bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Thermolysis of Some 1,2-Dioxetanes
Authors: Kopecky Karl R. , Filby John E. , Mumford Cedric , Lockwood Peter A. , Ding Jan-Yih
Published: May 2006

Treatment of the bromohydroperoxides of 2-methyl-2-butene and ethylidenecyclohexane with cold methanolic base produces trimethyl- and 4-methyl-3,3-pentamethylene-1,2-dioxetane, 3 and 8. Under these conditions the bromo- and iodohydroperoxides of 2,3-dimethyl-2-butene A, 1,2-dimethylcyclohexene B, and Δ9,10-octalin C are converted rapidly to the corresponding allylic hydroperoxides. The reaction in methylene chloride between silver ion and the bromo-and iodohydroperoxides of A and the iodohydroperoxides of B and C produces the corresponding dioxetanes in 20–30% yield: tetramethyl-1,2-dioxetane 11, 3,4-dimethyl-3,4-butano-1,2-dioxetane 15, and 3,4:3,4-dibutano-1,2-dioxetane 23. About 50% of the corresponding allylic hydroperoxides also are formed as are pinacolone, ∼15%, 1-acetyl-1-methylcyclopentane, ∼20%, and Δ9,10-octalin, ∼1%, from the appropriate halohydroperoxides.All the dioxetanes are yellow, thermolyze to give only carbonyl cleavage products, and are luminescent. Reduction of 3 with bisulfite ion produced trimethyloxacyclopropane and with iodide ion 2-methyl-2,3-butanediol. Reduction of 8, 11, 15, and 23 with lithium aluminum hydride at −78° gave good yields of the corresponding diols. Treatment with triphenylphosphine of 11 gave tetramethyloxacyclopropane, of 15, a 1:3 ratio of 2-methylene-1-methylcyclohexanol and 2,3-dimethylcyclohexen-3-ol, and of 23, 10-hydroxy- Δ1,9-octalin.Activation parameters for thermolysis of the dioxetanes are (dioxetane, Ea, kcal/mol, ΔS+, e.u.) 3, 23.5 ± 0.5, −5 ± 2; 11, 25.8 ± 0.5, −2 ± 2; 15, 25.7 ± 0.7, 2 ± 2; 23, 22.7 ± 0.9, −3 ± 3.
Oxidation Of Benzylidene Acetals by Ozone
Authors: Deslongchamps Pierre , Moreau Claude , Fréhel Daniel , Chênevert Robert
Published: May 2006

Oxidation of five-membered ring (1,3-dioxolan) and six-membered ring (1,3-dioxan) benzylidene acetals by ozone are reported.
Thermodynamics of Mixed Electrolyte Solutions
Authors: Sangster James , Lenzi Fabio
Published: May 2006

A general thermodynamic expression has been derived for the deviation Δ from Zdanovskii's rule. Conditions have been deduced under which Δ vanishes, and examples given. For nonzero values of Δ it has been shown by means of an example that Δ may be evaluated in some cases by the introduction of empirical assumptions, such as Harned's rule. The use of Zdanovskii's rule in facilitating the integration of the McKay–Perring equation has been discussed briefly.
Sur l'existence des composés P4Sex(x ≤ 3) et P4Se3−nSn(n = 1,2)
Authors: Monteil Yves , Vincent Henri
Published: May 2006

not available
The Hydrolysis of Cyclic Orthoesters. Stereoelectronic Control in the Cleavage of Hemiorthoester Tetrahedral Intermediates
Authors: Deslongchamps Pierre , Chênevert Robert , Taillefer Roland J. , Moreau Claude , Saunders John K.
Published: May 2006

The synthesis of several cyclic dialkoxy orthoesters is reported. Acid hydrolysis of these orthoesters under kinetically controlled conditions gives the corresponding hydroxy esters only. Conformationally rigid cyclic mixed orthoesters give a hydroxy ester by exclusive loss of the axial alkoxy group. A cyclic orthoester can have nine different gauche conformations. It is shown that they are hydrolyzed through only one gauche conformer. These results bring further experimental evidence that there is a stereoelectronic control in the cleavage of tetrahedral intermediates in the hydrolysis of esters.
Etudes expérimentales et théoriques des déplacements chimiques du carbone-13 en serie isothiazolique
Authors: Faure Robert , Llinas Jean-Richard , Vincent Emile-Jean , Rajzmann Michel
Published: May 2006

During a general n.m.r. study of five-membered heterocycles with two hetero-atoms, we measured the 13C chemical shifts, the vicinal couplings [Formula: see text] and the long range couplings for a series of variously substituted isothiazoles. At that time we were able to compare the effects of the various substituents to the effect of the group of hetero-atoms and to demonstrate the pre dominant influence of dissymmetry of the latter on the values of the observed parameters. Moreover, a comparison with theoretical results based on a CNDO model showed deficiencies which justify the search for a representation better adapted, by the introduction of d orbitals, to the sulfur atom. Studies of CNDO parametrization for third row elements are being undertaken by other means. [Journal translation]
Isomerization of Bicyclic Hydrazine Monoesters to N-Amino-2-pyridone Esters, Precursors to Bicyclic "Isosydnones"
Authors: Mackay Donald , Wong Lichin L.
Published: May 2006

Selective aqueous alkaline hydrolysis of the diazetidine diesters 4 gives the basic monoesters 1 which isomerize quantitatively in trifluoroacetic acid or by refluxing with sodium methoxide in dioxane to the N-aminopyridone esters 2. The bridged pyridazine ester 5a can also be selectively hydrolyzed to the presumed intermediate 10, hydrolysis being accompanied by immediate isomerization to 2a. A common mechanistic pattern is proposed for these isomerizations.Heating of 2 causes loss of alcohol to give the mesoionic "isosydnone" 3, a fairly stable ring system slowly opened by ethanol to 2b and by concentrated alkali to the N-aminopyridone 16a. Oxidation of 16a with lead tetraacetate gives the pyridone 18a.
Lithium Aluminum Hydride Reductive Rearrangement of Allylic Acetals to Vinyl Ethers: A Synthesis of 3-Deoxy Glycals
Authors: Fraser-Reid Bert , Tam Steve Y-K. , Radatus Bruno
Published: May 2006

Carbohydrate allylic acetals (hex-2-enopyranosides) are reductively rearranged to vinyl ethers (3-deoxy glycals) by treatment with lithium aluminium hydride in refluxing ethereal solvents. Under similar conditions, some allylic alcohols are also reductively rearranged to olefins, although the reaction appears to be confined to carbohydrate substrates since the reaction fails with typical carbocyclic allylic alcohols.The results are rationalized by postulating the intermediacy of an oxygen–alane complex, this being formed more readily in the case of an hydroxyl (or ester) rather than an ethereal oxygen. An axial oxygen permits easier achievement of the reactive transition state than an equatorial oxygen. The complex normally leads to an SN2' reductive rearrangement in which the entering hydride and departing oxygen are syn-related. Alternatively, and particularly when the double bond is flanked by an hydroxyl group at one allylic position and a leaving group at the other, an abnormal SN2′ process may occur so that the hydride ion is delivered vicinal and cis to the hydroxyl group, with ejection of the leaving group. The process is at all times stereospecific but not always regiospecific.
Water-soluble Lysine-containing Polypeptides. II. The Interaction of Several Sequential Lysine-Glycine Polypeptides with DNA. A Circular Dichroism Study of DNA Conformation in Annealed Complexes
Authors: Williams Ross E. , Kielland Sandra L.
Published: May 2006

not available
Constantes d'association de quelques éthers de polyéthyléne glycols avec Na+, K+, Cs+et Tl+
Authors: Chaput Gérard , Jeminet Georges , Juillard Jean
Published: May 2006

We report data concerning the association of monovalent cations with some polyethyleneglycol ethers that we have prepared.1:1 association constants KA have been obtained in methyl alcohol at 25 °C using selective glass electrode potentiometric measurements for Na+ and K+ and conductimetric measure ments for Cs+ and Tl+.The values obtained for KA and for the selectivity ratio KA(K+)/KA(Na+) increase with the number of coordinating sites.Replacement of the two methoxy terminal groups in the chain by primary amide or ester groups reduces the complexing properties of the ligand.The stereochemistry of the coordination is discussed in the case of some biphenylic polyethers.
Stereoselectivity in the Reactions of Nitrosopiperidine Carbanions. Steric vs. Stereoelectronic Control
Authors: Fraser Robert R. , Grindley T. Bruce , Passannanti Salvatore
Published: May 2006

The anion of N-nitroso-4-phenylpiperidine reacts with methyl iodide, carbon dioxide, and benzophenone to give solely the axial substitution product. A second methylation of the monomethyl derivative gave the 2,6-diaxial derivative. None of the isomer having trans methyl groups could be detected. This trans isomer dominates over cis by 75:25 at equilibrium. From a consideration of the steric interactions present in these nitrosamines, it can be concluded that they alone cannot explain the observed high stereoselectivity. It is proposed that stereoelectronic control contributes significantly to the exclusive axial attack.
Proton Magnetic Resonance Studies of Dinucleotide Conformation in Aqueous Solution. 2′-Deoxythymidylyl-(3′,5′)-2′-deoxy-3′-thymidylate, d(TpTp)
Authors: Wood Donald J. , Ogilvie Kelvin K. , Hruska Frank E.
Published: May 2006

Proton magnetic resonance studies of 2′-deoxythymidine, its 3′-and 5′-monophosphate, its 3′,5′-diphosphate, and the dimer molecules d(TpT) and d(TpTp) in aqueous solution are de scribed. Spectral analysis yields 1H–1H and 1H–31P coupling constants and 1H chemical shifts which can be discussed in terms of the conformational properties of the nucleoside fragments. An important observation is the apparent phosphate–phosphate interaction in a 3′,5′-diphosphate fragment which stabilizes the gauche-gauche conformation about the C4′—C5′ bond.
Détermination du pouvoir sulfonant des acides disulfurique et chlorosulfurique dans le sulfolane
Authors: Pierens Patrick , Auger Yves , Fischer Jean Claude , Wartel Michel
Published: May 2006

On the basis of potentiometric study of the system[Formula: see text]in sulfolane, the dissociation constant of the reaction [Formula: see text] has been found to be [Formula: see text] assuming that the chlorodisulfate ion is completely dissociated to SO3Cl− and SO3. The equilibrium constants of the reactions[Formula: see text]have been determined on the one hand by complexation of SO3 with H2SO4, and on the other by the difference of acidity between HCl and HSO3Cl. The acidity constant of HSO3Cl (k = 10−4.4) is slightly higher than that of H2S207 (k = 10−5). The sulfonating power of some compounds have been found to follow the order [Formula: see text]
Formation Cross Sections of Iodine and Tellurium Isomers Produced in the Fission of 238U by Protons of Energies 30–85 MeV
Authors: Dikšić M. , Yaffe L.
Published: May 2006

Formation cross sections of isomers of 130I, 132I, 134I, 131Te, and 133Te have been obtained from the fission of natural uranium by protons of energies 30–85 MeV. The high-spin isomer is favored in the production and increase in bombarding energy favors the production of the high-spin isomer. From the isomer ratios values of [Formula: see text] the root-mean-square angular momentum, were obtained. These increase with increasing bombarding energy.
Synthèse de l'aza-1-twistane
Authors: Deslongchamps Pierre , Ruest Luc , Dubé Serge
Published: May 2006

A five-step synthesis of 1-azatwistane starting from the known cis 2-benzoyl-1,2,3,4,4a,7,8,8a-octahydro-6(5)-isoquinolone (7) is reported.
Kinetics and Mechanism of the Oxidation of Benzyl Alcohol and Benzaldehyde by Aqueous Sodium Dichromate
Authors: Lee Donald G. , Spitzer Udo A.
Published: May 2006

A kinetic study of the oxidation of a series of substituted benzyl alcohols and benzaldehydes by neutral aqueous sodium dichromate has been completed. The aldehydes are more resistant to oxidation because the reaction mechanism presumably involves hydration prior to oxidation, and under the conditions employed the extent of this hydration is suppressed. These conclusions are consistent with the activation parameters which indicate that the difference in oxidation rate is due to a more negative entropy of activation for the aldehydes.
Studies of Hindered Rotation in Some Group IV Esters of Dimethylcarbamic and Dimethylthiocarbamic Acids
Authors: Lemire A. E. , Thompson J. C.
Published: May 2006

Activation parameters for hindered rotation about the C—N bond have been obtained for some trimethylgermyl, trimethylplumbyl, and tert-butyl esters of N,N-dimethylcarbamic, N,N-dimethylmonothiocarbamic, and N,N-dimethyldithiocarbamic acids. These are compared with previous results for some group IV esters and general considerations as to factors influencing barriers to rotation are discussed. It was found that the degeneracy of the N-methyl resonances observed in the room or low temperature 1H spectra appeared also to extend to the room temperature 13C spectra. A 'steric' effect was noted on the carbonyl and thiocarbonyl resonances.
Fabrication and Use of High-Speed, Concentric H+- and Ca2+-Selective Microelectrodes Suitable for In Vitro Extracellular Recording
Authors: Fedirko Nataliya , Svichar Nataliya , Chesler Mitchell
Published: May 2006

Ion-selective microelectrodes (ISMs) have been used extensively in neurophysiological studies. ISMs selective for H+ and Ca2+ are notable for their sensitivity and selectivity, but suffer from a slow response time, and susceptibility to noise because of the high electrical resistance of the respective ion exchange cocktails. These drawbacks can be overcome by using a “coaxial” or “concentric” inner micropipette to shunt the bulk of the ion exchanger resistance. This approach was used decades ago to record extracellular [Ca2+] transients in cat cortex, but has not been subsequently used. Here, we describe a method for the rapid fabrication of concentric pH- and Ca2+-selective microelectrodes useful for extracellular studies in brain slices or other work in vitro. Construction was simplified compared with previous implementations, by using commercially available, thin-walled borosilicate glass, drawing an outer barrel with a rapid taper (similar to a patch pipette), and by use of a quick and reliable silanization procedure. Using a piezoelectric stepper to effect a rapid solution change, the response time constants of the concentric pH and Ca2+-electrodes were 14.9 ± 1.3 and 5.3 ± 0.90 ms, respectively. Use of these concentric ISMs is demonstrated in rat hippocampal slices. Activity-dependent, extracellular pH, and [Ca2+] transients are shown to arise two- to threefold faster, and attain amplitudes two- to fourfold greater, when recorded by concentric versus conventional ISMs. The advantage of concentric ISMs for studies of ion transport and ion diffusion is discussed.
Definition and Scope of the Islamic Concept of Sale of Goods
Authors: Zahraa  , Mahmor
Published: May 2006

No Abstract
Responsibility of Limited Liability Companies' Managers under Article 219 of the UAE Companies Law
Authors:   Sinjakli
Published: May 2006

No Abstract
Resposta sorológica de adultos à vacinação contra a rubéola
Authors: Candeias J. A. N. , Rosenburg Cornélio P. , Rácz M. L.
Published: May 2006

Foi estudada a resposta sorológica à vacinação contra a rubéola, por via subcutânea, com a cepa vacinal viva atenuada Wistar RA 27/3, num grupo de 30 professoras da rede municipal de ensino de São Paulo. Foram escolhidos, como participantes do grupo, indivíduos destituídos de imunidade contra a rubéola, tendo as dosagens de anticorpos inibidores da hemaglutinação e fixadores do complemento sido feitas em amostras de soro colhidas 10, 30, 90 e 180 dias após a vacinação. Tanto nas provas de inibição da hemaglutinação, como fixação do complemento, observou-se uma soro-conversão de 96,6%. Não se observaram quaisquer relações vacinais no grupo em estudo.
Reporte de un caso de dracunculosis en un canino en la Provincia de Formosa - Argentina
Authors: Hoyos C.B. , Jara G.A. , Monzon C.M.
Published: May 2006

Se comunica el hallazgo de Dracunculus sp. en un canino proveniente de la localidad de Fontana, Departamento Patiño, Provincia de Formosa, Argentina. El hallazgo constituye el cuarto caso de Dracunculosis registrado en animales en una misma área geográfica de Formosa.
Estudo de recepção de impressos por trabalhadores da construção civil: um debate das relações entre saúde e trabalho
Authors: Kelly-Santos Adriana , Rozemberg Brani
Published: May 2006

Trata-se de um estudo de recepção de mensagens por trabalhadores da construção civil. Utilizamos como mediação os materiais educativos (cartazes, folders e cartilhas) produzidos pelo Ministério da Saúde e Ministério do Trabalho e Emprego. Realizamos dois grupos focais, em dois canteiros de obra no Município do Rio de Janeiro, Brasil, para a análise de quatro materiais educativos; utilizamos análise temática. Apresentamos o ponto de vista dos trabalhadores sobre os temas discutidos nos impressos, classificados em dois núcleos de sentidos: saúde e controle social. Discutimos que os trabalhadores apresentam uma visão ampliada de saúde à medida que inclui os determinantes sociais ao processo saúde-doença. Identificamos a pouca participação dos trabalhadores nas ações de fiscalização dos processos de trabalho, e o desconhecimento das ações de saúde do trabalhador desenvolvidas pelo Ministério da Saúde. Concluímos que a análise de materiais educativos por seus destinatários, representa um lugar privilegiado de negociação de sentidos e de apreensão dos modos de viver de grupos específicos. Sugerimos a realização de atividades educativas que utilizem os impressos como mediação para motivar a problematização do processo saúde-doença.
Avaliação da resistência à corrosão em aço inoxidável martensítico do tipo Cr-Ni em meio marinho sintético simulando atividades em águas profundas
Authors: Mariano Neide Aparecida , Pires Amandio da Cruz , Murolo João Paulo , Kuri Sebastião Elias
Published: May 2006

Esse trabalho estuda a resistência à corrosão do aço inoxidável martensítico fundido em meio marinho sintético saturado com CO2 e também faz uma comparação com solução aerada. A liga foi usada na condição temperada e revenida. A corrosão foi avaliada usando a técnica de polarização potenciodinâmica cíclica. As medidas de polarização foram obtidas em meio marinho sintético com concentrações de cloreto de 20000ppm e 80000ppm na temperatura ambiente. As curvas de polarização cíclica obtidas mostram uma região de passivação definida para as condições adotadas para o ensaio, sendo possível para a identificação dos parâmetros eletroquímicos, o potencial de pite, o potencial de proteção e a susceptibilidade ao pite. Em solução saturada com CO2 e concentração de cloreto de 20000ppm, o potencial de proteção aumentou e a susceptibilidade ao pite diminuiu, em comparação com a solução aerada. Em contraste, os potenciais de pite e de proteção decresceram em solução saturada com CO2 e concentração de cloreto de 80000ppm, indicando que a resistência ao pite é influenciada por um sinergismo entre a concentração de cloreto e a solução saturada com CO2.
Diet and capture of Hypostomus strigaticeps (Siluriformes, Loricariidae) in a small brazilian stream: relationship with limnological aspects
Authors: Cardone I. B. , Lima-Junior S. E. , Goitein R.
Published: May 2006

The purpose of this study is to ascertain whether variations in the limnological parameters of the Corumbataí river resulting from the discharge of a variety of wastes into its waters may be responsible for spatial shifts in the diet and capture of the armored catfish Hypostomus strigaticeps (Regan, 1907). Individuals were collected over a period of two years from two sites with similar physical, albeit distinct limnological characteristics. As a whole, the environmental variables (temperature, pH, dissolved oxygen, electrical conductivity, and total coliforms and fecal coliforms) of the two sites were found to vary significantly. The food items found in the guts of these armored catfish (sediments, diatoms, fungi hyphae, chlorophytes, cyanophytes and non-identified material) ranked differently in samples from the two sites. In the more polluted (site B), diatoms and chlorophytes ranked higher in the diet than in that of individuals caught in the more preserved location (site A). This fact may be related to the greater amount of organic material found at site B, which provides favorable environmental conditions for such algae and, consequently, for algivorous fishes. Even so, fewer fish were captured at site B than at site A, suggesting that although food is more abundant in the more polluted site, its limnological conditions appear, on the whole, to be less beneficial than the conditions at site A.
Chromosomal analysis of Astyanax fasciatus (PISCES, CHARACIDAE) from the Araguari river, Uberlândia, MG, Brazil
Authors: Torres-Mariano A. R. , Morelli S.
Published: May 2006

The genus Astyanax is one of the most numerous of the family Characidae, comprising a large number of similar-shaped species, but displaying innumerable karyotypic variations in its chromosome number and/or structure. The literature describes A. fasciatus populations with diploid chromosome numbers varying from 2n = 45 to 2n = 48. In this study, A. fasciatus specimens captured in the Araguari River (Alto Paraná basin) were cytogenetically characterized, revealing a diploid chromosome number of 2n = 46. The nucleolar organizing regions (NORs), detected with silver nitrate staining, showed a multiple system with two pairs of marked chromosomes. These findings are congruent with those of other studies involving populations of the same species.
Trombose venosa profunda como complicação da escleroterapia química no tratamento de telangiectasias dos membros inferiores
Authors: Paschôa Adilson Ferraz , Hayashida Luciana , Siqueira Marcelo Kurz , van Bellen Bonno
Published: May 2006

Os autores relatam dois casos de escleroterapia de telangiectasias, as quais complicaram com trombose venosa profunda. O primeiro caso foi confirmado por flebografia, e o segundo, por duplex scan. Um paciente, 8 anos após, apresentou uma tromboflebite espontânea de veia safena parva, que resultou em pesquisa de trombofilia positiva para o Fator V Leiden. A outra paciente teve pesquisa de trombofilia negativa. Os relatos de tromboembolismo relacionado à escleroterapia são escassos na literatura. O objetivo do trabalho é alertar para essa possibilidade, valorizando as queixas de dor e edema após a escleroterapia. Havendo suspeita clínica, o duplex scan deve ser realizado.
Blue toe syndrome
Authors: Reis Paulo Eduardo Ocke
Published: May 2006

The authors report the case of a man with blue toe syndrome, who developed bilateral foot ischemia and underwent successful repair of an abdominal aortic aneurysm and associated renal artery stenosis. Blue toe syndrome is characterized by tissue ischemia secondary to embolization of cholesterol crystals or atherothrombotic debris. Microembolization most often occurs in elderly men who undergo an invasive vascular procedure or have an aneurysm.
Enxerto aorto-femoral por via laparoscópica: modelo experimental
Authors: Fusco Pedro E. B. , Marino Hélio L. T. , Natal Silvia R. Bottini , Ducatti Liliana S. S. , Poggetti Renato S. , Kauffman Paulo , Puech-Leão Pedro , Birolini Dario
Published: May 2006

OBJETIVO: Verificar a exeqüibilidade de enxerto aorto-femoral por via laparoscópica. MÉTODO: Operamos porco de 75 kg sob anestesia geral. Empregando a técnica do avental (apron) de Dion, expusemos a aorta por laparoscopia. Brevemente, em decúbito dorsal horizontal, dissecamos um "avental" do peritônio parietal esquerdo. A dissecção prosseguiu com rotação medial do cólon esquerdo. O avental, posteriormente fixo à linha mediana, serviu de anteparo às alças intestinais. Pinçamos a aorta e realizamos enxerto aorto-femoral com o tempo abdominal totalmente laparoscópico. RESULTADO: O enxerto foi realizado com sucesso, e o fluxo sangüíneo na prótese foi demonstrado através da incisão femoral. CONCLUSÃO: O enxerto aorto-femoral experimental laparoscópico é exeqüível através da exposição com a técnica do avental.
Plant Population Density and Maturity Effects on Profitability of Short‐Season Maize Production in the Midsouthern USA
Authors: Popp Michael , Edwards Jeff , Manning Patrick , Purcell Larry C.
Published: May 2006

Maize (Zea mays L.) production in the Midsouthern USA has increased dramatically in recent years, primarily as a function of growing nematode pressure in cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] fields as well as the increasing yield potential of maize hybrids. Traditionally, 112‐ to 120‐d maturity hybrids (full season) have been grown using 76‐cm row spacing at population densities of ≈6 to 8 plants m−2. These hybrids, however, reach the reproductive phase of development during the period of a typical midseason drought. Shorter‐season (<110‐d maturity) hybrids, by contrast, avoid a large portion of this drought and require substantially less irrigation. The yield potentials of short‐season hybrids are similar to those of full‐season hybrids, but they require substantially narrower rows (50 cm) and increased populations (10 to 12 plants m−2). In this report, economic trade‐offs among irrigation, seeding rates, yield potential, and seasonal market price trends for production of short‐season hybrids are evaluated. Shorter‐season hybrids were comparable to longer‐season hybrids in terms of yield potential and partial returns. In general, profit‐maximizing seeding rates were higher for shorter‐season hybrids, and higher seasonal prices were insufficient to offset higher seeding costs and thereby change optimal hybrid choice. While irrigation use was curtailed with shorter‐season hybrids, irrigation savings, at current irrigation costs, were insufficient to offset higher seeding costs. Finally, using a simple decision rule of picking maize hybrid by selecting top‐yielding hybrids is challenged in this study as lower‐yielding hybrids with lower seeding requirements exhibited higher comparative returns than the highest‐yielding hybrids at one of the locations.
Differential inhibition of Wnt‐3a by Sfrp‐1, Sfrp‐2, and Sfrp‐3
Authors: Galli Lisa M. , Barnes Tiffany , Cheng Tina , Acosta Lisa , Anglade Adolph , Willert Karl , Nusse Roel , Burrus Laura W.
Published: May 2006

Hamburger Hamilton stage 13 chick embryo was electroporated with constructs encoding Sfrp‐2 (marked by expression of nuclear GFP) and Wnt‐3a (marked by expression of membrane bound GFP) and then incubated until stage 21. A transverse section was then immunostained for Pax‐7 (blue) and antiphosphohistone H3 (red). The upper left panel shows the original image, while the other three panels show digitally manipulated versions of the original image. See Galli et al., Developmental Dynamics 235:681–690. © 2006 Wiley‐Liss, Inc.
Impaired maturation and function of dendritic cells by mycobacteria through IL‐1β
Authors: Makino Masahiko , Maeda Yumi , Mukai Tetsu , Kaufmann Stefan H. E.
Published: May 2006

Dendritic cells (DC) are pivotal for initiation and regulation of innate and adaptive immune responses evoked by vaccination and natural infection. After infection, mycobacterial pathogens first encounter monocytes, which produce pro‐inflammatory cytokines, including IL‐1β, TNF‐α and IL‐6. The role of these cytokines in DC maturation remains incompletely understood. Here, we show that maturation of DC from monocytes was impaired by pretreatment of monocytes with low doses of IL‐1β. Under these conditions, Mycobacterium leprae‐infected DC failed to stimulate antigen‐specific T cell responses. Expression of CD86 and CD83 and production of IL‐12 in response to lipopolysaccharide and peptidoglycan were diminished. In contrast, these DC functions were not impaired by pretreatment with TNF‐α, IL‐6 or IL‐10. When monocytes were infected with M. bovis Bacillus Calmette‐Guérin, and subsequently differentiated to DC, the activity of these DC was suppressed as well. Thus, IL‐1β acts at early stages of differentiation of DC and impairs biological functions of DC at later stages. Therefore, production of IL‐1β by mycobacteria‐infected antigen‐presenting cells counteracts effective stimulation of innate and adaptive immune responses.
Drosophila S2 cells produce multiple forms of carboxypeptidase D with different intracellular distributions
Authors: Kalinina Elena , Fontenele‐Neto Jose D. , Fricker Lloyd D.
Published: May 2006

Carboxypeptidase D (CPD) functions in the processing of proteins that transit the secretory pathway, and is present in all vertebrates examined as well as Drosophila. Several forms of CPD mRNA were previously found in Drosophila that resulted from differential splicing of the gene. In the present study, Northern blot, reverse transcriptase PCR, and Western blot analysis showed that each splice variant occurs in a single cell type, the Drosophila‐derived Schneider 2 (S2) cell line. The short forms containing a single carboxypeptidase domain were secreted from the S2 cells while the long forms containing three carboxypeptidase domains, a transmembrane domain, and one of two different cytosolic tails were retained in the cell. To investigate the role of the two different C‐terminal tail sequences (tail‐1 and tail‐2) that result from the differential splicing within exon 8, constructs containing a reporter protein (albumin) attached to the transmembrane domain and tail‐1 or tail‐2 of CPD were expressed in S2 cells and a mouse pituitary cell line (AtT20 cells). Immunofluorescence analysis revealed different intracellular distributions of the two constructs, with the tail‐2 construct showing considerable overlap with a Golgi marker. The two C‐terminal tail sequences also resulted in different internalization efficiencies from the cell surface in both cell lines. Interestingly, the distribution and routing of the tail‐2 form of Drosophila CPD in the AtT20 cells are similar to the previously characterized endogenous mouse CPD protein, indicating that the elements for this trafficking have been conserved between Drosophila and mammals. J. Cell. Biochem. 99: 770–783, 2006. © 2006 Wiley‐Liss, Inc.
Transverse quadruple systems with five holes
Authors: Keranen M. S. , Kreher D. L.
Published: May 2006

Transverse Steiner quadruple systems with five holes are either of type g5 or g4u1. We concentrate on the systems of type g4u1 and settle existence except when g ≡ u ≡ 2 (mod 4) and all except 40 parameter situations when g ≡ u + 2 ≡ 0 (mod 4). The question of existence for transverse quadruple systems of type g4u1 with index λ > 1 is completely solved for all λ ≥ 13 and λ ∈ {4, 6, 8, 9, 10, 12}. © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 315–340, 2007
Workload management in occupational therapy: the approach taken at University Hospital Nijmegen, St Radboud
Authors: Kuyk‐Minis Marie‐Antoinette H. Van , Madill Helen M.
Published: May 2006

The board of University Hospital Nijmegen stipulates the roles and responsibilities of allied health professionals. It is expected that members of these disciplines will engage in teaching and applied research that will ultimately develop a solid empirical base for their clinical services. This paper outlines the process and outcome of a study of occupational therapists' workload and time management at University Hospital Nijmegen. It describes how members of the Department of Occupational Therapy established their research and teaching priorities, and agreed on a strategy to implement them. Enabling one or two therapists at a time to devote substantial amounts of time to a special task is much more fruitful than trying to split time among many people. A policy and detailed activity plan proved to be a good way of monitoring the output of the department. Copyright © 1997 Whurr Publishers Ltd.
Experiments on spin-up and spin-down on a β-plane
Authors: Jillians W. J. , Maxworthy T.
Published: May 2006

Here we study the spin-up and spin-down of a homogeneous fluid with a free surface on an experimental ‘β-plane’ and describe the important features for both cases over a range of parameters. Quantitative values are found for the velocity fields using a new image processing technique that analyses a video record of particle motion and stores the results digitally. Streamlines, pressure fields and vorticity values are found by interpolation techniques and result in a complete description of the flow characteristics. We discuss the relationship between the results of these experiments and those observed in large-scale homogeneous models of ocean circulation, e.g. Moore (1963). This study extends the work of van Heijst et al. (1990) to the case of spin-up in a rectangular container but of non-uniform depth and we note the differences to and similarities with their observations. It is related, also, to more recent results of Maas et al. (1992), who considered spin-up on a β-plane but in a tank of very different proportions to the one considered here.
Polymorphism of intron 4 in HLA‐A, ‐B and ‐C genes
Authors: Swelsen W.T.N. , Voorter C.E.M. , Van Den Berg‐Loonen E.M.
Published: May 2006

Abstract:  The sequence database of HLA class I genes focuses on the coding sequences, the exons. Limited information is available on the non‐coding sequences of the different class I alleles. In this study we have determined the intron 4 nucleotide sequence of at least one representative of each major allelic group of HLA‐A, ‐B and ‐C. The intron 4 sequences were determined for 27 HLA‐A, 81 HLA‐B and 30 HLA‐C alleles by allele‐specific sequencing, using primers located in adjacent exons and introns. The sequences revealed that the length of intron 4 varies with a minimum of 93 and a maximum of 124 nucleotides as a result of insertions and deletions. There were remarkable similarities and differences within HLA‐A, ‐B and ‐C, as well as between them. Within HLA‐A, a deletion of three nucleotides was detected in several HLA‐A alleles. The HLA‐B alleles could be divided into two groups with one group having a deletion of 11 nucleotides compared with the second group. Within HLA‐C, all Cw*07 alleles showed remarkable differences with the other Cw alleles. Cw*07 had an insertion of three nucleotides, shared only by the Cw*17 group. Moreover, Cw*07 was found to have an aberrant nucleotide sequence. Differences between HLA‐A, ‐B and ‐C alleles were also observed. Remarkable was the deletion of 20 nucleotides in all HLA‐A and ‐B alleles compared with HLA‐C, whereas the HLA‐A alleles showed an insertion of one nucleotide and a deletion of three nucleotides compared with HLA‐B and ‐C. Furthermore, 32 different polymorphic positions were detected between HLA‐A, ‐B and ‐C.
Elimination of damaged proteins during differentiation of embryonic stem cells
Authors: Hernebring Malin , Brolén Gabriella , Aguilaniu Hugo , Semb Henrik , Nyström Thomas
Published: May 2006

During mammalian aging, cellular proteins become increasingly damaged: for example, by carbonylation and formation of advanced glycation end products (AGEs). The means to ensure that offspring are born without such damage are unknown. Unexpectedly, we found that undifferentiated mouse ES cells contain high levels of both carbonyls and AGEs. The damaged proteins, identified as chaperones and proteins of the cytoskeleton, are the main targets for protein oxidation in aged tissues. However, the mouse ES cells rid themselves of such damage upon differentiation
in vitro
. This elimination of damaged proteins coincides with a considerably elevated activity of the 20S proteasome. Moreover, damaged proteins were primarily observed in the inner cell mass of blastocysts, whereas the cells that had embarked on differentiation into the trophectoderm displayed drastically reduced levels of protein damage. Thus, the elimination of protein damage occurs also during normal embryonic development
in vivo
. This clear-out of damaged proteins may be a part of a previously unknown rejuvenation process at the protein level that occurs at a distinct stage during early embryonic development.
The sulfur acclimation SAC3 kinase is required for chloroplast transcriptional repression under sulfur limitation in
Chlamydomonas reinhardtii
Authors: Irihimovitch Vered , Stern David B.
Published: May 2006

Sulfur (S) deprivation responses have been studied extensively in algae and land plants; however, little is known of the signals that link perception of S status to chloroplast gene expression. Here, we have compared the chloroplast S limitation response in WT vs.
sac1
and
sac3
sulfur acclimation mutants of the green alga
Chlamydomonas reinhardtii
. We provide evidence that in the WT, chloroplast transcriptional activity rapidly decreases after removal of S from the medium, leading to reduced transcript accumulation. This decrease correlates with reduced abundance of a σ
70
-like factor, Sig1, which is most likely the unique chloroplast transcription specificity factor. We further show that reduced transcription activity and diminished Sig1 accumulation are mediated by the
SAC3
gene product, a putative Snf1-type Ser/Thr kinase previously shown to have both positive and negative effects on nuclear gene expression. Inclusion of the protein kinase inhibitor 6-dimethylaminopurine during S limitation yielded a pattern of expression that was largely similar to that seen in the
sac3
mutant, lending support to the hypothesis that Sac3 kinase activation leads to transcriptional repression and Sig1 proteolysis. The finding that Sac3 regulates chloroplast gene expression suggests that it has a previously unknown role in integrating the S limitation response in multiple subcellular compartments.
Birth of a chimeric primate gene by capture of the transposase gene from a mobile element
Authors: Cordaux Richard , Udit Swalpa , Batzer Mark A. , Feschotte Cédric
Published: May 2006

The emergence of new genes and functions is of central importance to the evolution of species. The contribution of various types of duplications to genetic innovation has been extensively investigated. Less understood is the creation of new genes by recycling of coding material from selfish mobile genetic elements. To investigate this process, we reconstructed the evolutionary history of
SETMAR
, a new primate chimeric gene resulting from fusion of a
SET
histone methyltransferase gene to the transposase gene of a mobile element. We show that the transposase gene was recruited as part of
SETMAR
40–58 million years ago, after the insertion of an
Hsmar1
transposon downstream of a preexisting
SET
gene, followed by the
de novo
exonization of previously noncoding sequence and the creation of a new intron. The original structure of the fusion gene is conserved in all anthropoid lineages, but only the N-terminal half of the transposase is evolving under strong purifying selection.
In vitro
assays show that this region contains a DNA-binding domain that has preserved its ancestral binding specificity for a 19-bp motif located within the terminal-inverted repeats of
Hsmar1
transposons and their derivatives. The presence of these transposons in the human genome constitutes a potential reservoir of ≈1,500 perfect or nearly perfect SETMAR-binding sites. Our results not only provide insight into the conditions required for a successful gene fusion, but they also suggest a mechanism by which the circuitry underlying complex regulatory networks may be rapidly established.
Dynamic Regulation of Caveolin-1 Trafficking in the Germ Line and Embryo ofCaenorhabditis elegans
Authors: Sato Ken , Sato Miyuki , Audhya Anjon , Oegema Karen , Schweinsberg Peter , Grant Barth D.
Published: May 2006

Caveolin is the major protein component required for the formation of caveolae on the plasma membrane. Here we show that trafficking of Caenorhabditis elegans caveolin-1 (CAV-1) is dynamically regulated during development of the germ line and embryo. In oocytes a CAV-1-green fluorescent protein (GFP) fusion protein is found on the plasma membrane and in large vesicles (CAV-1 bodies). After ovulation and fertilization the CAV-1 bodies fuse with the plasma membrane in a manner reminiscent of cortical granule exocytosis as described in other species. Fusion of CAV-1 bodies with the plasma membrane appears to be regulated by the advancing cell cycle, and not fertilization per se, because fusion can proceed in spe-9 fertilization mutants but is blocked by RNA interference–mediated knockdown of an anaphase-promoting complex component (EMB-27). After exocytosis, most CAV-1-GFP is rapidly endocytosed and degraded within one cell cycle. CAV-1 bodies in oocytes appear to be produced by the Golgi apparatus in an ARF-1–dependent, clathrin-independent, mechanism. Conversely endocytosis and degradation of CAV-1-GFP in embryos requires clathrin, dynamin, and RAB-5. Our results demonstrate that the distribution of CAV-1 is highly dynamic during development and provides new insights into the sorting mechanisms that regulate CAV-1 localization.
Acute alcohol use and the risk of non‐fatal injury in sixteen countries
Authors: Borges Guilherme , Cherpitel Cheryl J. , Orozco Ricardo , Bond Jason , Ye Yu , Macdonald Scott , Giesbrecht Norman , Stockwell Tim , Cremonte Mariana , Moskalewicz Jacek , Swiatkiewicz Grazyna , Poznyak Vladimir
Published: May 2006

Aims  To determine the relative risk (RR) of non‐fatal injury associated with alcohol consumption in a series of emergency departments (EDs), possible effect modifiers and the impact of contextual variables on differences across sites.

Design  The case–crossover method was used to obtain RR estimates of the effect of alcohol on non‐fatal injuries. Meta‐analysis was used to evaluate the consistency and magnitude of RR across sites, and the extent to which contextual variables explain differences in effect sizes.

Participants  Probability samples of 11 536 injured patients attending 28 EDs studies in 16 countries (1984–2002). The majority of the sample was male (65%) and > 30 years old (53%).

Measurements  Exposed cases where those that consumed alcohol 6 hours prior to the injury. Usual alcohol consumption served as the control period.

Findings  Drinking within 6 hours prior to the injury was reported by 21% of the sample. The estimated (random) pooled relative risk for patients who reported alcohol use within 6 hours prior to injury was 5.69 (95% confidence interval = 4.04–8.00), ranging from 1.05 in Canada to 35.00 in South Africa. Effect size was not homogeneous across studies, as societies with riskier consumption patterns had a higher relative risk for injury. Heavier drinkers also showed lower RR.

Conclusions  Acute alcohol was a risk factor for non‐fatal injuries in most sites. Policy measures addressed to the general population are recommended, especially in societies with riskier consumption patterns.
Fracture of ProFile nickel–titanium rotary instruments: a laboratory simulation assessment
Authors: Di Fiore P. M. , Genov K. I. , Komaroff E. , Dasanayake A. P. , Lin L.
Published: May 2006

Aim  To determine the incidence of ProFile nickel–titanium rotary instrument fracture in an endodontic laboratory simulation.

Methodology  Three hundred and sixty dental students used 2880 ProFile nickel–titanium rotary instruments to prepare 1440 simulated root canals in 720 plastic teeth, and another 2880 ProFile nickel–titanium rotary instruments to prepare 1440 natural root canals in 720 extracted teeth. A standardized crown‐down rotary instrumentation technique was used, which included measures to prevent fracture. Rotary instrument fracture was monitored during and after completion of the laboratory simulation exercises to determine the incidence of fracture. When fracture occurred, data were collected concerning the size of the instrument, the length of the instrument fragment, the location of the fragment in the canal and the curvature of the canal in which the instrument fractured.

Results  The incidence of instrument fracture was 0.41% in plastic simulated canals and 0.31% in natural root canals. The overall incidence of instrument fracture was 0.36%. Of the instruments that fractured 67% were size 25, 0.04 taper; and 81% of the fragments were located in the apical third of the canal. The mean, median and mode of the fragment lengths were all 3 mm.

Conclusions  The low overall incidence of fracture in this study suggests that ProFile rotary instruments are safe for use by dental students in laboratory simulations and that if preventive measures are taken the incidence of instrument fracture can be minimized.
The theory‐theory gap: the challenge for nurse teachers
Authors: Dale Andrea E
Published: May 2006

The paper begins with a review of the nature of theory‐based practice and how it is evidenced This is then used to demonstrate that theory is based upon practice and that there is not a gap between theory and practice but rather there is a theory‐theory gap which is evidenced by a lack of experiential knowledge The paper continues by exploring ways in which theory can be integrated in practice to provide the student with experiential knowledge and the challenge this creates for nurse teachers It finishes with a proposal for the way in which the nurse teacher might develop his/her clinical role to address the gap whilst securing their basis for the future in higher education
Good nurse, bad nurse…
Authors: Alavi Christine , Cattoni Jan
Published: May 2006

The construction of the nursing subject is discussed The paper takes a historical perspective, arguing that the range of speaking positions available to the nurse is limited by gender, class and education It evaluates the position of nursing in the university, showing how this also has the propensity to limit the development of the nursing profession
A review of the health promotion and health beliefs of traditional and Project 2000 student nurses
Authors: Mitchinson Susan
Published: May 2006

In this study it was proposed that a more rigorous theoretical component in nursing education courses would produce a nurse who was a proficient health educator and promotor of health A sound knowledge base will enable the student to develop positive attitudes and beliefs towards promoting health and providing health education as a part of nursing practice To test this hypothesis, two groups of students were asked to complete a questionnaire and the answers subsequently compared The results and data analysis supported the hypothesis only in a limited way and a further study on a larger group of students would provide greater insight into the question
Preparing the practitioner for advanced academic study: the development of critical thinking
Authors: Girot Elizabeth Anne
Published: May 2006

Using an evaluative approach, this paper explores the concept of critical thinking and its development within a recently revised study skills programme, preparing practitioners for the academic post‐registration courses in one college of health The current and almost explosive move of nurse education in the United Kingdom into the halls of higher education seems to recognize the need for higher‐order thinking skills in preparation for the unpredictability of nursing practice Using a quasi‐experimental design, the qualitative data analysed from two groups of students who undertook the study skills programme were measured against a control group of students undertaking the same short professional development course through the more traditional university approach of 2 years part‐time academic study The findings acknowledge that the development of critical thinking needs time and exposure to others seeking similar goals In addition, to encourage the process of critical thought, study skills applied to content should be offered, as well as attention to teaching/learning strategies If higher education means a change in culture, of attitude towards learning, then a more comprehensive foundation programme may better commence this process It is anticipated that through such a programme current practitioners may be enabled to achieve successfully within the new academic courses and ultimately be better equipped for the complex decision‐making in practice