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  • 1970-1974  (5,020)
  • Life and Medical Sciences  (2,378)
  • Industrial Chemistry  (1,865)
  • Engineering General  (489)
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Year
  • 101
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 743-770 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The discrete (Legendre) orthogonal polynomials, (DLOP's) are useful for approximation purposes. This set of mth degree polynomials {Pm(K, N)} are orthogonal with unity weight over a uniform discrete interval and are completely determined by the normalization Pm(O, N) = 1. The authors are employing these polynomials as assumed modes in engineering applications of weighted residual methods. Since extensive material on these discrete orthogonal polynomials, and their properties, is not readily available, this paper is designed to unify and summarize the presently available information on the DLOP's and related polynomials. In so doing, many new properties have been derived. These properties, along with sketches of their derivation, are included. Also presented are a representation of the DLOP's as a product of vectors and matrices, and an efficient computational scheme for generating these polynomials.
    Additional Material: 5 Tab.
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  • 102
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 783-801 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The patch test is shown to be contained in the variational formulations of the finite element methods at the assembling level, all of which require the vanishing of the virtual work of interface connection loads. By a systematic introduction of stress generating functions, attention is drawn to the fact that any given finite element model can be assembled in two different ways: either by identification of a set of boundary displacements (leading to the direct stiffness method), or by identification of a set of local stress function values (leading to the dual direct flexibility method). Looking at any conjugate couple (generalized displacement-generalized surface traction) at an interface, one is strongly transmitted, the other weakly. Discretization of the zero virtual work condition at an interface of plate bending models, by means of Legendre polynomial expansions, allows a systematic construction of so-called ‘non-conforming’ elements that pass the patch test. They are in fact identified with weakly conforming, but strongly diffusive, hybrids, and the lowest degree element (quadratic) is in fact the Morley constant-moment element. Examples are given for higher degree displacement fields.The case of plate stretching elements can be handled by duality, the difficulties being here associated with the requirements for diffusivity. Non-diffusive elements that pass the zero interface virtual work test can be constructed systematically and are identifiable with weakly diffusive, but strongly conforming, hybrids of the type first proposed by T. H. H. Pian.
    Additional Material: 6 Ill.
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  • 103
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974) 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 104
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 27-43 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Body oriented co-ordinates are defined for three-dimensional regions bounded by six surfaces. From this definition of body oriented co-ordinates, two transformations are derived: 1Body oriented surface co-ordinates to the Cartesian co-ordinates, and2Body oriented co-ordinates for a three-dimensional region to Cartesian co-ordinates.With these transformations a mesh generator is developed based on the principle that the mesh required to describe a region will be calculated according to the placement of the discrete points that describe the boundary edges. This is accomplished with two versions of the mesh generator: the surface generator and the volume generator. The surface generator maps the four boundaries of the surface onto the four boundaries of a unit square. Next, the interior points for the surface mesh are established in the mapped space. Then, using the first transformation, the co-ordinates for the surface nodal points are calculated. Similarly, the volume generator maps the six surfaces of the body onto the surfaces of a unit cube, establishes the interior nodal points in the mapped space, and using the second transformation, calculates the co-ordinates for the interior nodal points.
    Additional Material: 11 Ill.
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  • 105
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 359-367 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper describes a method of solving electromagnetic induction problems by means of the finite element technique. A variational equation associated with the differential equation for the vector potential is formulated and solved via the concept of finite elements. Sinusoidal driving currents and linear, isotropic, but inhomogeneous media are assumed. A typical example is included in order to illustrate the suggested solution technique.
    Additional Material: 1 Ill.
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  • 106
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 369-394 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The mesh generation program described here generates the nodes and the elements for excavated highway slopes, applies boundary conditions, searches for the nodes and the elements in each layer excavated and plots the mesh with the numbering of nodes, elements and material types.
    Additional Material: 5 Ill.
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  • 107
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 415-424 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element analysis applicable to elasto-plastic shells of arbitrary shape is presented. Small-deflection behaviour of thin shells subjected to monotonically increasing static loads is considered. The material is assumed to be originally isotropic, following the von Mises yield criterion and the Prandtl-Reuss flow rule. A flat triangular element with twelve degrees of freedom is used in the analysis. Within each element both membrane forces and bending moments are assumed to be constant. Some numerical results are included to illustrate the merits of the element.
    Additional Material: 8 Ill.
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  • 108
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 425-429 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A procedure to deal with various boundary conditions in the Rayleigh-Ritz method is discussed herein, namely, the method of artificial parameters. The method is then applied to solve a simple string problem; results obtained compare very nicely with exact solutions.
    Additional Material: 3 Ill.
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  • 109
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 431-432 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 110
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 433-437 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: One of the first finite elements presented was that by Turner et al.1 Pian2 presented a hybrid plane stress element and Wilson et al.3 presented a non-conforming displacement element. It is shown that the three resulting stiffness matrices are identical.
    Additional Material: 2 Ill.
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  • 111
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 461-480 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The concepts and potential advantages of local and global least squares smoothing of discontinuous finite element functions are introduced.The relationship between local smoothing and the ‘reduced’ integration' technique is established.Examples are presented to illustrate the application of the two smoothing techniques to the finite element stresses from several structural analysis problems.The paper concludes with some practical recommendations for discontinuous finite element function smoothing.
    Additional Material: 12 Ill.
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  • 112
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 495-501 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In a two-dimensional space of points on an equilateral triangle grid, a single difference equation holding at each node is found from the finite element formulation of the wave equation for all published polynomial orders of the functional expansion. Assuming homogeneous boundary conditions on any equilateral triangle whose edges and vertices pass through the grid points, the eigensolutions of the difference equation are found exactly and thus provide an excellent test problem for the programmer or engineer. The advantage of the present method over other formulations is that the number of linear operations required to produce the difference equation is minimal.
    Additional Material: 3 Ill.
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  • 113
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 429-430 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 114
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 432-432 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 115
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 438-438 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 116
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 443-460 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A number of problems are analysed by the displacement method to assess the stress accuracy at very low compressibilities. ‘Parabolic’ isoparametric elements are used. It is found that the mean stress becomes grossly in error at the centre and edges of each element as the compressibility is reduced whereas the deviatoric stress components do not. All stress components retain good accuracy at the ‘reduced’ integration sampling points (2 × 2 Gauss). ‘Exact’ integration yields a similar stress distribution to ‘reduced’ but the mean stress is grossly in error at the integration points (3 × 3 Gauss). Exceptions, however, occur.These findings are interpreted, and a rule for predetermining whether or not accurate stresses can be obtained at the integrating points is suggested. Thus it is shown that the displacement method is suitable for analysing materials which for practical purposes are incompressible.A procedure is then presented for analysing porous media-both linear and non-linear-by separating the stiffness into ‘effective’ and ‘pore fluid’ components. This allows excess pore pressure to be calculated explicitly. Applications to saturated soils are given which make use of the findings of the first part of the paper.
    Additional Material: 10 Ill.
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  • 117
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 529-536 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The steady state flow problem known in magnetohydrodynamics as Hartmann's flow is converted into variational formulation and is given an approximate solution by means of the spline blended interpolation technique. The equations of motion consist of two coupled potential flow problems with homogeneous boundary conditions. The spline blended interpolation method is reduced here, because of the shape of the domain, to a cartesian product of cardinal splines with trigonometric or ordinary polynomials. ‘Exact’ boundary conditions are presented by the blending technique. The numerical results indicate that high accuracy is possible with relatively few unknowns.
    Additional Material: 4 Ill.
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  • 118
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 613-624 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The paper presents a generally applicable approach to transient heat conduction problems with non-linear physical properties and boundary conditions. An unconditionally stable central algorithm is used which does not require iteration.Several examples involving phase change (where latent heat effects are incorporated as heat capacity variations) and non-linear radiation boundary conditions are given which show very good accuracy.Simple triangular elements are used throughout but the formulation is generally valid and not restricted to any single type of element.
    Additional Material: 7 Ill.
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  • 119
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 625-631 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A program is demonstrated which apart from linear finite elements in time also includes elements with shape functions of the second and third degree. The algorithm for discretization in the time dimension is described and, using the example of a parabolic time element, the coefficients required to form the global system are given. By various test examples the efficiency of the process is examined by comparison with the customary difference method. Generally, with finite elements in time, the solution has better stability. Comparing the time required for calculation with the accuracy of the solution it would appear that in examining problems where boundary conditions are constant in time, higher order time elements are no improvement over the linear time element. However, for the purpose of reproducing periodic processes, higher order time elements offer an advantage in that one is not limited to linear variations of the boundary conditions within the element. Thus, for example, the temperature curve for parabolic variation of the surface temperature can be reproduced with close approximation by two time elements per period and a shape function of the third degree.
    Additional Material: 6 Ill.
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  • 120
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 676-676 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 121
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 771-781 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The steady two-dimensional, viscous, electrically conducting flow around a circular cylinder is investigated. The flow and magnetic field are uniform and parallel at large distances from the cylinder. The equations and boundary conditions are derived for arbitrary values of R, Rmand β, where R is the Reynolds number, Rm the magnetic Reynolds number and β, the ratio of the square of the Alfvén speed to the square of the main stream speed. Because of the large number of parameters involved, the numerical solution is restricted to R = 40, Rm = 1 and infinity and 0 ≤ β ≤ 4. Also the cylinder is taken to be a perfect conductor, this avoids having to compute the magnetic field within the cylinder.The numerical computations for the non-magnetic case, i.e. β = 0, are presented and are found to be in good agreement with existing results. The effect of increasing the strength of the magnetic field (i.e. increasing β) on the drag coefficient, the size and position of the standing vortex and the increasing effect of the upstream propagation of disturbances are examined.
    Additional Material: 5 Ill.
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  • 122
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 811-820 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: We describe a finite element method for the one-dimensional Stefan problem. The elements are quadrilaterals of the space-time plane which are determined at each time-step in relation with the position of the free boundary. The method appears as a generalization of the classical Crank-Nicolson scheme, since it is identical to this scheme in the case of rectangular elements; it has the advantage of providing a simple and accurate determination of the free boundary. Numerical experiments show that the order of accuracy is equal to 2.
    Additional Material: 2 Ill.
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  • 123
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 865-876 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Based on the least squares error criterion, a class of finite element is formulated for the numerical analysis of steady state viscous boundary layer flow problems. The method is essentially a discrete element-wise minimization of square and weighted residuals which arise from the attempts in approximately satisfying boundary layer equations. An iterative linearization scheme is developed to circumvent the mathematical difficulties posed by the non-linear boundary layer equations. It results in a process of successive least squares minimizations of residual errors arising from satisfying a set of linear differential equations. A mathematical justification for the method is presented. A major feature of the method lies in the linearization approach which renders non-linear differential equations amenable to linear least squares finite element analysis. Another important feature rests on the proposed finite element formulation which preserves the symmetric nature of finite element matrix equations through the use of the least squares error criterion. Numerical examples of viscous flow along a flat plate are presented to demonstrate the applicability of the method as well as to illuminate discussions on the theoretical aspects of the method.
    Additional Material: 8 Ill.
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  • 124
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 917-917 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 125
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 847-864 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite beam-column element computer program for the structural failure analysis of proportionally loaded skeletal plane frames is described. The program, which is based on an iterative stiffness approach, provides for non-linear elastic or plastic-non-linear elastic behaviour. Particular attention is given to the incorporation into the analysis of geometrical imperfections, return of elasticity at plastic hinges and negative frame stiffness. The effect of lack-of-fit displacements on the load-deflection path and failure load of frames that carry relatively large axial loads is described in general terms. The theory is developed further through the application of the computer program to two examples which show the necessity for the allowing for the effect of imperfections when designing axially loaded redundant frames.
    Additional Material: 9 Ill.
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  • 126
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This article presents an efficient numerical algorithm a complete listing of the associated computer program, developed for the eigenproblem solution of discrete damped structures, including spinning ones. The numerically stable procedure is based on a combined Sturm sequence and inverse iteration technique, which fully exploits the banded form of the relevant matrices and proves to be most substantially economical when compared to similar existing softwares. Numerical results are presented for representative structures, solved by the present computer program written in FORTRAN V for the JPL UNIVAC 1108 computer.
    Additional Material: 4 Ill.
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  • 127
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 17-25 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Three variational statements for the slow time-independent flow of a Navier-Poisson fluid are derived. All of these statements are suitable as the bases of finite elements. The first statement is applied successfully to several flow situations.
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  • 128
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 91-102 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper deals with the numerical solution of wave propagation problems in general although the primary area of interest is elastodynamics. The work is applicable to a variety of wave propagation phenomena of classical physics. Explicit schemes of Strang type are used, which allow many simplifications over existing methods. The Strang schemes allow in a very real but perhaps unexpected way the splitting of the elasticity operator.
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  • 129
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 71-90 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: By use of the least squares error criterion, an alternate finite element formulation is presented. The method is based on the discrete or element-wise minimization of square and weighted differential equation residuals which are expressed in terms of element nodal quantities. In order to overcome the stringent inter-element continuity requirement, a major stumbling block, on the element trial functions two practical schemes are proposed. One is the reduction of the original governing differential equation to a system of equivalent first order differential equations; the other is a method of smoothing discontinous trial functions. The latter essentially relaxes the continuity requirement and yields efficient non-conforming finite elements. This paper also demonstrates the use of constant weights which significantly improves the rates of convergence. Several numerical examples illustrate the proposed method. From these examples, it may be concluded that the use of constant weights and the relaxation of the inter-element continuity requirement are two indispensable features of the weighted discrete least square method.
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  • 130
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 119-138 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A direct method is described for the evaluation of the critical loads on deep circular arches having various forms of end support. The method is applicable to arches of non-uniform flexural rigidity and may cater for arbitrary forms of applied load distribution. The results calculated for two examples are given, and compared with those obtained analytically and experimentally by other investigators. A complete listing of a computer program for one of the examples is provided in the Appendices.
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  • 131
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 195-198 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element method for the analysis of axisymmetric bodies in torsion is presented. The effects of an angular acceleration about the axis of symmetry is included. The accuracy of the method is tested against experimental results available for a stepped shaft and finally the problem of an accelerating shaft-turbine disc system is considered.
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  • 132
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 1-16 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: When large, progressive, deformation occurs under plastic or visco-plastic conditions, elastic deformations are negligible and the material flows in a viscous manner. The flow is non-Newtonian and the viscosity is a function of the current strain rates. An effective numerical treatment of such non-Newtonian flow by the finite element method is indicated here and is illustrated by examples of an extrusion process for which approximate slip line solutions are known.The methodology is extended to the solution of transient, quasi-static situations and coupling with thermodynamic equations is discussed.A stream function formulation of the problem is used.
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  • 133
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 55-69 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The finite element method is applied to dynamic linear viscoelastic analysis. The arising system of differential equations is integrated by means of the Laplace transformation. The direct numerical evaluation of the inversion integral seems to be appropriate in case of vibrational problems. The method is applied to examples of transient vibrations of elastic bodies. Initial conditions and arbitrary damping matrices can be considered.
    Additional Material: 6 Ill.
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  • 134
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 103-110 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper discusses three numerical integration schemes connected with a finite element solution to the transient heat-conduction equation. The main emphasis is on the achievable accuracy. A simple recurrence relation derived from the Galerkin process is suggested for the treatment of fast-varying boundary conditions as being significantly better than the usual Crank-Nicholson scheme in matters of short-time accuracy.
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  • 135
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 167-194 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Use of mixed force and displacement variables may be the key to a reliable solution of many physical problems. For the analysis of elastic structures with large rigid motion the displacement method may fail due to illconditioning, but use of mixed variables (diacoptics) may work due to the possibility of using relative displacements within substructures. Analysis with mixed variables complicates the topology (the number of nodes and the number of variables at the nodes may vary in the same problem) so a careful study of the system analysis is required. Some general computer routines are given for handling topology, merging and solution of the sparse system equation. The solution routine handles constraints in a rational way and can also be used for decomposition of the system equation or for releasing inner nodes in superelements.
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  • 136
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 198-203 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The application of the static condensation method is discussed in general. The technique is presented as an extension of the Gauss elimination algorithm. An efficient FORTRAN subroutine is given which simultaneously reduces both the stiffness matrix and the stress-displacement transformation matrix.
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  • 137
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 212-212 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 138
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    International Journal for Numerical Methods in Engineering 8 (1974) 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 139
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 227-248 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An integrated sequential computer programme for the solution of large linear algebraic systems encountered in the discrete analysis of complex structures using finite element idealization is described. The programme uses an algorithm based on Gauss elimination for solution and is independent of the possible symmetric nature of the system matrix thus enhancing the applicability of the programme for systems with unsymmetric coefficient matrices. The present programme can handle large band widths and the core memory is used efficiently for all feasible problem sizes. A FORTRAN print-out of the programme with relevant explanatory comments and a full notation list are appended.
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  • 140
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 521-528 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Two methods are presented for the automatic selection of a cycle basis leading to a sparse flexibility matrix for the analysis of rigid-jointed skeletal structures.The first method having a local approach forms a maximal set of admissible minimal cycles, while the second having a global approach constructs admissible minimal cycles on the ordered chords of a shortest route tree. A cycle ordering algorithm is also given to reduce the band width of the corresponding flexibility matrix.
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  • 141
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 589-611 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper presents a method of solving systems of simultaneous non-linear partial differential equations using the method of lines and the method of quasilinearization-superposition in combination. The advantages of the method over those methods more generally used are discussed and an example of the application of the method to the two-dimensional momentum and energy equations considering temperature-dependent and/or shear-rate dependent viscosity is given.
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  • 142
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 649-657 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 143
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 633-647 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The method of ‘least squares’, which falls under the category of weighted residual processes, is applied as a time-stepping algorithm to one-dimensional transient problems including the heat conduction equation, diffusion-convection equation, and a non-linear unsaturated flow equation. Comparison is made with other time-stepping algorithms, and the least squares method is seen to offer definite advantages.
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  • 144
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 676-676 
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    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 145
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 679-696 
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    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The object of this paper is to describe a new algorithm for the semi-automatic triangulation of arbitrary, multiply connected planar domains. The strategy is based upon a modification of a finite element mesh genration algorithm recently developed. 1 The scheme is designed for maximum flexibility and is capable of generating meshes of triangular elements for the decomposition of virtually any multiply connected planar domain. Moreover, the desired density of elements in various regions of the problem domain is specified by the user, thus allowing him to obtain a mesh decomposition appropriate to the physical loading and/or boundary conditions of the particular problem at hand. Several examples are presented to illustrate the applicability of the algorithm. An extension of the algorithm to the triangulation of shell structures is indicated.
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  • 146
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 731-741 
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    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A polynomial shape function of triangular elements for finite element analysis of general deformation of sheet metals with or without orthotropic anisotropy is proposed. And general formulation for large deformation and large strain analysis with non-linearity of material property, say plasticity, is given. Some numerical examples are examined with respect to hydraulic bulging.
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  • 147
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 713-729 
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    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A characteristic feature of the variational functionals for several boundary value problems in polar co-ordinates is the fact that one independent variable occurs explicitly in the denominator. Therefore, the coefficients of the finite element equations for sectors of circular ring shaped elements are not constants but functions of the distance of the elements from the origin of co-ordinates.1 We name them coefficient functions. In order to show the particular aspects of the calculations in terms of polar co-ordinates we deal here with the solution of the torsion problem by bilinear and bicubic Hermitian interpolation.The finite element equations are arranged according to Schaefer2 in the form of block which can easily be transformed into ‘stars’3 or molecules4,5 similar to those used in finite difference methods. The origin of co-ordinates requires a special consideration, firstly because of the coincidence of several nodes at that point and secondly because of the divergent behaviour of some coefficient functions. It turns out to be advantageous for the numerical calculations to expand the coefficient functions in power series. Besides, the expansions are required to deduce the equations for rectangular elements by limiting processes. The twisting moments and shearing stresses calculated for several cross sections illustrate the numerical suitability of the method. The finite element values are compared partly with exact solutions and partly with experimental results obtained by a moiré method using Prandtl's soap film analogy.6 Finally it is shown how the accuracy of the finite element values can be improved by the Richardson extrapolation7.
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  • 148
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    International Journal for Numerical Methods in Engineering 8 (1974), S. 914-916 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The paper shows a procedure for estimating the shape parameter of a Gamma distribution from a sample. This procedure uses a rapidly converging iteration to solve the maximum-likelihood equation and suggests a simple formula for determing the starting value.
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  • 149
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    Journal of Morphology 142 (1974), S. 411-431 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cells in secretory glands of globiferous pedicellariae from Strongylocentrotus purpuratus (Stimpson) were studied with the electron microscope and subjected to preliminary light microscopic, histochemical analysis. Specimens for electron microscopic observation were fixed with chilled 2% glutaraldehyde in sea water postfixed in cold 1.33% osmic acid, and embedded in Araldite 502 epoxy resin Samples for histochemical analysis were fixed in the same manner, and then embedded in n-butylmethacrylate.Secretory cells line and fill partially bifurcated, muscular gland sacs located peripherally on each of three jaw elements comprising the pedicellarial head. Cells from venom glands are typically mucoid in appearance, possessing small volumes of basally displaced, vesiculated cytoplasm and an extensive system of vacuoles dominating the apical nine-tenths of each cell. These vacuoles enclose ground substances of various densities and staining affinities. Despite their extensive vacuolation, gland cells contain numerous cytomembrane complexes indicating metabolic activity just prior to fixation. Deciduous endoplasmic reticulum, Golgi complexes, large vacuoles, and various species of vesicles associated with these membrane systems are found in spatial proximity which indicates an apparent biosynthetic association.Preliminary histochemical tests on sections embedded in acrylic plastic indicate vacuolar products may consist of protein and nonsulfated acid mucosubstances.Gland cells are probably holocrine in function, releasing their vacuolar complement upon constriction of the muscular gland sac. There is no evidence indicating delivery of non-membrane bounded, granular secretion to an acellular lumen within the gland sac.
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  • 150
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Transmission and scanning electron microscopic studies demonstrate the stimulatory effect of synthetic salmon calcitonin on the fine structure of fibroblasts and on collagen formation in cutaneous wounds experimentally induced in rabbits. Long-term administration of calcitonin enhances fibroblast growth and collagen synthesis. The fibroblasts hypertrophy and exhibit a highly developed rough endoplasmic reticulum (RER), several polyribosomes, large nuclei, hypertrophic Golgi complex, and many dense granules and lysosomes. Mitochondria are elongate and ramify; intracellular as well as extracellular synthesis of collagen increases. Fibrils appear tightly packed, in large heaps or spicula, with a characteristic periodicity and striation.Scanning electron micrographs of topography and relationships with collagen fibers and fibrils and cells surface changes demonstrate an extensive network of fine fibrils between collagen fibers, marked ruffling of cell membranes as well as numerous blebs on the cell surface. The latter are significant in collagen formation and egestion.
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  • 151
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Sperm enter the anterior vas deferens individually in the spider crab male. There they become surrounded by secretion products from the cells of the vas deferens, and are compartmentalized into spermatophores of varying size. The anterior vas deferens can be divided into three regions. The epithelium of the anterior vas deferens varies regionally from low to high columnar. The cytoplasm contains vast arrays of rough endoplasmic reticulum and Golgi complexes but few mitochondria. Intercellular spaces contain septate junctions, gap junctions and vesicles.Once the spermatophores have been formed in the anterior vas deferens, they are moved posteriorly to the middle vas deferens where they are stored and surrounded by seminal fluids. The epithelial cells of the middle vas deferens contain large amounts of rough endoplasmic reticulum and Golgi complexes. Numerous micropinocytotic vesicles appear, forming at the cell surface and within the apical cytoplasm. Their suggested function is the resorption of secretion products of the anterior vas deferens which initiated compartmentalization of the spermatozoa into spermatophores.The posterior vas deferens functions primarily as a storage center for spermatophores until they are released at the time of copulation. Seminal fluid surrounding the spermatophores is produced in this region as well as in the middle vas deferens. The cells of this region contain vast arrays of vesicular rough endoplasmic reticulum and Golgi complexes. The cells are multinucleate. Microtubules are numerous throughout the length of the cells and appear to insert on the plasma membrane.
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  • 152
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    Journal of Morphology 143 (1974), S. 21-75 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Basicranial anatomy of mammalian carnivores is significant in the determination of carnivore evolution. One of the least understood yet most often studied features of the basicranium is the auditory bulla, a bony capsule enclosing the middle ear. Although previously believed to be formed by a tympanic bone alone, or by tympanic and entotympanic, it is shown here that the carnivore bulla is formed by three and in some cases four ontogenetic elements: tympanic, rostral entotympanic, caudal entotympanic(s). These elements in Carnivora appear to correspond to bulla elements discovered over 50 years ago by Van der Klaauw in representative species of several other orders of mammals.Increased auditory sensitivity appears to have been attained in various carnivore lineages by increase in the volume of the middle ear cavity, principally by hypertrophy of the caudal entotympanic, but also by different yet less common anatomical strategies such as invasion of the mastoid bone by the middle ear space. Five basic types of bulla among living Carnivora can be recognized, based largely on the relationship of the caudal entotympanic to the other bulla elements.Closely associated with the bulla in the auditory region are the median and promontory branches of the internal carotid artery. These branches exhibit a precise relationship to the bulla elements, particularly the rostral entotympanic. The promontory branch is much reduced or completely lacking in all living carnivores. Reduction or loss of the median branch is explained as the result of the development of arterial retia on the anastomotic artery in the orbital region. Reduction of the median branch is particularly characteristic of the aeluroid Carnivora, in which a greater proportion of the cerebral blood supply passes to the brain in the external carotid artery via the anastomotic branch, and is cooled in the orbital region by a countercurrent heat exchange mechanism formed by arterial retia closely associated with venous blood in surrounding sinuses. The arctoid and cynoid Carnivora are characterized by only rudimentary development of retia along the anastomotic artery, and the median branch is much better developed than in the aeluroids. Among arctoids, ursids parallel the aeluroids in the development of a countercurrent mechanism but employ the median branch of the internal carotid rather than the anastomotic branch of the external carotid artery.Bulla structure and nature of the carotid circulation in the auditory region can be determined from fossil Carnivora as well as for living forms. This study attempts to define basicranial anatomical patterns characteristic of living Carnivora which then can be used to trace the evolution of lineages in the fossil record.
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  • 153
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    Journal of Morphology 143 (1974), S. 77-105 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The termite gut flagellates are of interest because of their unusual motile organelles, their ability to digest cellulose, and their symbiotic relationship with prokaryotes inhabiting the insect gut. This report provides a detailed ultrastructural description of Pyrsonympha from the hind-gut of Reticulitermes flavipes.The motile axostyle is composed of 2,000-4,000 microtubules connected by cross-bridges. At its anterior end, the axostyle is associated with a “primary row” of microtubules which is associated with a fibrous network. The “primary row” is embedded in a large mass of amorphous, electron-dense material occupying the furthest anterior end of the cell. The basal bodies of the eight flagella are also embedded in this presumptive microtubule-organizing center. The flagella are associated with the cell surface throughout their length. Isolation and reactivation of the axostyle has demonstrated that although ATP dependent motility is inherent in the structure of the axostyle, its proper control may be mediated by the attachment of the axostyle to structures at the anterior end of the cell.Pyrsonympha lacks morphologically distinguishable mitochondria and Golgi complexes. The cell surface is covered by unique, previously underscribed, tubular specializations. Symbiotic microorganisms are observed associated with the cell surface and within the cytoplasm.Wood particles are taken up from the gut fluid by large phagocytic vacuoles formed at the posterior end of the cell. Even during the process of breakdown, the wood is always enclosed within the membrane of the phagocytic vacuole.The Pyrsonympha from Reticulitermes flavipes are not attached to the lining of the hind-gut and do not contain an attachment organelle, unlike the Pyrsonympha from other species of Reticulitermes.
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  • 154
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 155
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    Journal of Morphology 143 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 156
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    Journal of Morphology 143 (1974), S. 121-165 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gecko ear was studied in 36 species belonging to 24 genera. This receptor has attained an advanced level of structure and performance in this group of lizards, but there are many variations among species. To a large extent these variations follow subfamily lines as represented in Kluge's system of classification.Brief consideration is given to features of the outer and middle ear, but chief concern is with inner ear structures and their relations to auditory sensitivity as represented by the cochlear potentials.The auditory papilla is segmented, with a dorsal portion whose hair cells have their ciliary tufts attached to a tectorial membrane, and a ventral portion in which these cells form tow assemblages, one with tectorial connections and the other with connections to a line of sallets.The dorsal segment varies greatly in length and in the form of ciliary orientation. In Eublepharinae and most Gekkoninae the ciliary orientation is unidirectional, and the degree of sensitivity relates to the length of this segment. In Diplodactylinae and Sphaerodactylinae the orientation is bidirectional, and this segment functionally hardly differs from the ventral segment.Auditory sensitivity as measured in terms of the cochlear potentials shows close relations with subfamily groupings, except for the Gekkoninae in which considerable diversity is found.The evidence from structural differentiation, along with that derived from the forms of the cochlear potential functions, leads to the suggestion that these ears possess a high degree of pitch discrimination and capability for the analysis of complex sounds.
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  • 157
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mature mouse and cat peripheral nerve fibers have been examined in vitro by time-lapse photography. Some Schmidt-Lanterman clefts which were open at the start closed later; other were seen to open and then to close, some of them more than once. The implications of these movements are considered, especially in regard to the question of the passage of materials from the endoneurial connective tissue spaces to the axon.Myelin movements other than those occurring at the Schmidt-Lanterman clefts consisted primarily of the development and frequent regression of indentations of the myelin sheath. A single evagination was seen to develop and then to recede. These myelin movements suggest that previously described invaginations and evaginations of the myelin sheath, including flaps of “redundant myelin”, are not static but rather that they are in a state of movement, forming and regressing at intervals.The possible functional significance of the development and regression of myelin sheath indentations in relationship to axoplasmic flow is discussed.
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  • 158
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    Journal of Morphology 143 (1974), S. 187-245 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The authors describe the spermiogenesis of Polyxenus lagurus, a diplopod, in the male genital ducts and the transformations the spermatozoon successively undergoes in the spermatheca.The spermatozoon in the male genital ducts looks like a little barrel devoid of centriole and of any kind of rudimentary flagellum whatever. The organelles are markedly modified; cross sections present an elongated, flattened nucleus, an X-shaped body running parallel to it on the opposite side and two longitudinal mitochondrial strips interposed between them. The rest of this barrel-shaped spermatozoon is filled with peculiar Golgi formations, the spongy chambers, which open outwards through little vents.In the spermatheca the spermatozoon is quite different: it is shaped like a long ribbon. The basic structure of the spermatozoon is formed by the double folding of part of the cortical layer of the barrel-shaped spermatozoon. On the central part of this endo-skeleton are longitudinally ranged the nucleus and the acrosome flanked on both sides by a thread of mitochondria. Even in this phase the sperm has no flagellum.
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  • 159
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    Journal of Morphology 143 (1974), S. 247-257 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Several secretory and nonsecretory enzymes were localized histochemically in the main venom gland of 13 viperid snakes. All secretory cells show the intracellular oxidative enzymes succinate dehydrogenase and monoamine oxidase. The granular reactions obtained for both enzymes resemble mitochondria in distribution. Distinctive cells with a very high succinate dehydrogenase activity are dispersed among the secretory cells of all species except Atractaspis.Nonspecific acid phosphatase activity is found in the supranuclear region of the secretory cells in species that do not secrete this enzyme and throughout the cytoplasm in snakes that secrete the enzyme. Nonspecific alkaline phosphatase activity occurs in the secretory cells of those snakes whose venom shows this activity. Leucine amino peptidase (aryl amidase) activity is found in the venom and in the secretory cells of all the species.In Vipera palaestinae both the venom and the secretory cells of the main venom gland contain nonspecific esterase, L-amino acid oxidase and phosphodiesterase activities. The localization of phosphodiesterase and L-amino acid oxidase do not show major differences between glands at different intervals from an initial milking.Adenosine-monophosphate phosphatase activity is localized in the supranuclear region of the secretory cells in the glands of Vipera palaestinae and Aspis cerastes. Its activity is found in the venom of Aspis only.
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  • 160
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    Journal of Morphology 143 (1974), S. 285-305 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The three dorsal ocelli of worker honeybees have been studied by light and electron microscopy. Each ocellus has a single flattened spheroidal lens and about 800 elongated retinular cells. Retinular cells are paired and form a two-part plate-like rhabdom between their distal processes. Each rhabdomere comprises parallel microvilli projecting laterally from the apposed retinular cells. Primary receptor cell axons synapse within the ocellus with ocellar nerve fibers of two different calibers. Each ocellus has eight thick fibers ca 10 m̈m in diameter and several thinner ones less than 3 m̈m in diameter. Fine structural evidence suggests that retinular axons end presynaptically on both types of ocellar nerve fibers. Since all retinular cells apparently synapse repeatedly with the thick fibers this involves a convergence of about 100:1. Thick fibers always terminate postsynaptically within the ocellus while thin fibers terminate presynaptically on other thin fibers, thick fibers or retinular axons. Structural evidence for synaptic polarization indicates that retinular cells and thick fibers are afferent, thin fibers efferent. Thus complex processing of the ocellar visual input can occur before the secondary neurons of the three ocelli converge to form the single short ocellar nerve which runs to the posterior forebrain.
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  • 161
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    Journal of Morphology 143 (1974), S. 307-335 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The functional morphology of the forelimbs of the following African Viverridae was studied, Atilax paludinosus, Bdeogale crassicauda, Civettictis civetta, Genetta genetta, G. tigrina, Helogale parvula, Herpestes ichneumon, H. sanguineus, Ichneumia albicauda, Mungos mungo, Nandinia binotata. Their locomotory behaviour has been previously studied and described and is related to morphological differences. The osteology of all the species and the myology of three species is described. The species have been assigned to primary locomotor categories on the basis of their locomotion. These are 1, climbing, arboreal walking; 2, arboreal and terrestrial walking and jumping; 3, general terrestrial walking and scrambling; and 4, trotting. In the climbing arboreal walking category the most distinctive morphological adaptations are powerful flexors and extensors as well as a flexible plantigrade manus with retractile claws. In the arboreal and terrestrial walking category the shoulder, elbow and carpal joints are flexible and the manus has retractile claws, though the flexor and extensor musculature is insufficiently developed for controlled climbing. The trotting category is characterised by a high humero-radial index and a rigid antibrachium. The foot is digitigrade with the claws short and stout. Species in the general walking and scrambling category show many differences in the morphology of their feet, even though the proximal parts of the forelimb appear similar. Due to the restricted nature of the adaptations, these species have been assigned to secondary locomotor categories. Morphological characters typical of the locomotor categories are summarized in the discussion.
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  • 162
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    Journal of Morphology 142 (1974), S. 285-299 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gastric mucosa of both the echidna and platypus is aglandular and the lining epithelium is stratified squamous. The latter exhibits three principle layers: stratum germinativum, stratum spinosum, and stratum corneum. The cytoplasm of cells composing the first two strata of both species shows bundles of tonofibrils and numerous free ribosomes. Cells of the stratum spinosum in the platypus also show numerous dense granules limited to the peripheral cytoplasm. The stratum spinosum of both species is comprised of fusiform-shaped cells whose adjacent cell membranes show extensive interlocking. The stratum spinosum of the echidna in addition shows numerous intercellular bridges. Cells of the stratum corneum become flattened and elongate and in the echidna nuclei near the surface appear to degenerate. Cells comprising the stratum corneum of the platypus exhibit well preserved nuclei and contain scattered large granules of varying electron density. Prior to sloughing, cells near the surface of both species show a separation of adjacent cell membranes. True keratinization is not found in the gastric lining epithelium of either species and the epithelium lining of the stomach of the echidna more closely represents a form of parakeratosis. Delicate papillae containing capillaries extend considerable distances into the overlying epithelium of both species and are thought to contribute to its nutrition.
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  • 163
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    Journal of Morphology 142 (1974), S. 301-319 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The epidermis of Eisenia is covered by a cuticle and rests on a basement lamella. The cuticle, which is resistant to a variety of enzymes, is composed of non-striated, bundles of probable collagen fibers that are orthogonally oriented and are embedded in a proteoglycan matrix. The basement lamella consists of striated collagen fibers with a 560 Å major periodicity. Proximity and morphology suggest that the epidermis may contribute to both the cuticle and the basement lamella  -  that is, the single tissue may synthesize at least two types of collagen. The epidermis is a pseudostratified epithelium containing three major cell types (columnar, basal and gland) and a rare fourth type with apical cilia. The esophagus is lined by a simple cuticulated epithelium composed predominantly of a single cell type, which resembles the epidermal columnar cell. Rare gland cells occur in the esophageal epithelium, but basal cells are lacking.
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  • 164
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    Journal of Morphology 142 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 165
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    Journal of Morphology 144 (1974), S. 143-165 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cuticle of five species of Oligochaeta, chosen to represent differences in size and a variety of biotopes, was studied electron microscopically after fixation with the acrolein-TAPO-osmium tetroxide method. Five distinct layers in the cuticle of all studied species were found. Staining with lead and uranyl ions or with silver proteinate visualized basically the same structural components of the cuticle, but the degree of electron opacity and the distribution of the electron-opaque stain in these components differed according to the staining method used. Since the acrolein-TAPO-osmium tetroxide method visualized the cuticular zones preferentially stained by Thiéry's silver proteinate method, it was concluded that the TAPO method may be considered suitable for the visualization of polysaccharides. Staining with phosphotungstic acid provided some information on the composition of the cuticle of Oligochaeta not obtained by staining ultrathin sections with lead and uranyl ions nor with silver proteinate. The conclusion is that phosphotungstic acid binds to polysaccharides which do not contain vicglycol groups nor active sites responsible for the positive reaction with lead and uranyl salts. Structural components in the cuticle of the oligochaetes studied were characteristic for each species. The taxonomic value of such components, however, must be confirmed by examination of a larger number of species of oligochaetes.
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  • 166
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Laboratory-reared outgrowths of the freshwater sponge Corvomeyenia carolinensis Harrison were examined using histological and histochemical techniques, supplemented by phase contrast observations of cellular behavior. The tissue and cellular components of the spongillid outgrowth region were defined in terms of function and morphogenic state. Archeocytes differ considderably, in both histochemical and morphological characteristics, from other cell types of the adult sponge, being histochemically similar to stem cells reported from a variety of developmental series. Archeocytes exhibit cytological characteristics of unspecialized cells capable of high levels of synthetic activity while other cell types of C. carolinensis, for the most part, can be characterized as fully differentiated cells displaying more restricted synthetic capabilities but often accumulating neutral mucoproteins. The presence of aggregates of amebocytes, not identifiable as archeocytes and possibly engaged in gemmule formation, is discussed in terms of current concepts of gemmulation and cellular developmental capabilities in sponges.
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  • 167
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    Journal of Morphology 143 (1974), S. 1-1 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 168
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    Journal of Morphology 143 (1974), S. 337-347 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning electron microscopy revealed spores of Nosema apis and Thelohania fibrata to be egg-shaped, but only the mature spore of T. fibrata was shown to possess a horseshoe-like concavity at the posterior pole. Freezeetched preparations indicated that this concavity was due to a thin area of the spore coat. Freeze-etching studies also show spores of N. apis do possess an umbrella-shaped polaroplast, and a polar filament which is arranged in a double layer with over 30 coils. The spore of T. fibrata contains a pear-shaped arrangement of the polaroplast membrane, and a polar filament arranged in a single layer of 22 coils.
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  • 169
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    Journal of Morphology 143 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 170
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    Journal of Morphology 142 (1974), S. 351-363 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gill development begins on the sixth day of incubation at 10°C and is complete by 31 days (hatching). Gill arches are formed by fusion and perforation of ectoderm and endoderm across the pharyngeal wall. A primary branchial artery forms within each arch and a second branchial artery forms as a branch from its ventral end. A series of filament loop vessels forms connecting the two arteries and when several are patent a unidirectional blood flow is established via afferent (second) branchial artery, filament loop vessels to efferent (primary) branchial artery. Part of the efferent branchial artery just above its junction with the afferent branchial artery constricts and occludes. It is suggested that this change in the pattern of blood flow is dependent on differences in resistance of the two branchial arteries. A later extension of the gill ventrally is thought not to be homologous with similar regions in elasmobranchs and Acipenser.
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  • 171
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    Notes: Scanning and transmission electron microscopy studies were conducted on the antennal sensory sensilla of the hymenopteran parasitoid, Cardiochiles nigriceps Viereck, of the family Braconidae. Distinct morphological differences were found between the chemoreceptors of the male and female. Curved, non-fluted, thin-walled sensilla were found to be very abundant on the male and restricted in location and number on the female. Trichoid, placoid and fluted basiconic sensilla were numerous on the antennal flagella of both sexes. Smooth basiconic sensilla were restricted in number to one per flagellar segment in both sexes. Behavioral data suggest that bent-tipped, thick-walled sensilla unique to the female are involved in detecting a chemical(s) emitted from the host, Heliothis virescens (Fab.).
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  • 172
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    Notes: Well preserved transitional cells were found between differentiated cells and horny cells of the frog epidermis, thus facilitating the study of the sequential events involved in horny cell formation. Autolysosomes appear to play an important role in the formation of horny cells. These structures preferentially digest those cytoplasmic components which are not necessary constituents of the terminal horny cell. The release of the contents of the small mucous granules into the intercellular spaces is one of the initial events in horny cell formation. Filaments and large mucous granules seem to be resistant to the lytic digestion and contribute to the bulk of the horny cell. Loss of fluids through the plasma membrane and consolidation of the remaining constituents, results in a flattened horny cell. The appearance of a thickened membrane around the horny cell signifies the completion of the transformation process.
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  • 173
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    Journal of Morphology 142 (1974) 
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  • 174
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: The fiber constituents and connections of the calyces  -  the input-receiving regions  -  of the corpora pedunculata (“mushroom bodies”) were studied in reduced silver preparations from the American cockroach, Periplaneta americana (L.). In the outer synaptic layer of the calyces five fiber classes were distinguished, the first three of which arise outside the mushroom body. (1) Four highly similar neurons with somata near the optic lobe branch into different parts of the ipsiateral protocerebrum, including both calyces. Their fibers are highly constant in arrangement and position and contain small nucleus-like bodies. (2) The tractus olfactorio-globularis (sensu lato) emits fiber groups which course along the calycal walls as “calycal tracts” before ultimately dissipating into the synaptic layer. Variability within these tracts is described. (3) Fibers of undertermined origin outside the mushroom body radiate from the calycal center outwards through the synaptic layer. (4) From the inner calycal layer of neurites belonging to intrinsic mushroom-body neurons, perpendicular collaterals enter the synaptic layer. (5) Intrinsic-neuron somata near the calycal rim emit fibers which course tangentially within the synaptic layer from calycal rim to center. These fibers form a special peripheral zone in the pedunculus.The predominant presumably afferent calycal fiber class is that derived from the tractus olfactorio-globularis. No evidence was found for tracts from optic lobe to calyces. On this basis, and in light of the experimental and comparative anatomical literature, it is suggested that the corpora pedunculata of P. americana and other pterygotes are fundamentally second-order antennal sensory processing centers.Conflicting observations in earlier reports are critically discussed.
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  • 176
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    The @Anatomical Record 178 (1974) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Medicine
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  • 177
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    Topics: Medicine
    Notes: The urinary bladder of the bullfrog, Rana catesbiana has been studied by light and electron microscopy. Three epithelial cell types were found: (1) granular cells, (2) mitochondria-rich cells, and (3) basal cells. The structure of the Rana catesbiana bladder differs from that of the toad Bufo marinus, in several respects: it lacks a mucous (goblet) cell type, its granular cells do not contact the underlying basement membrane, it has specialized, smooth-muscle cell-basal epithelial cell contacts, not previously described in amphibian bladders, and its mucosa is richly innervated. Mitochondria-rich cells within the bullfrog bladder epithelium were occasionally observed touching the basement membrane. The specialized smooth muscle-basal cell contacts provide anatomical evidence for how regulatory vasoactive substances such as neurohypophyseal peptides might alter epithelial geometry. Many nerve endings invest the mucosa just beneath the epithelial basement membrane in proximity to mitochondriarich cells and basal cells. The possible role of neural regulation in epithelial transport was discussed.
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  • 178
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Medicine
    Notes: Postnatal maturation of nonmyelinated fiber bundles (Schwann bundles) was studied in the sciatic nerves of Snell's dwarf mice. The homozygous recessive of this strain has been previously shown to be characterized by multiple pituitary hormone deficiencies and secondary hypothyroidism.In the normal littermates a reduction occurred between 10 and 14 days in the number of fibers per fascicle, or subdivision, of each Schwann bundle, and by 26 days nearly all of the axons were separately embedded in cytoplasmic furrows of their associated Schwann cells. Only a few large fascicles were seen in normal sciatic nerve specimens at 26 and 50-53 days. In contrast, fiber bundle fascicles in the mutant nerves were still represented, even at 50-53 days, by numerous tightly-packed axons, as seen in the immature nerves at 10-12 days post-partum.On the basis of the dwarf's physiological background, these results suggest an involvement of the endocrine system during later stages of peripheral nerve maturation. The possible mechanisms affected by postnatal endocrine deficiency and thereby leading to delayed segregation of nonmyelinated fibers within Schwann bundles are discussed.
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  • 179
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    The @Anatomical Record 178 (1974), S. 139-143 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Hamsters injected at 0900 on day 1 of the cycle (metestrus) with either 0, 5 or 15 IU pregnant mare's serum (PMS) were killed at 1500 of days 1 to 4 of the cycle and the ovaries prepared for light microscopy and for a quantitative evaluation of follicular development. In the untreated cyclic hamster, the maximal number of preantral follicles with eight or more layers of granulosa cells occurred between the afternoon of day 4 (proestrus) and day 1, coinciding with the highest blood levels of FSH and LH. It is concluded that the elevated preovulatory levels of gonadotropins not only induce the ovulation of the mature antral follicles but at the same time recruit the next set of follicles for development during the new cycle.By the afternoon of day 1, treatment with either 5 or 15 IU PMS recruited more follicles into large preantral and incipient antral stages than in the untreated hamsters. However, by day 2 the pattern of follicular distribution was similar between the 5 IU PMS and untreated group whereas considerably more antral follicles had differentiated in the animals given 15 IU PMS. The ability of 15 IU PMS to elicit superovulation therefore depends on the levels being initially high enough to mature more follicles at critical stages of their development; the prolonged biological half life of PMS then sustains these follicles throughout the cycle.
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  • 180
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    The @Anatomical Record 178 (1974), S. 203-209 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: During the postnatal development of the submandibular gland, the stimulation of DNA synthesis and mitosis by a single injection of isoproterenol, measured as the percentage of labeled cells in radioautographs, was dependent on the age of the rat. The drug had no effect on the proliferative activity in two day old rats, but stimulated DNA synthesis in older (7-42 day old) animals. In general, the degree of stimulation was directly related to the proportion of acinar cells and inversely related to the proliferative activity in the gland of control rats. An analysis of various cell types revealed that the stimulation of DNA synthesis in the gland was essentially restricted to the acinar cells in rats older than 14 days of age. In seven day old rats, the acinar cells were not stimulated, but their precursors, the proacinar cells, the terminal tubule cells and the intercalated duct cells were stimulated to synthesize DNA by isoproterenol. This suggested that isoproterenol had an effect on the transformation of precursor cells to acinar cells.
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  • 181
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Keratinization or mucification of the epithelium of the rat vagina is related to the hormonal state of the animal. During the normal cycle and after the administration of exogenous hormones (estrogen and progestin) to spayed animals, the surface characteristics and topography of the vaginal epithelium were studied with the scanning electron microscope. During estrus and under the influence of estrogen, the superficial cells were keratinized, overlap each other like shingles, and are continuously sloughed off. Like the surface of other keratinizing epithelia, theirs has a characteristic microridge pattern. In ovariectomized animals, the apical surface is covered with microvilli instead of microridges, and the cells resemble hexagonally shaped units, tightly bound instead of overlapping each other. At the boundary between the cells, a ridge demarcates the cells. The surface configurations of progestin-treated, progestin plus estrogen-treated, and diestrous animals are the same as in spayed animals.
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  • 182
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    The @Anatomical Record 178 (1974), S. 1-1 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 183
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    The @Anatomical Record 178 (1974), S. 41-48 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This report compares the arterial supply of the lumbo-sacral spinal cord in the monkey with that of man. The arterial supply to the lumbo-sacral cord of 100 monkeys (82 Rhesus and 18 Mangabey) was demonstrated by perfusion techniques. We tabulated the level and side of origin of the great anterior medullary artery. Previous authors have shown that in man the peak incidence of the great anterior medullary artery is at T-10. The peak incidence in the monkey is at L-1. There are other features of the arterial supply to the lumbo-sacral cord of the monkey that are different from man.
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  • 184
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An initial study of the effects of long-term ovariectomy on fimbrial and ampullar epithelia from rabbit oviducts has been made with the scanning electron microscope. Several of the rabbits were given estradiol benzoate before they were killed. These observations were compared with those of epithelial cells from similar oviductal segments from post-ovulatory rabbits that served as controls.Fimbriae from oviducts of control animals were densely ciliated, partially concealing the bulbous processes of the secretory cells. In the ampullae the processes of the secretory cells were the predominant structure, their bulbous apices rising frequently above the tips of the cilia.When rabbits had been spayed for 16-18 months, the epithelial cells of both fimbriae and ampullae showed a remarkable change. A few cilia in small clumps were scattered among the secretory cells. The free surface of the secretory cells had become flattened and hexagonal in shape. Their microvilli were short, and from the center of each cell a thick, stubby central cilium protruded.Estrogen given the long-term spayed rabbits caused almost complete reciliation as well as restoration of the bulbous processes of the secretory cells.
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  • 185
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    The @Anatomical Record 178 (1974), S. 127-137 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The morphogenesis of cerebellum has been studied in 6-19 day old chick embryos after a single injection of 0.05 mg of cyclophosphamide into the yolk sacs on the fifth day of incubation. Besides degeneration of Purkinje cells, rate of development was markedly retarded as evidenced by late appearance of the fissures and folia of the cerebellum. Purkinje cells remained disorganised up to 18 days of incubation, though in controls they were arranged in a single line by the fifteenth day. The thickness of the external granular layer increased and persisted for a longer period in the treated embryos. The cytoarchitecture returned to normal on nineteenth day of incubation, but the size of the cerebellum was significantly smaller than that of controls (P 〈 0.001). Such transient disorganisation of the morphogenetic events in the neural tube may lead to inadequate and defective induction of surrounding mesenchyme, thereby resulting in defective skull formation through which the brain can herniate, i.e., exencephaly as reported in our earlier studies after cyclophosphamide administration in chicks (Singh et al., '71; Singh and Gupta, '72) and rats (Singh et al., '72).
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  • 186
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    The @Anatomical Record 178 (1974), S. 187-201 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The postnatal differentiation of acini in the submandibular glands of 2-42 day old rats given 3H-thymidine was studied by using radioautographs prepared from Epon-embedded, PAS and iron hematoxylin stained sections. The changes in morphology, population size and proliferative activity of various cell types in the gland were analyzed. At two days of age, rudimentary secretory units, designated as terminal tubules, were located at the end of the duct system and consisted of three cell types: (1) terminal tubule cells (30.7%) with darkly-stained granules, (2) proacinar cells (23.6%) with large, lightly-stained granules, and (3) acinar cells (1.6%) with PAS-positive granules. The proacinar cells, which underwent mitosis, disappeared within the first two weeks of life. The terminal tubule cells increased in number between 2 and 14 days of age, but became less numerous thereafter and disappeared by six weeks. Concomitantly, the number of acinar cells increased linearly with age and at a much greater rate than that of intercalated duct cells. Yet the rate of proliferation of acinar cells was comparable to that of intercalated duct cells. The overall proliferative activity in the gland decreased with age, and was inversely correlated with the relative frequency of acinar cells in the gland. On the basis of above data, it is postulated that, during the formation of acini from terminal tubules, acinar cells have a dual origin: they arise from proacinar cells during the first one to two weeks and from terminal tubule cells between two and six weeks of age.
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  • 187
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    The @Anatomical Record 178 (1974), S. 623-630 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: It has often been reported that facial proportions remain constant throughout the fetal period. Such conclusions, however, have been based largely on the erroneous assumption that two dimensions are growing isometrically if one bears a statistically significant linear relation to the the other. In order to test the hypothesis that proportion is independent of time, sagittal histologic sections from 32 human fetuses (12-25 weeks) were analyzed cephalometrically. The linear regression on head length (HL) and the associated coefficient of correlation were calculated for each of a variety of craniofacial measures. In addition, all linear dimensions were transformed so that the size of the anterior cranial base was held constant throughout the series. It was assumed that if shape be constant, all Y-intercepts should be zero, and angular and transformed linear dimensions should show no statistically significant linear correlation with HL. These three criteria were met uniformly by facial and anterior cranial base dimensions, but not by measurements which involved the posterior cranial base. It is concluded, therefore, that in the sagittal plane the second trimester mandible, midface, and anterior cranial base grow isometrically, while the posterior cranial base becomes relatively smaller.
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  • 188
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    The @Anatomical Record 178 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 189
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Light microscopy of semithin sections revealed an increase in blood vessel profiles between one and three weeks postnatal. Ultrastructurally, at birth, there were few patent vessels, but endothelial cells enclosing a slit-like lumen were numerous. The endothelial cells contained a high concentration of free ribosomes and pinocytotic vesicles. Pseudopod projections of the endothelial cells into the vascular lumen were often present. The nuclei were very irregular and dense with clumped chromatin. The basal lamina varied in thickness. During the period between one and three weeks the nuclei of endothelial cells became less dense; the lumen became patent and the endothelial wall progressively thinner. The periphery of the vessel became completely surrounded by glial end feet and the basal lamina was regular and prominent. By three weeks, most blood vessels resembled blood vessels observed in a mature animal. Pericytes were present at all stages of development. The extracellular space which was quite conspicuous at birth was greatly reduced by the third week.
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  • 190
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Light microscopic studies using a battery of basic dye stains combined with sialidase and hyaluronidase digestions indicated that the extensive basophilia of the maternal surface of the placental syncytium largely results from the presence of a non-sulfated mucosubstance specifically identified as hyaluronic acid. Ultrastructural examination of dialyzed iron (DI) stained specimens revealed that DI-positive filaments observed along the syncytial surface were removed by hyaluronidase digestion. Staining with the lectins, Concanavalin A or lentil bean hemagglutinin produced an intense and periodic pattern of staining that was not enzyme labile. Incubation of tissue sections in the enzyme solutions or control buffers allowed the lectins to penetrate the syncytial plasma membrane and stain material within the endoplasmic reticulum presumed to be human chorionic gonadotropin. The maternal surface exhibited essentially no reactivity for acid phosphatase but showed strong alkaline phosphatase activity with a periodic staining pattern. With each of the techniques used there was variability in the intensity of staining in different regions along the maternal surface, suggesting that functionally different zones may be identified cytochemically. Only minor differences were observed in the cytochemical reactivity of early compared with term placenta.
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  • 191
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Evidence for a direct neural projection from the retina to the hypothalamus in the golden hamster (Mesocricetus auratus) is presented. In 25 blinded animals degeneration was followed in sections prepared according to the Wiitanen ('69) silver impregnation method. Degenerative axons were found in the optic tract, chiasm, and nerve, terminating in the lateral geniculate body and superior colliculus. A large collateral bundle of degenerating axons was observed curving medially and dorsally to enter the hypothalamus at the level of the mamillary body. This bundle turned diffusely rostrally and terminated on neurons in the ventromedial nucleus of the hypothalamus.It is proposed that two alternate pathways exist for the effect of photoperiodicity on the reproductive cycle in the hamster, one involving the pineal gland directly and the hypothalamus indirectly, and the other a direct retino-hypothalamic projection.
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  • 192
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 179 (1974) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 193
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 179 (1974), S. 147-161 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The organization of the sensory innervation of Golgi tendon organs (GTO) from E. carpi ulnaris of the cat is described. The large Ib afferent fiber gives rise to small myelinated branches which become oriented longitudinally in a neural compartment of the GTO capsule lumen. The latter give rise to smaller, unmyelinated branches which further arborize among loosely packed collagen bundles. The unmyelinated fibers form numerous varicosities and small terminal branches which have portions of the axolemma covered only by basal lamina which intervenes between the collagen bundles and the axolemma. In places, the axon's surface may lack all investments and nerve and collagen come into intimate association. The large unmyelinated branches and their varicosities have different axoplasmic characteristics compared with the small unmyelinated terminal portions. The latter contain few or no mitochondria, vesicles, neurotubules, and neurofilaments. In addition to the description of the terminals, the similarities and differences of the innervation of the GTO, compared with other mechanoreceptors, are discussed.
    Additional Material: 1 Ill.
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  • 194
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The vaginal epithelium of the normal estrous mouse shows narrow intercellular spaces, many cytoplasmic fibrils and a continuous basal lamina. At 100 days of age, the vaginal epithelium of mice which had received 5 or 20 μg estradiol-17β, 20 μg ovine prolactin, or 5 μg estradiol-17β + 20 μg prolactin within the first few days of postnatal life, shows wider intercellular spaces in the middle epithelial layers than occur in normal estrous mice. In addition, the mice receiving 20 μg estradiol-17β show prominent intercellular spaces in the basal cell layer and interruptions in the basal lamina, which permit penetration of cytoplasmic processes into the subjacent connective tissue. The relevance of these findings to vaginal carcinogenesis is considered.
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  • 195
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 179 (1974) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 196
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A study of the uptake of exogenous proteins, peroxidase, ferritin, and myoglobin by rabbit blastomeres of different developmental stages was undertaken to determine some of the means by which these stages ingest protein. Exposure of embryos in preimplantation stages, ranging from fertilized ovum to late blastocyst, was carried out in vitro with selected in vivo controls. Blastomeres of early cleavage stages up to the morula show little uptake of peroxidase. However, the endocytosis of peroxidase greatly increases with the morula stages and continues at an elevated level through the blastocyst stages. The uptake of the tracer is initially accomplished via micropinocytotic vesicles and tubules and can have several subsequent fates. The tracer can pass into larger vacuoles and be transported into the cavity of the blastocyst, or can pass into multivesicular bodies where it is presumably degraded by the lysosomal system for cellular use. The use of myoglobin at selected blastocyst stages yielded results similar to those obtained with peroxidase. However, the response by the blastomeres to ferritin is different. Endocytosis of ferritin is scant at all preimplantation stages, even though the ferritin has no difficulty reaching the surface of the blastomeres. The experiment with mechanically denuded blastocysts indicated that ferritin did not adsorb to the cell surface.
    Additional Material: 1 Tab.
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  • 197
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 198
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974), S. 281-283 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Using bipolar fine-wire electrodes, we investigated the function of the pectineus muscle. Electromyography revealed that the main function of pectineus muscle is flexion, adduction and medial (not lateral) rotation of the hip joint. These functions suggest that the spasm of this muscle may be important in the cause of deformities in cerebral palsy.
    Additional Material: 1 Ill.
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  • 199
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Guinea pig visceral yolk sac endoderm cells are known to absorb proteins from the uterine lumen by the process of pinocytosis. Since previous studies have shown that the first step in protein absorption is the binding of the protein to an extracellular material on the surface of pinocytotic invaginations, it was thought that the surface coat might possess receptor sites for molecules which are subsequently absorbed. This study investigates the nature of the surface coat of the endoderm cells using ruthenium red, alcian blue/cetylpyridynium chloride-lanthanum and concanavalin A-peroxidase procedures. Results using these methods showed the presence of a surface coat on both the microvilli and pinocytotic invaginations. The coat on the pinocytotic invaginations was thicker than that on the microvilli. Concanavalin A receptor sites were separated from one another on the cell surface. Since only those pinocytotic invaginations which were open to the surface at the time of fixation would be “stained” by these methods, the procedures also show that the numerous tubules and vesicles in the apical cytoplasm do not all form an intercommunicating labyrinth open to the surface, even though most of them are part of a related functional system. The results indicate that the surface coat contains mucopolysaccharide components. In addition, concanavalin A receptor sites are present which are probably oligosaccharides associated with a glycoprotein component of the apical cell membrane.
    Additional Material: 8 Ill.
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  • 200
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974), S. 331-339 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The microscopic anatomy of the accessory glands of black-tailed prairie dogs (Cynomys ludovicianus) and thirteen-lined ground squirrels (Citellus tridecemlineatus) have been studied. In addition, the glands of a 5 cm fetal prairie dog have been described. Adult and fetal prairie dogs and adult ground squirrels have so-called seminal vesicles folded dorsally over the dorsal prostate with ducts leading directly to the urethra lateral to, but in the region of, the entrance of both the dorsal prostatic ducts and the deferent ducts. Histological studies of the seminal vesicles of both prairie dogs and ground squirrels showed that they were tubuloalveolar glands and were similar in structure to the dorsal prostates of each species. The fructose concentrations of the dorsal prostate and seminal vesicles of out-of-season prairie dogs were similar, and both glands accumulated fructose with the onset of the breeding season or with injection of testosterone propionate but the seminal vesicles accumulated more fructose than the prostate. On the basis of histological structure, anatomical relationships, accumulation of fructose and possible function as a coagulating gland it is proposed that the proper name for the so-called seminal vesicles in these species is craniodorsal prostate.
    Additional Material: 6 Ill.
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