bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and spectral studies of Cu(II), Ni(II), Co(II), Mn(II), Zn(II) and Cd(II) complexes of a new macroacyclic ligand n,n’-bis(2-benzothiazolyl)-2,6-pyridinedicarboxamide
Authors: Gudasi Kalagouda , Patil Siddappa , Vadavi Ramesh , Shenoy Rashmi , Patil Manjula
Published: October 2006

A new macroacyclic amide ligand N,N?-bis(2-benzothiazolyl)-2,6-pyridinedicarboxamide (BPD), formed by the condensation of 2,6-pyridinedicarbonyldichloride with 2-aminobenzothiazole and its Cu(II), Ni(II), Co(II), Mn(II), Zn(II) and Cd(II) complexes were synthesized. Their structures were elucidated on the basis of elemental analyses, conductance measurements, magnetic moments, spectral (IR, NMR UV-Visible, EPR and FAB) and thermal studies. The complexes exhibit an octahedral geometry around the metal center. Conductance data of the complexes suggested them to be 1:1 electrolytes. The pentadentate behavior of the ligand was proposed on the basis of spectral studies. The X-band EPR spectra of the Cu(II) and Mn(II) complexes in the polycrystalline state at room (300 K) and liquid nitrogen temperature (77 K) were recorded and their salient features are reported.
Reconciling Multiple Researcher Positionalities and Languages in International Research
Authors: Srivastava Prachi
Published: October 2006

Through the development of a set of ideas combining Merton's conceptions of the ‘Insider and Outsider’ with Lacan's notions of identity construction, the article examines: (1) the role of multiple researcher identities and positionalities, and (2) working in more than one language during data collection and analysis. The article aims to fill a surprising gap in existing literature on such issues in international educational research. Through a reflexive exercise on the fieldwork and data analysis process in one study, the article puts forward the concept of ‘currencies’ as a way to mediate researcher positionality and achieve temporary shared positionalities with research participants. It also highlights the need to mediate different languages during data analysis and presentation, introducing the concept of ‘analytic languages’ as a potentially useful construct in doing so.
Theorizing Educational Transfer: Toward a Conceptual Map of the Context of Cross-National Attraction
Authors: Rappleye Jeremy
Published: October 2006

This article highlights some of the current methodological issues surrounding how to analyze and understand educational transfer with particular reference to cross-national attraction. It reviews the resurgent interest in the themes of attraction and transfer and evaluates new models and typologies that describe those complex processes. It argues that gaps in the current research and new challenges posed by ‘globalization’ necessitate a new interpretive framework. To that end, a contextual map of cross-national attraction is presented and its component parts are described in considerable detail. Examples from the author's previous work on Chinese and American attraction to Japanese education are used to illustrate the uses of this new analytical framework. The article concludes by suggesting the various ways the device may assist in analyzing attraction and transfer and in opening up new areas of research.
Unequal Educational Outcomes among First-Generation Immigrants: The Case of Youth from the Former Soviet Union in Israel
Authors: Bodovski Katerina , Benavot Aaron
Published: October 2006

This study focuses on school enrollment and patterns of track placement in the Israeli secondary education system among immigrant youth from the former Soviet Union. This unique case is discussed in the light of segmented assimilation theory and the accommodation-without-assimilation hypothesis. The findings of the study conclude that a family's previous socio-economic status is more important than its current socio-economic status in determining the educational outcomes of immigrant youth; students whose mothers possess higher educational qualifications are more likely to be enrolled in Israeli high schools and intend to complete all necessary matriculation examinations than children whose mothers have lower educational qualifications; immigrant youth with a previous record of high academic achievements in the Soviet Union had stronger matriculation intentions and were more likely to be enrolled in academic tracks; a student's proficiency in Hebrew had strong, significant effects on enrollment status, educational intentions and track placement; youth reporting negative relations with Israeli peers and frequent arguments with parents over smoking, alcohol and drugs were more likely to drop out and have lower educational intentions; and immigrant adolescents with stronger ties to Israeli peers were less likely to be enrolled in academic and professional tracks.
Protein glycosylation and renal cancer
Authors: Ferguson Roisean E. , Vasudev Naveen S. , Selby Peter J. , Banks Rosamonde E.
Published: October 2006

Glycosylation is the most complex and common posttranslational modification. The development of cancer is associated with profound alterations in cellular glycosylation. Glycosylated proteins (glycoproteins) coat all eukaryotic cells and play pivotal roles in many aspects of tumor progression, including proliferation, invasion, metastasis, and angiogenesis. Recent technological advances in glycobiology have enabled the identification of glycan structures that are associated with particular disease states, thereby facilitating the exploitation of such changes in glycan‐based diagnostics and therapeutics. This review outlines how glycosylation alters with cancer, how such changes may be targeted for diagnostic and therapeutic means, and describes what is known currently about altered glycosylation in renal cancer.
Grid technologies
Authors: O'Neal Douglas W.
Published: October 2006

Shared computing facilities have been in existence since the early days of computing and the manner of sharing has evolved during that time from time‐shared systems to networked computers sharing a user database to peer‐to‐peer networks and now to global grids of mutually accessible systems. Grid computing provides ubiquitous access to computing resources on a scale that no single organization can provide. With scale comes the more efficient utilization of resources, as organizations donate unused resources with the knowledge that necessary resources will be available when they need capacity past what they can provide. The definition of a computer grid, much less its implementation, is still nebulous, but standards are being put into place to provide the structure necessary to provide transparent access to seemingly unlimited resources.
Congenital amegakaryocytic thrombocytopenia—Report of a new c‐mpl gene missense mutation
Authors: Passos‐Coelho J.L. , Sebastião M. , Gameiro P. , Reichert A. , Vieira L. , Ferreira I. , Miranda N. , Guimarães A. , Leal‐da‐Costa F. , Abecasis M.M.
Published: October 2006

A 44‐month old girl with congenital amegakaryocytic thrombocytopenia, already with pancytopenia, underwent an unrelated allogeneic cord blood transplantation with recovery of normal blood cell counts. The patient was a compound heterozygote for two c‐mpl missense mutations inherited from both parents, one of them, a G578A exon 4 mutation leading to a cysteine to tyrosine replacement of codon 193, previously unreported. Am. J. Hematol., 2007. © 2006 Wiley‐Liss, Inc.
No association between ADRA2A polymorphisms and schizophrenia
Authors: Clark D.A. , Mata I. , Kerwin R.W. , Munro J. , Arranz M.J.
Published: October 2006

There is evidence to suggest that the α2A‐adrenergic receptor may be involved in schizophrenia. With attention directed at the upstream regulatory region of the gene which codes for this receptor (ADRA2A), we proposed that single nucleotide polymorphisms (SNPs) within this region influences susceptibility to schizophrenia by altering the expression of this receptor. We opted to test for an influence on susceptibility by association study using 112 schizophrenic/schizoaffective disorder patients and 159 controls. The region of interest was screened for SNPs using a combination of bioinformatic searches and sequencing. A total of nine SNPs were discovered, of which four (−5972‐G/A, −2211‐A/T, −1291‐C/G and −261‐G/A) were genotyped in the entire clinical sample. No associations were evident, suggesting no influence for these SNPs in susceptibility to schizophrenia. © 2006 Wiley‐Liss, Inc.
Selenolthiol and Dithiol C‐Terminal Tetrapeptide Motifs for One‐Step Purification and Labeling of Recombinant Proteins Produced in E. coli
Authors: Cheng Qing , Johansson Linda , Thorell Jan‐Olov , Fredriksson Anna , Samén Erik , Stone‐Elander Sharon , Arnér Elias S. J.
Published: October 2006

We have previously shown that a redox‐active selenocysteine‐containing tetrapeptide—Sel‐tag (Gly‐Cys‐Sec‐Gly)—can be used as a C‐terminal fusion motif for recombinant proteins produced in Escherichia coli. This Sel‐tag allows selenolate‐targeted one‐step purification, as well as fluorescent labeling or radiolabeling either with gamma emitters (75Se) or with positron‐emitting radionuclides (11C). Here we have analyzed four different redox‐active C‐terminal motifs, carrying either dithiol (Gly‐Cys‐Cys‐Gly or Ser‐Cys‐Cys‐Ser) or selenolthiol (Gly‐Cys‐Sec‐Gly or Ser‐Cys‐Sec‐Ser) motifs. Utilizing these different functional motifs with the same recombinant protein (Fel d 1), we were able to assess their relative reactivities and potential usefulness for biotechnological applications. We found that all four redox‐active tags could be utilized for efficient one‐step purification to provide pure protein from a crude bacterial lysate through reversible binding to phenylarsine oxide sepharose, with yields and purities comparable to those obtained for a His‐tagged protein purified by the more common approach with use of a Ni2+ column. For labeling with electrophilic fluorescent or radioactive compounds, however, the selenolthiol motifs were considerably more efficient than their dithiol counterparts. The results thus show that both the selenolthiol‐ and the dithiol‐containing tags can serve as efficient alternatives to His‐tags for protein purification, while the selenolthiol motifs offer additional and unique potential for Sec‐targeted labeling. It should therefore be possible to utilize these multifunctional tetrapeptide motifs to develop a wide range of novel biotechnological applications based on Sec targeting with electrophilic compounds.
Component‐based iterative methods for sparse linear systems
Authors: Jones J. , Sosonkina M. , Saad Y.
Published: October 2006

Iterative methods play an important role in solving large‐scale systems of linear equations that arise in real‐world applications. Due to numerous linear system properties that may affect the solution, it is rather difficult for a user to develop a good sparse linear system solver from scratch. Thus, various collections of solution methods are made available to the user. One such software package is SPARSKIT, which is well known in the scientific community. Written in FORTRAN77 and provided with a cumbersome interface, it is considered, however, a legacy code. Our objective is to enable its wider usage in modern applications and to facilitate further SPARSKIT enhancements. Applying a ‘peer‐component’ design, we have created a set of SPARSKIT components that: (a) incorporate both original and new iterative methods; (b) are readily extensible with more methods; (c) may be connected to applications in a component framework; and (d) provide access from a variety of programming languages. Tools available from the Common Component Architecture (CCA) Forum enabled our component design of SPARSKIT. Copyright © 2006 John Wiley & Sons, Ltd.
High‐speed network and Grid computing for high‐end computation: application in geodynamics ensemble simulations
Authors: Zhou S. , Kuang W. , Jiang W. , Gary P. , Palencia J. , Gardner G.
Published: October 2006

High‐speed network and Grid computing have been actively investigated, and their capabilities are being demonstrated. However, their application to high‐end scientific computing and modeling is still to be explored. In this paper we discuss the related issues and present our prototype work on applying XCAT3 framework technology to geomagnetic data assimilation development with distributed computers, connected through an up to 10 Gigabit Ethernet network. Copyright © 2006 John Wiley & Sons, Ltd.
Component‐oriented application construction for a Web service‐based Grid
Authors: Schmidt Rainer , Benkner Siegfried , Brandic Ivona , Engelbrecht Gerhard
Published: October 2006

We present the architecture and prototype implementation of a component‐oriented programming environment for a Web service based computational Grid. As middleware, we utilize the Vienna Grid Environment (VGE), a framework that enables the provision of compute‐intensive parallel applications as configurable, QoS‐aware Grid services. Our component model follows the Common Component Architecture (CCA) and models application Web services as distributed components. We describe a component framework that integrates VGE services with a component model allowing to express and dynamically manage application and performance meta‐data as well as dependencies on the infrastructure or other components. Furthermore, we show how the client programming interface is used to compose Grid applications from abstract application components that are mapped against available Grid services by the component framework at runtime. Copyright © 2006 John Wiley & Sons, Ltd.
Design and implementation issues for distributed CCA framework interoperability
Authors: Govindaraju Madhusudhan , Lewis Michael J. , Chiu Kenneth
Published: October 2006

Component frameworks, including those that support the Common Component Architecture (CCA), represent a promising approach to addressing the challenge of building and deploying high‐performance scientific applications in Grid environments, one that is being realized, for example, in our LegionCCA and XCAT‐C++ frameworks. The next step beyond building independent individual frameworks is making them interoperate. Component‐based applications should be able to transparently span multiple disjoint component frameworks with low overhead as compared with the same applications running within a single framework. Interoperable frameworks enable applications to take advantage of more resources, and to better match constituent parts to the underlying resources that best support them. The CCA specification does not prescribe a wire format for inter‐component calls in distributed frameworks, thereby promoting considerable flexibility and customization for the framework developer. This approach thus requires an additional specific strategy outside of the CCA to support interoperability between distributed frameworks. Mandating one common wire format, however, risks choosing the wrong format. We discuss in detail five underlying component framework interoperability requirements, and three general approaches to addressing them. We then discuss how the approaches can be applied to meet the requirements, and address the advantages, issues, and implications of doing so. This effectively defines a design space for framework interoperability approaches. We then address the communication interoperability in detail via a single multi‐protocol communication library called Proteus, and discuss how we have incorporated it into two distinct distributed framework implementations of the CCA specification: LegionCCA and XCAT‐C++. Copyright © 2006 John Wiley & Sons, Ltd.
Cross‐organization interoperability experiments of weather and climate models with the Earth System Modeling Framework
Authors: Zhou Shujia , Balaji V. , Cruz Carlos , da Silva Arlindo , Hill Chris , Kluzek Erik , Smithline Shep , Trayanov Atanas , Yang Weiyu
Published: October 2006

Typical weather and climate models need a software tool to couple sub‐scale model components. The high‐performance computing requirements and a variety of model interfaces make the development of such a coupling tool very challenging. In this paper, we describe the approach of the Earth System Modeling Framework, in particular its component and coupling mechanism, and present the results of three cross‐organization model interoperability experiments. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis, Characterization, and Crystal Structure of Two Manganese Metallacrowns: 30‐Metallacrown‐10 and 18‐Metallacrown‐6 with Ligands Derived from 3‐Hydroxy‐2‐naphthalenecarbohydrazide
Authors: Dou Jianmin , Liu Mingli , Li Dacheng , Wang Daqi
Published: October 2006

Two manganese metallacrowns [Mn10(pnhz)10(DMF)4(H2O)6]·10.5H2O·MeOH·DMF (1) and [Mn6(anhz)6(DMF)2(H2O)4]·6DMF (2), (H3pnhz = 3‐hydroxy‐N‐phenyl‐2‐naphthalenecarbohydrazide, H3anhz = N‐acyl‐3‐hydroxy‐2‐naphthalenecarbohydrazide) have been prepared by the reactions of two pentadentate ligands, H3anhz and H3pnhz, with the corresponding manganese(II) salt, respectively, and characterized by elemental analysis, IR spectra, and X‐ray single‐crystal diffraction analysis. Complex 1 has an [Mn–N–N]10 skeleton with two kinds of MnIII centers in an ···AABAB··· alignment, and the metallic centers exhibit a ···ΔΛΔΛ··· chiral configuration alignment. Adjacent molecules are linked by four intermolecular H bonds to form a 1D infinite chain structure. This is the first 1D supramolecular sample of a metallacrown formed by weak interactions. Complex 2 shows an [Mn–N–N]6 skeleton with two kinds of MnIII centers in a ···BAA··· alignment. The successive manganese centers possess a ···ΔΛΔΛ··· chiral configuration alignment. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Intramolecular Apical C–H···M Interactions in Square‐Planar Nickel(II) Complexes with Dianionic Tridentate Ligands and 2‐Phenylimidazole
Authors: Mukhopadhyay Abhik , Pal Samudranil
Published: October 2006

Two square‐planar ternary nickel(II) complexes [Ni(bhac)(phim)] (1) and [Ni(ahac)(phim)] (2) with O,N,O‐donor Schiff bases [acetylacetone benzoylhydrazone (H2bhac) and acetylacetone acetylhydrazone (H2ahac)] and sp2N‐donor 2‐phenylimidazole (phim) as the ancillary ligand have been synthesised and characterised by analytical, spectroscopic, magnetic and electrochemical methods. The solid‐state structures of both complexes have been determined by X‐ray crystallography. The asymmetric unit of1contains a single complex molecule while that of2contains four complex molecules with different conformations. The molecular structures of both complexes reveal that one of the twoorthoC–H groups of the pendant phenyl ring of the phim ligand is very close to the metal centre at the apical site indicating the presence of an intramolecular C–H···Ni interaction. In the structures of1and2, the shape of the C–H···Ni interaction is determined by the twisting of the phim ligand and the extent of orthogonality between the planes containing the chelate rings formed by the tridentate ligand and the imidazole ring. A survey of the reported X‐ray structures of similar d8metal ion complexes containing intramolecular C–H···M interactions has been performed for comparison with the structural features of1and2. The optimised molecular structures of1and2generated by calculations based on the density functional method are compared with the experimental structures. Calculations also reveal that the four molecules present in the asymmetric unit of2are very close in energy. Theoretical studies and the down‐field shift of the proton resonance on cooling in the NMR spectra suggest three‐centre four‐electron hydrogen‐bond character of the observed apical C–H···Ni interaction in1and2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A high‐order accurate method for two‐dimensional incompressible viscous flows
Authors: De Arnab Kumar , Eswaran Vinayak
Published: October 2006

A high‐order accurate solution method for complex geometries is developed for two‐dimensional flows using the stream function–vorticity formulation. High‐order accurate spectrally optimized compact schemes along with appropriate boundary schemes are used for spatial discretization while a two‐level backward Euler implicit scheme is used for the time integration. The linear system of equations for stream function and vorticity are solved by an inner iteration while contravariant velocities constitute outer iterations. The effect of curvilinear grids on the solution accuracy is studied. The method is used to compute Cartesian and inclined driven cavity, flow in a triangular cavity and viscous flow in constricted channel. Benchmark‐like accuracy is obtained in all the problems with fewer grid points compared to reported studies. Copyright © 2006 John Wiley & Sons, Ltd.
A hybrid immersed‐boundary and multi‐block lattice Boltzmann method for simulating fluid and moving‐boundaries interactions
Authors: Sui Yi , Chew Yong‐Tian , Roy Partha , Low Hong‐Tong
Published: October 2006

A numerical method is developed for modelling the interactions between incompressible viscous fluid and moving boundaries. The principle of this method is introducing the immersed‐boundary concept in the framework of the lattice Boltzmann method, and improving the accuracy and efficiency of the simulation by refining the mesh near moving boundaries. Besides elastic boundary with a constitutive law, the method can also efficiently simulate solid moving‐boundary interacting with fluid by employing the direct forcing technique. The method is validated by the simulations of flow past a circular cylinder, two cylinders moving with respect to each other and flow around a hovering wing. The versatility of the method is demonstrated by the numerical studies including elastic filament flapping in the wake of a cylinder and fish‐like bodies swimming in quiescent fluid. Copyright © 2006 John Wiley & Sons, Ltd.
Microrough titanium surface affects biologic response in MG63 osteoblast‐like cells
Authors: Kim Myung‐Joo , Kim Chang‐Whe , Lim Young‐Jun , Heo Seong‐Joo
Published: October 2006

The purpose of this study was to define the surface properties of prepared titanium (Ti) disks, which served as a model system, and to contrast the biologic response of MG63 cells exposed to Ti disks with different levels of surface roughness. The surface properties interact with each other, resulting in a change of other surface qualities in addition to roughness due to the surface roughening procedure. The machined Ti disks were roughened by sandblasting and electric glow discharging. The surface properties of the Ti specimens were inspected through a comprehensive surface analysis. MG63 cell behaviors were compared along with cell number, alkaline phosphatase (ALP) activity, Runx2 gene expression, and type I collagen production. Statistics were evaluated, using analysis of variance (ANOVA). The sandblasted Ti disks demonstrated well‐controlled surface roughness features and meaningful average roughness ranges, including the surface roughness of the “modern” microrough implant, used clinically. With increasing Ti surface roughness, the cell number decreased, while the ALP activity, type I collagen production, and Runx2 gene expression increased significantly. The rougher the Ti surface was, the sooner the Runx2 gene was expressed. Based on these results, we suggest that the microrough Ti surfaces of the 1–3 μm range may contribute effectively to osteogenic differentiation and proliferation in MG63 cells. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Effect of oxygen inhibition on composite repair strength over time
Authors: Dall'Oca Susanna , Papacchini Federica , Goracci Cecilia , Cury Álvaro H. , Suh Byoung I. , Tay Franklin R. , Polimeni Antonella , Ferrari Marco
Published: October 2006

The study was aimed at examining whether an oxygen inhibition layer is required for bonding a repairing to a pre‐existing composite, and to determine the time required for free radicals within a composite substrate to decay to the extent that the composite repair strength drops significantly. Ten slabs of Gradia Direct Anterior (GC Corp.) were divided into (1) control group: an interfacial oxygen inhibition layer was created by applying and light‐curing two layers of bonding resin (D/E Resin, Bisco) to the slabs surface in atmospheric air; (2) experimental group: the absence of an interfacial oxygen inhibition layer was obtained by light‐curing the second bonding resin layer in a nitrogen atmosphere. After 1 and 2 h, 1, 14, and 30 days of air storage, a composite repair was layered over the bonding resin. Microtensile bond strengths were measured and statistically analyzed. The curing atmosphere was not a significant factor for bond strength (p = 0.82), and time and curing atmosphere‐time interaction were significant (p < 0.001). The 30 day‐strengths were the lowest (p < 0.05). An oxygen‐inhibited layer is not initially required for bonding to resin composite, and it takes more than 14 days before the bond strength between a pre‐existing and a fresh composite drops. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
CO2 laser‐induced zonation in dental enamel: A Raman and IR microspectroscopic study
Authors: Klocke Arndt , Mihailova Boriana , Zhang Shengqiang , Gasharova Biliana , Stosch Rainer , Güttler Bernd , Kahl‐Nieke Bärbel , Henriot Peter , Ritschel Bodo , Bismayer Ulrich
Published: October 2006

The gradient of structural alteration and molecular exchange across CO2 laser‐irradiated areas in dental enamel was analyzed by Raman and attenuated total reflectance infrared microspectroscopy. The type and the degree of structural changes in morphologically distinguishable zones within the laser spot vary depending on the laser‐irradiation parameters—power (1 and 3 W), treatment time (5 and 10 s), and operational mode (super pulse and continuous wave). Using higher power, irrespective of the operation mode, the enamel tissue ablates and a crater is formed. The prevalent phase at the bottom of the crater is dehydrated O‐bearing apatite, that is, the fundamental framework topology is preserved. Additional nonapatite calcium phosphate phases are located mainly at the slope of the laser crater. No structural transformation of mineral component was detected aside the crater rim, only a CO3–CO2 exchange, which decays with the radial distance. A lower‐power laser irradiation slightly roughens the enamel surface and the structural modification of enamel apatite is considerably weaker for continuous wave than for super pulse mode. Prolonged low‐power laser treatment results in recrystallization, and thus structural recovering of apatite might be of clinical relevance for enamel surface treatments. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Environmental degradation of glass‐ionomer cements: A depth‐sensing microindentation study
Authors: Wang X. Y. , Yap Adrian U. J. , Ngo H. C. , Chung S. M.
Published: October 2006

This study investigated the effects of various environmental conditions on the hardness and elastic modulus of restorative glass‐ionomer cements (GICs). Two resin‐modified GICs (RMGICs) (Fuji II LC [FL]; Photac‐Fil Quick [PQ]) and three highly viscous GICs (HVGICs) (Fuji IX Fast [FN]; KetacMolar [KM]; KetacMolar Quick [KQ]) were evaluated in this study. Specimens were fabricated according to the manufacturers' instructions and stored under a variety of conditions (n = 7): 100% humidity, distilled water, pH 5 demineralization solution, and pH 7 remineralization solution. The hardness and elastic modulus were measured using a depth‐sensing microindentation test after 4 weeks. The results were analyzed using the independent samples T‐test and ANOVA/Scheffe's post hoc test (p < 0.05). HVGICs showed significantly higher hardness and elastic modulus than RMGICs under all storage conditions. Storage in distilled water significantly increased the hardness and elastic modulus of FN, but decreased that of PQ. All HVGICs and RMGICs stored in remineralization solution had hardness values and elastic moduli comparable to those stored in water. Compared to remineralization solution, demineralization solution had no significant effects on the modified GICs with the exception of KQ. The results suggest that the mechanical properties of glass‐ionomer restoratives are material‐type and storage condition dependent. Therefore, the clinical selection of a glass‐ionomer material should be based on the oral environment to which it will be subjected. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Computer assisted Koeppen climate classification: a case study for Brazil
Authors: Sparovek Gerd , De Jong Van Lier Quirijn , Dourado Neto Durval
Published: October 2006

Koeppen's climate classification, developed one century ago, is still used as a reference for large‐scale climate mapping and useful for climatologic research (climate shift, climate model testing, and ecological research). This paper describes a software that was developed to allow non‐assisted Koeppen climate classification based on a simple database (monthly mean temperatures and rainfall) as input. The software follows, as strictly as possible, the original concepts suggested by Koeppen, but does not include climates that cannot be defined by simple input parameters. Combined with GIS tools, the software was used to produce the first comprehensive climate map of Brazil using a large database. The map showed 21 Climate Equations in three climate zones (A = tropical moist; B = dry; C = moist with mild winter). This map was compared with an existing climate map of Brazil (FAO/SDRN). The two maps showed good agreement only in the less detailed information (climate zone and type). The complete Climate Equations were not comparable in relation to spatial distribution and class coincidence. Improvements were made for Koeppen's climate classification, avoiding computational or database errors, and it increased the details for climate classification of Brazil. Copyright © 2006 Royal Meteorological Society
Trends in snow ablation over North America
Authors: Dyer Jamie L. , Mote Thomas L.
Published: October 2006

A substantial decrease in snow cover extent (SCE) and snow depth over North America has been observed over the 1960–2000 period. One explanation for the changes in North American snow cover is a change in the frequency and/or intensity of snow ablation. This study uses a gridded dataset of United States and Canadian surface observations from 1960 to 2000 to examine patterns of snow ablation over North America. An ablation event is defined as an interdiurnal snow depth change exceeding a critical value. Results show a significant positive trend in the frequency of ablation events during March (p < 0.05) and a significant negative trend in May (p < 0.05), indicating an earlier onset of ablation. This pattern is consistent for ablation of varying intensity. Surface energy budget components and air mass frequencies are examined in relation to the observed trends in snow ablation. Changes in March ablation frequency were shown to be dominated by increases in the sensible heat flux. A higher frequency of dry moderate instead of moist polar air masses during high ablation years may explain the increase in sensible heat flux and ablation over the study period. Copyright © 2006 Royal Meteorological Society
Timing of radiation in children with medulloblastoma/PNET
Authors: Santos Marcos A. , Viégas Célia M.P. , Servidoni Renata A. , Barros Mario H.M. , Pinel Maria Isabel , Araújo Carlos M.M.
Published: October 2006

Background

To evaluate the importance of timing of radiation therapy in children with PNET/medulloblastoma, treated at the Brazilian National Cancer Institute (INCA).

Procedure

The records of 101 children with confirmed diagnosis of medulloblastoma were retrospectively reviewed. Patients had a median follow‐up of 48 months (0.5–241 months). The age varied from 0.8 to 17.5 years (median: 7.6 years) and 21.7% were 3 years old or younger.

Results

According to the data collected from patients that received treatment for medulloblastoma from 1983 to 2001, the overall survival (OS) rate was 53% and the Disease Free Survival (DFS) rate was 40%. Multivariate analysis showed that under age 3 years, presence of neoplasic cells in the cerebrospinal fluid (CSF) at presentation or subtotal tumor resection resulted in a worse OS. The patients that received a biological effective dose (BED) greater than 44 Gy10 had better prognosis. Two‐thirds of the patients had complete response after the initial treatment. Among them, 50% (34 patients) recurred, and of those 34 patients, 42% of them (14 patients) had recurrence in the posterior fossa.

Conclusion

Surgery with total resection of the tumor and absence of neoplasic cells in the CSF are effective predictors of better OS. Radiotherapy was more effective when a BED was greater than 44 Gy10. Pediatr Blood Cancer © 2006 Wiley‐Liss, Inc.
Dynamics and assembly of the cytolethal distending toxin
Authors: Hu Xin , Stebbins C. Erec
Published: October 2006

The cytolethal distending toxin (CDT) is a widespread bacterial toxin that consists of an active subunit CdtB with nuclease activity and two ricin‐like lectin domains, CdtA and CdtC, that are involved in the delivery of CdtB into the host cell. The three subunits form a tripartite complex that is required to achieve the fully active holotoxin. In the present study we investigate the assembly and dynamic properties of the CDT holotoxin using molecular dynamics simulations and binding free energy calculations. The results have revealed that CdtB likely adopts a different conformation in the unbound state with a closed DNA binding site. The two characterized structural elements of the aromatic patch and groove on the CdtA and CdtC protein surfaces exhibit high mobility, and free energy calculations show that the heterodimeric complex CdtA‐CdtC, as well as the CdtA‐CdtB and CdtB‐CdtC sub‐complexes are less energetically stable as compared to the binding in the tripartite complex. Analysis of the dynamical cross‐correlation map reveals information on the correlated motions and long‐range interplay among the CDT subunits associated with complex formation. Finally, the estimated binding free energies of subunit interactions are presented, together with the free energy decomposition to determine the contributions of residues for both binding partners, providing insight into the protein–protein interactions in the CDT holotoxin. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Bombesin analogs containing α‐amino‐isobutyric acid with potent anticancer activity
Authors: Prasad Sudhanand , Mathur Archna , Gupta Neena , Jaggi Manu , Singh Anu T. , Rajendran Praveen , Sanna Vinod K. , Datta Kakali , Mukherjee Rama
Published: October 2006

Six octapeptide bombesin (BN) analogs were synthesized by substituting α‐aminoisobutyric acid (Aib), in place of Ala9 or Gly11, or both, in the [D‐Phe6, desMet14]‐BN (6–14) sequence: D‐Phe6‐Gln7‐Trp8‐Ala9‐Val10‐Gly11‐His12‐Leu13‐NH2 (P0). Additionally, Leu13 was replaced with isoleucine in two analogs and one of the analogs was butanoylated at the N‐terminus. The antiproliferative activity of the analogs was tested in vitro on human pancreatic (MiaPaCa‐2) and colon cancer (SW620, HT29 and PTC) cell lines using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The analogs demonstrated anticancer activity in the above cell lines at concentrations ranging from 0.01 nM to 1 µM. One of the analogs, P6, was evaluated for in vivo tumor regression in a xenograft model of human primary colon cancer in athymic nude mice and was found to cause significant reduction in tumor volume. NMR and molecular dynamics (MD) simulation studies for this analog revealed the presence of a mixed 310/α‐helical structure. This study demonstrates that the designed BN analogs retain their anticancer activity after the incorporation of the constrained amino acid, Aib, and are potential molecules for future use in cancer therapy and drug targeting. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Atomic and molecular cubature grids
Authors: Hall G. G. , Rees D.
Published: October 2006

This article presents cubature grids of the Gaussian type that are adapted for the purpose of wave function calculation on atoms and molecules. The problems of the singularity at the nucleus, the derivatives in the kinetic energy, and the presence of two‐electron integrals are shown to be resolved. Each grid has a definite degree of accuracy so that it reproduces the exact values of all the integrals in a defined class. Seventh‐degree accuracy can be obtained from a grid of 143 nodes. The grids are applied, as simple illustrations, to well‐known self‐consistent field (SCF) calculations on helium. Grids for homonuclear diatomics are also discussed and an illustrative application given to a homonuclear diatomic molecule. A comparison between a molecular grid and the union of two unmodified atomic grids shows that overlaps and distortions in weights can occur to the extent that this is not practical. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Transport layer protocols and architectures for satellite networks
Authors: Caini Carlo , Firrincieli Rosario , Marchese Mario , Cola Tomaso de , Luglio Michele , Roseti Cesare , Celandroni Nedo , Potortí Francesco
Published: October 2006

Designing efficient transmission mechanisms for advanced satellite networks is a demanding task, requiring the definition and the implementation of protocols and architectures well suited to this challenging environment. In particular, transport protocols performance over satellite networks is impaired by the characteristics of the satellite radio link, specifically by the long propagation delay and the possible presence of segment losses due to physical channel errors. The level of impact on performance depends upon the link design (type of constellation, link margin, coding and modulation) and operational conditions (link obstructions, terminal mobility, weather conditions, etc.). To address these critical aspects a number of possible solutions have been presented in the literature, ranging from limited modifications of standard protocols (e.g. TCP, transmission control protocol) to completely alternative protocol and network architectures. However, despite the great number of different proposals (or perhaps also because of it), the general framework appears quite fragmented and there is a compelling need of an integration of the research competences and efforts. This is actually the intent of the transport protocols research line within the European SatNEx (Satellite Network of Excellence) project. Stemming from the authors' work on this project, this paper aims to provide the reader with an updated overview of all the possible approaches that can be pursued to overcome the limitations of current transport protocols and architectures, when applied to satellite communications. In the paper the possible solutions are classified in the following categories: optimization of TCP interactions with lower layers, TCP enhancements, performance enhancement proxies (PEP) and delay tolerant networks (DTN). Advantages and disadvantages of the different approaches, as well as their interactions, are investigated and discussed, taking into account performance improvement, complexity, and compliance to the standard semantics. From this analysis, it emerges that DTN architectures could integrate some of the most efficient solutions from the other categories, by inserting them in a new rigorous framework. These innovative architectures therefore may represent a promising solution for solving some of the important problems posed at the transport layer by satellite networks, at least in a medium‐to‐long‐term perspective. Copyright © 2006 John Wiley & Sons, Ltd.
Writing as a problem: African grassroots writing, economies of literacy, and globalization
Authors: BLOMMAERT JAN
Published: October 2006

This article analyzes a set of handwritten documents produced by a Burundese asylum seeker in Belgium. The documents are instances of “grassroots writing”: their authorship is collective, and they display considerable problems with “remembering.” They are also rather typical text-artifacts of globalization processes, in which literacy products from one part of the world meet literacy expectations from another part. Two general points are derived from the analysis. (i) The function of documents such as these is not “reading,” but rather a complex of reading, viewing, and decoding. The documents are at least partiallyvisualbearers of information. Such functions need to be investigated ethnographically. (ii) The reason for this is the fact that the production and reception of such documents has to be set against the background of widely different economies of literacy. Consequently, the differences between text production and text reception are grounded in worldwide patterns of inequality. This casts doubt on a number of popular theses about the nature
Evaluation in media texts: A cross-cultural linguistic
investigation
Authors: CHEN LILY
Published: October 2006

A quantitative/interpretative approach to the comparative
linguistic analysis of media texts is proposed and applied to a
contrastive analysis of texts from the English-language China
Daily and the UK Times to look for evidence of
differences in what Labov calls “evaluation.” These
differences are then correlated to differences in the roles played by
the media in Britain and China in their respective societies. The aim
is to demonstrate that, despite reservations related to the Chinese
texts not being written in the journalists' native language, a
direct linguistic comparison of British media texts with Chinese media
texts written in English can yield valuable insights into the workings
of the Chinese media that supplement nonlinguistic studies.
J. K. Chambers, Peter Trudgill and Natalie Schilling-Estes
(eds.), The handbook of language variation and change.
(Blackwell Handbooks in Linguistics.) Oxford and Malden, MA: Blackwell.
2002. xii + 807 pp.
Authors: Mesthrie Rajend
Published: October 2006

This is the eleventh volume in the Blackwell series “Handbooks
in Linguistics.” Of the previous ten, one was devoted to general
sociolinguistics (Coulmas 1997), making this
the first in the series to deal with a specific branch of
sociolinguistics. For many scholars, variation theory (including the
study of change in progress) is the heartland of sociolinguistics,
though not everyone would go as far as Chambers
2003 in equating sociolinguistic theory with variation theory
alone. As the earlier Blackwell handbook suggests, the field of
sociolinguistics is broader than variation theory per se. However,
considering the richness of the handbook under review, one can
understand why variation theory should hold the high ground in
sociolinguistics. The handbook comprises 29 chapters, divided into five
sections: methodologies, linguistic structure, social factors, contact,
and language and societies.
The new geopolitics of division and the problem of a Kantian Europe
Authors: ELDEN STUART , BIALASIEWICZ LUIZA
Published: October 2006

Immanuel Kant is today often invoked as an emblematic figure for Europe. In works by thinkers such as Zygmunt Bauman, Jacques Derrida, Michel Foucault and Jürgen Habermas, among others, Kant’s work stands as a core reference for discussions of the European Modern and the legacy of the Enlightenment, even if this appropriation is not uncritical. The spectre of Kant also haunts Europe in more pedestrian understandings of the ideal. Prominent politicians such as Gerhard Schroeder, Joschka Fischer, Dominique de Villepin and Romano Prodi have all paid tribute to his influence, while in a variety of popular-academic texts Kant’s ‘cosmopolitical’ dream has been invoked as a paradigm for Europe – if not a shorthand for the European social model tout court.
History, theory and the narrative turn in IR
Authors: ROBERTS GEOFFREY
Published: October 2006

My lecture has three main themes:

First, the nature and extent of the turn to history and narrative in the study of
international relations.

Second, the contribution of narrative history to IR theory, not as an adjunct or
empirical resource, but as a theoretical perspective in its own right. Narrative
historians of international relations may not adhere to an explicit theory of international
relations but they do practice an implicit philosophy of history, a philosophy
as sophisticated and theoretically fertile as any other IR theoretical approach.
Linear and nonlinear circular dichroism of R-(+)-3-methylcyclopentanone
Authors: Li R. , Sullivan R. , Al-Basheer W. , Pagni R. M. , Compton R. N.
Published: October 2006

Linear and nonlinear circular dichroism of R-(+)-3-methylcyclopentanone (R-3MCP) is reported in the gas and liquid phases. Measurements of (2+1) resonance-enhanced multiphoton ionization circular dichroism (REMPICD) for nozzle-jet expanded molecular beams of the equatorial conformer of R-3MCP are presented. Monitoring either mass-selected cations or photoelectrons produced via (2+1) REMPI through the n→3s Rydberg transition yielded a REMPICD of +1.5±0.5% [REMPICD≡2(IL−IR)∕(IL+IR)], where IL∕R refers to the ion/electron signal for left/right circularly polarized light. A racemic mixture of 3-methylcyclopentanone showed no significant CD; however, the signal fluctuations were much larger than that observed for the resolved R-(+)-3-methylcyclopentanone as might be expected for the small number of ions produced from slightly unequal numbers of enantiomers in each laser shot. Gas phase, vibrationally resolved, one-photon CD for vapor phase R-(+)-3-methylcyclopentanone (i.e., admixture of five axial and equatorial forms) was measured to be ∼0 and −0.004 at photon energies corresponding to the one- (nonresonant) and two-(3s resonance) photon energy levels. The one-photon CD (of the room temperature population of conformers) at an energy corresponding to the ionization step was measured previously to be ∼+0.0011 which is of the same sign as the REMPICD. The first step is also near a positive CD region. This suggests that the (2+1) REMPICD is determined primarily by both the initial and continuum steps. The one-photon CDs for the equatorial and axial forms of 3MCP are calculated, using GAUSSIAN03, to be approximately equal but having opposite sign for the transitions of interest. The CD for 3MCP in cyclohexane is found to be strongly temperature dependent as a result of the presence of both the axial and equatorial conformers. The energy difference between the two conformers is determined from a van’t Hoff plot of these data to be 3.50±0.05kJ∕mole in cyclohexane and is ∼1kJ∕mole smaller than measurements employing other methods.
Expressions for the stress and elasticity tensors for angle-dependent potentials
Authors: Van Workum Kevin , Gao Guangtu , Schall J. David , Harrison Judith A.
Published: October 2006

The stress and elasticity tensors for interatomic potentials that depend explicitly on bond bending and dihedral angles are derived by taking strain derivatives of the free energy. The resulting expressions can be used in Monte Carlo and molecular dynamics simulations in the canonical and microcanonical ensembles. These expressions are particularly useful at low temperatures where it is difficult to obtain results using the fluctuation formula of Parrinello and Rahman [J. Chem. Phys. 76, 2662 (1982)]. Local elastic constants within heterogeneous and composite materials can also be calculated as a function of temperature using this method. As an example, the stress and elasticity tensors are derived for the second-generation reactive empirical bond-order potential. This potential energy function was used because it has been used extensively in computer simulations of hydrocarbon materials, including carbon nanotubes, and because it is one of the few potential energy functions that can model chemical reactions. To validate the accuracy of the derived expressions, the elastic constants for diamond and graphite and the Young’s Modulus of a (10,10) single-wall carbon nanotube are all calculated at T=0K using this potential and compared with previously published data and results obtained using other potentials.