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  • 1
    Electronic Resource
    Electronic Resource
    Expression of the tumor necrosis factor α gene and early response genes by nodularin, a liver tumor promoter, in primary cultured rat hepatocytes (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 413-419 
    Details
    ISSN: 1432-1335
    Keywords: Key words Tumor necrosis factor α ; Early-response genes ; Liver carcinogen ; mRNA stabilization ; Protein phosphatase inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nodularin is a new liver carcinogen possessing a potent tumor-promoting activity in rat liver, mediated through inhibition of protein phosphatases 1 and 2A, and a weak initiating activity. Since we previously reported evidence that nodularin up-regulated expression of the tumor necrosis factor α gene (TNFα) and early-response genes in rat liver after its i.p. administration, and since TNFα had tumor-promoting activity in vitro, it is possible that TNFα itself is involved in liver tumor promotion. We investigated whether hepatocytes themselves induce expression of the TNFα gene and early-response genes in primary cultured rat hepatocytes treated with nodularin. Like nodularin, microcystin-LR, which is another liver tumor promoter belonging to the okadaic acid class, strongly induced TNFα gene expression in rat hepatocytes, as well as TNFα release from those cells into the medium. On the other hand, 12-O-tetradecanoylphorbol-13-acetate, which has been reported to induce no tumor promotion in rat liver, induced no apparent expression of the TNFα gene in primary cultured rat hepatocytes. As for the expression of early-response genes, 1 μM nodularin or microcystin-LR induced expression of the c-jun,  jun B, jun D, c-fos, fos B and fra-1 genes in the hepatocytes, and the expression of these genes was prolonged up to 24 h, suggesting mRNA stabilization induced by inhibition of protein phosphatases 1 and 2A. This paper presents new evidence that the TNFα gene and early-response genes were expressed in hepatocytes treated with a liver tumor promoter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372544
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  • 2
    Electronic Resource
    Electronic Resource
    Expression of the tumor necrosis factorα gene and early response genes by nodularin, a liver tumor promoter, in primary cultured rat hepatocytes (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 413-419 
    Details
    ISSN: 1432-1335
    Keywords: Tumor necrosis factor α ; Early-response genes ; Liver carcinogen ; mRNA stabilization ; Protein phosphatase inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nodularin is a new liver carcinogen possessing a potent tumor-promoting activity in rat liver, mediated through inhibition of protein phosphatases 1 and 2A, and a weak initiating activity. Since we previously reported evidence that nodularin up-regulated expression of the tumor necrosis factor α gene (TNFα) and early-response genes in rat liver after its i.p. administration, and since TNFα had tumor-promoting activity in vitro, it is possible that TNFα itself is involved in liver tumor promotion. We investigated whether hepatocytes themselves induce expression of theTNFα gene and early-response genes in primary cultured rat hepatocytes treated with nodularin. Like nodularin, microcystin-LR, which is another liver tumor promoter belonging to the okadaic acid class, strongly inducedTNFα gene expression in rat hepatocytes, as well as TNFα release from those cells into the medium. On the other hand, 12-O-tetradecanoylphorbol-13-acetate, which has been reported to induce no tumor promotion in rat liver, induced no apparent expression of theTNFα gene in primary cultured rat hepatocytes. As for the expression of early-response genes, 1 μM nodularin or microcystin-LR induced expression of the c-jun, jun B,jun D, c-fos, fos B andfra-1 genes in the hepatocytes, and the expression of these genes was prolonged up to 24 h, suggesting mRNA stabilization induced by inhibition of protein phosphatases 1 and 2A. This paper presents new evidence that theTNFα gene and early-response genes were expressed in hepatocytes treated with a liver tumor promoter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372544
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  • 3
    Electronic Resource
    Electronic Resource
    Kinematics and deformation characteristics as a mixing measure in the screw extrusion process (1994)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 34 (1994), S. 174-189 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The present paper proposes “Deformation Characteristics” (DC) as a new deformation measure of screw extrusion processes, based on the Green deformation tensor. In contrast to previous strain measures heuristically proposed by Mohr, et al., Mckelvey, and Pinto and Tadmor, the new DC can naturally incorporate the demixing phenomena and systematically take into account the three-dimensional circulatory flow with the screw flight effect. Therefore, DC can be regarded as an improved strain measure. “Weighted Average Deformation characteristics” (WADC) is also proposed to indicate the overall deformation characteristics as a quantitative measure to the “goodness of mixing” of the extrusion process. The present paper includes discussion on delicate differences between DC and several other strain measures in case of the two-dimensional velocity approximation, and on the application of DC into a general three-dimensional velocity field obtained by a quasi-three-dimensional finite element analysis of extrusion processes. In determining WADC in the three-dimensional application, the residence time distribution function, including the three-dimensional circulatory flow effect, is used.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760340303
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  • 4
    Electronic Resource
    Electronic Resource
    A simple approach to determining three-dimensional screw characteristics in the metering zone of extrusion processes using a total shape factor (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 274-283 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is of great importance in designing extruders to predict the screw characteristics, that is, the throughput in terms of the screw speed and the pressure gradient along the down-channel direction. The screw characteristics depend on the extruder geometry, the operating conditions, and material properties of non-Newtonian fluids. This paper suggests a simple approach to determining the screw characteristics for a three-dimensional flow in a channel with a finite aspect ratio (ratio of a width to a depth, W/H) by introducing a Total Shape Factor (Ft) to correct a two-dimensional flow analysis for a channel with an infinite aspect ratio. In the present study, the Total Shape Factor (Ft) was defined as a ratio of a net flow rate obtained by the three-dimensional analysis to that by the two-dimensional analysis. In the proposed approach, the quantity, ∂Ft/∂(H/W), which turns out to be almost constant, offers important information for understanding the effects of the flights. Threfore, ∂Ft/∂(H/W) is extensively reported in this paper in terms of several dimensionless parameters. This simple approach with such a database will be very useful for extruder designers to predict screw characteristics.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350308
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  • 5
    Electronic Resource
    Electronic Resource
    Graphical approach to non-ideal cases of self-associating protein systems (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 197-214 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Our previous paper described graphical procedures for evaluating the mode of association in ideal discrete and indefinite cases. This paper concerns the application of such procedures in cases where the non-ideality term BM1 must be considered. Bovine liver L-glutamate dehydrogenase and lysozyme are used as model systems. Several graphical procedures for dealing with cases of 1 - m, 1 - m - n, or indefinite association are developed. The procedure is based on the evaluation of the weight-fraction monomer with-out prior calculation of BM1, using graphical analysis to evaluate the non-ideality term.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110115
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  • 6
    Electronic Resource
    Electronic Resource
    Enhancement of mixing performance of single-screw extrusion processes via chaotic flows: Part II. Numerical study (1996)
    Hoboken, NJ : Wiley-Blackwell
    Advances in Polymer Technology 15 (1996), S. 55-69 
    Details
    ISSN: 0730-6679
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In the accompanying article, Part I, we have described the basic mechanism of chaotic mixings due to a new “Chaos Screw” in single-screw extrusion processes, and presented experimental evidence of the chaotic mixing in a single-screw extruder with a typical Chaos Screw installed. The present article, Part II, will be focused on the numerical investigations of the chaotic flows via the Chaos Screw in a single-screw extruder. The three-dimensional velocity fields in both the no-barrier and barrier regions were separately calculated via a finite element analysis of the quasi-three-dimensional flow in each region, and were subsequently used in the numerical simulations of chaotic flow behaviors. Extensive numerical simulation results will be presented in terms of particle trajectories, Poincaré sections, and mixing patterns for several dimensionless parameters. It was found that invariant manifolds obtained by numerical simulations were in good agreement with those from experiments. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Enhancement of mixing performance of single-screw extrusion processes via chaotic flows: Part I. Basic concepts and experimental study (1996)
    Hoboken, NJ : Wiley-Blackwell
    Advances in Polymer Technology 15 (1996), S. 41-54 
    Details
    ISSN: 0730-6679
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: As far as the mixing performance in single-screw extrusion processes is concerned, it is well known that the deformation measure or stretching which materials undergo due to the regular flows inside a conventional screw channel increases linearly with the extruder channel length. In general, the chaotic mixing is far superior to the regular mixing. Therefore, it would be fascinating if one could make the chaotic mixing possible in single-screw extruders with a special, and yet easily manufacturable screw without sacrificing the pumping performance of single-screw extruders. With this purpose in mind, we have developed a new screw (termed “Chaos Screw”) for the single-screw extrusion process to enhance the mixing performance via the chaotic flows. The main idea of the Chaos Screw design lies in the spatially periodic barriers inserted in the channel to break closed streamlines in regular flows, which induces the chaotic mixing. The present article describes the basic mechanism of the chaotic mixing in a single-screw extruder and presents experimental evidence of the chaotic mixing using the Chaos Screw. Experimental mixing patterns due to the chaotic flow clearly indicate that the Chaos Screw drastically enhances the mixing performance in a single-screw extruder. It may be mentioned that the accompanying article, Part II, presents numerical investigation which shows that the chaotic mixing was successfully predicted by numerical simulations. © 1996 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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