bluuebunny/crossref_metadata_2025 huggingface dataset:
Enrichment of anaerobic methanotrophs in sulfate‐reducing membrane bioreactors
Authors: Meulepas Roel J.W. , Jagersma Christian G. , Gieteling Jarno , Buisman Cees J.N. , Stams Alfons J.M. , Lens Piet N.L.
Published: May 2009

Anaerobic oxidation of methane (AOM) in marine sediments is coupled to sulfate reduction (SR). AOM is mediated by distinct groups of archaea, called anaerobic methanotrophs (ANME). ANME co‐exist with sulfate‐reducing bacteria, which are also involved in AOM coupled SR. The microorganisms involved in AOM coupled to SR are extremely difficult to grow in vitro. Here, a novel well‐mixed submerged‐membrane bioreactor system is used to grow and enrich the microorganisms mediating AOM coupled to SR. Four reactors were inoculated with sediment sampled in the Eckernförde Bay (Baltic Sea) and operated at a methane and sulfate loading rate of 4.8 L L−1 day−1 (196 mmol L−1 day−1) and 3.0 mmol L−1 day−1. Two bioreactors were controlled at 15°C and two at 30°C, one reactor at 30°C contained also anaerobic granular sludge. At 15°C, the volumetric AOM and SR rates doubled approximately every 3.8 months. After 884 days, an enrichment culture was obtained with an AOM and SR rate of 1.0 mmol g day−1 (286 µmol g day−1). No increase in AOM and SR was observed in the two bioreactors operated at 30°C. The microbial community of one of the 15°C reactors was analyzed. ANME‐2a became the dominant archaea. This study showed that sulfate reduction with methane as electron donor is possible in well‐mixed bioreactors and that the submerged‐membrane bioreactor system is an excellent system to enrich slow‐growing microorganisms, like methanotrophic archaea. Biotechnol. Bioeng. 2009; 104: 458–470 © 2009 Wiley Periodicals, Inc.
Morphology of Barium Sulfate Crystals from Seeded Precipitation
Authors: Steyer C. , Sundmacher K.
Published: May 2009

It is shown that for seeded precipitation, the morphology and the location of active growth sites of the seed crystals depend on the conditions in which they were produced in terms of supersaturation, ion ratio of reactants, and feed rate. Further, the properties of the seed crystals influence the morphology and, hence, the size of the seeded precipitated particles. The reaction system is barium sulfate from barium chloride and potassium sulfate in a semi‐batch stirred tank reactor.
Penetration of Organic Liquids into Dry Portland Cement Mortar under Ambient and High Pressure
Authors: Seeger A. , Brickmann J. , Luft G.
Published: May 2009

The penetration depths (PDs) of 81 different organic liquids into uncracked dry cement mortar were measured by a suction test at ambient pressure. The physicochemical properties of the liquids (viscosity (η), surface tension (σ), density (ρ), partition coefficient (logP), and molecular volume) were correlated with their penetration depth at normal pressure. It was found that viscosity has the main impact on the penetration. It could be shown by dimensional analysis that the penetration depth at ambient pressure is proportional to the parameter (σρ/η2)1/4. Furthermore, a device to measure the penetration at high pressure up to 50 bar was set up. It was experimentally found that the natural logarithm of the PD at constant time is approximately proportional to the natural logarithm of the applied pressure. A method was elaborated to extrapolate the penetration depth at normal pressure from one single high‐pressure measurement. The advantage of this technique is the significantly shorter measurement time for the high‐pressure test of 15 min up to 1 h compared to the usual tests at normal pressure which require 72 h.
Enantioselective Recognition and Separation by a Homochiral Porous Lamellar Solid Based on Unsymmetrical Schiff Base Metal Complexes
Authors: Yuan Guozan , Zhu Chengfeng , Xuan Weimin , Cui Yong
Published: May 2009

Our Schiff has come in: A homochiral porous lamellar solid based on chiral unsymmetrical Schiff base metal complexes was assembled by using coordination and hydrogen bonds (see picture). The host features a flexible helical framework and chiral amphiphilic channel surfaces capable of multiple interactions with guest species.

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A homochiral lamellar supramolecular host system has been developed by treating 3‐[(E)‐{[(1R,2R)‐2‐aminocyclohexyl]imino}methyl]‐4‐hydroxybenzoic acid (H2L) with copper nitrate and characterized by a variety of techniques including microanalysis, IR spectroscopy, thermogravimetric analysis (TGA), circular dichroism (CD) spectroscopy, and powder and single‐crystal X‐ray diffraction. Tridentate Schiff base L ligands link adjacent metal centers to form 1D coordination polymeric chains using tridentate N2O donors and carboxylate groups, while interchain metal–oxygen and hydrogen‐bonding interactions further link 1D polymeric chains to a porous lamellar solid. The host features a flexible helical framework for guest inclusions and chiral amphiphilic channel surfaces lined with amine hydrogen atoms and aliphatic groups capable of multiple interactions with guest species. It allows for the development of an efficient approach for highly enantioselective separation of racemic secondary alcohols by inclusion crystallization followed by distillation (>99.5 % ee). In addition, the host including different alcohols exhibits guest‐responsive ferroelectric behavior.
Photonucleophilic Addition of the ε‐Amino Group of Lysine to a Triflusal Metabolite as a Mechanistic Key to Photoallergy Mediated by the Parent Drug
Authors: Montanaro Sara , Lhiaubet‐Vallet Virginie , Jiménez M. Consuelo , Blanca Miguel , Miranda Miguel Angel
Published: May 2009

A mechanism for triflusal‐induced photoallergyinvolving complexation of 2‐hydroxy‐4‐trifluoromethylbenzoic acid with site I of human serum albumin and subsequent formation of a covalent adduct by photoreaction between a metabolite and a neighboring lysine residue is proposed. This is supported by the observed photobinding to poly‐L‐lysine. Thereby, a photoantigen is generated, which is a likely trigger of the immune response.

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The goal of the work presented herein is to gain deeper insight into the molecular basis of photoallergy mediated by triflusal through its active metabolite, 2‐hydroxy‐4‐trifluoromethylbenzoic acid (HTB). For this purpose, the interaction between HTB and human serum albumin (HSA) was investigated by fluorescence and laser flash photolysis to monitor inclusion into the protein binding sites through variation in the excited‐state properties. A remarkable lengthening of HTB triplet lifetime in the presence of HSA was observed. The use of oleic acid as a displacement probe clearly suggests the preference for dark binding in site I. The mechanism of photobinding was studied by irradiation of HTB in the presence of amino acids, and, in the case of lysine, a photoadduct was detected that arises from nucleophilic attack by the ε‐amino group to the trifluoromethyl substituent of HTB. Accordingly, photobinding of the metabolite to poly‐L‐lysine was also observed. Overall, these results are consistent with a mechanism for triflusal photoallergy involving complexation of HTB to site I of HSA and subsequent formation of a covalent photoadduct with one neighboring lysine residue.
Meropenem–Clavulanate: A New Strategy for the Treatment of Tuberculosis?
Authors: Holzgrabe Ulrike
Published: May 2009

The Great White Plague: Mycobacterium tuberculosis, the bacteria causing tuberculosis, is a continuing threat to global health through the emergence of resistant strains and the lack of novel therapeutic agents. Recently reported results on this important work are highlighted.

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Recent Advances in Solution NMR: Fast Methods and Heteronuclear Direct Detection
Authors: Felli Isabella C. , Brutscher Bernhard
Published: May 2009

NMR spectroscopy for the molecular life sciences: Two areas of recent active research [fast methods and direct detection of low‐γ nuclei (see schematic)] are reviewed herein. These are powerful new tools for structural characterization of short‐lived molecules, large and intrinsically unstructured proteins, paramagnetic systems, as well as for the study of molecular kinetic processes at atomic resolution.

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Today, NMR spectroscopy is the technique of choice to investigate molecular structure, dynamics, and interactions in solution at atomic resolution. A major limitation of NMR spectroscopy for the study of biological macromolecules such as proteins, nucleic acids, and their complexes, has always been its low sensitivity, a consequence of the weak magnetic spin interactions. Therefore many efforts have been invested in the last decade to improve NMR instrumentation in terms of experimental sensitivity. As a result of these efforts, the availability of high‐field magnets, cryogenically cooled probes, and probably in the near future hyperpolarization techniques, the intrinsic NMR sensitivity has increased by at least one order of magnitude. Stimulated by new challenges in the life sciences, these technical improvements have triggered the development of new NMR methods for the study of molecular systems of increasing size and complexity. Herein, we focus on two examples of recently developed NMR methodologies. First, advanced multidimensional data acquisition schemes provide a speed increase of several orders of magnitude. Second, NMR methods based on the direct detection of low‐gamma nuclei present a new spectroscopic tool, highly complementary to conventional NMR techniques. These new methods provide powerful new NMR tools for the study of short‐lived molecules, large and intrinsically unstructured proteins, paramagnetic systems, as well as for the characterization of molecular kinetic processes at atomic resolution. These examples illustrate how NMR is continuously adapting to the new challenges in the life sciences, with the focus shifting from the characterization of single biomolecules to an integrated view of interacting molecular networks observed at varying levels of biological organization.
Limitations of Induced Folding in Molecular Recognition by Intrinsically Disordered Proteins
Authors: Hazy Eszter , Tompa Peter
Published: May 2009

Intrinsically disordered proteins exist and function without well‐defined three‐dimensional structures and are common in proteomes where they carry out essential functions. Herein, evidence for their lack of structure and the major functional benefits that this confers, are surveyed. An example is Tβ4, a sequence that is disordered until it binds to G‐actin, when it adopts an ordered conformation (see picture).

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Intrinsically disordered proteins (IDPs) exist and function without well‐defined three‐dimensional structures, thus they defy the classical structure–function paradigm. These proteins are common in proteomes, and they carry out essential functions often related to signalling and regulation of transcription. Herein, the experimental evidence for their lack of structure and the major functional benefits that structural disorder confers, are surveyed. It is shown that IDPs often function by molecular recognition, in which either short motifs, or domain‐sized disordered segments are used for partner recognition. In both cases, the binding segment undergoes induced folding and it attains an ordered structure. This folding‐upon‐binding scenario suggests that the function of IDPs can be interpreted in terms of the static structural view of the classical paradigm. New developments in the field, however, suggest that folding upon binding is limited, and many IDPs preserve a significant level of disorder in the bound state, a phenomenon termed fuzziness. In addition, IDPs may structurally adapt to different partners with different functional outcomes, resulting in promiscuity in function termed moonlighting. It is suggested that a new model describing the structure–function relationship of IDPs has to encompass such structural and functional promiscuity inherent in the disordered state of IDPs.
Epitope‐tagging Math5 and Pou4f2: New tools to study retinal ganglion cell development in the mouse
Authors: Fu Xueyao , Kiyama Takae , Li Renzhong , Russell Mark , Klein William H. , Mu Xiuqian
Published: May 2009

Although immunological detection of proteins is used extensively in retinal development, studies are often impeded because antibodies against crucial proteins cannot be generated or are not readily available. Here, we overcome these limitations by constructing genetically engineered alleles for Math5 and Pou4f2, two genes required for retinal ganglion cell (RGC) development. Sequences encoding a peptide epitope from haemagglutinin (HA) were added to Math5 or Pou4f2 in frame to generate Math5HA and Pou4f2HA alleles. We demonstrate that the tagged alleles recapitulated the wild‐type expression patterns of the two genes, and that the tags did not interfere with the function of the cognate proteins. In addition, by co‐staining, we found that Math5 and Pou4f2 were transiently co‐expressed in newly born RGCs, unequivocally demonstrating that Pou4f2 is immediately downstream of Math5 in RGC formation. The epitope‐tagged alleles provide new and useful tools for analyzing gene regulatory networks underlying RGC development. Developmental Dynamics 238:2309–2317, 2009. © 2009 Wiley‐Liss, Inc.
CTLA‐4 is required by CD4+CD25+ Treg to control CD4+ T‐cell lymphopenia‐induced proliferation
Authors: Sojka Dorothy K. , Hughson Angela , Fowell Deborah J.
Published: May 2009

CTLA‐4 is constitutively expressed by CD4+CD25+Foxp3+ Treg but its precise role in Treg function is not clear. Although blockade of CTLA‐4 interferes with Treg function, studies using CTLA‐4‐deficient Treg have failed to reveal an essential requirement for CTLA‐4 in Treg suppression in vivo. Conditional deletion of CTLA‐4 in Foxp3+ T cells disrupts immune homeostasis in vivo but the immune processes disrupted by CTLA‐4 deletion have not been determined. We demonstrate that Treg expression of CTLA‐4 is essential for Treg control of lymphopenia‐induced CD4 T‐cell expansion. Despite IL‐10 expression, CTLA‐4‐deficient Treg were unable to control the expansion of CD4+ target cells in a lymphopenic environment. Moreover, unlike their WT counterparts, CTLA‐4‐deficient Treg failed to inhibit cytokine production associated with homeostatic expansion and were unable to prevent colitis. Thus, while Treg developing in the absence of CTLA‐4 appear to acquire some compensatory suppressive mechanisms in vitro, we identify a non‐redundant role for CTLA‐4 in Treg function in vivo.
Early simultaneous production of intranodal CD4 Th2 effectors and recirculating rapidly responding central‐memory‐like CD4 T cells
Authors: Serre Karine , Mohr Elodie , Toellner Kai‐Michael , Cunningham Adam F. , Bird Roger , Khan Mahmood , MacLennan Ian C. M.
Published: May 2009

This study characterizes the diversity of CD4 Th cells produced during a Th2 response in vivo. Kinetics of effector and memory cell differentiation by mouse OVA‐specific CD4 T cells was followed during primary responses to alum‐precipitated OVA. The complexity of the CD4 T response was assessed in nodes draining and distant from the site of immunization for phenotype, location and function. By 3 days IL‐4‐producing effector CD4 T cells developed in the draining node and a proportion of the responding cells had migrated to B‐cell follicles, while yet others had left the draining node. Some of these early migrant cells were recirculating cells with a central memory phenotype. These had divided four or more times in the draining node before migrating to distant nodes not exposed to antigen. We questioned the responsiveness of these early central‐memory‐like cells on secondary antigen challenge at sites distant to the primary immunization. They re‐entered cell cycle and migrated to B‐cell follicles, much more rapidly than naïve CD4 T cells and could still be induced to produce IL‐4. Their production and survival were independent of the starting frequency of antigen‐specific CD4 T cells. Thus intranodal effector cells and recirculating, rapidly responding central‐memory‐like cells emerged simultaneously from the third day of a primary Th2 response.
Antigens expressed by myelinating glia cells induce peripheral cross‐tolerance of endogenous CD8+ T cells
Authors: Schildknecht Anita , Probst Hans Christian , McCoy Kathy D. , Miescher Iris , Brenner Corinne , Leone Dino P. , Suter Ueli , Ohashi Pamela S. , van den Broek Maries
Published: May 2009

Auto‐reactivity of T cells is largely prevented by central and peripheral tolerance. Nevertheless, immunization with certain self‐antigens emulsified in CFA induces autoimmunity in rodents, suggesting that tolerance to some self‐antigens is not robust. To investigate the fate of nervous system‐specific CD8+ T cells, which only recently came up as being important contributors for MS pathogenesis, we developed a mouse model that allows inducible expression of lymphocytic choriomeningitis virus‐derived CD8+ T‐cell epitopes specifically in oligodendrocytes and Schwann cells, the myelinating glia of the nervous system. These transgenic CD8+ T‐cell epitopes induced robust tolerance of endogenous auto‐reactive T cells, which proved thymus‐independent and was mediated by cross‐presenting bone‐marrow‐derived cells. Immunohistological staining of secondary lymphoid organs demonstrated the presence of glia‐derived antigens in DC, suggesting that peripheral tolerance of CD8+ T cells results from uptake and presentation by steady state DC.
Modeling of lifting‐device aerodynamics using the actuator surface concept
Authors: Sibuet Watters Christophe , Masson Christian
Published: May 2009

The actuator surface (AS) concept and its implementation within a differential, Navier–Stokes control volume finite‐element method (CVFEM) are presented in this article. Inspired by vortex and actuator disk methods, the AS concept consists of using porous surfaces carrying velocity and pressure discontinuities to model the action of lifting surfaces on the flow. The underlying principles and mathematics associated with AS are first reviewed, as well as their implementation in a CVFEM. Results are presented for idealized 2D cases with analytical solutions, as well as for the 3D cases of a finite wing and an experimental wind turbine. In the case of the finite wing, wake induction is well handled by the model with accurate predictions of induced angles and drag when compared with the Prandtl lifting line model. Comparisons with volume force approaches, often used to model the action of propellers or wind turbine blades in a simplified analysis, show that the AS concept has some interesting advantages in terms of accuracy and respect of flow physics. This new approach is easy and rapid to embed in most computational fluid dynamics (CFD) methods. It is applicable to a wide range of problems involving thin lifting devices like finite wings, propellers, helicopter or wind turbine blades. Copyright © 2009 John Wiley & Sons, Ltd.
Finite volume simulation of viscous free surface waves using the Cartesian cut cell approach
Authors: Bai W. , Mingham C. G. , Causon D. M. , Qian L.
Published: May 2009

The application of the Cartesian cut cell approach in the numerical simulation of two‐dimensional viscous free surface flows is described. The Arbitrary Lagrangian–Eulerian method is adopted to update the moving free water surface in a semi‐Lagrangian scheme, in which a finite volume method of second‐order accuracy in space is used for solving the flow field based on an Eulerian description at each time step. The cut cell approach is employed to track the free surface and solid boundaries across a stationary background Cartesian grid covering the whole fluid, air and solid regions. In this approach, the cells full of air and solid are not calculated explicitly, and apart from the fluid cells, cut cells and merged cells are treated separately in terms of corresponding boundary conditions. In order to validate the present numerical method, current flow past a circular cylinder at various low Reynolds numbers and wave sloshing in a rectangular container are tested first. Further numerical results are obtained for the propagation of regular waves and a wave passing over a submerged dike. The model is also applied to the simulation of radiation waves induced by a forced oscillating submerged circular cylinder. The results indicate that the present numerical model using the Cartesian cut cell approach is highly efficient for solving the wave fields, and fully automatic for generating boundary fitted meshes. These features are particularly useful for moving boundary problems in a larger computational domain and with a longer simulation time. Copyright © 2009 John Wiley & Sons, Ltd.
Applying cognitive adjustment theory to cross‐cultural training for global virtual teams
Authors: Brandl Julia , Neyer Anne‐Katrin
Published: May 2009

Global virtual teams are faced with the challenge of developing trust in a technology‐mediated context to overcome anxiety and uncertainty in their interactions. Research shows that adjustment is a function of an individual's ability to manage his or her anxiety and uncertainty in an unknown context (Gudykunst, 1995). We propose that the type of cross‐cultural training (CCT) received can influence cognitive adjustment in global virtual teams. Building on phenomenology and sense‐making theory, we argue that training needs to develop global virtual team members' capabilities in dealing with the unknown rather than providing ready‐made concepts of cultures. Managerial implications of our theoretical discussion of cognitive adjustment and how CCT influences it are discussed, as are directions for future research. © 2009 Wiley Periodicals, Inc.
Preventing burnout: the effects of LMX and mentoring on socialization, role stress, and burnout
Authors: Thomas Christopher H. , Lankau Melenie J.
Published: May 2009

Halbesleben and Buckley's (2004) review of burnout research suggested a lingering need to examine the relationship between social support and burnout. We address that need by investigating Leader‐Member Exchange (LMX) and mentoring as sources of workplace social support. We used data from 422 employees in a health care setting to test three structural models investigating the direct and indirect effects of LMX, supervisory mentoring, and nonsupervisory mentoring on organizational socialization, role stress, and burnout. Results suggest that high‐LMX supervisors and nonsupervisory mentors serve as resources that minimize emotional exhaustion through increased socialization and decreased role stress. This study advances the literature on burnout by clarifying the effects of different types of social support in reducing burnout. © 2009 Wiley Periodicals, Inc.
Enhanced expression of Annexin A4 in clear cell carcinoma of the ovary and its association with chemoresistance to carboplatin
Authors: Kim Ayako , Enomoto Takayuki , Serada Satoshi , Ueda Yutaka , Takahashi Tsuyoshi , Ripley Barry , Miyatake Takashi , Fujita Masami , Lee Chun Man , Morimoto Koji , Fujimoto Minoru , Kimura Tadashi , Naka Tetsuji
Published: May 2009

Clear cell carcinoma (CCC) of the ovary is known to be highly resistant to platinum‐based chemotherapy. The purpose of our study was to identify a candidate protein that is associated with chemoresistance of CCC and to investigate the specific mechanism of chemoresistance conferred by the identified protein. Enhanced expression of Annexin A4 (Anx A4) was identified in ovarian CCC cells using 2‐D differential gel electrophoresis (2D‐DIGE) and mass spectrometry. Anx A4 levels were elevated in CCC cells compared with non‐CCC cells as determined by real‐time RT‐PCR and Western blot analysis. Immunohistochemical analysis of Anx A4 was performed in 126 epithelial ovarian cancer tissue samples and demonstrated significantly elevated levels of Anx A4 protein levels in ovarian CCC tumors compared with ovarian serous and endometrioid tumors (p < 0.01). Anx A4‐transfected ovarian non‐CCC cells were more resistant to carboplatin (IC50 = 42 μM) compared with control cells (IC50 = 23 μM) as determined by modified MTT assay. Intracellular platinum levels were significantly lower in Anx A4‐transfected cells compared with control cells after carboplatin treatment (p = 0.0020) and after an additional 360 min of carboplatin‐free incubation (p = 0.0004), as measured by atomic absorption spectrophotometry. Expression of Anx A4 is elevated in ovarian CCC tumors and is associated with chemoresistance in cultured ovarian cancer cells. These results demonstrate that Anx A4 confers chemoresistance in ovarian cancer cells in part by enhancing drug efflux. Thus, Anx A4 may represent a novel therapeutic target of chemoresistance in patients with ovarian CCC. © 2009 UICC
Distinct progression‐associated expression of tumor and stromal MMPs in HaCaT skin SCCs correlates with onset of invasion
Authors: Vosseler Silvia , Lederle Wiltrud , Airola Kristiina , Obermueller Eva , Fusenig Norbert E. , Mueller Margareta M.
Published: May 2009

Matrix metalloproteinases (MMPs) are critically involved in tumor invasion and metastasis. However, failure of broad spectrum MMP inhibitors in clinical trials emphasizes the need for detailed analyses of the specific role of different MMPs in tumor malignancy. Using HaCaT‐keratinocyte clones representing distinct stages in skin squamous cell carcinoma (SCC) progression, we demonstrate the expression of specific tumor and stroma‐derived MMPs with the onset and maintenance of tumor invasion. Although MMP‐9‐positive leukocytes are present in benign and malignant tumor transplants at the onset of stromal activation and angiogenesis, mRNA expression of stroma‐derived MMP‐9 as well as MMP‐2, −13 and −14 is exclusively found in enhanced malignant tumor transplants. Their expression initiates with the onset of invasion, whereas being absent in early noninvasive stages of malignant transplants. In addition, a high expression of tumor‐derived MMP‐1, −2 and −14 contributes to malignant and invasive tumor growth. However, stroma‐derived MMP‐3 is exclusively restricted to very late‐stage invasive and malignant transplants. The functional contribution of these proteases to invasive growth is supported by the gelatinolytic activity in the tumor transplants that again initiates with the onset of invasive growth suggesting a crucial role of MMP‐2, −9, −13 and −14 for the establishment of a reactive stroma that promotes tumor invasion. These data demonstrate a complex cooperation of distinct tumor and stroma‐derived MMPs in the establishment of malignant tumors and provide the basis for a more specific use of highly selective MMP inhibitors during distinct stages of tumor progression. © 2009 UICC
Computing free energy hypersurfaces for anisotropic intermolecular associations
Authors: Strümpfer Johan , Naidoo Kevin J.
Published: May 2009

We previously used an adaptive reaction coordinate force biasing method for calculating the free energy of conformation (Naidoo and Brady, J Am Chem Soc 1999, 121, 2244) and chemical reactions (Rajamani et al., J Comput Chem 2003, 24, 1775) amongst others. Here, we describe a generalized version able to produce free energies in multiple dimensions, descriptively named the free energies from adaptive reaction coordinate forces method. To illustrate it, we describe how we calculate a multidimensional intermolecular orientational free energy, which can be used to investigate complex systems such as protein conformation and liquids. This multidimensional intermolecular free energy W(r, θ1, θ2, ϕ) provides a measure of orientationally dependent interactions that are appropriate for applications in systems that inherently have molecular anisotropic features. It is a highly informative free energy volume, which can be used to parameterize key terms such as the Gay‐Berne intermolecular potential in coarse grain simulations. To demonstrate the value of the information gained from the W(r, θ1, θ2, ϕ) hypersurfaces we calculated them for TIP3P, TIP4P, and TIP5P dimer water models in vacuum. A comparison with a commonly used one‐dimensional distance free energy profile is made to illustrate the significant increase in configurational information. The W(r) plots show little difference between the three models while the W(r, θ1, θ2, ϕ) hypersurfaces reveal the underlying energetic reasons why these potentials reproduce tetrahedrality in the condensed phase so differently from each. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Projective modules over polynomial rings: a constructive approach
Authors: Barhoumi S. , Lombardi H. , Yengui I.
Published: May 2009

We give a constructive proof of the fact that finitely generated projective modules over a polynomial ring with coefficients in a Prüfer domain R with Krull dimension ≤ 1 are extended from R. In particular, we obtain constructively that finitely generated projective R[X1, …, Xn ]‐modules, where R is a Bezout domain with Krull dimension ≤ 1, are free. Our proof is essentially based on a dynamical method for decreasing the Krull dimension and a constructive rereading of the original proof given by Maroscia and Brewer & Costa. Moreover, we obtain a simple constructive proof of a result due to Lequain and Simis stating that finitely generated modules over R[X1, …, Xn ], n ≥ 2, are extended from R if and only if this holds for n = 1, where R is an arithmetical ring with finite Krull dimension (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TV optimization and graph‐cuts
Authors: Darbon J. , Lefebvre S. , Chan T.F. , Esedoglu S.
Published: May 2009

This paper describes some links between the minimization of the Total Variation and the minimization of some binary energies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Methods and system of functional programming for supporting supercomputing
Authors: Kasyanov V.
Published: May 2009

In the paper, the functional programming system SFP being under development at the Institute of Informatics Systems in Novosibirsk is considered. The SFP system is aimed at supporting development of parallel computing applications that still offer high performance and portability. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ventricular interaction quantified with a novel multi‐scale cardiovascular model
Authors: Kerckhoffs Roy , Neal Maxwell , Bassinghtwaighte James , Omens Jeffrey , McCulloch Andrew
Published: May 2009

Ventricular interaction (VI) in the heart is the influence of function of one ventricle on the other. To investigate VI, a novel multi‐scale model of the canine cardiovascular system was developed. Multiple beats of a normal heart were simulated, followed by pulmonary artery constriction (PAC). VI was quantified by computing ventricular co‐compliances, i.e. the volumic changes in each ventricle due to a pressure change in the other ventricle (CRL = dVR/dPL and CLR = dVL/dPR). CLR and CRL varied throughout the cardiac cycles. After PAC, diastolic values changed acutely from –5.7 to –6.5 ml/mmHg, due to an abrupt change in VI. The model is likely to be useful in investigating VI, among others, in many clinical settings. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Helmholtz equation outside an open arc in a plane with a mixed boundary condition
Authors: Kolybasova Valentina , Krutitskii Pavel
Published: May 2009

A boundary value problem for the Helmholtz equation outside an open arc in a plane is studied with mixed boundary conditions. In doing so, the Dirichlet condition is specified on one side of the open arc and the boundary condition of the third kind is specified on the other side of the open arc. We consider non‐propagative Helmholtz equation, real‐valued solutions of which satisfy maximum principle. By using the potential theory the boundary value problem is reduced to a system of singular integral equations with additional conditions. By regularization and subsequent transformations, this system is reduced to a vector Fredholm equation of the second kind and index zero. It is proved that the obtained vector Fredholm equation is uniquely solvable. Therefore the integral representation for a solution of the original boundary value problem is obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of macroscopical transient frost processes and microscopical driving forces
Authors: Kruschwitz Jens , Setzer Max J.
Published: May 2009

The artificial saturation phenomenon due to freeze‐thaw cycles is described by a multi‐phase and multiscale model (1; 2; 3) formulated within the Theory of Porous Media, (4). It represents partially saturated concrete as a mixture of 5 interacting constituents φa, namely the solid skeleton φs, the bulk water φl, the pore volume occupied by vapour φv, the ice φi and the gel water phase φp. Most relevant for the model is the distinction between two length scales and their characteristic time scales. The boundary is marked where macroscopic bulk conditions change to surface physics and chemistry. Surface physics and chemistry acting on the nano‐scale affect fundamental properties of concrete and consequently the durability of concrete against freeze‐thaw.

At the macroscopic scale the model describes transient conditions (i.e. water‐uptake, heat transport, volume dilatation of 9 %, phase change of first order considering hysteresis) which are characterized by a relatively long time period to reach equilibrium in contrast to the processes modelled on the microstructure. At the microscopic scale the model represents the nanoscopic CSH‐gel system consisting of solid CSH and water as a linked system of both components basing on the concept of the “Solid‐Liquid Gel System” (5). In the constribution the numerical results of the model are presented with focus on the evaluation of the process zone during the penetration of the melting front into the matrix. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of the web‐tool on differential equations
Authors: Miidla Peep
Published: May 2009

In this presentation the web‐tool on differential equations is introduced. The structure of this and the Instructional System Design ADDIE are under consideration. The tool is in the developing stage and would be used in ECMI educational system, particularly in the Master Program of ECMI. The part of the tool in great importance are the simulation and modelling means. Creating of these leads to the collaboration with other ECMI universities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some geometric properties of a Banach sequence space n (ϕ) related to lp
Authors: Mursaleen M.
Published: May 2009

In this paper we study some geometric properties of the sequence spaces n (ϕ) such as Banach‐Saks property, fixed point property and Schur property. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Secant method under generalized Lipschitz conditions for the divided difference operator
Authors: Shakhno Stepan
Published: May 2009

In this work we introduce for the first time the generalized Lipschitz conditions for the divided difference operator. A positive integrable function, partial case of which is usual Lipschitz constant, is suggested. Under the given conditions the convergence of the Secant method for solving the operator equations in Banach spaces is investigated, the uniqueness ball for the solution is obtained. As a partial case the known results for the Lipschitz constants are received. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Usage scenarios of a semantic‐based digital shape workbench
Authors: Vavalis Manolis
Published: May 2009

Motivated by the undisputed emergence of 3D content, this paper presents cases where semantic technologies have the potential to be used to build robust real‐life solutions out of the AIM@SHAPE Digital Shape Workbench both in its current and its future forms. We focus on understanding what makes semantic knowledge applications successful in operational environments which involve shapes and present existing and future scenarios on favoring ontology based integration that systematically resolves both syntactic and semantic heterogeneity, allowing scientists to concentrate more on their content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of direct melt compounding and masterbatch dilution on the structure and properties of nanoclay‐filled polyolefins
Authors: Eteläaho Pirkko , Nevalainen Katja , Suihkonen Reija , Vuorinen Jyrki , Hanhi Kalle , Järvelä Pentti
Published: May 2009

The differences that direct melt compounding and masterbatch dilution cause in the properties of melt compounded polypropylene (PP) and high density polyethylene‐based (PE‐HD) nanocomposites are presented. The results include comparison of properties and morphology of directly melt processed organoclay nanocomposites with similar compounds diluted from commercial and in‐house‐made masterbatches to clay concentrations of 1, 3, 6, and 8 wt%. The compounds were prepared with a co‐rotating Brabender twin‐screw extruder. The degree of exfoliation and the dispersion of the nanoclay were verified with transmission electron microscopy and X‐ray diffraction. Thermal stability of the materials was examined with thermogravimetric analysis and the mechanical properties of the compounded materials were also determined. The most promising results regarding mechanical behavior were achieved with the in‐house‐made masterbatch in the form of a notable increase in Young's modulus in both matrices. There was also a distinct increase in impact strength when masterbatch was used. Changes were more pronounced in case of PP. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Unified production of chlorinated isotactic polypropylene and chlorinated paraffin via a solvent free chlorination process
Authors: Tan Kui‐Long , Li Chun‐Xi , Lu Ying‐Zhou , Wang Zi‐Hao
Published: May 2009

An environmentally friendly method for producing chlorinated isotactic polypropylene (CIPP) with chlorine percentage of 28–35, by weight is proposed, in which a reactive solvent, paraffin, is used to replace the commonly used inert solvent of carbon tetrachloride (CTC), an ozone depleting substance being phased out under the Montreal Protocol. This method utilizes the principle that paraffin can dissolve isotactic polypropylene (IPP) at about 150°C and the resulting solution can be chlorinated concurrently, forming two useful products, viz. chlorinated paraffin (CP) and CIPP, which are mutually soluble even at lower temperature, e.g., 70°C. The present method is superior to the conventional CTC solvent method because it can reduce the solvent emission dramatically, enhance the volume efficiency of reactor, and achieve a unified production of CIPP and CP under atmospheric pressure. The structure and properties of CIPP produced by two different methods are determined by differential scanning calorimetry, attenuated total reflectance‐Fourier transform infrared spectroscopy, proton magnetic resonance (1H‐NMR), and13C‐NMR. The results indicate that IPP chain can be homogeneously chlorinated in paraffin as in CTC solvent via a radical mechanism. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
G‐protein‐coupled receptor structures were not built in a day
Authors: Blois Tracy M. , Bowie James U.
Published: May 2009

Among the most exciting recent developments in structural biology is the structure determination of G‐protein‐coupled receptors (GPCRs), which comprise the largest class of membrane proteins in mammalian cells and have enormous importance for disease and drug development. The GPCR structures are perhaps the most visible examples of a nascent revolution in membrane protein structure determination. Like other major milestones in science, however, such as the sequencing of the human genome, these achievements were built on a hidden foundation of technological developments. Here, we describe some of the methods that are fueling the membrane protein structure revolution and have enabled the determination of the current GPCR structures, along with new techniques that may lead to future structures.
Xamiol: betamethasone plus calcipotriol for scalp psoriasis
Authors: Chaplin Steve , Bewley Anthony
Published: May 2009

Xamiol, a new treatment for scalp psoriasis, is a formulation of betamethasone and calcipotriol in a gel vehicle. In this New products review Steve Chaplin discusses the clinical data relating to its efficacy and adverse effects and Dr Anthony Bewley comments on its place in the treatment of scalp psoriasis. Copyright © 2009 Wiley Interface Ltd
Effect of concentration of hexamethylene tetramine on the structural morphology and optical properties of ZnO microrods grown by low‐temperature solution approach
Authors: Mridha S. , Basak D.
Published: May 2009

We study the change in the structural morphology and optical properties of aqueous solution grown ZnO microrods on glass substrates with the change in the concentration of hexamethylene tetramine (HMT). The field emission scanning electron microscope images of the microrods grown for equimolar (1:1) ratio of Zn2+ salt and HMT exhibit the highest aspect ratio, 8.3, which decreases gradually, while the relative intensity of the (100) peak in the X‐ray diffractogram increases with increase in the HMT concentration. The change in the morphology from a perfect hexagonal to an oval‐shaped needle is experimentally supported by the high‐resolution transmission electron microscope results. A sharp and strong ultraviolet photoluminescence peak ensures good structural quality of the microrods for the molar ratios 1:1 and 1:3 above which the quality degrades. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gamma‐radiation effects on NaCl:Cu crystals
Authors: Cruz‐Zaragoza E. , Chernov V. , Meléndrez R. , Barboza‐Flores M.
Published: May 2009

The γ‐radiation effects on copper‐doped NaCl:Cu crystals were investigated. Single crystals exposed to gamma radiation from 0.001 kGy to 30 kGy at room temperature exhibited optical absorption bands attributed to Cu– (236 nm), Cu+ (255 nm) and F (463 nm) centers. The F and Cu absorption annealing bands were correlated to the thermoluminescence (TL) glow‐curve peak structure around 30–165 °C and 215–350 °C, respectively. The TL glow curves of samples doped with 0.04 mol% and 0.08 mol% of Cu+ ions showed a strong quenching effect for higher doping concentration. In addition, thermal bleaching of γ‐irradiated specimens confirmed the color centers and Cu‐doping participation on the TL process. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reliability issues of SiC power MOSFETs toward high junction temperature operation
Authors: Tanimoto Satoshi , Ohashi Hiromichi
Published: May 2009

There still remain a number of reliability problems to be resolved with regard to long‐term high junction temperature operation of SiC power devices because at present they simply follow Si‐based technology. In this paper, various reliability issues for power DMOS devices on 4H‐SiC operated at a junction temperature of more than 200 °C are extensively discussed in terms of five manifest problems and potential treats: (1) interlayer dielectric erosion, (2) Al spearing, (3) Ni2Si contact disappearance, (4) electrode delamination, and (5) gate time‐dependent dielectric breakdown. Preventive measures for these issues are proposed, including the use of a Ta/TaN barrier metal, a SiCH barrier dielectric, decarbonised Ni2Si and an ONO gate dielectric, and their effectiveness is experimentally verified. A viable device structure and fabrication process that successfully incorporate these measures are then presented. Finally, a storage life of more than 5380 hours at 300 °C is demonstrated for 1 × 1 mm24H‐SiC power DMOS devices incorporating selected countermeasures. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural elucidation of metabolites of ginkgolic acid in rat liver microsomes by ultra‐performance liquid chromatography/electrospray ionization tandem mass spectrometry and hydrogen/deuterium exchange
Authors: Liu Z. H. , Chen J. , Yu L. S. , Jiang H. D. , Yao T. W. , Zeng S.
Published: May 2009

Ginkgolic acids have been shown to possess allergenic as well as genotoxic and cytotoxic properties. The question arises whether the metabolism of ginkgolic acids in the liver could decrease or increase their toxicity. In this study, theinvitrometabolism of ginkgolic acid (15:1, GA), one component of ginkgo acids, was investigated as a model compound in Sprague‐Dawley rat liver microsomes. The metabolites were analyzed by ultra‐performance liquid chromatography coupled with photodiode array detector/negative‐ion electrospray ionization tandem mass spectrometry (UPLC‐PDA/ESI‐MS/MS) and hydrogen/deuterium (H/D) exchange. The result showed that the benzene ring remained unchanged and the oxidations occurred at the side alkyl chain in rat liver microsomes. At least eight metabolites were found. Among them, six phase I metabolites were tentatively identified. This study might be useful for the investigation of toxicological mechanism of ginkgolic acids. Copyright © 2009 John Wiley & Sons, Ltd.
Sequence and phosphorylation level determination of two donkey β‐caseins by mass spectrometry
Authors: Cunsolo Vincenzo , Cairone Elisa , Saletti Rosaria , Muccilli Vera , Foti Salvatore
Published: May 2009

Two coeluting components, with experimentally measured Mr values of 25529 and 24606 Da, were identified by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and mass spectrometric analysis in the dephosphorylated casein fraction of a milk sample collected from an individual donkey belonging to the Ragusano breed of the east of Sicily. By coupling enzymatic digestions, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and RP‐HPLC/nano‐electrospray ionization tandem mass spectrometry (nESI‐MS/MS) analysis, the two proteins were identified as donkey β‐CNs and their sequences characterized completely, using the two known β‐CNs from mare as references. The two donkey β‐CNs, showing a mass difference of 923 Da, differ by the presence of the domain E27SITHINK34 in the full‐length component (Mr 25529 Da). In comparison with the mare's β‐CNs used as reference, they present nine amino acid substitutions: L→S37, R→H52, S→N81, P→V84, L→V91, R→Q203, P→L/I206, L→F210 and A→P219. Together, these substitutions account for the increase of 18 Da in the Mr of the donkey β‐CNs with respect to the counterparts from the mare. The molecular mass determination by ESI‐MS for the phosphorylated proteins showed that the full‐length component was composed of highly multi‐phosphorylated isoforms with five to seven phosphate groups. By analogy with the homologous mare's β‐CNs, the full‐length (226 amino acids) β‐CN was termed variant A, whereas the shorter (218 amino acids) β‐CN was termed variant AΔ5. Copyright © 2009 John Wiley & Sons, Ltd.
Mixtures of prior distributions for predictive Bayesian sample size calculations in clinical trials
Authors: Brutti Pierpaolo , De Santis Fulvio , Gubbiotti Stefania
Published: May 2009

In this paper we propose a predictive Bayesian approach to sample size determination (SSD) and re‐estimation in clinical trials, in the presence of multiple sources of prior information. The method we suggest is based on the use of mixtures of prior distributions for the unknown quantity of interest, typically a treatment effect or an effects‐difference. Methodologies are developed using normal models with mixtures of conjugate priors. In particular we extend the SSD analysis of Gajewski and Mayo (Statist. Med. 2006; 25:2554–2566) and the sample size re‐estimation technique of Wang (Biometrical J. 2006; 48(5):1–13). Copyright © 2009 John Wiley & Sons, Ltd.