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  • 1
    Electronic Resource
    Electronic Resource
    A quantitative analysis of the thermoelectric power measurements on composite Al-Ge films (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 7441-7445 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thermoelectric power (Seebeck coefficient) measurements at room temperature have been made on composite Al-Ge films for aluminum volume fractions ranging from 20% to 100%, the metal-insulator transition being at about 55%. These measurements were motivated to test theoretical predictions recently suggested by Bergman and Levy. The electrical conductivity, substituted in their equation, was obtained both by direct measurements and an effective media equation while the thermal conductivity was obtained from two different effective media equations. The agreement between the theoretical and experimental results support the correctness both of their theory and the effective media equations used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353987
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  • 2
    Electronic Resource
    Electronic Resource
    A grain consolidation model for the critical or percolation volume fraction in conductor-insulator mixtures (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 3681-3682 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The critical volume fraction, at which the conducting component in conductor-insulator mixtures first becomes continuous or percolates, plays a very important role in both percolation theory and the generalized effective-media equation. The growth mechanism, by which very low (≤0.05) critical volume fractions for nearly spherical conducting powders in insulating hosts, such as polymers, are obtained, is not well understood. In this paper a simple model, based on the computer-generated model of Roberts and Schwartz [Phys. Rev. B 31, 5990 (1985)] for grain consolidation in porous media, for the very low critical volume fractions observed in some conductor-insulator mixtures is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349216
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  • 3
    Electronic Resource
    Electronic Resource
    A quantitative analysis of the volume fraction dependence of the resistivity of cermets using a general effective media equation (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 195-199 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The results analyzed, all from previous work, are for W-Al2O3 (as prepared and annealed; 300 K) and Ni-SiO2 (4.2 and 291 K). These results, in which the resistivity changes from 10−5 to 107 Ω cm as the metal volume fraction is varied, can all be quantitatively fitted to a general effective media (GEM) equation. The GEM equation was developed as an interpolation between Bruggeman's symmetric and asymmetric media equations for ellipsoidal grains. It has four parameters. The conductivities of the low [σ(lo)] and high [σ(hi)] conductivity components, fc=(1−cursive-phic), where cursive-phic is the critical (percolation) volume fraction of the σ(hi) component and t is an exponent. f is the volume fraction of the dielectric or σ(lo) component. As, when σ(lo)=0 or σ(hi)=∞ the GEM equation reduces to the percolation equations, it can also be regarded an interpolation formula between these equations. The W-Al2O3 (as prepared; 300 K) and Ni-SiO2 (291 K) results need a five-parameter fit as ρ(hi) [1/σ(lo)] is modeled as an intergranular tunneling process with ρ(hi)=ρ(0)exp{C[(1−fc)/(1−f )]1/3−1}, ρ(0) and C being variable parameters. The log rms deviations for fits are W-Al2O3 (as prepared) 3.3%, W-Al2O3 (annealed) 0.66%, Ni-SiO (4.2 K) 2.3%, and Ni-SiO2 (291 K) 1.3%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347114
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  • 4
    Electronic Resource
    Electronic Resource
    Alzheimer Aβ Amyloid Forms an Inhibitory Neuronal Substrate (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Alzheimer's disease (AD) is identified by the accumulation of amyloid plaques, neurofibrillary degeneration, and the accompanying neuronal loss. AD amyloid assembles into compact fibrous deposits from the amyloid β(Aβ) protein, which is a proteo-lytic fragment of the membrane-associated amyloid precursor protein. To examine the effects of amyloid on neuron growth, a hybrid mouse motoneuron cell line (NSC34) exhibiting spontaneous process formation was exposed to artificial “plaques” created from aggregated synthetic Aβ peptides. These correspond to full-length Aβ residues 1–40 (Aβ1–40), an internal β-sheet region comprising residues 11–28 (Aβ11–28), and a proposed toxic fragment comprising residues 25–35 (Aβ25–35). Fibers were immobilized onto culture dishes, and addition of cells to these in vitro plaques revealed that Aβ was not a permissive substrate for cell adhesion. Neurites in close contact with these deposits displayed abnormal swelling and a tendency to avoid contact with the Aβ fibers. In contrast, Aβ did not affect the adhesion or growth of rat astrocytes, implicating a specific Aβ-neuron relationship. The inhibitory effects were also unique to Aβ as no response was observed to deposits of pancreatic islet amyloid poly-peptide fibers. Considering the importance of cell adhesion in neurite elongation and axonal guidance, the antiadhesive properties of Aβ amyloid plaques found in vivo may contribute to the neuronal loss responsible for the clinical manifestations of AD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.62031227.x
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of Messenger RNA from the Cerebral Cortex of Control and Alzheimer-Afflicted Brain (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 47 (1986), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: A detailed comparative study of RNA transcripts isolated from the neocortex of control and Alzheimer postmortem brains was made to determine whether morphological changes in the chromatin of Alzheimer neurons and glia, which we reported earlier, are accompanied by changes in the products of transcription. A number of parameters were determined including the yields of total and mRNA per gram of tissue, the relative proportions of polyadenylated [poly(A) +] mRNA in the total RNA, the size distribution of the transcripts and the length of their poly(A) tails, and the nature of their in vitro translation products. The levels of endogenous RNase activity were also measured. The effect of the agonal process on the transcript complement was examined by Northern blotting of a cloned human heat-shock cDNA to total human brain RNA. Our results reveal that the yields of total RNA, unadenylated mRNA, and poly(A) tail lengths from Alzheimer neocortex samples do not differ significantly from those of control and non Alzheimer dementia neocortex. On the other hand we find a significant reduction in the levels and proportion of poly(A)+ mRNA in the Alzheimer samples as compared to control brain samples. Quantitative rather than qualitative differences were observed in the in vitro translation products when programmed with control and Alzheimer mRNA. No differences were found in the levels of RNase activity between control and Alzheimer simples. Heatshock mRNA transcripts were detected in brain samples from patients in whom fever was associated with death. The direct correlation of reduced poly(A)+ mRNA and chromatin condensation in Alzheimer neocortex suggests a cause-and-effect relationship. Whether all transcribed genes are affected or only a specific subset has yet to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1986.tb00708.x
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in Chromatin Structure Associated with Alzheimer's Disease (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 37 (1981), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The enzyme micrococcal nuclease was used to examine the accessibility of chromatin extracted from brains of 13 patients with senile and presenile dementia of the Alzheimer type. Compared with chromatin extracted from brains of 8 patients without neurological signs or brain pathology and brains of 7 patients with nonAlzheimer dementia, Alzheimer chromatin was less accessible to this enzyme-. Reduced accessibility was reflected by a reduced yield of mononucleosomes in comparison with dinucleosomes and larger oligomers. Both neuronal and glial chromatin were found to be similarly affected. The reduced yield of mononucleosomes from Alzheimer chromatin is not due to their increased breakdown, but is probably related to protein associated with the internucleosomal linker region that retards nuclease action. Dinucleosomes isolated from control and Alzheimer nuclease digests were examined for their protein complement. Three perchloric acid-soluble proteins situated in the histone HI region of sodium dodecyl sulfate (SDS) gels were present in elevated levels in Alzheimer dinucleosomes. These results represent the first example of altered chromosomal proteins associated with a diseased state of the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1981.tb04670.x
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of Sesquiterpene Lactones on Development of Aedes atropalpus and Relation to Partition Coefficient (1985)
    s.l. : American Chemical Society
    Journal of natural products 48 (1985), S. 581-584 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50040a010
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  • 8
    Electronic Resource
    Electronic Resource
    INDEX NUMBERS OF LINER FREIGHT RATES IN UNITED KINGDOM TRADES 1946–1957 (1958)
    Oxford, UK : Blackwell Publishing Ltd
    Bulletin of economic research 10 (1958), S. 0 
    Details
    ISSN: 1467-8586
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1467-8586.1958.tb00351.x
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  • 9
    Electronic Resource
    Electronic Resource
    Bragg's influence on progress in optical computations (1970)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 26 (1970), S. 189-193 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: An attempt is made in this paper to indicate the impact that one small part of Sir Lawrence Bragg's gross contributions have had upon crystallography during his lifetime up to the age of eighty. The small part referred to is the growing field of optical computation. Since this paper is partly for the enlightenment of the reader as well as a salute to history, descriptions of five basic optical operations are given: I, addition; II, multiplication; III, reciprocation; IV, convolution and V, diffraction. The role of Bragg and his co-workers is woven into each description. Finally as an extrapolation, a further process is described: VI, inverse imaging.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739470000530
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  • 10
    Electronic Resource
    Electronic Resource
    The crystallography of two compounds containing the oxides of copper and molybdenum (1956)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 9 (1956), S. 316-317 
    Details
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0365110X56000875
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