Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 2010-2014
  • 2005-2009  (53)
  • 1980-1984
  • 1975-1979  (3.937)
  • 1920-1924
  • 1910-1914
  • 2006  (53)
  • 1976  (3.937)
  • Polymer and Materials Science  (2.626)
  • Inorganic Chemistry  (739)
  • Life and Medical Sciences  (572)
  • Cell & Developmental Biology  (502)
  • ddc:000
  • ddc:004
  • ddc:020
  • ddc:510
Datenquelle
Materialart
Erscheinungszeitraum
  • 2010-2014
  • 2005-2009  (53)
  • 1980-1984
  • 1975-1979  (3.937)
  • 1920-1924
    • +
Jahr
Schlagwörter
Sprache
  • 1
    facet.materialart.
    Unbekannt
    Jahresbericht 2005 (2006)
    Details
    Publikationsdatum: 2019-10-24
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: annualzib , doc-type:report
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 2
    facet.materialart.
    Unbekannt
    Convergence of the Control Reduced Interior Point Method for PDE Constrained Optimal Control with State Constraints (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We propose a variant of the control reduced interior point method for the solution of state constrained problems. We show convergence of the corresponding interior point pathfollowing algorithm in function space. Morever, we provide error bounds for the iterates.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 3
    facet.materialart.
    Unbekannt
    A Complex Mathematical Model of the Human Menstrual Cycle (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: This paper aims at presenting the complex coupled network of the human menstrual cycle to the interested community. Beyond the presently popular smaller models, where important network components arise only as extremely simplified source terms, we add: the GnRH pulse generator in the hypothalamus, receptor binding, and the biosynthesis in the ovaries. Simulation and parameter identification are left to a forthcoming paper.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 4
    facet.materialart.
    Unbekannt
    A continuity result for Nemyckii Operators and some applications in PDE constrained optimal control (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: This work explores two applications of a classical result on the continuity of Nemyckii operators to optimal control with PDEs. First, we present an alternative approach to the analysis of Newton's method for function space problems involving semi-smooth Nemyckii operators. A concise proof for superlinear convergence is presented, and sharpened bounds on the rate of convergence are derived. Second, we derive second order sufficient conditions for problems, where the underlying PDE has poor regularity properties. We point out that the analytical structure in both topics is essentially the same.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 5
    facet.materialart.
    Unbekannt
    Nash Equilibria in Online Sequential Routing Games (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: In this paper, we study the efficiency of Nash equilibria for a sequence of nonatomic routing games. We assume that the games are played consecutively in time in an online fashion: by the time of playing game $i$, future games $i+1,\dots,n$ are not known, and, once players of game $i$ are in equilibrium, their corresponding strategies and costs remain fixed. Given a sequence of games, the cost for the sequence of Nash equilibria is defined as the sum of the cost of each game. We analyze the efficiency of a sequence of Nash equilibria in terms of competitive analysis arising in the online optimization field. Our main result states that the online algorithm $\sl {SeqNash}$ consisting of the sequence of Nash equilibria is $\frac{4n}{2+n}$-competitive for affine linear latency functions. For $n=1$, this result contains the bound on the price of anarchy of $\frac{4}{3}$ for affine linear latency functions of Roughgarden and Tardos [2002] as a special case. Furthermore, we analyze a problem variant with a modified cost function that reflects the total congestion cost, when all games have been played. In this case, we prove an upper bound of $\frac{4n}{2+n}$ on the competitive ratio of $\sl {SeqNash}$. We further prove a lower bound of $\frac{3n-2}{n}$ of $\sl {SeqNash}$ showing that for $n=2$ our upper bound is tight.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 6
    facet.materialart.
    Unbekannt
    Adaptive, Fast and Oblivious Convolution in Evolution Equations with Memory (2006)
    Details
    Publikationsdatum: 2016-06-09
    Beschreibung: To approximate convolutions which occur in evolution equations with memory terms, a variable-stepsize algorithm is presented for which advancing $N$ steps requires only $O(N\log N)$ operations and $O(\log N)$ active memory, in place of $O(N^2)$ operations and $O(N)$ memory for a direct implementation. A basic feature of the fast algorithm is the reduction, via contour integral representations, to differential equations which are solved numerically with adaptive step sizes. Rather than the kernel itself, its Laplace transform is used in the algorithm. The algorithm is illustrated on three examples: a blow-up example originating from a Schrödinger equation with concentrated nonlinearity, chemical reactions with inhibited diffusion, and viscoelasticity with a fractional order constitutive law.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 7
    facet.materialart.
    Unbekannt
    Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics (2006)
    Details
    Publikationsdatum: 2020-11-13
    Beschreibung: This paper deals with MIP-based primal heuristics to be used within a branch-and-cut approach for solving multi-layer telecommunication network design problems. Based on a mixed-integer programming formulation for two network layers, we present three heuristics for solving important subproblems, two of which solve a sub-MIP. On multi-layer planning instances with many parallel logical links, we show the effectiveness of our heuristics in finding good solutions early in the branch-and-cut search tree.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 8
    facet.materialart.
    Unbekannt
    Adaptive Finite Element Simulation of Ventricular Fibrillation Dynamics (2006)
    Details
    Publikationsdatum: 2019-05-10
    Beschreibung: The dynamics of ventricular fibrillation caused by irregular excitation is simulated in the frame of the monodomain model with an action potential model due to Aliev-Panfilov for a human 3D geometry. The numerical solution of this multiscale reaction-diffusion problem is attacked by algorithms which are fully adaptive in both space and time (code library {\sc Kardos}). The obtained results clearly demonstrate an accurate resolution of the cardiac potential during the excitation and the plateau phases (in the regular cycle) as well as after a reentrant excitation (in the irregular cycle).
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 9
    facet.materialart.
    Unbekannt
    Orbitopal Fixing (2006)
    Details
    Publikationsdatum: 2020-12-15
    Beschreibung: The topic of this paper are integer programming models in which a subset of 0/1-variables encode a partitioning of a set of objects into disjoint subsets. Such models can be surprisingly hard to solve by branch-and-cut algorithms if the permutation of the subsets of the partition is irrelevant. This kind of symmetry unnecessarily blows up the branch-and-cut tree. We present a general tool, called orbitopal fixing, for enhancing the capabilities of branch-and-cut algorithms in solving this kind of symmetric integer programming models. We devise a linear time algorithm that, applied at each node of the branch-and-cut tree, removes redundant parts of the tree produced by the above mentioned permutations. The method relies on certain polyhedra, called orbitopes, which have been investigated in (Kaibel and Pfetsch (2006)). However, it does not add inequalities to the model, and thus, it does not increase the difficulty of solving the linear programming relaxations. We demonstrate the computational power of orbitopal fixing at the example of a graph partitioning problem motivated from frequency planning in mobile telecommunication networks.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/pdf
    Format: application/postscript
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 10
    facet.materialart.
    Unbekannt
    Approximability of Unsplittable Shortest Path Routing Problems (2006)
    Details
    Publikationsdatum: 2014-11-10
    Beschreibung: In this paper, we discuss the relation of unsplittable shortest path routing (USPR) to other routing schemes and study the approximability of three USPR network planning problems. Given a digraph $D=(V,A)$ and a set $K$ of directed commodities, an USPR is a set of flow paths $\Phi_{(s,t)}$, $(s,t)\in K$, such that there exists a metric $\lambda=(\lambda_a)\in \mathbb{Z}^A_+$ with respect to which each $\Phi_{(s,t)}$ is the unique shortest $(s,t)$-path. In the \textsc{Min-Con-USPR} problem, we seek for an USPR that minimizes the maximum congestion over all arcs. We show that this problem is hard to approximate within a factor of $\mathcal{O}(|V|^{1-\epsilon})$, but easily approximable within min$(|A|,|K|)$ in general and within $\mathcal{O}(1)$ if the underlying graph is an undirected cycle or a bidirected ring. We also construct examples where the minimum congestion that can be obtained by USPR is a factor of $\Omega(|V|^2)$ larger than that achievable by unsplittable flow routing or by shortest multi-path routing, and a factor of $\Omega(|V|)$ larger than by unsplittable source-invariant routing. In the CAP-USPR problem, we seek for a minimum cost installation of integer arc capacities that admit an USPR of the given commodities. We prove that this problem is $\mathcal{NP}$-hard to approximate within $2-\epsilon$ (even in the undirected case), and we devise approximation algorithms for various special cases. The fixed charge network design problem \textsc{Cap-USPR}, where the task is to find a minimum cost subgraph of $D$ whose fixed arc capacities admit an USPR of the commodities, is shown to be $\mathcal{NPO}$-complete. All three problems are of great practical interest in the planning of telecommunication networks that are based on shortest path routing protocols. Our results indicate that they are harder than the corresponding unsplittable flow or shortest multi-path routing problems.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 11
    facet.materialart.
    Unbekannt
    Availability and Cost Based Evaluation of Demand-wise Shared Protection (2006)
    Details
    Publikationsdatum: 2014-11-11
    Beschreibung: In this paper, we investigate the connection availabilities for the new protection scheme Demand-wise Shared Protection (DSP) and describe an appropriate approach for their computation. The exemplary case study on two realistic network scenarios shows that in most cases the availabilities for DSP are comparable with that for 1+1 path protection and better than in case of shared path protection.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 12
    facet.materialart.
    Unbekannt
    THESEUS - Protein Structure Prediction at ZIB (2006)
    Details
    Publikationsdatum: 2016-06-30
    Beschreibung: THESEUS, the ZIB threading environment, is a parallel implementation of a protein threading based on a multi-queued branch-and-bound optimal search algorithm to find the best sequence-to-structure alignment through a library of template structures. THESEUS uses a template core model based on secondary structure definition and a scoring function based on knowledge-based potentials reflecting pairwise interactions and the chemical environment, as well as pseudo energies for homology detection, loop alignment, and secondary structure matching. The threading core is implemented in C++ as a SPMD parallization architecture using MPI for communication. The environment is designed for generic testing of different scoring functions, e.g. different secondary structure prediction terms, different scoring matrices and information derived from multiple sequence alignments. A validaton of the structure prediction results has been done on the basis of standard threading benchmark sets. THESEUS successfully participated in the 6th Critical Assessment of Techniques for Protein Structure Prediction (CASP) 2004.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 13
    facet.materialart.
    Unbekannt
    On the stability of the multi-queue multi-server processor sharing with limited service (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We consider a multi-queue multi-server system with $n$ servers (processors) and $m$ queues. At the system there arrives a stationary and ergodic stream of $m$ different types of requests with service requirements which are served according to the following $k$-limited head of the line processor sharing discipline: The first $k$ requests at the head of the $m$ queues are served in processor sharing by the $n$ processors, where each request may receive at most the capacity of one processor. By means of sample path analysis and Loynes' monotonicity method, a stationary and ergodic state process is constructed, and a necessary as well as a sufficient condition for the stability of the $m$ separate queues are given, which are tight within the class of all stationary ergodic inputs. These conditions lead to tight necessary and sufficient conditions for the whole system, also in case of permanent customers, generalizing an earlier result by the authors for the case of $n$=$k$=1.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 14
    facet.materialart.
    Unbekannt
    ConfJump : a fast biomolecular sampling method which drills tunnels through high mountains (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: In order to compute the thermodynamic weights of the different metastable conformations of a molecule, we want to approximate the molecule's Boltzmann distribution in a reasonable time. This is an essential issue in computational drug design. The energy landscape of active biomolecules is generally very rough with a lot of high barriers and low regions. Many of the algorithms that perform such samplings (e.g. the hybrid Monte Carlo method) have difficulties with such landscapes. They are trapped in low-energy regions for a very long time and cannot overcome high barriers. Moving from one low-energy region to another is a very rare event. For these reasons, the distribution of the generated sampling points converges very slowly against the thermodynamically correct distribution of the molecule. The idea of ConfJump is to use $a~priori$ knowledge of the localization of low-energy regions to enhance the sampling with artificial jumps between these low-energy regions. The artificial jumps are combined with the hybrid Monte Carlo method. This allows the computation of some dynamical properties of the molecule. In ConfJump, the detailed balance condition is satisfied and the mathematically correct molecular distribution is sampled.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 15
    facet.materialart.
    Unbekannt
    Mathematik für den Volkssport (2006)
    Details
    Publikationsdatum: 2020-02-11
    Beschreibung: "`Volkssport Sudoku"' titelt der Stern in seiner Ausgabe vom 24. Mai2006. In der Tat traut sich derzeit kaum noch eine Zeitung, ohne Sudoku zu erscheinen. Die Begeisterung am Lösen dieser Zahlenrätsel offenbart eine unvermutete Freude am algorithmischen Arbeiten. Mathematisch kann man Sudokus als lineare diophantische Gleichungssysteme mit Nichtnegativitätsbedingungen formulieren. Solche ganzzahligen linearen Programme sind die wichtigsten Modellierungswerkzeuge in zahlreichen Anwendungsgebieten wie z.B. der Optimierung von Telekommunikations- und Verkehrsnetzen. Moderne Verfahren zur Lösung dieser Optimierungsprobleme sind durch Sudokus allerdings deutlich weniger zu beeindrucken als Zeitungsleser.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 16
    facet.materialart.
    Unbekannt
    Mathematical Methods for Physical Layout of Printed Circuit Boards: An Overview (2006)
    Details
    Publikationsdatum: 2020-02-11
    Beschreibung: This article surveys mathematical models and methods used for physical PCB layout, i.e., component placement and wire routing. The main concepts are briefly described together with relevant references.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 17
    facet.materialart.
    Unbekannt
    Competitive Online Multicommodity Routing (2006)
    Details
    Publikationsdatum: 2020-12-15
    Beschreibung: We study online multicommodity minimum cost routing problems in networks, where commodities have to be routed sequentially. Arcs are equipped with load dependent price functions defining the routing weights. We discuss an online algorithm that routes each commodity by minimizing a convex cost function that depends on the demands that are previously routed. We present a competitive analysis of this algorithm showing that for affine linear price functions this algorithm is $4K/2+K$-competitive, where $K$ is the number of commodities. For the parallel arc case this algorithm is optimal. Without restrictions on the price functions and network, no algorithm is competitive. Finally, we investigate a variant in which the demands have to be routed unsplittably.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 18
    facet.materialart.
    Unbekannt
    The extreme points of QSTAB(G) and its implications (2006)
    Details
    Publikationsdatum: 2021-03-16
    Beschreibung: Perfect graphs constitute a well-studied graph class with a rich structure, reflected by many characterizations w.r.t different concepts. Perfect graphs are, e.g., characterized as precisely those graphs $G$ where the stable set polytope STAB$(G)$ coincides with the clique constraint stable set polytope QSTAB$(G)$. For all imperfect graphs STAB$(G) \subset$ QSTAB$(G)$ holds and, therefore, it is natural to measure imperfection in terms of the difference between STAB$(G)$ and QSTAB$(G)$. Several concepts have been developed in this direction, for instance the dilation ratio of STAB$(G)$ and QSTAB$(G)$ which is equivalent to the imperfection ratio imp$(G)$ of $G$. To determine imp$(G)$, both knowledge on the facets of STAB$(G)$ and the extreme points of QSTAB$(G)$ is required. The anti-blocking theory of polyhedra yields all {\em dominating} extreme points of QSTAB$(G)$, provided a complete description of the facets of STAB$(\overline G)$ is known. As this is typically not the case, we extend the result on anti-blocking polyhedra to a {\em complete} characterization of the extreme points of QSTAB$(G)$ by establishing a 1-1 correspondence to the facet-defining subgraphs of $\overline G$. We discuss several consequences, in particular, we give alternative proofs of several famous results.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 19
    facet.materialart.
    Unbekannt
    On exact algorithms for treewidth (2006)
    Details
    Publikationsdatum: 2014-11-10
    Beschreibung: We give experimental and theoretical results on the problem of computing the treewidth of a graph by exact exponential time algorithms using exponential space or using only polynomial space. We first report on an implementation of a dynamic programming algorithm for computing the treewidth of a graph with running time $O^\ast(2^n)$. This algorithm is based on the old dynamic programming method introduced by Held and Karp for the {\sc Tra veling Salesman} problem. We use some optimizations that do not affect the worst case running time but improve on the running time on actual instances and can be seen to be practical for small instances. However, our experiments show that the space use d by the algorithm is an important factor to what input sizes the algorithm is effective. For this purpose, we settle the problem of computing treewidth under the restriction that the space used is only polynomial. In this direction we give a simple $O^\ast(4^n)$ al gorithm that requires {\em polynomial} space. We also show that with a more complicated algorithm, using balanced separators, {\sc Treewidth} can be computed in $O^\ast(2.9512^n)$ time and polynomial space.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 20
    facet.materialart.
    Unbekannt
    Coarse Grained Molecular Kinetics (2006)
    Details
    Publikationsdatum: 2014-03-10
    Beschreibung: The dynamic behavior of molecules can often be described by Markov processes. From computational molecular simulations one can derive transition rates or transition probabilities between subsets of the discretized conformational space. On the basis of this dynamic information, the spatial subsets are combined into a small number of so-called metastable molecular conformations. This is done by clustering methods like the Robust Perron Cluster Analysis (PCCA+). Up to now it is an open question how this coarse graining in space can be transformed to a coarse graining of the Markov chain while preserving the essential dynamic information. In the following article we aim at a consistent coarse graining of transition probabilities or rates on the basis of metastable conformations such that important physical and mathematical relations are preserved. This approach is new because PCCA+ computes molecular conformations as linear combinations of the dominant eigenvectors of the transition matrix which does not hold for other clustering methods.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 21
    facet.materialart.
    Unbekannt
    RSWK/SWD und Faceted Browsing: neue Möglichkeiten einer inhaltlich-intuitiven Navigation (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: Das deutschsprachige Bibliothekswesen verfügt mit den \glqq Regeln für den Schlagwortkatalog \grqq (RSWK) unter Verwendung der \glqq Schlagwortnormdatei \grqq (SWD) über ein Instrumentarium, welches zusammen mit einem \glqq Faceted Browsing \grqq das bisher bestehende Angebot für ein Information Retrieval optimal ergänzen kann. Die Verbindung zwischen Standardvokabular (SWD) und Kettenbildung (RSWK) einerseits und eine nach Facetten-Eigenschaften gegliederte Navigation andererseits unterstützt bestmöglich eine inhaltlich bezogene Recherche. Die Stärken und Schwächen der RSWK/SWD werden erörtert und auch Klassifikationen (DDC und RVK) als mögliche Facetten diskutiert.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 22
    facet.materialart.
    Unbekannt
    Accuracy, Stability, Convergence of Rigorous Thermodynamic Sampling Methods (2006)
    Details
    Publikationsdatum: 2016-06-09
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: masterthesis , doc-type:masterThesis
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 23
    facet.materialart.
    Unbekannt
    Meshless Methods in Confirmation Dynamics (2006)
    Details
    Publikationsdatum: 2016-06-09
    Schlagwort(e): ddc:510
    Sprache: Englisch
    Materialart: doctoralthesis , doc-type:doctoralThesis
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 24
    facet.materialart.
    Unbekannt
    Primal Heuristics for Mixed Integer Programs (2006)
    Details
    Publikationsdatum: 2022-03-14
    Beschreibung: A lot of problems arising in Combinatorial Optimization and Operations Research can be formulated as Mixed Integer Programs (MIP). Although MIP-solving is an NP-hard optimization problem, many practically relevant instances can be solved in reasonable time. In modern MIP-solvers like the branch-cut-and-price-framework SCIP, primal heuristics play a major role in finding and improving feasible solutions at the early steps of the solution process. This helps to reduce the overall computational effort, guides the remaining search process, and proves the feasibility of the MIP model. Furthermore, a heuristic solution with a small gap to optimality often is sufficient in practice. We investigate 16 different heuristics, all of which are available in SCIP. Four of them arise from the literature of the last decade, nine are specific implementations of general heuristic ideas, three have been newly developed. We present an improved version of the feasibility pump heuristic by Fischetti et al., which in experiments produced solutions with only a third of the optimality gap compared to the original version. Furthermore, we introduce two new Large Neighborhood Search (LNS) heuristics. Crossover is an LNS improvement heuristic making use of similarities of diverse MIP solutions to generate new incumbent solutions. RENS is an LNS rounding heuristic which evaluates the space of all possible roundings of a fractional LP-solution. This heuristic makes it possible to determine whether a point can be rounded to an integer solution and which is the best possible rounding. We conclude with a computational comparison of all described heuristics. It points out that a single heuristic on its own has only a slight impact on the overall performance of SCIP, but the combination of all of them reduces the running time by a factor of two compared to a version without any heuristics.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: masterthesis , doc-type:masterThesis
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 25
    facet.materialart.
    Unbekannt
    A cartesian grid finite volume method for the solution of the Poisson equation with variable coefficients and embedded interfaces (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We present a finite volume method for the solution of the two-dimensional Poisson equation $ \nabla\cdot( \beta( {\mbox{\boldmath $x$}}) \nabla u({\mbox{\boldmath $x$}})) = f(\mbox{\boldmath $x$}) $ with variable, discontinuous coefficients and solution discontinuities on irregular domains. The method uses bilinear ansatz functions on Cartesian grids for the solution $u({\mbox{\boldmath $x$})$ resulting in a compact nine-point stencil. The resulting linear problem has been solved with a standard multigrid solver. Singularities associated with vanishing partial volumes of intersected grid cells or the dual bilinear ansatz itself are removed by a two-step asymptotic approach. The method achieves second order of accuracy in the $L^\infty$ and $L^2$ norm.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 26
    facet.materialart.
    Unbekannt
    Efficient Sampling of the Stationary Distribution of Metastable Dynamical Systems (2006)
    Details
    Publikationsdatum: 2014-11-11
    Beschreibung: In this article we aim at an efficient sampling of the stationary distribution of dynamical systems in the presence of metastabilities. In the past decade many sophisticated algorithms have been inven ted in this field. We do not want to simply add a further one. We address the problem that one has applied a sampling algorithm for a dynamical system many times. This leads to different samplings which more or less represent the stationary distribution partially very well, but which are still far away from ergodicity or from the global stationary distribution. We will show how these samplings can be joined together in order to get one global sampling of the stationary distribution.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 27
    facet.materialart.
    Unbekannt
    Polynomial-Time Algorithms for Linear and Convex Optimization on Jump Systems (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: The concept of jump system, introduced by Buchet and Cunningham (1995), is a set of integer points with a certain exchange property. In this paper, we discuss several linear and convex optimization problems on jump systems and show that these problems can be solved in polynomial time under the assumption that a membership oracle for a jump system is available. We firstly present a polynomial-time implementation of the greedy algorithm for the minimization of a linear function. We then consider the minimization of a separable-convex function on a jump system, and propose the first polynomial-time algorithm for this problem. The algorithm is based on the domain reduction approach developed in Shioura (1998). We finally consider the concept of M-convex functions on constant-parity jump systems which has been recently proposed by Murota (2006). It is shown that the minimization of an M-convex function can be solved in polynomial time by the domain reduction approach.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 28
    facet.materialart.
    Unbekannt
    Packing and Partitioning Orbitopes (2006)
    Details
    Publikationsdatum: 2020-12-15
    Beschreibung: We introduce orbitopes as the convex hulls of 0/1-matrices that are lexicographically maximal subject to a group acting on the columns. Special cases are packing and partitioning orbitopes, which arise from restrictions to matrices with at most or exactly one 1-entry in each row, respectively. The goal of investigating these polytopes is to gain insight into ways of breaking certain symmetries in integer programs by adding constraints, e.g., for a well-known formulation of the graph coloring problem. We provide a thorough polyhedral investigation of packing and partitioning orbitopes for the cases in which the group acting on the columns is the cyclic group or the symmetric group. Our main results are complete linear inequality descriptions of these polytopes by facet-defining inequalities. For the cyclic group case, the descriptions turn out to be totally unimodular, while for the symmetric group case, both the description and the proof are more involved. The associated separation problems can be solved in linear time.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 29
    facet.materialart.
    Unbekannt
    LP-Based Local Approximation for Markov Decision Problems (2006)
    Details
    Publikationsdatum: 2014-11-21
    Beschreibung: The standard computational methods for computing the optimal value functions of Markov Decision Problems (MDP) require the exploration of the entire state space. This is practically infeasible for applications with huge numbers of states as they arise, e.\,g., from modeling the decisions in online optimization problems by MDPs. Exploiting column generation techniques, we propose and apply an LP-based method to determine an $\varepsilon$-approximation of the optimal value function at a given state by inspecting only states in a small neighborhood. In the context of online optimization problems, we use these methods in order to evaluate the quality of concrete policies with respect to given initial states. Moreover, the tools can also be used to obtain evidence of the impact of single decisions. This way, they can be utilized in the design of policies.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 30
    facet.materialart.
    Unbekannt
    Ein gemischt-ganzzahliges lineares Optimierungsmodell für ein Laserschweißproblem im Karosseriebau (2006)
    Details
    Publikationsdatum: 2014-11-21
    Beschreibung: Wir beschäftigen uns mit dem Problem der Betriebsplanung von Laserschweißrobotern im Karosseriebau. Gegeben ist eine Menge von Schweißnähten, die innerhalb einer Fertigungszelle an einem Karosserieteil gefertigt werden müssen. Die Schweißnähte werden durch mehrere parallel betriebene Roboter bearbeitet. Die Aufgabe besteht darin, für jeden Roboter eine Reihenfolge und eine zeitliche Koordinierung seiner Bewegungen zu finden, so dass alle Schweißnähte innerhalb der Taktzeit der Fertigungszelle bearbeitet werden und so wenig Laserquellen wie möglich eingesetzt werden. Dabei müssen einige Nebenbedingungen berücksichtigt werden. Für dieses spezielle Schweißproblem haben wir eine Formulierung als gemischt-ganzzahliges lineares Programm entwickelt, welches sich für die untersuchten praktischen Fälle sehr schnell lösen lässt.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 31
    facet.materialart.
    Unbekannt
    Software for Teaching Modeling of Integer Programming Problems (2006)
    Details
    Publikationsdatum: 2021-08-05
    Beschreibung: Modern applications of mathematical programming must take into account a multitude of technical details, business demands, and legal requirements. Teaching the mathematical modeling of such issues and their interrelations requires real-world examples that are well beyond the toy sizes that can be tackled with the student editions of most commercial software packages. We present a new tool, which is freely available for academic use including complete source code. It consists of an algebraic modeling language and a linear mixed integer programming solver. The performance and features of the tool are in the range of current state-of-the-art commercial tools, though not in all aspects as good as the best ones. Our tool does allow the execution and analysis of large real-world instances in the classroom and can therefore enhance the teaching of problem solving issues. Teaching experience has been gathered and practical usability was tested in classes at several universities and a two week intensive block course at TU Berlin. The feedback from students and teachers has been very positive.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 32
    facet.materialart.
    Unbekannt
    On the Bottleneck Shortest Path Problem (2006)
    Details
    Publikationsdatum: 2014-11-21
    Beschreibung: The Bottleneck Shortest Path Problem is a basic problem in network optimization. The goal is to determine the limiting capacity of any path between two specified vertices of the network. This is equivalent to determining the unsplittable maximum flow between the two vertices. In this note we analyze the complexity of the problem, its relation to the Shortest Path Problem, and the impact of the underlying machine/computation model.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 33
    facet.materialart.
    Unbekannt
    Graph Coloring Manifolds (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We introduce a new and rich class of graph coloring manifolds via the Hom complex construction of Lov\´{a}sz. The class comprises examples of Stiefel manifolds, series of spheres and products of spheres, cubical surfaces, as well as examples of Seifert manifolds. Asymptotically, graph coloring manifolds provide examples of highly connected, highly symmetric manifolds.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 34
    facet.materialart.
    Unbekannt
    Polyhedra of Genus 3 with 10 Vertices and Minimal Coordinates (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We give coordinate-minimal geometric realizations in general position for 17 of the 20 vertex-minimal triangulations of the orientable surface of genus 3 in the 5x5x5-cube.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 35
    facet.materialart.
    Unbekannt
    ConFlow? A new space-based Application for complete Conformational Analysis of Molecules (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: Biochemical interactions are determined by the 3D-structure of the involved components - thus the identification of conformations is a key for many applications in rational drug design. {\sf ConFlow} is a new multilevel approach to conformational analysis with main focus on completeness in investigation of conformational space. In contrast to known conformational analysis, the starting point for design is a space-based description of conformational areas. A tight integration of sampling and analysis leads to an identification of conformational areas simultaneously during sampling. An incremental decomposition of high-dimensional conformational space is used to guide the analysis. A new concept for the description of conformations and their path connected components based on convex hulls and {\em Hypercubes}is developed. The first results of the {\sf ConFlow} application constitute a 'proof of concept' and are further more highly encouraging. In comparison to conventional industrial applications, {\sf ConFlow} achieves higher accuracy and a specified degree of completeness with comparable effort.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 36
    facet.materialart.
    Unbekannt
    Iteratively Solving Linear Inverse Problems under General Convex Contraints (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We consider linear inverse problems where the solution is assumed to fulfill some general homogeneous convex constraint. We develop an algorithm that amounts to a projected Landweber iteration and that provides and iterative approach to the solution of this inverse problem. For relatively moderate assumptions on the constraint we can always prove weak convergence of the iterative scheme. In certain cases, i.e. for special families of convex constraints, weak convergence implies norm convergence. The presented approach covers a wide range of problems, e.g. Besov- or BV-restoration for which we present also numerical experiments in the context of image processing.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 37
    facet.materialart.
    Unbekannt
    Stable computation of probability densities for metastable dynamical systems (2006)
    Details
    Publikationsdatum: 2014-03-10
    Beschreibung: Whenever the invariant stationary density of metastable dynamical systems decomposes into almost invariant partial densities, its computation as eigenvector of some transition probability matrix is an ill-conditioned problem. In order to avoid this computational difficulty, we suggest to apply an aggregation/disaggregation method which only addresses wellconditioned sub-problems and thus results in a stable algorithm. In contrast to existing methods, the aggregation step is done via a sampling algorithm which covers only small patches of the sampling space. Finally, the theoretical analysis is illustrated by two biomolecular examples.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 38
    facet.materialart.
    Unbekannt
    Facets of the (s,t)-p-path polytope (2006)
    Details
    Publikationsdatum: 2016-02-29
    Beschreibung: \noindent We give a partial description of the $(s,t)-p$-path polytope of a directed graph $D$ which is the convex hull of the incidence vectors of simple directed $(s,t)$-paths in $D$ of length $p$. First, we point out how the $(s,t)-p$-path polytope is located in the family of path and cycle polyhedra. Next, we give some classes of valid inequalities which are very similar to inequalities which are valid for the $p$-cycle polytope, that is, the convex hull of the incidence vectors of simple cycles of length $p$ in $D$. We give necessary and sufficient conditions for these inequalities to be facet defining. Furthermore, we consider a class of inequalities that has been identifie d to be valid for $(s,t)$-paths of cardinality at most $p$. Finally, we transfer the results to related polytopes, in particular, the undirected counterpart of the $(s,t)-p$-path polytope.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 39
    facet.materialart.
    Unbekannt
    A Contact-Stabilized Newmark Method for Dynamical Contact Problems (2006)
    Details
    Publikationsdatum: 2020-11-13
    Beschreibung: The numerical integration of dynamical contact problems often leads to instabilities at contact boundaries caused by the non-penetration condition between bodies in contact. Even a recent energy dissipative modification due to Kane et al. (1999), which discretizes the non-penetration constraints implicitly, is not able to circumvent artificial oscillations. For this reason, the present paper suggests a contact stabilization which avoids artificial oscillations at contact interfaces and is also energy dissipative. The key idea of this contact stabilization is an additional $L^2$-projection at contact interfaces, which can easily be added to any existing time integration scheme. In case of a lumped mass matrix, this projection can be carried out completely locally, thus creating only negligible additional numerical cost. For the new scheme, an elementary analysis is given, which is confirmed by numerical findings in an illustrative test example (Hertzian two body contact).
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 40
    facet.materialart.
    Unbekannt
    Implementation eines Resourcebrokers im Kontext eines Grid-Datenmanagement-Systems (2006)
    Details
    Publikationsdatum: 2016-06-30
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: masterthesis , doc-type:masterThesis
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 41
    facet.materialart.
    Unbekannt
    Enumeration and Random Realization of Triangulated Surfaces (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We discuss different approaches for the enumeration of triangulated surfaces. In particular, we enumerate all triangulated surfaces with 9 and 10 vertices. We also show how geometric realizations of orientable surfaces with few vertices can be obtained by choosing coordinates randomly.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 42
    facet.materialart.
    Unbekannt
    Note on L#-convex Function Minimization Algorithms: Comparison of Murota's and Kolmogorov's Algorithms (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: The concept of L##-convexity is introduced by Fujishige--Murota (2000) as a discrete convexity for functions defined over the integer lattice. The main aim of this note is to understand the difference of the two algorithms for L##-convex function minimization: Murota's steepest descent algorithm (2003) and Kolmogorov's primal algorithm (2005).
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 43
    facet.materialart.
    Unbekannt
    Triangulated Manifolds with Few Vertices: Combinatorial Manifolds (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: In this survey on combinatorial properties of triangulated manifolds we discuss various lower bounds on the number of vertices of simplicial and combinatorial manifolds. Moreover, we give a list of all known examples of vertex-minimal triangulations.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 44
    facet.materialart.
    Unbekannt
    Optimizing the Landside Operation of a Container Terminal (2006)
    Details
    Publikationsdatum: 2020-02-11
    Beschreibung: This paper concerns the problem of operating a landside container exchange area that is serviced by multiple semi-automated rail mounted gantry cranes (RMGs) that are moving on a single bi-directional traveling lane. Such a facility is being built by Patrick Corporation at the Port Botany terminal in Sydney. The gantry cranes are a scarce resource and handle the bulk of container movements. Thus, they require a sophisticated analysis to achieve near optimal utilization. We present a three stage algorithm to manage the container exchange facility, including the scheduling of cranes, the control of associated short-term container stacking, and the allocation of delivery locations for trucks and other container transporters. The key components of our approach are a time scale decomposition, whereby an integer program controls decisions across a long time horizon to produce a balanced plan that is fed to a series of short time scale online subproblems, and a highly efficient space-time divisioning of short term storage areas. A computational evaluation shows that our heuristic can find effective solutions for the planning problem; on real-world data it yields a solution at most~8\% above a lower bound on optimal RMG utilization.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 45
    facet.materialart.
    Unbekannt
    Triangulated Manifolds with Few Vertices: Vertex-Transitive Triangulations I (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We describe an algorithm for the enumeration of (candidates of) vertex-transitive combinatorial $d$-manifolds. With an implementation of our algorithm, we determine, up to combinatorial equivalence, all combinatorial manifolds with a vertex-transitive automorphism group on $n\leq 13$ vertices. With the exception of actions of groups of small order, the enumeration is extended to 14 and 15 vertices.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 46
    facet.materialart.
    Unbekannt
    Polyhedra of Genus 2 with 10 Vertices and Minimal Coordinates (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We give coordinate-minimal geometric realizations in general position of all 865 vertex-minimal triangulations of the orientable surface of genus 2 in the 4x4x4-cube.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 47
    facet.materialart.
    Unbekannt
    Combinatorial 3-Manifolds with 10 Vertices (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We give a complete enumeration of combinatorial 3-manifolds with 10 vertices: There are precisely 247882 triangulated 3-spheres with 10 vertices as well as 518 vertex-minimal triangulations of the sphere product $S^2 x S^1$ and 615 triangulations of the twisted sphere product $S^2 \underline{x} S^1$. An analysis of the 3-spheres with up to 10 vertices shows that all these spheres are shellable, but that there are 29 vertex-minimal non-shellable 3-balls with 9 vertices.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 48
    facet.materialart.
    Unbekannt
    Adaptive Linearly Implicit Methods for Linear Poroelastic Equations (2006)
    Details
    Publikationsdatum: 2019-05-10
    Beschreibung: Adaptive numerical methods in time and space are introduced and studied for linear poroelastic models in two and three space dimensions. We present equivalent models for linear poroelasticity and choose both the {\em displacement--pressure} and the {\em stress--pressure} formulation for our computations. Their discretizations are provided by means of linearly implicit schemes in time and linear finite elements in space. Our concept of adaptivity opens a way to a fast and reliable simulation of different loading cases defined by corresponding boundary conditions. We present some examples using our code {\sf Kardos} and show that the method works efficiently. In particular, it could be used in the simulation of some bone healing models.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 49
    facet.materialart.
    Unbekannt
    A computational approach to microRNA detection (2006)
    Details
    Publikationsdatum: 2016-06-30
    Beschreibung: During the last few years more and more functionalities of RNA have been discovered that were previously thought of being carried out by proteins alone. One of the most striking discoveries was the de tection of microRNAs, a class of noncoding RNAs that play an important role in post-transcriptional gene regulation. Large-scale analyses are needed for the still increasingly growing amount of sequen ce data derived from new experimental technologies. In this paper we present a framework for the detection of the distinctive precursor structure of microRNAS that is based on the well-known Smith-Wat erman algorithm and various filtering steps. We conducted experiments on real genomic data and we found several new putative hits for microRNA precursor structures.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 50
    facet.materialart.
    Unbekannt
    Neustart für Bibliotheken ins Informationszeitalter (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: Wir erleben zu Beginn des aufkommenden Informationszeitalters mit dem Siegeszug von Google und anderen Internet-Technologien einen Wandel im Verhalten von Wissenschaftlern und Studenten, der mit dem Einsatz von {\sl Google Scholar} und {\sl Google Book Search} einen Paradigmenwechsel für Bibliotheken und Informationsversorger gleichkommt. Der Artikel untersucht die technischen Hintergründe für den Erfolg dieser besonderen Art des Information Retrievals: Fulltext Indexing und Citation Ranking als besondere Form des Information Minig. Er diskutiert Stärken und auch Schwächen des Google-Ansatzes. Der Autor stellt sich auch der Frage, unter welchen Bedingungen es möglich ist, ein zu {\sl Google Scholar} und der {\sl Google Book Search} konkurrenzfähiges Retrieval in der Landschaft der Bibliotheken und Bibliotheksverbünde zu entrichten. Die These ist, dass dieses unter Einsatz des {\sl Open Source} Indexierers {\sl Lucene} und des Web-Robots {\sl Nutch} möglich ist. Bibliotheken können durch gezielten Einsatz solcher Internet-Technologien dem Nutzer die Leistungen, welche Google uns mit seinen Tools im {\sl Visible Web} und mit Referenzen auf {\sl Citations} in der Welt der Literatur zur Verfügung stellt, in vergleichbarer Art auch für ihre eigenen durch Lizenzen geschützten digitalen Journale und ihre speziellen lokal verfügbaren Ressourcen, auf die Internet-Suchmaschinen keine Zugriff haben, anbieten. Es besteht die Hoffnung, dass Nutzer dann nicht - wie in einer kürzlichen Studie des OCLC konstatiert - überwiegend im Internet verbleiben, sondern bei ihrer Suche auch den Weg zu den Angeboten der örtlichen Bibliothek attraktiv finden.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 51
    facet.materialart.
    Unbekannt
    Waiting times for M/M systems under generalized processor sharing (2006)
    Details
    Publikationsdatum: 2014-02-26
    Beschreibung: We consider a system where the arrivals form a Poisson process and the required service times of the requests are exponentially distributed. According to the generalized processor sharing discipline, each request in the system receives a fraction of the capacity of one processor which depends on the actual number of requests in the system. We derive systems of ordinary differential equations for the LST and for the moments of the conditional waiting time of a request with given required service time as well as a stable and fast recursive algorithm for the LST of the second moment of the conditional waiting time, which in particular yields the second moment of the unconditional waiting time. Moreover, asymptotically tight upper bounds for the moments of the conditional waiting time are given. The presented numerical results for the first two moments of the sojourn times in the $M/M/m-PS$ system show that the proposed algorithms work well.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 52
    facet.materialart.
    Unbekannt
    Kombinatorische Optimierung –Inhalte und Methoden für einen authentischen Mathematikunterricht (2006)
    Details
    Publikationsdatum: 2020-08-05
    Beschreibung: wird nachgereicht
    Schlagwort(e): ddc:510
    Sprache: Englisch
    Materialart: doctoralthesis , doc-type:doctoralThesis
    Format: application/pdf
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 53
    facet.materialart.
    Unbekannt
    Domain Decomposition Method for Maxwell's Equations: Scattering off Periodic Structures (2006)
    Details
    Publikationsdatum: 2022-07-07
    Beschreibung: We present a domain decomposition approach for the computation of the electromagnetic field within periodic structures. We use a Schwarz method with transparent boundary conditions at the interfaces of the domains. Transparent boundary conditions are approximated by the perfectly matched layer method (PML). To cope with Wood anomalies appearing in periodic structures an adaptive strategy to determine optimal PML parameters is developed. We focus on the application to typical EUV lithography line masks. Light propagation within the multi-layer stack of the EUV mask is treated analytically. This results in a drastic reduction of the computational costs and allows for the simulation of next generation lithography masks on a standard personal computer.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/pdf
    Format: application/postscript
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    OPUS
  • 54
    Digitale Medien
    Digitale Medien
    Stability of steady states in nucleic acid poly[d(A-T)] synthesis and the stirred flow reactor (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1-14 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The template directed synthesis of poly[d(A-T)] from the nucleoside triphosphates in the presence of DNA polymerase I is carried out continuously in a stirred flow reactor for the first time. The initial objective is to test the kinetic stability of the established steady states at various flow rates. Graphical analysis predicts instable steady states for certain high flow rates. As a consequence of instabilities multiple steady states and steady-state hysteresis may occur. Steady-state hysteresis has now been found experimentally. For a different enzyme fraction of low exonuclease activity we found the steady-state absorbance at 260 nm to be almost invariant with flow rate at high enzyme concentrations even if the flow rate was increased by a large factor. We call this phenomenon kinetic buffering. Relaxation of a large flow perturbation approaches the steady state in a sigmoidal fashion. Concentration oscillations at 260 nm occurred in one experiment using an enzyme fraction of low exonuclease activity after perturbing the steady state by monomer (dATP). Advantages of the stirred flow reactor method over serial transfer are discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150102
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 55
    Digitale Medien
    Digitale Medien
    Circular dichroism of corticotropin, fragment 1-24, and model compounds. An assessment of the contributions of the peptide chromophore and aromatic residues (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 43-59 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The far-ultraviolet circular dichroic spectrum of the 39-residue peptide hormone porcine corticotropin and the biologically active fragment corticotropin 1-24 is negative from 250 nm to 195 nm in water, but in 6M guanidinium chloride a positive band appears at about 225 nm. The temperature and guanidinium chloride dependence of this spectral transition indicates the absence of any stable ordered secondary structure in corticotropin and the spectrum is seen to be in only partial agreement with results using the model peptide chromophore, Ala-Ala-Ala. Using oligopeptides containing aromatic amino acid residues sandwiched between glycyl residues, it is shown that the shape and intensity of the corticotropin 225 nm positive band which appears in 6M guanidinium chloride is in agreement with the far-ultraviolet transitions of the aromatic chromophores in the hormone. Curve resolution of the near-ultraviolet circular dichroic spectrum of corticotropin and comparison of the rotational strengths of the phenylalanyl and tyrosyl bands reveals no evidence for increased rotational freedom in 6M guanidinium hydrochloride. Spectral changes are observed, however, in the transitions arising from the single tryptophan. This study suggests that corticotropin in aqueous solution may serve as a better model for the circular dichroic spectrum of the aperiodic regions in globular proteins than either synthetic homopolypeptides or reference proteins for which spectral and X-ray diffraction data are available.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150106
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 56
    Digitale Medien
    Digitale Medien
    Polynucleotide circular dichroism calculations: Use of an all-order classical coupled oscillator polarizability theory (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 131-152 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An all-order classical coupled oscillator theory in which monomer band shapes are explicity taken into account is applied to the calculations of polynucleotide circular dichroism. Calculations are shown for ApA and oligoadenylic acid of varying chain lengths, in both RNA and B-DNA geometry, and the advantages of this theory are assessed. By introducing an effective dielectric constant, good agreement with measured spectra is obtained. Variations in monomer parameters are tested in an attempt to eliminate remaining discrepancies between calculated and measured spectra.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150110
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 57
    Digitale Medien
    Digitale Medien
    Raman studies of bovine serum albumin (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 203-218 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Raman Spectra of bovine serum albumin have been obtained in the solute state, in alkaline and acidic solutions, and in the gel. The reversible denaturations of bovine serum albumin solutions by heat, acid's, and alkali were studied and a new mechanism for heat denaturation has been proposed based on a continuous unfolding of the α-helices.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150114
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 58
    Digitale Medien
    Digitale Medien
    Low-frequency Raman spectra of lysozyme (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 219-225 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New techniques in laser Raman spectroscopy are used to obtain spectra of aqueous solutions of lysozylme for frequency shifts as small as 5 cm-1. In addition, Raman measurements are made on two crystalline forms of hen egg white lysozyme. The spectra obtained from the solution and from the crystal are found to be similar for frequencies above 100 cm-1. However, a low-frequency band at 25 cm-1 observed in crystalline lysozyme is not found in the solution, indicating that this band cannot be attributed to an internal molecular vibration.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150115
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 59
    Digitale Medien
    Digitale Medien
    Thickness and density of protein films by optical mixing spectroscopy (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 257-263 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The adsorption of protein films on polystyrene latex spheres was studied by optical mixing spectroscopy. With this technique, we show that both the hydrodynamic thickness of protein films and their optical density can be measured. Thus, we found that films of the glycoproteins isolated from the human erythrocyte membrane were four times as thick as films of either human serum albumin or bovine serum albumin for about the same surface coverage. This result suggests an end-on orientation for the adsorbed glycoprotein molecules, which is consistent with the model proposed by others for the orientation of these molecules at the surface of the red blood cell itself.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150204
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 60
    Digitale Medien
    Digitale Medien
    Preferential solvent binding and change in conformation of bovine serum albumin in 2-chloroethanol-water mixed solvents (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 293-299 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Solvent binding to bovine serum albumin in 2-chloroethanol-water mixed solvents of different composition, measured previously by Inoue and Timasheff (Biopolymers (1972) 11, 737-43) is applied to a hydrodynamic study of the solvated protein.From sedimentation and diffusion data, the apparent molecular weight of the solvated protein particle can be calculated, provided an average partial specific volume, computed from the composition of the particle, is introduced in Svedberg's equation. The unsolvated molecular weight of the protein can than be calculated by subtraction of the bound solvent. Further data on the hydrodynamic particle (f/fmin and axial ratio of the equivalent ellipsoid) are readily calculated from these experiments, and reinforce the supposition that 2-chloroethanol is a strong helix-inducing solvent.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150207
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 61
    Digitale Medien
    Digitale Medien
    Masthead (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150101
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 62
    Digitale Medien
    Digitale Medien
    Cooperative ligand binding by ferrihemoglobin: An experimental artifact? (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 403-414 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: We have carried out a detailed study of ligand binding of ferrihemoglobins under various conditions. Our results show that n varies with time and that this variation is paralleled by changes in the spectrum of methemoglobin. This suggests some form of structural perturbation. The time-dependent value of n is discussed in terms of the observed spectral changes accompanying prolonged equilibration.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150216
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 63
    Digitale Medien
    Digitale Medien
    1H Nuclear magnetic resonance studies of histidine-containing di- and tripeptides. Estimation of the effects of charged groups on the pKa value of the imidazole ring (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 393-401 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The nmr titration curves of chemical shifts versus pH were observed for the protons of various histidine-containing di- and tripeptides. With these results, the macroscopic pKa values and the chemical shifts intrinsic to each ionic species were determined by a computer curve-fitting based on a simple acid dissociation sequence. The pKa value of the imidazole ring in N-acetyl-L-histidine methylamide was assumed to represent the intrinsic (or unperturbed) pKa of the imidazole rings of histidine having peptide linkages at both the CO and NH sides. The pKa values of the imidazole rings observed for most di- and tripeptides were reasonably reproduced by simple calculations using the intrinsic value and the perturbations due to the CO2- and NH3+ groups located at various positions. Some other factors affecting the pKa value of the imidazole ring are also discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150215
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 64
    Digitale Medien
    Digitale Medien
    Masthead (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150201
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 65
    Digitale Medien
    Digitale Medien
    Interpretation of hypochromic and hyperchromic intensity changes in the Raman spectra of polypeptides and polynucleotides undergoing transition (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 241-255 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The hyperchromic and hypochromic changes in the intensity of the amide-I and amide-III lines of polypeptides and certain ring vibrations of the bases of polynucleotides are shown to be related to similar changes in the lower energy uv absorption bands. The selection rules strictly limit the pairs of excited electronic states that can contribute to the elements of the polarizability matrix. An energy-dependent term in this equation weights the contribution of the pairs of electronic transitions in favor of those involving the lower energy transitions. For both polypeptides and polynucleotides, there is a large hypochromic inensity change in the first π → π* exciton band upon the coil-to-helix transition. Through the selection rules, certain conformationally sensitive Raman lines are shown to derive their intensity predominantly from this band and hence also display hypochromism. Again, through an application of the selection rules, certain Raman lines can be demonstrated to depend predominantly for their intensity upon the n → π* transition, and consequently have the opposite hyperchromic intensity change upon the same conformational transition.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150203
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 66
    Digitale Medien
    Digitale Medien
    Length and dipole moment of TMV by laser signal-averaging transient electric birefringence (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 301-315 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Transient electric birefringence experiments have been performed on well-characterized highly monodisperse samples of tobacco mosaic virus (TMV). Experiments and calculations are presented that show that the sensitivity and accuracy of the traditional transient electric birefringence technique can be enhanced by several orders of magnitude through the use of a low-powered laser and crystal polarizing optics, signal averaging, and digital data processing. Measurements of the field-free decay of the birefringence yield for the rotational diffusion coefficient, DR = 318 ± 3 sec-1. The length of the rodlike virion, calculated from the Broersma equation with this value of DR and a rod diameter of 15 nm, is 292.5 ± 1.0 nm. Measurements of the growth of the birefringence when an electric field is applied across the sample yield μ2/kT(α∥ - α⊥) = 0.47 ± 0.07, where μ is the permanent dipole moment (assumed parallel to the symmetry axis of the virus) and α∥ - α⊥ is the electrical polarizability anistropy of the virus. Using the value of α∥ - α⊥ measured by O'Konski et al., we then obtain μ = 2.5 × 10-14 esu cm.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150208
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 67
    Digitale Medien
    Digitale Medien
    High-resolution nmr study of yeast tRNACUALeu and the native and denatured conformers of yeast tRNAUUGLeuSubmitted by BFR in partial fulfillment of the requirements for the Ph.D. degree in chemistry at the University of California, Riverside. (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 325-336 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The high-resolution nmr spectrum of baker's yeast tRNACUALeu, a recently sequenced non-denaturable tRNA, has been compared with the spectra of the native and denatured conformers of the closely related species tRNAUUGLeu. Because of the presence of many common base pairs in the different tRNA's, it is possible to assign most of the low-field resonances to specific secondary-structure base pairs. A comparison of the observed positions of the various resonances with those predicted by a semiempirical ring-current shift theory shows a root-mean-square deviation of 0.14, 0.11, and 0.12 ppm for tRNAUUGLeu (native), and tRNAUUGLeu (denatured), respectively. These results support the ring-current shift theory currently used to interpret the low-field nmr spectra of the tRNA molecules. Differences between the predicted and observed positions of some resonances provide new evidence for higher order effects such as shifts from second nearest neighbors, anomalous shifts exerted by G·U base pairs, and tertiary-structure effects. A model that was previously proposed for the denatured conformer of tRNAUUGLeu is also supported.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150210
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 68
    Digitale Medien
    Digitale Medien
    Masthead (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150301
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 69
    Digitale Medien
    Digitale Medien
    On the application of polyelectrolyte limiting laws to the helix-coil transition of DNA. IV. Dependence of helix stability on the concentration of divalent metal ions (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 457-468 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The molecular theory of the previous paper in this series is extended to determine the effect of divalent metal ions on helix stability relative to coil at fixed ionic strength and nucleotide phosphate concentration. Specification of the state of condensed counterions, as well as their concentration, is essential for the solution of this problem, and it is assumed that they translate freely within a thin cylindrical shell close to the polynucleotide. As a function of divalent counterion concentration mB2+ the relative stability of the helix is highly nonlinear. Although the overall trend is that the helix stability increases with addition of divalent metal ion, there is a narrow concentration range for which it decreases slightly. The behavior of the relative stability as a function of mB2+ is determined by the translational degrees of freedom of the counterions, both univalent and divalent, both condensed and uncondensed. Detailed comparison of the theory with data is not given here, but it is pointed out that the calculated values of the relative stability are consistent with the order of magnitude of the observed effect Mg2+ on the melting temperature.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150303
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 70
    Digitale Medien
    Digitale Medien
    An X-ray study of poly(L-prolyl-L-α-phenylglycyl-L-proline) (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 503-506 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: X-ray diffraction studies have been made on the polytripeptide poly(L-prolyl-L-α-phenylglycyl-L-proline). Its structure has been found to be helical, with a poly(L-proline) II conformation, packed in an orthorhombic lattice, space group P21212, with a = 14.3 Å, b = 13.5 Å, and c = 9.4 Å.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150306
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 71
    Digitale Medien
    Digitale Medien
    Effect of saturation of the ion atmosphere polarization on the orientation factor of the electric birefringence of rodlike polyelectrolytes (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 583-587 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150313
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 72
    Digitale Medien
    Digitale Medien
    Measurement of circular dichroism using a thin cell (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 591-594 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150315
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 73
    Digitale Medien
    Digitale Medien
    Masthead (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150401
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 74
    Digitale Medien
    Digitale Medien
    Molecular forces in ribosomes and polynucleotide complexes (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 649-653 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The stability constant of the complex of tRNA with 50S subunits of ribosomes was compared in ordinary and heavy water. A considerable effect (about fourfold) was observed, showing the importance of hydrogen bonds in this interaction. In addition, the isotope effect of complementary polynucleotide interaction was measured for two examples. In the case of the binary complex of heptainosinic acid oligomers with poly(C) in the presence of 10-3 M MgCl2, the transfer from ordinary to heavy water gave an increase of the stability constant of about 5%. But in the case of a ternary complex of hexaadenylic acid with poly(U) under the same conditions, the stability constant in D2O increased threefold. The isotope effect depends strongly on magnesium ion concentration and is possibly due to some specific mechanism of magnesium ion complexing involving water molecules.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150405
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 75
    Digitale Medien
    Digitale Medien
    The effect of binding on the melting temperature of biopolymers (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 999-1000 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150513
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 76
    Digitale Medien
    Digitale Medien
    Calculations of the conformation of mono-, di-, and regular polynucleotides (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1009-1013 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150516
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 77
    Digitale Medien
    Digitale Medien
    Calculation of the molecular parameters of the α-helix-coil and β-structure-coil transitions (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1061-1080 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Monte-Carlo calculations of geometric and thermodynamic characteristics of the α-helix and the β-structure of polypeptides have been carried out. To describe a hydrogen bond both the Lippincott-Schroeder and Morse potentials were used. The internal rotation angles ϕ and ψ in the α-helix have been shown to fluctuate in the range of ±7°. The distribution functions on angles ϕ and ψ and on hydrogen bond lengths and angles in the α-helix have been computed and compared with those in myoglobin and lysozyme. Thermodynamic characteristics of the α-helix calculated in different approximations with the two forms of the hydrogen bond potentials have also been compared. The data obtained are close to the experimental values for polypeptides in neutral solution.Some geometric and thermodynamic characteristics of the regular parallel and antiparallel and irregular antiparallel β-structure have been found. In the β-structure the internal rotation angles vary within the interval ±15-20°. An increase in the cross and longitudinal dimensions of the β-structure only slightly influence both the geometric and thermodynamic characteristics.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150604
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 78
    Digitale Medien
    Digitale Medien
    Co-oligopeptides of aromatic amino acids and glycine with a variable distance between the aromatic residues. III. Co-oligopeptides of L-phenylalanine, L-tryptophan, and glycine: Synthesis and ultraviolet absorption properties (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1103-1117 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The preparation of the co-oligopeptides of the series H-Gly-Phe-(Gly)n-Trp-Gly-OH (n = 0, 1, 2) and of other free peptides of glycine, L-tryptophan, and L-phenylalanine is reported. The syntheses have been carried out by conventional methods, using N-hydroxysuccinimide esters for the coupling steps. The ultraviolet absorption properties of the free peptides have been investigated in water. No hypo- or hyperchromicity was found for the aromatic chromophores, with the exception of H-Gly-Phe-Trp-OH, which shows a small but significant hypochromicity. The contribution of the peptide bond to the molar absorptivity in the far ultraviolet has been separated from that of the side chain plus the —COO- group by plotting the measured molar absorptivity ∊ of the farthest accessible uv maximum as a function of the number of peptide bonds (nA). The peptide bond contribution proved to be independent of nA in the range nA = 1-5, thus ruling out the onset of helical conformations in the longer chain peptides.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150607
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 79
    Digitale Medien
    Digitale Medien
    Spatial electron distribution and population analysis of amides, carboxylic acid, and peptides, and their relation to empirical potential functions (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1167-1200 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The properties of the electron distribution in amides, peptides, and carboxylic acids, obtained from ab-initio molecular orbital calculations using both minimal and extended basis sets have been studied. These properties are discussed in terms of some of the common assumptions made in empirical conformational calculations of biomolecules. In particular, population analyses of 15 compounds in these families were carried out with both the minimal and extended basis sets, and compared with results of CNDO/2 calculations. It is suggested that population analysis is a useful tool for recognizing patterns of charge distributions, and investigating the transferability of parameters of different functional groups. However, its use for providing partial charges for conformational analysis is a questionable procedure.A more detailed analysis of the charge distribution was carried out by calculating the spatial electron distribution in the four compounds, N-methylacetamide, acetic acid, diketopiperazine, and N-acetyl-N′-methylalanine. Both total electron-density maps and differencedensity maps are presented. The properties of the overall shape of the molecule and the atoms in the molecule, are discussed in terms of the former along with three-dimensional shape plots of the total density. The distortion accompanying molecular formation, resulting in such features as the lone pair orbital and “bonding deensities” is discussed in terms of the difference maps. Semiquantitative estimates of the bonding and orbital densities resulting from the integration of the densities are also presented. Finally, one of the novel features of the study is the presentation of three-dimensional surfaces of constant difference densities from which the shapes of the orbitals and bonding densities emerge.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150612
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 80
    Digitale Medien
    Digitale Medien
    Conformational properties of the sequential polyproline analogs poly(Pro-Aze-Pro) and poly(Aze-Pro-Aze) (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1233-1242 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The lack of the positive band at around 226 nm in the CD spectra of poly(prolyl-azetidine-2-carbonyl-proline) in trifluoroethanol and of poly(azetidine-2-carbonyl-prolyl-azetidine-2-carboxylic) acid in F3EtOH and water, the hyperchromism of the absorption maximum at about 202 nm, and the extremely small intensity of the Cβ-Pro, Cγ-Pro, and Cβ-Aze signals for the cis peptide bonds in the 13C nmr spectrum of poly(Pro-Aze-Pro) in F3EtOH indicate that both polyproline analogs exist as disordered chains in this solvent, the trans peptide group being maintained. The disordering of the chains is attributed to an increase in the accessible range of ψ due to the reduced dimensions of the square ring of L-azetidine-2-carboxylic acid residue relative to the pyrrolidine ring of proline and to strong interactions of the haloalcohol with the peptide groups of the chains.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150702
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 81
    Digitale Medien
    Digitale Medien
    Rapid characterization of protein molecular weights and hydrodynamic structures by quasielastic laser-light scattering (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1283-1299 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two methods for the characterization of protein molecular weights from their diffusion coefficients are discussed. These measurements can be made quickly and reliably at low concentrations using quasielastic light-scattering techniques. First, an empirical calibration of the diffusion coefficient at infinite dilution of denatured random coils against molecular weight is reported. The second method combines the measurement of D0 with the intrinsic viscosity [η]. This D0-[η] relationship proves to be very insensitive to polymers structure or solvent type. The data indicate that the ratio of the hydrodynamic radius measured by viscosity to the hydrodynamic radius measured by diffusion is about 15% smaller than that predicted by theoretical models. The nature of the molecular-weight average obtained for polydisperse systems is defined for a Schulz distribution. These hydrodynamic methods have also been used to demonstrate the presence of chain branching in the glycoprotein ovomucoid. In addition, a method is proposed by which the effective segment length and an excluded volume parameter for random coils may be evaluated for diffusion measurements.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150706
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 82
    Digitale Medien
    Digitale Medien
    Conformations of protected oligo(γ-methyl-L-glutamates) at the air-water interface (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1425-1430 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150714
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 83
    Digitale Medien
    Digitale Medien
    The role of alcohols in the polymerization of NCA's by alkaline alkoxides. Dualism of the polymerization mechanism (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1431-1435 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150715
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 84
    Digitale Medien
    Digitale Medien
    Evidence for long-range interactions in DNA. Analysis of melting curves of block polymers d(C15A15)·d(T15G15), d(C20A15)·d(T15G20), and d(C20A10)·d(T10G20) (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1461-1479 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The influence of one DNA region on the stability of an adjoining region (telestability) was examined. Melting curves of three block DNA's, d(C15A15)·d(T15G15), d(C20A15)·d(T15G20), and d(C20A10)·d(T10G20) were analyzed in terms of the nearest neighbor Ising model. Comparisons of predicted and experimental curves were made in 0.01 M and 0.1 M sodium ion solutions. The nearest neighbor formalism was also employed to analyze block DNA transition in the presence of actinomycin, a G·C specific molecule. The results show that nearest neighbor base-pair interaction cannot predict the melting curves of the block DNA's. Adjustments in theoretical parameters to account for phosphate repulsion assuming a B conformation throughout the DNA's do not alter this conclusion. Changes in the theoretical parameters, which provide good overall agreement, are consistent with a substantial stabilization of the A·T region nearest the G·C block. The melting temperature T A·T for the average A·T pari in d(C20A10)·d(T10G20), with 10 A·T pairs, appears to be 4°C greater than TA·T for d(C15A15)·d(T15G15) and d(C20A15)·d(T15G20), both with 15 A·T pairs. Actinomycin bound to the G·C end effectively stabilizes the A·T end by 9°C. These results indicate a long-range contribution to the interactions governing DNA stability. A possible mechanism for these interactions will be discussed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150803
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 85
    Digitale Medien
    Digitale Medien
    Effect of concentration on the aggregation of poly(γ-benzyl-L-glutamate) in dioxane: Critical concentration and maximum length for linear head to tail aggregates (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1543-1554 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dielectric relaxation studies in the frequency range 100 Hz to 2 MHz of poly(γ-benzyl-L-glutamate) in dioxane have been carried out over a range of concentration 10-4-10-2g/g. The structure of aggregates is analyzed in terms of dipole moment and relaxation time. A critical concentration (≃ 10-3 g/g for the studied molecular weights) has been determined below which the aggregates are found to have linear head to tail type structure. Above the critical concentration a different structure of aggregates is apparent which could not be fully analyzed by these measurements alone. Possible forms of aggregation above the critical concentration are discussed. Formation of long range order which would lead to nematic liquid crystalline phase at higher concentrations has been discussed as one of the possible explanations for the observed behavior above the critical concentration.Maximum length of linear head to tail type aggregates for poly(γ-benzyl-L-glutamate) in dioxane as determined from these results correspond to an α-helix of molecular weight 210,000. A slight difference in the purity of dioxane has been shown to have an influence on the reproducibility of the state of aggregation as well as on the rate of disaggregation on dilution.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150809
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 86
    Digitale Medien
    Digitale Medien
    Racemization in the synthesis of sequential polypeptides using N-hydroxysuccinimide esters (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1585-1590 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Racemization in the synthesis of peptide intermediates and their polymers was investigated, using L-amino acid oxidase. The formation of N-hydroxysuccinimide esters from N-protected peptide acids yielded optically pure products in contrast to p-nitrophenyl and pentachlorophenyl active esters. The racemization in the polymerization step was found to be base sensitive. Partially racemized polymer can result from optically homogeneous monomer. Thus, the optical integrity of active monomer species carries no guarantee for that of the polymer.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150812
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 87
    Digitale Medien
    Digitale Medien
    N-methylleucine gramicidin-S and (di-N-methylleucine) gramicidin-S conformations with cisL-Orn-L-N-MeLeu peptide bonds (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1623-1635 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Conformations containing all trans peptide bonds have previously been proposed for N-methylleucine gramicidin-S and (di-N-methylleucine) gramicidin-S based on an evaluation of proton nuclear magnetic resonance parameters in a series of solvents. These gramicidin-S derivatives exhibit full biological activity despite the fact that the proposed solution conformations differ in backbone topology and relative orientation of the Phe and Orn side chains compared to gramicidin-S. The present authors discuss conformations for N-methylleucine gramicidin-S and (di-N-methylleucine) gramicidin-S which incorporate cis peptide bonds at L-Orn-L-N-MeLeu, where the gramicidin-S backbone is essentially retained, and the relative orientation of the Pro, Orn, Val, and Phe side chains correspond to those observed for gramicidin-S. A novel hydrogen-bond arrangement involving one carbonyl group interacting with two peptide protons (1 ←4 and 1 ←5 types) is proposed to stabilize the backbone conformation in the gramicidin-S derivatives. A recent report on the cyclic heptapeptide antibiotic, Ilamycin B1, shows the presence of cis peptide bonds at N-CH3 amino acids, as well as the novel hydrogen-bond arrangement presented above.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150815
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 88
    Digitale Medien
    Digitale Medien
    Conversion of fibrinogen to fibrin. The correlation between clotting kinetics and morphology of fibrin polymerized in different solvent media (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1979-1990 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The morphology of fibrin strongly depends on solvent medium, as shown by clotting experiments carried out in the presence of different salts. The clots were characterized by electron microscopy and spectrophotometric methods; the kinetics of gelation were determined.In the presence of electrolytes which strongly delay clotting, the strands are thin and few branching points are observed; opposite morphological changes are induced by salts which act as accelerating agents. On the basis of this correlation, and of previous data on the structure of fibrin, a kinetic model of the self-assembly process is outlined. It accounts well for the observed solvent effects on the morphology of the network.An important result emerging from our experiments is that the fibers undergo branching prior to gelation. Branching points arise from the defective growth of the fibers; a simple explanation of the occurrence of branching may be obtained by our self-assembly model.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151009
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 89
    Digitale Medien
    Digitale Medien
    The X-Pro peptide bond as an nmr probe for conformational studies of flexible linear peptides (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 2025-2041 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The equilibrium between the cis and trans forms of X-Pro peptide bonds can readily be measured in the 13C nmr spectra. In the present paper we investigate how observation of this equilibrium could be used as an nmr probe for conformational studies of flexible polypeptide chains. The experiments include studies by 13C nmr of a series of linear oligopeptides containing different X-L-Pro peptide bonds, with X = Gly, L-Ala, L-Leu, L-Phe, D-Ala, D-Leu, and D-Phe. Overall the study confirms that X-Pro peptide bonds can generally be useful as 13C nmr probes reporting the formation of nonrandom conformation in flexible polypeptide chains. It was found that the cis-trans equilibrium of X-Pro is greatly affected by the side chain of X and the configuration of the α-carbon atom of X. On the basis of these observations some general rules are suggested for a practical applications of the X-Pro nmr probes in conformational studies of polypeptide chains.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151012
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 90
    Digitale Medien
    Digitale Medien
    Conformational studies in aqueous solution on random copolymers of L-glutamic acid and ortho-nitrobenzyl-L-glutamate. Circular dichroism and potentiometric titration studies (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 2101-2119 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Random copolymers of L-glutamic acid and ortho-nitrobenzyl-L-glutamate were synthesized with different percentages of nitrobenzyl-L-glutamate, from 3 to 22%. These copolymers were studied by circular dichroism (CD) and potentiometric titrations in aqueous solutions in order to determine the variation of the stability of the secondary structure when the concentration of nitrobenzylglutamate varies in the copolymer. We observed that the stability increases with the concentration of glutamate. Such a stabilization could be due to either side-chain interactions or interactions between the aromatic side chain with the backbone. An intermolecular aggregation was observed when the percentage of nitrobenzylglutamate was sufficently important, but such an aggregation may be avoided if a dioxane/water mixture is used as a solvent.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151102
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 91
    Digitale Medien
    Digitale Medien
    Kinetics of γ-benzyl-L-glutamate NCA's polymerizations and molecular-weight distributions on corresponding polymers (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 2185-2199 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The kinetics of γ-benzyl-L-glutamate NCA's polymerizations in dioxane as solvent are discussed. The partial orders respective to [A], the NCA concentration and [I0], the initial initiator concentration are given; the rate constants are deduced and a mechanism is proposed to justify a rate of polymerization Vp = k[A][I0]2.The dependence of the rate constants on the conformation of the growing chains is demonstrated; the acceleration is attributed to the ordered structures favorable to hydrogen bonding. The kinetics of aging have also been examined and discussed; it is shown that they cannot modify the kinetics of polymerization.The DPn were obtained on the same samples before and after debenzylation; it is proved that at any concentration, DPn ≃ [A0]/[I0].The molecular-weight distributions were obtained by chromatography and a polydispersity lower than 1.3 was deduced for each sample. The trimodal distribution, appearing as soon as [A0]/[I0] is larger than 3, is attributed to the existence of the three structures σ, β, and α. The weight fraction of each of the structures was correlated to the kinetics of polymerization.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151107
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 92
    Digitale Medien
    Digitale Medien
    Electron diffraction of Valonia cellulose. A quantitative interpretation (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1903-1915 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The crystal structure of native cellulose (Valonia) has been analyzed by electron diffraction. Possible models for the structure were refined by rigid-body least squares methods, which incorporated parameters defining the preferred orientation of the fibrils around their long axes in the cell wall lamellae. The structure was found to consist of an array of chains having the same sense (i.e., parallel), with packing parameters similar to those recently determined by X-ray diffraction. The eight-chain unit cell could be approximated adequately by a two-chain monoclinic unit cell with dimensions a = 8.18 Å, b = 7.84 Å, c = 10.38 Å (fiber axis), and γ = 97.04°; the space group is P21.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151003
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 93
    Digitale Medien
    Digitale Medien
    Relative stability of the α-helix of deuterated poly(γ-benzyl-L-glutamate) (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1939-1950 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The coil-to-helix transition temperatures of hydrogen bearing and deuterated poly(γ-benzyl-L-glutamate) in 1,3-dichlorotetrafluoroacetone/H2O and/D2O mixtures, respectively, have been determined. Together with previously obtained data for the conformational transition of this polypeptide in normal and deuterated dichloroacetic acid, these results have been used in an analysis of the effect of deuterium substitution on the intrinsic stability of the α-helical form of poly(γ-benzyl-L-glutamate). The findings, consistent for both solvent systems, showed that the deuterated polypeptide is some 5% more stable than the normal protonated poly(γ-benzyl-L-glutamate), while the polypeptide-active solvent interaction enthalpy is also slightly increased by deuterium substitution in the respective molecules. A consideration of available data for poly(β-benzyl-L-aspartate) reveals an anomaly with respect to the present analysis.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151006
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 94
    Digitale Medien
    Digitale Medien
    Electric field-induced conformational change of poly(L-lysine) studied by transient electric birefringence (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1669-1676 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Transient electric birefringence measurements on poly(L-lysine hydrobromide) in methanol-water mixtures have been carried out at various solvent compositions in the vicinity of the helix-coil transition region (from 87 to 98 vol % methanol). Anomalous birefringence transients were observed between 90 and 95 vol % methanol above a threshold field strength. A distinct difference between the responses to weak and strong electric fields was noticed over a narrow range of the solvent composition. The effects of polymer concentration and temperature on the field-strength dependence of the birefringence were studied at a solvent composition of 90 vol % methanol where the anomalous transients appeared most clearly. The double logarithmic plots of the steady-state specific birefringence versus the square of field strength for different concentrations and temperatures could be superimposed by shifting them horizontally along the abscissa. The threshold field strength which was determined from the shift factor decreased with decreasing concentration. The results provide further evidence that strong electric fields can cause a helix-coil transition in this system under favorable conditions.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150904
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 95
    Digitale Medien
    Digitale Medien
    Studies of peptide conformation: Backbone folding of tetrapeptide derivatives in methanol and water (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1701-1715 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Derivatives of tetrapeptide sequences considered likely to form β-turns were investigated by the study of their proton magnetic resonances in methanol and in water. Differential broadening of N - H resonances by an added nitroxyl was used to indicate the presence of the sequestered N - H proton expected in β-turn conformations. Transfer of magnetic saturation from solvent water protons to N - H protons was also examined. The evidence is consistent with significant contributions by β-turn-like backbones to the conformational averages in methanol of the sequences Gly-L-Pro-D-Val-Gly, D(or L)-Val-L-Pro-Gly-Gly, and Gly-L-Pro-L-Asn-Gly, but not the sequence Gly-D-Ala-L-Val-Gly. It is suggested that a Type I turn, Likely in Gly-L-Pro-L-Asn-Gly derivatives, is characterized by sequestered N - H protons of both the third and fourth residues. For all of the peptide derivatives, save possibly Ac-L-Val-L-Pro-Gly-Gly-NHNH2, contributions from folded structures in water are not detectable by line-broadening experiments. However, the transfer of saturation experiments may be interpreted as indicating some degree of chain folding in water.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150908
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 96
    Digitale Medien
    Digitale Medien
    The spatial distribution of moving macromolecules undergoing isomerization (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1717-1739 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In this paper we use probabilistic arguments to derive and discuss the spatial distribution of molecules which are undergoing electrophoresis or centrifugation while at the same time they are switching back and forth between two configurational states. An exact solution is obtained for arbitrary values of the diffusion coefficients of the two isomerizing states. The traditional analytic method of solving this problem, namely, by use of “master equations,” is not completely satisfactory because one can find only the Fourier transform of the solution rather than the solution itself. Our treatment yields the answer one would get if it were feasible to perform the inversion of the Fourier transform.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150909
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 97
    Digitale Medien
    Digitale Medien
    Synthesis of sequential oligopeptides and polypeptide having the sequence of L-alanyl-L-leucylglycine (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1815-1824 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of sequential oligopeptides having simple nonpolar side chains, Nps-(L-Ala-L-Leu-Gly)n- OEt has been prepared by a stepwise fragment-condensation method using Nps-L-alanyl-L-leucylglycine N-hydroxysuccinimide ester, which was prepared by the Nps-N-carboxy α-amino-acid-anhydride method. The success of the synthesis of the peptide having a high-molecular weight, such as octadecapeptide, results from the highest solubility of the tripeptide unit, L-alanyl-L-leucylglycine. The sequential polypeptide having the same tripeptide sequence was also prepared by polycondensation of the tripeptide N-hydroxy-succinimide ester.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150914
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 98
    Digitale Medien
    Digitale Medien
    Comparison of different theoretical descriptions of helix-coil transitions in DNA (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1841-1844 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150917
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 99
    Digitale Medien
    Digitale Medien
    Time-dependent Hartree calcuations of nucleic acid hypochromism (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1873-1875 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360150923
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 100
    Digitale Medien
    Digitale Medien
    Cooperative disordering of single-stranded polynucleotides through copper crosslinking (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1879-1902 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The thermal transitions of single-stranded polynucleotides are noncooperative. In contrast, Cu(II) cooperatively disorders the single-stranded helical structures of poly(A) and poly(C), as demonstrated by ORD and UV spectral changes as a function of the Cu2+ activity, and by a dramatic chain-length dependence of the spectral changes. Equilibrium dialysis binding studies indicate that the cooperative disordering is paralleled by a somewhat less cooperative binding process.The difference between the thermal- and Cu(II)-induced transition is explained by the following mechanism. (1) Cu(II) initially binds in a noncooperative fashion to phosphate. (2) The Cu(II) so bound forms a second bond to a nonadjacent base site on the same polymer strand or another strand. These intramolecular and intermolecular crosslinks to the bases are responsible for the disordering. (3) The initial crosslinks formed provide nuclei for the cooperative formation of additional crosslinks, producing cooperative spectral changes paralleled by cooperative binding.A comparison of the spectral and binding transitions indicates that there is appreciable noncooperative binding of copper to phosphate, which produces no spectral changes in the presence of added electrolyte. This comparison also indicates that each copper crosslink disorders several bases. The formation of intermolecular crosslinks is demonstrated by a polymer concentration dependence of the disordering. The formation of intramolecular crosslinks can be deduced from the fact that the “cooperative unit” required to explain the differences between the hexamer, which does not readily form intramolecular crosslinks, and the polymer is considerably larger than the cooperative unit determined from the polymer results.The poly(A) disordering transition is less symmetrical than that of poly(C), particularly at low polymer concentrations. These results, together with other phenomena, are explained by a greater flexibility of poly(A), which favors the formation of small intramolecular loops.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1976.360151002
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...