Vols un gen?

En el meu darrer article (AVUI,8 de maig) parlava dels efectes secundaris dels fàrmacs i les teràpies mèdiques, i de les proves que es fan per reduir-ne la incidència, que inclouen assaigs clínics amb voluntaris. Respecte als voluntaris afegia, amb certa ironia, que s'ha de suposar que quan viuen en països del Tercer Món les condicions mèdiques il·legals són iguals que quan els assaigs es fan a Occident, però que malauradament potser en ocasions això era suposar massa [...].

Determinação voltamétrica de metais em águas e fluidos biológicos empregando mineralização de amostras com radiação ultravioleta

This work describes the optimization of pretreatment steps for the destruction of organic matter in samples of waters and biological fluids, by using an UV irradiation system with a high power UV radiation source (400 W). The efficiency of the system constructed for the photo-decomposition of samples of model waters, natural waters and biological fluids was investigated by performing recovery experiments of the metallic species Zn(II), Cd(II), Pb(II), Cu(II), Al(III) and Fe(III). The use of UV irradiation allowed the liberation of metals bound to the organic matrix and the determination of the total content of elements in the samples.

Quantificação simultânea de indicadores biológicos de exposição a solventes orgânicos por cromatografia líquida de alta eficiência

Biological monitoring is very important to guarantee health to workers. This method was developed for simultaneous determination of xylene, toluene, styrene and ethylbenzene metabolites. It involves only dilution and centrifugation of urine samples and improved chromatographic conditions. Analyses show recovery > 95%; r² > 0.99; intermediate precision CV% < 6% and % bias < ±10. Exposed subjects presented at least three metabolites in urine. The method proved to be feasible, reliable and important in biological monitoring, especially in exposure to organic solvent mixtures.

Fonologia catalana

L'objectiu d'aquest llibre és presentar una descripció i una anàlisi sistemàtiques dels fenòmens fonològics del català central, encara que també s'hi trobaran referències a altres varietats dialectals. Per a cada un dels temes de la fonologia del català que es tracten, primer es fa una descripció deis fets. A continuació es presnta una anàlisi del fenomen descrit en el model de la fonologia generativa clàssica, seguint bàsicaament les propostes de Chomsky & Halle (1968), amb la incorporació, però, de l'estructura sil·làbica; en alguns casos es valoren altres possibilitats d'anàlisi dins del matelx model. També s'introdueix, en lletra petita, informaCIO complementària. Apareixen en aquest cos de lletra tant descripcions de diversos dialectes com anàlisis alternatives en el marc de l'estructuralisme (en la línia de les propostes d'Alarcos i de Badia) o en teories generativistes més recents (com la fonologla autosegmental o la fonologia mètrica). En les transcripcions es fan servir sempre els símbols de l'Alfabet Fonètic Internacional (AFI), en la versió del 1993 (corregIda el 1996), que apareix al final d'aquest llibre.

Comparative performance of the stable isotope signatures of carbon, nitrogen and oxygen in assessing early vigour and grain yield in durum wheat

The present paper studied the performance of the stable isotope signatures of carbon (δ13C), nitrogen (δ15N) and oxygen (δ18O) in plants when used to assess early vigour and grain yield (GY) in durum wheat growing under mild and moderate Mediterranean stress conditions. A collection of 114 recombinant inbred lines was grown under rainfed (RF) and supplementary irrigation (IR) conditions. Broad sense heritabilities (H2) for GY and harvest index (HI) were higher under RF conditions than under IR. Broad sense heritabilities for δ13C were always above 0·60, regardless of the plant part studied, with similar values for IR and RF trials. Some of the largest genetic correlations with GY were those shown by the δ13C content of the flag leaf blade and mature grains. Under both water treatments, mature grains showed the highest negative correlations between δ13C and GY across genotypes. Flag leaf δ13C was negatively correlated with GY only under RF conditions. The δ13C in seedlings was negatively correlated, under IR conditions only, with GY but also with early vigour. The sources of variation in early vigour were studied by stepwise analysis using the stable isotope signatures measured in seedlings. The δ13C was able to explain almost 0·20 of this variation under RF, but up to 0·30 under IR. In addition, nitrogen concentration in seedlings accounted for another 0·05 of variation, increasing the amount explained to 0·35. The sources of variation in GY were also studied through stable isotope signatures and biomass of different plant parts: δ13C was always the first parameter to appear in the models for both water conditions, explaining c. 0·20 of the variation. The second parameter (δ15N or N concentration of grain, or biomass at maturity) depended on the water conditions and the plant tissue being analysed. Oxygen isotope composition (δ18O) was only able to explain a small amount of the variation in GY. In this regard, despite the known and previously described value of δ13C as a tool in breeding, δ15N is confirmed as an additional tool in the present study. Oxygen isotope composition does not seem to offer any potential, at least under the conditions of the present study.

Materiais híbridos à base de sílica obtidos pelo método sol-gel

This review deals with silica based hybrid materials obtained by the sol-gel method. It involves concepts, classifications and important definitions regarding the sol-gel method that allows obtaining materials with organic and inorganic components dispersed in a molecular or nanometric level. We discuss the properties and characteristics of hybrid materials related to experimental synthesis conditions. We devote a special attention to the nanostructured materials, where the self-organization is imposed by the organic component. Finally, we present some important applications of these materials based on their specific properties.

Degradação fotocatalítica do fungicida tebuconazole em solução aquosa

The tebuconazole photocatalytic degradation kinetics was studied in a batch reactor using TiO2 (P25-Degussa) as catalyst and a high pressure mercury lamp. The photolysis, adsorption and irradiation effects in the reaction rate were evaluated. Afterward, the suspension catalyst concentration and initial pH to the maximum reaction rate was determined. It was observed that the reaction rate can be approached by a pseudo-first order, with a maximum kinetics constant at 260 mg L-1catalyst concentration and pH 7.7.

Nanotubos de TiO2 dopados com nitrogênio: comparação das atividades fotocatalíticas de materiais obtidos através de diferentes técnicas

TiO2 nanotubes were synthesized by hydrothermal method and doped with three nitrogen compounds to enhance photocatalytic activity under visible light. Catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and specific surface area and pore volume determined by BET and BJH methods, respectively. Photocatalytic activity was evaluated by photodegradation of rhodamine B under visible and UV radiations. Results showed doped-nanotubes were more efficient under visible light. The best photocatalytic activity was for sample NTT-7-600/NH3I, being 30% higher than the non-doped sample.

Síntese, caracterização e atividade fotocatalítica de catalisadores nanoestruturados de TiO2 dopados com metais

Titanium dioxide nanostructured catalysts (nanotubes) doped with different metals (silver, gold, copper, palladium and zinc) were synthesized by the hydrothermal method in order to promote an increase in their photocatalytic activity under visible light. The catalysts were characterized by X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy and specific area and pore volume determination. The materials' photocatalytic activity was evaluated by rhodamine B decomposition in a glass batch reactor. Under UV radiation, only nanotubes doped with palladium were more active than the TiO2 P25, but the samples doped with silver, palladium and gold exhibited better results than the undoped samples under visible light.

A FTIR study of the metal-support interactions and hydrogen spillover on Pd/TiO2 and Ni/TiO2

Nickel and palladium dispersed on titania support were submitted to reductive treatment, under hydrogen, at 200 and 500 ºC. After the reductive thermal treatment the materials were exposed to carbon monoxide (10 Torr) and analyzed in the infrared region. The increasing of the electronic density in the metallic d subshell, produced by the reductive thermal treatment, was monitored by the infrared stretching band shift of carbon monoxide adsorbed and it was interpreted as a consequence of the metal-support interactions. The highest effect was observed for Pd/TiO2 system. From the FTIR spectra was also observed that the hydrogen spillover was stronger on Pd/TiO2 than Ni/TiO2 system.

Clivagem dos ciclopaladados diméricos [Pd(dmba)(m-X)]2 (dmba = N,N-dimetilbenzilamina; X = Cl, N3, NCO) por tiouréia

Ciclopaladados diméricos do tipo [Pd(dmba)(m-X)]2 (dmba = N,N-dimetilbenzilamina; X = Cl, N3, NCO) reagem com tiouréia (tu), à temperatura ambiente, resultando espécies mononucleares do tipo [Pd(dmba)(X)(tu)]. Todos os compostos foram caracterizados por análise elementar, espectroscopias no IV e de RMN de ¹H e com base nessas técnicas as estruturas, desses compostos, foram propostas. Os espectros de absorção no infravermelho mostraram que a coordenação da tiouréia, ao paládio, ocorre através do átomo de enxofre. O anel ciclometalado foi confirmado através da espectroscopia de RMN de ¹H.

Síntese e emprego do [Pd(dmba)(NCO)(PPh3)] em processos catalíticos envolvendo a preparação de derivados da uréia e de alcoxicarbonil complexos

Este trabalho trata do emprego do ciclometalado [Pd(dmba) (NCO)(PPh3)] (dmba = N,N-dimetilbenzilamina; PPh3 = trifenilfosfina) em processos catalíticos em fase homogênea, envolvendo a reação entre p-toluidina e p-nitrotolueno, produzindo N,N'-bis(4-metilfenil)uréia. A reação foi realizada a 140 0C, sob pressão inicial de CO de 60 bar. Empregou-se também o mesmo composto em reações de carbonilação na presença dos álcoois metílico e etílico, obtendo-se os alcoxicarbonil complexos [Pd(NCO)(CO2R)(PPh3)2] (R=Me ou Et). Constatou-se que o emprego do [Pd(dmba)(NCO)(PPh3)] nos referidos processos, propiciou a formação dos produtos com bons rendimentos.

Dite alla giovine

Soitinnus: sopraano, baritoni, orkesteri.

Similaridades entre semiologias na metodologia da aprendizagem baseada em problemas

O Programa de Aprendizagem de Ginecologia e Obstetrícia da PUC-PR adota a aprendizagem baseada em problemas como metodologia de aprendizagem. Neste programa, são executados diversos casos clínicos que compõem seu conteúdo. Para cada caso clínico, os professores definem uma semiologia principal e as respectivas semiologias secundárias, a fim de definir o conjunto de ações ou procedimentos que os alunos devem executar. Visando à inserção das tecnologias da informação e comunicação no aprendizado dos alunos, foi desenvolvido um sistema que permite obter, passo a passo, as ações e procedimentos executados pelos alunos. O objetivo geral deste trabalho é conceber um modelo matemático e computacional que permita obter índices de similaridade entre as semiologias definidas pelos professores e as executadas pelos alunos.

Canine distemper virus detection in asymptomatic and non vaccinated dogs

A quantitative real time polymerase chain reaction (PCR) revealed canine distemper virus presence in peripheral blood samples from asymptomatic and non vaccinated dogs. Samples from eleven domestic dogs with no signs of canine distemper and not vaccinated at the month of collection were used. Canine distemper virus vaccine samples in VERO cells were used as positive controls. RNA was isolated with Trizol®, and treated with a TURBO DNA-free kit. Primers were designed for canine distemper virus nucleocapsid protein coding region fragment amplification (84 bp). Canine b-actin (93 bp) was utilized as the endogenous control for normalization. Quantitative results of real time PCR generated by ABI Prism 7000 SDS Software showed that 54.5% of dogs with asymptomatic canine distemper were positive for canine distemper virus. Dissociation curves confirmed the specificity of the real time PCR fragments. This technique could detect even a few copies of viral RNA and identificate subclinically infected dogs providing accurate diagnosis of this disease at an early stage.