Organosilicon compounds as potential wood protecting agents

Wood is very diverse and has specific features making it easily distinguishable from other materials. Due to its properties it can be applied both inside and outside, making it a rewarding material to work with. However, when applied outside it is liable to weathering, inducing changes to the wood, like i.e. surface discolouration, dimensional changes or even wood rot, which are not appreciated by end-users. Therefore wood constructors are looking for protection methods of wood, leading to longer service life of their wood products. Since pressure is put on traditional wood preservation due to environmental and health considerations, new treatment technologies aiming at improved wood properties are launched. Besides wood modification technologies, treatments with organosilicon compounds were proposed. These chemicals proved to be suitable for the protection of other building materials like concrete and might therefore also be suited for wood. To be able to optimise the treatment process and perform quality control afterwards, detection techniques of organosilicons in treated wood could be very helpful. Visualisation combining several scanning techniques proved to be suitable for this purpose and with new, more precise technologies being developed, the possibilities will only grow. However, before quantitative determination will be useful for these purposes obstacles related to the accuracy of the chemical analysis need to be overcome. Since fungal attack is of major concern for the performance of a specific element, research was done to determine the fungal resistance of organosilicon treated wood and on methodology how to properly interpret the results. Furthermore care must be taken with the ecotoxicological consequences of the applied products. Therefore a study was devoted to developing a methodology determining on one hand the fungal efficacy of a certain treatment, while on the other hand the impact to the environment of this treatment was estimated. It was found that improving one parameter was often at the expense of the other parameter. Addition of a biocide improved fungal resistance, but increased the ecotoxicological risk of the leachates of the treated wood. Organosilicons are known as water repellents and are assumed to interfere in the wood-water relationship. Whatever laboratory test performed, this assumption could not be corroborated when organosilicons were applied at concentrations supposed to be economically feasible. When evaluating high retentions to the envelope of the material, better performance was achieved and this both for solid wood and plywood. However, the efficacy was reduced due to weathering. It can be stated that none of the laboratory tests was very hopeful for the application of organosilicons at economically feasible concentrations for wood used outdoors, out of ground contact. It was also demonstrated several times that the standard evaluation methods available are not really suitable for the evaluation of newly developed wood treatments. Therefore small-scaled wooden elements were constructed and exposed to accelerated natural weathering. This time organosilicon impregnated wood behaved much better than the untreated Scots pine sapwood reference material. Due to the treatment fungal discolouration, mass loss and moisture content could be reduced, without the application of a biocide. Further adding a biocide enhanced the first two parameters. Concluding it can be said that organosilicons seem to have certain potential in improving wood characteristics like moisture balance and fungal resistance, as shown in field experiments. Nevertheless it remains doubtful whether that will be sufficient to protect wood in the long term. It is more likely that organosilicons will become one of the components in a more complex formulation than that they will be applied on their own

Preventive action of organosilicon treatments against disfigurement of wood under laboratory and outdoor conditions

A

Ecotoxicity and fungal deterioration of recycled polypropylene/wood composites: Effect of wood content and coupling

Polypropylene (PP)/wood composites were produced by homogenization in a twin-screw extruder and injection molding of tensile bars. Their mechanical properties were determined before and after exposure to biological treatment, and the effect of the treatment was assessed by various ways including visual inspection and the measurement of weight loss. The ecotoxicity of the materials was also evaluated by using the bioluminescent bacteria Vibrio fischeri. The results proved that wood facilitates biodeterioration (colonization) under the conditions used. The coupling agents do not have inhibitory effect, but seems to stimulate fungal growth (biodeterioration) at large loads of wood flour. PP/wood composites can be considered quite durable, but the influence of wood content on environmental resistance must be taken into account for materials intended for applications requiring long-term outdoor exposure as the time of exposure to microbial colonization increases. Direct ecotoxic effect on aquatic ecosystems cannot be expected from PP/wood composites

Methodology to assess both the efficacy and ecotoxicology of preservative-treated and modified wood

Wood used in outdoor conditions out of ground contact is susceptible to weathering, inducing both fungal decay and leaching of components to the environment. This paper presents a methodology to determine these two parameters for untreated, preservative-treated and modified wood. Therefore, the wood was first leached and subsequently exposed to fungal decay of the most prominent wood-rotting fungi. The crustacean Daphnia magna was exposed to the leachates to provide information on their impact on the environment. Combining both parameters reveals that preservative-treated wood and modified wood are capable of protecting the wood adequately for application under use class 3 conditions without posing a threat to the environment. This proves the suitability of the concept of combining efficacy and ecotoxicology for the evaluation of new types of wood treatments

Memórias de Leitura de Pessoas Idosas

Este trabalho consta de uma investigação sobre as memórias de leitura de pessoas idosas. Tem por objetivo resgatar as memórias de leitura dessas pessoas, através dos seus relatos orais, método que nos permite trazer à tona o processo já vivido, oportunizande a desconstrução de imagens prontas, instituídas socialmente. Com este estudo, procuramos responder às seguintes perguntas: Como sedava a prática da leitura no Maranhão, entre os nascidos nas décadas de 1920 a 1950? Como era a relação das pessoas com o livro? Havia facilidade de acesso à biblioteca? Os materiais de leitura eram obtidos através de empréstimo entre amigos e familiares, ou compras? Para resgatar pontos marcantes da história cultural da leitura, contamos com a abonação dos estudos de Bosi (1994); Certeau (1972); Chartier (1998;1996); Halbwachs (1990); Le Goff (1994); Manguel (1997), entre outros que serviram para a construção teórica desta pesquisa. Assim, com este estudo, nas circunstâncias dos relatos orais, constatamos que o processo histórico da leitura resulta do registro da memória, divulgado nas relações sociais, através de um constante exercícioda leitura. Nessa perspectiva, é válido dizer que se muitas pessoas não lêem, é porque não houve, em suas memórias, o registro da necessidade da leitura para a sua própria vida.Palavras-chave: Leitura. Idoso. Maranhão

Sodium, renin, aldosterone, catecholamines, and blood pressure in diabetes mellitus

Sodium, renin, aldosterone, catecholamines, and blood pressure in diabetes mellitus. Interrelations among plasma renin activity (PRA), aldosterone and Cortisol levels, blood volume, exchangeable sodium, urinary catecholamines, and blood pressure were studied in 35 normal subjects and 60 age-matched non-azotemic patients with diabetes mellitus (60% with hypertension, 15% with orthostatic hypotension). Basal PRA, plasma aldosterone, cortisol, blood volume, plasma potassium, and urinary electrolytes were comparable in diabetic and normal subjects. Diabetic patients, however, had a 10% increase in body sodium (P < 0.01), and 8% of them showed normal postural PRA responses and subnormal aldosterone responses; 22% had subnormal PRA and normal aldosterone responses, and 17% had subnormal responses of PRA and aldosterone. Non-PRA-related aldosterone responses could not be explained by ACTH or electrolytes. Orthostatic decreases in blood pressure correlated (P < 0.01) with both catecholamine excretion and basal PRA. This suggests that in diabetes mellitus, body sodium is increased. Basal PRA and plasma aldosterone are usually normal, but their postural responses are frequently impaired. Absent aldosterone responses, despite normal PRA responsiveness, may reflect an adrenal abnormality or an ineffective form of renin. Marked postural aldosterone stimulation, unrelated to PRA, ACTH, or electrolytes, points to a potent unknown factor in aldosterone control. Low levels of free peripheral catecholamines and PRA may be complementary factors contributing to postural hypotension.Sodium, rénine, aldostérone, catécholamines et pression artérielle dans le diabèté sucré. Les inter-relations entre l'activité rénine plasmatique (PRA), les concentrations d'aldostérone et de cortisol, le volume sanguin, le sodium échangeable, les catécholamines urinaires et la pression artérielle ont été étudiées chez 35 sujets normaux et 60 malades atteints de diabété, sans insuffisance rénale et dont les âges étaient appariés (60% avaient une hypertension et 15% une hypotension orthostatique). La PRA de base, l'aldostérone et le Cortisol plasmatiques, le volume sanguin, le potassium plasmatique et les électrolytes urinaires étaient comparables chez les diabétiques et les sujets normaux. Les malades diabétiques, cependant, ont une augmentation de 10% de leur sodium corporel (P < 0,01). Huit pour cent d'entre eux ont une réponse posturale de PRA normale et une réponse de l'aldostérone inférieure à la normale, 22% ont une réponse de PRA inférieure à la normale et une reponse de l'aldosterone normale, et 17% ont des réponses de PRA et de l'aldostérone inférieures à la normale. Les réponses de l'aldostérone sans rapport avec PRA ne peuvent pas être expliquées par l'ACTH ou les électrolytes. Les diminutions de la pression artérielle liées à l'orthostatisme sont correlées (P < 0,01) à la fois avec l'excrétion de catécholamines et la PRA de base. Ceci suggére qu'au cours du diabéte le sodium corporel est augmenté. La PRA et l'aldosterone de base sont souvent normales mais leur réponse posturale est souvent modifiée. L'absence de réponse de l'aldosterone malgré une réponse normale de PRA peut traduire une anomalie surrénale ou une forme de rénine inefficace. Une stimulation posturale importante de l'aldostérone non expliquée par la PRA, l'ACTH ou les électrolytes oriente vers un facteur inconnu mais puissant du contrôle de la sécrétion d'aldostérone. Des concentrations basses de catécholamines libres et une PRA basse peuvent être des facteurs complémentaires qui participent à l'hypotension posturale

Nós, de Salim Miguel: mediações de leitura no Ensino Médio

In this paper, it is discussed how High School students relate to literature books when their mediation prioritizes the aesthetic and artistic experience. This was an intervention research of qualitative approach, whose data collection instrument were narratives written by the students, produced during a focus group, analyzed according to Barthes’s (1997) reversibility approach. As results, it is pointed out that the students’ narratives showed that that literature reading took place as an aesthetic experience and the teaching of literature in High School, when making use of the lists of books to be read in the university entrance exam, can be through fruition.En este artículo, se discute como los estudiantes se relacionan con obras literarias cuando su mediación prioriza la experiencia estética y artística. Fue una investigación-intervención de enfoque cualitativo, cuyo instrumento de coleta de datos fueron narrativas escritas por los estudiantes, producidas durante grupo focal, analizadas según el enfoque de reversibilidad de Barthes (1997). Como resultados, se señala que las narrativas de los alumnos evidenciaron que la lectura de lo literario se dio como experiencia estética y que la enseñanza de la literatura en la Educación Secundaria, al hacer uso de las listas de libros a ser leídos en el examen de selectividad, se puede dar por la fruición.Neste artigo, discute-se como estudantes se relacionam com obras literárias quando sua mediação prioriza a experiência estética e artística. Foi uma pesquisa-intervenção de abordagem qualitativa, cujo instrumento de coleta de dados foram narrativas escritas pelos estudantes, produzidas durante um grupo focal, analisadas segundo a abordagem da reversibilidade de Barthes (1997). Como resultados, sinaliza-se que as narrativas dos alunos evidenciaram que a leitura do literário se deu como experiência estética e que o ensino da literatura no Ensino Médio, ao fazer uso das listas de livros a serem lidos no exame do Vestibular, pode dar-se pela fruição. 

40 Years from Education as the Practice of Freedom: New Perspectives on Paulo Freire from Latin America

The year 2007 marks the 40th anniversary of the original publication in Portuguese of Paulo Freire’s first book, Education as the Practice of Freedom. In honor of this anniversary, this symposium brings together Latin American pedagogues to discuss the development and continued relevance of Freire’s work

Sodium, renin, aldosterone, catecholamines, and blood pressure in diabetes mellitus

Sodium, renin, aldosterone, catecholamines, and blood pressure in diabetes mellitus. Interrelations among plasma renin activity (PRA), aldosterone and Cortisol levels, blood volume, exchangeable sodium, urinary catecholamines, and blood pressure were studied in 35 normal subjects and 60 age-matched non-azotemic patients with diabetes mellitus (60% with hypertension, 15% with orthostatic hypotension). Basal PRA, plasma aldosterone, cortisol, blood volume, plasma potassium, and urinary electrolytes were comparable in diabetic and normal subjects. Diabetic patients, however, had a 10% increase in body sodium (P < 0.01), and 8% of them showed normal postural PRA responses and subnormal aldosterone responses; 22% had subnormal PRA and normal aldosterone responses, and 17% had subnormal responses of PRA and aldosterone. Non-PRA-related aldosterone responses could not be explained by ACTH or electrolytes. Orthostatic decreases in blood pressure correlated (P < 0.01) with both catecholamine excretion and basal PRA. This suggests that in diabetes mellitus, body sodium is increased. Basal PRA and plasma aldosterone are usually normal, but their postural responses are frequently impaired. Absent aldosterone responses, despite normal PRA responsiveness, may reflect an adrenal abnormality or an ineffective form of renin. Marked postural aldosterone stimulation, unrelated to PRA, ACTH, or electrolytes, points to a potent unknown factor in aldosterone control. Low levels of free peripheral catecholamines and PRA may be complementary factors contributing to postural hypotension.Sodium, rénine, aldostérone, catécholamines et pression artérielle dans le diabèté sucré. Les inter-relations entre l'activité rénine plasmatique (PRA), les concentrations d'aldostérone et de cortisol, le volume sanguin, le sodium échangeable, les catécholamines urinaires et la pression artérielle ont été étudiées chez 35 sujets normaux et 60 malades atteints de diabété, sans insuffisance rénale et dont les âges étaient appariés (60% avaient une hypertension et 15% une hypotension orthostatique). La PRA de base, l'aldostérone et le Cortisol plasmatiques, le volume sanguin, le potassium plasmatique et les électrolytes urinaires étaient comparables chez les diabétiques et les sujets normaux. Les malades diabétiques, cependant, ont une augmentation de 10% de leur sodium corporel (P < 0,01). Huit pour cent d'entre eux ont une réponse posturale de PRA normale et une réponse de l'aldostérone inférieure à la normale, 22% ont une réponse de PRA inférieure à la normale et une reponse de l'aldosterone normale, et 17% ont des réponses de PRA et de l'aldostérone inférieures à la normale. Les réponses de l'aldostérone sans rapport avec PRA ne peuvent pas être expliquées par l'ACTH ou les électrolytes. Les diminutions de la pression artérielle liées à l'orthostatisme sont correlées (P < 0,01) à la fois avec l'excrétion de catécholamines et la PRA de base. Ceci suggére qu'au cours du diabéte le sodium corporel est augmenté. La PRA et l'aldosterone de base sont souvent normales mais leur réponse posturale est souvent modifiée. L'absence de réponse de l'aldosterone malgré une réponse normale de PRA peut traduire une anomalie surrénale ou une forme de rénine inefficace. Une stimulation posturale importante de l'aldostérone non expliquée par la PRA, l'ACTH ou les électrolytes oriente vers un facteur inconnu mais puissant du contrôle de la sécrétion d'aldostérone. Des concentrations basses de catécholamines libres et une PRA basse peuvent être des facteurs complémentaires qui participent à l'hypotension posturale

Bremsstrahlung in intermediate-energy nucleon reactions within an effective one-boson exchange model

Within a covariant effective one-boson exchange model for the $T$ matrix of $NN$ interactions we present detailed calculations of bremsstrahlung cross sections for proton - proton and proton - neutron reactions at beam energies in the 1 GeV region. Besides pure bremsstrahlung processes we consider photons from $\Delta$ decays and contributions from the $\eta \to \gamma \gamma$ process. At beam energies above 700 MeV the $\Delta$ decay channel dominates the spectra at large photon energies, where the interference between non-resonance processes and the $\Delta$ decay channel becomes also important. Low energy photons stem from pure bremsstrahlung processes. The available experimental data at 730 MeV beam energy is well described. We extrapolate the model down to 280 MeV, where more detailed experimental data exist, and find agreement with angular distributions.Comment: 20 pages with 10 figures, to be published in Nucl. Phys.