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  • Artikel  (61)
  • CR: 5.17  (24)
  • Protein synthesis  (20)
  • Chromatographie, Gas  (17)
  • Springer  (61)
  • 1980-1984  (61)
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  • 1980  (61)
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  • Springer  (61)
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  • 1980-1984  (61)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Computing 25 (1980), S. 317-335 
    ISSN: 1436-5057
    Schlagwort(e): AMS (MOS): 65L65 ; CR: 5.17 ; AMS (MOS): 65L65 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Beschreibung / Inhaltsverzeichnis: Abstract In this paper a general procedure to obtain spline approximations for the solutions of initial value problems for ordinary differential equations is presented. Several well-known spline approximation methods are included as special cases. It is common practice to partition the interval for which the initial value problem is defined into equidistant subintervals and to construct successively the spline approximation; thereby the spline function has to satisfy certain conditions at the knots. In the general procedure presented here additional knots are admitted in every subinterval. At these points which need not be equally spaced the spline approximation has to fulfill analogous conditions as at the original knots. Convergence and divergence theorems are proved; especially the influence of the additional knots on convergence and divergence of the method is investigated.
    Notizen: Zusammenfassung In dieser Arbeit wird ein allgemeines Verfahren zur Erzeugung von Splineapproximationen für die Lösungen von Anfangswertproblemen bei gewöhnlichen Differentialgleichungen vorgestellt. Einige der bekannten Spline-approximationsmethoden sind als Spezialfälle enthalten. Eine gängige Vorgehensweise besteht darin, das Intervall, über dem das Anfangswertproblem gegeben ist, in äquidistante Teilintervalle zu zerlegen und dann sukzessive die Splineapproximation zu definieren. Hierbei wird gefordert, daß die Spline-approximation in den Knoten gewisse Bedingungen erfüllt. Bei dem hier betrachteten allgemeinen Verfahren werden in den einzelnen Teilintervallen noch zusätzliche Zwischenknoten eingeführt. In diesen Punkten, die nicht äquidistant sein müssen, werden für die Splineapproximation analoge Bedingungen wie in den Hauptknoten vorgeschrieben. Konvergenz- und Divergenzsätze werden bewiesen, insbesondere wird der Einfluß der Zwischenknoten auf Konvergenz und Divergenz des Verfahrens untersucht.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 2 (1980), S. 61-67 
    ISSN: 1432-0983
    Schlagwort(e): Axenomycin ; Ribosome genetics ; Yeast ; Protein synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Axenomycin inhibits protein synthesis in vivo and in vitro in Saccharomyces cerevisiae. The antibiotic acts by binding to ribosomes, most probably to the large ribosomal subunit. Mutant strains resistant to axenomycin appear to contain ribosomes that are not inhibited by the antibiotic. The responsible gene has been mapped on the VII chromosome between the centromere and the leu1 gene.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 15 (1980), S. 339-345 
    ISSN: 1432-1432
    Schlagwort(e): Protein synthesis ; Origin ; Activation ; Initiation ; pKa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The data presented in this paper show that the ease of non-enzymatic activation of carboxylic acids by ATP at pH 5 varies directly with the pKa of the carboxyl group, and is consistent with the idea that it is the protonated form of the carboxyl group which participates in the activation reaction. Consequently, since most N-blocked amino acids have higher pKa's than do their unblocked forms, they are activated more readily, and we have demonstrated that this principle applies to peptides as well,which are activated more rapidly than single amino acids. We propose that this fact may be partly responsible for the origin of two important features still observed in contemporary protein synthesis: (1) initiation in prokaryotes is accomplished with an N-blocked amino acid, and (2) elongation in all living systems occurs at the carboxyl end of the growing peptide.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 235-246 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65L05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary A class of extended backward differentiation formulae suitable for the approximate numerical integration of stiff systems of first order ordinary differential equations is derived. An algorithm is described whereby the required solution is predicted using a conventional backward differentiation scheme and then corrected using an extended backward differentiation scheme of higher order. This approach allows us to developL-stable schemes of order up to 4 andL(α)-stable schemes of order up to 9. An algorithm based on the integration formulae derived in this paper is illustrated by some numerical examples and it is shown that it is often superior to certain existing algorithms.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 127-142 
    ISSN: 0945-3245
    Schlagwort(e): AMS (MOS): 34G05, 65L05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary A class of approximation schemes of arbitrary accuracy, generated by a two-step recurrence relation, is devised for evolution equations of the second order. The schemes are effected via a specially constructed family of rational approximations to cos τ for τ≧0 and yield computationally efficient methods for systems of second-order ordinary differential equations and semidiscrete approximations for initial-boundary value problems for second-order hyperbolic equations.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 143-162 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65M15, 65N30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary We study the error due to the discretization in time of a nonlinear parabolic problem by a multistep method. Error estimates are obtained if the method is of the orderp (p〉1) and stronglyA(Θ)-stable $$\left( {0〈 \Theta〈 \frac{\pi }{2}} \right)$$ . The method is also applied to the Navier-Stokes equations in two dimensions.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 231-240 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65L10 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary The homotopy method is a frequently used technique in overcoming the local convergence nature of multiple shooting. In this paper sufficient conditions are given that guarantee the homotopy process to be feasible. The results are applicable to a class of two-point boundary value problems. Finally, the numerical solution of two practical problems arising in physiology is described.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 257-276 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS) ; 65M10 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Beschreibung / Inhaltsverzeichnis: Résumé Considérons une équation d'évolution parabolique linéaire associée à un opérateur linéaireA(t) dépendant du tempst. Nous développons dans cet article une méthode de discrétisation, basée sur les méthodes linéaires à pas multiples, traitant de manière implicite une partie de l'opérateurA(t) indépendante du temps, l'autre partie est traitée de manière explicite. Nous étudions la stabilité et la convergence de cette méthode.
    Notizen: Summary Let us consider a linear parabolic equation which is associated with a time dependent operatorA(t). In this paper, we present a method, which is founded on linear multistep methods, which discretize a time-independent part of the operatorA(t) in an implicit way, and the other part in an explicit way. We study stability and convergence for this method.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 315-341 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS) ; 65N30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary We present here some new families of non conforming finite elements in ℝ3. These two families of finite elements, built on tetrahedrons or on cubes are respectively conforming in the spacesH(curl) andH(div). We give some applications of these elements for the approximation of Maxwell's equations and equations of elasticity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 381-404 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65N30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary We study in this paper the convergence of a new mixed finite element approximation of the Navier-Stokes equations. This approximation uses low order Lagrange elements, leads to optimal order of convergence for the velocity and the pressure, and induces an efficient numerical algorithm for the solution of this problem.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 189 (1980), S. 215-219 
    ISSN: 1432-041X
    Schlagwort(e): Mouse eggs ; Microsurgical enucleation ; Maternal mRNA ; Protein synthesis ; 2-Dimensional polyacrylamide gel electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Fertilized and unfertilized C57BL/6J eggs were microsurgically enucleated and then analyzed for their capacity to synthesize proteins using 2-dimensional polyacrylamide gel electrophoresis. In both types of enucleated eggs (cytoplasts), protein synthesis continued and was still detected up to three days in culture. Shortly after enucleation, the pattern of polypeptides remained similar to the respective non-operated control eggs but it later became gradually reduced in intensity and complexity. After two days of culture the appearance of some new proteins typical for 2-cell embryos was observed in enucleated fertilized eggs only. Our findings suggest that maternal mRNA stored during oogenesis is utilized during the preimplantation period.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 171-187 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65N05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary Difference methods for the numerical solution of linear partial differential equations may often be improved by using a weighted right hand side instead of the original right hand side of the differential equation. Difference formulas, for which that is possible, are called “Mehrstellenformeln’ or Hermitian formulas. In this paper the Hermitian formulas for the approximation of Laplace's operator are characterized by a very simple condition. We prove, that in two-dimensional case for a Hermitian formula of ordern at leastn+3 discretization points are necessary. We give examples of such optimal formulas of arbitrary high-order.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 457-467 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65L05, 65Q05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary By employing a numerical method which uses only rather classical tools of Numerical Analysis such as Newton's method and routines for ordinary differential equations, unstable periodic solutions of differential-difference equations can be computed. The method is applied to determine bifurcation diagrams with backward bifurcation.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 13-20 
    ISSN: 0945-3245
    Schlagwort(e): AMS (MOS): primary 65M05 ; 65M10 ; 65M15 ; secondary: 35M05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary We consider the numerical solution of the Tricomi problem. Using a weak formulation based on different spaces of test and trial functions, we construct a new Galerkin procedure for the Tricomi problem. Existence, uniqueness, and uniform stability of the approximate solution is proven, and a priori error bounds are given.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 21-33 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65B05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary The trapezoidal rule with deferred corrections using uncentered end formulas is shown to converge. While the proof technique is more specialized than the standard asymptotic expansion approach, it has some advantages. In addition to providing a more complete theoretical justification for current implementations of deferred corrections with the trapezoidal rule, the approach given here will hopefully apply for several other discretization methods.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 35 (1980), S. 57-68 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65L05 ; 65M20 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary This paper discussesrational Runge-Kutta methods for stiff differential equations of high dimensions. These methods are explicit and in addition do not require the computation or storage of the Jacobian. A stability analysis (based onn-dimensional linear equations) is given. A second orderA 0-stable method with embedded error control is constructed and numerical results of stiff problems originating from linear and nonlinear parabolic equations are presented.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 36 (1980), S. 253-266 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65LO5 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary Single step exponentially fitted integration formulae of orders 4 and 6 are derived. The final approximation to the required solution is obtained via a linear combination of asymptotically less accurate solutions obtained using conventional implicit integration formulae. This linear combination is performed in such a way that the final integration formula, as well as having an increased order of accuracy, integrates a certain pre-determined ordinary differential equation exactly. The algorithms developed are illustrated by means of some numerical examples.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 29-40 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65N25 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary A method is constructed which yields a strip containing the full solution sets of nonlinear eigenvalue problems of the formu=λTu. The strip can be narrowed iteratively, and the method applies for both stable and unstable branches. Its high degree of accuracy is demonstrated by numerical examples. In particular, a lower bound is given for the critical value at which criticality is lost in the thermal ignition problem for the unit ball.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 41-62 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65N30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract This paper presents a new approach to the analysis of finite element methods based onC 0-finite elements for the approximate solution of 2nd order boundary value problems in which error estimates are derived directly in terms of two mesh dependent norms that are closely ralated to theL 2 norm and to the 2nd order Sobolev norm, respectively, and in which there is no assumption of quasi-uniformity on the mesh family. This is in contrast to the usual analysis in which error estimates are first derived in the 1st order Sobolev norm and subsequently are derived in theL 2 norm and in the 2nd order Sobolev norm — the 2nd order Sobolev norm estimates being obtained under the assumption that the functions in the underlying approximating subspaces lie in the 2nd order Sobolev space and that the mesh family is quasi-uniform.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 143-154 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65L65 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary In the first part [1] a general procedure is presented to obtain polynomial spline approximations for the solutions of initial value problems for ordinary differential equations; furthermore a divergence theorem is proved there. Sufficient conditions for convergence of the method are given in the second part [2]. The remaining case which has not been considered in [1] and [2] is treated in the present paper. In this special case the procedure is equivalent to an unstable two-step method with special initial values; nevertheless, convergence can be proved. Finally,A 0-stability of the method as well as the influence of rounding errors are investigated.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 34 (1980), S. 1-13 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 34A45, 34A50, 65L05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary In this paper Lie series are presented in Chebyshev form and applied to the iterative solution of initial value problems in differential equations. The resulting method, though algebraically complicated, is of theoretical interest as a generalisation of Taylor series methods and iterative Chebyshev methods. The theory of the method is discussed and the solutions of some simple scalar equations are analysed to illustrate the behaviour of the process.
    Materialart: Digitale Medien
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  • 22
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65M25, 35L20 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary The ALGOL-procedure1 char2 presented in this paper can be applied to the initial or initial-boundary value problem of a quasilinear hyperbolic differential equation of second order. A method of characteristics is combined with extrapolation to the limit. Thus, the results are very accurate. The same accuracy can also be obtained if the initial values are only piecewise smooth.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 36 (1980), S. 1-25 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65 N 30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary We begin in this paper the study of a general method of approximation of solutions of nonlinear equations in a Banach space. We prove here an abstract result concerning the approximation of branches of nonsingular solutions. The general theory is then applied to the study of the convergence of two mixed finite element methods for the Navier-Stokes and the von Kármán equations.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 36 (1980), S. 33-52 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65N30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary A modified variational formulation, recently introduced by Taylor, Beresford and Wilson for solving second order problems, using the nonconforming Wilson element is here analysed. It is shown that the Patch Test is satisfied and that stresses and displacements are respectively first and second order accurate for arbitrary quadrilateral meshes.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 36 (1980), S. 73-98 
    ISSN: 0945-3245
    Schlagwort(e): AMS: 35R35, 65P05, 76S05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary A new numerical method is used to solve stationary free boundary problems for fluid flow through porous media. The method also applies to inhomogeneous media, and to cases with a partial unsaturated flow.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 36 (1980), S. 267-290 
    ISSN: 0945-3245
    Schlagwort(e): AMS(MOS): 65N30 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary In this paper, we present a finite element lumped mass scheme for eigenvalue problems of circular arch structures, and give error estimates for the approximation. They assert that approximate eigenvalues and eigenfuctions converge to the exact ones. Some numerical examples are also given to illustrate our results.
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Numerische Mathematik 36 (1980), S. 319-331 
    ISSN: 0945-3245
    Schlagwort(e): AMS (MOS) ; 65L05 ; CR: 5.17
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Summary Burrage and Butcher [1, 2] and Crouzeix [4] introduced for Runge-Kutta methods the concepts ofB-stability,BN-stability and algebraic stability. In this paper we prove that for any irreducible Runge-Kutta method these three stability concepts are equivalent.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Planta 148 (1980), S. 429-436 
    ISSN: 1432-2048
    Schlagwort(e): Auxin action ; Avena ; Coleoptile ; Protein synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Synthesis of growth-limiting proteins (GLP) is required for continued auxin-induced elongation of oat (Avena sativa L.) coleoptiles. In order to determine whether GLP synthesis is dependent or independent of auxin, a double-labeling ratio technique, coupled with disc-gel electrophoresis, has been used to assess the effect of auxin on the pattern of protein synthesis. Sections were peeled to enhance amino-acid uptake; proteins were labeled with [14C]- or [3H] leucine in the presence or absence of indole-3-acetic acid for 40 min to 6 h, and were separated into soluble, membrane-associated, and wall-associated fractions. Regardless of the conditions used, or the protein fraction examined, no changes in response to auxin were detected in the pattern of protein synthesis. In order to escape detection by this technique an auxin-induced protein would have to comprise less than 0.75% of the total newly synthesized protein. Thus the synthesis of GLP appears to be independent of auxin. The same technique has been used to follow protein turnover. During the chase, proteins are initially degraded at an average rate of 8% h−1, and some protein bands showed as much as 14% h−1 degradation. No protein was detected which had a turnover rate as rapid as the GLP.
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  • 29
    ISSN: 1432-2048
    Schlagwort(e): mRNA ; Protein synthesis ; Protoplasts ; Nicotiana ; Translation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Studies of proteins synthesized in vitro by messenger RNA (mRNA) extracted from tobacco protoplasts showed that the changes in protein synthesis and especially the lack of certain proteins observed previously in isolated protoplasts did not result from a failure of translation.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Planta 148 (1980), S. 491-497 
    ISSN: 1432-2048
    Schlagwort(e): Leaves (polysomes) ; Nicotiana ; Polysomes ; Poly(A)+ RNA ; Protein synthesis ; RNA (polysomal, polyA+)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The isolation of intact polysomes from leaves of tobacco (Nicotiana tabacum L.) is dependent on the age and state of development of leaves. Undegraded polysomes from young leaves in the early stages of expansion can be isolated easily by extracting the leaves in ice-cold extraction buffer (200 mM tris(hydroxymethyl)aminomethylmethane(Tris)-HCl, pH 9.0; 400 mM KCl; 200 mM sucrose; 35 mM MgCl2). Medium-size leaves give best yields of undegraded polysomes when extractions are carried out in the above buffer and in the presence of ethyleneglycol-bis-(β-amino-ethyl ether)-N,N′-tetracetic acid (EGTA) and mercaptoethanol. Isolation of polysomes from large, nearly fully expanded (mature) leaves requires all of the above plus diethyldithiocarbamate (DIECA) in the extraction medium. An extraction medium consisting of 25 mM EGTA, 0.01 M mercaptoethanol, 25 mM DIECA and 0.5% of the nonionic detergent, Nonidet-P40 (NP 40) was found to be very suitable for extraction of polysomes from all developmental stages of leaves. The polysomes extracted in the above medium showed active translation of protein in the wheat-germ in-vitro protein-synthesizing system. The translational products were similar when translations were carried out directly with polysomes or polysomal RNA, or polysomal poly(A)+ RNA from tobacco leaves. Poly(A)− polysomal RNA was a poor template in the in-vitro wheat-germ system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Planta 149 (1980), S. 262-268 
    ISSN: 1432-2048
    Schlagwort(e): Hordeum ; Polyribosomes ; Protein synthesis ; RNA ; Seeds ; Storage proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Membrane-bound polysomes were isolated from developing endosperms of barley (Hordeum vulgare L.) and shown to support the synthesis of trichloroacetic acid-insoluble material by an in vitro wheat germ protein synthesis system. The mRNA associated with the polysomes was separated from the ribosomes by affinity chromatography on oligo-dT cellulose and was also shown to support in vitro protein synthesis. The poly-A+ RNA isolated contained material of between 0.55 and 2.55 kilobases in length with about 6% poly A. The products of in vitro protein synthesis resembled hordeins (the prolamin storage proteins of the barley endosperm) in that they were predominantly soluble in 55% propan-2-ol, contained a low proportion of lysine as compared with leucine and had similar, but not identical, electrophoretic properties. The differences in the electrophoretic behaviour between the products of poly-A+ RNA translation and authentic hordeins is suggested to be due to the presence of an extra (leader?) sequence on the former.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Planta 147 (1980), S. 307-311 
    ISSN: 1432-2048
    Schlagwort(e): Embryo ; Protein synthesis ; Scutellum ; Secale ; Translation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Some botanical aspects of cell-free protein synthesizing systems from cereal embryos have been investigated. The composition of the starting material determines both the stability and translation fidelity of the cell-free extracts. The active components of the extracts originate exclusively from the primary axes. Contamination with scutellum fragments does not affect the initial activity but results in a reduced stability. The presence of endosperm particles in the starting material leads to a strong decrease of the overall activity of the extracts and a loss of the capacity to synthesize large polypeptides.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    ISSN: 1432-2048
    Schlagwort(e): Pisum ; Polyribosomes ; Post translational modifications ; Protein synthesis ; Storage proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Polypeptide material has been immunoprecipitated by antivicilin antibodies from translation products of polyribosomes and poly(A)-rich RNA isolated from developing seeds of Pisum sativum in the wheat germ and reticulocyte lysate cell-free synthesis systems. Analysis of this material by SDS-PAGE shows it to consist of three bands, of molecular weights 70,000, 50,000 and 47,000. The in vitro vicilin polypeptides of 70,000 and 50,000 mol. wt. have been shown to be very similar to the 70,000 and 50,000 mol. wt. subunits of vicilin by specific immunoprecipitation, and behaviour on treatment with cyanogen bromide and trypsin. The 50,000 mol. wt. in vitro vicilin polypeptide contains no significant extra sequence compared to the 50,000 mol. wt. vicilin subunit. The 47,000 mol. wt. in vitro vicilin polypeptide has no corresponding subunit in vicilin from mature seeds, but a 47,000 mol. wt. subunit is present in vicilin isolated from developing seeds. Comparison of translation products from polysomes isolated from seeds at middle and late stages of development shows that synthesis of the 50,000 and 47,000 mol. wt., but not 70,000 mol. wt. polypeptides is very much reduced at late stages of development. These results are discussed with reference to the nature of the vicilin fraction.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Planta 148 (1980), S. 491-497 
    ISSN: 1432-2048
    Schlagwort(e): Leaves (polysomes) ; Nicotiana ; Polysomes ; Poly(A)+ RNA ; Protein synthesis ; RNA (polysomal, polyA+)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The isolation of intact polysomes from leaves of tobacco (Nicotiana tabacum L.) is dependent on the age and state of development of leaves. Undegraded polysomes from young leaves in the early stages of expansion can be isolated easily by extracting the leaves in ice-cold extraction buffer (200 mM tris(hydroxymethyl)aminomethylmethane(Tris)-HCl, pH 9.0; 400 mM KCl; 200 mM sucrose; 35 mM MgCl2). Medium-size leaves give best yields of undegraded polysomes when extractions are carried out in the above buffer and in the presence of ethyleneglycol-bis-(β-amino-ethyl ether)-N,N′-tetracetic acid (EGTA) and mercaptoethanol. Isolation of polysomes from large, nearly fully expanded (mature) leaves requires all of the above plus diethyldithiocarbamate (DIECA) in the extraction medium. An extraction medium consisting of 25 mM EGTA, 0.01 M mercaptoethanol, 25 mM DIECA and 0.5% of the nonionic detergent, Nonidet-P40 (NP 40) was found to be very suitable for extraction of polysomes from all developmental stages of leaves. The polysomes extracted in the above medium showed active translation of protein in the wheat-germ in-vitro protein-synthesizing system. The translational products were similar when translations were carried out directly with polysomes or polysomal RNA, or polysomal poly(A)+ RNA from tobacco leaves. Poly(A)− polysomal RNA was a poor template in the in-vitro wheat-germ system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    ISSN: 1432-2048
    Schlagwort(e): Embryo (germination) ; Germination (embryos) ; Protein synthesis ; RNA ; Triticum ; Vigour
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A study has been made of the RNA and protein synthesising systems of wheat embryos isolated from seed lots having high viability but differing in vigour. The rate of RNA and protein synthesis in wheat embryos during the early hours of germination is related to the vigour of the seed lot. The imposition of a stress factor, in the nature of a sub-optimal germination temperature, during germination of isolated wheat embryos magnifies the differences in rates of protein and RNA synthesis between high and low vigour seed. Using cell-free protein synthesising systems it has been demonstrated that an important difference between high and low vigour embryos lies in the relative levels of messenger RNA in the embryo. High vigour embryos contain relatively higher levels of poly A+-RNA (i.e. potential mRNA species) than lower vigour embryos and furthermore the level of poly A+-RNA in high vigour embryos increases during early germination whilst in lower vigour embryos the level decreases. The difference in poly A+-RNA levels accounts, at least partially, for the differences in rates of protein synthesis observed between embryos from high and low vigour wheat seed during early germination at both optimal and sub-optimal germination temperatures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    ISSN: 1432-2048
    Schlagwort(e): mRNA ; Nicotiana ; Protein synthesis ; Ribulose-1,5-bisphosphate carboxylase ; RNA (messenger) ; Translation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The products synthesized in vitro by messenger RNA (mRNA) extracted from Nicotiana sylvestris were analyzed by electrophoresis on polyacrylamide slab gels. Only three of the major polypeptides synthesized are considered here: P55, P32, and P20. P55 and P32 were translated from chloroplast mRNA. P55 corresponds to the large subunit of ribulose-1,5-bisphosphate (RuP2) carboxylase; P32 is probably a chloroplast membrane protein. P20, the polypeptide synthesized from cytoplasmic poly(A)+ RNA, is the precursor of the small subunit of RuP2 carboxylase. The balance between P20 and P32, in which their relative proportions varied inversely, was regulated by the age of the leaves and the time of illumination; we took advantage of this phenomenon to isolate the mRNA from the small subunit in relatively large amounts. This mRNA has a molecular weight of 350,000.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Planta 147 (1980), S. 302-306 
    ISSN: 1432-2048
    Schlagwort(e): mRNA ; Protein synthesis ; Pisum ; Seeds (translation) ; Translation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Extracts from the primary axes of dry pea (Pisum sativum L.) seeds are able to perform an initiation-dependent translation of exogenous mRNA. SDS polyacrylamide gel electrophoresis of the products synthesized under direction of alfalfa mosaic virus RNA (AMV-RNA) and tobacco mosaic virus RNA (TMV-RNA) shows that the fidelity of translation in this pea system is at least as high as in a wheat embryo cell-free protein synthesizing system. The endogenous messengers are also efficiently translated in extracts from the primary axes of pea seeds. The direct translation of these messengers in a homologous cell-free system may be of interest for a study of the products coded for by the long-lived messengers present in this plant.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Planta 148 (1980), S. 429-436 
    ISSN: 1432-2048
    Schlagwort(e): Auxin action ; Avena ; Coleoptile ; Protein synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Synthesis of growth-limiting proteins (GLP) is required for continued auxin-induced elongation of oat (Avena sativa L.) coleoptiles. In order to determine whether GLP synthesis is dependent or independent of auxin, a double-labeling ratio technique, coupled with disc-gel electrophoresis, has been used to assess the effect of auxin on the pattern of protein synthesis. Sections were peeled to enhance amino-acid uptake; proteins were labeled with [14C]- or [3H] leucine in the presence or absence of indole-3-acetic acid for 40 min to 6 h, and were separated into soluble, membrane-associated, and wall-associated fractions. Regardless of the conditions used, or the protein fraction examined, no changes in response to auxin were detected in the pattern of protein synthesis. In order to escape detection by this technique an auxin-induced protein would have to comprise less than 0.75% of the total newly synthesized protein. Thus the synthesis of GLP appears to be independent of auxin. The same technique has been used to follow protein turnover. During the chase, proteins are initially degraded at an average rate of 8% h−1, and some protein bands showed as much as 14% h−1 degradation. No protein was detected which had a turnover rate as rapid as the GLP.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    ISSN: 1432-2048
    Schlagwort(e): mRNA ; Protein synthesis ; Protoplasts ; Nicotiana ; Translation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Studies of proteins synthesized in vitro by messenger RNA (mRNA) extracted from tobacco protoplasts showed that the changes in protein synthesis and especially the lack of certain proteins observed previously in isolated protoplasts did not result from a failure of translation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 108-109 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Ethosuximid, Valproat in Blutserum ; Chromatographie, Gas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Conclusion The proposed simultaneous determination of ethosuximide and valproate takes advantage of the similar properties of these substances that differ markedly from the other mainly used antiepileptic drugs. The volatility as well as the high blood concentration that are usual in therapeutics allow the measurement of ethosuximide and valproate directly in the extract without further concentration, e.g. by evaporation. On the other hand, one can optimise the methods for the determination of the other anticonvulsant drugs that are poorly volatile putting ethosuximide and valproate aside [1] and give up procedures using temperature programs with temperature differences of more than 100 ° C between the starting and the endpoint.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 207 (1980), S. 21-29 
    ISSN: 1432-0878
    Schlagwort(e): Human heart ; Cardiac ultrastructure ; Sarcomerogenesis ; Protein synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The origin of cardiac myofibrils in cells from the atrial wall in human embryos was studied. Z-band substance appears throughout the cytoplasm as irregular electron dense patches in a network of thin filaments. The thin and thick filaments are synthesized as separate units in the sarcoplasm and are later aggregated into myofibrils. Complexes of Z substance and thin filaments occur numerously at different stages of myofibrillar organisation. Thick filaments are formed in close proximity to free ribosomes and are later incorporated in an hexagonal pattern into the Z-band/thin filament complex.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 103 (1980), S. 189-200 
    ISSN: 1615-6102
    Schlagwort(e): ATP content ; ATP turnover ; DMSO ; Protein synthesis ; Tetrahymena
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The content of ATP in cells exposed for 1 hour to 2.5% and 7.5% dimethyl sulphoxide (DMSO) was 90% and about 80%, respectively, of that in control cells. This difference of about 10% in the ATP content cannot explain the previously reported cessation of food vacuole formation in 7.5% DMSO and the uninhibited function in 2.5% DMSO (Nilsson 1974). However, DMSO had a dose-dependent effect on the rate of turnover of ATP in cell extracts, thus the amount of ATP expended per unit time in 7.5% DMSO is only 60% of that expended by extracts of control cells. The rate of protein synthesis was studied by electron microscope autoradiography which revealed considerably less labelled material in DMSO-treated cells than in control cells. Semi-quantitative estimates showed that cells in 2.5%, 5%, and 7.5% DMSO had a rate of incorporation of the labelled amino acid corresponding to 38%, 31%, and 51%, respectively, of that of control cells; the seemingly high rate of incorporation in 7.5% DMSO may reflect a low internal pool of amino acids in these cells. An additional fine structural detail is the induction of intranuclear fibrous bundles in all concentrations of DMSO. The findings are in accord with a random interference of DMSO, presumably by inducing conformational changes in some macromolecules which affect their cellular function.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 5 (1980), S. 67-70 
    ISSN: 1573-5133
    Schlagwort(e): Protein synthesis ; Physiology ; Temperature ; Primary production ; Reproduction ; Body weight ; Fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis Black crappie (Pomoxis nigromaculatus) were collected weekly from a natural lake during the period mid-April to mid-September. The fish were weighed, state of maturity determined and RNA-DNA ratio of white muscle was measured. Water temperature and primary production were measured in the lake. RNA-DNA ratio declined during the spawning season, reaching a low in mid-May, then increased steadily during the remainder of the year. RNA-DNA ratio was significantly correlated with body weight. The correlation was improved if RNA-DNA ratio was paired with weight for the following week. The correlation was further improved when the spawning season was removed from the data set. Both weight and RNA-DNA ratios were significantly correlated with water temperature, as expected. The correlations were again improved if water temperature was paired with weight and RNA-DNA values for the following week. Weight and RNA-DNA ratio were also correlated with primary production when the correlation was made with concurrent values, and the correlations were improved when RNA-DNA ratio or weight were paired with primary production values for the previous month. RNA-DNA ratio was determined to be a useful predictor of skeletal muscle growth in natural populations of fish over short (ca. one week) time intervals.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 207 (1980), S. 1-11 
    ISSN: 1432-0878
    Schlagwort(e): Heart(rat) ; Ultrastructural radioautography ; Protein synthesis ; Atrial specific granules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sections of atrial cardiocytes from young rats were subjected to radioautography after a single intravenous injection of L-leucine-4,5 3H to identify the sites of synthesis and to follow the migration of newly-formed proteins. As early as 2 min after injection of L-leucine 3H, the label was highest in the rough endoplasmic reticulum (RER), suggesting that cisternal ribosomes are sites of protein synthesis. By 5 min, most of the label had migrated from the RER to the Golgi complex. Some label was already present over specific granules by 2 min but the peak was reached at 1 h. By 4 h, the label over the specific granules had diminished, possibly indicating a release of newly-synthetized secretory material outside the cell. The label over myofilaments and Z-bands was relatively high at most time intervals, suggesting an early and important incorporation of leucine into the contractile and structural proteins of these organelles. The label over the cytosol was initially high and increased even further at 5 and 20 min but decreased to a very low level at 4 h. In contrast, the label over the cell surface rose continuously and peaked at 4 h. The pattern of increment of the label over the cell surface suggests that the newly-formed proteins of these sites are also synthetized in the RER, pass through the Golgi complex and are transported in the cytosol before reaching their destination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 208 (1980), S. 261-281 
    ISSN: 1432-0878
    Schlagwort(e): Choroid plexus ; Ependyma ; Apocrine secretion ; Protein synthesis ; Electron microscope autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Licht- (LM-ARG) und elektronenmikroskopische (EMARG) Autoradiographien des Plexus chorioideus und des Ependyms von jungen Ratten wurden nach der Injektion von Tritium-markierten Aminosäuren angefertigt. Die Ratten wurden in Zeitabständen von 5, 10, 30, 60 min und 16 h getötet. Intracelluläre Proteinsynthese und Transport wurden im Plexus chorioideus der lateralen und des vierten Ventrikels mit quantitativer Autoradiographie bestimmt. Autoradiographische Experimente wurden auch an kultiviertem Plexus chorioideus-Gewebe durchgeführt. Diese Serie wurde nach eintägigem Wachstum in vitro für 1 h mit 3H-Phenylalanin markiert, anschließend gewaschen und für weitere Zeitperioden kultiviert. Hohe Inkorporation der markierten Substanzen wurde in gestielten und freien “blebs” des Plexus chorioideus und des Ependyms in vivo und des Plexus chorioideus in vitro gefunden. Dieses Ergebnis wurde als ein physiologisch bedeutender Mechanismus des Protein-Transportes (apokrine Sekretion) von den Epithelzellen in den Liquor cerebrospinalis gedeutet.
    Notizen: Summary Light (LM-ARG) and electron microscope (EM-ARG) autoradiographs were prepared from immature rat choroid plexus and ependyma at 5, 10, 30, and 60 min and 16 h following intraperitoneal administration of [3H]- labeled amino acid mixtures. Intracellular protein synthesis and transport were ascertained in lateral and fourth ventricle choroid plexus epithelium by quantitative EM-ARG at the several post-injection intervals. ARG were also prepared from choroid plexuses cultured for one day, pulse labeled for one hour and reincubated for various periods in nonradioactive media. Significant labeling of both attached and free apical protrusions (blebs) was observed in both choroid plexus and ependyma in vivo and in choroid plexus in vitro. This phenomenon was interpreted as a physiologically significant mechanism for protein transport (apocrine secretion) by epithelia into the cerebrospinal fluid (CSF).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 264-268 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Wasser in Organ. Lösungsmitteln ; Chromatographie, Gas ; ECD, 8–170 ppm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Wasser ist in organischen Lösungsmitteln im ng-Bereich gas-chromatographisch ohne Derivatisierung mittels eines linearisierten Elektroneneinfangdetektors (ECD) nach Abtrennung auf einer Porapak QS-Säule bestimmbar. Ausreichend wasserfreie Lösungsmittel ließen sich durch Trocknen mit aktivierten 4 Å-Molekularsieben oder superaktiven Aluminiumoxiden W 200, Woelm Pharma, Eschwege, herstellen. Um Wasserblindwerte aus der Raumluft auszuschließen, ist es notwendig, sämtliche Operationen in einer Box mit Umlauftrocknung durchzuführen. Wassermengen bis zu 15 ng absolut sind bestimmbar. Im Konzentrationsbereich 7–150 μg/ml ist die Detektoranzeige für Wasser linear.
    Notizen: Summary Water can be determined directly in organic solvents in the ng range after separation on a porapak-QS column using a linear electron-capture detector (ECD). Organic solvents can be dried by activated 4 Å molecular sieves to a water content of 5 μg/ml, about 0.3×10−3 molar. To exclude water contamination all operations, storage of solvents and standards included, were made in a glove box with permanent drying of the inside atmosphere. The EC-detector allows to determine 15 ng of water absolute. In the range of 7–150 μg/ml a linear response for water by the ECD has been found.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 20-22 
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Biolog. Substanzen, Steroidhormonen ; Chromatographie, Gas ; Anreicherungsverfahren
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary A new technique for the quantitation of very low concentrations of biological substances by gas-liquid chromatography is described. It is based on the direct concentration of the substances to be measured at the inlet of the chromatographic column. This is accomplished by injection of the substance into the chromatographic apparatus, whose column is kept at the condensation temperature of the sample. Repeated injection in separate portions results in accumulation of the substance. Chromatography is readily achieved by heating to the optimal temperature. This technique yielded promising results in the quantitation of several steroid hormones.
    Notizen: Zusammenfassung Das Verfahren beruht auf der direkten Konzentrierung der zu bestimmenden Substanzen am Eingang der chromatographischen Säule. Sie erfolgt durch Injektion der Substanzlösung in die Säule bei einer Temperatur niedriger als der Schmelzpunkt, so daß die Substanz nicht eluiert werden kann. Eine wiederholte Injektion einzelner Portionen führt zur Anreicherung der Substanz, die dann nach Erhöhung der Säulentemperatur chromatographiert werden kann. Das Verfahren wurde mit guten Ergebnissen zur Bestimmung einiger Steroidhormone angewendet.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 300 (1980), S. 387-402 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Hexachlorbenzol, Polychlorcamphenen, Toxaphen, Kohlenwasserstoffen, chlorierte in Biolog. Material ; Chromatographie, Gas ; Umweltbelastung
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary Fishes have been used to characterize pristine aquatic environments. In samples from a lake in the Tyrolian Alps (arctic char) and Northwest Ireland (pike), the Caspian Sea (sturgeon/Sevruga), the North Atlantic (salmon), the North Pacific (salmon) and the Antarctic Ocean at South Georgia (antarctic cod) hexachlorobenzene and polychlorinated camphene (PCC, Toxaphene) have been found. Samples are extracted by n-hexane/acetone (2+1), following a dimethylformamide/hexane clean-up of the lipid matrix. Adsorption chromatography on Florisil (1.25% water content) allows the elution of hexachlorobenzene, 4,4′-DDE and the polychlorobiphenyls (PCB) with n-hexane, while the mixture nhexane/diethyl ether (90+10) will elute the polychlorocamphenes (PCC) together with the hexachlorocyclohexane isomers and the DDT group. Identification of the PCC has been done by matching their retention indices measured by high resolution ECD glass capillary gas chromatography using the nalkyl-trichloroacetates as references and technical Toxaphene together with a slightly dehydrochlorinated product as authentic samples. The PCC content of the samples from the lakes in the European Alps and Northwest-Ireland, the North Pacific and the Antarctic Ocean was 125, 240, 285 and 68 ng of PCC per g of extractable lipids, respectively. The samples from the Caspian Sea and the North Atlantic had 1,625 and 3,500 ng of PCC per g of extractable lipids, respectively. All samples but the one from the Antarctic Ocean (liver) were spawn. Besides hexachlorobenzene and the PCC all samples contained polychlorobiphenyls (PCB), theα, β andγ-isomers of hexachlorocyclohexane, the compounds of the DDT-group and many other ECD-dectable not yet identified compounds.
    Notizen: Zusammenfassung In Fischproben aus in erster Näherung unbelasteten Gebieten, dem Nordatlantik (Lachs), einem See in Nordwest-Irland (Hecht), einem Hochalpensee (Bergsaibling), dem Kaspischen Meer (Sternhausen), dem Nordpazifik (Lachs) und dem Antarktischen Ozean bei Südgeorgien (Antarktischer Dorsch) lassen sich Hexachlorbenzol und polychlorierte Camphene (PCC, Toxaphen®) nachweisen. Die Probe wird mit n-Hexan/Aceton (2+1) extrahiert. Die Lipide werden über eine Dimethylformamid/Hexan-Verteilung weitgehend abgetrennt. Adsorptions-Chromatographie an Florisil mit 1,25% Wassergehalt erlaubt die Elution von Hexachlorbenzol, 4,4′-DDE und der polychlorierten Biphenyle (PCB) mit n-Hexan; n-Hexan/Diethylether (90+10) eluiert die polychlorierten Camphene zusammen mit den Hexacyclohexan-Isomeren und der DDT-Gruppe. Die Identifizierung der PCC gelang über Vergleich der mit ECD-Capillar-Gas-Chromatographie unter Bezug auf die n-Alkyltrichloracetate gemessenen Retentionsindices. Als Standardsubstanz diente technisches Toxaphen, sowie ein durch methanolische KOH leicht dehydrochloriertes Produkt. Der PCC Gehalt lag bei den Proben aus dem Hochalpensee, einem See in Nordwest-Irland, dem Nordpazifik und dem Antarktischen Ozean bei 125, 240 bzw. 285 und 68 ng PCC/g extrahierbare Lipide. Die Proben aus dem Kaspischen Meer und dem Nordatlantik enthielten 1 625 bzw. 3 500 ng PCC/g extrahierbare Lipide. Bis auf die Probe aus der Antarktis (Leber) handelte es sich jeweils um Rogen. Neben dem Hexachlorbenzol und den Polychlorcamphenen wurden in allen Proben polychlorierte Biphenyle, dieα, β undγ-Isomeren des Hexachlorcyclohexans, die DDT-Gruppe und zahlreiche weitere bisher nicht identifizierte, mit dem ECD nachzuweisende Verbindungen gefunden.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 20-31 
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Polychlorbiphenylen, Aroclor, Clophen ; Chromatographie, Gas ; Glascapillaren, Electron capture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary The composition of seven technical PCB-mixtures (Aroclor [Monsanto, USA] und Clophen A [Bayer, FRG]) has been investigated by high-resolution thin-film glass capillary gas chromatography with electron-capture detector. Methylpolysiloxane (SE 30) and purified Apiezon L have been used as liquid phases. Identification of the single PCB components has been performed by comparison of their retention indices with those of polychlorinated biphenyls defined by synthesis or with values calculated from retention index increments. For marking the individual PCB compounds a systematic numbering has been used.
    Notizen: Zusammenfassung Die Zusammensetzung sieben technischer Gemische polychlorierter Biphenyle (PCB) mit unterschiedlichem Chlorierungsgrad (Aroclor- [Monsanto, USA] und Clophen A- [Bayer, Bundesrepublik Deutschland]-Typen) wurde mit hochauflösender Gas-Chromatographie mit Elektroneneinfang-Detektion in Dünnfilm-Glascapillaren mit Methylpolysiloxan (SE 30) und gereinigtem Apiezon L als flüssiger Phase untersucht. Die Identifizierung der Einzelkomponenten erfolgte durch chromatographischen Vergleich mit definierten Referenzsubstanzen oder Vergleich der aus Inkrementen berechneten Retentionsindices. Für die Kennzeichnung der Einzelkomponenten wird eine systematische Numerierung entsprechend der Substituentenbezifferung verwendet.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 304 (1980), S. 23-27 
    ISSN: 1618-2650
    Schlagwort(e): Best. von n-Butylzinnverbindungen in Luft ; Chromatographie, Gas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung n-Butylzinnverbindungen (Tetra-, Tri-, Di-) wurden aus der angesaugten Luft an Chromosorb 102 adsorbiert, mit HCl-haltigem Diethylether desorbiert, falls nötig mit Methylmagnesiumchlorid umgesetzt und die methylierten Verbindungen gas-chromatographisch mit einem zinnspezifischen flammenphotometrischen Detektor bestimmt. Die mittlere Wiederfindungsrate (0,09–40 μg) von Bis(tri-n-butylzinn)oxid (TBTO) betrug: 93,3%; Streubereich der Einzelwerte ± 9,3% (P=95%, N=11). Wird 1 m3 Luft angesaugt, lassen sich noch Konzentrationen an n-Butylzinnverbindungen (Tetra-, Tri-, Di-) von 0,05 μg/m3 bestimmen. In einem mit einer TBTO-haltigen Dispersionsfarbe gestrichenen Raum wurde die Temperaturabhängigkeit der Tri-n-butylzinn-Konzentration in der Luft untersucht. Der Vergleich mit den Resultaten von Bestimmungen des Totalzinngehaltes läßt den Schluß zu, daß in der Luft nur Tri-n-butylzinnverbindungen vorlagen.
    Notizen: Summary n-Butyltin compounds (tetra-, tri-, di-) have been adsorbed on Chromosorb 102 from the aspired air, desorbed with HCl-containing diethylether and, if necessary, converted to the corresponding methyl derivatives by reaction with methylmagnesium chloride. The derivatives were determined by GLC with a tin-specific flame photometric detector. The mean recovery (0.09–40 μg) of bis(tri-n-butyltin)oxide (TBTO) was 93.3%; tolerance limit ±9.3% (P=95%, N=11). With an air sample of 1 m3 it is possible to measure n-butyltin compounds (tetra-, tri-, di-) in concentrations down to 0.05 μg/m3. In a room coated with a TBTO-containing latex-based paint, the temperature dependence of the tri-n-butyltin concentration in the air has been studied. Comparison with results of total tin determinations allows the conclusion that the air contained only tri-n-butyltin compounds.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 143-143 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Phenolen ; Chromatographie, Gas ; neue Methylierungsreagentien
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 432-433 
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Abwasser der Dimethylterephthalat-Produktion ; Chromatographie, Gas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 126-127 
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Hydroxyfettsäuren ; Chromatographie, Gas ; ECD
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 279-288 
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Polysacchariden, Verdikkungsmitteln, Celluloseethern ; Chromatographie, Gas ; Zeisel-Spaltung
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Im vorliegenden zweiten Teil der dreiteiligen Übersicht zur Analytik der Polysaccharide wird am Beispiel einer Methylhydroxyethylcellulose (MHEC) die Erfassung der Celluloseether und -mischether mittels der Gas-Chromatographie vorgestellt. Dabei handelt es sich um die Beschreibung einer quantitativen Methode hoher Empfindlichkeit, die erforderlich ist, um Cellulosederivate mit geringer Mischsubstitution zu identifizieren und zu unterscheiden. Dazu werden die Celluloseether in einer speziell entwickelten Apparatur mit Iodwasserstoffsäure bei 140°C erhitzt. Von den sich bildenden Spaltprodukten werden die abdestillierten Alkyliodide in gekühltem Hexylbromid aufgefangen, gas-chromatographisch getrennt und identifiziert; gebildete Olefine werden durch Bromaddition erfaßt. Reproduzierbarkeit: ≤3% rel. Erfassungsgrenze: = 0,01% Hydroxyethylcellulose (HEC). Die Methode eignet sich auch zur Erfassung von Estern, S-Alkylgruppen, Methylimidverbindungen, Glykolanteilen oder bestimmten Tensiden.
    Notizen: Summary In this second part of the three-part review on analysis of polysaccharides the characterization of cellulose ethers and cellulose mixed ethers by means of gaschromatography is described. The identification of the wide varying field of this cellulose ethers is presented using methylhydroxyethylcellulose (MHEC) as an example. To differentiate all cellulose mixed ethers, even those with little substitution of one of the two ether components, the method has to work qualitatively and quantitativly with a high sensitivity. The cellulose ethers are treated with hydriodic acid at 140°C in a special apparatus. The alkyliodides formed are distilled into cooled hexyl bromide. They are separated and identified by gaschromatography. Olefins also formed are determined by addition of bromine. Reproducibility: ≤ 3% rel. Limit of detection: = 0.01 % Hydroxyethylcellulose (HEC). This method can also be used for the determination of esters, S-alkyl groups, methylimides, glycols and some detergents.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 397-400 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Benzo(a)-pyren in Erdölprodukten ; Chromatographie, Gas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary A gas-liquid chromatographic method has been developed for the quantitive determination of benzo(a)-pyrene in petroleum products. At the 2 ppb benzo(a)pyrene level in a sample, the recovery is 87–90%. The detection limit is 50 ng. A column was employed with a liquid-crystal phase of bis(p-phenylbenzylidene)-bi-p-toluidine on Chromosorb.
    Notizen: Zusammenfassung Das entwickelte gas-chromatographische Verfahren benutzt eine SÄule mit der Flüssig-Kristallphase von Bis(p-phenylbenzyliden)-bi-ptoluidin auf Chromosorb und gestattet im Bereich von 2 ppb Benzo(a)-pyren eine Wiederfindung von 87–90%. Die Nachweisgrenze liegt bei 50 ng.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 32-32 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Hexachlorcyclohexan, Hexachlorbenzol in Boden ; Chromatographie, Gas ; Extraktion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 304 (1980), S. 143-143 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Hexachlorcyclohexan, Hexachlorbenzol im Wasser ; Chromatographie, Gas ; Extraktion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 375-381 
    ISSN: 1618-2650
    Schlagwort(e): Best. von n-Alkanen, Pristan in Luft ; Chromatographie, Gas ; reine Luft
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary An analytical method was developed for measuring n-alkanes (C9 to C17) and other hydrocarbons in tropospheric air with mixing ratios of a few ppt (10−12) and higher. The hydrocarbons are collected in situ in absorption tubes, carefully protected against contamination and analysed later in the laboratory by gas chromatography. First data are reported for Atlantic air masses at the west coast of Ireland.
    Notizen: Zusammenfassung Es wurde eine analytische Methode entwickelt zur Messung der n-Alkane (C9 bis C17) und anderer Kohlenwasserstoffe in reiner troposphärischer Luft mit Mischungsverhältnissen von einigen ppt (10−12) und aufwärts. Die Kohlenwasserstoffe wurden am Beobachtungsort angereichert, sorgfältig gegen Verunreinigung geschützt und später im Laboratorium gas-chromatographisch analysiert. Erste Daten für atlantische Luftmassen an der Westküste Irlands werden mitgeteilt.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 398-401 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Wasserstoff in Magnesium ; Chromatographie, Gas ; Kapselmethode
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary A new method, the capsule method, has been developed for analyzing hydrogen in magnesium with a standard deviation of about 4%. 1–2 g samples are made with a smooth surface and enclosed in a degassed iron capsule. The surface humidity is removed by a short annealing at 400°C, and the sample is subsequently degassed at 500–620°C in vacuum. The extracted hydrogen is measured by gas chromatography. The commercial magnesium analyzed contained from 0.2 to 8 ppm of hydrogen. The diffusion coefficient of hydrogen was measured to be: D=D 0e−Q/RT; where D 0=9.5 · 10−6 m2/s and Q=46,400 Joule/mole. The results obtained were interpreted as interstitial diffusion of hydrogen in magnesium.
    Notizen: Zusammenfassung Zur Analyse von Wasserstoff in Magnesium wurde eine neue Methode, die Kapselmethode, entwickelt, 1–2 g schwere Proben werden mit einer glatten Oberfläche hergestellt und in eine gasfreie Kapsel eingeschlossen. Die Oberflächenfeuchtigkeit wird durch kurzes Anlassen bei 400°C entfernt und die Probe wird danach bei 500–620°C im Vakuum entgast. Der entfernte Wasserstoff wird mit einem Gas-Chromatographen gemessen. Die Standardabweichung beträgt etwa 4%. Das untersuchte technische Magnesium enthält zwischen 0,2 und 8 ppm Wasserstoff. Der gemessene Diffusionskoeffizient für Wasserstoff ist: D=D 0e−Q/RT; D 0=9.5 · 10−6 m2/s und Q= 46400 Joule/Mol. Die erhaltenen Resultate wurden als interstitielle Wasserstoffdiffusion im Magnesium interpretiert.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 389-393 
    ISSN: 1618-2650
    Schlagwort(e): Best. von Chrom(III), Chrom(VI) in Wasser ; Chromatographie, Gas ; Extraktion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary The gas-chromatographic determination of Cr(III) and Cr(VI) in aqueous solution using di(trifluoroethyl)dithiocarbamate as an extracting agent (pH 3) is described. Best results were obtained with a column of OV-25 (3% on Chromosorb HPW, 100–120 mesh, 160–210
    Notizen: Zusammenfassung Die Extraktion mit dem Reagens wird bei pH 3 durchgeführt. Als SÄulenmaterial hat sich am besten OV-25 (3% auf Chromosorb HPW, 100–120 mesh, 160–210
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 304 (1980), S. 337-349 
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Biphenylen, polychlorierten in Umweltmaterial ; Chromatographie, Gas ; Glascapillar
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary The PCB-pattern of biological environmental samples of different trophic levels (fish, bird, man) and geographic areas (Alps, North Sea, North Atlantic) as seen by high-resolution glass capillary gas chromatography with electron capture detection is presented. The most evident variation of the pattern compared to a best fit simulation by technical mixtures is found for warm blooded species (eggs of birds and human milk). Only one trichloro-, but nine tetrachloro-biphenyls and 55 penta-to octachloro-biphenyls have been identified as PCB-components in biological samples. Compounds with 4,4′-disubstitution degrade very slowly, if at all (1,4-recalcitrance principle). Single component analysis of PCB in marine samples using glass capillary gas chromatography needs the preseparation from the ubiquitous polychloroterpenes (toxaphene, polychlorocamphene) and the DDT-group. Both complex mixtures can be separated successfully by adsorption chromatography on Florisil. Quantitation of PCB as a sum has been done by using recalcitrant diagnostic components and PCB-Clophen A 60 as the reference standard.
    Notizen: Zusammenfassung Die Bestimmung der Einzelkomponenten der polychlorierten Biphenyle (PCB) in Umweltproben durch Glascapillar-Gas-Chromatographie auf Methylsilicon- oder Apiezon L-Phasen erfordert eine Vortrennung von den Polychlorterpenen (Toxaphen, Polychlorcamphen) und der DDT-Gruppe. Diese Trennung gelingt durch Adsorptions-Chromatographie auf Florisil. Die PCB-Muster im Fett des phytoplanktonfressenden Seefisches Menhaden (Brevoortia tyrannus) aus dem Nordatlantik, im Rogen der zooplanktonfressenden Salmoniden Seesaibling (Salvelinus alpinus) und Bachforelle (Salmo trutta m. fario) aus Bergseen in Tirol, und in der Leber der Süßwasserdorschart Quappe (Lota lota) aus dem Bodensee werden gezeigt. Die stärksten Veränderungen gegenüber einer aus technischen Gemischen hergestellten Simulationsmischung werden für Warmblütlerproben — Eier von Brandgans (Tadorna tadorna) und Küsten-Seeschwalbe (Sterna paradisea); Humanmilch — gefunden. Neben einem Trichlor- und neun Tetrachlorbiphenylen wurden 55 Pentabis Octachlorbiphenyle nachgewiesen. Komponenten mit einer 4 und/oder 3,5-Substitution in beiden Ringen werden beträchtlich langsamer abgebaut als anders strukturierte Komponenten (1,4-Rekalzitranz-Prinzip). Die Quantifizierung der PCB als Summe erfolgte über schwer abbaubare, signifikante Hauptkomponenten unter Verwendung eines Clophen A 60 PCB-Gemisches als Eichstandard.
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