55 research outputs found

    Aplicação de resíduo de vidro no concreto como substituto parcial à areia / Application of glass waste in concrete as a partial substitute for sand

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    A utilização de resíduos como material substituto parcial ou total dos componentes do concreto é uma alternativa às tecnologias tradicionais que visa minimizar a extração desiquilibrada dos recursos naturais. Este trabalho tem como objetivo analisar a influência da substituição de areia por resíduo de vidro no concreto nos teores de 10, 20 e 30%. Para atingir este objetivo, realizou-se a caracterização dos resíduos utilizados, fabricação de corpos de prova de concretos com diferentes teores de substituição parcial de agregado miúdo, determinação da resistência à compressão e absorção de água. A partir da análise comparativa entre resultados os ensaios das amostras com e sem a substituição, verificou-se que o pó de vidro é um resíduo viável como um substituto parcial do agregado miúdo para a fabricação de elementos não estruturais na construção civil que não necessitem de alta resistência à compressão, como os pavers e placas de concreto para o passeio público. Assim, outros estudos são necessários para complementar a compreensão da aplicação do resíduo e suas influências na característica dos concretos

    Development of an integrated environmental monitoring protocol for SARS-CoV-2 contamination. Applications at the IRCSS San Martino Polyclinic Hospital in Genoa, Italy

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    Scientific background: Environmental sampling of SARS-CoV-2 is a fundamental tool for evaluating the effectiveness of non-specific prophylaxis measures in counting their spread. The purpose of our work was to evaluate the effectiveness of the different sampling methods in the hospital setting to assess their correlation with the structural, functional, and operational situation of the monitored departments and to define the dynamics of the spread of the virus in indoor environments. Methods: The monitoring was carried out at the San Martino Polyclinic Hospital (Genoa, Italy) in the period from April 2020 to June 2021. The presence of viral RNA in the collected samples was evaluated by qPCR. The infection capacity of the sample collected was also evaluated by an in vitro challenge test on cells sensitive to SARS-CoV-2 infection. Results: The percentage of positivity with respect to the number of tests performed (sensitivity) were bubbler 50%, wipe test 17%, and challenge test 11%. Only 20% of the samples tested positive in the wipe test and 43% of the samples tested positive in the bubbler sampling were also positive in the challenge test. All the positivity obtained was detected at a distance of less than 2\u202fm and height of less than 1.5 from COVID-19 patient. Conclusions: Environmental contamination from SARS-CoV-2 detected at the San Martino Polyclinic Hospital is found lower than similar assessments performed in other hospitals both in Italy and abroad. Our study predicted that environmental monitoring of SARS-CoV-2 must be carried out in an integrated way by not using a single sampling method, as each individual test has a different biological significance and performance. However, the virus detected by wipe test is not a degraded viral fragment but an intact infecting virion, only in a modest percentage of cases

    Mobile laminar air flow screen for additional operating room ventilation: reduction of intraoperative bacterial contamination during total knee arthroplasty

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    Background Surgical site infections are important complications in orthopedic surgery. A mobile laminar air flow (LAF) screen could represent a useful addition to an operating room (OR) with conventional turbulent air ventilation (12.5 air changes/h), as it could decrease the bacterial count near the operating field. The purpose of this study was to evaluate LAF efficacy at reducing bacterial contamination in the surgical area during 34 total knee arthroplasties (TKAs). Materials and methods The additional unit was used in 17 operations; the LAF was positioned beside the operating table between two of the surgeons, with the air flow directed towards the surgical area (wound). The whole team wore conventional OR clothing and the correct hygiene procedures and rituals were used. Bacterial air contamination (CFU/m3) was evaluated in the wound area in 17 operations with the LAF unit and 17 without the LAF unit. Results The LAF unit reduced the mean bacterial count in the wound area from 23.5 CFU/m3 without the LAF to 3.5 CFU/m3 with the LAF (P<0.0001), which is below the suggested limit for anORwith ultraclean laminar ventilation. There were no significant differences in the mean bacterial count in the instrument table area: 28.6 CFU/m3 were recorded with the LAF (N = 6) unit and 30.8 CFU/m3 (N = 6) without the LAF unit (P = 0.631). During six operations with LAF and six without LAF, particle counts were performed and the number of 0.5 lm particles was analyzed. The particle counts decreased significantly when the LAF unit was used (P = 0.003). Conclusion When a mobile LAF unit was added to the standard OR ventilation, bacterial contamination of the wound area significantly decreased to below the accepted level for an ultraclean OR, preventing SSI infections

    Modeling the brown eye spot sampling in arabica coffee.

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    Coffee production has a great socioeconomic importance for Brazil. It generates direct and indirect jobs, and foreign exchange, with Brazilian Arabica coffee production estimated between 42 - 46 million bags (60 kg) in 2020. It is the main agribusiness activity in the State of Espírito Santo, Brazil with expected production between 13 - 15 million bags, and around 30% of this production is Arabica coffee. Technologies are recommended to coffee growers to increase yield, and production of specialty coffees on sustainable properties. Among the principles of integrated management is the monitoring of pests and diseases to determine the level of pest control. The estimate of the number of leaves to be sampled in the monitoring becomes an important tool to increase the accuracy of the obtained information. This research was carried out aiming to determine the minimum number of leaves necessary to evaluate the infestation of brown eye spot (BES) of coffee in Arabica coffee (Coffea arabica L.) without affecting the accuracy of the collection method. It was observed that the estimate of the minimum number for sampling was 46 leaves for the characteristics of incidence, and severity of BES in Arabica coffee. The modeling applied in this study allows to conclude that it is possible to recommend an optimum number of Arabica coffee leaves for these edaphoclimatic conditions, and variety, and it can serve as a basis for monitoring in an integrated pest and disease management program in Arabica coffee

    Identification and characterization of Rhipicephalus (Boophilus) microplus candidate protective antigens for the control of cattle tick infestations

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    The cattle ticks, Rhipicephalus (Boophilus) spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant Rhipicephalus microplus Bm86 antigen has been shown to protect cattle against tick infestations. However, variable efficacy of Bm86-based vaccines against geographic tick strains has encouraged the research for additional tick-protective antigens. Herein, we describe the analysis of R. microplus glutathione-S transferase, ubiquitin (UBQ), selenoprotein W, elongation factor-1 alpha, and subolesin (SUB) complementary DNAs (cDNAs) by RNA interference (RNAi) in R. microplus and Rhipicephalus annulatus. Candidate protective antigens were selected for vaccination experiments based on the effect of gene knockdown on tick mortality, feeding, and fertility. Two cDNA clones encoding for UBQ and SUB were used for cattle vaccination and infestation with R. microplus and R. annulatus. Control groups were immunized with recombinant Bm86 or adjuvant/saline. The highest vaccine efficacy for the control of tick infestations was obtained for Bm86. Although with low immunogenic response, the results with the SUB vaccine encourage further investigations on the use of recombinant subolesin alone or in combination with other antigens for the control of cattle tick infestations. The UBQ peptide showed low immunogenicity, and the results of the vaccination trial were inconclusive to assess the protective efficacy of this antigen. These experiments showed that RNAi could be used for the selection of candidate tick-protective antigens. However, vaccination trials are necessary to evaluate the effect of recombinant antigens in the control of tick infestations, a process that requires efficient recombinant protein production and formulation systems
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