bluuebunny/crossref_metadata_2025 huggingface dataset:
The non-autonomous wave equation with general Wentzell boundary conditions
Authors: Favini Angelo , Gal Ciprian G. , Goldstein Gisèle Ruiz , Goldstein Jerome A. , Romanelli Silvia
Published: July 2007

We study the problem of the well-posedness for the abstract Cauchy problem associated to the non-autonomous one-dimensional wave equation utt = A(t)u with general Wentzell boundary conditions

Here A(t)u := (a(x, t)ux)x, a(x, t) ≥ ε > 0 in [0, 1] × [0, + ∞) and βj(t) > 0, γj(t) ≥ 0, (γ0(t), γ1(t)) ≠ (0,0). Under suitable regularity conditions on a, βj, γj we prove the well-posedness in a suitable (energy) Hilbert space
Superconductors surrounded by normal materials
Authors: Giorgi Tiziana
Published: July 2007

We consider a generalized Ginzburg–Landau energy functional modelling a superconductor surrounded by a material in the normal state. In this model, the order parameter is defined in the whole space. We derive existence of a global minimizer in weighted Sobolev spaces for both square-integrable and constant-applied magnetic fields. We then prove boundedness and classical elliptic estimates for the order parameter, in order to study the loss of superconductivity for high applied magnetic fields. In two dimensions for the general case and in three dimensions for the case of constant permeability, we show the existence of an upper critical field above which the only finite-energy weak solutions are the normal states. For the three-dimensional case, we show that as the applied field tends to infinity, finite-energy weak solutions tend to the normal state
Phragmén–Lindelöf theorems in cylinders
Authors: Almeeh Hasan , Lancaster Kirk
Published: July 2007

In unbounded cylindrical domains, new Phragmén–Lindelöf theorems ‘at infinity’ are established for solutions of Dirichlet problems for elliptic equations whose operators belong to a large class to which the existing literature does not apply.
Temporal and spatial decays for the Navier–Stokes equations
Authors: Bae Hyeong-Ohk , Jin Bum Ja
Published: July 2007

We obtain spatial and temporal decay rates of weak solutions of the Navier–Stokes equations, and for strong solutions. For the spatial decay rate of the weak solutions, the power of the weight given by He and Xin in 2001 does not exceed 3/2;. However, we show the power can be extended up to 5/2;.
Left semi-perfect abundant semi-groups of type W
Authors: Guo Xiaojiang , Shum K. P.
Published: July 2007

We call a quasi-adequate semi-group whose set of idempotents forms a left [right] quasi-normal band a left [right] semi-perfect abundant semi-group. After obtaining some characterization theorems of such quasi-adequate semi-groups, we establish a structure for left [right] semi-perfect abundant semi-groups of type W. Our results generalize and strengthen the results of El-Qallali and Fountain on quasi-adequate semi-groups.
Exponential attractors and finite-dimensional reduction for non-autonomous dynamical systems
Authors: Efendiev M. , Zelik S. , Miranville A.
Published: July 2007

We suggest in this paper a new explicit algorithm allowing us to construct exponential attractors which are uniformly Hölder continuous with respect to the variation of the dynamical system in some natural large class. Moreover, we extend this construction to non-autonomous dynamical systems (dynamical processes) treating in that case the exponential attractor as a uniformly exponentially attracting, finite-dimensional and time-dependent set in the phase space. In particular, this result shows that, for a wide class of non-autonomous equations of mathematical physics, the limit dynamics remains finite dimensional no matter how complicated the dependence of the external forces on time is. We illustrate the main results of this paper on the model example of a non-autonomous reaction–diffusion system in a bounded domain.
Multi-clustered high-energy solutions for a phase transition problem
Authors: Felmer Patricio L. , Martínez Salomé , Tanaka Kazunaga
Published: July 2007

We study the balanced Allen–Cahn problem in a singular perturbation setting. We are interested in the behaviour of clusters of layers, i.e. a family of solutions uε(x) with an increasing number of layers as ε → 0. In particular, we give a characterization of cluster of layers with asymptotically positive length by means of a limit energy function and, conversely, for a given admissible pattern, i.e. for a given a limit energy function, we construct a family of solutions with the corresponding behaviour.
Stabilization to a singular steady state for the Frank-Kamenetskii equation in a critical dimension
Authors: Galaktionov Victor A. , King John R.
Published: July 2007

We study the phenomenon of the infinite-time stabilization of classical global solutions of nonlinear reaction–diffusion equations to an unbounded (singular) stationary state and we present a new case of such an asymptotic singularity pattern formation. We concentrate on the most famous parabolic model, namely the semi-linear Frank-Kamenetskii equation from combustion theory,

where B is a ball in RN. Our goal is to show that a new asymptotic problem arises precisely in dimension 10, not being available in other dimensions (which were studied earlier). For N = 10, we fix the ball B = {|x| < 4} and take bounded initial data u0 below the singular stationary solution Us(x) = ln(16/|x|2), which is unbounded at the origin x = 0.

We establish a sharp estimate on the rate of convergence u(x, t) → Us(x) as t → ∞ on compact subsets bounded away from x = 0 and also at the singularity point. We show that u(0, t) = α0t + O(ln t) → ∞, where the positive constant α0 is given by the first eigenvalue of the associated linear differential operator. We present formal asymptotic results showing that a detailed asymptotic analysis depends on a quite involved balance between various linear and nonlinear terms. Moreover, similar critical asymptotic behaviour is shown to exist in various related nonlinear second- and higher-order parabolic equation.
Global attraction for systems with almost C1 vector fields
Authors: Hou Zhanyuan
Published: July 2007

Sufficient conditions are given for an autonomous differential system

to have a single point global attractor (repeller) with f continuously differentiable almost everywhere. These results incorporate those of Hartman and Olech as a special case even when the condition f ∈ C1(D, RN) is fully met. Moreover, these criteria are simplified for a class of region-wise linear systems in RN.
Weights for commutators of the one-sided discrete square function, the Weyl fractional integral and other one-sided operators
Authors: Lorente M. , Riveros M. S.
Published: July 2007

The purpose of this paper is to prove strong-type inequalities with one-sided weights for commutators (with symbol b ∈ BMO) of several one-sided operators, such as the one-sided discrete square function, the one-sided fractional operators, or one-sided maximal operators given by the convolution with a smooth function. We also prove that b ∈ BMO is a necessary condition for the boundedness of commutators of these one-sided operators.
Infinitesimal elastic–plastic Cosserat micropolar theory. Modelling and global existence in the rate-independent case
Authors: Neff Patrizio , Chełmiński Krzysztof
Published: July 2007

In this article we investigate the regularizing properties of generalized continua of Cosserat micropolar type in the elasto-plastic case. We propose an extension of classical infinitesimal elasto-plasticity to include consistently non-dissipative micropolar effects. It is shown that the new model is thermodynamically admissible and allows for a unique, global-in-time solution of the corresponding rate-independent initial–boundary-value problem. The method of choice is the Yosida approximation and a passage to the limit.
Conicting nonlinearities and spectral lacunae bounded on one side by eigenvalues
Authors: Ruppen Hans-Jörg
Published: July 2007

This paper deals with eigenvalue problems of the form

where 0 < σ < τ and V(x) is such that the spectrum of −u″ consists of eigenvalues λ1, λ2,…situated below the continuous spectrum [Λ,+∞[.

We analyse the existence of (multiple) solutions for λ < λ1 as well as for λ > λ1 when λ is in a spectral lacuna.

The existence of solutions depends on the weight of μ > 0. Moreover, when λ increases (while μ is kept fixed), some solutions are lost when crossing eigenvalues.

The above results are derived with the help of an abstract approach based on variational techniques for multiple solutions. This approach can even be applied to a wider class of problems, the one presented herein being only a model problem.
Weighted inequalities for Cesàro maximal operators in Orlicz spaces
Authors: Salvador Pedro Ortega , Torreblanca Consuelo Ramírez
Published: July 2007

Let 0 < α ≤ 1 and let M+α be the Cesàro maximal operator of order α defined by

In this work we characterize the pairs of measurable, positive and locally integrable functions (u, v) for which there exists a constant C > 0 such that the inequality

holds for all λ > 0 and every f in the Orlicz space LΦ(v).
We also characterize the measurable, positive and locally integrable functions w such that the integral inequality

holds for every f ∈ LΦ(w).
The discrete versions of this results allow us, by techniques of transference, to prove weighted inequalities for the Cesàro maximal ergodic operator

associated with an invertible measurable transformation, T, which preserves the measure.

Finally, we give sufficient conditions on w for the convergence of the sequence of Cesàro-α ergodic averages for all functions in the weighted Orlicz space LΦ(w).
Homogenization of a class of nonlinear eigenvalue problems
Authors: Baffico L. , Conca C. , Rajesh M.
Published: July 2007

In this article we study the asymptotic behaviour of the eigenvalues of a family of nonlinear monotone elliptic operators of the form Aε = −div(aε (x, ∇u)), which are sub-differentials of even, positively homogeneous convex functionals, under the assumption that the operators G-converge to an operator Ahom = −div(ahom(x, ∇u)). We show that any limit point λ of a sequence of eigenvalues λε is an eigenvalue of the limit operator Ahom, where λε is an eigenvalue corresponding to the operator Aε. We also show the convergence of the sequence of first eigenvalues to the corresponding first eigenvalue of the homogenized operator.
An asymptotic formula for the voltage potential in a perturbed ε-periodic composite medium containing misplaced inclusions of size ε
Authors: Ben Hassen M. F. , Bonnetier E.
Published: July 2007

We consider composite media made of homogeneous inclusions with C1,α,boundaries. Our goal is to compare the potential uε in a perfectly periodic composite with the potential uε,d, of a perturbed periodic medium, where the periodicity defects consist of misplaced inclusions. We give an asymptotic expansion of the difference uε,d − uε away from the defects and show that, to first order, a misplaced inclusion manifests itself via a polarization tensor, which is characterized.
Asymptotic behaviour of positive steady states to a predator—prey model
Authors: Du Yihong , Wang Mingxin
Published: July 2007

To understand the heterogeneous spatial effect on predator–prey models, we study the behaviour of the positive steady states of a predator–prey model as certain parameters are small or large. We compare the case when the model has a spatial degeneracy with the case when it does not have such a degeneracy. Our results show that the effect of the degeneracy can be clearly observed in one limiting case, but not in the others.
Symmetry of solutions to optimization problems related to partial differential equations
Authors: Cuccu Fabrizio , Porru Giovanni
Published: July 2007

We investigate maxima and minima of some functionals associated with solutions to Dirichlet problems for elliptic equations. We prove existence results and, under suitable restrictions on the data, we show that any maximal configuration satisfies a special system of two equations. Next, we use the moving-plane method to find symmetry results for solutions of a system. We apply these results in our discussion of symmetry for the maximal configurations of the previous problem.
Existence of minimizers for a finite-strain micromorphic elastic solid
Authors: Neff Patrizio
Published: July 2007

We investigate geometrically exact generalized continua of micromorphic type in the sense of Eringen. The two-field problem for the macrodeformation φ and the affine microdeformation P̄ ∈ GL+(3, R) in the quasistatic, conservative load case is investigated in a variational form. Depending on material constants, two existence theorems in Sobolev spaces are given for the resulting nonlinear boundary-value problems. These results comprise existence results for the micro-incompressible case P̄ ∈ SL(3, R) and the Cosserat micropolar case P̄ ∈ SO(3, R). In order to treat external loads, a new condition, called bounded external work, has to be included, which overcomes the conditional coercivity of the formulation. The possible lack of coercivity is related to fracture of the micromorphic solid. The mathematical analysis uses an extended Korn first inequality. The methods of choice are the direct methods of the calculus of variations.
Nonlinear elliptic equations with critical potential and critical parameter
Authors: Shen Yao Tian , Yao Yang Xin
Published: July 2007

We give a positive answer to an open problem about Hardy's inequality raised by Brézis and Vázquez, and another result obtained improves that of Vázquez and Zuazua. Furthermore, by this improved inequality and the critical-point theory, in a k-order Sobolev–Hardy space, we obtain the existence of multi-solution to a nonlinear elliptic equation with critical potential and critical parameter.
Uniqueness of the exact solutions of the Navier—Stokes equations having null nonlinearity
Authors: Kim Sun-Chul , Okamoto Hisashi
Published: July 2007

We consider an overdetermined system of elliptic partial differential equations arising in the Navier–Stokes equations. This analysis enables us to prove that the well-known classical solutions such as Couette flows and others are the only solutions that satisfy both the stationary Navier–Stokes and Euler equations.
Phosphorylation pattern of the p90rskand mitogen-activated protein kinase (MAPK) molecule: comparison ofin vitroandin vivomatured porcine oocytes
Authors: Schuon C. , Ebeling S. , Meinecke B.
Published: July 2007

The overall objective was to elucidate the phosphorylation pattern and activity of the kinase p90rsk, a substrate of mitogen-activated protein kinase (MAPK), duringin vitroandin vivomaturation of pig oocytes. Cumulus–oocyte complexes were collected from slaughtered pigs and maturedin vitro(0, 22, 26, 30, 34, 46 h) with and without the MEK inhibitor U0126. Forin vivomaturation, gilts were stimulated with equine chorionic gonadotrophin (eCG) (600–800 IU). Maturation was induced 72 h later with hCG (500 IU). Oocytes were obtained surgically (0, 22, 30 h). The samples were submitted to electrophoresis and protein blotting analysis. Enhanced chemiluminescence was used for visualization.In vitromatured oocytes were further submitted to a commercially available radioactive kinase assay to determine kinase activity. It was shown that oocytes, as well as cumulus cells, already possess a partially phosphorylated p90rskat the time of removal from follicles, with a further phosphorylation of the molecule occurring between 22–24 h after the initiation of culture, andin vivomaturation. The phosphorylation of p90rskcoincides with the phosphorylation of MAPK and can be prevented by U0126, indicating a MAPK-dependent phosphorylation of p90rsk. Phosphorylation of thein vivomatured oocytes occurred shown as a band of less than 200 kDa. This is presumably a molecule complex, with MAPK not being a component. Therefore, the p90rskmoleculein vivoexists as a dimer. Determination of kinase activity demonstrated decreasing enzyme activities. This led to the conclusion that the assay is not specific for p90rsk, instead measuring p70S6kinase activities.
“THE INTERCOURSE BETWEEN THE SQUIRE AND HIS SON”: THE FATHER-SON MARRIAGE PLOT AND THE CREATION OF THE ENGLISH GENTLEMAN IN ANTHONY TROLLOPE'SDOCTOR THORNE
Authors: Gurfinkel Helena
Published: July 2007

“HE IS (NOT) A GENTLEMAN” is a verdict that we frequently encounter in Trollope's novels. The writer's concern with defining the English gentleman is virtually obsessive; however, his effort is fraught with numerous frustrating contradictions, reflecting the Victorians’ struggle to decide what constitutes exemplary masculinity. In some instances, Trollope's gentleman is a product of a certain class, while in others such elusive and intangible criteria as physical appearance and moral conduct come to define him. Despite the perennial identification of the name “Trollope” and Trollope's writing with thoroughly conventional ways of constructing gender, I argue that his gentleman is an expression of his nostalgia for an ideal of manhood that possesses traditionally feminine characteristics.
NURSERY POETICS: AN EXAMINATION OF LYRIC REPRESENTATIONS OF THE CHILD IN TENNYSON'S “THE PRINCESS”
Authors: Barton Anna Jane
Published: July 2007

“THE PRINCESS,”TENNYSON's narrative poem about a radically feminist princess and a cross-dressing prince, framed by an imagined argument between Victorian men and women concerning the role of women in modern society, has, understandably, formed the central text in a number of articles about nineteenth-century gender poetics. Critics have been eager to engage with the fictional authors of the narrative, casting Tennyson as, on the one hand, a bastion of Victorian patriarchy, and on the other a subversive feminist. Donald E. Hall, in an essay, published in his collectionFixing Patriarchy, is the most persuasive advocate for a masculinist Tennyson, presenting “The Princess” as undertaking a project of “subsumption,” in which the words and demands of the women are “ingested, modified and incorporated by the patriarch” (46). In an article entitled: “Marginalized Musical Interludes: Tennyson's Critiques of Conventionality in ‘The Princess,’“ Alisa Clapp-Itnyre provides a representative case for the defence, presenting the lyrics as “pivotal feminist commentaries” that work to interrupt and deconstruct the male narrative (229). Herbert Tucker locates a third way, identifying the poem as a “textbook Victorian compromise” (Tennyson352). He argues that it “avoids taking a position on a hotly debated issue by taking up any number of positions” and characterizes this compromise, not as a commitment to portraying a complex contemporary issue with integrity, but as the result of Tennyson's not caring particularly either way: “neither the rallying of Victorian feminism” he writes, “nor the patriarchal status quo was sufficient stimulus to commitment” (352). In order to open up a new line of enquiry into “The Princess” I would like to look beyond the gender questions that continue to be batted back and forth amongst Tennyson's critics and to offer the figure of the child as an alternative and more powerful cultural, aesthetic and professional stimulus to Tennyson's poem.
GENDER, ROYALTY, AND SEXUALITY IN JOHN GOULD'SBIRDS OF AUSTRALIA
Authors: Smith Jonathan
Published: July 2007

WHEN THE BRITISH ORNITHOLOGISTand bird illustrator John Gould launched his monumental publication onThe Birds of Australialate in 1840, the cover of the serial parts bore the image of the lyre bird (Menura superba) and a prominent dedication, “by permission,” to the young and recently-married Queen Victoria (Correspondence2: 213; see Figure 4). A few months later, issuing the part with the plate and descriptive text for the lyre bird, Gould declaredMenura superba“an emblem for Australia among its birds” (Birds of Australiavol. 3, plate 14; see Figure 5). This visual juxtaposition of Victoria and the lyre bird also reflected an association between them in Gould's mind, the lyre bird serving as emblem not only for the Australian colonies but also for their Queen. The association became more explicit and was extended to include Victoria's Consort in the decades that followed, for althoughThe Birds of Australiawas completed in 1848, Gould issued irregular supplemental installments during the 1850s and 60s and published a two-volumeHandbook to the Birds of Australiain 1865. One of the first discoveries Gould announced and figured in theSupplementwas a new species of lyre bird, which he namedMenura albertiin 1850 to acknowledge Prince Albert's “personal virtues” and “liberal support.” In 1862, in a tribute likely inspired by the recent death of the Prince, Gould dividedMenura superbainto two species and christened the newly-created oneMenura victoriae, thereby providing his grieving queen with an avian namesake to accompany Albert's.
Ultrathin Carbon Support Films for High-Resolution Electron
Microscopy of Nanoparticles
Authors: Kim Young-Min , Kang Ji-Sun , Kim Ji-Soo , Jeung Jong-Man , Lee Jeong-Yong , Kim Youn-Joong
Published: July 2007

We introduce a simple preparation method for ultrathin carbon support
films that is especially useful for high-resolution electron microscopy
(HREM) of nanoparticles. Oxidized iron nanoparticles were used as a test
sample in a demonstration of this method. The film qualities are discussed
on the basis of electron-energy-loss spectroscopy (EELS) and image
analysis techniques such as thickness maps and histograms. We carried out
a comparison between the homemade and commercial film qualities. The
relative thickness of the homemade support films was 0.6 times less than
that of the commercial films, which was calculated from the EELS analysis,
whereas the thicknesses of both carbon support films varied within about
3%. The percentage of the observable area was about 67 ± 7.6% of
the support film. This was about twice as large as the commercial film (32
± 9.3%). The HREM image of the sample prepared with our support
film improved 9% in brightness and 15% in contrast compared with images
obtained with the commercial support.
Image Analysis of Food Microstructure. John C. Russ
Authors: Smith Bronwen
Published: July 2007

Image Analysis of Food Microstructure. John C. Russ. CRC
Press, Boca Raton, FL; 2005, 369 pages. ISBN 0-8493-2241-3

Understanding food microstructure is fundamental to understanding the
changes fresh fruit and vegetables undergo during development,
postharvest, and during processing and preservation treatments, such as
canning, drying, and freezing. Microstructure is also important in
manufactured foods and in the development of new types of foods to give
insight into the way in which ingredients respond when mixed with others
and how they compete for space in a volume. Microstructure is important
for food scientists because it gives rise to quality aspects, including
texture, color, and palatability of foods. Finding innovative ways to
examine food microstructure not only helps the fundamental understanding
but also allows us to solve problems for industry when products fail.
Phosphorylation of the Aspergillus oryzae Woronin body protein, AoHex1, by protein kinase C: evidence for its role in the multimerization and proper localization of the Woronin body protein
Authors: Juvvadi Praveen Rao , Maruyama Jun-ichi , Kitamoto Katsuhiko
Published: July 2007

Woronin body, a specialized peroxisome, is a unique organelle involved in septal pore sealing and protecting filamentous fungus from excessive cytoplasmic bleeding. We recently characterized the Aohex1 gene encoding the major protein of the Woronin body in the fungus Aspergillus oryzae. Although three-dimensional microscopy revealed plugging of the septal pore by Woronin body, the mechanism of its formation remains unknown. We report here a reduction in the oligomeric forms (dimeric and tetrameric) of AoHex1 upon λ-phosphatase treatment, which indicated that AoHex1 phosphorylation in vivo facilitates its oligomerization. Concomitant with the presence of a highly conserved predicted PKC (protein kinase C)-phosphorylatable site (Ser151), the recombinant AoHex1 was phosphorylated by PKC in vitro and the administration of the PKC inhibitors, bisindolylmaleimide I and chelerythrine, resulted in the reduction of the oligomeric forms of AoHex1 in vivo. While spherical dot-like Woronin bodies were visualized by expressing the dsred2–Aohex1 and egfp (enhanced green fluorescent protein)–Aohex1 constructs in A. oryzae, treatment with the PKC inhibitors caused an abnormal localization to ring-like structures. In addition to the reduced phosphorylation of the mutagenized recombinant AoHex1[S151A] (Ser151 to alanine substitution) by PKC in vitro, the overexpression of Aohex1[S151A] as dsred2 fusion against the wild-type background also showed reduction of the oligomeric forms of the endogenous AoHex1 and its perturbed localization to ring-like structures in vivo. In conclusion, the present study implicates the relevance of PKC-dependent phosphorylation of the Woronin body protein, AoHex1, for its multimerization and proper localization.
Regulation of p73-mediated apoptosis by c-Jun N-terminal kinase
Authors: Jones Emma V. , Dickman Mark J. , Whitmarsh Alan J.
Published: July 2007

The JNK (c-Jun N-terminal kinase)/mitogen-activated protein kinase signalling pathway is a major mediator of stress responses in cells, including the response to DNA damage. DNA damage also causes the stabilization and activation of p73, a member of the p53 family of transcription factors. p73, like p53, can mediate apoptosis by up-regulating the expression of pro-apoptotic genes, including Bax (Bcl2-associated X protein) and PUMA (p53 up-regulated modulator of apoptosis). Changes in p73 expression have been linked to tumour progression, particularly in neuroblastomas, whereas in tumours that feature inactivated p53 there is evidence that p73 may mediate the apoptotic response to chemotherapeutic agents. In the present study, we demonstrate a novel link between the JNK signalling pathway and p73. We use pharmacological and genetic approaches to show that JNK is required for p73-mediated apoptosis induced by the DNA damaging agent cisplatin. JNK forms a complex with p73 and phosphorylates it at several serine and threonine residues. The mutation of JNK phosphorylation sites in p73 abrogates cisplatin-induced stabilization of p73 protein, leading to a reduction in p73 transcriptional activity and reduced p73-mediated apoptosis. Our results demonstrate that the JNK pathway is an important regulator of DNA damage-induced apoptosis mediated by p73.
PIASy controls ubiquitination-dependent proteasomal degradation of Ets-1
Authors: Nishida Tamotsu , Terashima Motoko , Fukami Kiyoko , Yamada Yoshiji
Published: July 2007

The ETS transcription factor Ets-1 (E26 transformation-specific-1) plays a critical role in many physiological processes including angiogenesis, haematopoietic development and tumour progression. Its activity can be regulated by post-translational modifications, such as phosphorylation. Recently, we showed that Ets-1 is a target for SUMO (small ubiquitin-like modifier) modification and that PIASy [protein inhibitor of activated STAT (signal transducer and activator of transcription) Y], a specific SUMO-E3 ligase for Ets-1, represses Ets-1-dependent transcription. In the present study, we demonstrated that Ets-1 is degraded by the proteasome and that overexpression of PIASy increased the stability of endogenous and ectopically expressed Ets-1 protein by preventing proteasomal degradation. Moreover, knockdown of the endogenous PIASy expression by RNA interference reduced the protein level of endogenous Ets-1. The proteasome inhibitor MG132 reversed this effect. Deletion analysis showed that the TAD (transcriptional activation domain), which has been identified as the interaction domain with PIASy, was also required for Ets-1 ubiquitination and proteasomal degradation. However, the Ets-1 stabilization by PIASy was not due to reduced ubiquitination of Ets-1. Our results suggested that PIASy controls Ets-1 function, at least in part, by inhibiting Ets-1 protein turnover via the ubiquitin–proteasome system.
Identification of amino acid residues at the active site of endosialidase that dissociate the polysialic acid binding and cleaving activities in Escherichia coli K1 bacteriophages
Authors: Jakobsson Elina , Jokilammi Anne , Aalto Juha , Ollikka Pauli , Lehtonen Jukka V. , Hirvonen Harri , Finne Jukka
Published: July 2007

Endosialidase (endo-N-acetylneuraminidase) is a tailspike enzyme of bacteriophages specific for human pathogenic Escherichia coli K1, which specifically recognizes and degrades polySia (polysialic acid). polySia is also a polysaccharide of the capsules of other meningitis- and sepsis-causing bacteria, and a post-translational modification of the NCAM (neural cell-adhesion molecule). We have cloned and sequenced three spontaneously mutated endosialidases of the PK1A bacteriophage and one of the PK1E bacteriophage which display lost or residual enzyme activity but retain the binding activity to polySia. Single to triple amino acid substitutions were identified, and back-mutation constructs indicated that single substitutions accounted for only partial reduction of enzymic activity. A homology-based structural model of endosialidase revealed that all substituted amino acid residues localize to the active site of the enzyme. The results reveal the importance of non-catalytic amino acid residues for the enzymatic activity. The results reveal the molecular background for the dissociation of the polySia binding and cleaving activities of endosialidase and for the evolvement of ‘host range’ mutants of E. coli K1 bacteriophages.
Articulation between Neoliberal and State-Oriented Environmental Regulation: Fisheries Privatization and Endangered Species Protection
Authors: Mansfield Becky
Published: July 2007

This paper analyzes the relationship between state-oriented and neoliberal approaches to environmental regulation by examining simultaneous efforts to protect the endangered Steller sea lion and to privatize the fishery for Alaska pollock. Because these policies were designed and implemented at the same time and for the same industry, this case offers a unique opportunity to explore in detail not transitions from one type of policy regime to another but, rather, how these different policy regimes articulate. Rather than focusing on reregulation which occurs when neoliberal restructuring shifts away from traditional regulation while simultaneously developing new, market-oriented forms of regulation, this paper focuses on a different kind of reregulation which occurs when state-oriented and market-oriented approaches must coexist. Analysis of how regulators themselves write about the conjunction of these policies reveals that the two forms of regulation can be complementary. To the extent that neoliberal restructuring has environmental benefits, these are mediated through traditional environmental protections, and although restructuring is presented as a means of mitigating the negative economic effects of state-oriented regulation, these effects are quite consistent with the goals of restructuring. Further, this analysis also reveals the power of neoliberal discourse. Despite their own statements about the complex articulation of the policies, regulators attribute benefits to privatization and problems to state-oriented regulation. This case highlights the inability of neoliberalism to subsume its outsides—alternatives are already existing—but also highlights that these outsides can themselves come to support what they seem to oppose.
When Homes Become Prisons: The Relational Spaces of Postsocialist Energy Poverty
Authors: Buzar Stefan
Published: July 2007

In this paper I aim to develop a relational geographical interpretation of energy poverty in the postsocialist states of Eastern and Central Europe, through a field-based study of inadequately heated homes in the Macedonian cities of Skopje and Štip. According to the reviewed evidence, domestic energy deprivation simultaneously shapes, and is shaped by, the institutional relationships between policy actors at different levels of governance, and the day-to-day interactions between vulnerable households and the built environment. It is contingent on three sets of processes: the socioeconomic implications of energy reforms in postsocialism, the inadequate energy efficiency of the homes of energy-poor households, and the mismatch between housing needs and heating systems at the household level. As a result of such interdependencies, households may become ‘imprisoned’ in particular types of sociospatial arrangements that contribute to the emergence of poverty.
Which SMEs Use External Business Advice? A Multivariate Subregional Study
Authors: Johnson Steve , Webber Don J , Thomas Wayne
Published: July 2007

The authors examine factors that influence the propensity of a firm to take up external business support across four large English towns, using random effects nominal probit regression analysis to capture sector heterogeneity. The results suggest a strong positive association between the orientation of the firm towards growth and its propensity to use external business advice. ‘Push’ factors, including the existence of recruitment difficulties, are identified as key triggers to use business advice. These results provide valuable guidance to public policy organisations concerned with business development and competitiveness, and suggest a number of avenues for future research.
An essential role for Cdk1 in S phase control is revealed via chemical genetics in vertebrate cells
Authors: Hochegger Helfrid , Dejsuphong Donniphat , Sonoda Eiichiro , Saberi Alihossein , Rajendra Eeson , Kirk Jane , Hunt Tim , Takeda Shunichi
Published: July 2007

In vertebrates Cdk1 is required to initiate mitosis; however, any functionality of this kinase during S phase remains unclear. To investigate this, we generated chicken DT40 mutants, in which an analog-sensitive mutant cdk1 as replaces the endogenous Cdk1, allowing us to specifically inactivate Cdk1 using bulky ATP analogs. In cells that also lack Cdk2, we find that Cdk1 activity is essential for DNA replication initiation and centrosome duplication. The presence of a single Cdk2 allele renders S phase progression independent of Cdk1, which suggests a complete overlap of these kinases in S phase control. Moreover, we find that Cdk1 inhibition did not induce re-licensing of replication origins in G2 phase. Conversely, inhibition during mitosis of Cdk1 causes rapid activation of endoreplication, depending on proteolysis of the licensing inhibitor Geminin. This study demonstrates essential functions of Cdk1 in the control of S phase, and exemplifies a chemical genetics approach to target cyclin-dependent kinases in vertebrate cells.
Differences in C/EBPs in normal tissue and papillomas of the larynx
Authors: Jin L. , Yang G.‐Y. , Auborn K.
Published: July 2007

Abstract. Transcription factors belonging to the family of CAAT enhancer binding proteins (C/EBPs) programme differentiation in a wide variety of cells. We asked about the expression of C/EBPs in squamous epithelium. Using immunohistochem‐istry, C/EBPα and C/EBPβ were easily detected in tissue sections from normal larynx or laryngeal papillomas, benign tumours with a papillomavirus aetiology and characterized by abnormal differentiation. A temporal expression of these C/EBPs occured as keratinocytes differentiated. In both tissues, C/EBPβ appeared to be exclusively nuclear. In normal tissue, the greatest amount of C/EBPβ was present in the spinous layer, and much less occurred in the granular layer. The basal layer of the laryngeal papillomas contained the most C/EBPβ. Less was present in the spinous layer. Little C/EBPβ was in the granular layer. Much C/EBPα was in the cytoplasm in both tissues. In normal tissue, nuclear C/EBPα staining was virtually absent in the basal layer, and became present in the spinous layer. Nuclear C/EBPα was randomly distributed in all layers in papillomas. Using immunoblots and Southwestern blots, we detected abundant truncated isoforms of C/EBPα in the papillomas. Since differentiation of many tissues is determined by the relative amounts of different C/EBPs, our data supports a role for C/EBPs in the differentiation of squamous epithelium.
Prognostic significance of proliferative activity, DNA‐ploidy, p53 and Ki‐ras point mutations in colorectal liver metastases
Authors: Russo A. , Migliavacca M. , Bazan V. , Maturi N. , Morello V. , Dardanoni G. , Modica G. , Bazan P. , Albanese I. , Farina M. La , Tomasino R. M.
Published: July 2007

Abstract.Paired colorectal liver metastases (CLM) and normal tissue samples from a consecutive series of 36 patients were studied prospectively. MIB‐1 expression was studied by immunohistochemistry on paraffin‐embedded sections. DNA ploidy and S‐phase fraction (SPF) measurements were performed by flow cytometry on frozen tissues. Mutations within thep53(exons 5‐8) andc‐Ki‐ras(codons 12 and 13) genes were detected by PCR single‐strand conformation polymorphism analysis followed by sequencing. A high correlation was observed between the MIB‐1 LI and SPF value (rho=0·81; P<0·01). Moreover,p53gene mutations were associated with either high MIB‐1 LI and high SPF. In univariate analysis, SPF and MIB‐1 levels were related to risk of death. The association between overall survival and DNA‐ploidy orp53mutations did not reach statistical significance, but a slightly better survival was observed for patients either with DNA‐diploid tumours or without mutations (P=0·05 andP=0.06, respectively). SPF was shown by multivariate Cox model analysis to be an independent prognostic variable and thus it might be a useful prognostic factor in patients with CLM.
Differential binding of Escherichia coli DNA polymerases to the β‐sliding clamp
Authors: Maul Robert W. , Scouten Ponticelli Sarah K. , Duzen Jill M. , Sutton Mark D.
Published: July 2007

Escherichia coli strains expressing the mutant β159‐sliding clamp protein (containing both a G66E and a G174A substitution) are temperature sensitive for growth and display altered DNA polymerase (pol) usage. We selected for suppressors of the dnaN159 allele able to grow at 42°C, and identified four intragenic suppressor alleles. One of these alleles (dnaN780) contained only the G66E substitution, while a second (dnaN781) contained only the G174A substitution. Genetic characterization of isogenic E. coli strains expressing these alleles indicated that certain phenotypes were dependent upon only the G174A substitution, while others required both the G66E and G174A substitutions. In order to understand the individual contributions of the G66E and the G174A substitution to the dnaN159 phenotypes, we utilized biochemical approaches to characterize the purified mutant β159 (G66E and G174A), β780 (G66E) and β781 (G174A) clamp proteins. The G66E substitution conferred a more pronounced effect on pol IV replication than it did pol II or pol III, while the G174A substitution conferred a greater effect on pol III and pol IV than it did pol II. Taken together, these findings indicate that pol II, pol III and pol IV interact with distinct, albeit overlapping surfaces of the β clamp.
Purification and characterization of a novel nitrile hydratase from Rhodococcus sp. RHA1
Authors: Okamoto Sachi , Eltis Lindsay D.
Published: July 2007

The microbial degradation of nitriles is of interest for bioremediation and green chemistry. We demonstrated that the soil bacterium Rhodococcus sp. RHA1 utilizes a range of nitriles, including acetonitrile, as growth substrates. Proteomic analysis identified 13 proteins that were more abundant in acetonitrile‐grown cells, including an aliphatic amidase and a protein with no known homologue. Purification of a nitrile hydratase (NHase) from acetonitrile‐grown cells identified the unknown protein as the β subunit of a two‐subunit NHase. Sequence analysis revealed that the genes encoding the amidase (anhC) and the NHase (anhAB) occur in a 12.8 kbp cluster located on plasmid pRHL2. The anh gene cluster also encodes an acetyl‐CoA hydrolase, transcriptional regulators, a putative cobalt transporter and a protein of unknown function. Striking features of the NHase include the amino acid sequence identity (32%) and large size (63 and 56 kDa) of the α and β subunits, as well as the enzyme's metal ion content (one cobalt, two copper and one zinc). The enzyme possessed similar specificities for acetonitrile and propionitrile (kcat/Km∼7 mM−1 s−1) followed by acrylonitrile and butyronitrile. We propose that this acetonitrile hydratase (ANHase) represents the first member of a previously unknown class of NHases.
In Active Chronic Rheumatoid Arthritis, Dipeptidyl Peptidase IV Density is Increased on Monocytes and CD4+ T lymphocytes
Authors: Ellingsen T. , Hornung N. , Møller B. K. , Hjelm‐Poulsen J. , Stengaard‐Pedersen K.
Published: July 2007

The effect of low‐dose methotrexate (MTX) treatment on the CD26 density on circulating monocytes and CD4+ T lymphocytes or levels of soluble CD26 (sCD26) has not yet been described in rheumatoid arthritis (RA). While CD26 in T lymphocytes is involved in the activation and proliferation of T lymphocytes, little is known of the role of CD26 in monocytes as it has only recently been localized to monocytes. We analysed the CD26 density by flow cytometry and levels of sCD26 in plasma before initiation of MTX treatment and 12 weeks later. This was done on 34 RA patients fulfilling the 1987 American College of Rheumatology (ACR) criteria followed for 16 weeks after starting MTX treatment. CD26 density on monocytes was increased in RA patients compared with healthy controls before MTX treatment (P < 0.01). After 12 weeks of MTX treatment, the CD26 density on monocytes decreased significantly in the ACR‐50% group (P = 0.03), but not in the ACR‐20% and the non‐responder group (P = 0.15 and 0.87). The increased CD26 density on CD4+ T lymphocytes (P < 0.01) was unaffected by the reduction in disease activity in relation to MTX treatment. The percentage of monocytes and CD4+ T lymphocytes among peripheral blood circulating mononuclear cells did not change during MTX treatment. No effect of MTX treatment was observed on the plasma levels of sCD26. Active chronic RA is characterized by enhanced CD26 density on circulating monocytes and CD4+ T lymphocytes. MTX treatment decreased CD26 density on monocytes in the ACR‐50% responder group and was associated with decreased disease activity. The enhanced CD26 density on CD4+ T lymphocytes was uninfluenced by MTX treatment.
Characterization of the Spleen B‐Cell Compartment at the Early and Late Blood‐Stage Plasmodium chabaudi Malaria
Authors: Castillo‐Méndez S. I. , Zago C. A. , Sardinha L. R. , Freitas do Rosário A. P. , Álvarez J. M. , D’Império Lima M. R.
Published: July 2007

Abstract Polyclonal B‐cell activation is a feature of the early spleen cell response to blood‐stage Plasmodium chabaudi malaria. Immunity to blood‐stage malaria is guaranteed by the generation of B cells able to produce parasite‐specific antibodies mainly from the immunoglobulin (Ig)G2a isotype. In the present study, we characterized the spleen B‐cell compartment during blood‐stage P. chabaudi infection. The numbers of B220+ and B220LOW CD138+ (plasma) cells increased sharply between days 4 and 7 post‐infection (p.i.). At this time B220+ cells expressed surface (s)IgM, but nearly all B220LOW CD138+ cells showed concomitantly intracellular (i)IgM and IgG2a. Both follicular and marginal zone B cells were activated expressing high amounts of CD69. At day 40 p.i., B220LOW CD138+ cell population was still increased but, differently from acute infection, 61.1% of these cells were positive for iIgG2a while only 14.2% expressed iIgM. Moreover, at days 20 and 40 p.i., 29.2% and 13.0% of B220+ cells expressed sIgG2a, respectively. According to cell size and expression of CD80, CD86, CD11b, CD44 and CD38, B220+ sIgG2a+ cells had a phenotype characteristic of activated/memory B cells. Furthermore, 14.1% of B220+ sIgG2a+ cells at day 30 p.i. expressed a marginal zone B‐cell phenotype. Importantly, B cells from 40‐day‐infected mice were very efficient in presenting parasite antigens leading to proliferation of both CD4+ and CD8+ cells. Our results contribute for understanding the dynamics of B cells during P. chabaudi infection, underlying the mechanisms of antigen presentation and antibody production, which are essential for the acquisition of protective immunity against malaria.
The Role of Microparticles in Inflammation and Thrombosis
Authors: Ardoin S. P. , Shanahan J. C. , Pisetsky D. S.
Published: July 2007

Microparticles (MP) are small membrane‐bound vesicles that circulate in the peripheral blood and play active roles in thrombosis, inflammation and vascular reactivity. While MP can be released from nearly every cell type, most investigation has focused on MP of platelet, leucocyte and endothelial cell origin. Cells can release MP during activation or death. Flow cytometry is the usual method to quantify MP; the small size of these structures and lack of standardization in methodology complicate measurement. As MP contain surface and cytoplasmic contents of the parent cells and bear phosphatidylserine, antibodies to specific cell surface markers and annexin V can be used for identification. Through various mechanisms, MP participate in haemostasis and have procoagulant potential in disease. MP contribute to inflammation via their influence on cell–cell interactions and cytokine release, and MP also function in mediating vascular tone. In several disease states characterized by inflammation and vascular dysfunction, MP subpopulations are elevated, correlate with clinical events, and may have important roles in pathogenesis. In the rheumatic conditions such as rheumatoid arthritis and systemic lupus erythematosus, MP are potentially important markers of disease activity and have an increasingly recognized role in immunopathogenesis. It is clear that MP play an important role in atherosclerosis, and study of these structures may provide insight into the link between chronic inflammatory conditions and accelerated atherosclerosis. As biomarkers, MP allow access to usually inaccessible tissues such as the endothelium. Further research will hopefully lead to interventions targeting MP release and function.
A novel HLA‐B*46 allele, B*4609, identified by sequence‐based typing in a Chinese donor
Authors: Zhang K.‐L. , Li J.‐P. , Zhang X. , Chen Y. , Liu X.‐Z.
Published: July 2007

A novel human leukocyte antigen‐B allele, B*4609, has been identified. The B*4609 allele has one nucleotide change from the closest matching allele B*460101 resulting in an amino acid change from E (GAG) to V (GTG) at codon 176.
HLA‐B*0749N: the first HLA‐B*07 null allele
Authors: Perrier P. , Dormoy A. , Proust B. , Froelich N. , Bastien A.
Published: July 2007

In the present article, we report the identification of the first HLA‐B*07 null allele found in a Polish patient awaiting a kidney allograft. A discrepant result obtained between serological typing (HLA‐B “blank”) and high‐resolution molecular typing using PCR‐SSP method (HLA‐B*070201 allele) suggested the presence of a null allele. Genomic DNA sequencing of the HLA‐B*07 allele revealed a single nucleotide substitution at the 3′ end of the exon 4 leading to a premature stop codon.