Modelo matemático para la recuperación de oro y zinc mediante el proceso de flotación a partir de minerales sulfurados de zinc marmatitico en la provincia de Casma – Ancash

The present research study demonstrates that the recovery of gold and zinc in gold-containing marmatitic zinc ores is feasible. The recovery of these metals was analyzed by factorial experimental designs, using the reagents: CuSO4, AR-3418 and AR-1242 as independent variables, while all other variables remained constant. As a result of the research, a mathematical model was obtained for the recovery of gold and zinc, performing the adjusted factorial design analysis, as indicated: Recovery of gold (Au) = 83.40+ 0.00600 CuSO4 + 0.110 AR-3418 + 0.035 AR-1242 + 0.000313 CuSO4 * AR 3418+ 0.000275 CuSO4 * AR-1242- 0.00800 AR-3418 * AR-1242 - 0.000011 CuSO4 * AR-3418 * AR-1242. Likewise, the recovery of zinc (Zn) = 73.14 + 0.0100 CuSO4 + 0.132 AR-3418 + 0.051 AR-1242 + 0.000164 CuSO4 * AR-3418 + 0.000131 CuSO4 * AR-1242 - 0.00811 AR-3418 * AR-1242 - 0.000004 CuSO4 * AR-3418 * AR-1242.El presente estudio de investigación demuestra que es viable la recuperación de oro y zinc en minerales de zinc marmatitico con contenido de oro. Se analizó la recuperación de oro y zinc mediante diseños experimentales factoriales, utilizando los reactivos: CuSO4, AR-3418 y AR-1242 como variables independientes; el resto de las variables se mantuvieron constantes. Como resultado de la investigación se obtuvo un modelo para la recuperación de oro y zinc, realizando el análisis del diseño factorial ajustado como se indica: Recuperación de Au = 83.40+ 0.00600 CuSO4+ 0.110 AR-3418+ 0.035 AR-1242+ 0.000313 CuSO4*AR 3418+ 0.000275 CuSO4*AR-1242- 0.00800 AR-3418*AR-1242 - 0.000011 CuSO4*AR-3418*AR-1242. Asimismo, la recuperación de Zn = 73.14 + 0.0100 CuSO4+ 0.132 AR-3418+ 0.051 AR-1242 + 0.000164 CuSO4*AR-3418 + 0.000131 CuSO4*AR-1242 - 0.00811 AR-3418*AR-1242 - 0.000004 CuSO4*AR-3418*AR-1242

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society