips, right paw digit tips of neonatal mice were dissected, with the left front paws as uncut controls. Controls used for regeneration comparison were the DBA, B6, C3H, and 129 inbred mouse strains. Consecutive X-ray images were captured of the left and right paws at 0, 7, 14, 21, and 28 days postamputation. MRL mouse digit tips regenerated greater in comparison to all strains tested (p 〈 0.05). We next undertook whole genome microarray analysis to identify the genetic mechanisms that contribute to differences in digit tip regeneration. Over 400 genes out of 15,000 were significantly differentially expressed (p 〈 0.05) in MRL and DBA mice at day 4 in comparison to day 0 control tissue. Of these, 170 genes were upregulated and 280 were downregulated in both mouse strains. Pathway analysis reveals that genes in the BMP/TGF pathway are differentially expressed in both mouse strains (p 〈 0.05). Multiple differences between MRL and DBA strains were found in transcription factors that are implicated in gastrulation, including FMN2 and SHRM. Additional differentially expressed genes include NET1 in the WNT signaling pathway. Immunohistochemistry indicates that these proteins are highly expressed in the nuclei of chondrocytes in regenerating digits. We conclude that MRL mice show greater regenerative capacity to heal digit tips and that the increased regenerative capacity of MRL mice may be due to strain specific increased expression of genes involved in the WNT pathway and genes involved in embryonic pattern formation.Acknowledgments:  This work was supported by Assistance Award DAMD17–03–2–0021 and is administered by the US Army Medical Research Activity, 820 Chandler St., Ft. Detrick, MD.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 57 (1991), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: : The weaver mutant mouse has a genetically determined defect in the nigrostriatal dopaminergic system. The present study was undertaken to test the hypothesis that in the weaver mutant mouse, striatal nerve terminals undergo compensatory changes in response to this deficiency. To test this hypothesis, we studied the basal and stimulated release of dopamine from striatal slices of weaver mutant mice and matched controls. By using a superfusion system and concentrating the superfusate by passage over alumina, resting dopamine release could be determined in the weaver mutant despite the fact that striatal tissue content of dopamine in these mice is reduced by 〉75% compared with control mice. Fractional resting release of dopamine in weaver striatal slices was significantly elevated compared with that in controls, suggesting that the release mechanisms in the weaver may be adapting to overcome the dopamine deficit. Potassium-evoked release (24 and 48 mM potassium) was not significantly different between the two genotypes. In contrast, amphetamine-evoked release (1 μM) was significantly greater in the weaver mice than in controls. In both genotypes, release evoked by amphetamine was completely inhibited by cocaine, implicating the dopamine uptake carrier in this release process. These findings suggest that fundamental differences in dopamine release mechanisms exist between weaver and control mice and support the hypothesis that compensatory mechanisms may develop in neurons in response to dopamine deficits.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 64 (1995), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The weaver mutant mouse (wv/wv) has an ∼70% loss of nigrostriatal dopamine (DA) neurons, but the fractional DA release evoked by amphetamine (but not a high potassium level) has been shown to be greater from striatal slices of the weaver compared with +/+ mice. In the present work we tested the hypothesis that fractional DA release from weaver striatum would be greater when release was mediated by the DA transporter. Serotonin (5-HT)-stimulated fractional DA release was greater from weaver than from +/+ striatum. The release evoked by 5-HT in the presence of 10 µM nomifensine (an antagonist of the DA transporter) was less than in its absence, but the difference between weaver and +/+ striatum remained. In the presence of nomifensine, 1-(m-chlorophenyl)biguanide, classified as a 5-HT3 agonist, also induced a greater fractional release from weaver compared with +/+ striatum. When veratridine was used at a low concentration (1 µM), the fractional evoked release of DA was higher from the weaver in the presence and absence of nomifensine. These findings suggest that the reason for the difference in the responsiveness of the two genotypes to these release-inducing agents is not related to DA transporter function.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Journal of neurochemistry 72 (1999), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Carboxyfullerene, a water-soluble carboxylic acid derivative of a fullerene, was investigated as a protective agent against iron-induced oxidative stress in the nigrostriatal dopaminergic system of anesthetized rats. Intranigral infusion of exclusive carboxyfullerene did not increase lipid peroxidation in substantia nigra or deplete dopamine content in striatum. Infusion of ferrous citrate (iron II) induced degeneration of the nigrostriatal dopaminergic system. An increase in lipid peroxidation in substantia nigra as well as decreases in K+-evoked dopamine overflow and dopamine content in striatum were observed 7 days after the infusion. Co-infusion of carboxyfullerene prevented iron-induced oxidative injury. Furthermore, tyrosine hydroxylase-immunoreactive staining showed that carboxyfullerene inhibited the iron-induced loss of the dopaminergic nerve terminals in striatum. The antioxidative action of carboxyfullerene was verified by in vitro studies. Incubation of brain homogenates increased the formation of the Schiff base fluorescent products of malonaldehyde, an indicator of lipid peroxidation. Both autooxidation (without exogenous iron) and iron-induced elevation of lipid peroxidation of brain homogenates were suppressed by carboxyfullerene in a dose-dependent manner. Our results suggest that intranigral infusion of carboxyfullerene appears to be nontoxic to the nigrostriatal dopaminergic system. Furthermore, the potent antioxidative action of carboxyfullerene protects the nigrostriatal dopaminergic system from iron-induced oxidative injury.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical and experimental dermatology 29 (2004), S. 0 
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Epidermolysis bullosa (EB) pruriginosa is a subtype of dominant dystrophic EB (DDEB), characterized by severe pruritus and blistering localized to the extensor surface of the extremities. EB pruriginosa exhibits extensive clinical heterogeneity with variable expression and delayed age of onset. Mutations in the COL7A1 gene, especially in glycine residues within Gly-X-Y repeats, have been shown to cause this form of DDEB. Here, we report a novel COL7A1 mutation in a Taiwanese pedigree with EB pruriginosa. Using PCR and direct sequence analysis we have identified a G→T transversion at nucleotide 7097 in exon 92 of COL7A1, converting a glycine residue to valine (G2366V). The mutation resides within a consecutive, uninterrupted stretch of 17 Gly-X-Y residues in the triple-helical domain of type VII collagen. Interestingly, an affected member of this family also displayed elevated IgE levels, previously reported in some patients with this disorder. Our finding further implicates COL7A1 mutation in the pathogenesis of EB pruriginosa and underscores the heterogeneous clinical symptoms of glycine mutations in DDEB.
    Type of Medium: Electronic Resource
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