bluuebunny/crossref_metadata_2025 huggingface dataset:
CASTELNUOVO‐Regularität und HILBERTreihen
Authors: Nagel Uwe
Published: May 2007

Let A be an equidimensional locally Cohen‐Macaulay graded k‐algebra. Following [16] we have upper bounds for Castelnuovo's regularity of A (see [16], main theorem und theorem 1.). The aim of this paper is to characterize the equalities of these bounds and Castelnuovo's regularity by using the theory of Hilbert series. For this reason the inequalities of [16] are new proved by applying our methods. Moreover, we improve and extend main results and investigations of [11], [7], [18], [14], [16].

For monomial ideals the conjecture of D. BAYER and M. STILLMAN [4] is proved.
Oscillatory and Asymptotic Behavior of Damped Functional Differential Equations
Authors: Grace S. R.
Published: May 2007

New theorems on the oscillatory and asymptotic behavior of solutions of the damped differential equations with deviating arguments of the form

are established.
An Iterative Variant of the Degenerate Kernel Method for Solving Fredholm Integral Equations
Authors: Moret Igor , Omari Pierpaolo
Published: May 2007

An iterative variant of the classical degenerate kernel method for solving Fredholm integral equations of the second kind is presented and its convergence properties are studied.
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Authors: [Russian Text Ignored.]  , [Russian Text Ignored.]
Published: May 2007

[Russian Text Ignored.]
Bewertungen von Limesräumen
Authors: Weber K. , Filter W.
Published: May 2007

The first aim of this paper is to characterize those limit spaces (X, τ) which can be valuated, i.e. for which a set E of valuations exists such that for each x ∈ X, τ(x) equals the set of filters on X which converge to x relative to E. It is shown further that a separated pretopological space is a URYSOHN‐space iff it can be valuated by a set of subadditive valuations. In the second part of the paper a completion is constructed for the separated subadditively valuated limit spaces which can be considered as a generalization of the usual completion of a uniform space.
L‐Fuzzy Contiguity Relations and L‐Fuzzy Closure Operators in the Case of Completely Distributive, Complete Lattices L
Authors: Flüshöh Wolfgang , Höhle Ulrich
Published: May 2007

In the case of completely distributive, complete lattices L the relations between L‐fuzzy contiguity relations and L‐fuzzy closure operators are investigated. In addition, if L is the real unit interval, L‐fuzzy contiguity relations are represented by means of VD‐contiguity relations, PT spaces and random VD‐contiguity relations respectively.
The Commutant of the Laplace Operator in Lp(R)
Authors: Ricker Werner J.
Published: May 2007

Let L = ‐ d2/dx2 be the Laplace operator in Lp(R), 1<p < ∞. It is shown that a bounded operator T in Lp(R) commutes with L, in the sense that the domain D of L is T‐invariant and TLf = LTf for each f in D, if and only if T commutes with all (bounded) multiplier operators corresponding to symmetric p‐multipliers on R. The bicommutant L consists of all the symmetric p‐multiplier operators.
A Locally Convex Extremal Problem over Some Family of Complex Functions
Authors: Baranowicz Józef , Studniarski Marcin
Published: May 2007

We shall be concerned in this paper with mathematical programming problem of the form: Φ0(f) → min subject to Φi(f) ≦ 0, i = 1, 2, …, r; f where Φi(f), i = 0, 1, …, r are regularly locally convex functions is a family of complex functions that possesses an integral representation. For this problem a necessary condition for a local minimum is given.
Special Additive and Multiplicative Commutator Representations for Diagonal Operators
Authors: Scholz E. , Timmermann W.
Published: May 2007

Let 𝒟 be a dense linear subspace of a separable Hilbert space and let ℒ︁+(𝒟) be the maximal Op*‐Algebra on 𝒟. The paper deals with a class of diagonal operators of ℒ︁+(𝒟), for which we can prove some results concerning special commutator representations. For this end ideas of [1] are generalized.
Factorization and Extrapolation of Pairs of Weights in Two Different Measure Spaces
Authors: Ruiz Francisco J. , Torrea José L.
Published: May 2007

The technique introduced by RUBIO DE FRANCIA ([13], [14]) in order to obtain factorization and extrapolation results for Ap weights is used here in a more general setting in which can appear two different measure spaces and two different operators.
Stratonovich and Ito Stochastic Taylor Expansions
Authors: Kloeden P. E. , Platen E.
Published: May 2007

The Stratonovich stochastic Taylor formula for diffusion processes is stated and proved. It has a simpler structure and is a more natural generalization of the deterministic Taylor formula than the Ito stochastic Taylor formula.
On the Structure of Entrance Laws in Discrete Spatial Critical Branching Processes
Authors: Wakolbinger Anton
Published: May 2007

MARKOVian branching population‐valued stochastic processes in discrete time are considered, in which the individuals live on a discrete space of sites and an individual at site x produces, independently of the others, in the next generation a random offspring whose distribution depends on x, whose mean total number is assumed to be one and whose mean number at site y is denoted by J(x, [y]). It is proved that, provided the MARKOV chain associated with the transition matrix J is null‐recurrent, exactly those among the entrance laws for the population‐valued process are extremal and have a finite mean number of individuals at any site and time, which are „of POISSON type”︁, i.e. arise in a natural way from a POISSONian remote past. This generalizes a result of LIGGETT/PORT [3] on the pure motion case to the case of branching, and also comments on a remark of DYNKIN ([1], p. 110).
On the Intersection Density of Flat Processes
Authors: Mecke J.
Published: May 2007

Stationary POISSON r‐flat processes in the d‐dimensional Euclidean space (d/2 ≦ r ≦ d − 1) induce a process of (2r − d)‐flats each of which is the intersection of two r‐flats of the original processes. The intensity of the induced (2r − d)‐flat process is called intersection density of the original POISSON r‐flat process. The problem of maximizing the intersection density for given intensity is considered. A new approach to earlier results of THOMAS and the author is presented.
Self‐Similar Random Measures III – Self‐Similar Random Processes
Authors: Zähle U.
Published: May 2007

This is the last paper of my husband. He wrote it in September 1989 and was no more able to prove the manuscript and to add an introduction. Therefore I have tried now to do this for him hoping that the message will be understood.
Nonvertical Affine Manifolds and Separation Theorems in Product Spaces
Authors: Thierfelder Jörg
Published: May 2007

In the paper we introduce a general separation concept for sets in product spaces X × Z, where Z is partially ordered. Using some results about nonvertical affine manifolds we formulate some concerte separation theorems. Especially, we get assertions about the separation of sets by affine mappings, in which the order relation “≦” is replaced by the relation „⦔”︁. Thus, these assertions are suitable to characterize PARETO optimal solutions of vector optimization problems.
Boundary Value Problems for Partial Differential Equations in the Plane Revisited
Authors: Mshimba Ali Seif
Published: May 2007

Both boundary value problems the DIRICHLET and the RIEMANN‐HILBERT problems, were solved by the author in the SOBOLEV space W1,p(D), 2 < p < ∞, for the elliptic differential equation in [8], [11] and [12]. In fact in most of the literature so far it is the case of p > 2 only which has been studied extensively. The results obtained so far relied on the fact that the VEKUA‐type operator TD maps the LEBESGUE space Lp(D) Into the HÖLDER space (D̄) for α= (p–2)/p. By modifying both VEKUA type singular integral operators TD and πD it is shown here that we can then solve both boundary value problems in W1,p(D) for 1 < p < ∞. While enlarging the set of admissible SOBOLEV spaces, the set of partial differential equations that can then be solved is reduced through stricter conditions on the LIPSCHITZ constants.
On the Fourier‐Coefficients of Vector‐Valued Functions
Authors: König Hermann
Published: May 2007

We study the decay of the Fourier‐coefficients of vector‐valued functions F : T → X, X a Banach space. Differentiable functions f generally have absolutely summable Fourier‐coefficients, f (n) <, iff X is K‐convex. More precise statements on the decay of f (n) for regular functions f can be given if X has Fourier‐type p. If f belongs to the Besov space, the sequence (||f(n)||) belongs to the Lorentz sequence space lt,v with 1/t = λ + 1/max (u′, p′). This result is the best possible in the vector‐valued case and generalizes the well‐known scalar results.
Γ‐Inequalities and Stability of Generalized Extremal Convolutions
Authors: Dolecki S. , Guillerme J. , Lignola M. B. , Malivert C.
Published: May 2007

Convergence properties of convolutions, conjugations, compositions and polarities are expressed in terms of inequalities involving Γ‐operators and generalized extremal convolutions. It is shown that Γ‐inequalities amount to simple algebraic inequalities and (in some cases) to some min‐max problems. Numerous applications are indicated, in particular, to continuity properties of the classical conjugation.
Linear Fredholm Integral Equations of the 2ndKind with Weakly Correlated Influences on Kernel and Forcing Functions
Authors: Fellenberg Benno , Vom Scheidt Jürgen
Published: May 2007

In der Arbeit werden lineare FREDHOLMSche Integralgleichungen der Form betrachtet.
Periodic Spline Interpolation on Uniform Meshes
Authors: Szyszka Uwe
Published: May 2007

We examine the interpolation with periodic polynomial splines of degree d and defect r (d ≦ r) on equidistant partitions of the real axis and generalize known results for r = 0. We prove necessary and sufficient conditions for the existence and a certain L2‐stability of the interpolants as well as their approximation properties in the scale of the periodic SOBOLEV spaces.
The Analytic Functionals in the Lower Half Plane as a Gel'fand‐Shilov Space
Authors: Duran Antonio J.
Published: May 2007

In this paper we introduce the space (related to the space of GUEL'FAND SHILOV) S+01 of f functions f in (0, + ∞) which satisfy sup tkf(n)(t)| < CAkBnkk for all n, k > 0 and certain C, A, B > O. We study the expansions of the elements of S+01 and those of its dual (S+01)′ with respect to the LAGUERRE orthonormal system, characterizing the sequences of FOURIER‐LAGUERRE coefficients which appear in these expansions. Also, we study the FOURIER transform, proving that it is an isomorphism from the space (S+01)′ onto the space of analytic functions in the lower half plane. We deduce that the space S+01 can be obtained by applying the FOURIER transform to the analytic functionals in the lower half plane. Some applications are given. Finally, we prove that if the spaces S+βα, are defined in (0, + ∞) in a similar way to the spaces of GEL'FAND‐SHILOV (for α, β 0), then, assumed Sβα = {0}, S+βα = {0} holds only for β = 0, α = 1.
The Spectrum of the Dirac Operator on the Hyperbolic Space
Authors: Bunke Ulrich
Published: May 2007

We represent the real hyperbolic space Hn as the rank one homogeneous space Spin (1, n)/Spin (n) and the spinor bundle S of H as the homogeneous bundle Spin (1, n) xSpin (n)VΔ where VΔ is the spinor representation space of Spin (n). The representation theoretic decomposition of L2(H, S) combined with the PARTHASARATHY formula for the DIRAC operator D yields the spectral representation of D2.
On a‐Posteriori Error Estimate of Approximate Solutions to a Mildly Nonlinear Nonpotential Elliptic Boundary Value Problem
Authors: Weisz Juraj
Published: May 2007

The paper deals with the construction of a computable a‐posteriori error estimate of the approximate solution to some nonpotential nonlinear elliptic boundary value problems. The convergence of the presented error estimate to the true error is proved. The method is illustrated on some numerical examples.
The KRÄTZEL Integral Transformation of Distributions
Authors: Barrios Javier A. , Betancor Jorge J.
Published: May 2007

In this paper we define an integral transformation, introduced by E. KRÄTZEL and denoted by Σ that is an extension of the LAPLACE transformation in certain spaces of generalized functions. We employ a procedure based on adjoint operators. We first show that the classical integral transformation is an isomorphism between two new FRÉCHET function spaces. Later the generalized Σ transformation is defined over the corresponding dual spaces as the adjoint of the classical transform. The MELLIN integral transformation is a very useful tool in our study.
The Sampling Theorem, DIRICHLET Series and BESSEL Functions
Authors: Klusch Dieter
Published: May 2007

Generalized forms of the classical WHITTAKER‐KOTELNIKOV‐SHANNON sampling theorem and of the extended BUTZER‐SPLETTSTÖSSER‐STENS sampling expansion for nonbandlimited signal functions are deduced from the famous functional equation of RIEMANN'S zeta‐function and from the well known NIELSEN‐DOETSCH summation formula for BESSEL functions. Hence a rather surprising connection between fundamental theorems of signal analysis and the theories of DIRICHLET and SCHLÖMILCH series is established.
Discontinuous Measure‐Valued Branching Processes and Generalized Stochastic Equations
Authors: Méléard Sylvie , Roelly Sylvie
Published: May 2007

We study a class of integrable and discontinuous measure‐valued branching processes. They are constructed as limits of renormalized spatial branching processes, the underlying branching distribution belonging to the domain of attraction of a stable law. These processes, computed on a test function f, are semimartingales whose martingale terms are identified with integrals of f with respect to a martingale measure. According to a representation theorem of continuous (respectively purely discontinuous) martingale measures as stochastic integrals with respect to a white noise (resp. to a POISSON process), we prove that the measure‐valued processes that we consider are solutions of stochastic differential equations in the space of L2 (Ω)‐valued vector measures.
A Combination Method for Local Bifurcation from Characteristic Values with Multiplicity
Authors: Tan Nguyen Xuan
Published: May 2007

A combination of the LIAPUNOV‐SCHMIDT procedure, the implicit function theorems and the topological degree theory is used to investigate bifurcation points of equations of the form T(v) = L(λ, v) + M(λ, v), (λ, v) ϵ A × D̄, where A is an open subset in a normed space and for every fixed λ ϵ A, T, L(λ ·) and M(λ ·) are mappings from the closure D̄ of a neighborhood D of the origin in a BANACH space X into another BANACH space Y with T(0) = L(λ, 0) = M(λ, 0) = 0.

Let Λ be a characteristic value of the pair (T, L) such that T − L( λ,·) is a FREDHOLM mapping with nullity p and index s, p > s ≧ 0. Under suitable hypotheses on T. L and M, (λ, 0) is a bifurcation point of the above equations. This generalizes the results of [4], [6], [8], [13] and [14] etc. An application of the obtained results to the axisymmetric buckling problem of a thin spherical shell will be given.
Asymptotic Normality of the Vertex Degree in Random Subgraphs of the n‐Cube
Authors: Konieczna Urszula
Published: May 2007

We consider two types of random subgraphs of the n‐cube. For these models we study the asymptotic behaviour of the number of vertices of degree d.
Calkin Representations of Unbounded Operator Algebras Acting on Non‐Separable Domains
Authors: Kürsten Klaus‐Detlef , Milde Michael
Published: May 2007

There are constructed representations of unbounded operator algebras which generalize representations of B(H) constructed by J. W. CALKIN and H. BEHNCKE. For a large class of unitary spaces D, each uniformly closed two‐sided ideal of the maximal Op*‐algebra L+ (D) appears as kernel of such a representation. Irreducibility of the representations is characterized in terms of properties of ultrafilters which define the representations.
Weak Solutions of Deterministic and Stochastic Linear Functional Equations in HILBERT Spaces
Authors: Tudor Constantin
Published: May 2007

In the paper it is shown that weak solutions of linear deterministic and stochastic retarded equations in HILBERT spaces are given by a variation of constants formula. Also, in the deterministic case, a characterization of the unbounded operator appearing in the term without delay is given.
Derivations on LMC*‐Algebras
Authors: Becker R.
Published: May 2007

It is shown that derivations on LMC*‐algebras are always continuous and generate a continuous one‐parameter group of automorphisms. The structure of the derivation and the automorphism group on LMC*‐algebras is investigated.
Imaging mass spectrometry
Authors: McDonnell Liam A. , Heeren Ron M.A.
Published: April 2007

Imaging mass spectrometry combines the chemical specificity and parallel detection of mass spectrometry with microscopic imaging capabilities. The ability to simultaneously obtain images from all analytes detected, from atomic to macromolecular ions, allows the analyst to probe the chemical organization of a sample and to correlate this with physical features. The sensitivity of the ionization step, sample preparation, the spatial resolution, and the speed of the technique are all important parameters that affect the type of information obtained. Recently, significant progress has been made in each of these steps for both secondary ion mass spectrometry (SIMS) and matrix‐assisted laser desorption/ionization (MALDI) imaging of biological samples. Examples demonstrating localization of proteins in tumors, a reduction of lamellar phospholipids in the region binding two single celled organisms, and sub‐cellular distributions of several biomolecules have all contributed to an increasing upsurge in interest in imaging mass spectrometry. Here we review many of the instrumental developments and methodological approaches responsible for this increased interest, compare and contrast the information provided by SIMS and MALDI imaging, and discuss future possibilities. © 2007 Wiley Periodicals, Inc., Mass Spectrom. Rev.
Messunsicherheit in der Werkstoffprüfung
Authors: Polzin T. , Nowaczyk D. , Tscheuschner R. , Worch A.
Published: April 2007

Bei der Werkstoffprüfung muss bei jedem Messwert die jeweilige Messunsicherheit angegeben werden. Aus der 1995 erschienenen GUM [1] wurde 2000 der Uncert Report für verschiedenen Messverfahren entwickelt und als Code of Practice (COP) [2–4]. veröffentlicht. Diese sollen in Zusammenhang mit den in den Normen empfohlenen Verfahren und der praktischen Umsetzung dargestellt werden.
Multiple mechanisms of Erbb2 action after ultraviolet irradiation of the skin
Authors: Madson Justin G. , Hansen Laura A.
Published: May 2007

Ultraviolet (UV) irradiation causes multiple pathologic changes in the skin including inflammation, immune suppression, photoaging, and cancer. Effects of UV irradiation include the activation of numerous signal transduction pathways, including the mitogen‐activated protein kinases (MAPK), and the activation of transcription factors such as nuclear factor kappa B (NFκB). These responses alter gene expression in a manner that resembles the response to growth factors known as the “UV response”. The UV response alters the kinetics of cell division and cell death allowing the skin to recover from the DNA damage caused by UV exposure. UV irradiation also rapidly activates epidermal growth factor receptor (EGFR) family members, including Erbb2 (human epithelial growth factor receptor 2 (HER2)/neu), through the generation of reactive oxygen species. Erbb2, a protooncogene that is activated in many types of cancer and associated with aggressive and chemotherapeutic‐resistant disease, is expressed in both follicular and epidermal keratinocytes within the skin. However, the physiological functions of Erbb2 in the skin and its role in the UV response are largely unknown. In this review, evidence that Erbb2 is influential in modulating the response of the skin to UV will be presented. Erbb2 alters the expression of regulatory genes controlling inflammation, angiogenesis, cell division, apoptosis, cell adhesion, and migration following UV irradiation. In addition, Erbb2 dampens UV‐induced S‐phase arrest, augments inflammation in response to UV irradiation, and suppresses UV‐induced apoptosis. In summary, the evidence presented herein links UV‐induced Erbb2 activation to many of the effects of UV and implicates Erbb2 in UV‐induced carcinogenesis. © 2007 Wiley‐Liss, Inc.
Distinct roles of individual Smads in skin carcinogenesis
Authors: Bornstein Sophia , Hoot Kristina , Han Gang‐Wen , Lu Shi‐Long , Wang Xiao‐Jing
Published: May 2007

Transforming growth factor β (TGFβ) signaling has both tumor suppression and promotion roles. Smads are transcription factors that primarily mediate intracellular signaling for the TGFβ superfamily. Loss of Smad2 and Smad4, but not Smad3 is common in human cancers. Given the complex nature of TGFβ signaling, dissection of the distinct role of each Smad in mediating the multiple functions of TGFβ signaling is warranted. To further analyze Smad deregulation during carcinogenesis, Smad2, Smad3, Smad4, and Smad7 were genetically modified in murine epidermis, and each alteration resulted in distinct skin phenotypes. Based on data from human cancer samples and from experimental models, Smad2 and Smad4 mainly function as tumor suppressors in skin carcinogenesis in vivo, whereas Smad3 and Smad7 may have dual roles in cancer. This review intends to summarize recent advances in the elucidation of the roles of Smad2, Smad3, Smad4, and Smad7 in skin carcinogenesis. © 2007 Wiley‐Liss, Inc.
Training program and learning curve in experimental microsurgery during the residency in plastic surgery
Authors: Lascar Ioan , Totir Dumitru , Cinca Adrian , Cortan Silviu , Stefanescu Andrei , Bratianu Raluca , Udrescu George , Calcaianu Nicolae , Zamfirescu Dragos G.
Published: May 2007

This article presents a comparison of microsurgical training of groups with different background. A protocol based on the rat femoral arterial anastomoses was used to provide an objective representation of the microsurgical skills progress. The performance is assessed by consistent (×4) patency of a standardized anastomosis. Three groups of beginner residents with progressive microsurgical experience and one group of experienced surgeons were observed. The patency curve of the beginner‐groups was as an abrupt learning curve, and then a plateau was reached. There was no statistically significant difference in the patency rate between the beginner‐groups after their first 32 anastomoses. No statistically significant difference was noted when the patency of the advanced group was compared with beginner‐groups after different numbers of anastomoses (inverse proportional with their training experience). A slight or a plateau learning curve was found among the experienced group. The learning curve is a useful adjunct in the assessment of training. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Spleen autotransplantation. Morphological and functional follow‐up after spleen autotransplantation in mice: A research summary
Authors: Miko Iren , Brath Endre , Nemeth Norbert , Furka Andrea , Sipka Sandor , Peto Katalin , Serfozo Jozsef , Kovacs Judit , Imre Sandor , Benko Ilona , Galuska Laszlo , Sipka Sandor , Acs Geza , Furka Istvan
Published: May 2007

In 1986, we started the research on spleen surgery aimed at saving the splenic mass after its traumatic injury, with elaboration of special resection and autotransplantation techniques. The researches started on mongrel dogs and were continued on inbred mice and beagle dogs with complex histological, imaging, and laboratory investigations, following‐up the function and the regeneration of autotransplanted spleen chips. Performing research on mice provided more immunological methods, such as lymphocyte subsets, immunoglobulin levels, and monitoring the phagocytic functions. Researches showed evidence also on the presence of apoptosis, furthermore, stem cell studies on regeneration and functional restoration of the spleen chips are in progress. Our results contributed to two multidisciplinary guidelines in Hungary: (1) One of them is under preparation and underlines the importance of spleen saving methods after traumatic splenic injury; (2) The second guideline shows that hemorheological changes can be early indicators of the increased sensitivity to postsplenectomy infections. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Improved cuff technique for cervical heart transplantation in mice
Authors: Gu Xiaodong , Xiang Jianbin , Zhou Yiming , Qian Shiguang , Chen Zongyou
Published: May 2007

To simplify the surgical procedure and increase the postoperative survival rate, an improved cuff technique was developed for cervical heart transplantation in mice. Forty cervical heart transplants have been performed in mice with a success rate of 92.5%. The total operative time was within 60 min, and the cold ischemic time for the graft hearts was minimized to less than 30 min. The improved cervical heart transplantation in mice by modified cuff technique is a practical and reliable animal model and can be done by surgeons with a little microsurgery experience. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Cotransplanted hepatic stellate cells enhance vascularization of islet allografts
Authors: Yin Zhenyu , Wu Wenhan , Fung John J. , Lu Lina , Qian Shiguang
Published: May 2007

Islet transplantation is an alternative to whole pancreas transplantation in curative therapy of diabetics. The outcome of engraftment of islet, however, remains disappointing. Rapid and adequate islet revascularization is crucial for the survival and function of transplanted islets. In this study, hepatic stellate cells (HSC) were cotransplanted with islet allografts, achieving marked prolongation of islet allografts. This was associated with enhanced revascularization within islet grafts as determined by anti‐CD31 antibody staining. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Review of vascularized bone marrow transplantation: Current status and future clinical applications
Authors: Gordon Chad R. , Tai Chau Y. , Suzuki Hidetoshi , Strande Louise F. , Ramsamooj Rajendra , Matthews Martha S. , Black Kirby S. , Hewitt Charles W.
Published: May 2007

In this review, we examine the applicability of the vascularized bone marrow transplant (VBMT) as an alternative to conventional bone marrow transplantation (BMT). As a new surgical approach, the VBMT is unique by transplantation of the stromal environment that eliminates the need for an engraftment period, provides critical signaling and modulatory functions, and may potentiate tolerance induction. Thus far, VBMT studies have demonstrated an absence of graft‐versus‐host disease (GVHD) and robust engraftment into nonmanipulated as well as irradiated recipients with evidence of immunological tolerance. Further investigation is needed to determine the applicability of VBMT as an alternative to BMT. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Elastic–ideally plastic beams and Prandtl–Ishlinskii hysteresis operators
Authors: Krejčí Pavel , Sprekels Jürgen
Published: May 2007

The one‐dimensional equation for transversal vibrations of an elastoplastic beam is derived from a general three‐dimensional system with a single‐yield tensorial von Mises plasticity model. It leads after dimensional reduction to a multiyield scalar Prandtl–Ishlinskii hysteresis model whose weight function is explicitly given. The use of Prandtl–Ishlinskii operators in elastoplasticity is thus not just a questionable phenomenological approach, but in fact quite natural. The resulting partial differential equation with hysteresis is transformed into an equivalent system for which the existence and uniqueness of a strong solution is proved. The proof employs techniques from the mathematical theory of hysteresis operators. Copyright © 2007 John Wiley & Sons, Ltd.
Fight for fair play
Authors: Hanson Royce
Published: May 2007

Aroused Maryland voters, unable to secure just legislative representation, organize for action.
Museums for civics
Authors: Goldman Ralph M.
Published: May 2007

Proposal envisions exhibits tracing origin, development and processes of government.
Are the cities broke?
Authors: Cleveland Harlan
Published: May 2007

Mayors told to quit griping about rural, U. S. hurdles and to master own financial problems.
Cities to doughnuts
Authors: Gruen Victor
Published: May 2007

Dying downtowns can be revived, says planner, only by comprehensive, integrated approach.
Communities and floods
Authors: Gray Aelred J.
Published: May 2007

Rapid urban growth emphasizes need for long range planning in previously affected areas.
The rebirth of kiel
Authors: Greene Thomas
Published: May 2007

City's destruction in World War II a blessing in disguise in giving it opportunity to plan anew.
Seek transit solution
Authors: Mantel Howard N.
Published: May 2007

Experiment in Washington, D. C., area may prove a model for action in other metropolitan regions.
Mood of the people
Authors: Kreutzer S. Stanley
Published: May 2007

New York City Code of Ethics reflects desire for serious, mature standards of public conduct.
Linear time algorithms for approximating the facility terminal cover problem
Authors: Xu Guang , Yang Yang , Xu Jinhui
Published: May 2007

In this paper, we consider an interesting generalization of the weighted vertex cover problem, called the Facility Terminal Cover (FTC) problem. In the FTC problem, each vertex is associated with a positive weight, each edge is associated with a positive demand, and the objective is to determine a subset of vertices and a capacity for each selected vertex so that the demand of each edge is covered by the capacity of one of its two endpoints and the total weighted capacity of all selected vertices is minimized. The FTC problem is motivated by several key network optimization problems, such as the power assignment problem in ad hoc networks, and could be used as a subroutine to solve such problems. No quality‐guaranteed solution is previously known for the FTC problem. In this paper, we present two linear time approximation algorithms for this problem. Our first algorithm achieves deterministically an approximation ratio of 8 by using an interesting rounding technique and a lower‐bounding technique. Based on interesting randomization techniques, our second algorithm further improves the approximation ratio to 2e, whereeis the natural logarithmic base. The second algorithm can be easily derandomized in quadratic time. Our algorithms are relatively simple and can be easily implemented for networking applications. Experiments show that the two algorithms behave rather similarly, especially in large‐size graphs, indicating that the solutions yielded by one or both algorithms are much closer to the optimum. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(1), 118–126 2007
Toward realization of computational homogenization in practice
Authors: Yuan Zheng , Fish Jacob
Published: May 2007

We present a computational homogenization approach for linear and non‐linear solid mechanics problems, which is fully compatible with conventional finite element code architecture. A seamless implementation in ABAQUS is presented including Python script, validation problems and a web‐link where script files, user‐defined subroutines and input files can be accessed. For linear problems, we demonstrate how to utilize ABAQUS existing facilities to develop analysis attributes required for solving a unit‐cell problem. For non‐linear problems, a Python script invoked by a coarse‐scale stress update procedure is introduced to carry out the scale bridging. The purpose of this paper is twofold: (i) to motivate practitioners to adopt the computational homogenization as an integral part of their analysis and design process; and (ii) to encourage commercial code vendors to seamlessly integrate the architectures proposed in their legacy codes. Copyright © 2007 John Wiley & Sons, Ltd.
A heterogeneous space–time full approximation storage multilevel method for molecular dynamics simulations
Authors: Waisman Haim , Fish Jacob
Published: May 2007

A heterogeneous space–time full approximation storage (HFAS) multilevel formulation for molecular dynamics simulations is developed. The method consists of a waveform Newton smoothing that produces initial space–time iterates and a coarse model correction. The formulation is coined as heterogeneous since it permits different interatomic potentials to be applied at different physical scales. This results in a flexible framework for physics coupling. Time integration is performed in windows using the implicit Newmark predictor–corrector method that permits larger time integration steps than the explicit method. The size of the time steps is governed by accuracy rather than by stability considerations of the algorithm. We study three different variants of the method: the Picard iteration, constrained dynamics and force splitting. Numerical examples show that FAS based on force splitting provides significant time savings compared to standard explicit methods and alternative implicit space–time schemes. Parallel studies of the Picard iteration on harmonic problems illustrate the time parallelization effect that leads to a superior parallel performance compared to explicit methods. Copyright © 2007 John Wiley & Sons, Ltd.
Characterisation of glucosinolates using electrospray ion trap and electrospray quadrupole time‐of‐flight mass spectrometry
Authors: Fabre Nicolas , Poinsot Véréna , Debrauwer Laurent , Vigor Claire , Tulliez Jacques , Fourasté Isabelle , Moulis Claude
Published: May 2007

Twelve naturally occurring glucosinolates displaying alkenyl, hydroxylated, methylsulphinyl, aromatic and indole side chains were investigated by both negative and positive ion electrospray ionisation–tandem mass spectrometry (ESI‐MS/MS). In order to resolve the MS/MS spectra obtained from the anion and cation molecular ions of glucosinolates, the different fragments were investigated by MSn experiments using an ion trap spectrometer. The MS3 spectra obtained permitted possible fragmentation schemes to be proposed. These were supported by accurate mass measurements of some characteristic diagnostic ions with the help of a quadrupole time‐of‐flight instrument. The negative ion ESI‐MS/MS behaviour of the different glucosinolates investigated in this study confirmed previously described patterns and revealed new interesting structural informative fragments. Some are common to all the glucosinolates and others are highly specific for a type of variable side chain. The positive ion ESI‐MS/MS fragments obtained from the [MNa + Na]+ or [MK + K]+ molecular ions did not provide complementary specific diagnostic ions. Nevertheless, when compared with the negative ion mode, the daughter ions appeared more homogenous and with a better relative abundance for all of the 12 compounds studied. Moreover, the positive ion mode appeared to be more efficient than the negative mode for the study of methoxylated glucosinolates and should be useful to detect the glucosinolates present as organic salts in crude plant extracts. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of saponins in the kernel cake of Balanites aegyptiaca by HPLC‐ESI/MS
Authors: Chapagain Bishnu P. , Wiesman Zeev
Published: May 2007

The kernel cake produced from Balanites aegyptiaca fruit of Israeli origin was analysed for its saponin constituents using high‐performance liquid chromatography–mass spectrometry (HPLC‐MS). The HPLC was equipped with a reversed‐phase C18 column and a refractive index detector (RID), and elution was isocratic with methanol and water (70:30). The MS system was equipped with electrospray ionisation (ESI). Nine compounds were chromatographically separated, their masses were determined in the negative ion mode and subsequent fragmentation of each component was carried out. From the nine components, six saponins with molecular masses of 1196, 1064, 1210, 1224, 1078 and 1046 Da were identified, with the compound of mass 1210 Da being the main saponin (ca. 36%). Saponins with masses of 1224 and 1046 Da have not been previously reported in B. aegyptiaca. In all saponins, diosgenin was found to be the sole aglycone. This study shows that HPLC‐ESI/MS is a quick and reliable technique for characterizing the saponins from kernel cake of B. aegyptiaca. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental study on tensioned‐web slot coating
Authors: Lin Fang‐Ho , Liu Chi‐Ming , Liu Ta‐Jo , Wu Ping‐Yao
Published: April 2007

Tensioned‐web slot coating (TWSC) technology was developed in the early 1980s and was considered an efficient method for thin liquid film coating. An experimental study was carried out to investigate the effects of several key parameters on the minimum wet thickness of TWSC. The experiment was performed on a pilot coater with dilute Newtonian poly(vinyl) alcohol (PVA) solutions as test fluids coating on polyethylene‐terephthalate (PET) substrates. It was found that the minimum wet thickness for TWSC was between 0.5 and 1.5 μm, which is much lower than that obtained using conventional slot die coating. The minimum wet thickness was proportional to the tension number TN, which is defined as the ratio of fluid viscous force over web tension. Furthermore, on the basis of the experimental data, two additional dimensionless groups: dimensionless pressure PN and dimensionless surface tension LN were found to be relevant to the performance of TWSC. A universal correlation involving these dimensionless groups as well as the die geometry was used to predict the minimum wet thickness of TWSC. POLYM. ENG. SCI., 47:841–851, 2007. © 2007 Society of Plastics Engineers
Nanovoid relaxation in a series of copolyester glasses under cyclic loading using synchronous PALS
Authors: Sun Nanjian , Liu Jianwei , Dull Terry , Yee Albert F.
Published: May 2007

This study examines if correlation between a specific molecular motion and the growth and relaxation of nanovoids, which are precursors to crazes, can be established. A novel technique, positronium annihilation lifetime spectroscopy (PALS) synchronized with cyclic stress, is reported. In this technique the positronium annihilation signal was accumulated in sixteen channels corresponding to sixteen phases of the sinusoidal load, which allowed statistically significant data for nanovoid generation and relaxation due to the fluctuating stress to be accumulated. This technique was applied to a series of copolymers of poly(ethylene terephthalate) (PET) and poly(1,4‐cyclohexylenedimethylene terephthalate) (PCT). Previous studies have shown that the cyclohexylene rings in the main chain of PCT actively undergo chair‐boat‐chair conformational transitions in the glassy PCT at around room temperature. The PET‐co‐PCT series was also chosen for this study because the crazing stress increases systematically with the cyclohexylene content. The synchronized PALS data are consistent with the hypothesis that transient nanovoids generated by the cyclic stress in polymers containing more cyclohexylene rings relax more readily than those with fewer rings. The results also correlate well with the crazing stress in this series of copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1410–1417, 2007
Mechanical properties and inhomogeneous nanostructures of dicyandiamide‐cured epoxy resins
Authors: Kishi Hajime , Naitou Takemi , Matsuda Satoshi , Murakami Atsushi , Muraji Yuichi , Nakagawa Yoshitsugu
Published: May 2007

Dicyandiamide (DICY)‐cured epoxy resins are important materials for structural adhesives and matrix resins for fiber reinforced prepregs. The objective of this study was to examine the mechanical and physical properties as well as the gel structures of the cured resins and discuss the relationships among them. Diglycidyl ether of bisphenol‐A (DGEBA) oligomers were chosen as the common chemical structure of the epoxy resins. Four kinds of resin mixtures were formulated using the seven types of DGEBA oligomers having different molecular weight distributions. Three resin formulations having bimodal‐type molecular weight distributions were designed to have almost identical rubbery plateau values of the storage modulus in dynamic mechanical analyses after curing, means that they had almost equivalent average crosslink density and basic chemical structure. However, the toughness, ductility, and environmental (heat and solvent) resistance of these three formulations were different. Atomic force microscopy revealed the existence of inhomogeneous nanoscale gel structures in these cured resins. The morphological differences in the gel structures in terms of their size, the connectivity, and the relative magnitude of the heterogeneity would cause the difference in several properties of the DICY‐cured epoxy resins. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1425–1434, 2007
Inhibition of fatty acid synthase activity in prostate cancer cells by dutasteride
Authors: Schmidt Lucy J. , Ballman Karla V. , Tindall Donald J.
Published: May 2007

PURPOSE

With malignant progression to androgen independence, prostate cancer cells develop resistance to apoptosis and exhibit a variety of gene expression changes, including increased fatty acid synthase (FASN) expression. Increased FASN expression has been shown to correlate with poor prognosis, and correspondingly, the FASN gene has been proposed as a therapeutic target. Because FASN is an androgen regulated gene in the prostate, we have examined the effects of dutasteride on FASN in prostate cancer cells in vitro. Dutasteride is a novel dual inhibitor of the 5 alpha‐reductase enzymes and is currently in use both for treatment of benign prostate hyperplasia (BPH) and in the reduction by dutasteride of prostate cancer events (REDUCE) prostate cancer prevention trial.

METHODS

Microarray analysis was used to identify genes affected by treatment with dutasteride, followed by real time PCR confirmation. FASN expression at the protein level was examined using Western blotting and immunocytochemistry. Enzymatic activity of FASN was assayed by 14C‐labeled malonyl‐CoA incorporation. Viability after dutasteride treatment was assayed by MTS (Promega) and apoptosis via caspase 3/7 by DEVD cleavage assay.

RESULTS

We have demonstrated that the 5 alpha‐reductase inhibitor dutasteride, at clinically relevant levels, inhibits FASN mRNA, protein expression and enzymatic activity in prostate cancer cells.

CONCLUSIONS

This is the first study to examine the effects of clinically relevant levels of dutasteride on prostate cancer cells at the molecular level and specifically, demonstrating the inhibition of FASN in these cells. Prostate 67: 1111–1120, 2007. © 2007 Wiley‐Liss, Inc.
Feasibility of constructing tissue microarrays from diagnostic prostate biopsies
Authors: Singh Swaroop S. , Mehedint Diana C. , Ford O. Harris , Maygarden Susan J. , Ruiz Bernardo , Mohler James L.
Published: May 2007

OBJECTIVES

The ability to construct prostate tissue microarrays (TMAs) using prostate needle biopsies could allow high throughput molecular profiling to search for prostate cancer prognostic biomarkers.

MATERIALS AND METHODS

Diagnostic prostate biopsies from 13 patients (diagnosed 1996–2000) were obtained from the University of North Carolina (UNC) to construct one prostate TMA under uniform conditions. A second prostate TMA was attempted using diagnostic prostate biopsies from 45 patients (diagnosed 2004) obtained from the North Carolina–Louisiana Prostate Cancer Project (PCaP).

RESULTS

Eleven men had sufficient prostate cancer in their diagnostic prostate biopsy blocks to construct a UNC TMA that yielded six‐micron sections that provided an average of 76% of cores (maximum 99%) to a depth of 360 µm. Diagnostic prostate biopsy blocks from 35 PCaP research subjects were unsuitable for TMA construction as a result of no remaining prostate cancer in 4, insufficient prostate cancer in 9, and insufficient prostate tissue in 22. The PCaP TMA constructed from 10 men yielded an average of 37%, and a maximum of 45%, of cores when sectioned to a depth of 360 µm.

CONCLUSIONS

TMAs may be constructed from diagnostic prostate biopsies obtained at an academic center under uniform conditions. However, excessive facing of blocks and the large number of re‐cuts ordered by many community pathology laboratories deplete diagnostic prostate biopsy tissue. The experience of a population‐based study of men with newly diagnosed prostate cancer in Louisiana and North Carolina suggests that TMAs may not be constructed using diagnostic prostate biopsies from men diagnosed with prostate cancer throughout the United States. Prostate 67: 1011–1018, 2007. © 2007 Wiley‐Liss, Inc.
Secreted frizzled‐related protein 4 inhibits proliferation and metastatic potential in prostate cancer
Authors: Horvath Lisa G. , Lelliott Jayne E. , Kench James G. , Lee C.‐Soon , Williams Elizabeth D. , Saunders Darren N. , Grygiel John J. , Sutherland Robert L. , Henshall Susan M.
Published: May 2007

BACKGROUND

Secreted frizzled‐related proteins (sFRP4) inhibits Wnt signaling and thus cellular proliferation in androgen‐independent prostate cancer cells in vitro. However, increased expression of membranous sFRP4 is associated with a good prognosis in human localized androgen‐dependent prostate cancer, suggesting a role for sFRP4 in early stage disease. Here, we investigated the phenotype of sFRP4 overexpression in an androgen‐dependent prostate cancer model.

METHODS

An sFRP4‐overexpressing androgen‐dependent (LNCaP) prostate cancer model was established to assess changes in cellular proliferation, the expression, and subcellular localization of adhesion molecules and cellular invasiveness, and compared with the findings in sFRP4‐overexpressing androgen‐independent cells (PC3).

RESULTS

sFRP4 overexpression in both cell line models resulted in a morphologic change to a more epithelioid cell type with increased localization of β‐catenin and cadherins (E‐cadherin in LNCaP, N‐cadherin in PC3) to the cell membrane. Functionally, sFRP4 overexpression was associated with a decreased rate of proliferation (P = 0.0005), decreased anchorage‐independent growth (P < 0.001), and decreased invasiveness in PC3 cells (P < 0.0001). Furthermore, increased membranous sFRP4 expression was associated with increased membranous β‐catenin expression (P = 0.02) in a cohort of 224 localized human androgen‐dependent prostate cancers.

CONCLUSIONS

These data suggest that sFRP4 is an inhibitor of prostate cancer growth and invasion in vitro independent of androgen receptor (AR) signaling with correlative evidence in human androgen‐dependent disease suggesting similar changes in the clinical setting. Consequently, potential therapeutic strategies to modulate Wnt signaling by sFRP4 will be relevant to both localized androgen‐dependent prostate cancer and advanced metastatic disease. Prostate 67: 1081–1090, 2007. © 2007 Wiley‐Liss, Inc.