Advances in composites applied to masonry

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Restoration of heritage masonry buildings

[EN] Restoration of heritage masonry buildings was in the past, until the sixties, a job for a few experts. Damage to historic buildings due to earthquakes and decay due to lack of maintenance and ageing have now implicated a large number of architects and engineers in restoration design; as a consequence there is a great need for guidelines and codes for testing and application of various techniques for preservation as well as for training and teaching. On the following pages, the main recomendations, existing codes∫, development and future necessities are presented.[ES] La restauración de edificios históricos de obra de fábrica, fue, hasta los años setenta, algo reservado para unos pocos expertos. El deterioro de este tipo de construcciones, debido a los últimos sismos, a la carencia de mantenimiento y a su propia antigüedad, ha involucrado en la restauración a un gran número de arquitectos e ingenieros; como consecuencia, se plantea una gran necesidad de guías y códigos para la realización de ensayos, la aplicación de técnicas para la conservación, así como la práctica de la enseñanza. A continuación se presentan las principales recomendaciones, los códigos existentes, el desarrollo y las necesidades de futuro.Binda, L. (1997). La restauración de edificios históricos de obra de fábrica. Loggia, Arquitectura & Restauración. (4):82-91. doi:10.4995/loggia.1997.5381SWORD8291

Diagnosing congenital Cytomegalovirus infection: Don't get rid of dried blood spots

Background: Congenital Cytomegalovirus (cCMV) is a serious global public health issue that can cause irreversible fetal and neonatal congenital defects in symptomatic or asymptomatic newborns at birth. In absence of universal cCMV screening, the retrospective diagnosis of cCMV infection in children is only possible by examining Dried Blood Spot (DBS) samples routinely collected at birth and stored for different time spans depending on the newborn screening regulations in force in different countries. In this article, we summarize the arguments in favor of long-term DBS sample storage for detecting cCMV infection. Main text: CMV infection is the most common cause of congenital infection resulting in severe defects and anomalies that can be apparent at birth or develop in early childhood. Sensorineural hearing loss is the most frequent consequence of cCMV infection and may have a late onset and progress in the first years of life. The virological diagnosis of cCMV is essential for clinical research and public health practices. In fact, in order to assess the natural history of CMV infection and distinguish between congenital or acquired infection, children should be diagnosed early by analyzing biological samples collected in the first weeks of life (3 weeks by using viral culture and 2 weeks by molecular assays), which, unfortunately, are not always available for asymptomatic or mildly symptomatic children. It now seems possible to overcome this problem since the CMV-DNA present in the blood of congenitally infected newborns can be easily retrieved from the DBS samples on the Guthrie cards routinely collected and stored within 3 days from birth in the neonatal screening program for genetic and congenital diseases. Early collection and long-term storage are inexpensive methods for long-term bio-banking and are the key points of DBS testing for the detection of cCMV. Conclusion: DBS sampling is a reliable and inexpensive method for long-term bio-banking, which enables to diagnose known infectious diseases - including cCMV - as well as diseases not jet recognized, therefore their storage sites and long-term storage conditions and durations should be the subject of political decision-making

Novel monomers with N-methyl-D-glucamine segments and their application in structured porous materials for arsenic capture

The N-methyl-D-glucamine moieties exhibit high ability and selectivity toward arsenate ions in water by a complexation mechanism that involves their hydroxyl groups. In this work, the syntheses of two monomers containing N-methyl-D-glucamine, namely 4-vinylbenzyl-N-methyl-D-glucamine (VbNMDG), and N-methyl-D-glucamine methacrylamide (MNMDG) were studied. Different synthetic routes were considered in order to obtain liquid monomers able to polymerize and selectively capture arsenic. Furthermore, the incorporation of protective groups like trimethylsilyl moieties in the molecular structure was assessed to prevent transfer reactions during further polymerization. After polymerization, hydroxyl groups were deprotected using hydrofluoric acid. Following this methodology, structured microporous polymeric films based on colloidal crystal templates were prepared. NMR and FTIR techniques were used to follow the reactions and to determine the chemical structure of the obtained products. The morphology of materials was characterized by SEM. The performances of the developed polymeric films to selectively capture arsenic were determined. Films showed an improved and reproducible sensitivity to arsenic detection exhibiting high values of arsenic capturing capability (around 90%)

Avaliação da Condição Periodontal e da Microbiota Subgengival em Adolescentes Tratados Ortodonticamente Com Aparelho Fixo

Introdução: Aparelhos ortodônticos fixos podem promover o aumento do acúmulo de placa bacteriana, modificando a composição da microbiota subgengival e levar a uma condição de inflamação gengival e, posteriomente, à destruição dos tecidos periodontais de suporte. Objetivo: Avaliar e comparar a condição clínica periodontal e a composição microbiológica da placa subgengival de pacientes adolescentes após o tratamento ortodôntico. Materiais e Métodos: Vinte e três adolescentes com idades entre 10 e 19 anos, em fase de finalização ortodôntica foram selecionados por amostragem não-probabilística por conveniência. Amostras da placa subgengival foram coletadas de seis dentes-índice (16, 11, 26, 36, 31 e 46) para análise microbiológica pela técnica Checkerboard DNA-DNA hybridization e parâmetros clínicos periodontais (Índice de placa visível, Índice de sangramento gengival marginal, Índice de profundidade à sondagem e Sangramento à sondagem) foram avaliados no dia da remoção do aparelho fixo metálico (T1) e seis meses após (T2). Resultados: Houve redução estatisticamente significante dos índices clínicos periodontais seis meses após a remoção do aparelho fixo ortodôntico. Em T2, ocorreu um aumento estatisticamente significante (p<0,05) nas médias de contagem e proporções das bactérias C. showae, F. periodonticum, S. sanguinis, S. gordonii, C. gingivalis, A. odontolyticus I, A. naeslundii I, e redução dos microrganismos F. nucleatum (sp. vincentii), E. saburreum, S. anginosus e P. melaninogenica (p<0,05), com maior frequência de bactérias do complexo laranja (T1: 28,28%; T2: 27,88%). Conclusão: Os aparelhos fixos ortodônticos modificam a saúde clínica periodontal, alterando parâmetros clínicos que tendem a retornar a valores considerados normais após sua remoção, assim como a concentração de bactérias periodontopatogênicas presentes na placa subgengival

Testing and modelling of multiple-leaf masonry walls under shear and compression

Predicting the behaviour of multiple-leaf masonry walls is a challenging issue, given the influence of a wide range of factors as the mechanical properties of the leaves, their dimensions and the way they are connected to each other. In the present paper, experimental results in large specimens are carefully reviewed together with numerical interpretation of the shear and compressive behaviour of multiple-leaf walls. Simplified calculations for practical assessment of existing walls are also addressed.MURST – Cof. 2000, 2002

Heterogeneity of cancer-initiating cells within glioblastoma.

Malignant gliomas, particularly glioblastoma multiforme (GBM), account for the majority of brain tumors. Their incidence is increasing world wide and they are incurable. Although a transient response to therapy is observed, tumor recurrence is inevitable and occurs within tissue that has received cytotoxic therapy. This suggests that a subpopulation of resistant cells is responsible for tumor regrowth. The treatment of GBMs represents a daunting challenge to clinicians due principally to the lack of effective therapeutic options. One explanation for this is the marked cellular and genetic heterogeneity within and across these types of tumors. Unravelling the cellular composition of gliomas and describing cell lineage relationships are essential for therapeutic breakthroughs. The recent proposal that a small percentage of cells with stem cells characteristics are responsible for tumor initiation and growth has sparked an interest in applying approaches used to study somatic stem cells toward an understanding of the cellular elements responsible for cancer progression and recurrence. To outline the relevance of these findings is the purpose of this review

Antibacterial Properties of D-Amino Acid Oxidase: Impact on the Food Industry

Food quality is also related to safety and prevention of spoilage. Biological antimicrobial agents represent suitable alternatives to clinical preservatives in food industry to increase both safety and stability of aliments. Here, we focused on the enzyme D-amino acid oxidase (DAAO) from the yeast Rhodotorula gracilis, a well-studied protein for biotechnological use based on its stability, high activity, and easy recombinant production. DAAO catalyzes the O-2-dependent oxidative deamination of D-enantiomer of amino acids generating alpha -keto acids, ammonia, and hydrogen peroxide. DAAO shows antibacterial activity on both Gram-positive and Gram-negative bacteria in the presence of D-alanine when tested on plates and reduced by half their growth when tested on liquid cultures. Control experiments performed with alternative amino acid-specific flavoenzymes (able or not to generate H2O2 acting on amino acids), a DAAO inactive variant, catalase (H2O2 scavenger), and L-amino acids instead of D-alanine identified H2O2 as the antibacterial agent. DAAO showed a good ability to decrease the bacterial growth on various food stuffs: e.g., 10-fold less colonies were formed on grated cheese incubated for 16 h at 37 degrees C when a tiny amount (0.01 mg corresponding to 1.2 units) of DAAO was added. No exogenous D-amino acids were added since DAAO used the ones naturally occurring or the ones generated during ripening. Notably, simultaneously to H2O2 generation, DAAO also acts as O-2-scavenger thus further hampering food deterioration

Are eco-friendly “green” tires also chemically green? Comparing metals, rubbers and selected organic compounds in green and conventional tires

Tires are a major source of synthetic and natural rubber particles, metals and organic compounds, in which several compounds are linked to negative environmental impact. Recent advances in material technology, coupled with focus on sustainability, have introduced a new range of tires, sold as “green, sustainable, and eco-friendly”. Although these “green” tires may have lower impact on the environment on a global scale, there is no current knowledge about the chemical composition of “green” tires, and whether they are more eco-friendly when considering the release of tire wear particles or tire-associated chemicals. Here we have investigated the chemical composition of nine “green” vehicle tires, one “green” bike tire and seven “conventional” vehicle tires. No significant difference was found between “green” and “conventional” tires tested in this study. For N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), the average concentration in “green” tires were higher (16 ± 7.8 μg/mg) compared to “conventional” tires (8.7 ± 4.5 μg/mg). The relationship between metals, selected organic compounds and rubbers demonstrated large variation across brands, and lower variability between tires grouped according to their seasonal use. This study indicates that more work is needed to understand how the shift towards sustainable tires might change the chemical composition of tires

How to clean and safely remove HF from acid digestion solutions for ultra-trace analysis: a microwave-assisted vessel-inside-vessel protocol

The complete dissolution of silicate-containing materials, often necessary for elemental determination, is generally performed by microwave-assisted digestion involving the forced use of hydrofluoric acid (HF). Although highly efficient in dissolving silicates, this acid exhibits many detrimental effects (e.g., formation of precipitates, corrosiveness to glassware) that make its removal after digestion essential. The displacement of HF is normally achieved by evaporation in open-vessel systems: atmospheric contamination or loss of analytes can occur when fuming-off HF owing to the non-ultraclean conditions necessarily adopted for safety reasons. This aspect strongly hinders determination at the ultra-trace level. To overcome this issue, we propose a clean and safe microwaveassisted procedure to induce the evaporative migration of HF inside a sealed \u201cvessel-inside-vessel\u201d system: up to 99.9% of HF can be removed by performing two additional microwave cycles after sample dissolution. HF migrates from the digestion solution to a scavenger (ultrapure H2O) via a simple physical mechanism, and then, it can be safely dismissed/recycled. The procedure was validated by a soil reference material (NIST 2710), and no external or cross-contamination was observed for the 27 trace elements studied. The results demonstrate the suitability of this protocol for ultra-trace analysis when the utilization of HF is mandatory