bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Hydrogen–Oxygen Systems in the Electrical Discharge. VII. Deuterium Isotope Effects in the Chemistry of the Hydrogen Polyoxides
Authors: Arnau José L. , Giguère Paul A.
Published: May 2006

The kinetics of oxygen evolution on warming the trapped products (at −196 °C) from water or hydrogen peroxide vapor dissociated in a glow discharge were studied by the manometric method. Under closely controlled conditions it was possible to distinguish clearly the decomposition of the two intermediates, H2O3 and H2O4. The latter begins to decompose measurably following crystallization of the glassy solid at about −115°; the trioxide decomposes readily between −50 and −35°. Typically, the yields of H2O3 from dissociated water vapor were of the order of 3 to 5 mol%; those of H2O4, only about one-tenth as much. Varying the distance between the microwave discharge and the cold trap was found to affect differently the yields of the various products. Those of water and peroxide showed a simple, direct correlation; the minor constituents H2O3 and H2O4 followed entirely different patterns. Only a small fraction of the peroxide is formed via the H2O4 intermediate in these systems. Less water, and more of the higher oxides, were obtained from dissociated hydrogen peroxide than from water vapor.The deuterated systems showed some unusual isotope effects. The yields of D2O3 were always higher (up to twice and even more) than those of H2O3 under similar conditions. The other products showed little or no such effect, except for occluded oxygen and ozone which decreased by about half. Finally, the deuterium polyoxides decompose at slightly higher temperatures (10 to 15°) than their hydrogen analogs. Mechanisms are proposed for the formation and decomposition of the polyoxides.
Synthesis and Characterization of Some Dibasic Tridentate Schiff Base Ligands
Authors: Alyea Elmer C. , Malek Abdul
Published: May 2006

not available
Stereoselective Total Synthesis of Copa and Ylango Sesquiterpenoids: (−)-Copacamphene, (−)-Cyclocopacamphene, (+)-Sativene, (+)-Cyclosativene
Authors: Piers Edward , Geraghty M. Bert , Smillie R. Dean , Soucy Marcel
Published: May 2006

Stereoselective total syntheses of the tricyclic sesquiterpenoids (−)-copacamphene (1) and (+)-sativene (3) and of the related tetracyclic compounds (−)-cyclocopacamphene (2) and (+)-cyclosativene (4) are described. An efficient four-step synthetic sequence was employed to convert the bicyclic dione 5 into the olefinic ketone 8. The latter compound was converted in four steps into the olefinic alcohol 23. Eliminative cyclization of the corresponding tosylate 25 gave (−)-copacamphene (1) in high yield. In similar fashion, (+)-sativene (3) was obtained by cyclization of the olefinic tosylate 42, which in turn was derived via a four-step synthetic sequence from the olefinic ketone 9. Oxidation of the olefinic alcohol 23 afforded the aldehyde 34. Conversion of the latter compound into the p-tosylhydrazone 35, followed by pyrolysis of the corresponding lithium salt 36, gave the pyrazoline 37. Photolysis of 37 afforded, in high yield, (−)-cyclocopacamphene (2). Similarly, (+)-cyclosativene (4) was obtained from the olefinic alcohol 41 via the pyrazoline 46.
Acylsilane Photolyses: 1,1-Diphenyl-1-Silacyclohexanone-2 in Cyclohexane
Authors: Brook A. G. , Pierce J. B. , Duff J. M.
Published: May 2006

Photolysis of the cyclic acylsilane 1,1-diphenyl-l-silacyclohexanone-2 yields 1,1-diphenyl-1-silacyclopentane and two dimeric products whose structures were established by chemical and spectroscopic methods. A mechanism involving a siloxycarbene intermediate which is trapped by a second acylsilane molecule, is proposed for the formation of the dimers.
Kinetics and Equilibrium of Binding of Fe3+ by a Fulvic Acid: A Study by Stopped Flow Methods
Authors: Langford Cooper H. , Khan Tahir R.
Published: May 2006

The first report of a rate of binding of a metal ion (Fe3+) by a soluble fulvic acid is derived from stopped flow measurements. The rate of complex formation is normal in Wilkins' sense and similar to that for sulfosalicylic acid. Dissociation is slow (t1/2 > 10 s). The binding of Fe3+ by the fulvic acid in acid solution, pH = 1–2.5, was investigated by kinetic analysis in which the reaction of free Fe3+ with sulfosalicylic acid was followed by stopped flow spectrophotometry on a time scale short compared to release of Fe3+ by fulvic acid. Conditional equilibrium constants found were 1.5 ± 0.3 × 104 at pH = 1.5 and 2.5, and 2.8 ± 0.3 × 103 at pH = 1.0 at 25 °C (ionic strength 0.1).
Geminate Recombination of Ion Pairs In The Radiolysis of Dense Hydrocarbon Gases
Authors: Nishikawa Masaru
Published: May 2006

The distribution functions of ion-electron pair separation distances in irradiated hydrocarbon gases are transformed into those of neutralization times by means of the r3 rule of time-distance obtained under the approximation that Coulomb field predominates in their mutual diffusion. In this approximation lifetime distribution is a function of (3Drc)1/3/b, where D is the total diffusion constant, D++De, rc is the Onsager distance, and b is the characteristic distance of the respective spatial distribution function. Using the values of parameters previously estimated for supercritical hydrocarbons, it was found that for butanes the lifetime in the gas phase at density[Formula: see text] is shorter than that in the liquid phase at room temperature.
Diprotonation of 5-Acyl-1,2,3,4,5-pentamethylcyclopentadienes
Authors: Childs Ronald F. , Zeya Maung
Published: May 2006

5-Acyl-1,2,3,4,5-pentamethylcyclopentadienes could potentially be protonated on either or both of two sites, the diene moiety in the five-membered ring or the carbonyl oxygen. The protonation of a series of 5-acylpentamethylcyclopentadienes has been examined and evidence is presented which shows that the former site is essentially completely protonated in FSO3H and that the carbonyl oxygen is also partially protonated. The extent of diprotonation is shown to be dependent both on the nature of the acyl groups and also the acidity of the medium. At temperatures above 40 °C these protonated species undergo a clean fragmentation to give protonated pentamethylcyclopentadiene from which pentamethylcyclopentadiene can be recovered in good yield on quenching the acid solution.
Isotope Effect Studies on Elimination Reactions. XI. The Nature of the Transition State for the E2 Reaction of 2-Phenylethyldimethylanilinium Salts Containing Substituents in the Aniline Ring with Sodium Ethoxide in Ethanol
Authors: Schmid Peter , Bourns Arthur Newcombe
Published: May 2006

Kinetic isotope effects have been determined for the E2 reactions of a series of 2-phenylethyldimethylanilinium salts containing substituents in the aniline ring with sodium ethoxide in ethanol at 40 °C. The nitrogen isotope effect, (k14/k15−1)100, is not very sensitive to substituent changes but appears to increase slightly with increasing electron-withdrawing ability of the substituents, i.e., 1.19 ± 0.07, 1.13 ± 0.06, 1.12 ± 0.08, 1.30 ± 0.07, and 1.32 ± 0.06 for p-OCH3, p-CH3, p-H, p-Cl, and, m-CF3, respectively. The hydrogen–deuterium isotope effects pass through a minimum in the region of the unsubstituted compound and increase both with increasing electron-donating as well as with electron-withdrawing power of the substituents, i.e. kH/kD = 4.70 ± 0.06, 4.61 ± 0.04, 4.51 ± 0.04, 4.53 ± 0.09, 5.00 ± 0.07, and 5.39 ± 0.07 for p-OCH3, p-CH3, p-H, p-Cl, m-CF3, and p-CF3, respectively. The results are discussed in terms of recent theoretical treatments of the effect of structural variations in the reactants on the nature of the transition state of E2 elimination reactions. The conclusion is reached that the transition states in the present reaction series can be characterized as 'central with slight carbanion character' and that the effect of a change in the ability of the leaving group on the structure of the transition state manifests itself mainly in the direction perpendicular to the reaction coordinate. A simple novel hypothesis is formulated which emphasizes the importance of the location of the transition state in a More O'Ferrall-type potential energy diagram in determining its sensitivity to structural changes in the reactants.
The Direct Formation of 3-Vinylthiophenes Using Butadienylphosphonium Salts
Authors: McIntosh John M. , Seguin Frederick P.
Published: May 2006

The reaction of α-mercaptoaldehydes and ketones with 1,3-butadien-1-yltriphenylphosphonium salts (4) unexpectedly leads to 3-vinylthiophenes and triphenylphosphine. This result is attributed to the retardation of the usual Wittig cyclization reaction which allows the competing reaction to occur.
Stereochemical Determination of Key Substrates of the Cope Rearrangement by 13C Nuclear Magnetic Resonance Spectroscopy
Authors: Wigfield Donald C. , Taymaz Kevser
Published: May 2006

The 13C n.m.r. spectra of two key substrates of the Cope rearrangement (compounds 3 and 5) have been assigned and compared with those of their monosaturated analogs. The spectra are consistent with the substrates being stereochemically homogeneous and with the E configuration around the trisubstituted double bond.
Fermi-Resonance Minima in the Vibrational Spectrum of Water in Crystalline Hydrates
Authors: Othen David A. , Knop Osvald , Falk Michael
Published: May 2006

The infrared absorption and Raman spectra of polycrystalline tetrachlorocuprate(II) dihydrates M2CuCl4.2H2O (M = K, Rb, Cs, NH4) contain minima in the OH stretching region which sharpen at low temperature. These minima are shown to be 'Evans holes', or negative absorption features, caused by Fermi resonance between the broad and intense H2O stretching fundamental V1 and a relatively narrow band due to the overtone of the H2O bending vibration 2V2. Our findings confirm that Fermi resonance can lead to unusual spectral features, which must be taken into account in the analysis of the stretching region of the spectra of H2O and D2O in condensed phases, as has been done by Scherer etal. for the spectrum of liquid water.
Systemic inflammation and remote organ damage following bilateral femur fracture requires Toll-like receptor 4
Authors: Levy Ryan M. , Prince Jose M. , Yang Runkuan , Mollen Kevin P. , Liao Hong , Watson Gregory A. , Fink Mitchell P. , Vodovotz Yoram , Billiar Timothy R.
Published: May 2006

Extensive soft tissue injury and bone fracture are significant contributors to the initial systemic inflammatory response in multiply injured patients. Systemic inflammation can lead to organ dysfunction remote from the site of traumatic injury. The mechanisms underlying the recognition of peripheral injury and the subsequent activation of the immune response are unknown. Toll-like receptors (TLRs) recognize microbial products but also may recognize danger signals released from damaged tissues. Here we report that peripheral tissue trauma initiates systemic inflammation and remote organ dysfunction. Moreover, this systemic response to a sterile local injury requires toll-like receptor 4 (TLR4). Compared with wild-type (C3H/HeOuJ) mice, TLR4 mutant (C3H/HeJ) mice demonstrated reduced systemic and hepatic inflammatory responses to bilateral femur fracture. Trauma-induced nuclear factor (NF)-κB activation in the liver required functional TLR4 signaling. CD14−/− mice failed to demonstrate protection from fracture-induced systemic inflammation and hepatocellular injury. Therefore, our results also argue against a contribution of intestine-derived LPS to this process. These findings identify a critical role for TLR4 in the rapid recognition and response pathway to severe traumatic injury. Application of these findings in an evolutionary context suggests that multicellular organisms have evolved to use the same pattern recognition receptor for surviving traumatic and infectious challenges.
Insurable Interest: Can the Modern Law be Adopted in Takaful Operations?
Authors: Ma'sum Billah
Published: May 2006

No Abstract
Comment on Kuwaiti Law No. 2 of 1999 concerning the Disclosure of Interests in Shares in the Light of Comparative Laws
Authors: Al-Melhem
Published: May 2006

No Abstract
The Islamic Law of Guarantees
Authors: Foster
Published: May 2006

No Abstract
UAE: Recent Developments
Authors: Afridi & Angell
Published: May 2006

No Abstract
Documentary Credits in the Abu Dhabi Court
Authors:   Tamimi
Published: May 2006

No Abstract
Reduction/oxidation-phosphorylation control of DNA binding in the bZIP dimerization network
Authors: Amoutzias Gregory D , Bornberg-Bauer Erich , Oliver Stephen G , Robertson David L
Published: May 2006

Background

bZIPs are transcription factors that are found throughout the eukarya from fungi to flowering plants and mammals. They contain highly conserved basic region (BR) and leucine zipper (LZ) domains and often function as environmental sensors. Specifically, bZIPs frequently have a role in mediating the response to oxidative stress, a crucial environmental signal that needs to be transduced to the gene regulatory network.

Results

Based on sequence comparisons and experimental data on a number of important bZIP transcription factors, we predict which bZIPs are under redox control and which are regulated via protein phosphorylation. By integrating genomic, phylogenetic and functional data from the literature, we then propose a link between oxidative stress and the choice of interaction partners for the bZIP proteins.

Conclusion

This integration permits the bZIP dimerization network to be interpreted in functional terms, especially in the context of the role of bZIP proteins in the response to environmental stress. This analysis demonstrates the importance of abiotic factors in shaping regulatory networks.
A β1,4-galactosyltransferase is required for Bmp2-dependent patterning of the dorsoventral axis during zebrafish embryogenesis
Authors: Machingo Quentin J. , Fritz Andreas , Shur Barry D.
Published: May 2006

Complex carbohydrates are highly polymorphic macromolecules that are involved in diverse biological processes; however, a detailed understanding of their function remains obscure. To better define the roles of complex carbohydrates during vertebrate embryogenesis, we have initiated an analysis of glycosyltransferase function using the zebrafish system. In this study, we report the characterization of a zebrafish β1,4-galactosyltransferase(GalT), which has substantial homology with mammalian β4GalT5 and is expressed zygotically throughout the zebrafish embryo. Downregulating the expression of β4GalT5 by injection of specific morpholino oligonucleotides results in dorsalized zebrafish embryos, suggesting a role ofβ4GalT5 in Bmp2-mediated specification of the dorsoventral axis. Consistent with this, morpholino-injected embryos have ventrally expanded chordin expression and reduced activation of the Bmp-dependent transcription factors Smad1/5/8. Because other growth factors, such as Egf and Fgf, require binding to extracellular proteoglycans for delivery and/or binding to their cognate receptors, we examined whether proteoglycans isolated from control and morpholino-injected embryos show differential binding affinities for Bmp2. In this regard, proteoglycans isolated from β4GalT5 morphant embryos are underglycosylated and are unable to bind recombinant Bmp2 as efficiently as proteoglycans from control-injected embryos, whereas the binding of Bmp7 is relatively unaffected. These results suggest that β4GalT5 is a previously unidentified zebrafish galactosyltransferase that is essential for proper patterning of the dorsoventral axis by regulating Bmp2 signaling. Furthermore,this work demonstrates that a relatively simple carbohydrate modification to endogenous proteoglycans can modulate the specificity of cytokine signaling.
Brightness stabilisation of bleached high-yield pulps by novel sulfur-containing inhibitors
Authors: Beyer Mario , Fischer Klaus , Süss Hans-Ulrich
Published: May 2006

The stabilisation of a peroxide-bleached chemothermomechanical pulp against light-induced yellowing by novel sulfur-containing radical-scavenging compounds was investigated. Substances were identified that lack the unpleasant odour typical for compounds containing thiol groups. High inhibition effects were observed when the sulfur compounds were combined with small amounts of hindered amines and UV absorbers. A novel group of thiols isolated from biomatter was among the sulfur-containing inhibitors. Photoyellowing could be avoided for 3 years in real conditions when the inhibitors were applied as part of a coating. The ability of the thiol compounds to scavenge phenoxy radicals was demonstrated by ESR spectroscopy of irradiated chemithermomechanical pulp sheets. The results are encouraging for efficient brightness stabilisation of high-yield pulps.
Effect of a waterproof agent on gypsum particleboard properties
Authors: Deng Yuhe , Xuan Ling , Feng Qian
Published: May 2006

This paper describes the influence of the addition of an organosilicon waterproof agent on the properties of gypsum particleboard (GPB). Test results showed that the additive at an appropriate concentration reduces the thickness swelling (TS) and water absorption (WA), and increases the mechanical properties. TS was lowered to ∼1.6% and internal bond strength (IB) was increased to ∼0.4 MPa when 3% organosilicon agent was added. Accordingly, the TS was reduced by 53% and the IB increased by 45% relative to control board without additives. The modulus of rupture (MOR) and modulus of elasticity (MOE) were also increased in the presence of the organosilicon waterproof agent. The effect was pronounced for MOR. On the other hand, too high a content of organosilicon additive had a negative effect and the corresponding property values were poorer. X-Ray diffraction revealed that the content of gypsum dihydrate increased in the presence of the additive, but other chemical changes were not observed. Scanning electron microscopy (SEM) confirmed that the crystal size in gypsum was reduced is the presence of the additive.
Subcutaneous hyalohyphomycosis caused by Acremonium recifei: case report
Authors: Zaitz Clarisse , Porto Edward , Heins-Vaccari Elisabeth Maria , Sadahiro Aya , Ruiz Ligia Rangel Barbosa , Müller Helena , Lacaz Carlos da Silva
Published: May 2006

We present a case of subcutaneous hyalohyphomycosis due to Acremonium recifei, a species whose habitat is probably the soil, first identified in 1934 by Arêa Leão and Lobo in a case of podal eumycetoma with white-yellowish grains and initially named Cephalosporium recifei. A white immunocompetent female patient from the state of Bahia, Brazil, with a history of traumatic injury to the right hand is reported. The lesion was painless, with edema, inflammation and the presence of fistulae. Seropurulent secretion with the absence of grains was present. Histopathological examination of material stained with hematoxylin-eosin showed hyaline septate hyphae. A culture was positive for Acremonium recifei. Treatment with itraconazole, 200 mg/day, for two months led to a favorable course and cure of the process. We report for the first time in the literature a case of subcutaneous hyalohyphomycosis due to Acremonium recifei in a immunocompetent woman. Treatment with itraconazole 200 mg/day, for two months, resulted in cure.
Fracionamento e disponibilidade de zinco por diferentes extratores em solos incubados com lodo de esgoto
Authors: Araújo Josângela do Carmo Trezena de , Nascimento Clístenes Williams Araújo do
Published: May 2006

O lodo de esgoto pode constituir um problema ambiental em virtude da necessidade de adequada disposição final. Dado seu elevado teor de matéria orgânica e nutrientes, tem-se considerado a possibilidade de sua utilização como fertilizante; entretanto, alguns cuidados relacionados com a biodisponibilidade e a forma de metais pesados no solo devem ser observados. No caso do Zn, um dos metais em maior teor no lodo de esgoto, o conhecimento das formas e as relações com os teores disponíveis são importantes para a previsão do comportamento desse metal no solo. Este trabalho objetivou avaliar a distribuição entre diferentes frações (trocável, matéria orgânica, óxido de ferro amorfo, óxido de ferro cristalino, residual) e a disponibilidade de Zn pelos extratores DTPA, EDTA, Mehlich-1 e Mehlich-3 em solos incubados com lodo de esgoto e suas relações com a absorção de Zn por plantas de milho. Foram utilizados dois tipos de solos (Argissolo e Latossolo) com diferentes características, aos quais foram adicionadas cinco doses de lodo de esgoto (equivalentes a 0; 40,5; 81; 162 e 243 Mg ha-1). Após período de incubação de 180 dias, a incorporação do lodo de esgoto proporcionou aumento na produção de matéria seca da parte aérea do milho e ausência de toxidez de Zn nos dois solos. A dose máxima de Zn a ser adicionada por lodo de esgoto mostrou-se segura quanto à contaminação de Zn nos solos e plantas, para as condições estudadas, conforme preconizam as normas da USEPA. Os maiores teores de Zn foram encontrados nas frações: Residual > Matéria Orgânica > Trocável > Óxido de Ferro Cristalino > Óxido de Ferro Amorfo. A maior recuperação de Zn das amostras foi obtida com os extratores ácidos (Mehlich-1 e Mehlich-3); no entanto, todos foram eficientes na predição da disponibilidade do elemento.
Alteração física e morfológica em solos cultivados sob sistema tradicional de manejo
Authors: Soares Jorge Luís Nascimento , Espíndola Carlos Roberto , Castro Selma Simões de
Published: May 2006

O presente trabalho foi realizado numa área agrícola situada no município de Bariri (SP), em área cultivada com citros (Citrus sinensis), onde foram estudadas algumas alterações pedológicas decorrentes de um longo período de exploração agrícola com sistema tradicional de manejo do solo. Foi estabelecida uma condição de seqüência topográfica para que pudesse ser avaliada a importância da posição dos solos no relevo sobre as modificações de alguns dos seus atributos físicos. As observações foram realizadas em campo e laboratório, em perfis verticais situados nos terços: superior, médio e inferior da encosta em um Latossolo Vermelho com alguns atributos avaliados estatisticamente por meio de teste de comparação de médias. Houve alterações na densidade do solo e da macroporosidade, principalmente nas posições mais baixas do relevo. Nestas posições, mais argilosas, há preenchimento dos espaços vazios, com a formação de estrutura em blocos, ocorrendo concomitantemente com a estrutura microagregada. Os tratos culturais promoveram grandes alterações na estrutura dos solos, mesmo em camadas relativamente profundas. O estudo ressaltou a importância de observações morfológicas detalhadas dos perfis de solo, em virtude da grande variabilidade dos atributos pedológicos a uma curta distância, sendo observados, num mesmo horizonte do perfil, setores compactados ao lado de bolsões desagregados, o que atesta a necessidade de serem considerados tanto os gradientes verticais (em cada perfil) como os laterais (ao longo da toposseqüência) no estudo das variações temporais dos parâmetros pedológicos.
Avaliação dos danos causados pelo desmonte com explosivos no contorno de galerias subterrâneas a partir de um modelo baseado em medidas de velocidade de partícula
Authors: Silva João Carlos Ribeiro Monteiro da , Silva Valdir Costa e
Published: May 2006

A ação das ondas de choque de detonações realizadas para a abertura de galerias subterrâneas induz danos ao maciço rochoso remanescente. Esse trabalho tem por objetivo avaliar a extensão desses danos, aplicando uma metodologia baseada no modelo de Holmberg e Persson, ao caso da mina subterrânea de Agalmatolito da LAMIL em Pará de Minas, MG. A partir de medidas de velocidade de partícula e das velocidades de propagação da onda primária, determinaram-se limites de vibração, acima dos quais são esperados danos. Utilizando a equação de atenuação das vibrações no campo próximo, desenvolvida para o local, calcularam-se os raios de duas zonas de dano em torno de duas classes de maciço: 0,24 m (raio de dano crítico) e 1,64 m (raio de dano mínimo) para o Metariolito; e 1,29 m e 1,59 m, respectivamente, para o Agalmatolito. Confrontando-se os resultados obtidos com aqueles constantes na literatura, verificou-se consistência com os valores encontrados para rochas semelhantes. Uma comparação da posição efetiva da superfície escavada com aquela prevista pelo modelo apresentou um erro de estimativa médio de 0,06 m.
Bacias de retenção para gestão do escoamento: métodos de dimensionamento e instalação
Authors: Lima Herlander Mata , Silva Evaristo Santos , Raminhos Cristina
Published: May 2006

Esse trabalho apresenta uma metodologia integrada para gerir o excesso do escoamento através de bacias de retenção. Partindo de modelos hidrológicos de estimação de caudais de escoamento, nas bacias de drenagem, combinam-se os métodos expeditos (empíricos) e numérico, num procedimento integrado para o dimensionamento de bacias de retenção, incluindo as estruturas hidráulicas associadas (e.g. descarregador de orifício, descarregador de soleira espessa).A abordagem que se apresenta engloba, também, as recomendações relacionadas aos critérios de implantação da bacia de retenção, tais como, o declive dos taludes e a profundidade.A metodologia é aplicada a um estudo de caso sintético, tendo-se realçado a importância da aplicação dos métodos expeditos para obtenção de resultados preliminares, bem como a necessidade de aplicação do método numérico de Level Pool Routing, para o dimensionamento final da bacia de retenção e simulação do comportamento dinâmico.
Efeitos da suplementação aguda de aspartato de arginina na fadiga muscular em voluntários treinados
Authors: Sales Ricardo Pombo , Miné Carlos Eduardo César , Franco Andréia Dellú , Rodrigues Érika Lima , Silva Renato de Souza e , Cogo José Carlos , Lopes-Martins Rodrigo A.B. , Osorio Rodrigo Lazo , Ribeiro Wellington
Published: May 2006

A atividade física influi em mecanismos específicos responsáveis pela redução da produção de força e conseqüentemente à fadiga. A preocupação em melhorar o desempenho físico tem sido propostos; observamos que estudos dão atenção para reduzir acúmulos dos metabólitos que diminuem a fadiga durante o exercício físico intenso, usando aminoácidos conhecidos por induzir mudanças metabólicas, entre eles a arginina. O presente estudo teve como objetivo estudar o efeito da suplementação aguda de aspartato de arginina em indivíduos sadios treinados submetidos a um protocolo de exaustão em um cicloergômetro. Foram utilizados 12 indivíduos treinados do sexo masculino, idade de 22,6 ± 3,5 anos. Realizaram três testes 90 minutos após a administração em dose única do aspartato de arginina ou solução placebo, em um cicloergômetro, em que incrementos de cargas foram adicionados até a exaustão. Amostras sanguíneas foram obtidas para análises bioquímicas como: creatinina, uréia, glicose e lactato. Diferenças estatísticas não foram encontradas ao comparar os valores de Freqüência Cardíaca Máxima, Tempo Máximo e Carga Máxima e também ao comparar os resultados anteriores e posteriores ao teste para uréia, creatinina e glicose. As concentrações de lactato (mmol/l) apresentaram diferença estatística ao comparar os valores pré-teste (Controle: 2,2 ± 0,14; Arginina: 2,43 ± 0,23; Placebo: 2,26 ± 0,11) com valores pós-teste (Controle 10,35 ± 0,57; Arginina: 12,07 ± 0,88; Placebo: 12,2 ± 0,96), p < 0,001. Os principais resultados deste estudo indicam que a administração aguda de aspartato de arginina não se mostrou efetiva em aumentar a tolerância à fadiga dos indivíduos avaliados e tratados no protocolo de teste incremental até a exaustão. Assim, podemos concluir que a dose utilizada não foi capaz de aumentar a tolerância à fadiga muscular.
Abundance and frugivory of the toco toucan (Ramphastos toco) in a gallery forest in Brazil's Southern Pantanal
Authors: Ragusa-Netto J.
Published: May 2006

Unlike other toucan species, the Toco toucan (Ramphastos toco) - the largest Ramphastidae - usually inhabits dry semi-open areas. This conspicuous canopy frugivore uses a large home range that includes a variety of vegetation types, among which gallery forests are widely cited as important to this species. However, the factors relating to the occurrence of Toco toucans in such habitats are unclear. I studied the abundance of Toco toucans as well as the availability of fleshy fruit in a gallery forest in the southern Pantanal (sub-region of Miranda, Brazil), in order to assess the relationship between these parameters. Also, I examined toucan foraging activity to analyze its relationship with both toucan abundance and fruit availability. The presence of the Toco toucan was more common in the gallery forest from the middle to the end of the dry season and during the middle of the wet season. Toucans foraged for fleshy fruits, mainly Genipa americana, Ficus luschnatiana, and Cecropia pachystachya fruits, feeding mostly on G. americana (by far the favorite food resource) and F. luschnatiana fruits during the dry season, while C. pachystachya fruits were important in the wet season. Toco toucans foraged particularly heavily (> 80% of foraging activity) on G. americana fruits during the latter part of the dry season, when fleshy fruit availability declined sharply. Toco toucan abundance in the gallery forest was associated with the availability of the most commonly consumed fleshy fruits, and also with its foraging activity. This finding suggests that the Toco toucan moved to the gallery forest periodically in response to the availability of abundant food resources, especially the G. americana fruits widely available and exploited during the severely dry season. Therefore, these fruits potentially contribute to Toco toucan persistence in the South Pantanal during the harshest period of the year.
Endarterectomia carotídea sob bloqueio loco-regional
Authors: Guillaumon Ana Terezinha , Oliveira Nara Gelle , Freire Lucas Marcelo Dias , Baldini Neto Luis , Martins Aline Meira , Rocha Eduardo Faccini
Published: May 2006

OBJETIVO: Os autores objetivam descrever os resultados nas cirurgias de endarterectomia carotídea, utilizando-se anestesia loco-regional, emprego seletivo de shunt e proteção farmacológica intra-operatória. MÉTODO: Foram estudados doentes submetidos à endarterectomia carotídea sob bloqueio loco-regional, no Hospital das Clínicas da Universidade Estadual de Campinas (UNICAMP), no período de março de 1996 a maio de 2004. Este estudo é composto de 119 endarterectomias (108 doentes), sendo 69 doentes (63,8%) do sexo masculino e 39 (36,2%) do sexo feminino. A idade média foi de 63 anos, variando entre 43 e 83 anos. A indicação da operação foi estenose sintomática em 60 doentes (55,5%) e assintomática em 48 (44,5%). Foi realizada avaliação, por imagem, pelo eco-Doppler colorido e arteriografia. RESULTADOS: Foram excluídos do trabalho cinco doentes nos quais foi necessária a conversão para a anestesia geral por intolerância à colocação do clampe carotídeo. Dos 103 doentes submetidos a 114 endarterectomias, utilizamos um shunt em quatro cirurgias (3,5%), em função da intolerância do paciente à colocação do clampe carotídeo durante o ato cirúrgico. Utilizou-se remendo em 19 (16,6%) cirurgias. A mortalidade no período pós-operatório imediato ocorreu em três doentes (2,6%), todos em decorrência de acidente vascular cerebral. Um doente (0,87%) apresentou acidente vascular isquêmico menor, e um (0,87%) doente apresentou síndrome de hiperperfusão, que evoluiu com acidente vascular cerebral hemorrágico. Esse doente foi submetido à drenagem do hematoma cerebral, com recuperação total do déficit neurológico. No pós-operatório tardio, houve reestenose ou oclusão em quatro doentes (5,3%). CONCLUSÃO: A endarterectomia carotídea pode ser realizada com segurança no doente em vigília, utilizando-se o shunt seletivamente, com a utilização de fármaco-proteção cerebral. O bom resultado obtido e a baixa morbimortalidade trazem um diferencial no tratamento da doença carotídea.
Doença arterial obstrutiva periférica: que atenção temos dispensado à abordagem clínica dos pacientes?
Authors: Durazzo Anaí Espinelli de Souza , Sitrângulo Jr. Cid José , Presti Calogero , Silva Erasmo Simão da , De Luccia Nelson
Published: May 2006

OBJETIVO: Avaliar como pacientes com doença arterial obstrutiva periférica têm sido tratados, em nosso meio, com relação aos fatores de risco e comorbidades. MÉTODO: Questionário sobre pesquisa e tratamento da dislipidemia, diabetes, exercício, uso de anti-plaquetários, tabagismo e hipertensão arterial no paciente com doença arterial obstrutiva periférica foi aplicado entre os médicos presentes na reunião mensal de março de 2004 da Sociedade Brasileira de Angiologia e Cirurgia Vascular - Regional São Paulo. RESULTADOS: Dos 102 questionários distribuídos, 75 foram respondidos (taxa de resposta de 73,5%). Entre os consultados, 82% pesquisam rotineiramente perfil lipídico e 20% visam alvo de LDL-colesterol abaixo de 100 mg/dl; 94% realizam pesquisa para diabetes melito; 97% recomendam exercício; 79% prescrevem aspirina; 97% aconselham que os pacientes parem de fumar e 60% se restringem ao aconselhamento isoladamente; 18% não realizam a medida da pressão arterial durante a consulta e 19% visam alvo pressórico de 130 x 80 mmHg. Considerando todas as avaliações em conjunto - intervenção no estilo de vida, no sentido de parar de fumar, orientação de exercícios, uso de anti-plaquetários, realização de pesquisa para diabetes melito, controle rigoroso da pressão arterial e lípides - observou-se que 7% dos entrevistados seguem todas essas recomendações como uma rotina estabelecida. CONCLUSÃO: O presente estudo demonstrou que, em nosso meio, a pesquisa e o tratamento dos fatores de risco e comorbidades nos pacientes com doença arterial obstrutiva periférica estão sendo sub-realizados.
Engineering, architecture and the River Po footbridge, Turin
Authors: Mairs D. , Whitby M.
Published: May 2006

This paper traces the changes in the roles of both engineers and architects in bridge design. It argues that, with footbridges, because of the particular challenges these pose, both roles have come together. To illustrate this point, the paper then looks in detail at the River Po Footbridge in Turin, Italy, which was designed by a bridge team that includes both architects and engineers.
Eight footbridges in the Rembrandt Park in Amsterdam
Authors: Smits J.
Published: May 2006

Eight footbridges were erected in the Rembrandt Park in Amsterdam, the Netherlands in 2001. The decks are in weathering steel and the parapets in structural glass and stainless steel. The project involved the design of eight bike and pedestrian bridges to replace their worn-out wooden predecessors. Elegant and light, these are a modern interpretation of the typical nineteenth century park bridge. A CorTen steel bridge deck is embraced by balustrades made from steel and strengthened glass. The balustrades are made from curved and laminated glass panels, which hang from the bridge by stainless steel supports. The stainless steel handrails frame the glass panels above the deck, whilst underneath the bridge the glass hangs free, allowing the free-flow of rainwater.
Effect of Flapless Implant Surgery on Soft Tissue Profile: A Randomized Controlled Clinical Trial
Authors: Oh Tae‐Ju , Shotwell Jeffrey L. , Billy Edward J. , Wang Hom‐Lay
Published: May 2006

Background: Flapless implant surgery has been suggested as one possible treatment option for enhancement of implant esthetics.

Methods: Twenty‐four patients with a missing tooth in the premaxillary region were randomly assigned to one of two groups (12 each): immediate loading (IL) or delayed loading (DL) (loading after 4 months). An endosseous implant was placed in each patient via a flapless surgery. Clinical measurements including the papillary index (PPI) (0, no papilla; 1, less than half; 2, more than half but not complete fill; 3, complete fill; and 4, overfill), marginal levels of the soft tissue (ML), probing depths (PDs), modified bleeding index (mBI), modified plaque index (mPI), and the width of the keratinized mucosa (WKM) were performed at baseline (at the time of loading) and at 2, 4, and 6 months.

Results: The soft tissue profile remained stable up to 6 months, without significant differences between the two groups (mean PPI and ML at 6 months, 2.16 and 0.30 mm, respectively). Mean PPI in the IL group significantly increased from 1.50 at baseline to 2.09 at 2 months, and the significance remained up to 6 months (2.30 at 6 months) (P <0.05), whereas in the DL group, no significant changes were found from baseline to 6 months in mean PPI (2.06 at both time points). Mean PPI increased over time when two treatment groups were combined; however, no statistical significance was found. In ML, the difference at baseline between the two groups (−0.28 mm for DL versus 0.17 mm for IL; P <0.05) was no longer significant at 2 months (0 versus 0.08 mm for DL and IL, respectively) and thereafter (P >0.05). No significant differences were detected between groups at each time and over time in the other clinical parameters, PD, mBI, mPI, and WKM (P >0.05).

Conclusions: The results of this study indicate that creeping attachment (i.e., soft tissue recovery) might occur within 2 months after IL. The study suggests that flapless implant surgery provides esthetic soft tissue results in single‐tooth implants either immediately or delayed loaded. Other long‐term randomized controlled clinical trials with a large sample size and comparison group (i.e., implant surgery with flap) are recommended to verify the conclusions drawn in this preliminary study.
Eosinophilic Granuloma Masquerading as Aggressive Periodontitis
Authors: Silvestros S.S. , Mamalis A.A. , Sklavounou A.D. , Tzerbos F.X. , Rontogianni D.D.
Published: May 2006

Background: Eosinophilic granuloma (EG) is the mildest and mainly localized form of the clinicopathologic spectrum of Langerhans' cell histiocytosis. It is a destructive osseous lesion characterized by a vast number of eosinophils and histiocytes. The etiology remains unknown. In this paper, a case of EG is presented that was initially diagnosed and treated as aggressive periodontitis (AP).

Methods: Despite treatment procedures, the EG continued to expand very quickly, destroying the lingual cortical bone and the neighboring soft tissues and exhibiting periosteal reaction. Diagnosis of EG was established on the basis of histopathologic and immunohistochemical evaluation. Moreover, certain manifestations in the skeletal and respiratory system were observed.

Results: Surgical curettage of the lesions was effective; however, corticosteroids and low‐dose radiation were used as adjunctive therapy.

Conclusion: The rapid progress of eosinophilic granuloma, the diagnostic problems, and the consequences of late diagnosis and treatment are discussed.
Steering (Dis)Course Between Metaphors and Rigor: Using Focal Analysis to Investigate an Emergence of Mathematical Objects
Authors: Sfard Anna
Published: May 2006

This study deals with students' construction of mathematical objects. The basic claim is that the need for communication—any attempt to evoke certain actions by others—is the primary driving force behind all human cognitive processes. Effectiveness of verbal communication is seen as a function of the quality of its focus. Material objects may serve as a basis for creation of such a focus, but in some discourses, focus-engendering objects must be created. Such discursive construction is observed in analysis of one classroom episode. Special attention is given to metaphor, which is the point of departure for the construction process, and to the subsequent dialectical process of closing the gap between the metaphor-induced expectations and the need for a well-defined construction procedure to ensure effective communication.
Language Development and Concept Flexibility in Dyscalculia: A Case Study
Authors: Montis Kristine K.
Published: May 2006

Dyscalculia is a psychological and medical term that refers to extreme difficulty in learning mathematics and to deficits in the production of accurate, efficient arithmetic calculations, in particular. In this article I report on a yearlong qualitative case study of a 12-year-old student who displayed many characteristics of dyscalculia. The results of the study are discussed as they relate to recent medical and learning-disability research. This student's learning experiences during her school mathematics and tutoring sessions demonstrate the vital role language processes play in the development of the concept flexibility necessary for success in mathematics. Outlined in the closing section are implications of this study for pedagogy in classrooms that include mainstreamed students with learning disabilities.
Defects in GaN Nanowires
Authors: Tham D. , Nam C.‐Y. , Fischer J. E.
Published: May 2006

High‐resolution transmission electron microscopy (HRTEM) and cross‐sectional transmission electron microscopy (XTEM) are used to characterize common defects in wurtzite GaN nanowires grown via a vapor–liquid–solid (VLS) mechanism. HRTEM shows that these nanowires contain numerous (001) stacking defects interspersed with small cubic GaN regions. Using XTEM, bicrystalline nanowires are discovered with twofold rotational twin axes along their growth directions, and are found to grow along high‐index directions or vicinal to low‐index planes. We propose a defect‐mediated VLS growth model to qualitatively account for the prevalence of these extended defects, and discuss the implications of these defects for nanowire growth kinetics and device behavior.
Analysis of Host‐Assisted Guest Protonation Exemplified for p‐Sulfonatocalix[4]arene—Towards Enzyme‐Mimetic pKa Shifts
Authors: Bakirci Hüseyin , Koner Apurba L. , Schwarzlose Thomas , Nau Werner M.
Published: May 2006

The pD dependence of the complexation of p‐sulfonatocalix[4]arene (CX4) with the azoalkanes 2,3‐diazabicyclo[2.2.1]hept‐2‐ene (1), 2,3‐diazabicyclo[2.2.2]oct‐2‐ene (2), 2,3‐diazabicyclo[2.2.3]non‐2‐ene (3), and 1‐methyl‐4‐isopropyl‐2,3‐diazabicyclo[2.2.2]oct‐2‐ene (4) in D2O has been studied. The pD‐dependent binding constants, determined by 1H NMR spectroscopy, were analyzed according to a seven‐state model, which included the CX4 tetra‐ and penta‐anions, the protonated and unprotonated forms of the azoalkanes, the corresponding complexes, as well as the complex formed between CX4 and the deuteriated hydronium ion. The variation of the UV absorption spectra, namely the hypsochromic shift in the near‐UV band of the azo chromophore upon protonation, was analyzed according to a four‐state model. Measurements by independent methods demonstrated that complexation by CX4 shifts the pKa values of the guest molecules by around 2 units, thereby establishing a case of host‐assisted guest protonation. The pKa shift can be translated into improved binding (factor of 100) of the protonated guest relative to its unprotonated form as a result of the cation‐receptor properties of CX4. The results are discussed in the context of supramolecular catalytic activity and the pKa shifts induced by different types of macrocyclic hosts are compared.
Regulation of insulin response in skeletal muscle cell by caveolin status
Authors: Oh Yoon Sin , Cho Kyung A. , Ryu Sung Jin , Khil Lee‐Yong , Jun Hee‐Sook , Yoon Ji‐Won , Park Sang Chul
Published: May 2006

Recent studies on the role of caveolin‐1 in adipocytes showed that caveolin has emerged as an important regulatory element in insulin signaling but little is known on its role in skeletal muscle cells. In this study, we demonstrate for the first time that caveolin‐1 plays a crucial role in insulin dependent glucose uptake in skeletal muscle cells. Differentiation of L6 skeletal muscle cells induce the expression of caveolin‐1 and caveolin‐3 with partial colocalization. However in contrast to adipocytes, phosphorylation of insulin receptor β (IRβ) and Akt/Erk was not affected by the respective downregulation of caveolin‐1 or caveolin‐3 in the muscle cells. Moreover, the phosphorylation of IRβ was detected not only in the caveolae but also in the non‐caveolae fractions of the muscle cells despite the interaction of IRβ with caveolin‐1 and caveolin‐3. These data implicate the lack of relationship between caveolins and IRβ pathway in the muscle cells, different from the adipocytes. However, glucose uptake was reduced specifically by downregulation of caveolin‐1, but not that of caveolin‐3. Taken together, these observations suggest that caveolin‐1 plays a crucial role in glucose uptake in differentiated muscle cells and that the regulation of caveolin‐1 expression may be an important mechanism for insulin sensitivity, implying the role of muscle cells for type 2 diabetes. J. Cell. Biochem. 99: 747–758, 2006. © 2006 Wiley‐Liss, Inc.
The electromagnetic effect of cooling fins
Authors: Chiu S. B. , Ding C. H. , Chou J. H.
Published: May 2006

The electromagnetic effect of cooling fins is studied by solving Maxwell equations numerically using a FDTD method under high‐frequency operating conditions. The fin is attached to a square IC chip to form a package. The overall size of the package is 25 mm × 25 mm × 17.5 mm. A smooth compact pulse with a reference frequency of either 1 or 2.5 GHz is used as the excitation source of EM waves. Six fin configurations are investigated. Computational results indicate that a fin can act as an antenna. For the present type of excitation source, resonance could occur roughly at frequencies of 2.5, 5 and 7.5 GHz, depending on the source reference frequency and fin geometries. Thus, fin effects should be considered in the electrical design phase since noises could be induced in the circuit due to the presence of fins. Copyright © 2006 John Wiley & Sons, Ltd.
Interannual variability of the Tropical Atlantic independent of and associated with ENSO: Part II. The South Tropical Atlantic
Authors: Handoh Itsuki C. , Bigg Grant R. , Matthews Adrian J. , Stevens David P.
Published: May 2006

Two dominant ocean–atmosphere modes of variability on interannual timescales were defined in part I of this work, namely, the North Tropical Atlantic (NTA) and South Tropical Atlantic (STA) modes. In this paper we focus on the STA mode that covers the equatorial and sub‐tropical South Atlantic. We show that STA events occurring in conjunction with ENSO have a preference for the southern summer season and seem to be forced by an atmospheric wave train emanating from the central tropical Pacific and travelling via South America, in addition to the more direct ENSO‐induced change in the Walker Circulation. They are lagged by one season from the peak of ENSO. These events show little evidence for other‐than‐localised coupled ocean–atmosphere interaction.

In contrast, STA events occurring in the absence of ENSO favour the southern winter season. They appear to be triggered by a Southern Hemisphere wave train emanating from the Pacific sector, and then exhibit features of a self‐sustaining climate mode in the tropical Atlantic. The southward shift of the inter tropical convergence zone that occurs during the warm phase of such an event triggers an extra tropical wave train that propagates downstream in the Southern Hemisphere. We present a unified view of the NTA and STA modes through our observational analysis of the interannual tropical Atlantic variability. Copyright © 2006 Royal Meteorological Society.