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  • 2000-2004
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  • 1
    Publication Date: 2014-02-26
    Description: In this paper we consider the multiple knapsack problem which is defined as follows: given a set $N$ of items with weights $f_i$, $i \in N$, a set $M$ of knapsacks with capacities $F_k$, $k \in M$, and a profit function $c_{ik}, i \in N, k \in M$; find an assignment of a subset of the set of items to the set of knapsacks that yields maximum profit (or minimum cost). With every instance of this problem we associate a polyhedron whose vertices are in one to one correspondence to the feasible solutions of the instance. This polytope is the subject of our investigations. In particular, we present several new classes of inequalities and work out necessary and sufficient conditions under which the corresponding inequality defines a facet. Some of these conditions involve only properties of certain knapsack constraints, and hence, apply to the generalized assignment polytope as well. The results presented here serve as the theoretical basis for solving practical problems. The algorithmic side of our study, i.e., separation algorithms, implementation details and computational experience with a branch and cut algorithm are discussed in the companion paper SC 93-07.
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  • 2
    Publication Date: 2014-02-26
    Description: The Lanczos iteration for symmetric indefinite linear systems seems to be well--known for quite a while. However, in order to modify it with the aim of improved performance, the present paper studies certain aspects in terms of an adjoint scalar three--term recurrence. Thus, at least a different view is opened. Moreover, an alternative $3n$--implementation in terms of the Euclidean orthogonal basis has been found that easily permits generalizations. The study is understood as a start--off for further numerical investigations and experiments.
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  • 3
    Publication Date: 2020-10-02
    Description: We consider the discretization of obstacle problems for second order elliptic differential operators in three space dimensions by piecewise linear finite elements. Linearizing the discrete problems by suitable active set strategies, the resulting linear sub--problems are solved iteratively by preconditioned cg--iterations. We propose a variant of the BPX preconditioner and prove an $O(j)$ estimate for the resulting condition number. To allow for local mesh refinement we derive semi--local and local a posteriori error estimates. The theoretical results are illustrated by numerical computations.
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  • 4
    Publication Date: 2014-02-26
    Description: \def\KPA{\hbox{\rm KPA}}\def\A{{\rm A}}\def\KPW{\hbox{\rm KPW}}\def\W{{\rm W}}\def\B{{\rm B}} \def\D{{\rm D}} Recently M.~M.~Kapranov [Kap] defined a poset $\KPA_{n-1}$, called the {\it permuto-associahedron}, which is a hybrid between the face poset of the permutahedron and the associahedron. Its faces correspond to the partially parenthesized, ordered, partitions of the set $\{1,2,\ldots,n\}$, with a natural partial order. Kapranov showed that $\KPA_{n-1}$ is the face poset of a CW-ball, and explored its connection with a category-theoretic result of MacLane, Drinfeld's work on the Knizhnik-Zamolodchikov equations, and a certain moduli space of curves. He also asked the question of whether this CW-ball can be realized as a convex polytope. We show that this permuto-associahedron corresponds to the type $\A_{n-1}$ in a family of convex polytopes $\KPW$ associated to each of the classical Coxeter groups, $\W = \A_{n-1}, \B_n, \D_n$. The embedding of these polytopes relies on the secondary polytope construction of the associahedron due to Gel'fand, Kapranov, and Zelevinsky. Our proofs yield integral coordinates, with all vertices on a sphere, and include a complete description of the facet-defining inequalities. Also we show that for each $\W$, the dual polytope $\KPW^*$ is a refinement (as a CW-complex) of the Coxeter complex associated to $\W$, and a coarsening of the barycentric subdivision of the Coxeter complex. In the case $\W=\A_{n-1}$, this gives an elementary proof of Kapranov's original sphericity result.
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  • 5
    Publication Date: 2020-11-13
    Description: In this paper we describe and discuss a problem that arises in the (global) design of a main frame computer. The task is to assign certain functional units to a given number of so called multi chip modules or printed circuit boards taking into account many technical constraints and minimizing a complex objective function. We describe the real world problem. A thorough mathematical modelling of all aspects of this problem results in a rather complicated integer program that seems to be hopelessly difficult -- at least for the present state of integer programming technology. We introduce several relaxations of the general model, which are also $NP$-hard, but seem to be more easily accessible. The mathematical relations between the relaxations and the exact formulation of the problem are discussed as well.
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  • 6
    Publication Date: 2014-02-26
    Description: Cascadic conjugate gradient methods for the numerical solution of elliptic partial differential equations consists of Galerkin finite element methods as outer iteration and (possibly preconditioned) conjugate gradient methods as inner iteration. Both iterations are known to minimize the energy norm of the arising iterations errors. A simple but efficient strategy to control the discretization errors versus the PCG iteration errors in terms of energy error norms is derived and worked out in algorithmic detail. In a unified setting, the relative merits of different preconditioners versus the case of no preconditioning is compared. Surprisingly, it appears that the cascadic conjugate gradient method without any preconditioning is not only simplest but also fastest. The numerical results seem to indicate that the cascade principle in itself already realizes some kind of preconditioning. A theoretical explanation of these observations will be given in Part II of this paper.
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  • 7
    Publication Date: 2014-02-26
    Description: This paper throws light on the connection between the optimal condition number estimate for the BPX method and constructive approximation theory. We provide a machinery, which allows to understand the optimality as a consequence of an approximation property and an inverse inequality in $H^{1+\epsilon}$, $\epsilon 〉 0$. This machinery constructs so-called {\em approximation spaces}, which characterize a certain rate of approximation by finite elements and relates them with interpolation spaces, which characterize a certain smoothness.
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  • 8
    Publication Date: 2020-08-05
    Description: "`Telebus"' ist der soziale Behindertenfahrdienst im Land Berlin. Das Telebus-Forschungsprojekt des Konrad-Zuse-Zentrums für Informationstechnik (ZIB) hat das Ziel, den Fahrdienst (insbesondere die Disposition der Telebusse) zu verbessern, d.h. kundenfreundlicher zu gestalten und gleichzeitig billiger zu machen. In diesem Bericht werden die bisherigen Ergebnisse dargestellt und weitere Möglichkeiten zur Verbesserung des Service und zur Reduzierung der Kosten skizziert. \originalTeX
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    Language: German
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  • 9
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    Publication Date: 2014-02-26
    Description: These lecture notes have several aims: \begin{itemize} \item to give an introduction to some basic facts about convex polytopes, with an emphasis on the basic methods that yield them (Fourier-Motzkin elimination, Schlegel diagrams, shellability, Gale transforms and oriented matroids), \item to discuss some important examples and elegant constructions (cyclic and neighborly polytopes, zonotopes, Minkowski sums, permutahedra and associahedra, fiber polytopes, the Lawrence construction) \item and to illustrate why polytope theory is exciting, with highlights like Kalai's new diameter bounds, the construction of non-rational polytopes, the Bohne-Dress tiling theorem, shellability and the upper bound theorem, .... \end{itemize} For several of these topics the decisive break-through is very recent, which suggests that there is much more discovered.
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  • 10
    Publication Date: 2020-03-11
    Description: GRAZIL ist ein interaktives Programmpaket zur grafischen Darstellung von zwei-dimensionalen Kurvenverläufen. Dem Benutzer stehen zahlreiche Kommandos und ein grafisches User-Interface zum Gestalten des Layouts der Zeichnung zur Verfügung. Die Eingabedaten müssen dem GRAZIL-Eingabe-Format genügen. Somit wird eine hohe Flexibilität und eine gro\"se Bandbreite der Einsatzmöglichkeiten erreicht. GRAZIL wurde mit der grafischen Grundsoftware GKS entwickelt. Dadurch kann ein breites Rechner- und Ausgabegerätespektrum genutzt werden.
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    Language: German
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  • 11
    Publication Date: 2019-05-10
    Description: The KASKADE toolbox defines an interface to a set of C subroutines which can be used to implement adaptive multilevel Finite Element Methods solving systems of elliptic equations in two and three space dimensions. The manual contains the description of the data structures and subroutines. The main modules of the toolbox are a runtime environment, triangulation and node handling, assembling, direct and iterative solvers for the linear systems, error estimators, refinement strategies, and graphic utilities. Additionally, we included appendices on the basic command language interface, on file formats, and on the definition of the partial differential equations which can be solved. The software is available on the ZIB ftp--server {\tt elib} in the directory {\tt pub/kaskade}. TR 93--5 supersedes TR 89--4 and TR 89--05.
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  • 12
    Publication Date: 2020-10-02
    Description: In this paper various algorithms for rendering gaseous phenomena are reviewed. In computer graphics such algorithms are used to model natural scenes containing clouds, fog, flames and so on. On the other hand it has become an important technique in scientific visualization to display three dimensional scalar datasets as cloudy objects. Our emphasis is on this latter subject of so-called {\em direct volume rendering}. All algorithms will be discussed within the framework of linear transport theory. The equation of transfer is derived. This equation is suitable to describe the radiation field in a participating medium where absorption, emission, and scattering of light can occur. Almost all volume rendering algorithms can be shown to solve special cases of the equation of transfer. Related problems like the mapping from data values to model parameters or possible parallelization strategies will be discussed as well.
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  • 13
    Publication Date: 2014-02-26
    Description: This report describes the new object oriented implementation of extrapolation codes {\sc Eulex, Eulsim, Difex} for ordinary differential equations. The resulting C++ class library provides a simple and flexible interface to these methods and incorporates advanced features like continuous output and order-stepsize freezing. The interface of the ODE classes allows in particular a user-defined solver for the linear systems occuring in the linearly implicit discretization scheme. The library also provides some classes for numerical objects such as vectors and (full) matrices. Due to the underlying data-view concept it is possible to access substructures without copying. In addition, we included several utility classes such as a timer and a minimal command language that may be useful in other contexts, too.
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  • 14
    Publication Date: 2014-02-26
    Description: Aus dem Inhalt: Vorwort; Leonhard Euler - aus der Zeit seines Wirkens in Berlin; Introductory Remarks.
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    Language: German
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  • 15
    Publication Date: 2014-02-26
    Description: The problem of nonlocal correlation and symmetry in space is of great importance in physical phenomena like the \underline{Einstein-Poloski-Rosen-Paradox} and others. It is shown that in Cellular Automata (Rechnender Raum) the structure of the space offers solutions for such problems.
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  • 16
    Publication Date: 2014-02-26
    Description: A software package for the adaptive solution of time--dependent reaction--diffusion systems and linear elliptic systems in one space dimension is presented. The used algorithm is based on fundamental arguments in J.~Lang, A.~Walter: {\it A Finite Element Method Adaptive in Space and Time for Nonlinear Reaction--Diffusion Systems.} IMPACT of Computing in Science and Engineering, 4, p.~269--314 (1992). Here, only brief outlines of the algorithm are given. This software package is based on the KASKADE toolbox B.~Erdmann, J.~Lang, R.~Roitzsch: {\it KASKADE -- Manual.} To appear as Technical Report TR 93--5, Konrad--Zuse--Zentrum (ZIB) (1993).
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  • 17
    Publication Date: 2014-02-27
    Description: A new approach to inexact Gauss Newton methods for the solution of underdetermined nonlinear problems is presented. It is based on a convergence theorem being invariant under affine transformations of the domain and results in an easily implementable accuracy matching strategy for the arising linear subproblems which guarantees the quadratic convergence. Thanks to the weak assumptions on the given nonlinear problem, the results provide a general framework for multilevel Newton and continuation methods. As an example, a new multilevel Newton h-p collocation method for boundary value problems of ordinary differential equations is developed. It combines the inexact Newton method with a linear collocation solver using adaptive refinement and variable orders. The performance of the resulting C++ class library {\sc Cocon} is demonstrated by some numerical examples including singular perturbed problems. In addition, the new method is applied to a realistic railway bogie model in which a branch of periodic solutions emanates from a branch of fixed points at a Hopf bifurcation.
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    Language: English
    Type: doctoralthesis , doc-type:doctoralThesis
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  • 18
    Publication Date: 2014-02-27
    Description: A new method for the numerical solution of highly nonlinear, coupled systems of parabolic differential equations in one space dimension is presented. The approach is based on a classical method of lines treatment. Time discretization is done by means of the semi--implicit Euler discretization. Space discretization is done with finite differences on non--uniform grids. Both basic discretizations are coupled with extrapolation techniques. With respect to time the extrapolation is of variable order whereas just one extrapolation step is done in space. Based on local error estimates for both, the time and the space discretization error, the accuracy of the numerical approximation is controlled and the discretization stepsizes are adapted automatically and simultaneously. Besides the local adaptation of the space grids after each integration step (static regridding), the grid may even move within each integration step (dynamic regridding). Thus, the whole algorithm has a high degree of adaptivity. Due to this fact, challenging problems from applications can be solved in an efficient and robust way.
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    Type: doctoralthesis , doc-type:doctoralThesis
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  • 19
    Publication Date: 2014-02-26
    Description: We present an algorithm that is able to confirm projective incidence statements by carrying out calculations in the ring of all formal determinants (brackets) of a configuration. We will describe an implementation of this power and present a series of examples treated by the prover, including {\it Pappos' and Desargues' Theorems,} the {\it Sixteen Point Theorem, Saam's Theorem, }the {\it Bundle Condition,} the uniqueness of a harmonic Point and {\it Pascal's Theorem.}
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  • 20
    Publication Date: 2020-12-14
    Description: We consider the important practical and theoretical problem of designing a low-cost communications network which can survive failures of certain network components. Our initial interest in this area was motivated by the need to design certain ``two-connected" survivable topologies for fiber optic communication networks of interest to the regional telephone companies. In this paper, we describe some polyhedral results for network design problems with higher connectivity requirements. We also report on some preliminary computational results for a cutting plane algorithm for various real-world and random problems with high connectivity requirements which shows promise for providing good solutions to these difficult problems. \def\NP{$\cal NP$}
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  • 21
    Publication Date: 2014-02-26
    Description: The subject of this study is a multilevel Finite Element Method based on an error estimator and step by step grid refinement as an universal tool for solving time--independent Schrödinger--eigenvalue problems. Numerical results for standard problems appearing in vibrational motion and molecular electronic structure calculations are given and discussed.
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  • 22
    Publication Date: 2014-02-26
    Description: In two-parameter systems with symmetry two steady state bifurcation points of different symmetry types coalesce generically within one point. Under certain group theoretic conditions involving the action of the symmetry group on the kernels, we show that secondary Hopf bifurcation is borne by the mode interaction. We explain this phenomenon by using linear representation theory. For motivation an example with $D_3$-symmetry is investigated where the main properties causing the Hopf bifurcation are summarized.
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  • 23
    Publication Date: 2021-03-19
    Description: Adaptive numerical methods using the $h$-$p$-version of finite elements require special kinds of shape functions. Desirable properties of them are symmetry, hierarchy and simple coupling. In a first step it is demonstrated that for standard polynomial vector spaces not all of these features can be obtained simultaneously. However, this is possible if these spaces are extended. Thus a new class of polynomial shape functions is derived, which is well-suited for the $p$- and $h$-$p$-version of finite elements on unstructured simplices. The construction is completed by minimizing the condition numbers of the arising finite element matrices. The new shape functions are compared with standard functions widely used in the literature.
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  • 24
    Publication Date: 2019-05-10
    Description: {\def\enorm {\mathop{\mbox{\boldmath{$|\!|$}}}\nolimits} Let $u \in H$ be the exact solution of a given self--adjoint elliptic boundary value problem, which is approximated by some $\tilde{u} \in {\cal S}$, $\cal S$ being a suitable finite element space. Efficient and reliable a posteriori estimates of the error $\enorm u - \tilde{u}\enorm $, measuring the (local) quality of $\tilde{u}$, play a crucial role in termination criteria and in the adaptive refinement of the underlying mesh. A well--known class of error estimates can be derived systematically by localizing the discretized defect problem using domain decomposition techniques. In the present paper, we provide a guideline for the theoretical analysis of such error estimates. We further clarify the relation to other concepts. Our analysis leads to new error estimates, which are specially suited to three space dimensions. The theoretical results are illustrated by numerical computations.}
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  • 25
    Publication Date: 2014-02-26
    Description: The strategy for solving nonlinear equation systems automatically in the computer algebra system REDUCE is described. Kernel of the solver is a factoring Buchberger algorithm. Pre -- and postprocessors enable the use of the Gröbner techniques in a black box manner. In addition to polynomials equations with surds, trigonometric functions and separable transcendental functions are covered.
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  • 26
    Publication Date: 2014-02-26
    Description: In diesem Aufsatz geben wir einen Bericht über den Stand der elektronischen Fachinformation in der Mathematik in Deutschland. Wir sehen diesen Bereich nicht als ein organisatorisch isoliertes Unterfangen, sondern eingebettet in weltweite Bestrebungen und Entwicklungen in der Informationstechnik, im wissenschaftlichen Publikationswesen und natürlich auch in der Mathematik selber. Unser Artikel endet mit einigen weitreichenden (und einigen Lesern möglicherweise spektakulär erscheinenden) Vorschlägen, die sowohl die Informationsanbieter (wie die Fachinformationszentren und Verlage), die öffentlichen Geldgeber als auch die mathematischen Organisationen (wie z.~B.~ die DMV und die mathematischen Fachbereiche) betreffen. Um den gegenwärtigen Zustand der elektronischen Fachinformation und unsere Gedanken zu diesem Thema adäquat beschreiben zu können, präsentieren wir eine breit angelegte Situationsanalyse. Wir stellen den gegenwärtigen Stand der technologischen Entwicklung im elektronischen Publizieren dar und skizzieren seine Auswirkungen. Wir beschreiben das Feld der Interessen und Kräfte im Bereich des mathematischen Publizierens. Wir geben einen kurzen historischen Abriss der Geschichte der Klassifikation und des Referatewesens und zeigen, wie dieses in die elektronische Fachinformation auf dem Gebiet der Mathematik mündete und dann zum DMV-Projekt Fachinformation führte, das der Anlass zur Abfassung dieses Artikels war. Wir skizzieren die gegenwärtige Rezeption elektronischer Fachinformation in der Mathematik in Deutschland. Ausgehend von einer Darstellung und Bewertung verschiedener Modelle des Referatewesens zeigen wir unter Einbeziehung der vorhandenen technischen Gegebenheiten (elektronische Netze etc.) verschiedene Möglichkeiten zur Liberalisierung und Rationalisierung des weltweiten mathematischen Informationswesens auf. Wir sehen den Austausch von Information in engem Zusammenhang mit dem Austausch von Software im Wissenschaftsbereich und regen auch in diesem Bereich an, internationale Kooperation und Offenheit anzustreben. \originalTeX
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    Language: German
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  • 27
    Publication Date: 2014-02-26
    Description: In this paper we describe a cutting plane based algorithm for the multiple knapsack problem. We use our algorithm to solve some practical problem instances arising in the layout of electronic circuits and in the design of main frame computers, and we report on our computational experience. This includes a discussion and evaluation of separation algorithms, an LP-based primal heuristic and some implementation details. The paper is based on the polyhedral theory for the multiple knapsack polytope developed in our companion paper SC 93-04 and meant to turn this theory into an algorithmic tool for the solution of practical problems.
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  • 28
    Publication Date: 2020-12-14
    Keywords: ddc:000
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  • 29
    Publication Date: 2014-02-26
    Description: One key problem in modern chemistry is the simulation of the dynamical reaction of a molecule subjected to external radiation. This is described by the Schrödinger equation, which, after eigenfunction expansion, can be written in form of a system of ordinary differential equations, whose solutions show a highly oscillatory behaviour. The oscillations with high frequencies and small amplitudes confine the stepsizes of any numerical integrator -- an effect, which, in turn, blows up the simulation time. Larger stepsizes can be expected by averaging these fast oscillations, thus smoothing the trajectories. This idea leads to the construction of a quasiresonant smoothing algorithm (QRS). In QRS, a natural and computationally available splitting parameter $\delta$ controls the smoothing properties. The performance of QRS is demonstrated in two applications treating the selective excitation of vibrational states by picosecond laser pulses. In comparison with standard methods a speedup factor of 60--100 is observed. A closer look to purely physically motivated quasiresonant approximations such as WFQRA shows some additional advantages of the above smoothing idea. Among these the possibility of an adaptive formulation of QRS via the parameter $\delta$ is of particular importance.
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  • 30
    Publication Date: 2020-11-16
    Description: This paper will appear as Chapter 28 of the forthcoming "Handbook on Combinatorics" (editors: R. Graham, M. Grötschel, L. Lovasz) to be published in 1994, by North-Holland.
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  • 31
    Publication Date: 2014-02-26
    Description: An analysis of relaxation oscillations in local Er-doped optically pumped lasers is reported. It is based on a time dependent rate equation model for a quasi-two-level-system with wavelength dependent emission- and absorption cross-sections. For the first time a numerically reliable simulation of the characteristic laser behaviour was possible: the onset and decay of the oscillations, the time-dependent repetition period and the steady state signal output power. The characteristic waveguide parameters, as the erbium-concentration profile, the polarization dependent pump- and signal mode intensity profiles, the scattering losses, the cavity length and the front and rear reflectivities were all taken into account. The basic formulas are general and can also be used for Er-doped fiber lasers. Mathematically the problem can be characterized as a large boundary value problem, which can approximately be replaced by a stiff initial value problem of ordinary differential equations. The used algorithmic replacement procedure is motivated and discussed in detail. Here, pump- and signal evolution versus time are presented for an planar Er-diffused $\rm Ti$:$\rm LiNbO_{3}$ waveguide laser. The numerically obtained results show a nearly quantitative agreement with experimental investigations. Simultanously they supply knowledge about non-measureable (space-dependent population dynamic of the Er-atoms) and till today not measured data (dynamical response of the laser by a sharp peak in the external pump).
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  • 32
    Publication Date: 2014-02-26
    Description: We construct Markov chain algorithms for sampling from discrete exponential families conditional on a sufficient statistic. Examples include generating tables with fixed row and column sums and higher dimensional analogs. The algorithms involve finding bases for associated polynomial ideals and so an excursion into computational algebraic geometry.
    Keywords: ddc:000
    Language: English
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  • 33
    Publication Date: 2014-02-26
    Description: Extending well--known linear concepts of successive subspace correction, we arrive at extended relaxation methods for elliptic variational inequalities. Extended underrelaxations are called monotone multigrid methods, if they are quasioptimal in a certain sense. By construction, all monotone multigrid methods are globally convergent. We take a closer look at two natural variants, which are called symmetric and unsymmetric multigrid methods, respectively. While the asymptotic convergence rates of the symmetric method suffer from insufficient coarse--grid transport, it turns out in our numerical experiments that reasonable application of the unsymmetric multigrid method may lead to the same efficiency as in the linear, unconstrained case.
    Keywords: ddc:000
    Language: English
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  • 34
    Publication Date: 2014-02-26
    Description: Elliptic boundary value problems are frequently posed on complicated domains which cannot be covered by a simple coarse initial grid as it is needed for multigrid like iterative methods. In the present article, this problem is resolved for selfadjoint second order problems and Dirichlet boundary conditions. The idea is to construct appropriate subspace decompositions of the corresponding finite element spaces by way of an embedding of the domain under consideration into a simpler domain like a square or a cube. Then the general theory of subspace correction methods can be applied.
    Keywords: ddc:000
    Language: English
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  • 35
    Publication Date: 2014-02-26
    Description: We prove a natural bijection between the polytopal tilings of a zonotope $Z$ by zonotopes, and the one-element-liftings of the oriented matroid ${\cal M}(Z)$ associated with $Z$. This yields a simple proof and a strengthening of the Bohne-Dress Theorem on zonotopal tilings.
    Keywords: ddc:000
    Language: English
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  • 36
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    Publication Date: 2015-06-01
    Description: Formal Laurent-Puiseux series of the form \[ f(x)=\sum \limits_{k=k_0}^{\infty}a_{k}x^{k/n} \] are important in many branches of mathematics. Whereas {\sc Mathematica} supports the calculation of truncated series with its {\tt Series} command, and the {\sc Mathematica} package {\tt SymbolicSum} that is shipped with {\sc Mathematica} version 2 is able to convert formal series of the type mentioned above in some instances to their corresponding generating functions, in six publications of the author we developed an algorithmic procedure to do these conversions that is implemented by the author, A.\ Rennoch and G.\ Stölting in the {\sc Mathematica} package {\tt PowerSeries}. The implementation enables the user to reproduce most of the results of the extensive bibliography on series of Hansen, E.\ R.: A table of series and products. Prentice-Hall, 1975. Moreover a subalgorithm of its own significance generates differential equations satisfied by the input function.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 37
    Publication Date: 2015-06-01
    Description: {\newcommand{\C}{{\rm {\mbox{C{\llap{{\vrule height1.52ex}\kern.4em}}}}}} \newcommand{\Z} {{\rm {\mbox{\protect\makebox[.2em][l]{\sf Z}\sf Z}}}} \newcommand{\Maple}{{\sc Maple}} Formal Laurent-Puiseux series of the form \[ f(x)=\sum\limits_{k=k_0}^{\infty}a_{k}x^{k/n} \label{eq:formalLPS} \] with coefficients $a_{k}\in\C\;(k\in\Z)$ are important in many branches of mathematics. \Maple\ supports the computation of {\em truncated\/} series with its {\tt series} command, and through the {\tt powerseries} package infinite series are available. In the latter case, the series is represented as a table of coefficients that have already been determined together with a function for computing additional coefficients. This is known as {\em lazy evaluation\/}. But these tools fail, if one is interested in an explicit formula for the coefficients $a_k$. In this article we will describe the \Maple\ implementation of an algorithm presented in several papers of the second author which computes an {\em exact\/} formal power series of a given function. This procedure will enable the user to reproduce most of the results of the extensive bibliography on series. We will give an overview of the algorithm and then present some parts of it in more detail. This package is available through the \Maple-share library with the name {\tt FPS}. We flavor this procedure with the following example. %\begin{maple} \begin{verbatim}〉 FormalPowerSeries(sin(x), x=0);\end{verbatim} \begin{samepage} \begin{verbatim} infinity ----- k (2 k + 1) \ (-1) x ) ---------------- / (2 k + 1)! ----- k = 0 \end{verbatim} \end{samepage} }
    Keywords: ddc:000
    Language: English
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  • 38
    Publication Date: 2014-02-26
    Description: One of the challenging problems in the design of electronic circuits is the so-called routing problem. Roughly speaking, the task is to connect so-called terminal sets via wires on a predefined area. In addition, certain design rules are to be taken into account and an objective function such as the wiring length must be minimized. The routing problem in general is too complex to be solved in one step. Depending on the user's choice of decomposing the chip design problem into a hierarchy of stages, on the underlying technology, and on the given design rules, various subproblems arise. We discuss several variants of practically relevant routing problems and give a short overview on the underlying technologies and design rules. Many of the routing problems that come up this way can be formulated as the problem of packing so-called Steiner trees in certain graphs. We consider the Steiner tree packing problem from a polyhedral point of view and present three possibilities to define an appropriate polyhedron. Weighing their pros and cons we decide for one of these polytopes and sketch some of our investigations.
    Keywords: ddc:000
    Language: English
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  • 39
    Publication Date: 2014-02-26
    Description: We derive fast solvers for discrete elliptic variational inequalities of the second kind as resulting from the approximation by piecewise linear finite elements. Following the first part of this paper, monotone multigrid methods are considered as extended underrelaxations. Again, the coarse grid corrections are localized by suitable constraints, which in this case are fixed by fine grid smoothing. We consider the standard monotone multigrid method induced by the multilevel nodal basis and a truncated version. Global convergence results and asymptotic estimates for the convergence rates are given. The numerical results indicate a significant improvement in efficiency compared with previous multigrid approaches.
    Keywords: ddc:000
    Language: English
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  • 40
    Publication Date: 2014-02-26
    Description: The design of cost-efficient networks satisfying certain survivability constraints is of major concern to the telecommunications industry. In this paper we study a problem of extending the capacity of a network by discrete steps as cheaply as possible, such that the given traffic demand can be accommodated even when a single edge or node in the network fails. We derive valid and non-redundant inequalities for the polyhedron of capacity design variables, by exploiting its relationship to connectivity network design and knapsack-like subproblems. Computational work using this model and the additional inequalities is in progress.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 41
    Publication Date: 2014-02-26
    Description: In this paper, a rather recent algorithmic approac to the numerical simulation of macromolecula processes is surveyed. It avoids the numerical stiff integration o thousands up to millions of ODE's by constructing a scale of discret Hilbert spaces, especially weighted sequence spaces, and establishing corresponding Galerkin method. Examples including polyreactions o industrial relevance and ecological waste management by biochemica recycling illustrate the importance and efficiency of the algorithm.
    Keywords: ddc:000
    Language: English
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  • 42
    Publication Date: 2014-02-26
    Description: We show that, given a wheel with nonnegative edge lengths and pairs of terminals located on the wheel's outer cycle such that no two terminal pairs cross, then a path packing, i.~e.,a collection of edge disjoint paths connecting the given terminal pairs, of minimum length can be found in strongly polynomial time. Moreover, we exhibit for this case a system of linear inequalities that provides a complete and nonredundant description of the path packing polytope, which is the convex hull of all incidence vectors of path packings and their supersets.
    Keywords: ddc:000
    Language: English
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  • 43
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    Publication Date: 2019-10-24
    Keywords: ddc:000
    Language: German
    Type: annualzib , doc-type:report
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  • 44
    facet.materialart.
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    Publication Date: 2019-10-24
    Keywords: ddc:000
    Language: German
    Type: annualzib , doc-type:report
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  • 45
    Publication Date: 2022-07-07
    Description: The paper presents a construction scheme of deriving transparent , i. e. reflection-free, boundary conditions for the numerical solution of Fresnel's equation (being formally equivalent to Schrödinger's equation). These boundary conditions appear to be of a nonlocal Cauchy type. As it turns out, each kind of linear implicit discretization induces its own discrete transparent boundary conditions.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 46
    Publication Date: 2022-07-19
    Description: Sparse LU factorization offers some potential for parallelism, but at a level of very fine granularity. However, most current distributed memory MIMD architectures have too high communication latencies for exploiting all parallelism available. To cope with this, latencies must be avoided by coarsening the granularity and by message fusion. However, both techniques limit the concurrency, thereby reducing the scalability. In this paper, an implementation of a parallel LU decomposition algorithm for linear programming bases is presented for distributed memory parallel computers with noticable communication latencies. Several design decisions due to latencies, including data distribution and load balancing techniques, are discussed. An approximate performance model is set up for the algorithm, which allows to quantify the impact of latencies on its performance. Finally, experimental results for an Intel iPSC/860 parallel computer are reported and discussed.
    Keywords: ddc:000
    Language: English
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  • 47
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Analytical methods have been developed for the simultaneous quantitation of azelastine (AZ) and desmethylazelastine (DAZ) in guinea pig plasma and lung tissue. The methods require a 1.00 mL plasma sample and a minimum 0.100 g lung sample. Both methods employ liquid/liquid organic extraction and back-extraction into dilute acid. Quantitation is performed by high performance liquid chromatography on a 2X250 mm 5 μm HypersilTM CPS column using fluroescence detection. The linear quantitative ranges for AZ.HCI and DAZ.HBr in plasma are 0.156-160 ng/mL and 0.313-160 ng/mL, respectively. The linear quantitative ranges for AZ.HCI and DAZ.HBr in lung tissue are 0.039-20 μg/g for both.
    Additional Material: 2 Ill.
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  • 48
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A rapid, sensitive and simple to operate high performance liquid chromatographic method for the simultaneous determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in plasma is described. The drug and its metabolites were extracted from plasma using commercially available reversed phase octylsilane bonded silica columns (1 mL Bond Elut C8, 50 mg). Chromatographic separation of morphine and its metabolites was achieved using a mobile phase, consisting of 2 mM sodium dodecyl sulphate in 0.05% phosphoric acid:acetonitrile (71.5:28.5 by volume), at a flow-rate of 1.2 mL/min, in conjunction with a Waters Nova-Pak C18 column (300 × 3.9 mm). The analytical column was used in combination with a Guard-Pak module containing a Nova-Pak C18 Guard-Pak insert. Using fluorescence detection (excitation 245 nm, emission 335 nm), plasma levels in the region of 5-10 μg/L for the drug and its metabolites can be detected with only 200 μL of plasma. The method has been applied to studies of the disposition of morphine and its metabolites in premature neonates requiring mechanical ventilation who were receiving the drug intravenously; preliminary findings in patients at steady state are presented.
    Additional Material: 1 Ill.
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  • 49
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A multidimensional column chromatographic method involving electrochemical detection using a carbon fibre microelectrode flow cell was optimized and successfully applied to the simultaneous determination of salbutamol and terbutaline in plasma at overdose levels. This method performs, in a single step, an efficient extraction and clean-up of salbutamol and terbutaline from human plasma. The calibration graphs over three days were linear over the calibration range 20-100 ng/mL plasma with a limit of detection of 1 ng and 0.8 ng/mL plasma for salbutamol and terbutaline, respectively. The intra- and inter-assay coefficients of variation were less than 8% and the recoveries ranged from 94 to 96%. The accuracy of the assay, which was defined as the percentage difference between the mean concentration found and the theoretical concentration, was 7% or better. The proposed method combines the advantages of being simple, reproducible and selective in the presence of other sympathomimetic and commonly ingested drugs and is suitable for routine analyses to obtain valuable information about the clinical effects and treatment of overdose with these drugs. The whole procedure takes ca. 10 min and compares favorably with detection at a conventional glassy carbon electrode.
    Additional Material: 7 Ill.
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  • 50
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 181-183 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic method has been developed for the determination of rafoxanide and closantel in ovine plasma. Acetonitrile and chloroform were used for the extraction. The mean recoveries were 78.69% and 80.59% for rafoxanide and closantel, respectively. This method was applied to the characterization of rafoxanide plasma kinetics following oral administration of therapeutic doses to sheep.
    Additional Material: 2 Ill.
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  • 51
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The separation of reduced and oxidized glutathione at an absolute sensitivity of about 100 pg by micellar electrokinetic capillary chromatography without derivatization is described. The time required for the separation is less than 10 min (the time between two following injections is about 15 min). The separation is characterized by high efficiency and good reliability. A partition mechanism is responsible for the high resolution observed. The method was utilized for the analysis of commercial preparations of glutathione and a good agreement with the expected results was obtained; the oxidation of the commercial glutathione in solution was easily analysed.
    Additional Material: 8 Ill.
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  • 52
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 235-250 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Application of HPLC as a prime tool in the area of enantiomeric resolution has opened doors of success and varied interest. Use of chiral reagents either indirectly (as derivatization reagent) or directly (added to stationary or mobile phase) has led to achieve resolution of a wide range of compounds. Amino acids, being important molecules with simple structure and easy availability, have been extensively studied. A bibliographic survey on HPLC resolution of amino acids and derivatives along with a brief discussion on general methods of enantiomeric separation has been presented.
    Additional Material: 4 Tab.
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  • 53
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. ii 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 54
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 275-276 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: L- and D-Amino acids (Leu or Phe) were derivatized with fluorogenic reagents, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F), 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole (ABD-F) and 5-(N,N-dimethylamino)naphthalene-1-sulfonylchloride (DNS-Cl), and separated on a Pirkle type column, Sumichiral OA 2500 (S) ((S)-1-naphthylglycyl-3,5-dinitrophenylamide silica gel) with a mobile phase of 20 mM ammonium acetate in methanol. The fluorometric detection of the derivatives was made at 530 nm, 590 nm and 530 nm with excitation at 470 nm, 450 nm, 450 nm and 350 nm, respectively. The former three derivatives of the enantiomers were separated well from each other; The as for each NBD-, DBD- and ABD-derivative of L- and D-Leu were 1.10, 1.11 and 1.10, respectively. However, the DNS derivatives of L-and D-Leu were not separated (separation factor, α = 1.0). All NBD- and ABD-derivatives of L- and D-Phe were also well separated (αs were 1.18, 1.17 and 1.16, respectively), while DNS-L- and -D-Phe were barely separated (α = 1.04). These data suggest that the 2,1,3-benzoxadiazole (benzofurazan) moiety is very effective and preferable to the dimethylaminonaphthalene sulfonyl (DNS) structure for the separation of enantiomers of amino acids derivatized with benzofurazan reagents.No recemization of each enantiomer occurred during the derivatization reaction with NBD-F, DBD-F and ABD-F at pH 8.0 and 60°C for 2 min, at pH 9.3 and 60°C for 30 min and pH 9.3 and 60°C for 60 min, respectively, meaning that all benzofurazan type fluorogenic reagents are useful for sensitive determination of amino acid enantiomers.
    Additional Material: 1 Ill.
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  • 55
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This report details a very sensitive, rapid and accurate ion-pair HPLC-ECD method for the analysis of biogenic amines and their metabolites in brain tissue. The method described enables detection of picogram amounts of 3-methoxy-4-hydroxy phenethyleneglycol (MHPG) (37 pg), 3,4-dihydroxy phenylacetic acid (DOPAC) (18 pg), norepinephrine (NE) (12 pg), epinephrine (E) (6 pg), 5-hydroxyindoleacetic acid (5-HIAA) (18 pg), 3,4-dihydroxyphenylethylamine (DA) (6 pg), 3-methoxy-4-hydroxyphenylacetic acid (HVA) (12 pg) and 5-hydroxytryptamine (5-HT) (12 pg). The linearity of the method is from 18.75 ng/mL to 300 ng/mL for MHPG; 9.37 to 150 ng/mL for DOPAC and 5-HIAA; 6.25 to 100 ng/mL for NE, HVA and 5-HT; and from 3.12 to 100 ng/mL for E and DA. The reproducibility, expressed as coefficient of variance (CV%) within-run and between-run groups, was 2.25% and 19.49% for MHPG; 3.84% and 29.84% for DOPAC; 0.89% and 8.97% for NE; 1.26% and 5.61% for E; 1.07% and 28.77% for 5-HIAA; 2.65% and 10.65% for DA; 5.97% and 24.38% for HVA; and 4.44% and 9.45% for 5-HT.
    Additional Material: 1 Ill.
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  • 56
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A procedure for the extraction and high performance liquid chromatographic (HPLC) determination of the photodynamic therapeutic agent 5,10,15,20-tetra(m-hydroxyphenyl)chlorin in human, rat and mouse tissues following intravenous administration of the drug is described. The tissue (tumour, skin, muscle and liver) was homogenized and extracted into a mixture of methanol:dimethyl sulphoxide:water (32:8:1 by vol.) containing, 5,10,15,20-tetra(p-hydroxyphenyl)chlorin as the internal standard. The precipitated proteins were removed by centrifugation and the supernatant was separated by reversed phase HPLC on a Hypersil-ODS column with 77% (v/v) acetonitrile in 0.1% trifluoroacetic acid as the mobile phase. The solute was detected with high sensitivity and specificity by a UV-VIS detector set at 423 nm.
    Additional Material: 2 Ill.
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  • 57
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 179-179 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 58
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Some L- and D-amino acids (Phe or Leu) were derivatized with a fluorogenic reagent, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) and separated on a Pirkle-type column, Sumichiral OA 2500(S) [(S)-1-naphthylglycyl-3,5-dinitrophenylamide silica gel] with a mobile phase of 20 mM ammonium acetate in methanol. The fluorometric detection was made at 530 nm with excitation at 470 nm. No racemization of the enantiomers occurred during the derivatization reaction. The separation factors (α) for NBD-L-Phe and NBD-D-Phe, and NBD-L-Leu and NBD-D-Leu, were 1.27 and 1.17, respectively. The detection limits were in the range of ca. 30 fmol.
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  • 59
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993) 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 60
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 189-195 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A reversed phase high performance liquid chromatographic technique is presented allowing purine catabolite determination in a whole blood extract without a prior purification step. The method was applied to determine the timing and the profile of myocardial nucleotide catabolite release during reperfusion of the transplanted human heart. Samples of arterial and coronary sinus blood collected at various times within 1 h after aortic declamping during heart or heart-lung transplantations were used for nucleotide catabolite determination. Massive release of inosine and hypoxanthine from the heart was demonstrated. Production of adenosine was also shown but there was no liberation of xanthine or uric acid. Nucleotide catabolite release was greatest in the first 5 min (coronary sinus-arterial difference = 15-20 μM), but was still significant after 30 min of reperfusion. The determination of inosine and hypoxanthine--major catabolites released--was found to be reproducible in coronary sinus blood (coefficient of variation 〈 10%). However, immediate protein precipitation afer blood sample collection was necessary, as rapid metabolism of both exogenous and endogenous adenosine and inosine was demonstrated.
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  • 61
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic method with chemiluminescence detection for the determination of penicillin G and ampicillin is reported. The method is based on the enhancement of the luminol chemiluminescence with β-lactam antibiotics. The linear relationship was obtained between the peak height and the concentration of penicillin G or ampicillin up to 15 nmol per 20 μL injection. Detection limits were 1 nmol for penicillin G and 0.5 nmol for ampicillin with a signal-to-noise ratio of 2. Relative standard deviations for five replicate measurements of 4 nmol/injection each of penicillin G and ampicillin were 2.1 and 2.3%, respectively.
    Additional Material: 6 Ill.
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  • 62
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 231-232 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 63
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993) 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 64
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 65-88 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Most avian muscles consist of serially arranged, overlapping fibers that do not extend the length of the muscle. This condition appears to be plesiomorphic with respect to diapsid reptiles. The presence of this serialfibered architecture is evidenced by bands of stained motor end-plates (meps) perpendicular to the columns of fibers and dividing each column into a series of “segments.” The avian pectoralis was chosen for a study of variation in the distribution of meps within a single muscle. We report the interspecific variation for 158 specimens in 63 species. We also use additional specimens to examine intraspecific variation.Setting aside hummingbirds, which have an unique and clearly derived condition, the number of mep bands along a column of fibers near the shoulder falls within a remarkably small range. The number of segments is not obviously related to phylogenetic relatedness or to any characteristic of flight or ecology and is only slightly related to size. The largest specimens do average more segments per column, but there are no trends among small to medium-sized species, suggesting that there is an upper limit to fiber length. However, the shape of the sternum and pattern of connective tissue in the pectoralis alleviate the need for additional fibers in many large birds. These findings suggest that the architecture of the avian pectoralis is subject to some as yet unexplained selection that stabilizes the number of myofibers and/or motor neurons. The findings provide few clues as to whether the significant factors are phylogenetic, functional, ontogenetic, or some combination of these. © 1993 Wiley-Liss, Inc.
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  • 65
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    Journal of Morphology 215 (1993) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 66
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    Journal of Morphology 215 (1993), S. 101-118 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tetraodontiform fishes are characterized by jaws specialized for powerful biting and a diet dominated by hard-shelled prey. Strong biting by the oral jaws is an unusual feature among teleosts. We present a functional morphological analysis of the feeding mechanism of a representative tetraodontiform, Balistes vetula. As is typical for the order, long, sharp, strong teeth are mounted on the short, robust jaw bones of B. vetula. The neurocranium and suspensorium are enlarged and strengthened to serve as sites of attachment for the greatly hypertrophied adductor mandibulae muscles. Electromyographic recordings made from 11 cranial muscles during feeding revealed four distinct behaviors in the feeding repertoire of B. vetula. Suction is used effectively to capture soft prey and is associated with a motor pattern similar to that reported for many other teleosts. However, when feeding on hard prey, B. vetula directly bit the prey, exhibiting a motor pattern very different from that of suction feeding. During buccal manipulation, repeated cycles of jaw opening and closing (biting) were coupled with rapid movement of the prey in and out of the mouth. Muscle activity during buccal manipulation was similar to that seen during bite-captures. A blowing behavior was periodically employed during prey handling, as prey were forcefully “spit out” from the mouth, either to reposition them or to separate unwanted material from flesh. The motor pattern used during blowing was distinct from similar behaviors described for other fishes, indicating that this behaviors may be unique to tetraodontiforms. Thus B. vetula combines primitive behaviors and motor patterns (suction feeding and buccal manipulation) with specialized morphology (strong teeth, robust jaws, and hypertrophied adductor muscles) and a novel behavior (blowing) to exploit armored prey such as sea urchins molluscs, and crabs. © 1993 Wiley-Liss, Inc.
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  • 67
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    Journal of Morphology 215 (1993), S. 165-182 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the early chick embryo was investigated, using scanning (SEM) and transmission electron microscopy (TEM). Eggs were obtained from the shell gland by injecting hens intravenously with a synthetic prostaglandin or arginine vasopressin. Embryos were examined during late cleavage (stages IV-VI, Eyal-Giladi and Kochav, '76), formation of the area pellucida (stages VII-XI), and formation of the hypoblast (stages X-XIV). SEM highlighted the reduction in cell number at the underside of the embryo during formation of the area pellucida although it became apparent that the thickness of the embryo is not reduced to a single layer of cells at stage X. In addition, blastomeres at the perimeter of embryos (stages V-VI) project filopodial extensions onto a smooth membrane that separates the sub-embryonic cavity from the yolk. During hypoblast formation, epiblast cells generate stellate projections at their basal aspect, thus providing a meshwork for the advancing secondary hypoblast cells. By stage XII the epiblast was one cell thick and reminiscent of a columnar epithelium when viewed transversely. Cells of the deep portion of the posterior marginal zone were distinguished morphologically in the stage XII embryo by their many cell surface projections and ruffled appearance. Blastomeres at the perimeter of stage V-VI embryos projected filopodial extensions onto a smooth membrane which separates the sub-embryonic cavity from the yolk. This membrane is presumed to be confluent with the cytolemma. Evidence is presented demonstrating the presence of intracellular membrane-bound droplets which are hypothesised to contain sub-embryonic fluid. © 1993 Wiley-Liss, Inc.
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  • 68
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    Journal of Morphology 215 (1993), S. 245-260 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The highly terrestrial grapsids and gecarcinids and the amphibious sundathelphusids all have large, expanded branchial chambers. The lining of the branchial chambers is smooth and well vascularized, and it functions as a lung. The respiratory membrane and the cuticle lining the lung are extremely thin (200-350 nm). The blood vessels within the lung are formed from connective tissue cells supported by collagen fibres and lined by a basal lamina. The major vessels in the lung are embedded deep in the branchiostegite and lie just beneath the thick outer carapace. These vessels branch towards the respiratory membrane, where they eventually lose their connective tissue coverings to form thin, flattened lacunae directly below the respiratory epithelium. The lacunae (exchange sites) are bordered by specialized connective tissue cells, which either bear microvilli on their apical surface (fimbriated cells) or are very smooth. The respiratory circulation in the lung is very complex, with two portal systems present between the afferent and efferent systems, producing a total of three lacunal exchange beds. Portal systems increase the surface area available for gas exchange. The major distributing vessel in the lung is the branchiostegal vein, which runs along the inner margin of the branchiostegite. The main venous supplies come anteriorly from the infraorbital and ventral sinuses and posteriorly from the procardial sinus. The main collecting vessel is the pulmonary vein, which arises anteriorly and which runs around the ventral perimeter of the branchiostegite before emptying into the pericardial sinus. © 1993 Wiley-Liss, Inc.
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  • 69
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    Journal of Morphology 215 (1993), S. 301-312 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Annual fish development differs from that of other teleosts because a phase of blastomere dispersion-reaggregation spatially and temporally separates epiboly from embryogenesis. The fate of dispersed blastomeres was assessed in diblastodermic eggs of the annual fishes Cynolebias whitei and C. nigripinnis. In typical teleosts, blastomere determination and the events of primary embryonic induction occur prior to or during epiboly, so diblastodermic eggs produce partially or completely duplicated embryos. In the diblastodermic eggs of Cynolebias, the two blastoderms are completely separate from the one cell stage to the high blastula. Blastoderm fusion begins during midepiboly. By the end of epiboly, blastoderm fusion has been completed, and the deep, embryo-forming blastomeres of both blastoderms have completely dispersed and intermingled to form a single cell population. A typical annual fish dispersed blastomere phase ensues. Blastomeres reaggregate into a single mass, in which one embryo develops. When hatched, the young fish have no obvious structural or functional abnormalities. We suggest that the dispersed blastomeres of annual fish eggs are equivalent and that induction or determination takes place within the reaggregate. Alternatively, dispersed cells are partially determined but highly regulative, so that, when two populations fuse, the cells sort out according to tissue type and form a single embryo. In either instance, the formation of a single, normal embryo seems to corroborate the hypothesis that the dispersed cell phase of annual fishes is an adaptation that prevents environmentally induced developmental defects. © 1993 Wiley-Liss, Inc.
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  • 70
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    Journal of Morphology 217 (1993), S. 171-181 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the American alligator, the jaw muscles show seven bundles of tendinous structure: cranial adductor tendon, mandibular adductor tendon, lamina anterior inferior, trap-shaped lamina lateralis, lamina intramandibularis, lamina posterior, and depressor mandibular tendon (originating from the musculus depressor mandibulae, m. pseudotemporalis, m. adductor mandibulae posterior, m. adductor mandibulae externus, m. intramandibularis, m. pterygoideus anterior, and m. pterygoideus posterior). These tendinous structures are composed of many collagen fibrils and elastic fibers; however, the distributions and sizes of the fibers in these tendinous components differ in comparison with those of other masticatory muscles. The differences of these properties reflect the kinetic forces or the stretch applied to each tendon by the muscle during jaw movements in spite of the simple tendon-muscle junctions. © 1993 Wiley-Liss, Inc.
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  • 71
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe the complex shapes of myomeres and myosepta in the mackerels and tunas (Scombridae: Teleostei), and we reveal the orientation of two major systems of collagen fibers in myosepta and horizontal septa with respect to points of attachment to skeleton and skin. Our goal is to identify the likely pathways of the transmission of muscle forces during locomotion. Our primary conclusions are (1) that the collagen fibers of myosepta, horizontal septa, and skin are the organs that transfer locomotor forces from the contraction of myomeres to the backbone and caudal fin during locomotion, and (2) that locomotor muscle pulls against a three-dimensional structure of tendons, septa, and skin that is kept in tension by the radial expansion of the contracting muscle. The main horizontal septum is formed by the convergence of myosepta and is likely to be the major transmitter of muscle force to the axial skeleton. The geometry of the myomeres, the position of red muscle, and particularly the geometric conformation of crossed-fiber arrays of collagen in the main horizontal septum suggest specific mechanisms for the transfer of muscle force to the backbone among scombrid fishes. Morphometrics and the construction of physical models help us to identify musculoskeletal mechanisms of locomotion, and we present two quantitative models of locomotor mechanics in fishes. © 1993 Wiley-Liss, Inc.
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  • 72
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    Journal of Morphology 217 (1993), S. 205-217 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Despite a great deal of work in recent years on the structure of reptilian eggshells, few studies have examined the structure and regulation of the female reproductive tract in the formation of eggshell components, and none have examined the entire process from ovulation to oviposition. In this study, we examined oviductal structure in the oviparous lizard, Sceloporus woodi, followed changes in oviductal structure during gravidity, and determined uterine function in the formation of eggshell components. The endometrial glands of the uterus produce the proteinaceous fibers of the eggshell membrane mainly during the first 24 hours following ovulation, and the fibers are secreted intact and subsequently wrapped around the in utero eggs. Eggshell fibers of different thicknesses are layered around each egg, ranging from an inner layer of thick fibers that gradually become thinner medially and finally forms an outer layer of densely packed particulate matter. These changes in the fibrous layer are reflected by the thickness and length of fibers released from the endometrial glands. Calcium deposition occurs from 3 days following ovulation through day 14 (oviposition) and is accompanied by cellular changes in the luminal epithelium suggestive of secretory activity. Deposition of the eggshell components within the uterus occurs on all eggs simultaneously, rather than sequentially. © 1993 Wiley-Liss, Inc.
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  • 73
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    Journal of Morphology 217 (1993), S. 219-227 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphogenesis of glandular architecture of the three lobes of prostate gland of the guinea pig, lateral, dorsal, and coagulating gland was studied from 35 days gestation to 90 postnatal days. Epithelial ductal tubules of various lobes of the gland were microdissected after treatment by collagenase and displayed two dimensionally. The number of ductal tips was counted, and the volume of the ductal network was quantified using a graphic tablet. The results show that the growth and ductal morphogenesis fall into two phases: prenatal and postnatal. The first outgrowth of prostatic buds begins at 35 days gestation (gestational length is 65 days). Ductal growth and branching continues over the next 15-20 days and by 55 days gestation, approximately 60%, 79%, and 71% of the adult number of ductal tips of the lateral and dorsal lobes and coagulating gland respectively, are formed. The figures increase to 89%, 84%, and 106%, respectively, by birth. There is little increase in number of ductal tips thereafter. Postnatal growth is accomplished mainly by elongation of existing ductal network with a little additional branching but with an increase in size (volume) of the tubules. Canalization of ductal tubules occurs prenatally in all lobes but postnatal functional cytodifferentiation takes a slightly different pace among them. Ductal morphogenesis of the guinea pig prostate gland differs significantly in time-course from that of the mouse in which ductal development occurs mainly postnatally. © 1993 Wiley-Liss, Inc.
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  • 74
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    Journal of Morphology 217 (1993) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 75
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    Journal of Morphology 217 (1993), S. 229-238 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure and tooth attachment of the comblike teeth and denticles of the ayu sweetfish, Plecoglossus altivelis, were examined by light and scanning electron microscopy. The denticle is composed of a spoonlike crown with a spine pointed anteriorly, a triangular plate in the cervical region, and a root that curves laterally and tapers off to a point. The root apex is fused with a long thin pedicle that turns abruptly anteriad toward the jaw bone. Planes of the spine, the spoonlike crown, the triangle plate and the root of the denticle are varied, and the denticle is twisted in the region of the triangle plane.The superficial layer of the dentine is homogeneously calcified and is considered to be enameloid, because some of the inner dentinal epithelial cells in the tooth germ are columnar and possess cellular processes at their apical ends. The dentine is fibrous and fine dentinal tubules are visible in dentine treated with sodium hydroxide and observed by scanning electron microscopy. The upper half of the root is surrounded by a dense layer of collagen fibers running parallel to the tooth axis, and the lower half is encompassed by interlaced collagen fibers. The lower part of the root is open on its lingual side. The pedicle is a long rod which is homogeneously calcified and enmeshed by interlaced collagen fibers, and it curves mediad as it nears the jaw bone. The pedicles are interposed between a layer of gelatinous connective tissue and the jaw bone and terminate on the periosteum. Comparative aspects of ayu tooth morphology are discussed. © 1993 Wiley-Liss, Inc.
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  • 76
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    Journal of Morphology 217 (1993), S. 239-261 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Under the influence of juvenile hormone analogues (JHAs), termite workers are induced to differentiate into soldiers. In Reticulitermes santonensis, such induced differentiation is often incomplete, resulting in intercaste production. The morphology of the structures most affected during differentiation was analyzed descriptively and biometrically in normal workers, presoldiers, and soldiers, and in experimental intercastes. We observed that intercastes form a morphological and biometrical continuum between workers and presoldiers (presoldier intercastes), and between presoldiers and soldiers (soldier intercastes). We also compared the biochemistry of the normal individuals and of the intercastes; in contrast to workers, the intercastes possess a frontal gland secretion which differs from those of the presoldiers and soldiers. Besides intercaste characterization, we consider the mode of action of JHAs in termite differentiation. © 1993 Wiley-Liss, Inc.
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  • 77
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    Journal of Morphology 217 (1993), S. 263-271 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtopographic features of the various growth stages of the three free-living larval stages of the rat hookworm Nippostrongylus brasiliensis (Nematoda) were surveyed by scanning electron microscopy. These worms have a rounded anterior end and an elongated tail. Cuticular annulations were observed along the body, which also bore two ribbon-like lateral alae. Two rings of six lip-like lappets were observed around the triradiate oral opening in all larval stages. The cephalic space contained two lateral amphidial pits. The excretory pore in the third anterior part was observed in a ventral view of the larvae. No deirids were observed. The anus with a crescent-shape opening was located posteriorly. Phasmidial apertures, only observed in the third-stage larvae, opened on the lateral alae in the tail region. © 1993 Wiley-Liss, Inc.
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  • 78
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    Journal of Morphology 218 (1993), S. 347-358 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatogenesis discontinues during both adult reproductive diapause and quiescence in the flightless males of Omorgus freyi. During both types of dormancy, spermatogenesis discontinuity is a dynamic process involving an uninterrupted supply of primary spermatocytes that undergoes partial development and lyses before spermatozoa can be formed. Notwithstanding this common feature, the pattern of discontinuity differs between the two kinds of dormancy. During reproductive diapause, spermatozoa and late spermatids are the first cells that lyse; after diapause break, spermatozoa are produced anew. During quiescence, in contrast, the first indication of discontinuity is the degeneration of late primary spermatocytes; spermatozoa apparently remain intact for a while but eventually degenerate as well. Therefore, males returning to sexual activity after a short period of quiescence may still have spermatozoa capable of fertilization. However, following a long period of quiescence, spermatozoa will be absent and must be produced anew, as in postdiapausing males. The existence of two different patterns of spermatogenesis discontinuity may indicate that each is controlled differently by the endocrine system, in response to the different environmental conditions inducing quiescence or diapause. Dual control of discontinuity may contribute to the high reproductive potential of these flightless beetles, under unpredictable and extreme desert conditions. © 1993 Wiley-Liss, Inc.
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  • 79
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    Biomedical Chromatography 7 (1993), S. 48-55 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have investigated the hydrophobic properties of human skin fibroblast proteoglycans and related material by affinity chromatography on Octyl-Sepharose CL-4B in 4 M guanidinium hydrochloride (GdnHCI). Proteoglycans and related material could be separated into non-, medium and highly hydrophobic forms by elution with gradients of Triton X-100 in 4 M Gdn HCI. The non-hydrophobic material included endogenously produced glycosaminoglycan chains and oligosaccharides as well as an HS-proteoglycan with a 35 kDa core. The 65-70 kDa core (glypican-related) proteoglycans appeared among the highly hydrophobic ones, but variable proportions were seen both in the medium and the non-hydrophobic material. Other membrane-bound proteoglycans, like fibroglycan (45 kDa core) and the HS-proteoglycans with 90 and 130 kDa cores, as well as the CS/DS-proteoglycan with a 90 kDa core, were all of high hydrophobicity. There were also indications of a highly hydrophobic CS/DS-proteoglycan with a 45 kDa core. The extracellular proteoglycans, PG-L, PG-S1 and PG-S2, and the HS-proteoglycans with 350 and 250 kDa cores were all of medium hydrophobicity. These proteoglycans emerged in distinct positions when the column was eluted with a gradient of 3-[(3-cholamidopropyl)dimethylammonio]propanesulphonate.
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  • 80
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The reactivities between saccharides and primary amino compounds were studied by liquid chromatography on an amino-bonded column and by measurement of the reaction rates of aromatic amines with saccharides. The recoveries from the column and the reaction rates were correlated with their physicochemical properties calculated by the CACheTM program. The reactivities between amines and saccharides correlated well with their hydrogen bonding energies calculated by molecular mechanics.
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  • 81
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    Biomedical Chromatography 7 (1993), S. 86-89 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A rapid, sensitive and selective method for the assay of glutathione in cultured cells has been developed using ion-pair reversed phase rapid high performance liquid chromatography. The use of a 4 μm particle, 5 cm long column (Superspher 100 RP 18 end-capped) allowed complete analysis of glutathione within 3 min. A postcolumn derivatization reaction with o-phthaladehyde and fluorometric detection made the assay fully selective with regard to other endogenous thiols and sensitive (the detection limit was 0.5 ng of glutathione injected). The linearity range was between 0.1 and 2.0 μg/mL with good repeatability (relative standard deviation less than 5% for the lowest concentration quantitated). Recoveries of GSH from cultured cell samples were above 98%. The rapid analysis enabled the processing of a large number of samples in a short time (up to 20 per hour). The method was applied to the measurement of the intracellular glutathione amount in V79 fibroblasts along cell growth in culture.
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  • 82
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A stereoselective and sensitive method for the determination of the enantiomers of felodipine, a dihydropyridine calcium antagonist, has been developed and the pharmacokinetic profiles of the enantiomers comparatively studied after oral administration to dogs and humans. D6-Felodipine, the internal standard, was added to the plasma, extracted with a solvent and then optically resolved into S(-) and R(+) enantiomers on a high performance liquid chromatographic Chiralcel OJ column. Each enantiomer in the effluent was analysed by capillary column gas chromatography/positive ion electron impact mass spectrometry. After oral administration of the felodipine racemate, the Tmax and t1/2 values hardly differed between the two enantiomers in dogs and humans. The Cmax and AUC0-24h values of the S(-) enantiomer were slightly higher than those of the R(+) enantiomer in humans but the difference between the enantiomers was not significant. These results suggested that there is no large difference in the absorption, distribution and elimination of felodipine enantiomers after oral administration of the racemate in either dog or human.
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  • 83
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The development of column packing materials was tried as a contribution to studies related to the further modification of 3-aminopropyl-modified silica gel. Consequently, we prepared two types of gel, 3-(1-naphthoylamino)- and 3-(1-anthroylamino)-propyl-modified silica gels (NAPS and AAPS). Since NAPS and AAPS, each having an aromatic ring, were expected to behave in a separation mode by a π-π or hydrophobic interaction, their application to the analyses of the compounds related to nucleic acids was carried out. Adenosine nucleotides were consequently separated by the gels in a single analysis by a single buffer elution with UV detection. NAPS could be also successfully used for the measurement of ATPase activity in fish meat (Sillago japonica). The mobile phase consistently used in the analysis was an aqueous phosphate buffer.
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  • 84
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A selective and sensitive method has been developed for the determination of secondary amines by gas chromatography (GC). After removal of primary amines by the reaction with o-phthaldialdehyde, secondary amines were converted into their N-diethylthiophosphoryl derivatives and then measured by GC with flame photometric detection using a DB-1701 capillary column. The derivatives were sufficiently volatile and stable to give single symmetrical peaks. The detection limits of secondary amines were ca. 0.05-0.2 pmol per injection. N-Methylcyclohexylamine was used as an internal standard. The calibration curves for secondary amines in the range 1-20 nmol were linear and sufficiently reproducible for quantitative determination. This method was successfully applied to small urine samples without prior clean-up. Overall recoveries of secondary amines added to urine samples were 91-105%. By using this method, secondary amines in urine samples could be analysed without any influence from primary amines and other coexisting substances. The analytical results of secondary amine content in urine samples of normal subjects are presented.
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  • 85
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method has been developed for the quantitative analysis of clomipramine and its major metabolite desmethylclomipramine in plasma, using normal phase chromatography with UV detection at 254 nm. This rapid (6 min) and highly sensitive methodology (detection limits 0.5 ng/mL and 2 ng/mL for clomipramine and desmethylclomipramine, respectively; S/N = 3, 0.001 aufs) allows pharmacokinetic studies and drug monitoring of the two compounds. Using the described methodology we report an application which involved 10 depressed inpatients.
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  • 86
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A simple, selective, reversed phase liquid chromatographic method using a column-switching technique has been developed for the simultaneous determination of a novel derivative of etoposide (NK611) and its O-demethyl metabolite in dog plasma. A good linear response was obtained for both drugs in the range 0.1-12.0 μg/mL. The mean recoveries were within 100±5%. The within- and between-day precisions were within 3.5% and 4.6%, respectively. This method was used in a pharmacokinetic study following intravenous and oral administration of NK611 to beagle dogs.
    Additional Material: 6 Ill.
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  • 87
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    Biomedical Chromatography 7 (1993), S. 94-98 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Two forms of liver metallothioneins (MTs) were purified from hedgehog exposed to zinc, using gel filtration on Sephacryl S-100 and DEAE Sepharose Fast Flow chromatography. The peptide chain weight of both MT-1 and MT-2 was found to be about 10,000, as determined by high performance liquid chromatography. This value was higher than that calculated from amino acid analysis. The amino acid composition of hedgehog liver MT-1 and MT-2 resembles that of liver to MTs from rabbit and other species. Their distinctive features include an extremely high cysteine content, about 33% of all the amino acid residues, and an absence of aromatic amino acids and histidine. In addition, a rapid method for the determination of MTs during animal tissue purification has been established. The samples were directly added in an ammoniacal solution of a Co(II) salt for recording linear sweep polarograms. By comparison with the commonly used metal determination method, our method is direct, rapid, credible and suitable for all the MTs or MT-like samples.
    Additional Material: 6 Ill.
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  • 88
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A reversed phase high performance liquid chromatographic method for the high sensitivity determination of individual bile acids in serum using a C18 column with a ternary solvent system combined with fluorometric techniques using immobilized enzymes is described. A computer-assisted diagnosis system using pattern recognition was developed to assist the clinical diagnosis of various liver and biliary diseases. A total consistency rate of 95% can be reached using this system.
    Additional Material: 3 Ill.
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  • 89
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 143-145 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Human pancreatic carboxypeptidase A, which was isolated from a pool of necrobiotic pancreae, crystallized spontaneously and appeared homogeneous in sodium dodecylsulphate polyacrylamide gel electrophoresis. Reversed phase high performance liquid chromatography of the dissolved crystals, however, revealed the presence of two distinct isoenzymes, which were shown by aminoterminal sequence analysis to be only 61% homologeous in their 31 amino terminal amino acids. On the other hand, amino terminal sequences of the isoenzymes were found to be 79% and 87% homologeous with CAP 1 and CPA 2 of the rat, respectively. Thus, the presence of two distinct pancreatic carboxypeptidase A isoenzymes could be clearly demonstrated for the first time in human tissue.
    Additional Material: 2 Ill.
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  • 90
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 200-203 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Formation of free radicals and lipoperoxidation occur at the onset of cellular damage. These effects are produced during normal metabolism and in pathological states. The peroxidation of polyunsaturated fatty acids, i.e. linoleic acid and linolenic acid, which are both cellular membrane compounds, induces ethane and pentane formation in pulmonary air exhalation. These two volatile hydrocarbons can be considered as potential lipoperoxidation markers. Methodological difficulties limit the use of these gases for assessment of free oxygen radical activity but we have developed and validated a non-invasive technique. A study was performed with ten healthy volunteers.
    Additional Material: 3 Ill.
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  • 91
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A gas chromatographic method for the determination of mexiletine in human plasma is described. Mexiletine was simultaneously extracted and derivatized with carbon disulphide for separation and quantitation on a glass column (1.5 m × 3 mm i.d.) packed with 1.5% OV-1 coated on 80-100 mesh Shimalite W (201D). The method required only 0.5 mL of plasma and could detect as little as 10 ng of mexiletine. It has been applied to the study of the pharmacokinetics of mexiletine in healthy volunteers.
    Additional Material: 5 Ill.
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  • 92
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Fluorescence and chemiluminescence analyses of amino acids and thiols derivatized with 2-fluoro-4,5-diphenyloxazole (DIFOX) and 2-chloro-4,5-bis(p-N,N-dimethylaminosulphonylphenyl)oxazole (SAOX-CI) were investigated. Thirteen diphenyloxazole (DIOX)-derivatized amino acids were separated within 38 min by a linear gradient elution from 100% A [0.05 M phosphate (pH 7.0):CH3CN (75:25)] to 100% B [0.05 M phosphate (pH 7.0):CH3CN (1:1)] over 30 min and an isocratic elution of 100% B for 30 min. The detection limits (S/N = 2) with fluorescence detection were in the range of 19-64 fmol. Thiols derivatized with SAOX-CI were separated by an isocratic elution using 0.1 M H3PO4:CH3CN (65:35) and detected fluorimetrically. The detection limits (S/N = 2) of reduced glutathione, N-acetylcysteine, 2-mercaptopropionylglycine, cysteine, homocysteine and captopril were 1.2, 1.5, 1.9, 5.7, 6.4 and 7.9 fmol, respectively. Peroxyoxalate chemiluminescence (CL) intensities of sulphonyl-5-N,N-dimethylaminonaphthalene (DNS), SAOX and DIOX derivatives were compared using three different oxalate esters (DFPO, TCPO and TDPO) by flow injection analysis. The relative chemiluminescence intensity (RCL) of SAOX-proline and DIOX-proline were 76-80% and 19-25% of DNS-proline (100%), respectively. Other SAOX and DIOX derivatives showed lower CL intensities ( 〈 12%). Extremely low CL intensities were obtained for the fluorescent tagging reagents (〈0.11%) and their hydrolysis products (〈0.80%). Secondary amino acids and peptides, derivatized with DIFOX in aqueous media at room temperature for 1 h, were detected using DFPO/H2O2. TCPO/H2O2 and TDPO/H2O2 after separation by high performance liquid chromatography. The detection limits (S/N = 2) of hydroxy-L-proline, L-proline, L-prolyl-glycyl-glycine and L-prolyl-L-leucine with the three oxalate esters were 10-17 fmol, 22-34 fmol, 50-61 fmol and 80-123 fmol, respectively.
    Additional Material: 10 Ill.
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  • 93
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. ii 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 94
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 229-230 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A sensitive and selective reversed phase high performance liquid chromatographic method was introduced for the determination of salmon calcitonin (sCT) in solutions containing bovine serum albumin or gelatin. The method was based on the sensitive fluorescence detection of sCT by postcolumn derivatization with o-phthal(di)aldehyde. The sample was loaded onto a reversed phase column, purified by column switching and separated with linear gradient elution using the ion pair technique. A linear relationship was obtained between the peak height and the amount injected in the concentration range 1-40 ng. The detection limit was 10 ng/mL (S/N = 3) at a sample injection volume of 100 μL.
    Additional Material: 1 Ill.
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  • 95
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 256-261 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Amyloglucosidase from Halobacterium sodomense was purified by a combination of hydrophobic interaction chromatography and immobilized metal ion affinity chromatography at analytical and preparative scale with 75% recovery. The enzyme was found to be a dimer of two different subunits with molecular weights of 72,000 and 82,000 D, respectively, combining in a 175,000 D native protein. The specific activity, KM, and amino acid composition of the enzyme was determined.
    Additional Material: 6 Ill.
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  • 96
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 273-274 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A sensitive (up to nanogram level) method for resolving a cannabinoid mixture in plasma is described. Cannabinoids were extracted with a C-18 Sep Pak cartridge and derivatized with dansylchloride. Then the derivatives were resolved on thin layer HPTLC silica plates which were developed and quantified by fluorescence densitometry at 340 nm.
    Additional Material: 2 Ill.
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  • 97
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The recent developments in enantioselective HPLC-separation techniques are impressive and are driven by industrial and academic interests; thus there is for instance a high demand for developing stereoselective assays for chiral drugs in biological fluids. The beta-blocking agents, which possess an amino- propanol- or -ethanol side chain with at least one chiral centre, represent one of the most intensively investigated groups of more than 40 drugs introduced world wide. Seven of the most popular beta-blockers were chosen as representatives: atenolol; betaxolol; carvedilol; metoprolol; pindolol; propranolol; and sotalol, these span the whole range of lipophilicity to hydrophilicity (polarity). Enantioselective HPLC bioassays for these β-blockers published so far, including techniques based on chiral derivatizing agents (CDAs), chiral stationary phases (CSPs) and chiral mobile phase additives (CMPAs) have been reviewed and documented in the light of general aspects together with pharmacokinetic and pharmacodynamic considerations.
    Additional Material: 8 Ill.
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  • 98
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. ii 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 99
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 227-228 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic (HPLC) method has been developed for the determination of levomepromazine in human breast milk and serum. The levomepromazine was extracted by a rapid and simple extraction method using a Sep-Pak C18 cartridge. The extracts were separated by HPLC on a C8 bonded reversed phase column and detected by UV absorbance at 254 nm. There was no interference with endogenous substance in human breast milk and serum. A linear relationship was obtained for the levomepromazine over the concentration range of 10-300 ng/mL. The recoveries of levomepromazine added to human breast milk and serum were 92.5-99.1% and 86.9-103.9%, respectively.
    Additional Material: 1 Ill.
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  • 100
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    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 233-233 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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