13 research outputs found

    Micaceous iron oxide production by application of magnetic separation

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    In this study, different flowsheet options were evaluated to achieve the best upgrading conditions for a micaceous iron oxide ore. The first option included the recovery of micaceous iron oxide particles using a double stage magnetic separation circuit after the grinding and classifying of the ore into coarse (-1000+106 μm) and fine (-106 μm) size fractions. A belt type dry high gradient magnetic separator (BHGMS) was used to beneficiate the coarse fraction. The concentrate of the BHGMS was ground to -106 μm, and combined with the fine fraction produced at screening stage, and subjected to high gradient magnetic separation (HGMS) at 1.2 T. A concentrate grading about 61.33% Fe with 60.3% recovery was obtained applying the separation process incorporating BHGMS and HGMS. A single stage separation circuit considering the use of HGMS after the grinding the ore below 106 μm was employed as the second concentration option. A concentrate having 63.80% Fe with 37.1% weight recovery was obtained in this test. As the highest Fe grade and the lowest S concentration was obtained by application of HGMS after the grinding the ore below 106 μm, and it was decided to conduct a pilot scale study using pulsating HGMS. A concentrate assaying 69.45% Fe with 60.1% weight recovery was produced by operating the pulsating HGMS at 0.6 T. The results showed that it was possible to obtain a micaceous iron oxide concentrate to be used in pigment production using magnetic separation method

    Scimitar syndrome: a European Congenital Heart Surgeons Association (ECHSA) multicentric study

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    BACKGROUND: Scimitar syndrome is a rare congenital heart disease. To evaluate the surgical results, we embarked on the European Congenital Heart Surgeons Association (ECHSA) multicentric study. METHODS AND RESULTS: From January 1997 to December 2007, we collected data on 68 patients who underwent surgery for scimitar syndrome. Primary outcomes included hospital mortality and the efficacy of repair at follow-up. Median age at surgery was 1.4 years (interquartile range, 0.46 to 7.92 years). Forty-four patients (64%) presented with symptoms. Surgical repair included intraatrial baffle in 38 patients (56%; group 1) and reimplantation of the scimitar vein onto the left atrium in 21 patients (31%; group 2). Eight patients underwent right pneumectomy, and 1 had a right lower lobe lobectomy (group 3). Four patients died in hospital (5.9%; 1 patient in group 1, 2.6%; 3 patients in group 3, 33%). Median follow-up time was 4.5 years. There were 2 late deaths (3.1%) resulting from severe pulmonary arterial hypertension. Freedom from scimitar drainage stenosis at 13 years was 83.8% in group 1 and 85.8% in group 2. Four patients in group 1 were reoperated, and 3 patients (2 in group 1 [6%] and 1 in group 2 [4.8%]) required balloon dilation/stenting for scimitar drainage stenosis. CONCLUSIONS: The surgical treatment of this rare syndrome is safe and effective. The majority of patients were asymptomatic at the follow-up control. There were a relatively high incidence of residual scimitar drainage stenosis that is similar between the 2 reported corrective surgical techniques used

    Oral mucosa alterations in a socioeconomically deprived region: prevalence and associated factors

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    This study aimed to evaluate the prevalence and factors associated with oral mucosa alterations in patients from Vale do Jequiti-nhonha, Brazil. The sample consisted of 511 patients of both genders. Questionnaires were used to obtain information about patient gender, age, race, systemic disease state, medication use, cigarette use and alcohol consumption. Physical examinations were then performed to identify lesions of the oral mucosa. Descriptive analyses, Chi-squared tests and logistic regressions were then used to analyze the results (p < 0.05, 95% CI). In this population, 84.9% (434/511) of patients were found to have alterations in their oral mucosa. The most common alterations were melanotic maculae (36.0%), linea alba (33.9%), traumatic ulcers (21.5%), Fordyce's granules (20.4%), coated tongue (12.5%) and fissured tongue (10.0%). Melanotic maculae were more frequently observed in black patients, with an odds ration (OR) of 7.51. Being female was a statistically significant predictive factor for having a visible linea alba (OR: 1.90) and a fissured tongue (OR: 2.11). No statistically significant association was found between the presence of oral lesions and systemic disease, medication use, alcohol use and smoking. The high observed prevalence of melanotic maculae and Fordyce's granules suggests that these alterations could be considered typical characteristics of the population of the Vale do Jequitinhonha. Coated tongue may be related to the socioeconomic deprivation in the region. Furthermore, the high prevalence of traumatic ulcers may be associated with the traumatic agents that caused patients to seek dental care
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