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  • 1
    Electronic Resource
    Electronic Resource
    A direct automated procedure for frictionless contact problems (1982)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 18 (1982), S. 245-257 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The solution of elastostatic bodies in frictionless contact is obtained by an automated direct method which exploits the theory of linear elasticity and circumvents the need for the inclusion of artificial interface elements, mathematical programming techniques or computation of contact pressure. The method is simple and economical to use and can be easily appended to existing numerical schemes such as the finite element method. The formulation and numerical algorithm are presented for body combinations which are independent of relative tangential displacements along the contact surface. The method is illustrated through an elementary example amenable to hand calculation. Numerical results for more realistic problems are given and compared to known solutions. It is concluded that the method provides a powerful means for both the analysis and design of contacting bodies when used in conjunction with a finite element computer program.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620180207
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  • 2
    Electronic Resource
    Electronic Resource
    Improvements in 3-node triangular shell elements (1986)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 23 (1986), S. 1643-1667 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Low-order triangular finite shell elements are computationally economical and easy to implement, but often exhibit very slow convergence. Two new membrane formulations for triangular shell elements are examined which rectify these drawbacks. The first element is based on the Marguerre shallow shell theory and a strain projection method that eliminates spurious membrane strain energy. Resulting expressions are provided in an explicit form for easy implementation of the element. The second element is based on a linear membrane field governed by normal rotations and reduced quadrature.The difficulties with shell-normal rotations are analysed and a method for omitting these rotations while preserving rigid body motion is presented and tested. Finally, a set of test problems are examined which show the importance of mesh patterns and degrees-of-freedom per node on triangular element performance.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620230906
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  • 3
    Electronic Resource
    Electronic Resource
    An analysis of solidification problems by the boundary element method (1987)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 24 (1987), S. 1879-1900 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The problem of interest in this paper is the calculation of the motion of the solid-liquid interface and the time-dependent temperature field during solidification of a pure metal. An iterative implicit algorithm has been developed for this purpose using the boundary element method (BEM) with time-dependent Green's functions and convolution integrals.The BEM approach requires discretization of only the surface of the solidifying body. Thus, the numerical method closely follows the physics of the problems and is intuitively very appealing.The formulation and the numerical scheme presented here are general and can be applied to a broad range of moving boundary problems. Emphasis is given to two-dimensional problems. Comparison with existing semi-analytical solutions and other numerical solutions from the literature reveals that the method is fast, accurate and without major time step limitations.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620241006
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  • 4
    Electronic Resource
    Electronic Resource
    The fine structure of early tooth formation in an lguanid lizard, Anolis carolinensis (1985)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 183 (1985), S. 165-176 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytodifferentiation and hard tissue formation were studied in Anolis to collect information regarding the phylogenetic history of enamel and the functional significance of the events seen in the mammalian tooth during differentiation. The differentiation of the ameloblasts of Anolis, like that of mammals, shows two phases: In the early phase, the cells are short and rich in free ribosomes, in the late phase the cells elongate, develop an extensive rough endoplasmic reticulum, and the Golgi apparatus moves into that part of the cell next to the basal lamina (the cell apex). The early epithelial-mesenchymal interface resembles that of mammals, suggesting that early mechanisms of induction and epithelial-mesenchymal interaction are similar in Anolis and in mammals.Preameloblast processes and preameloblast-preodontoblast contacts in Anolis are rudimentary compared to those of mammals. While in mammals the preameloblast processes shape the future DEJ (dentin-enamel junction), their involvement in establishing the shape of the DEJ of Anolis is questionable. We suggest that the great development of preameloblast-preodontoblast contacts in mammals may simply increase the efficiency of inductive interactions between these cell types.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051830205
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  • 5
    Electronic Resource
    Electronic Resource
    The ovarian cycle of the ring dove (Streptopelia risoria)Paper no. 349 from the Department of Genetics, Wisconsin Agricultural Experiment Station. (1945)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 77 (1945), S. 351-377 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050770305
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  • 6
    Electronic Resource
    Electronic Resource
    A light microscopic study of the mononuclear cells infiltrating skin homografts in the garter snake, Thamnophis sirtalis (Reptilia: Colubridae)Submitted to the State University of New York, Upstate Medical Center, in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Supported by Training grant GM-00326 and Research grant HD-03484 from the National Institutes of Health. (1972)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 137 (1972), S. 149-159 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The rejection of skin homografts in the snake, Thamnophis sirtalis is preceded by an infiltration of mononuclear cells into the graft bed. The initial arrangement of infiltrating cells in perivascular halos suggests that these cells emigrate from the blood stream of the host. A cytological study showed that the vast majority of the cells can be classified as small and mediumsized lymphocytes, monocytes and macrophages. Early stages of infiltration were associated with large proportions of lymphocytes while later stages were characterized by a predominance of macrophages. It was concluded that the mononuclear cells associated with graft rejection include large proportions of lymphocytes and macrophages and not just one kind of lymphoid cell.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051370203
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  • 7
    Electronic Resource
    Electronic Resource
    Fine structure of oocyte maturation in a crinoid echinoderm, Oxycomanthus japonicus: A time-lapse study by serial biopsy (1988)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 198 (1988), S. 205-217 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Natural maturation of the oocytes of Oxycomanthus japonicus can be predicte in advance, and the multiple ovaries permit unintrusive serial biopsies. Ovaries were fixed for transmission electron micrscopy at 15-min intervals before, during, and after oocyte maturation. The start of maturation of each oocyte is signaled by the breakdown of the germinal vesicle and the disruption of a macula adhaerens associating the oocyte with nongerminal cells of the ovary. This disruption is followed by an ovulation of the oocyte into the ovarian lumen. Ovulation takes about 1 hr, and a continuous vitelline coat is produced around the oocyte during this interval. Within the oocyte cytoplasm, patches of nuage and the annulate lamellae disappear at 30 and 45 min after the start of oocyte maturation, respectively. Micropapillae become transiently abundant at the oocyte surface both at the time of germinal vesicle breakdown and around the time when the first and second polar bodies are produced. Oocyte maturation takes about 2 hr from start to finish, and the emission of the second polar body marks the beginning of the stage of the ovum. Within the cytoplasm of the ovum, the haploid chromosomes develop into chromosome-containing vesicles, which later fuse into a single female pronucleus. Pronuclear ova are retained in the ovarian lumen for about 1 hr and are then spawned into the surrounding seawater, where fertilization takes place.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051980207
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  • 8
    Electronic Resource
    Electronic Resource
    Tubulin dimer formation via the release of α- and β-tubulin monomers from multimolecular complexes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 222-230 
    Details
    ISSN: 0886-1544
    Keywords: native electrophoresis ; tubulin isotypes ; dimerization ; complexes ; GTP binding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The functional subunit of microtubules is a heterodimer consisting of α- and β-tubulin. An understanding of tubulin dimerization has been hampered because it has not proved possible to purify native tubulin monomers. To study the process whereby tubulin dimers are formed, we made use of tubulins synthesized by in vitro transcription and translation. We present evidence that the in vitro synthesis of different mouse α-tubulin isotypes involves a multimolecular complex. The synthesis of mouse β-tubulin isotypes also involves the formation of multimolecular complexes, though different isotypes behave somewhat differently from one another. The properties of in vitro synthesized α- and β-tubulin multimolecular complexes strongly suggest that they are intermediates in the biosynthesis of tubulin monomers. Upon release, these monomers can exchange with pre-existing tubulin heterodimers. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230306
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  • 9
    Electronic Resource
    Electronic Resource
    Involvement and relative importance of at least two distinct mechanisms in the effects of 2-mercaptoethanol on murine lymphocytes in culture (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 40-45 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 2-Mercaptoethanol (2-ME) exerts several effects on murine lymphocytes in culture that might explain its ability to enhance survival and growth of these cells. The uptake of the essential amino acid cystine and consequently the maintenance of intracellular glutathione levels are enhanced by 2-ME. Furthermore, 2-ME (even in the disulfide form) causes lymphocytes to release thiols into the culture medium. These effects might protect the cells from oxidative damage. The additional cystine provided by treatment of lymphocyte cultures with 2-ME might also allow adequate protein synthesis to support survival and/or growth. This study was conducted to assess the relative importance of the antioxidant and protein synthesis effects of 2-ME. As expected, 2-ME increased cystine uptake at all concentrations that enhanced growth and survival, but four nonthiol antioxidants that enhanced growth and/or survival either did not substantially affect cystine uptake or decreased it and did not affect the release of cystine or its products. The results presented here demonstrate that antioxidant protection is necessary and sufficient for lymphocyte survival and that cystine uptake in untreated lymphocytes is sufficient to support the protein synthesis needed for survival and limited growth. However, we also noted that concentrations of 2-ME that stimulated maximal growth more than doubled protein synthesis as measured at 8 hr. Thus the portion of the effects of 2-ME not accounted for by antioxidant action could be accounted for by enhanced protein synthesis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041410107
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  • 10
    Electronic Resource
    Electronic Resource
    Pulmonary alveolar macrophages express a polyamine transport system (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 139 (1989), S. 624-631 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Polyamine transport is an important mechanism by which cells regulate their intracellular polyamine content. It is well established that the lung has a high capacity for polyamine transport, and recently the polyamine putrescine has been shown to be selectively accumulated into the type II pneumocyte of rabbit lung slices (Saunders et al.:Lab. Invest., 95:380-386, 1988). In addition, it has been suggested that there may be more than one polyamine transport system in lung tissue (Byers et al.:Am. J. Physiol., 252:C663-C669, 1987). In the present study, we have examined whether there are differences in the distribution of putrescine and spermidine uptake activities in isolated rabbit lung cells. We report that pulmonary alveolar macrophages have a greater rate of uptake of both putrescine and spermidine than the total lung cell population. Kinetic analysis of the polyamine uptake system present in macrophages showed putrescine uptake consisted of a saturable (Km = 2.1 μM) and nonsaturable component whilst spermidine uptake consisted of both a high- and a low-capacity saturable component (Km = 0.16 μM and 1.97 μM, respectively). The rate of polyamine transport was similar to those reported for many proliferative or tumor cell-lines and appeans to be greater than any other major lung cell type. Inhibition studies of the transport of polyamines into pulmonary alveolar macrophages suggested that the uptake of both putrescine and spermidine was mediated by the same system, which could not be described by simple Michaelis-Menten kinetics. The transport appears to be reversible due to significant efflux. This is the first study to describe the presence of multiple polyamine transport systems in pulmonary alveolar macrophages.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041390324
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