Assessment of reagent and regrinding in a flotation circuit

Laboratory flotation tests using a bottom driven cell are reproduced with a high level of confidence. These types of laboratory data are used to investigate the effect of reagent and regrinding of coarse particles in an industrial flotation circuit. The addition of collector (BX) has a significant effect on the flotation response of chalcopyrite in the scavenger bank. The reconstructed recovery-time curve (combine products) is greater than that of the rougher tailings (scavenger feed) prior to reagent addition. By adding collector (BX) in the scavenger feed, the ultimate recovery of chalcopyrite increases 20% which means an increase of 1.7% of chalcopyrite recovery in the scavenger feed. Meanwhile, the reagrinding of coarse particles shows a detrimental effect on the collectorless flotation of an initially hydrophobic chalcopyrite sample. Cyclone underflow, 80% recovery at pH 7.7, was decreased to 40% after regrinding at the same range of pH. The chalcopyrite flotation response immediately after regrinding is severely retarded. It is assumed that the centrifugal action of the cyclone is another important factor restoring the chalcopyrite hydrophobic flotation due to the oxygenation of the slurry. Therefore, additional preconditioning time after a regrinding stage should have a positive change in the recovery of chalcopyrite. The overall flotation response before and after the regrinding stage showed that the cyclone underflow response is slightly slower compared with the combine feed in the first four minutes of flotation. This behavior is related to changes on surface chemistry because of the regrinding of coarse particles

ELECTROKINETIC STUDIES OF MINERALS IN AQUEOUS SOLUTIONS THROUGH ELECTROACOUSTIC MEASUREMENT

Electrokinetic property of various minerals in aqueous solutions has been studied through electroacoustic measurement in the present work. This study was carried out on the particles of calcite (CaCO3), magnetite (Fe3O4), quartz (SiO2), and galena (PbS) in an aqueous NaCl solution. Electrophoretic measurement was also applied to magnetite and quartz particles for the comparison of the two methods. The experimental results have shown that the point of zero charges (PZCs) of calcite, magnetite, and galena were at pH 12.5, 3.8 and 2.8, respectively, while no PZC for quartz appeared in the pH range of 1.5–11. The electroacoustic and electrophoretic measurements have obtained the same PZC and similar curves of zeta potential vs pH for magnetite and quartz particles in aqueous solutions. In addition, it has been found that a specific adsorption of Na+ cation was applied to magnetite surfaces in aqueous solutions if the electrolyte (NaCl) concentration in the solution is high enough, leading the isoelectric point to shift rightward. This observation might be more remarkable in electroacoustic measurement than electrophoretic measurement.Electroacoustic, minerals, electrokinetic property, specific adsorption

Clínica Integrada - ME210 - 202100

1 Curso de especialidad, de la carrera de medicina, de carácter teórico- práctico del ciclo 7, en el que los estudiantes al establecer una buena relación con el paciente y/o familiar realizan la anamnesis, que es una entrevista dirigida al problema de salud que presenta el paciente, realizan el examen físico e integran conocimientos que servirán para establecer el diagnostico por síndromes o problemas y el plan de trabajo. El curso de Clínica integrada busca desarrollar las competencias generales de comunicación escrita y comunicación oral(nivel 2) y las competencias específicas de práctica clínica-diagnóstico (nivel 2) y profesionalismo-sentido ético y legal y responsabilidad profesional(nivel 2). La elaboración de una historia clínica orientada por problemas permitirá al estudiante, plantear un adecuado plan de trabajo y terapéutico para su paciente

Externado de Medicina Interna - ME212 - 202101

Curso de la carrera de medicina, de carácter teórico-práctico del ciclo 9, en el que los estudiantes presentan una historia clínica con su respectivo plan diagnóstico, terapéutico y de procedimientos en un paciente con una condición médica, a través de la realización de actividades de simulación y metodología activa. El curso del externado de medicina interna busca desarrollar la competencia general de comunicación escrita (nivel 3) y las competencias específicas de práctica clínica-diagnóstico(nivel 3) y profesionalismo-sentido ético y legal y responsabilidad profesional(nivel 3). El externado de medicina al estudiante le permitirá plantear un adecuado tratamiento y plan de trabajo según el diagnóstico de los principales problemas médicos que le servirá en su futura vida profesional

Clínica Integrada - ME210 - 202101

Curso de especialidad, de la carrera de medicina, de carácter teórico- práctico del ciclo 7, en el que los estudiantes integran conocimientos previos con la anamnesis, el examen físico y establecen el diagnostico por síndromes o problemas y el plan de trabajo. El curso de Clínica integrada busca desarrollar las competencias generales de comunicación escrita y comunicación oral(nivel 2) y las competencias específicas de práctica clínica-diagnóstico (nivel 2) y profesionalismo-sentido ético y legal y responsabilidad profesional(nivel 2). La integración de conocimientos en la historia clínica, permitirá al estudiante, plantear un adecuado diagnóstico, plan de trabajo para la atención de su futuro paciente

Reproducibility of fluorescent expression from engineered biological constructs in E. coli

We present results of the first large-scale interlaboratory study carried out in synthetic biology, as part of the 2014 and 2015 International Genetically Engineered Machine (iGEM) competitions. Participants at 88 institutions around the world measured fluorescence from three engineered constitutive constructs in E. coli. Few participants were able to measure absolute fluorescence, so data was analyzed in terms of ratios. Precision was strongly related to fluorescent strength, ranging from 1.54-fold standard deviation for the ratio between strong promoters to 5.75-fold for the ratio between the strongest and weakest promoter, and while host strain did not affect expression ratios, choice of instrument did. This result shows that high quantitative precision and reproducibility of results is possible, while at the same time indicating areas needing improved laboratory practices.Peer reviewe

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)