bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and anti‐HIV activity of new 2‐thiolumazine and 2‐thiouracil metal complexes
Authors: Al‐Masoudi Najim A. , Saleh Basil A. , Karim Nesreen Abdul , Issa Ahmed Y. , Pannecouque Christoph
Published: November 2010

A series of new Cu(II), Pt(II), VO(II), Fe(II), and Co(II) complexes (1‐‐5) with 3‐methyl‐6,7‐diphenyllumazine are described. Similarly, complexes from 2‐thiouracil with Cu(II) (6,7) and Pt(II) (8) have been prepared and characterized by spectroscopic methods. All the complexes were assayed for their anti‐HIV‐1 and HIV‐2 activity by examination of their inhibition of HIV‐induced cytopathogenicity in MT‐4 cells. Compound 3 was found to be the most active inhibitor against HIV‐2 in cell culture (EC50 = >18.9 μ g/mL, selectivity index (SI) = 3), which provided a good lead for further optimization. Compounds 6 and 7 exhibited some activity (EC50 = >7.12 μ g/mL and >2.23 μ g/mL) against HIV‐1 and HIV‐2, but no selectivity was observed (SI <1). © 2010 Wiley Periodicals, Inc. Heteroatom Chem 22:44–50, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20654
Polystyrene‐supported aluminum chloride: An efficient and recyclable green catalyst for one‐pot synthesis of 14‐aryl or alkyl‐14H‐dibenzo[a,j]xanthenes
Authors: Rahmatpour Ali , Aalaie Jamal
Published: November 2010

A new, mild, and efficient method has been developed for the one‐pot synthesis of 14‐aryl or alkyl‐14H‐dibenzo[a,j]xanthenes by condensation of 2‐naphthol and aryl or alkyl aldehydes in the presence of a catalytic amount of cross‐linked polystyrene‐supported aluminum chloride (PS/AlCl3) as an ecofriendly heterogeneous catalyst. This polymeric solid acid catalyst is stable and can be easily recovered and reused without appreciable change in its activity. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 22:51–54, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20655
Studies on the toxic effects of microcystin‐LR on the zebrafish (Danio rerio) under different temperatures
Authors: Zhang Xuezhen , Ji Wei , Zhang Huan , Zhang Wei , Xie Ping
Published: November 2010

It is well known that fish have stronger tolerance than mammals to microcystin (MC) exposure, and such a difference is attributed to their different core body temperatures. However, no in vivo study has been conducted to investigate the effects of temperature on MC‐induced toxicity in fish, a typical poikilotherm. Tolerance and detoxification response of zebrafish treated with MC‐LR were investigated under three temperatures. The LD50 values evidently increased with a decline of the temperature (547, 260 and 176 µg kg−1 at 12, 22 and 32 °C, respectively), indicating stronger tolerance of the fish at lower temperatures. Changes in the transcription of glutathione S‐transferase (GST) isoforms in the fish were observed, and their sensitivity of response in the transcription of GST mRNA was on the order of 12 > 32 > 22°C. We screened out several GST genes which were more delicate to solve the MC‐LR exposure at different temperatures, i.e. GST rho1, al, p1 and theta1 in the 12 °C group, and GST zeta1 and p2 in the 22 and 32 °C groups. Our findings partly validate the hypothesis that high temperature enhances toxic effects of MCs on poikilotherms. Our studies also indicate that temperature‐dependent toxic effects should be taken into account for field toxic assessment of microcystins in fish. Copyright © 2010 John Wiley & Sons, Ltd.
An efficient one‐pot synthesis of diarylpyrazolo[1,5‐a]pyrimidine from isoflavones
Authors: Zhang Zun‐Ting , Ma Yu‐Qing , Liang Yong , Xue Dong , He Qing
Published: November 2010

Direct synthetic methods of 6,7‐diphenylpyrazolo[1,5‐a]pyrimidine derivatives have been developed. Cyclocondensation of isoflavones with 3‐aminopyrazole in the presence of sodium methoxide as alkali promoter gave 6,7‐diphenylpyrazolo[1,5‐a]pyrimidines in moderate to good yields. J. Heterocyclic Chem., (2011).
Venture capital approaches to value creation: Contracting and deal structure
Authors: Smith Janet Kiholm
Published: November 2010

This special issue is focused on the viability of venture capital, which depends not only on the ability to address information gaps and incentive issues, but also on the opportunity cost of alternative financing sources and on regulatory and institutional constraints, which vary across countries, industries, and over time.
Public policies and venture capital in supporting SMEs: An economic comparison of available instruments
Authors: Gai Lorenzo , Rossi Federico , Catelani Edoardo
Published: November 2010

In the present economic conditions public bodies are compelled to rethink assistance given to small and medium enterprises in access to credit while venture capital, mutual guarantee provisions and collateral may help these firms to avoid dangerous short‐circuits between demand and offer of financial resources.
Innovation in venture capital backed clean‐technology firms in the UK
Authors: Parris Stuart , Demirel Pelin
Published: November 2010

The venture capital sector may not be supportive of radical new clean‐technology innovation: a potential concern for the UK's vision of achieving a low carbon economy.
Some Remarks on Orlicz‐Lorentz Spaces
Authors: Kamińska Anna
Published: November 2010

Spaces of Lorentz type called Orlicz‐Lorentz spaces are studied. There are given necessary and sufficient conditions for the spaces to be order continuous, separable, KB‐spaces and to contain isometric or isomorphic copy of l∞ or c0. Moreover a criterion for strict convexity of these spaces is found.
On p‐Valently Close‐To‐Convex and Starlike Functions
Authors: Owa Shigeyoshi
Published: November 2010

The object of the present paper is to prove some interesting sufficient conditions for p‐valently close‐to‐convex and starlike functions in the unit disk.
On a Formula for the L2 Wasserstein Metric between Measures on Euclidean and Hilbert Spaces
Authors: Gelbrich Matthias
Published: November 2010

For a separable metric space (X, d) Lp Wasserstein metrics between probability measures μ and v on X are defined by

where the infimum is taken over all probability measures η on X × X with marginal distributions μ and v, respectively. After mentioning some basic properties of these metrics as well as explicit formulae for X = R a formula for the L2 Wasserstein metric with X = Rn will be cited from [5], [9], and [21] and proved for any two probability measures of a family of elliptically contoured distributions.

Finally this result will be generalized for Gaussian measures to the case of a separable Hilbert space.
A Representation of Finitely‐Modular AC‐lattices
Authors: Hamhalter Jan
Published: November 2010

We give a lattice‐theoretic characterization of the lattices of Mackey closed subspaces in a vector space V (dim V ≧ 4): These are exactly complete finitely‐modular AC‐lattices of the length at least four which have mutually perspective atoms.
Double Covers of Some Fano Manifolds as Hyperplane Sections
Authors: Lanteri Antonio , Occhetta Gianluca
Published: November 2010

Let Y be a Fano manifold of dimension n ⩾ 3 with b2(Y and index n – 1 and let A be a projective manifold which is a double cover of Y. We determine which complex projective manifolds can admit A among their hyperplane sections.
On Rate‐Type Viscoplastic Problems with Linear Boundary Conditions
Authors: Rochdi M. , Sofonea M.
Published: November 2010

In this paper we introduce the abstract concept of “linear boundary conditions” in the study of deformable bodies. We establish two existence and uniqueness results concerning respectively quasistatic and dynamic problems involving such type of boundary conditions. We also apply these existence results in the study of viscoplastic problems involving classical boundary conditions.
Variation of Ramification Loci of Generic Projections
Authors: Flenner Hubert , Manaresi Mirella
Published: November 2010

Let X C PN = P be a subvariety of dimension n and ∧ PN be a generic linear subspace of dimension N k ‐ 1 with k ≥ n. Then the linear projection π∧: X → Pk is a finite map. Let R(π∧) be its ramification locus. In this paper we study the map from the Grassmannian G(N ‐ k ‐ 1, N) of planes of dimension N ‐ k ‐ 1 in PN to the Hilbert moduli space given by ∧ R(π∧). We wish to compute in particular the dimension, say, n of the image of this map. The motivation of this question comes from the fact that these ramification cycles are closely related to the Stückrad ‐ Vogel cycle. We show that n is just the transcendence degree of a certain part of this cycle. The main result is that, under some mild hypothesis, in case of a projection X → Pn, i.e., k = n, the map ∧ → R(π∧) is generically finite and so n takes its maximal possible value. Moreover, we show that in the case of smooth surfaces X ∇ P4 and generic projections onto P3 this map is again generically finite if the normal bundle of X in P4 is sufficiently positive.
Nevanlinna Functions, Perturbation Formulas, and Triplets of Hilbert Spaces
Authors: Hassi Seppo , de Snoo Henk
Published: November 2010

Let S be a closed symmetric operator with defect numbers (1,1) in a Hilbert space 𝔥 and let A be a selfadjoint operator extension of S in 𝔥. Then S is necessarily a graph restriction of A and the selfadjoint extensions of S can be considered as graph perturbations of A, cf. [8]. Only when S is not densely defined and, in particular, when S is bounded, 5 is given by a domain restriction of A and the graph perturbations reduce to rank one perturbations in the sense of [23]. This happens precisely when the Q ‐ function of S and A belongs to the subclass No of Nevanlinna functions. In this paper we show that by going beyond the Hilbert space 𝔥 the graph perturbations can be interpreted as compressions of rank one perturbations. We present two points of view: either the Hilbert space 𝔥 is given a one‐dimensional extension, or the use of Hilbert space triplets associated with A is invoked. If the Q ‐ function of S and A belongs to the subclass N1 of Nevanlinna functions, then it is convenient to describe the selfadjoint extensions of S including its generalized Friedrichs extension (see [6]) by interpolating the original triplet, cf. [5]. For the case when A is semibounded, see also [4]. We prove some invariance properties, which imply that such an interpolation is independent of the (nonexceptional) extension.
Towers of Global Function Fields with Asymptotically Many Rational Places and an Improvement on the Gilbert ‐ Varshamov Bound
Authors: Niederreiter Harald , Xing Chaoping
Published: November 2010

We construct infinite class field towers of global function fields with asymptotically many rational places. In this way, we improve on asymptotic bounds of Serre, Perret, Schoof, and Xing. The results can be interpreted equivalently as asymptotic bounds on the number of rational points of smooth algebraic curves over finite fields. As an application, we show an improvement on the Gilbert‐Varshamov bound for linear codes over finite fields of a sufficiently large composite nonsquare order.
Differential Equations on Manifolds with Singularities in Classes of Resurgent Functions
Authors: Schulze B.‐W. , Sternin B. , Shatalov V.
Published: November 2010

In the paper, a new method of constructing asymptotic solutions of differential equations on manifolds with singularities is presented. This method allows not only to widen essentially the space of asymptotics but also to obtain explicit formulas for asymptotic expansions, in particular, in the case when in a neighborhood of a singular point there exist strata of different dimensions.
An Eigenvalue Problem for a Quasilinear Elliptic Equation
Authors: Cheng Yuanji
Published: November 2010

In this paper, we are concerned with the following eigenvalue problem: here Ω is a C1,α‐domain and Δp is the degenerate p‐Laplace operator with p > 1. An interesting special case is when f = π(χ)|u|σ1−1 u+ϕ(χ)|u|σ−1u, 0 < q1 <q2. By using the sub‐ and supersolutions method and the variational method, we prove the existence of the solution of the problem under certain growth conditions for f(χ,u). In the above special case, our results give the existence of at least one positive solution for q2 < p* ‐ 1, where p* is the critical Sobolev exponent, and the existence of at least two positive and two negative solutions for q1 < p ‐ 1 < q2 < p* ‐ 1. We also present a 1D example which has many positive solutions for certain interval of λ and for a special value of λ it has even infinitely many solutions.
Über die Automorphismen einer streng pseudokonvexen CR–Mannigfaltigkeit der Kodimension 2 im ℂ41
Authors: Schmalz G.
Published: November 2010

In der Arbeit wird bewiesen, daß die lokalen isotropen Automorphismen einer streng pseudokonvexen, reell–analytischen, nicht–semiquadratischen CR–Mannigfaltigkeit M der Kodimension 2 im C4 in geeigneten Koordinaten sämtlich linear sind. Dabei können diese Koordinaten so gewählt werden, daß die Gleichung von M Normalform im Sinne von Chern–Moser–Loboda annimmt. Es wird gezeigt, daß die Dimension der Gruppe, die von solchen Automorphismen gebildet wird, höchstens gleich 3 ist. Es werden Beispiele von Mannigfaltigkeiten angegeben, deren Isotropie‐gruppen die möglichen Dimensionen 0,1,2,3 besitzen.
Function Spaces with Exponential Weights II
Authors: Schott Thomas
Published: November 2010

This paper is a continuation of [8]. We study weighted function spaces of type B and F on the Euclidean space Rn, where u is a weight function of at most exponential growth. In particular, u(χ (±|χ|) is an admissible weight. We deal with atomic decompositions of these spaces. Furthermore, we prove that the spaces B and F are isomorphic to the corresponding unweighted spaces B and F.
A Riemann Singularity Theorem for Generalised Brill – Noether Loci
Authors: Teixidor Montserrat
Published: November 2010

Consider a generic vector bundle E of given rank and degree. Consider the subscheme of the Jacobian of line bundles L such that E ⊗ L has a section. We show that the singular locus of this subscheme consists of all line bundles such that E ⊗ L has at least two sections.
The Full T1 Theorem for Certain Triebel ‐ Lizorkin Spaces
Authors: Wang Kunchuan
Published: November 2010

Previous authors have considered generalizations of the David‐Journé T1 theorem to the scale of Triebel ‐ Lizorkin spaces (IRn) under the T1 = 0 and T = 0 assumptions, where T is a (generalized) Calderon ‐ Zygmund operator. We prove boundedness on (IRn) under weaker assumptions on T1 and T1, which are related to the sharp T1, T BMO assumptions for in the David‐Journé theorem. In some cases we also show that our conditions are sharp. By similar techniques, we also obtain sharper conditions for “families of molecules” and “norming families” for these spaces.
On the Injective Tensor Product of Distinguished Frechet Spaces
Authors: Carlos Díaz Juan , Domaeski Pawel
Published: November 2010

An example of two distinguished Fréchet spaces E, F is given (even more, E is quasinormable and F is normable) such that their completed injective tensor product E⊗F is not distinguished. On the other hand, it is proved that for arbitrary reflexive Fréchet space E and arbitrary compact set K the space of E ‐ valued continuous functions C(K, E) is distinguished and its strong dual is naturally isomorphic to ⊗ where L1(μ) = C(K)1.
Local Solutions of Weakly Parabolic Quasilinear Differential Equations
Authors: Dreher Michael , Pluschke Volker
Published: November 2010

We consider a quasilinear parabolic boundary value problem, the elliptic part of which degenerates near the boundary. In order to solve this problem, we approximate it by a system of linear degenerate elliptic boundary value problems by means of semidiscretization with respect to time. We use the theory of degenerate elliptic operators and weighted Sobolev spaces to find a priori estimates for the solutions of the approximating problems. These solutions converge to a local solution, if the step size of the time‐discretization goes to zero. It is worth pointing out that we do not require any growth conditions on the nonlinear coefficients and right‐hand side, since we lire able to prove L∞ ‐ estimates.
Compléments à un Résultat de Safarevic
Authors: Maire Christian
Published: November 2010

Soient k un corps de nombres et p un nombre premier; notons par L la p‐extension maximale de k non‐ramifiée et non‐complexifiée, et par G le groupe de Galois Gal(L/k). On se propose alors de montrer dans la continuité de travaux de Safarevic, lorsque G est fini, l'existence d'un isomorphisme entre H2 (G,FP) et un certain groupe de nombres de k.
Remarks on Quasilinear Hyperbolic Equations with Dynamic Boundary Conditions
Authors: Park Sang Ro
Published: November 2010

In this paper the non‐existence of global solutions of two fourth‐order hyperbolic equations with dynamic boundary conditions is considered. Here we prove stronger results than that of M. Kirane, S. Kouachi and N. Tatar by a different method.
Fréchet Algebra Techniques for Boundary Value Problems on Noncompact Manifolds: Fredholm Criteria and Functional Calculus via Spectral Invariance
Authors: Schrohe Elmar
Published: November 2010

A Boutet de Monvel type calculus is developed for boundary value problems on (possibly) noncompact manifolds. It is based on a class of weighted symbols and Sobolev spaces. If the underlying manifold is compact, one recovers the standard calculus. The following is proven:

The algebra G of Green operators of order and type zero is a spectrally invariant Fréchet subalgebra of L(H), Ha suitable Hilbert space, i. e.,equation image

Focusing on the elements of order and type zero is no restriction since there are order reducing operators within the calculus.

There is a necessary and sufficient criterion for the Fredholm property of boundary value problems, based on the invertibility of symbols modulo lower order symbols, and

There is a holomorphic functional calculus for the elements ofGin several complex variables.
A Class of Index Transforms with General Kernels
Authors: Yakubovich S. B. , Fisher Brian
Published: November 2010

This paper deals with a class of integral transforms of the non ‐ convolution type involving sufficiently general kernels, which depend upon two essentially independent arguments. One of them, in various particular cases, is a parameter or index of the corresponding special functions. This class of integral transforms comprises the famous Kontorovich‐Lebedev and Mehler‐Fock transforms. We study here the mapping properties and give also inversion theorems of the general index transforms on the space Lp(ℝ), p ≥ 1, that covers the respective measurable functions on the whole real axis with the norm

It is shown that the images of the transforms belong to the space Lν, p(ℝ+), νε ℝ, 1 ≤ p ≤ ∞ of functions normed by

In particular, when v = 1/p we get the usual Lp(ℝ+) space. We also direct our attention to the case of the Hilbert space and give certain interesting examples of these transforms.
Norm Closures of Operator Algebras with Symbolic Structure
Authors: Mantlik Frank
Published: November 2010

We investigate norm closures of operator algebras with symbolic structure in an axiomatic setting. Typical examples are given by algebras of zero order pseudodifferential operators on (possibly noncompact) manifolds. It is our aim to study properties of the completed algebras by means of the associated extensions of the symbolic calculus. Particularly we like to prove spectral Invariance or even the ϕ‐property in the sense of B. Gramsch and to discuss some of the main Implications.
A Spectrum Determined by Eigencurves
Authors: Binding Paul , Volkmer Hans
Published: November 2010

This paper investigates the self‐adjoint operator ‐∂2/∂x2 + q(x, y) in the Hilbert space L2((a, b)× (c,d)) subject to the boundary conditions z(a,y) = z(b,y) = 0. It is shown that the spectrum and spectral representation of A are determined by the eigencurves and eigenfunctions of the parameterized regular Sturm‐Liouville operator ‐d2/dx2+ q(x,y).
Spectral Properties of Some Semi ‐ Elliptic Operators in Lp
Authors: Shevchik Vitali
Published: November 2010

Spectral properties of the semi‐elliptic operator
equation image
in Lp (1 < p < ∞) spaces are investigated. In particular it is proved that there exists μ0 such that if μ> μ0, then Aμ, P has the point spectrum and λk(Aμ, P) ˜ where Aμ, P is the unbounded operator generated by Aμ in Lp and λ k (Aμ,P) its eigenvalues.
Formes Quadratiques de Dimension 6
Authors: Laghribi Ahmed
Published: November 2010

Let F be a field of characteristic not equal to 2 and ϕ be an anisotropic quadratic form of dimension 6 and signed discriminant d ≠ 1 such that ϕ F (√d) is anisotropic, Using a generic method, we give a complete characterization of quadratic forms ψ of dimension greater than or equal to 4 such that ϕ becomes isotropic over the function field of the projective quadric defined by the equation ψ = 0 (if dim ψ = 4, we must assume d ±
equation image
{1,d ±ϕ}). This method.also allows us to recover the results of D. W. Hoffmann [9], [10] in dimension 5, 6. This settles the study of isotropy of 6‐dimensional quadratic forms over the function field of a quadric, except for the cases:

1) ϕ F(√ d) is isotropic but not hyperbolic and ψ has dimension 4 but is not similar to a 2‐fold Pfister form.

2) ϕ F(√ d) is anisotropic, dim ψ = 4 and d±ϕ = d±ψ.
Local Spectra and Index of Singular Integral Operators with Piecewise Continuous Coefficients on Composed Curves
Authors: Bishop C. J. , Böttcher A. , Karlovich Yu. I. , Spitkovsky I.
Published: November 2010

We establish a symbol calculus for deciding whether singular integral operators with piecewise continuous coefficients are Fredholm on the Lebesgue space Lp(Γ W) where 1 < p < ∞, Γ is a composed Carleson curve, and W is a Muckenhoupt weight in the class Ap(Γ). We also provide index formulas for the operators in the closed algebra of singular integral operators with piecewise continuous matrix‐valued coefficients. Our main theorem is based upon three pillars: on the identification of the local spectrum of the Cauchy singular integral operator at the endpoints of simple Carleson arcs, on an appropriate “N projections theorem”, and on results of geometric function theory pertaining to the problem of extending Carleson curves and Muckenhoupt weights.
Isotropy of Virtual Albert Forms over Function Fields of Quadrics
Authors: Izhboldin Oleg , Karpenko Nikita
Published: November 2010

Let F be a field of characteristic different from 2 and let ϕ be a virtual Albert form over F, i.e., an anisotropic 6‐dimensional quadratic form over F which is still anisotropic over the field \documentclass{article}\pagestyle{empty}\begin{document}$F\left({\sqrt {d \pm \varphi } } \right).$\end{document} We give a complete description of the quadratic forms Ψ such that ϕ becomes isotropic over the function field F(Ψ). This completes the series of works ([H6], [Lag6], [Lag], [Lee], [M2]) where the question was considered previously.
An Inverse Function Theorem for Fréchet Spaces Satisfying a Smoothing Property and (DN)
Authors: Poppenberg Markus
Published: November 2010

Classical inverse function theorems of Nash‐Moser type are proved for Fréchet spaces that admit smoothing operators as introduced by Nash. In this note an inverse function theorem is proved for Fréchet spaces which only have to satisfy the condition (DN) of Vogt and the smoothing property (SΩ)t; for instance, any Fréchet‐Hilbert space which is an (Ω)‐space in standard form has property (SΩ)t. The main result of this paper generalizes a theorem of Lojasiewicz and Zehnder. It can be applied to the space C∞(K) if the compact K ⊂ ℝN is the closure of its interior and subanalytic; different from classical results the boundary of K may have singularities like cusps. The growth assumptions on the mappings are formulated in terms of the weighted multiseminorms [ ]m,k introduced in this paper; nonlinear smooth partial differential operators on C∞(K) and their derivatives satisfy these formal assumptions.
Toughening of in situ polymerized cyclic butylene terephthalate by addition of tetrahydrofuran
Authors: Abt Tobias , Sánchez‐Soto Miguel , Illescas Silvia , Aurrekoetxea Jon , Sarrionandia Mariasun
Published: November 2010

A new method of toughening polymerized cyclic butylene terephthalate (pCBT) with tetrahydrofuran (THF) is proposed. The pCBT was prepared by in situ ring‐opening polymerization of a commercial cyclic butylene terephthalate, a cyclic form of poly(butylene terephthalate), in the presence of THF. In comparison to conventionally polymerized pCBT, the resultant material was found to be ductile, showing a strain at break of well above 100% in tensile tests. Other matrix properties, such as tensile modulus, tensile strength and glass transition temperature, were not significantly altered by the addition of THF. It was found that the presence of THF enhanced the polymerization reaction, resulting in an increased molecular weight and a narrowed molecular weight distribution. Moreover, remaining oligomers after polymerization were extracted by the THF and a toughened oligomer‐free pCBT was obtained. The influence of time and temperature on the long‐time toughening action of THF was studied. The results showed that samples became brittle after 3 months when subjected to a temperature of 80 °C, resulting in a reduction of the toughening action. Copyright © 2010 Society of Chemical Industry
Sensing the dissociation of a polymeric enzyme by means of an engineered intrinsic probe
Authors: Ainciart N. , Zylberman V. , Craig P.O. , Nygaard D. , Bonomi H.R. , Cauerhff A.A. , Goldbaum F.A.
Published: November 2010

One of the most remarkable characteristics of Brucella lumazine synthase (BLS) is its versatility to undergo reversible dissociation and reassociation as a polymeric scaffold. We have proposed a mechanism of dissociation and unfolding of BLS. Using static light scattering (SLS) analysis, we were able to demonstrate that the decameric assembly dissociates into two different conditions [pH 5 or 2M guanidinium chloride (GdnHCl) pH 7] forming stable folded pentamers. The transition from folded pentamers to unfolded monomers by GdnHCl denaturation is highly cooperative and can be measured by different spectroscopic techniques. In this work, we show the successful insertion of an intrinsic probe to study in more detail the equilibria described in previous publications. For that purpose, we performed single‐point mutations of Phe residues 121 and 127, located at the pentamer–pentamer and monomer–monomer interface, respectively, to Trp residues. These mutations produced only a marginal perturbation of the BLS structure. We analyzed the unfolding and stability of the mutants through different techniques: far‐and near‐UV CD, SLS, dynamic light scattering, and fluorescence spectroscopy. The introduced intrinsic probe could be used to gain insights into the detailed folding and assembly mechanism of this protein. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Protein rigidity and thermophilic adaptation
Authors: Radestock Sebastian , Gohlke Holger
Published: November 2010

We probe the hypothesis of corresponding states, according to which homologues from mesophilic and thermophilic organisms are in corresponding states of similar rigidity and flexibility at their respective optimal temperatures. For this, the local distribution of flexible and rigid regions in 19 pairs of homologous proteins from meso‐ and thermophilic organisms is analyzed and related to activity characteristics of the enzymes by constraint network analysis (CNA). Two pairs of enzymes are considered in more detail: 3‐isopropylmalate dehydrogenase and thermolysin‐like protease. By comparing microscopic stability features of homologues with the help of stability maps, introduced for the first time, we show that adaptive mutations in enzymes from thermophilic organisms maintain the balance between overall rigidity, important for thermostability, and local flexibility, important for activity, at the appropriate working temperature. Thermophilic adaptation in general leads to an increase of structural rigidity but conserves the distribution of functionally important flexible regions between homologues. This finding provides direct evidence for the hypothesis of corresponding states. CNA thereby implicitly captures and unifies many different mechanisms that contribute to increased thermostability and to activity at high temperatures. This allows to qualitatively relate changes in the flexibility of active site regions, induced either by a temperature change or by the introduction of mutations, to experimentally observed losses of the enzyme function. As for applications, the results demonstrate that exploiting the principle of corresponding states not only allows for successful thermostability optimization but also for guiding experiments in order to improve enzyme activity in protein engineering. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Effect of flanking residues on the conformational sampling of the internal fusion peptide from Ebola virus
Authors: Jaskierny Adam J. , Panahi Afra , Feig Michael
Published: November 2010

Fusion peptides mediate viral and host‐cell membrane fusion during viral entry. The monomeric form of the internal fusion peptide from Ebola virus was studied in membrane bilayer and water environments with computer simulations using replica exchange sampling and an implicit solvent description of the environment. Wild‐type Ebola fusion peptide (EFP), the W8A mutant form, and an extended construct with flanking residues were examined. It was found that the monomeric form of wild‐type EFP adopts coil–helix–coil structure with a short helix from residues 8 to 11 mostly sampling orientations parallel to the membrane surface. W8A mutation disrupts the helicity in the N‐terminal region of the peptide and leads to a preference for slightly oblique orientation relative to the membrane surface. The addition of flanking residues also alters the fusion peptide conformation with either a helix–break–helix structure or extended N and C‐termini and reduced membrane insertion. In water, the fusion peptide is found to adopt structures with low helicity. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Reduced metribuzin pollution with phosphatidylcholine–clay formulations
Authors: Undabeytia Tomás , Recio Esther , Maqueda Celia , Morillo Esmeralda , Gómez‐Pantoja Eulalia , Sánchez‐Verdejo Trinidad
Published: November 2010

BACKGROUND: Metribuzin is a widely used herbicide that has been identified as a groundwater contaminant. In this study, slow‐release formulations of metribuzin were designed by encapsulating the active ingredient in phosphatidylcholine (PC) vesicles and adsorbing the vesicles onto montmorillonite.

RESULTS: The maximum active ingredient content in the slow‐release formulations was 246 g kg−1. Infrared spectroscopy results revealed that the hydrophobic interactions between metribuzin and the alkyl chains on PC were necessary for encapsulation. In addition, water bridges connecting the herbicide and the PC headgroup enhanced the solubility of metribuzin in PC. Adsorption experiments in soils were performed to evaluate the relationship between sorption and leaching. Funnel experiments in a sandy soil revealed that the herbicide was not irreversibly retained in the formulation matrix. In soil column experiments, PC–clay formulations enhanced herbicide accumulation and biological activity in the top soil layer relative to a commercial formulation. PC–clay formulations also reduced the dissipation of metribuzin by a factor of 1.6–2.5.

CONCLUSIONS: A reduction in the recommended dose of metribuzin can be achieved by employing PC–clay formulations, which reduces the environmental risk associated with herbicide applications. Moreover, PC and montmorillonite are non‐toxic and do not negatively affect the environment. Copyright © 2010 Society of Chemical Industry
The semi‐geostrophic diagnosis of vertical motion. I: Formulation and coordinate transformations
Authors: Pedder Mike A. , Thorpe Alan J.
Published: November 2010

Theoretical considerations suggest that the semi‐geostrophic (SG) omega equation should provide a more accurate diagnosis of vertical velocity than the classical quasi‐geostrophic (QG) omega equation in the presence of significant horizontal variations in static stability and potential vorticity. Only very few previous studies have compared the performance of the two methods applied to either real or simulated data. Furthermore, it is almost certain that such comparisons have been affected by uncertainties associated with transformations between physical and geostrophic momentum (GM) coordinates, these being necessary in order to solve the SG omega equation in a form which retains the conceptual simplicity of the QG omega equation. Here we describe an accurate method of mapping between physical and GM coordinates which is suitable for operating on a large, discrete data base. The result of an inverse mapping is used to measure the accuracy of the method. This is shown to be sensitive to the chosen grid‐point resolution in GM space, which may need to be considerably greater than the given resolution in physical space in order to resolve dynamically significant features in regions of negative geostrophic shear.

The SG equations do not apply when the Jacobian of the GM coordinate transformation (J) changes sign within the domain of the analysis. If such a situation occurs with real data then it is necessary to apply an adjustment to the sampled geopotential (or pressure) data, in order to satisfy the condition J > 0 everywhere prior to a SG diagnosis of vertical velocity. A variational approach to this problem is described and tested using data generated by a primitive‐equation model of a developing cyclone.
Can a relaxation technique be used to validate clouds and sulphur species in a GCM?
Authors: Feichter Johann , Lohmann Ulrike
Published: November 2010

The Hamburg version of the European Centre for Medium‐Range Weather Forecasting (ECMWF) general circulation model, ECHAM4, developed for climate studies, is used to study the hydrological cycle and the atmospheric sulphur cycle. A technique, the Newtonian relaxation, is introduced to compare results from the model with measurements of cloud parameters and sulphur species concentrations. The model is forced by ECMWF analyses to simulate September 1993, and results are compared to observations on different spatial and temporal scales: monthly mean horizontal satellite data, daily mean averages at European and Canadian stations and aircraft soundings over the north Atlantic off the Canadian coast. The model is able to reproduce monthly mean horizontal distributions of liquid water path and precipitation. Daily mean precipitation fluxes and the temporal evolution of gaseous and particulate sulphur also agree quite well with observations. Based on this comparison with observations the performance of two different cloud physics parametrizations is discussed. These experiments indicate that variables like relative humidity, cloud cover and precipitation are controlled by the large‐scale dynamics, whereas the cloud water content depends on the parametrization of the cloud microphysics. Coupling of the model‐calculated sulphate mixing ratios to the cloud microphysics improves the model's sulphate distribution but slightly worsens the agreement between calculated and observed precipitation.
Turbulence on the lee side of a mountain range: Aircraft observations during PYREX
Authors: Attié J.‐L. , Druilhet A. , Bénech B. , Durand P.
Published: November 2010

This study presents an analysis of turbulence data from aircraft measurements made during the PYREX experiment. The data were gathered in a central region of the Pyrénées, a mountain‐range with a more or less west‐east orientation which constitutes a major barrier for northerly and southerly flows. The data used come principally from a Merlin IV aircraft which performed about 100 straight‐and‐level 20 km runs perpendicular or parallel to the main mountain‐range axis. The basic turbulence moments are presented. The data from mountain flows with similar upstream conditions were gathered together in order to construct composite two‐dimensional turbulence fields in the vertical plane perpendicular to the axis of the range. These fields clearly show the location of the turbulence areas on the lee side of the mountain range. The turbulent kinetic energy field shows that turbulence is principally produced by a wake effect. On the lee side the profiles of the various turbulence parameters indicate a maximum at an altitude close to the average height of the mountain in a region having both a strong wind shear and a weak lapse rate. Finally, we show that the turbulence observed in this study obeys the universal law σ‐3ωϵλ≈︁ constant, where s̀w is the standard deviation of the vertical velocity, λ the spectral length‐scale and ϵ the dissipation rate of turbulent kinetic energy. The average value of 2.3 found for this constant is comparable to the values found by other authors under various conditions of turbulence, in particular homogeneous turbulence.
Tandem queues for inventory management under random perturbations
Authors: Sobieczky Florian , Rappitsch Gerhard , Stadlober Ernst
Published: November 2010

Using the theory of M/M/1 queues at stationarity, we provide criteria of stability (recurrence) for a stochastic inventory model with an observed selling rate and an optimally chosen buying rate. Optimality is based on the maximum gain under stability, where buying and selling prices, as well as shop‐ and stock‐keeping costs are incorporated into the model. An important aspect is to achieve robustness of the stocking process by minimizing the fluctuation of the predicted gain. This robustness can be achieved by controlling intermediate transfer rates of the assumed stochastic tandem network. Stochastic simulations demonstrate the applicability of the stability criteria under several scenarios of differing intensities of perturbation. Copyright © 2010 John Wiley & Sons, Ltd.
Bayesian calculation of optimal burn‐in time using the joint criteria of cost and delivered reliability
Authors: Ulusoy, Selda Kapan , Mazzuchi Thomas A. , Perlstein Dror
Published: November 2010

Burn‐in is a quality control process used to minimize the warranty cost of a product by screening out defective products through prior operation for a period of time before sale. Two decision criteria used to determine the optimal burn‐in time are the maximization of the reliability of the delivered product and the minimization of the total cost, which are composed of the cost of burn‐in process and the cost of warranty claims. Because of uncertainty regarding the underlying lifetime distribution of the product, both the product reliability and the total cost are random variables. In this paper, the uncertainty in reliability and cost is quantified by use of Bayesian analysis. The joint distribution of reliability and cost is inferred from the uncertainty distribution of the parameters of the product lifetime distribution. To incorporate the uncertainty in reliability and cost as well as the tradeoff between them into the selection of optimal burn‐in time, the joint utility function of reliability and cost is constructed using the joint distribution of reliability and cost. The optimal burn‐in time is selected as the time that maximizes the joint utility function. Copyright © 2010 John Wiley & Sons, Ltd.
Identifying elements critical for functional and sustainable professional learning communities
Authors: Richmond Gail , Manokore Viola
Published: November 2010

In this paper, we examined data collected as part of a 5‐year project designed to foster reform‐based urban science teaching through teachers' communities of inquiry. Drawing upon a distributed leadership framework, we analyzed teacher “talk” during professional learning community (PLC) meetings. This analysis yielded five elements: teacher learning and collaboration, community formation, confidence in knowledge of content and guided inquiry, concerns about the impact of accountability measures on teaching and learning, and sustainability of reform. Follow‐up interviews with participants reinforced the importance of these elements. While accountability measures were found to have a significant impact on science teaching, participants were also able to use their PLC‐based experiences to develop strategies to deal with such external constraints. Facilitation and leadership also play key roles in establishing and maintaining PLCs in this urban setting. Finally, we present a revised framework that incorporates the elements we identified to describe those local and systemic factors critical for successful implementation and influence of professional development efforts. © 2010 Wiley Periodicals, Inc. Sci Ed 95: 543–570, 2011
Who wants to have a career in science or math? exploring adolescents' future aspirations by gender and race/ethnicity
Authors: Riegle‐Crumb Catherine , Moore Chelsea , Ramos‐Wada Aida
Published: November 2010

Our study utilizes data from a national cohort of eighth‐grade students to consider how different gender and racial/ethnic subgroups compare to White males in their likelihood to aspire toward a science or math occupation and examine the roles that self‐concept, enjoyment, and achievement may play in shaping disparities at this early point in occupational trajectories. We find that the importance of enjoyment, self‐concept, and achievement in explaining disparities in science career aspirations relative to White males varies according to the female subgroup considered, such that no singular story applies to females across different racial/ethnic backgrounds. For math, White and Hispanic females remain approximately half as likely as White males to aspire to a math occupation regardless of all indicators we consider. Finally, Black and Hispanic adolescent boys have generally comparable aspirations toward future careers in science and math as their White male peers, despite notably large differences in achievement. We discuss implications of our results for future research on equity. © 2010 Wiley Periodicals, Inc. Sci Ed 95: 458–476, 2011
New nonlinear anti‐seismic steel device for the increasing the seismic capacity of multi‐storey reinforced concrete frames
Authors: Papadopoulos Panikos
Published: November 2010

In order to increase the seismic capacity of multi‐storey planar reinforced concrete (r/c) frames, a new metal frictional device, which the capacity of a restricted rotation around the horizontal axis perpendicular to the vertical frame plane, is presented. The proposed steel device is joined to the four joints of the vertical floor span of the frame via four diagonal steel dual‐hinge bars. During the above restricted rotation, frictional forces develop, due to a suitable synthetic material that is inserted into the rotational frictional connections. When the horizontal relative floor displacement, between two floors, exceeds a desired specific value, then the proposed device locks and the diagonal steel bar becomes fully activated to tension, adding significant additional strength to the frame. This device is installed in a vertical floor span, but it is worth noting that the devices can be placed at floor spans that are not on the same vertical line. The nonlinear numerical (static/dynamic) analyses carried out in the present article, shows that the proposed devices contribute in increase of the lateral stiffness of the frame, the lateral strength of the frame in the inelastic area and the absorption of the inserted seismic energy. Furthermore, this device protects the diagonal steel bars from the buckling or from premature failure of compression. In addition, the proposed device is designed in a way that allows it to operate effectively under large horizontal relative floor displacements due to the cyclic dynamic loads, and can be used instead of the structural r/c walls. Copyright © 2010 John Wiley & Sons, Ltd.
A New 3D Supramolecular Manganese(II) Complex Constructed from Benzimidazole‐5,6‐dicarboxylate and Oxalate: Synthesis, Structural, and Magnetic Properties
Authors: Geng Jin‐Peng , Wang Zhao‐Xi , Wu Qiong‐Fang , Li Ming‐Xing , Xiao Hong‐Ping
Published: November 2010

A new manganese(II) complex [Mn3(bidc)2(C2O4)(H2O)10]n (1) (bidc = benzimidazole‐5,6‐dicarboxylate) was synthesized and characterized by X‐ray crystallography. X‐ray diffraction shows that complex 1 has a neutral, one‐dimensional (1D) brick wall chain structure. With the intramolecular and intermolecular hydrogen bonding interactions, the adjacent chains are joined into a 3D suparmolecular architecture. IR spectroscopy and variable temperature magnetic susceptibility measurements were made, which indicated weak antiferromagnetic coupling between the MnII ions in complex 1.
On the Reactivity of the Platina‐β‐diketone [Pt2{(COMe)2H}2(μ‐Cl)2] Towards Ph2PCH2CH2CH2SOxPh (x = 0, 2)
Authors: Block Michael , Bette Martin , Wagner Christoph , Steinborn Dirk
Published: November 2010

The reaction of the electronically unsaturated platina‐β‐diketone [Pt2{(COMe)2H}2(μ‐Cl)2] (1) with Ph2PCH2CH2CH2SPh (2) leads selectively to the formation of the acetyl(chlorido) platinum(II) complex (SP‐4‐3)‐[Pt(COMe)Cl(Ph2PCH2CH2CH2SPh‐κP,κS)] (4) having the γ‐phosphinofunctionalized propyl phenyl sulfide coordinated in a bidentate fashion (κP,κS). In boiling benzene complex 4 undergoes decarbonylation yielding the methyl(chlorido) platinum(II) complex (SP‐4‐3)‐[PtMeCl(Ph2PCH2CH2CH2SPh‐κP,κS)] (6). However, the reaction of 1 with the analogous γ‐diphenylphosphinofunctionalized propyl phenyl sulfone Ph2PCH2CH2CH2SO2Ph (3) affords the acetyl(chlorido) platinum(II) complex (SP‐4‐4)‐[Pt(COMe)Cl(Ph2PCH2CH2CH2SO2Ph‐κP)2] (5). In boiling benzene complex 5 undergoes a CO extrusion yielding (SP‐4‐4)‐[PtMeCl(Ph2PCH2CH2CH2SO2Ph‐κP)2] (8) whereas in presence of 1 the formation of the carbonyl complex (SP‐4‐3)‐[PtMeCl(CO)(Ph2PCH2CH2CH2SO2Ph‐κP)] (7) is observed. Addition of Ag[BF4] to complex 5 leads to the formation of the cationic methyl(carbonyl) platinum(II) complex (SP‐4‐1)‐[PtMe(CO)(Ph2PCH2CH2CH2SO2Ph‐κP)2][BF4] (9). All complexes were characterized by microanalysis and NMR spectroscopy (1H, 13C, 31P) and complexes 4 and 6 additionally by single‐crystal X‐ray diffraction analyses.
A pictorial review of benign hepatocellular nodular lesions: comprehensive radiological assessment incorporating the concept of anomalous portal tract syndrome
Authors: Ueda Takuya , Starkey Jay , Mori Kensaku , Fukunaga Kiyoshi , Shimofusa Ryota , Motoori Ken , Minami Manabu , Kondo Fukuo
Published: November 2010

Background/purpose

Although the pathological categorization system advocated by the International Working Party (IWP) on Terminology has been helpful in categorizing benign hepatocellular lesions, the diverse clinicopathological features of the lesions still cause confusion of diagnosis in clinical settings. Recently, an integrated disease concept termed “anomalous portal tract syndrome” (APTS) has been proposed as a congenital anomaly of the portal tract, being a single unifying etiological factor underlying the disorder. In this article, we discuss the radiological features of benign nodular hepatocellular lesions incorporated in the concept of APTS.

Methods

We systematically reviewed the literature on benign hepatocellular lesions based on the concept of APTS, as well as standard IWP terminology. For this pictorial review, we selected six representative cases and assessed the radiological features of the cases based on the concept of APTS.

Results

The comprehensive assessment based on APTS enabled the systematic categorization of benign hepatocellular lesions, including nodular regenerative hyperplasia, large regenerative nodules, partial nodular transformation, focal nodular hyperplasia, and hepatocellular adenoma, and was helpful in understanding the overlapping features of these lesions.

Conclusions

Although the disease concept of APTS is still evolving, it is nonetheless helpful in comprehensively understanding the clinicopathological and radiological features of various benign hepatocellular lesions.