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

Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study

: The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity > 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI

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