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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 69 (1997), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: We have shown previously that serum inhibits tight junction formation in a retinal epithelial cell culture model for the blood-brain barrier. We have now examined in detail the effects of serum on the tight junctions. Our data show that serum induces a breakdown in tight junction function as indicated by decreased transepithelial electrical resistance and increased permeability. Rat serum had effects similar to those of bovine serum, indicating that the activity is species-independent. The effect is concentration-dependent, reversible, and specific for the apical surface, suggesting the involvement of a specific receptor-ligand interaction. Differences in the time course, response magnitude, and structural manifestations between the serum-induced breakdown and that induced by switching the cultures to a low-calcium medium suggest fundamental differences in their mechanisms. The calcium switch results in an immediate and complete junctional breakdown with cell retraction and perinuclear translocation of both actin and the tight junction protein zonula occludens-1. The serum-induced breakdown occurs slowly, is incomplete, and is manifested structurally by decreases in zonula occludens-1 protein, whereas actin organization is unchanged. Thus, serum induces a specific breakdown in retinal epithelial cell tight junctions that may be mediated by effects on the expression of zonula occludens-1.
    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 78 (1995), S. 2489-2497 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We study the effects of the spin-orbit (SO) split-off band coupling with the heavy- and the light-hole bands on the band structure, density of states, dipole moment, and the linear and nonlinear optical gains of strained-layer quantum wells by comparing the 6×6 and the 4×4 Luttinger–Kohn models. First, a unitary transformation is found that block diagonalizes the 6×6 Hamiltonian into two 3×3 blocks that are real symmetric in the finite difference formulation. We find that the peak gains are overestimated, especially in the case of a tensile quantum well, in the 4×4 model, for the InGaAs–InP quantum-well systems which show weak SO coupling. The change of the density of states is suggested to be the dominant factor for the discrepancy of the results between the 6×6 and the 4×4 models in the linear gain. For nonlinear gain the discrepancy between the two models is smaller than that of the linear gain because the change of the fourth-order dipole moment in the nonlinear gain compensates that of the density of states. We also considered InGaP–In(AlGa)P quantum wells which have very narrow SO split-off energy. In this case, because of the strong coupling between the SO bands and the hole bands, the InGaP–In(AlGa)P quantum-well systems show more complicated behavior. The peak gain of strained quantum well is overestimated in the low carrier injection region and is underestimated in the high injection, in the 4×4 model. On the other hand, the peak gain of an unstrained quantum well is overestimated in the 4×4 model over the wide range of carrier densities. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 2572-2576 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Utilizing the propagation delay in a chain of logic elements to digitize short time intervals has a high potential in various applications because the method has an ultrashort measurement "dead time" and its complete timing circuit can be easily integrated in a single semiconductor chip. However, the existing single-lined chain suffers from serious nonlinearity due to the longer path lengths at the foldings which are unavoidable when the number of delay elements is large as high time resolution requires. We propose a new configuration in which the delay chain is branched. The delay elements of each branch evenly subdivide the corresponding larger folding path so all units have the same delay time. The proposed time-to-digital converter with an 81-delay-unit branched chain and a built-in calibration circuit has been implemented on a commercial programmable logic device. It is used to interpolate different time durations within the 100 ns period of a standard 10 MHz clock. The digital time deviates less than 0.3 ns throughout the entire range. A similar single-lined delay chain, constructed for comparison, exhibits timing error up to 32.7 ns. A major improvement in linearity has been achieved by our device. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 795-797 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Strain and quantum size effects on the optical matrix elements for both TE and TM polarizations of strained quantum wells are studied theoretically including the spin-orbit coupling. A set of universal curves for the polarization dependent optical matrix elements as a function of strain is shown. These curves will be very helpful for a quick estimate of the optical matrix elements including the effects of the spin–orbit splitoff band for modeling the optical gain and absorption using strained quantum wells. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 33 (1994), S. 860-870 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 58 (1993), S. 1754-1761 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 26 (1993), S. 2234-2239 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 23 (1990), S. 1484-1486 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It has been assumed that there is a relationship between periodontal diseases and diabetes mellitus, however the putative periodontal microorganisms in non-diabetes mellitus (non-DM) individuals and non-insulin-dependent diabetes mellitus (NIDDM) patients have not been well studied. In this study, the detection rates of 5 putative periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Eikenella corrodens, Treponema denticola, and Candida albicans by polymerase chain reaction (PCR) between NIDDM and non-DM adults were compared. A total of 246 adults were randomly recruited and periodontal parameters including: plaque index (PlI), gingival index (GI), probing depth (PD) and attachment level (AL) were recorded. Subgingival plaque samples were collected by sterile curettes from the most diseased and healthy sites based on PD and AL. The differences in periodontal parameters and microbiological data in healthy and diseased sites between non-DM and NIDDM patients were compared by chi-square analysis. The results showed no significant differences in age, gender, GI, PlI, PD, and prevalence of the 5 microorganisms between the NIDDM and the non-diabetic groups. However, except for A. actinomycetemcomitans, the prevalence of the periodontal microorganisms tested was significantly higher (p〈0.01) in diseased sites than in the healthy sites in both groups. The PlI, GI, PD and AL were significantly higher in T. denticola positive sites than in negative sites. The results suggested that P. gingivalis, T. denticola, E. corrodens and C. albicans may play important roles in the periodontitis of both NIDDM and non-DM individuals, however the etiology of periodontitis in both groups may not be different from each other.
    Type of Medium: Electronic Resource
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