Development of an injectable grout for concrete repair and strengthening

This paper deals with the coupled effect of temperature and silica fume addition on rheological, mechanical behaviour and porosity of grouts based on CEMI 42.5R, proportioned with a polycarboxylate-based high range water reducer. Preliminary tests were conducted to focus on the grout best able to fill a fibrous network since the goal of this study was to develop an optimized grout able to be injected in a mat of steel fibers for concrete strengthening. The grout composition was developed based on criteria for fresh state and hardened state properties. For a CEMI 42.5R based grout different high range water reducer dosages (0%, 0.2%, 0.4%, 0.5%, 0.7%) and silica fume (SF) dosages (0%, 2%, 4%) were tested (as replacement of cement by mass). Rheological measurements were used to investigate the effect of polycarboxylates (PCEs) and SF dosage on grout properties, particularly its workability loss, as the mix was to be injected in a matrix of steel fibers for concrete jacketing. The workability behaviour was characterized by the rheological parameters yield stress and plastic viscosity (for different grout temperatures and resting times), as well as the procedures of mini slump cone and funnel flow time. Then, further development focused only on the best grout compositions. The cement substitution by 2% of SF exhibited the best overall behaviour and was considered as the most promising compared to the others compositions tested. Concerning the fresh state analysis, a significant workability loss was detected if grout temperature increased above 35 degrees C. Below this temperature the grout presented a self-levelling behaviour and a life time equal to 45 min. In the hardened state, silica fumes increased not only the grout's porosity but also the grout's compressive strength at later ages, since the pozzolanic contribution to the compressive strength does not occur until 28 d and beyond. (C) 2012 Elsevier Ltd. All rights reserved.

Effects of age and gender on peripheral lymphocyte micronucleus

Aging in humans appears to be associated with genetic instability. The cytokinesis-blocked micronucleus assay (CBMN) is a comprehensive method for measuring chromosome breakage, DNA misrepair, chromosome loss, non-disjunction, necrosis, apoptosis and cytostasis. Age and gender are the most important demographic variables affecting the micronucleus (MN) index and studies report frequencies in females being greater than those in males by a factor of 1.2 to 1.6 depending on the age group. It has been shown that a higher MN frequency directly corresponds to a decreased efficiency of DNA repair and increased genome instability.

The influence of genetic polymorphisms in XRCC3 and ADH5 genes on the frequency of genotoxicity biomarkers in workers exposed to formaldehyde

The International Agency for Research on Cancer classified formaldehyde as carcinogenic to humans because there is ���sufficient epidemiological evidence that it causes nasopharyngeal cancer in humans���. Genes involved in DNA repair and maintenance of genome integrity are critically involved in protecting against mutations that lead to cancer and/or inherited genetic disease. Association studies have recently provided evidence for a link between DNA repair polymorphisms and micronucleus (MN) induction. We used the cytokinesis-block micronucleus (CBMN assay) in peripheral lymphocytes and MN test in buccal cells to investigate the effects of XRCC3 Thr241Met, ADH5 Val309Ile, and Asp353Glu polymorphisms on the frequency of genotoxicity biomarkers in individuals occupationally exposed to formaldehyde (n = 54) and unexposed workers (n = 82). XRCC3 participates in DNA double-strand break/recombination repair, while ADH5 is an important component of cellular metabolism for the elimination of formaldehyde. Exposed workers had significantly higher frequencies (P < 0.01) than controls for all genotoxicity biomarkers evaluated in this study. Moreover, there were significant associations between XRCC3 genotypes and nuclear buds, namely XRCC3 Met/Met (OR = 3.975, CI 1.053���14.998, P = 0.042) and XRCC3 Thr/Met (OR = 5.632, CI 1.673���18.961, P = 0.005) in comparison with XRCC3 Thr/Thr. ADH5 polymorphisms did not show significant effects. This study highlights the importance of integrating genotoxicity biomarkers and genetic polymorphisms in human biomonitoring studies.

Experimental study of the mechanical properties and durability of self-compacting mortars with nano materials (SiO2 and TiO2)

Resumo: Cement, as well as the remaining constituents of self-compacting mortars, must be carefully selected, in order to obtain an adequate composition with a granular mix as compact as possible and a good performance in the fresh state (self-compacting effect) and the hardened state (mechanical and durability-related behavior). Therefore in this work the possibility of incorporating nano particles in self-compacting mortars was studied. Nano materials are very reactive due mostly to their high specific surface and show a great potential to improve the properties of these mortars, both in mechanical and durability terms. In this work two nano materials were used, nano silica (nano SiO2) in colloidal state and nano titanium (nano TiO2) in amorphous state, in two types of self-compacting mortars (ratio binder:sand of 1:1 and 1:2). The self-compacting mortar mixes have the same water/cement ratio and 30% of replacement of cement with fly ashes. The influence of nano materials nano-SiO2 and nano-TiO2 on the fresh and hardened state properties of these self-compacting mortars was studied. The results show that the use of nano materials in repair and rehabilitation mortars has significant potential but still needs to be optimized. (C) 2015 Elsevier Ltd. All rights reserved.

Genotoxicity biomarkers in occupational exposure to formaldehyde: the case of histopathology laboratories

Formaldehyde, classified by the IARC as carcinogenic in humans and experimental animals, is a chemical agent that is widely used in histopathology laboratories. The exposure to this substance is epidemiologically linked to cancer and to nuclear changes detected by the cytokinesis-block micronucleus test (CBMN). This method is extensively used in molecular epidemiology, since it provides information on several biomarkers of genotoxicity, such as micronuclei (MN), which are biomarkers of chromosomes breakage or loss, nucleoplasmic bridges (NPB), common biomarkers of chromosome rearrangement, poor repair and/or telomere fusion, and nuclear buds (NBUD), biomarkers of elimination of amplified DNA. The aim of this study is to compare the frequency of genotoxicity biomarkers, provided by the CBMN assay in peripheral lymphocytes and the MN test in buccal cells, between individuals occupationally exposed and non-exposed to formaldehyde and other environmental factors, namely tobacco and alcohol consumption. The sample comprised two groups: 56 individuals occupationally exposed to formaldehyde (cases) and 85 unexposed individuals (controls), from whom both peripheral blood and exfoliated epithelial cells of the oral mucosa were collected in order to measure the genetic endpoints proposed in this study. The mean level of TWA8h was 0.16��0.11ppm (<detection limit until 0.51 ppm) and the mean of ceiling values was 1.14��0.74ppm (0.18���2.93 ppm). All genotoxicity biomarkers showed significant increases in exposed workers in comparison with controls (Mann���Whitney test, p < 0.002) and the analysis of confounding factors showed that there were no differences between genders. As for age, only the mean MN frequency in lymphocytes was found significantly higher in elderly people among the exposed groups (p = 0.006), and there was also evidence of an interaction between age and gender with regards to that biomarker in those exposed. Smoking habits did not influence the frequency of the biomarkers, whereas alcohol consumption only influenced the MN frequency in lymphocytes in controls (p = 0.011), with drinkers showing higher mean values. These results provide evidence of the association between occupational exposure to formaldehyde and the presence of genotoxicity biomarkers.

XRCC3241 Polymorphism influence on genotoxicity biomarkers frequency in workers occupationaly exposed to formaldehyde

Formaldehyde (FA) is ubiquitous in the environment and is a chemical agent that possesses high reactivity. Occupational exposure to FA has been shown to induce nasopharyngeal cancer and has been classified as carcinogenic to humans (group 1) on the basis of sufficient evidence in humans and sufficient evidence in experimental animals. The exposure to this substance is epidemiologically linked to cancer and nuclear changes detected by the cytokinesis-block micronucleus test (CBMN). This method is extensively used in molecular epidemiology, since it determines several biomarkers of genotoxicity, such as micronucleus (biomarkers of chromosomes breakage or loss), nucleoplasmic bridges (biomarker of chromosome rearrangement, poor repair and / or telomeres fusion) and nuclear buds (biomarker of elimination of amplified DNA). The gene X-ray repair cross-complementing group 3 (XRCC3) is involved in homologous recombination repair of cross-links and chromosomal double-strand breaks and at least one polymorphism has been reported in codon 241, a substitution of a methionine for a threonine.

Conserva����o, manuten����o e constru����o de patrim��nio estrat��gico das ��guas de Santar��m

A ��gua �� um bem essencial ao ser humano. Nos dias de hoje �� de extrema import��ncia fazer chegar este bem ��s popula����es, um papel que no nosso pa��s �� desempenhado pelos munic��pios, por empresas municipais e por empresas concessionadas. Este relat��rio, enquadrado no ��mbito do trabalho final de mestrado em Engenharia Civil, especializa����o em Hidr��ulica, no Instituto Superior de Engenharia de Lisboa, cujo t��tulo �� ���Conserva����o, Manuten����o e Constru����o de Patrim��nio Estrat��gico das ��guas de Santar��m���, relata a experi��ncia de est��gio do autor do presente relat��rio na A.S. ��� Empresa das ��guas de Santar��m ��� EM, S.A. O relat��rio aborda as tem��ticas do abastecimento de ��gua, do tratamento de ��guas residuais, da constru����o de sistemas de saneamento e esta����es de tratamento de ��guas residuais, da repara����o de equipamentos da empresa e do consumo de energia dos equipamentos da empresa. S��o descritas as actividades desenvolvidas pelo autor, que incluem o acompanhamento activo em visitas a obras de constru����o e manuten����o de patrim��nio, a monitoriza����o e controlo de perdas de ��gua, bem como a actualiza����o em suporte inform��tico do cadastro dos equipamentos pertencentes �� A.S., com a cria����o de fichas de equipamento individuais e de um suporte inform��tico para registo e consulta comparativa de consumos energ��ticos. Esta experi��ncia de est��gio permitiu ao autor um contacto com a realidade de uma empresa em toda a diversidade das actividades anteriormente nomeadas, que ser�� descrita objectivamente nos cap��tulos do presente documento. O est��gio foi claramente enriquecedor para o autor, fornecendo-lhe forma����o objectiva e a prepara����o necess��ria para a sua integra����o no mercado de trabalho nesta ��rea espec��fica da Engenharia Civil.

Levantamento de anomalias nos sistemas impermeabilizantes de coberturas planas

As coberturas planas s��o um dos principais elementos construtivos de uma edifica����o, necessitando por isso de materiais com qualidade e certificados por organismos competentes, bem como de uma conce����o e execu����o minuciosas. Em Portugal, os estudos sobre as anomalias realmente observadas em coberturas planas s��o ainda bastante reduzidos. Nesse ��mbito, o presente trabalho teve como objetivo, efetuar o levantamento e a an��lise estat��stica das principais anomalias e causas identificadas em coberturas planas de 75 edif��cios, permitindo assim a elabora����o de um estudo que possa contribuir para a preven����o dessas anomalias e que indique tamb��m as medidas necess��rias �� repara����o e os respetivos custos associados. As anomalias foram analisadas atrav��s da observa����o "in situ" das coberturas o que conduziu ao preenchimento de fichas de obra com os dados recolhidos. Da an��lise estat��stica efetuada aos edif��cios, verificou-se que as principais anomalias detetadas est��o relacionadas com perfura����es e fissura����es do sistema impermeabilizante, resultantes da falta de conhecimento dos utilizadores. Foi poss��vel verificar erros de execu����o de remates em pontos singulares da cobertura, por falta de pormenores construtivos desses pontos ou erros de execu����o por parte do aplicador. Em muitos dos casos estudados, n��o foi detetada nenhuma anomalia, porque se considerou razo��vel considerar que o sistema impermeabilizante tenha atingido o fim de vida ��til. O custo m��dio por metro quadrado associado �� reabilita����o de uma cobertura plana �� influenciado principalmente por dois fatores: ��rea e acessibilidade da cobertura. O tipo de anomalia e/ou a sua causa n��o determinaram o custo por metro quadrado da repara����o efetuada, pois esta foi sempre de caracter integral e nunca pontual.

A aprendizagem da leitura e da escrita partindo de texto

Projeto de Interven����o apresentado �� Escola Superior de Educa����o de Lisboa para a obten����o de grau de Mestre em Did��tica da L��ngua Portuguesa no 1�� e 2�� CEB

Cytostatics occupational exposure: genotoxic effects assessment

The use of cytostatics drugs in anticancer therapy is increasing. Health care workers can be occupationally exposed to these drugs classified as carcinogenic, mutagenic or teratogenic. Workers may be exposed to this drug, being in the hospital settings the main focus dwelled upon the pharmacy, and nursing personnel. Although the potential therapeutic benefits of hazardous drugs outweigh the risks of side effects for ill patients, exposed health care workers can have the same side effects with no therapeutic benefit. The exposure to these substances is epidemiologically linked to cancer and nuclear changes detected by the cytokinesis-block micronucleus test (CBMN). This method is extensively used in molecular epidemiology, since it determines several biomarkers of genotoxicity, such as micronuclei (MN), which are biomarkers of chromosomes breakage or loss, nucleoplasmic bridges (NPB), common biomarkers of chromosome rearrangement, poor repair and/or telomeres fusion, and nuclear buds (NBUD), biomarkers of elimination of amplified DNA.

Biomonitorization in hospital settings with cytostatics occupational exposure

Exposure in a hospital setting is normally due to the use of several antineoplastic drugs simultaneously. Nevertheless, the effects of such mixtures at the cell level and on human health in general are unpredictable and unique due to differences in practice of hospital oncology departments, in the number of patients, protection devices available, and the experience and safety procedures of medical staff. Health care workers who prepare or administer hazardous drugs or who work in areas where these drugs are used may be exposed to these agents in the air, on work surfaces, contaminated clothing, medical equipment, patient excreta, and other surfaces. These workers include specially pharmacists, pharmacy technicians, and nursing personnel. Exposures may occur through inhalation resulting from aerosolization of powder or liquid during reconstitution and spillage taking place while preparing or administering to patients, through Cytokinesis-block micronucleus test (CBMN) is extensively used in biomonitoring, since it determines several biomarkers of genotoxicity, such as micronuclei (MN), which are biomarkers of chromosomes breakage or loss, nucleoplasmic bridges (NPB), common biomarkers of chromosome rearrangement, poor repair and/or telomeres fusion, and nuclear buds (NBUD), biomarkers of elimination of amplified DNA.

Corros��o das armaduras do bet��o armado: causas, consequ��ncias, preven����o e projeto de durabilidade

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Civil

Mosteiro de Santa Maria de Alcoba��a: an��lise das interven����es efetuadas nos ��ltimos 50 anos, diagn��stico das anomalias actuais e proposta de interven����o futura

Disserta����o para obten����o do grau de Mestre em Engenharia Civil - ��rea de Especializa����o de Edifica����es

Sistemas e solu����es p��s-tens��o na reabilita����o de obras de arte

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Civil