bluuebunny/crossref_metadata_2025 huggingface dataset:
Familial, demyelinating sensory and motor polyneuropathy with conduction block
Authors: Scelsa Stephen N.
Published: November 2009

Both multifocal, demyelinating features and prednisone responsiveness are rare in Charcot–Marie–Tooth (CMT) disease. We report a mother and son with a prednisone‐responsive, multifocal, demyelinating, predominantly sensory polyneuropathy that was associated with an isoleucine92valine polymorphism of lipopolysaccharide‐induced TNF‐alpha factor (LITAF). The mother had a multifocal, acquired, demyelinating sensory and motor polyneuropathy (MADSAM)‐like presentation. The son developed left peroneal neuropathy during acute Lyme disease with a subsequent relapsing, MADSAM‐like illness, despite antibiotic treatment. Both shared prednisone responsiveness and multifocal, demyelinating features electrophysiologically. MADSAM may be familial (FaDSAM) and respond to prednisone. Muscle Nerve 41: 558–562, 2010
Construct and concurrent validation of the MG‐QOL15 in the practice setting
Authors: Burns Ted M. , Grouse C.K. , Conaway Mark R. , Sanders Donald B.
Published: November 2009

Health‐related quality of life (HRQOL) estimates can play an important role in patient care by providing information about the patient's perception of impairment and disability and the degree to which the patient tolerates disease manifestations. The 15‐item myasthenia gravis quality of life scale (MG‐QOL15) is an HRQOL evaluative instrument specific to patients with myasthenia gravis (MG) that was designed to be easy to administer and interpret. In this multicenter study we demonstrate the construct validity of the MG‐QOL15 in the practice setting. To assess the construct validity, score distributions were examined for test items in different MG patient groups that represent the clinical spectrum of the disease. For example, patients in remission more frequently scored test items as normal than did patients in other groups. Patients with lower (better) MG composite scores also more frequently scored items as normal than did patients with higher (worse) scores. There was also appropriate correlation between the MG‐QOL15 and the other MG‐specific scales studied. The study findings shed light on what troubles MG patients. The MG‐QOL15 has construct validity in the clinical practice setting and represents an efficient and valuable tool for assessing HRQOL for patients with MG. Muscle Nerve, 2010
Local government reform in South Africa: An analysis of financial management legislative compliance by municipalities
Authors: Graves Nigel , Dollery Brian
Published: November 2009

South African local government has undergone radical transformation. The reform process included a local government financial management best‐practice technical assistance programme (MFMTAP) targeting financial management and especially budget quality reform. Dollery and Graves (2009) earlier examined the efficacy of the South African National Treasury (NT's) municipal budget funding compliance technique for measuring adherence to the Municipal Finance Management Act's (MFMA) budget funding requirements using a single metropolitan municipality case study. This article further evaluates the robustness and validity of the funding compliance instrument as a reform performance measurement tool by comparing the results of four geographically and demographically different municipalities. Also introduced is a performance ‘trend’ instrument similar to a ‘Likert scale’ for comparing municipal performance. Optimal tax revenue theory is invoked to examine this key revenue variable for producing a compliant budget. The article finds the ‘budget funding’ reform component of the Best‐Practice Technical Assistance (BPTA) programme presently ineffective and unsustainable. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of the effect of mica and talc and chemical coupling on the rheology, morphology, and mechanical properties of polypropylene composites
Authors: Jahani Yousef
Published: November 2009

The effect of filler types of mica and talc on the oscillatory shear rheological properties, mechanical performance, and morphology of the chemically coupled polypropylene composites is studied in this work. The Maleic Anhydride grafted Polypropylene (MAPP) was used as an adhesion promoter for coupling mineral particles with the polypropylene matrix. The samples were prepared by a co‐rotating, L/D = 40, 25 mm twin screw extruder. The tensile tests carried out on the injection molded samples showed a reinforcing effect of talc up to 20 wt% on the Polypropylene (PP). The tensile strength of PP‐mica composites showed a slight decrease at all percentages of mica. The effect of chemical coupling by using MAPP on the tensile strength was more pronounced in increasing the tensile strength for PP‐mica than PP‐talc composites. The complex viscosity curve of pure PP and the composites, showed a Newtonian plateau (η0) up to 30 wt% at low frequency terminal zone. By increasing the filler content to 40 and 50 wt%, the complex viscosity at very low shear rates sharply increased and showed yield behavior that can be due to the formation of filler particles networks in the melt. At the optimum amount of coupling agent, a minimum in cross over frequency curve against MAPP content is observed. The optimum amount of coupling agent for PP‐talc composites is about 1.5%, and about 3% for PP‐mica formulations. The analysis of viscosity behavior at power‐law high region, revealed the more shear thinning effect of mica than talc on the PP matrix resin. Copyright © 2009 John Wiley & Sons, Ltd.
Conductivity, structure, and thermal properties of chitosan‐based polymer electrolytes with nanofillers
Authors: Aziz N. A. , Majid S. R. , Yahya R. , Arof A. K.
Published: November 2009

This paper focus on the effect of nanosize (<50 nm BET) inorganic alumina (Al2O3) filler on the structural, conductivity, and thermal properties of chitosan‐based polymer electrolytes. Films of chitosan and its complexes were prepared using solution‐casting technique. Different amounts of Al2O3 viz., 3, 4.5, 6, 7.5, 9, 12, and 15 wt% were added to the highest room temperature conducting sample in the chitosan–salt system, i.e. sample containing 60 wt% chitosan–40 wt% NH4SCN. The conductivity value of the sample is 1.29 × 10−4 S cm−1. On addition of 6 wt% Al2O3 filler the ionic conductivity increased to 5.86 × 10−4 S cm−1. The amide and amino peaks in the spectrum of chitosan at 1636 and 1551 cm−1, respectively, shift to lower wavenumbers on addition of salt. The glass transition temperature Tg for the highest conducting composite is 190°C. The increase in Tg with increase in more than 6 wt% filler content is attributed to the increase in degree of crystallinity as proven from X‐ray diffraction studies. Copyright © 2009 John Wiley & Sons, Ltd.
Optimizing annealing steps for crystalline silicon solar cells with screen printed front side metallization and an oxide‐passivated rear surface with local contacts
Authors: Kontermann S. , Wolf A. , Reinwand D. , Grohe A. , Biro D. , Preu R.
Published: November 2009

Silicon solar cells that feature screen printed front contacts and a passivated rear surface with local contacts allow higher efficiencies compared to present industrial solar cells that exhibit a full area rear side metallization. If thermal oxidation is used for the rear surface passivation, the final annealing step in the processing sequence is crucial. On the one hand, this post‐metallization annealing (PMA) step is required for decreasing the surface recombination velocity (SRV) at the aluminum‐coated oxide‐passivated rear surface. On the other hand, PMA can negatively affect the screen printed front side metallization leading to a lower fill factor. This work separately analyzes the impact of PMA on both, the screen printed front metallization and the oxide‐passivated rear surface. Measuring dark and illuminated IV‐curves of standard industrial aluminum back surface field (Al‐BSF) silicon solar cells reveals the impact of PMA on the front metallization, while measuring the effective minority carrier lifetime of symmetric lifetime samples provides information about the rear side SRV. One‐dimensional simulations are used for predicting the cell performance according to the contributions from both, the front metallization and the rear oxide‐passivation for different PMA temperatures and durations. The simulation also includes recombination at the local rear contacts. An optimized PMA process is presented according to the simulations and is experimentally verified. The optimized process is applied to silicon solar cells with a screen printed front side metallization and an oxide‐passivated rear surface. Efficiencies up to 18.1% are achieved on 148.8 cm2 Czochralski (Cz) silicon wafers. Copyright © 2009 John Wiley & Sons, Ltd.
Prenatal alcohol exposure alters phosphorylation and glycosylation of proteins in rat offspring liver
Authors: Fofana Bourlaye , Yao Xing‐Hai , Rampitsch Christof , Cloutier Sylvie , Wilkins John A. , Nyomba B. L. Grégoire
Published: November 2009

To gain more insights into the translational and PTM that occur in rat offspring exposed to alcohol in utero, 2‐D PAGE with total, phospho‐ and glycoprotein staining and MALDI‐MS/MS and database searching were conducted. The results, based on fold‐change expression, revealed a down‐regulation of total protein expression by prenatal alcohol exposure in 7‐day‐old and 3‐month‐old rats. There was an up‐regulation of protein phosphorylation but a down‐regulation of glycosylation by prenatal alcohol exposure in both age groups. Of 31 protein spots examined per group, differentially expressed proteins were identified as ferritin light chain, aldo‐keto reductase, tumor rejection antigen gp96, fructose‐1,6‐bisphosphatase, glycerol‐3‐phosphate dehydrogenase, malate dehydrogenase, and γ‐actin. Increased phosphorylation was observed in proteins such as calmodulin, gluthatione S‐transferase, glucose regulated protein 58, α‐enolase, eukaryotic translation elongation factor 1 β‐2, riboprotein large P2, agmatinase, ornithine carbamoyltransferase, quinolinate phosphoribosyltransferase, formimidoyltransferase cyclodeaminase, and actin. In addition, glycosylation of adenosine kinase, adenosylhomocysteine hydrolase, and 3‐hydroxyanthranilate dioxygenase was reduced. Pathways affected by these protein alterations include cell signaling, cellular stress, protein synthesis, cytoskeleton, as well as glucose, aminoacid, adenosine and energy metabolism. The activity of the gluconeogenic enzyme fructose‐1,6‐bisphosphatase was elevated by prenatal alcohol. The observations may have important physiological implications.
Enzymatic tunneling and kinetic isotope effects: chemistry at the crossroads
Authors: Sen Arundhuti , Kohen Amnon
Published: November 2009

Kinetic isotope effects (KIEs), originally a tool for the physical organic chemist and mechanistic enzymologist, have been instrumental in furthering our understanding of quantum‐mechanical hydrogen tunneling in enzymatic systems. This review focuses on the use of KIE studies to investigate this phenomenon in enzyme‐catalyzed reactions. A number of enzymes wherein KIEs have been used as a probe for H‐tunneling are discussed, including dihydrofolate reductase (DHFR), alcohol dehydrogenase (ADH), and formate dehydrogenase (FDH). Particular emphasis has been placed on the significance of KIE results in exposing the chemical H‐transfer step in the complex kinetic cascades typical to these systems, as well as on questions regarding the influence of protein dynamics on tunneling and, consequently, on the whole enzymatic reaction. Copyright © 2009 John Wiley & Sons, Ltd.
Stress test optimization using an integrated production test and field reliability model
Authors: Honari Bahman , Donovan John , Joyce Toby , Wilson Simon , Murphy Eamonn
Published: November 2009

Numerous papers and texts have been written in the reliability literature regarding the determination of the optimum test duration for a production stress or a burn‐in test. The techniques presented have largely been based on the identification of the change point at which infant mortality has largely been removed from the units. The time‐on‐test is typically the only factor that influences this decision. Few of these models have attempted to integrate the field performance or the influence of warranty costs into this decision. This paper proposes and validates a methodology that integrates the influence of the production test failures and the field performance including their respective costs into a single unified model. The objective is to identify a production test duration that minimizes the overall cost. A Weibull model is initially developed for the production test that incorporates the failure observations in different time segments of the test based on the ability to detect latent defects in the product. A separate Weibull model is then developed for the product's performance in the field that includes the lifetime of the unit. This paper identifies how both these Weibull models can be combined into a single model including both test and field costs with the objective of minimizing the overall cost. The advantage of the proposed technique is that it does not require one to track individual units from production through to the field in order to develop an integrated test and field cost model. Copyright © 2009 John Wiley & Sons, Ltd.
Broder and Karlin's formula for hitting times and the Kirchhoff Index
Authors: Palacios José Luis , Renom José M.
Published: November 2009

We give an elementary proof of an extension of Broder and Karlin's formula for the hitting times of an arbitrary ergodic Markov chain. Using this formula in the particular case of random walks on graphs, we give upper and tight lower bounds for the Kirchhoff index of any N‐ vertex graph in terms of N and its maximal and minimal degrees. We also apply the formula to a closely related index that takes into account the degrees of the vertices between which the effective resistances are computed. We give an upper bound for this alternative index and show that the bound is attained—up to a constant—for the barbell graph. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A density‐functional theory approach to the separation of K2ZrF6 and K2HfF6 via fractional crystallization
Authors: Branken D. J. , Lachmann G. , Krieg H. M. , Bruinsma O. S. L.
Published: November 2009

Because of the low absorption cross‐section for thermal neutrons of zirconium (Zr) as opposed to hafnium (Hf), Zr‐metal must essentially be Hf‐free (<100 ppm Hf) to be suitable for use in nuclear reactors. However, Zr and Hf always occur together in nature, and due to very similar chemical and physical properties, their separation is particularly difficult. Separation can be achieved by traditional liquid–liquid extraction or extractive distillation processes, using Zr(Hf)Cl4 as feedstock. However, the production of K2Zr(Hf)F6 via the plasma dissociation route, developed by the South African Nuclear Energy Corporation Limited (Necsa), could facilitate the development of an alternative separation process. In this theoretical study, the results of density‐functional theory (DFT) simulations of K2Zr(1‐z)HfzF6 solid solutions [using Cambridge Serial Total Energy Package (CASTEP)] are presented, for which the supercell approach was applied in an attempt to determine whether solid solution formation during crystallization from aqueous solutions (fractional crystallization) is thermodynamically possible, which would hinder the separation efficiency of this method. Consequently, the calculated thermodynamic properties of mixing were used to evaluate the separation efficiency of Zr and Hf by fractional crystallization using a thermodynamic model to calculate the relative distribution coefficients. The small mixing enthalpies that were calculated from the DFT results, indicates that lattice substitution of Zr(IV) by Hf(IV) in K2ZrF6 could occur with relative ease. This is not surprising, considering the close similarities between Zr and Hf, and it was therefore concluded that K2Zr(1‐z)HfzF6 solid solution formation might well restrict the separation efficiency of Zr and Hf by fractional crystallization of K2Zr(Hf)F6. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
BaZrO3 photoluminescence property: An ab initio analysis of structural deformation and symmetry changes
Authors: Gurgel Maria F. C. , Moreira Mário L. , Paris Elaine C. , Espinosa José W. M. , Pizani Paulo S. , Varela José A. , Longo Elson
Published: November 2009

This article reports a theoretical study based on experimental results for barium zirconate, BaZrO3 (BZ) thin films, using periodic mechanic quantum calculations to analyze the symmetry change in a structural order‐disorder simulation. Four periodic models were simulated using CRYSTAL98 code to represent the ordered and disordered BZ structures. The results were analyzed in terms of the energy level diagrams and atomic orbital distributions to explain and understand the BZ photoluminescence properties (PL) at room temperature for the disordered structure based on structural deformation and symmetry changes. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Fish use of artificial dike structures in a navigable river
Authors: Hartman Kyle J. , Titus Jennifer L.
Published: November 2009

Artificial structures have been used to potentially increase fish production by providing cover, feeding and spawning areas. In some rivers, the United States Army Corps of Engineers has constructed dikes to provide additional habitat for river fishes and to mitigate for navigation impacts to young fishes. This study was designed to test whether such structures function as viable habitats as evidenced by increased abundances relative to reference areas lacking artificial dike structures. Dikes and reference sites in the Kanawha River, West Virginia were sampled 21 times between July 2002 and October 2003. We found a difference in taxonomic composition among fish using dikes relative to reference areas. Artificial dike structure use was most important among Centrarchidae species, especially juveniles, including black bass and several species ofLepomis. Further, distribution of fish between areas with and without dikes appears most affected by water temperature in 2002 and by short‐term river flow in 2003. These patterns suggest these artificial structures are viable mitigation measures that target and benefit fish of economic interest. Copyright © 2009 John Wiley & Sons, Ltd.
A modified Wilcoxon test for non‐negative distributions with a clump of zeros
Authors: Hallstrom Alfred P.
Published: November 2009

Comparing two samples with a continuous non‐negative score, e.g. a utility score over [0, 1], with a substantial proportion, say 50 per cent, scoring 0 presents distributional problems for most standard tests. A Wilcoxon rank test can be used, but the large number of ties reduces power. I propose a new test, the Wilcoxon rank‐sum test performed after removing an equal (and maximal) number of 0's from each sample. This test recovers much of the power. Compared with a (directional) modification of a two‐part test proposed by Lachenbruch, the truncated Wilcoxon has similar power when the non‐zero scores are independent of the proportion of zeros, but, unlike the two‐part test, the truncated Wilcoxon is relatively unaffected when these processes are dependent. Copyright © 2009 John Wiley & Sons, Ltd.
Comparative Flow Cytometric Analysis of Immunofunctionalized Nanowire and Nanoparticle Signatures
Authors: Prina‐Mello Adriele , Whelan Aine M. , Atzberger Ann , McCarthy Joseph E. , Byrne Fiona , Davies Gemma‐Louise , Coey J. M. D. , Volkov Yuri , Gun'ko Yurii K.
Published: November 2009

Flow cytometry is one of the gold‐standard techniques used in clinical medicine for quantitative immunoassaying. The continuous development of its probes, commonly fluorescent nanoparticles, is important. Lately, the introduction of quantitative multiplexed immunoassay has challenged the use of nanoparticles as probes. Functionalized fluorescent silica‐based magnetic nanowires are investigated under flow cytometry as a novel probe category. The preparation and full characterization of these multimodal nanowires is reported and compared to those of silica‐based magnetic nanoparticles by flow cytometry. Full characterization includes transmission electron microscopy and fluorescence microscopy imaging, flow cytometric assaying, superconducting quantum interference device (SQUID) magnetization, and Mössbauer spectroscopy measurements. This work shows that loaded silica nanowires have intrinsic geometrical advantages when compared to similar spherical particles due to their unique “flow cytometry fingerprint” when utilized as magnetic carriers for immunodetection applications. These advantages account for a 17% yield in detecting the functional binding between THP‐1 and ICAM‐1, by utilizing a much lower concentration than that required for the nanoparticles.
Starch Phosphate Hydrogels. Part II: Rheological Characterization and Water Retention
Authors: Passauer Lars , Liebner Falk , Fischer Klaus
Published: November 2009

Hydrogels with different mechanical properties were synthesized by cross‐linking monostarch monophosphates (MSMP) with various di‐ and tricarboxylic acids (succinic, glutaric, adipic, citric, and maleic acid) by using a semi‐dry method. For a physical characterization water retention and rheological parameters (dynamic viscosity η*, storage and loss moduli G′ and G″) of the hydrogels were determined. Rheomechanical measurements revealed the viscoelasticity and mechanical sturdiness of the gels. Due to their special physical qualities MSMP hydrogels are not only suitable for different industrial applications but also have a big potential to be used as water storing soil amendments improving the efficiency of irrigation especially in arid regions. In order to investigate the suitability of MSMP hydrogels as water storing soil amendments the water retention curves of a sandy soil treated with different amounts of a selected starch phosphate hydrogel were determined.
On the nature of teaching nature of science: Preservice early childhood teachers' instruction in preschool and elementary settings
Authors: Akerson Valarie L. , Buzzelli Cary A. , Donnelly Lisa A.
Published: November 2009

This study explored whether early childhood preservice teachers' concerns about teaching nature of science (NOS) and their intellectual levels influenced whether and how they taught NOS at the preschool and primary (K‐3) levels. We used videotaped classroom observations and lesson plans to determine the science instructional practices at the preschool and primary levels, and to track whether and how preservice teachers emphasized NOS. We used the Stages of Concern Questionnaire (SOCQ) pre‐ and postinternship to determine concerns about NOS instruction, and the Learning Context Questionnaire (LCQ) to determine intellectual levels. We found that neither concerns about teaching NOS nor intellectual level were related to whether and how the preservice teachers emphasized NOS; however, we found that all preservice early childhood teachers began their internships with NOS concern profiles of “worried.” Two preservice teachers' NOS concerns profiles changed as a result of their internships; one to “cooperator” and one to “cooperator/improver.” These two preservice teachers had cooperating teachers who were aware of NOS and implemented it in their own science instruction. The main factors that hindered or facilitated teaching NOS for these preservice teachers were the influence of the cooperating teacher and the use of the science curriculum. The preservice teacher with the cooperating teacher who understood and emphasized NOS herself and showed her how to modify the curriculum to include NOS, was able to explicitly teach NOS to her students. Those in classrooms whose cooperating teachers did not provide support for NOS instruction were unable to emphasize NOS. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47:213–233, 2010
Making formative assessment discernable to pre‐service teachers of science
Authors: Buck Gayle A. , Trauth‐Nare Amy , Kaftan Juliann
Published: November 2009

The purpose of this pragmatic action research study was to explore our re‐conceptualization efforts in preparing pre‐service teachers to guide the inquiry process with formative assessment and subsequently use the understandings to improve our teacher preparation program. The process was guided by two questions: to what extent did course re‐conceptualization efforts lead to a more informed understanding of formative assessment by pre‐service teachers and did strategies enacted in the re‐conceptualized methods course foster or hinder pre‐service teachers' understanding of formative assessment? Data from this study support the following findings: (1) a substantial pre‐ to post‐methods course difference was realized in the pre‐service teachers' understanding of formative assessment; (2) explicit and contextualized approaches to formative assessment in the methods course led to increased understandings by pre‐service teachers; (3) an implicit approach led to improvements in course structure but did not foster pre‐service teachers' understanding of the reflexive nature of formative assessment; and (4) a field‐based case study on elementary science teaching both hindered and fostered our efforts with formative assessment. This study yields implications for pre‐service teacher education on formative assessment. To foster pre‐service teachers' knowledge and skills, we suggest explicit instruction on formative assessment combined with case studies, field experiences, and ongoing reflection. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 402–421, 2010
PART II (Portable ART analyzer)—development of a XRF spectrometer adapted for the study of artworks in the Kunsthistorisches Museum, Vienna
Authors: Buzanich G. , Wobrauschek P. , Streli C. , Markowicz A. , Wegrzynek D. , Chinea‐Cano E. , Griesser M. , Uhlir K.
Published: November 2009

A portable focused‐beam X‐ray fluorescence (XRF) spectrometer was designed and manufactured taking into account a huge variation in material, size and shape of museum objects. The spectrometer is equipped with a vacuum chamber enclosed with a Kapton‐window allowing the detection of chemical elements from Na upwards, which enables the characterization of glass and enamel objects. Two low‐power X‐ray tubes, one with a Mo‐anode the other with a Cr‐anode, operating from 4 to 50 kV and 0 to 2.5 mA with a maximum power of 50 W and a point focus of about 180 µm can be used as excitation source alternatively. A polycapillary lens with a spot size of 150 µm is used for focusing the primary beam to access small details of the different objects, e.g. fine brush strokes in paintings. The vacuum chamber can be evacuated to about 1 mbar.

A miniature camera is installed inside the chamber for inspecting the analyzed area through the Kapton‐window. Two laser pointers mounted inside the chamber coincide with the focal point of the polycapillary at the investigated spot. The excitation and X‐ray fluorescence radiation paths in air are about 1 mm each, minimizing the absorption losses. The spectrometer was designed to maximize the accessibility to all parts of the investigated objects through the use of translation stages and an innovative design of the detection head, especially the vacuum chamber. This article shows the capability of the spectrometer to reach measuring positions in concave parts of objects and presents the determined detection limits of elements. Copyright © 2009 John Wiley & Sons, Ltd.
Structured derivations: a unified proof style for teaching mathematics
Authors: Back Ralph-Johan
Published: November 2009

Structured derivations were introduced by Back and von Wright as an extension of the calculational proof style originally proposed by E. W. Dijkstra and his colleagues. Structured derivations added nested subderivations and inherited assumptions to this style. This paper introduces further extensions of the structured derivation format, and gives a precise syntax and semantics for the extended proof style. The extensions provide a unification of the three main proof styles used in mathematics today: Hilbert-style forward chaining proofs, Gentzen-style backward chaining proofs and algebraic derivations and calculations (in particular, Dijkstra’s calculational proof style). Each of these proof styles can now be directly presented as a structured derivation. Even more importantly, the three proof styles can be freely intermixed in a single structured derivation, allowing different proof styles to be used in different parts of the derivation, each time choosing the proof style that is most suitable for the (sub)problem at hand. We describe here (extended) structured derivations, feature by feature, and illustrate each feature with examples. We show how to model the three main proof styles as structured derivations. We give an exact syntax for structured derivations and define their semantics by showing how a structured derivation can be automatically translated into an equivalent Gentzen-style sequent calculus derivation. Structured derivations have been primarily developed for teaching mathematics at the secondary and tertiary education level. The syntax of structured derivations determines the general structure of the proof, but does not impose any restrictions on how the basic notions of the underlying mathematical domain are treated. Hence, the style can be used for any kind of proofs, calculations, derivations, and general problem solving found in mathematics education at these levels. The precise syntax makes it easy to provide computer support for structured derivations.
Structural basis for chiral substrate recognition by two 2,3‐butanediol dehydrogenases
Authors: Otagiri Masato , Ui Sadaharu , Takusagawa Yuhsuke , Ohtsuki Takashi , Kurisu Genji , Kusunoki Masami
Published: November 2009

2,3‐Butanediol dehydrogenase (BDH) catalyzes the NAD‐dependent redox reaction between acetoin and 2,3‐butanediol. There are three types of homologous BDH, each stereospecific for both substrate and product. To establish how these homologous enzymes possess differential stereospecificities, we determined the crystal structure of l‐BDH with a bound inhibitor at 2.0 Å. Comparison with the inhibitor binding mode of meso‐BDH highlights the role of a hydrogen‐bond from a conserved Trp residue192. Site‐directed mutagenesis of three active site residues of meso‐BDH, including Trp190, which corresponds to Trp192 of l‐BDH, converted its stereospecificity to that of l‐BDH. This result confirms the importance of conserved residues in modifying the stereospecificity of homologous enzymes.
Yeast acetic acid‐induced programmed cell death can occur without cytochrome c release which requires metacaspase YCA1
Authors: Guaragnella Nicoletta , Bobba Antonella , Passarella Salvatore , Marra Ersilia , Giannattasio Sergio
Published: November 2009

To investigate the role of cytochrome c (cyt c) release in yeast acetic acid‐induced programmed cell death (AA‐PCD), wild type (wt) and cells lacking metacaspase (Δyca1), cytochrome c (Δcyc1,7) and both (Δcyc1,7Δyca1) were compared for AA‐PCD occurrence, hydrogen peroxide (H2O2) production and caspase activity. AA‐PCD occurs in Δcyc1,7 and Δcyc1,7Δyca1 cells slower than in wt, but similar to that in Δyca1 cells, in which no cytochrome c release occurs. Both H2O2 production and caspase activation occur in these cells with early and extra‐activation in Δcyc1,7 cells. We conclude that alternative death pathways can be activated in yeast AA‐PCD, one dependent on cyt c release, which requires YCA1, and the other(s) independent on it.
Species‐specific differences in the regulation of the aminoacylation activity of mammalian tryptophanyl‐tRNA synthetases
Authors: Wakasugi Keisuke
Published: November 2009

Tryptophanyl‐tRNA synthetases (TrpRSs) catalyze the aminoacylation of tRNATrp. Previously, I demonstrated that Zn2+‐depleted human TrpRS is enzymatically inactive and that binding of Zn2+ or heme to human TrpRS stimulates its aminoacylation activity. In the present study, bovine and mouse TrpRSs were found to be constitutively active regardless of the presence of Zn2+ or ferriprotoporphyrin IX chloride. Mutagenesis experiments demonstrated that the human H130R mutant is constitutively active and that the bovine R135H, E438A double mutant binds with Zn2+ or heme to enhance its aminoacylation activity as does human wild‐type TrpRS. These results provide the first evidence of species‐specific regulation of TrpRS activity.
Participation of galactosylceramide and sulfatide in glycosynapses between oligodendrocyte or myelin membranes
Authors: Boggs Joan M. , Gao Wen , Zhao Jingsha , Park Hyun-Joo , Liu Yuanfang , Basu Amit
Published: November 2009

The two major glycosphingolipids of myelin, galactosylceramide (GalC) and sulfatide (SGC), interact with each other by trans carbohydrate–carbohydrate interactions. They face each other in the apposed extracellular surfaces of the multilayered myelin sheath produced by oligodendrocytes (OLs). Multivalent galactose and sulfated galactose, in the form of GalC/SGC‐containing liposomes or silica nanoparticles conjugated to galactose and galactose‐3‐sulfate, interact with GalC and SGC in the membrane sheets of OLs in culture. This stimulus results in transmembrane signaling, loss of the cytoskeleton and clustering of membrane domains, suggesting that GalC and SGC could participate in glycosynapses between apposed OL membranes or extracellular surfaces of mature myelin. Such glycosynapses may be important for myelination and/or myelin function.
The role of institutional pressures and organizational culture in the firm's intention to adopt internet‐enabled supply chain management systems
Authors: Liu Hefu , Ke Weiling , Wei Kwok Kee , Gu Jibao , Chen Huaping
Published: November 2009

Drawing upon organizational culture and institutional theory, this study investigates how institutional pressures motivate the firm to adopt Internet‐enabled Supply Chain Management systems (eSCM) and how such effects are moderated by organizational culture. The results of a survey of 131 firms suggest that the dimensions of institutional pressures (i.e., normative, mimetic, and coercive pressures) have differential effects on eSCM adoption intention. While mimetic pressures are not related to eSCM adoption intention, normative and coercive pressures are positively associated with eSCM adoption intention. In addition, organizational culture (i.e., flexibility orientation and control orientation) plays different roles in the relationships between these three dimensions of institutional pressures and eSCM adoption intention. While flexibility orientation negatively moderates the effects of coercive pressures and positively moderates the effects of mimetic pressures, control orientation positively moderates the effects of coercive and normative pressures and negatively moderates the effects of mimetic pressures. Implications and suggestions for future research are provided.
SOBOLEV INEQUALITIES FOR ORLICZ SPACES OF TWO VARIABLE EXPONENTS
Authors: HÄSTÖ PETER , MIZUTA YOSHIHIRO , OHNO TAKAO , SHIMOMURA TETSU
Published: November 2009

Our aim in this paper is to deal with Sobolev's embeddings for Sobolev–Orlicz functions with ∇u∈Lp(·)logLq(·)(Ω) for Ω ⊂n. Herepandqare variable exponents satisfying natural continuity conditions. Also the case whenpattains the value 1 in some parts of the domain is included in the results.
ON THE MULTIPLICITY OF SOLUTIONS FOR NON-LINEAR PERIODIC PROBLEMS WITH THE NON-LINEARITY CROSSING SEVERAL EIGENVALUES
Authors: KYRITSI SOPHIA TH. , PAPAGEORGIOU NIKOLAOS S.
Published: November 2009

In this paper we consider a non-linear periodic problem driven by the scalar p-Laplacian and with a non-smooth potential. We assume that the multi-valued right-hand-side non-linearity exhibits an asymmetric behaviour at ±∞ and crosses a finite number of eigenvalues as we move from −∞ to +∞. Using a variational approach based on the non-smooth critical-point theory, we show that the problem has at least two non-trivial solutions, one of which has constant sign. For the semi-linear (p = 2), smooth problem, using Morse theory, we show that the problem has at least three non-trivial solutions, again one with constant sign.
ZINBIEL ALGEBRAS AND COMMUTATIVE ALGEBRAS WITH DIVIDED POWERS
Authors: DOKAS IOANNIS
Published: November 2009

In this paper, we prove that any Zinbiel algebra can be endowed with the structure of commutative algebra with divided powers. We introduce the notion of universal enveloping Zinbiel algebra of a commutative algebra with divided powers algebras. We prove that the free divided powers algebra on a free moduleM, is the divided powers sub-algebra generated byM, of the divided powers algebra induced by the free Zinbiel algebra onM. Finally, we construct a basis for the enveloping Zinbiel algebra.
Dynamics of strain-hardening and strain-softening capsules in strong planar extensional flows via an interfacial spectral boundary element algorithm for elastic membranes
Authors: DODSON W. R. , DIMITRAKOPOULOS P.
Published: November 2009

In the present study we investigate the dynamics of initially spherical capsules (made from elastic membranes obeying the strain-hardening Skalak or the strain-softening neo-Hookean law) in strong planar extensional flows via numerical computations. To achieve this, we develop a three-dimensional spectral boundary element algorithm for membranes with shearing and area-dilatation tensions in Stokes flow. The main attraction of this approach is that it exploits all the benefits of the spectral methods (i.e. high accuracy and numerical stability) but without creating denser systems. To achieve continuity of the interfacial geometry and its derivatives at the edges of the spectral elements during the interfacial deformation, a membrane-based interfacial smoothing is developed, via a Hermitian-like interpolation, for both the interfacial shape and the membrane elastic forces. Our numerical results show that no critical flow rate exists for both Skalak and neo-Hookean capsules in the moderate and strong planar extension flows considered in the present study. As the flow rate increases, both capsules reach elongated ellipsoidal steady-state configurations; the cross-section of the Skalak capsule preserves its elliptical shape, while the neo-Hookean capsule becomes more and more lamellar. The curvature at the pointed edges of these elongated steady-state shapes shows a very fast increase with the flow rate. The large interfacial deformations are accompanied with the development of strong membrane tensions especially for the strain-hardening Skalak capsule; the computed increase of the membrane tensions with the flow rate or the shape extension can be used to predict rupture of a specific membrane (with known lytic tension) due to excessive tensions. The type of the experiment imposed on the capsule as well as the applied flow rate affect dramatically the time evolution of the capsule edges owing to the interaction of the hydrodynamic forces with the membrane tensions; when a spherical Skalak capsule is let to deform in a strong flow, very large edge curvatures (with respect to the steady-state value) are developed during the transient evolution.
Electrically driven vortices in a weak dipolar magnetic field in a shallow electrolytic layer
Authors: FIGUEROA ALDO , DEMIAUX FRANÇOIS , CUEVAS SERGIO , RAMOS EDUARDO
Published: November 2009

Steady dipolar vortices continuously driven by electromagnetic forcing in a shallow layer of an electrolytic fluid are studied experimentally and theoretically. The driving Lorentz force is generated by the interaction of a dc uniform electric current injected in the thin layer and the non-uniform magnetic field produced by a small dipolar permanent magnet (0.33 T). Laminar velocity profiles in the neighbourhood of the zone affected by the magnetic field were obtained with particle image velocimetry in planes parallel and normal to the bottom wall. Flow planes at different depths of the layer were explored for injected currents ranging from 10 to 100 mA. Measurements of the boundary layer attached to the bottom wall reveal that owing to the variation of the field in the normal direction, a slightly flattened developing profile with no shear stresses at the free surface is formed. A quasi-two-dimensional magnetohydrodynamic numerical model that introduces the non-uniformity of the magnetic field, particularly its decay in the normal direction, was developed. Vertical diffusion produced by the bottom friction was modelled through a linear friction term. The model reproduces the main characteristic behaviour of the electromagnetically forced flow.
Cholesteatoma in three dimensions: a teaching tool and an aid to improved pre-operative consent
Authors: Morris D P , Van Wijhe R G
Published: November 2009

Background:

Otological surgeons face two recurring challenges. Firstly, we must foster an appreciation of the complex, three-dimensional anatomy of the temporal bone in order to enable our trainees to operate safely and independently. Secondly, we must explain to our patients the necessity for surgery which carries the potential for serious complication.

Methods:

Amira® software was applied to pre-operative computed tomography images of temporal bones with cholesteatoma, to create three-dimensional computer images. Normal structures and cholesteatoma were displayed in a user-friendly, interactive format, allowing both trainee and patient to visualise disease and important structures within the temporal bone.

Results:

Three cases, and their three-dimensional computer models are presented. Zoom, rotation and transparency functions complemented the three-dimensional effect.

Conclusion:

These three-dimensional models provided a useful adjunct to cadaveric temporal bone dissection and surgical experience for our residents' teaching programme. Also, patients with cholesteatoma reported a better understanding of their pre-operative condition when the models were used during the consenting process.
Changes in facial nerve function, morphology and neurotrophic factor expression in response to three types of nerve injury
Authors: Zhang L , Fan Z , Han Y , Xu L , Luo J , Li J , Wang H
Published: November 2009

Objective:

To study the changes in facial nerve function, morphology and neurotrophic factor 3 expression in response to three types of nerve injury.

Materials and methods:

Changes in facial nerve function (in terms of blink reflex, vibrissae movement and position of nasal tip) were assessed in 45 rats in response to three types of nerve injury: partial section of the extratemporal segment (group one); partial section of the facial canal segment (group two); and complete transection of the facial canal segment (group three). All facial nerves were then dissected out from the sacrificed animals, on the first, seventh or 21st post-operative day, and the injured segment bisected for subsequent analysis. Morphological change and neurotrophic factor 3 expression in these facial nerve segments were evaluated by means of improved trichrome staining and immunohistochemical analysis, respectively.

Results:

Facial nerve function was more severely damaged and recovery was slower in group two compared with group one, although the facial nerve injury had been identical at the two sites involved. In group three (complete facial canal transection), scattered degenerative fibres were observed at the transection site on the seventh post-operative day. The number of degenerated fibres, assessed on the seventh post-operative day, was markedly increased in group two compared with group one. On the seventh post-operative day, axonal expression of neurotrophic factor 3 was strongly positive, whereas expression in Schwann cells was only weakly positive.

Conclusions:

The facial palsy of the group two rats was more severe than that of group one rats, although their facial nerve function had partly recovered on the 21st post-operative day. Fibre degeneration was not only dispersed throughout the injury site but also occurred throughout the length of the nerve. Neurotrophic factor 3 immunoreactivity increased in facial nerve fibres after partial transection.
Frequency and management of epistaxis in schools
Authors: Robertson A , King R , Tomkinson A
Published: November 2009

Study objectives:

To investigate the frequency and management of epistaxis in schools.

Study design:

A postal survey of schools.

Results:

One hundred and fifty-seven questionnaires were posted out to 41 secondary schools (students aged 11–18 years) and to 116 primary schools (students aged four to 11 years). One hundred and twelve completed questionnaires were returned, 32 from secondary schools and 80 from primary schools. Most schools stated that they encountered a nose bleed once per month. The commonest method of treating a nose bleed was to pinch the top of the nose (an ineffective method), although pinching the bottom of the nose was almost as common. Only a minority of primary and secondary schools (37.5 and 25 per cent, respectively) had a policy for dealing with nose bleeds. Despite many respondents reportedly using an ineffective method, only two stated that they did not feel confident in dealing with nose bleeds.

Conclusion:

Nose bleeds in school students are common, and management frequently deviates from recommended guidelines.
Transnasal endoscopic repair of bilateral congenital choanal atresia: controversies
Authors: Eladl Hesham Mohammad
Published: November 2009

Objective:

To evaluate current concerns about transnasal endoscopic repair of bilateral congenital choanal atresia, regarding technical difficulties, prognostic factors and important controversies.

Patients and methods:

Ten infants with bilateral congenital choanal atresia, aged from 3 to 27 days (mean, 11.2 days) were included. All cases underwent transnasal endoscopic repair and were clinically and endoscopically monitored.

Results:

Of the seven patients treated with stenting, five remained patent and two required minor debridement (with complete patency thereafter). Of the three patients treated without stenting, one remained patent and two required minor debridement (with patency thereafter).

Conclusions:

Transnasal endoscopic repair of bilateral congenital choanal atresia is a safe and successful technique. The use of powered instrumentation in neonatal patients requires experience and a correctly sized drill. Stenting with an appropriate nasal tube for a suitable period is favoured, especially in hospitalised patients.
Is there a role for flexible oesophagogastroscopy in upper aerodigestive tract squamous cell carcinoma?
Authors: Beech T J , Trotter M I , McDermott A L , Mandal W , Batch A J
Published: November 2009

Introduction:

There is growing evidence to suggest that reflux (both laryngopharyngeal and gastroesophageal) has a role in the development of upper aerodigestive tract squamous cell carcinoma. This study discusses the role of identifying reflux in this patient group, and its prevalence.

Methods:

Prospective review of patients with head and neck cancer undergoing flexible oesophagogastroscopy as part of their diagnostic investigation.

Results:

Forty-five consecutive patients were identified. All patients were found to have evidence of oesophagitis, with 28 having oesophageal erosions and two Barrett's oesophagitis.

Conclusion:

Flexible oesophagogastroscopy is a useful test in patients with upper aerodigestive tract squamous cell carcinoma.