Glass waste powder addition used as mitigator of concrete alkali-silica reaction

The recycled aggregates from demolition of concrete structures affected by alkali silica reaction as well as the potentially reactive natural aggregates are often a matter of great concern and fear in case of new structures construction. Thus, to encourage the recycling and use of some potential reactive aggregates under scientific basis, this paper presents an experimental study where suspected alkali-silica reactive recycled aggregates was used. The main goal of this study is evaluate the influence of waste glass powder addition as mitigator of the concrete expansive reaction. In a first phase, the level of expansibility of different aggregates was identified using accelerated tests in mortars bars, method ASTM C1260 and an adapted accelerated test on specimens of 40 x 40 x 160 mm. In a second phase, tests were performed on concrete mixtures, according to CMBT method, with 100% recycled reactive coarse aggregates and powder addition, such as the glass powder and metakaolin. The powder additions percentages were incorporated at 20%, 40% and 60% of cement weight. The results of mortars bars test showed opposite results according to the method applied, i.e. , the same aggregates considered as harmless by the adapted method are considered reactive by the ASTM method, if the same expansion limit of 0,10% for 16 days was adopted for both methods. Finally, the concrete results obtained with CMBT method showed that glass powder and metakaolin had a significant mitigation effect in alkali-aggregate reaction development

Capacidade de solubilização de fosfatos e eficiência simbiótica de rizóbios isolados de solos da Amazônia

On soils with low available phosphorus, such as the Amazonian upland, the ability of rhizobium strains to solubilize inorganic phosphates is of extreme importance. The objective of this work was to determine the ability of rhizobium isolates from Amazonian soil to solubilize calcium and aluminum phosphate in laboratory, and their symbiotic efficiency to increase N and P contents in cowpea. The rhizobium isolates were evaluated on specific growth media during a period of 15 days, when solubilizing indexes (S.I.) were obtained. From the 205 isolates, 68 solubilized P-Ca and 47 solubilized P-Al, and 32 solubilized P-Ca as well as P-Al. Among the 14 isolates with highest solubilizing activities, eight isolates (INPA R820, INPA R825, INPA R843, INPA R894, INPA R914, INPA R917, INPA R969 and INPA R982) provided higher shoot P and N contents and dry matter

Caracterização fenotípica de rizóbio nativos isolados de solos da Amazônia e eficiência simbiótica em feijão caupi

Biological nitrogen fixation is of fundamental importance for agricultural sustainability, and the evaluation of the rhizobial diversity contributes to the knowledge of their diversity in collections, as well as for later use in agricultural systems. The objective of this paper was to evaluate phenotype diversity and symbiotic efficiency of rhizobia isolates from Amazonian soils when inoculated on cowpea (Vigna unguiculata L. Walp.). The native isolates presented diversity regarding their morphologic and physiological characteristics. It was verified that the inoculation with isolates of native rhizobia contributed to the increase of the biomass, nodulation on cowpea and symbiotic efficiency

Enzimas hidrolíticas extracelulares de isolados de rizóbia nativos da Amazônia Central, Amazonas, Brasil

Legumes enrich the soil by contributing nitrogen through symbiotic biological nitrogen fixation by rhizobia bacteria. However, very little is known about the extracellular enzymatic profile of these microorganisms. In this context, the production of extracellular hydrolytic enzymes by indigenous strains of rhizobia in Central Amazonia was evaluated. This screening constitutes the first step in selecting indigenous microorganisms that are potentially exploitable as enzyme producers. Indigenous strains of rhizobia were screened for extracellular amylolytic, carboxymethylcellulolytic, lactolytic, lipolytic, pectinolytic and proteolytic activities on modified YMA. Ureolytic activity was detected on a urea-agar slant. Rhizobia strains isolated from cowpea nodules produced more enzymes than those isolated from soybean nodules. Out of all the extracellular hydrolytic enzymes evaluated, only pectinase was not detected in this study. The most frequent rhizobia enzymes were amylase (32.8%), protease (28.4%), urease (20.9%) and carboxymethylcellulase (9.0%). In this study, only amylase and protease enzymes varied significantly among rhizobia strains. INPA strains R-926 and R-915 showed the highest enzymatic levels for amylase (EI = 3.1) and protease (EI = 6.6), respectively. This paper showed some indigenous strains of rhizobia from Central Amazonia as promising sources of industrially relevant enzymes for biotechnological purposes

Produção de amilase por rizóbios, usando farinha de pupunha como substrato

Amylases are among the most important industrial enzymes and are of great significance in present-day biotechnology. Although they can be derived from various sources, enzymes from microbial sources are generally the most required by industry. Species of the genus Bacillus are considered to be the main sources of amylases, although screening for new microbial sources is increasing all over the world. The objective of the present study was to evaluate the production of amylase by indigenous rhizobia, using peach palm flour as substrate. In this study, a completely randomized experimental design was adopted with three replicates. Pearson's correlation coefficients were calculated for medium pH, extracellular protein, cellular biomass, mean colony diameter (MCD), mean halo diameter (MHD), enzymatic index (EI) and amylolytic activity variables from the bacteria selected. Out of the 19 rhizobia strains with amylolytic activity on modified YMA, seven (36.8%) strains showed "EI" ≥ 2,1, and they were considered as good producers of amylase. The "IE" presented by bacteria INPA R-987, R-950 and R-915B were significantly lower (p < 0.01) than those shown by the INPA R-926, R-975 and R-957. The amylolytic activity varied significantly (p < 0.01) among the rhizobia strains. INPA R-975 and R-926 strains presented, respectively, the highest (1.00 U.min-1.mL-1) and the lowest (0.31 U.min-1.mL-1) activity average. In general terms, the extracellular protein was correlated positively with "EI" (r = 0.52*; p < 0.05) and "MHD" (r = 0.55*; p < 0.05). The cellular biomass showed positive correlations with amylolytic activity (r = 0.55*; p < 0.05) and "MHD" (r = 0.54*; p < 0.05), and a negative with final pH medium (r = 0.93**; p < 0.01)

Reinforced and prestressed concrete hollow beams under torsion

Recently a new rational theoretical model for beams under torsion has been proposed. This model, called Softened Membrane Model for Torsion (SMMT), is able to predict well the global behaviour of reinforced and prestressed concrete solid beams under torsion. This paper presents a study in order to check the SMMT for reinforced and prestressed concrete hollow beams under torsion. Theoretical predictions from SMMT are compared to some experimental results of hollow beams available in the literature and also with the predictions of another theoretical model previously proposed from the authors. It is shown that SMMT, with some corrections, is able to predict satisfactorily the overall behaviour of reinforced and prestressed concrete hollow beams under torsion

Prevalence of peripheral arterial occlusive disease in patients referred to a tertiary care hospital in Salvador, Bahia, Brazil, for coronary angiography

The presence of peripheral arterial occlusive disease increases the morbidity and mortality of patients with coronary artery disease. The objective of the present study was to calculate the prevalence of peripheral arterial occlusive disease in patients referred for coronary angiography. This prevalence study was carried out at the Hemodynamics Unit of Hospital Santa Isabel, Salvador, Brazil, from December 2004 to April 2005. After approval by the Ethics Committee of the hospital, 397 patients with angiographic signs of coronary artery disease were enrolled. Diagnosis of peripheral arterial occlusive disease was made using the ankle-brachial blood pressure index (£0.90). Statistical analyses were performed using the z test and a level of significance of a = 5%, 95%CI, the chi-square test and t-test, and multiple logistic regression analysis. The prevalence of peripheral arterial occlusive disease was 34.3% (95%CI: 29.4-38.9). Mean age was 65.7 ± 9.4 years for patients with peripheral arterial occlusive disease, and 60.3 ± 9.8 years for patients without peripheral arterial occlusive disease (P = 0.0000003). The prevalence of peripheral arterial occlusive disease was 1.57 times greater in patients with hypertension (P = 0.007) and 2.91 times greater in patients with coronary stenosis ³50% (P = 0.002). Illiterate patients and those with little education had a 44% higher chance of presenting peripheral arterial occlusive disease probably as a result of public health prevention policies of limited effectiveness. The prevalence of peripheral arterial occlusive disease in patients referred to a tertiary care hospital in Salvador, Bahia, for coronary angiography, was 34.3%.Hospital Agenor Paiva Serviço de Cirurgia VascularUniversidade Federal da Bahia Faculdade de Medicina Departamento de Medicina PreventivaUniversidade Estadual de Ciências da Saúde de Alagoas Departamento de CirurgiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de CirurgiaHospital Ana Nery Serviço de Cirurgia Vascular Departamento de Acessos para HemodiáliseEscola Baiana de Medicina e Saúde PúblicaUNIFESP, EPM, Depto. de CirurgiaSciEL

Rectosigmoidectomy in a patient with a prolapsed sigmoid tumor: case report

Modelo de estudo: Relato de caso. Objetivo do estudo: Relatar o caso de uma paciente com prolapso de tumor colorretal localizado no sigmóide. Metodologia: Relato de caso obtido de prontuário. Resultados: É relatado o caso de uma paciente que aguardava cirurgia para ressecção oncológica de um tumor colorretal, quando foi encaminhada ao serviço de urgências médicas com episódio de prolapso retal contendo massa tumoral pós-evacuação, sem redução espontânea. A paciente foi encaminhada à cirurgia de urgência e submetida a uma abordagem transabdominal, na qual o prolapso foi reduzido, em seguida realizada retossigmoidectomia segundo procedimento de Hartamann com colostomia terminal no cólon descendente. Conclusões: No caso relatado, por tratar-se de um paciente portador de tumor de sigmóide prolapsado, a abordagem de escolha foi a retosigmoidectomia abdominal, seguindo os preceitos oncológicos, com ligadura da artéria mesentérica inferior em sua origem. Importância do problema: O prolapso de tumor de sigmóide, uma situação clínica relativamente incomum na população adulta, e uma complicação mais rara quando se trata dos tumores colorretais, deve ser tratado imediatamente após o diagnóstico para se diminuir o risco de isquemia do segmento prolapsado e sempre que possível oferecer a cirurgia que siga os preceitos oncológicos de tratamento. Comentários: No caso relatado, foi necessário uma abordagem cirúrgica de urgência, sendo a via abdominal escolhida por respeito aos princípios da cirurgia oncológica e ao menor tempo cirúrgicoDesign of the study: Case report. Objectives: To report a case of a patient with colorectal tumor prolapse located in the sigmoid. Methodology: A retrospective case report obtained from medical records. Results: We report a case of a patient awaiting surgery for tumor resection of a colorectal tumor, when she was sent to the service of medical emergencies with an episode of post-evacuation rectal prolapse with a tumor without spontaneous reduction. The patient was referred to emergency surgery and underwent a transabdominal approach, in which the prolapse was reduced then followed by Hartmann's rectosigmodectomy surgical procedure. Conclusions: Sigmoid tumor prolapse require a surgical approach, the approach of choice was abdominal retosigmoidectomy, following the oncological principles, with ligation of the inferior mesenteric artery at its origin. Relevance: Sigmoid tumor prolapse, a relatively unusual clinical situation in adults, and more rare complication when it comes to colorectal tumors, it must be treated immediately after diagnosis to reduce the risk of ischemia prolapsed segment, and whenever possible offer surgery to follow the precepts of cancer treatment. Comments: In the case reported, an emergency surgical approach was necessary, and the abdominal route was chosen following the principles of cancer surgery and shorter surgical tim

Serological survey of bovine viral diarrhea (BVDV-1), brucellosis, and leptospirosis in captive white-lipped peccaries (Tayassu pecari) from the Midwest region in Brazil

The present study was conducted to assess the occurrence of anti-Brucella sp., anti-BVDV-1, and anti-Leptospira spp. antibodies from captive white-lipped peccary (Tayassu pecari). A cross-sectional survey was performed testing 100 serum samples collected in a commercial breeding herd. All samples were submitted to the acidified antigen test (AAT), virus neutralization test (VNT) and microscopic agglutination test (MAT) with live antigens. None of the samples tested agglutinated in the AAT screening test. In the VNT, 28 samples presented a cytotoxic effect and were excluded from the evaluation. For BVDV-1, only one sample (1/72; 1.38%) was positive, with antibody titers of 40. For leptospirosis, 9% (9/100) of the samples reacted to at least one of the 24 serovars tested, with 8% (8/100) positive for serovar Patoc and 1% (1/100) for serovar Grippotyphosa. The maximum titer observed was 100. The identification of antibodies against the serovars Patoc and Grippotyphosa suggests that the sampled individuals have been exposed to the pathogen at some point during their lifetime. Regarding BVDV-1, this may be the first serological survey to describe seropositive samples in tayassuids