Leaching of Copper Concentrates with Iodized Salts in a Saline Acid Medium: Part 2-Effect on Chloride Concentration and an Aerated System.

To enhance the leaching of chalcopyrite concentrates, this study evaluated a new process for extracting copper using iodized solutions and sulfuric acid diluted in seawater without pressure or high temperatures. The work involved a leaching test carried out under various conditions by varying the concentrations of chloride ions, H2SO4, and an evenly distributed oxygen supply in an aeration system. It was demonstrated that Cl- ion addition could promote the chalcopyrite-leaching process. The leaching efficiency of copper reached 70% after 96 h. However, a chloride ion dosage excess can have the opposite effect on extraction, reducing copper recovery. XRD and SEM-EDS results showed that cuprous chloride (CuCl) was formed at high dosages (>0.5 M); meanwhile, at a lower dosage, elemental sulfur (S) was formed in the presence of sulfuric acid solution and seawater medium. In contrast, in an aerated system, surface roughness markedly increased due to continuous oxidation on the surface of the ore. This change in morphology and the high value of the redox potential, given by the aerated system and the acidic environment, allowed copper recovery of up to 70% after 96 h. The results showed that an aerated system is the most effective factor in chalcopyrite concentrate leaching.

Structure, biomass, and secondary production of benthic macroinvertebrates in subtropical Andean rivers.

Secondary production is the formation of heterotrophic biomass across time, which integrates several important ecological processes that affect the life of organisms, populations, communities and ecosystems, but its study has poor developed in South America. The objectives of this work were to describe the diversity of benthic macroinvertebrate assemblages in terms of abundance and biomass, and to quantify their secondary production for the first time in Andean rivers. A quantitative sampling scheme was implemented, using a Surber sampler, in three forested streams. Physical-chemical variables, nutrients, organic matter and chlorophyll were measured also. The macroinvertebrates were separated and identified mostly at the species level. Each taxon was assigned to a functional feeding group. Secondary production was estimated for 38 taxa, mostly Diptera, Trichoptera, Coleoptera, and Ephemeroptera. The annual production varied from 3769 to 13916 mg dry mass m-2 y-1. Most abundant taxa were also those with higher production, dominated by Ephemeroptera (Baetidae), Trichoptera (Hydropsychidae) and Diptera (Chironomidae and Simuliidae). Density, biomass, and production of collectors and predators were much higher than the other feeding groups. We expect that our results will be useful to evaluate the effects on stream functioning produced by global warming and other anthropogenic disturbances in our region.

Leaching of Copper Concentrate with Iodized Salts in a Saline Acid Medium: Part 1-Effect of Concentrations.

One of the main problems in processing chalcopyrite ore with hydrometallurgical methods is its refractoriness, which is due to the formation of a layer that inhibits the contact of the ore with the leaching solution, thus reducing the dissolution rate. The main objective of this paper is to evaluate the leaching potential of iodide ions in copper extraction from chalcopyrite concentrate in an acidic seawater medium. Leaching tests were carried out in glass reactors stirred at 45 °C. Parameters such as iodide salt concentration and acidity were evaluated in ranges of 0-5000 ppm and 0-1.0 M, respectively. According to the results obtained, adding iodide ions to a medium acid enhances the leaching kinetics in the chalcopyrite concentrate, observing that it improves copper extraction at low concentrations of 100 ppm KI compared to high concentrations of 5000 ppm KI. As a result, part of the iodide required to oxidize copper tends to sublimate or is associated with other ions producing iodinated compounds such as CuI. Copper extraction reached 45% within the first 96 h, while at 216 h, it reached an extraction of close to 70% copper. The recovery rate improves at potentials between 600 and 650 mV, while at lower potentials, the copper extraction decreases. The mineral surface was analyzed using SEM/EDS and XRD analyses for the identification of precipitates on the surface, finding porous elemental sulfur and precipitated jarosite. An increase in iodide ions improves the leaching kinetics in the chalcopyrite concentrate, observing that it improves copper extraction at low concentrations of 100 ppm KI compared to high concentrations of 5000 ppm KI. As a result, part of the iodide required to oxidize copper tends to sublimate or is associated with other ions producing iodinated compounds such as CuI. Copper extraction reached 45% within the first 96 h, while at 216 h, it reached an extraction of close to 70% copper. The recovery rate improves at potentials between 600 and 650 mV, while at lower potentials, the copper extraction decreases. The mineral surface was analyzed using SEM/EDS and XRD analyses for the identification of precipitates on the surface, finding porous elemental sulfur and precipitated jarosite.

Thermodynamic Model for the Design of a Process of Production of Copper Sulfate Pentahydrate from Copper Ores.

In Chile, one of the ways in which small-scale mining industries sustain themselves is through the sale of copper ores to the state company ENAMI, which monetizes this product depending on the copper's mineral grade. To sell this mineral, small mining companies must transport the product to ENAMI, which means a high monetary cost, added to the fact that there are large amounts of waste minerals that cannot be sold because of their low grade. The present work aims that small miners can process these copper ores in situ to commercialize a more valuable product, such as copper salts. Considering the high solar radiation and the scarce superficial water resources found in the north side of the country, a possible process alternative is the leaching of the ores using acid seawater solutions followed by crystallization by solar evaporation. As a necessary tool for this process design, the present work has developed a model able to predict the copper sulfate pentahydrate crystallization from multicomponent solutions, preventing the co-precipitation of undesired compounds (such as iron salts, sodium chloride, and sodium sulphate among others) that contaminate the final product. The Pitzer thermodynamic model was successfully applied to predict the crystallization process of copper sulfate pentahydrate from synthetic leaching solutions. These results were validated through experimental tests.

Implementation of a Brazilian Cardioprotective Nutritional (BALANCE) Program for improvement on quality of diet and secondary prevention of cardiovascular events: A randomized, multicenter trial

Background Complex percutaneous coronary intervention (PCI) is associated with higher ischemic risk, which can be mitigated by long-term dual antiplatelet therapy (DAPT). However, concomitant high bleeding risk (HBR) may be present, making it unclear whether short- or long-term DAPT should be prioritized. Objectives This study investigated the effects of ischemic (by PCI complexity) and bleeding (by PRECISE-DAPT [PRE dicting bleeding Complications in patients undergoing stent Implantation and Sub sequent Dual Anti Platelet Therapy] score) risks on clinical outcomes and on the impact of DAPT duration after coronary stenting. Methods Complex PCI was defined as ≥3 stents implanted and/or ≥3 lesions treated, bifurcation stenting and/or stent length >60 mm, and/or chronic total occlusion revascularization. Ischemic and bleeding outcomes in high (≥25) or non-high (<25) PRECISE-DAPT strata were evaluated based on randomly allocated duration of DAPT. Results Among 14,963 patients from 8 randomized trials, 3,118 underwent complex PCI and experienced a higher rate of ischemic, but not bleeding, events. Long-term DAPT in non-HBR patients reduced ischemic events in both complex (absolute risk difference: −3.86%; 95% confidence interval: −7.71 to +0.06) and noncomplex PCI strata (absolute risk difference: −1.14%; 95% confidence interval: −2.26 to −0.02), but not among HBR patients, regardless of complex PCI features. The bleeding risk according to the Thrombolysis In Myocardial Infarction scale was increased by long-term DAPT only in HBR patients, regardless of PCI complexity. Conclusions Patients who underwent complex PCI had a higher risk of ischemic events, but benefitted from long-term DAPT only if HBR features were not present. These data suggested that when concordant, bleeding, more than ischemic risk, should inform decision-making on the duration of DAPT. (AU)

Influence of organic matter and CO2 supply on bioremediation of heavy metals by Chlorella vulgaris and Scenedesmus almeriensis in a multimetallic matrix.

This research evaluated the influence of organic matter (OM) and CO2 addition on the bioremediation potential of two microalgae typically used for wastewater treatment: Chlorella vulgaris (CV) and Scenedesmus almeriensis (SA). The heavy metal (HM) removal efficiencies and biosorption capacities of both microalgae were determined in multimetallic solutions (As, B, Cu, Mn, and Zn) mimicking the highest pollutant conditions found in the Loa river (Northern Chile). The presence of OM decreased the total biosorption capacity, specially in As (from 2.2 to 0.0 mg/g for CV and from 2.3 to 1.7 mg/g for SA) and Cu (from 3.2 to 2.3 mg/g for CV and from 2.1 to 1.6 mg/g for SA), but its influence declined over time. CO2 addition decreased the total HM biosorption capacity for both microalgae species and inhibited CV growth. Finally, metal recovery using different eluents (HCl, NaOH, and CaCl2) was evaluated at two different concentrations. HCl 0.1 M provided the highest recovery efficiencies, which supported values over 85% of As, 92% of Cu, and ≈100% of Mn and Zn from SA. The presence of OM during the loaded stage resulted in a complete recovery of As, Cu, Mn, and Zn when using HCl 0.1 M as eluent.

Comparative uptake study of arsenic, boron, copper, manganese and zinc from water by different green microalgae.

This work represents a comparative uptake study of the toxic elements arsenic, boron, copper, manganese and zinc in monometallic and multimetallic solutions by four green microalgae species (Chlamydomonas reinhardtii, Chlorella vulgaris, Scenedesmus almeriensis and an indigenous Chlorophyceae spp.), evaluating the effect of pH and contact time. Maximum removal efficiencies for each toxic element were 99.4% for Mn (C. vulgaris, pH 7.0, 3 h), 91.9% for Zn (Chlorophyceae spp., pH 5.5, 3 h), 88% for Cu (Chlorophyceae spp., pH 7.0, 10 min), 40.7% for As (S. almeriensis, pH 9.5, 3 h) and 38.6% for B (S. almeriensis, pH 5.5, 10 min). B removal efficiencies decreased remarkably in multimetallic solutions (down to 0.2% in C. reinhardtii), except for Chlorophyceae spp., the only species isolated from a polluted environment. FTIR spectra shown the highest interactions for As (1150-1300 cm-1) and Cu (3300, 1741, 1535, 1350-1400 cm-1). Results confirm microalgae biomass as a potential biosorbent for toxic elements.

The Brazilian Cardioprotective Nutritional Program to reduce events and risk factors in secondary prevention for cardiovascular disease: study protocol (The BALANCE Program Trial).

This article reports the rationale for the Brazilian Cardioprotective Nutritional Program (BALANCE Program) Trial. This pragmatic, multicenter, nationwide, randomized, concealed, controlled trial was designed to investigate the effects of the BALANCE Program in reducing cardiovascular events. The BALANCE Program consists of a prescribed diet guided by nutritional content recommendations from Brazilian national guidelines using a unique nutritional education strategy, which includes suggestions of affordable foods. In addition, the Program focuses on intensive follow-up through one-on-one visits, group sessions, and phone calls. In this trial, participants 45 years or older with any evidence of established cardiovascular disease will be randomized to the BALANCE or control groups. Those in the BALANCE group will receive the afore mentioned program interventions, while controls will be given generic advice on how to follow a low-fat, low-energy, low-sodium, and low-cholesterol diet, with a view to achieving Brazilian nutritional guideline recommendations. The primary outcome is a composite of death (any cause), cardiac arrest, acute myocardial infarction, stroke, myocardial revascularization, amputation for peripheral arterial disease, or hospitalization for unstable angina. A total of 2468 patients will be enrolled in 34 sites and followed up for up to 48 months. If the BALANCE Program is found to decrease cardiovascular events and reduce risk factors, this may represent an advance in the care of patients with cardiovascular disease.

Pediculosis de la cabeza en escolares de Ciudad Bolívar, estado Bolívar, Venezuela / Headlice in schoolchildren from Ciudad Bolívar, Bolívar state, Venezuela

Entre abril y julio de 2013 se realizó un estudio de tipo transversal, para determinar la prevalencia de pediculosis de la cabeza en niños de 6-15 años, matriculados en cuatro escuelas de Ciudad Bolívar, estado Bolívar, Venezuela. El diagnóstico parasitológico se realizó por observación directa de huevos, ninfas y/o adultos sobre el cuero cabelludo y/o el pelo. Se llenó una ficha clínico-epidemiológica a cada participante previa firma del consentimiento informado por parte de padres o representantes. Se evaluaron 697 niños (40,3%) de los 1730 escolares matriculados, determinándose una prevalencia de 25,1% (175/697). Las niñas resultaron significativamente más infectadas (42,4%) (OR: 9,35 p<0,05). Todos los grupos de edad fueron afectados (χ² (corrección de Yates)=6,90 g.l.: 4 p>0,05) aunque predominó el grupo de 8-11 años. Los factores asociados a una mayor prevalencia de pediculosis de la cabeza fueron: el género femenino (OR: 9,35 p<0,05), haber padecido anteriormente la enfermedad (OR: 5,76 p<0,05) y tener el pelo largo (OR: 7,12 p<0,05) y sucio (OR: 2,20 p<0,05). En conclusión, aunque la prevalencia de pediculosis de la cabeza fue relativamente baja (25,1%), se verifica que esta parasitosis sigue siendo un problema médico importante en escolares de Ciudad Bolívar.

Between April and July 2013 a cross sectional study was conducted to determine the prevalence of headlice in children aged 6-15 years enrolled in four schools in Ciudad Bolívar, Bolivar State, Venezuela. The parasitological diagnosis was made by direct observation of eggs, nymphs and/ or adults on the scalp and/or hair. After signing the informed consent, we filled a clinical and epidemiologic record to each participant. 697 children (40.3%) of the 1730 school enrollment were evaluated, determining a prevalence of 25.1% (175/697). Girls were significantly more infected (42.4%) (OR: 9.35 p<0.05). All age groups were affected (χ2 (Yates correction) = 6.90 d.f.: 4 p> 0.05), but the group of 8-11 years was predominant (70.3%). Factors associated with a higher prevalence of headlice were female (OR: 9.35 p<0.05), having previously had the disease (OR: 5.76 p<0.05) and have long hair (OR: 7.12 p<0.05) and dirty (OR: 2.20 p<0.05). In conclusion, although the headlice prevalence was relatively low (25.1%), we verified that this parasitoses remains a major medical problem in schoolchildren in Ciudad Bolivar.

Infección congénita por CMV: a propósito de dos casos de gemelas univitelinas / Congenital infections by CMV: at proposite two cases of twins

Se presenta el caso de dos lactantes menores de seis meses de edad (gemelas univitelinas) con diagnóstico de Infección Congénita por Citomegalovirus, propuesto por presentación clínica de microcefalia y trastorno general del desarrollo psicomotor, además de hallazgo de calcificaciones periventriculares bilaterales en la Tomografía Axial Computarizada de cráneo. Diagnóstico corroborado por serología, con títulos elevados de "IgG" para CMV tanto en suero materno, como en suero de ambas pacientes

Asociación de fibrosis quística y reflujo gastroesofágico / Association between cystic fibrosis and gastroesophageal reflux \"

Con la finalidad de estudiar la asociación de fibrosis quística y reflujo gastroesofágico en nuestro medio, se revisaron 65 historias de pacientes con diagnóstico de fibrosis quística, controlados en el Servicio de Gastroenterología del Hospital de Niños J.M. de los Rios, en los cuales se había realizado al menos uno de los siguientes estudios: radiología convencional de esófago-estómago-duodeno, endoscopia digestiva superior, estudio histológico y pHmetría. Las edades oscilaron entre 2 meses y 15 años, predominando el sexo masculino (63 por ciento). En 56 pacientes (86,1 por ciento) se realizó estudio radiológico, evidenciándose en 38 (67,8 por ciento), reflujo gastroesofágico. La endoscopia digestiva superior se llevó a cabo en 45 casos (69,2 por ciento), encontrándose en 44 (97,7 por ciento), algún grado de esofagitis. El estudio histológico realizado en 36 pacientes (55,3 por ciento), reportó variados grado de esofagitis en 35 (97,2 por ciento), resaltando en 2 de ellos (5,7 por ciento) el hallazgo de esófago de Barrett. En 2 pacientes (3 por ciento) se practicó pHmetría, cuyo resultado fue patológico. Se realizaron estudios radiológicos, endoscópicos e histológicos en 27 pacientes (41,5 por ciento), evidenciandose en 21 (77,7 por ciento) reflujo gastroesofágico en la radiología y variados grados de esofagitis en los restantes estudios. Se concluye que el reflujo gastroesofágico es una patología frecuentemente asociada a la fibrosis quística y que el estudio radiológico, endoscópico, histológico así como la pHmetría, son métodos útiles en el diagnóstico del mismo

Esclerosis de várices esofágicas en niños con hipertensión portal / Esophageal sclerotherapy in children with portal hypertension

102 pacientes con diagnóstico de Hipertensión Portal(HTP) fueron evaluados en el hospital desde 1987 hasta 1995. A 57 se les realizó 2 o más sesiones de escleroterapia, 38 (66,6 por ciento) fueron del sexo masculino. La edad promedio al momento del diagnóstico fue 3.96 años (rango 2 meses-15 años). 33/57 (57,9 por ciento presentaban antecedentes neonatales (característico de la vena umbilical 31, sepsis 2). La hemorragia digestiva superior fue la forma de presentación más frecuente 63.2 por ciento seguida por esplenomegalía 35 por ciento y anemia 1.75 por ciento. El número de episodios de sangramientos fue 208, media de 3.6 y rango de 0-22. Se hicieron 279 sesiones de escleroterapia, media de 4.9 y rango de 2-18. Al comparar sangramiento y riesgo sangramiento paciente/mes, en el período post-tratamiento con pre y durante tratamiento se observó una diferencia altamente significativa. Se logró la obliteración de las várices esofágicas en 25 pacientes (44 por ciento) y una disminución significativa del calibre en 24 (42 por ciento) permaneciendo 8 sin variación

Linfangiectasia intenstinal en niño: presentación de tres casos / Primary intestinal lymphangiectasia in children: report of three cases

Se reportan tres casos de Linfangiectasia Intestinal Primaria que reportaron la triada común de diarrea, edema e hipoalbuminemia, en los cuales pudemos observar las variaciones clínicas que puede presentar esta entidad. Se demostró la importancia de la biopsia intestinal para lograr un diagnóstico preciso, así como, lo indisopensable del uso de los triglicéridos de cadena media con la restricción de las grasas comunes, para recuperar a estos pacientes