Feasibility of re-processing mine tailings to obtain critical raw materials using real options analysis.

The re-processing of mine tailings to obtain critical raw materials (CRMs) could reduce the mining of new deposits as well as ensure the profitable use of the waste materials. Though, it requires large scale industrial installations and the development of specialized technologies to obtain CRMs. New investment in mining activities is an operation, engaging for considerable financial resources involved. The scale of such an endeavor makes a new mining activity a high-risk operation due to several uncertainties present. Therefore, there is an acute need to use new tools to assess the risk associated with the planning and development of new mining activities. This study introduces a framework to evaluate the economic risk related to the re-processing of mine tailings to obtain CRMs. The framework, based on real options analysis (ROA), and sensitivity and uncertainty analysis, was applied to analyze the profitability of using mine tailings as a source of CRMs in the Chilean mining industry. The novelty of this approach consists in enabling the investment decision making including the uncertainties related to a novel investment mining project. RESULTS: show that tailing storage facilities in Chile have some stocks of CRMs, like scandium, whose extraction could be profitable. For the data used, the results of uncertainty and sensitivity analyses show that capital expenditure has a more significant influence than the other variables. Therefore, for the case of mine tailings re-processing, it is essential to develop processes and technologies that enable lower capital expenses.

Recomendaciones médicas para uveítis no infecciosas en adultos

Justificación: Las uveítis no infecciosas constituyen una importante causa de pérdida visual a nivel mundial; por su complejidad y gravedad de complicaciones requieren un abordaje temprano y multidisciplinario. En Costa Rica se desconoce hasta el momento la incidencia global de estas entidades y todavía no existe ningún consenso en cuanto a su manejo. Objetivos: Resumir las recomendaciones terapéuticas vigentes para uveítis no infecciosas en adultos y ofrecer una guía adaptada a la realidad costarricense. Métodos: Se efectuó una revisión no sistemática de bibliografía médica indexada en las plataformas PubMed y Scielo, sobre el manejo médico de las uveítis no infecciosas. De igual manera, se compararon los esquemas terapéuticos recomendados actualmente en América y Europa con el abordaje realizado en los centros hospitalarios costarricenses, para crear una guía adaptada a la realidad nacional. En la elaboración de estas recomendaciones participaron médicos especialistas de todas las clínicas multidisciplinarias especializadas en uveítis del país. Conclusiones: En Costa Rica se cuenta con la mayoría de las opciones disponibles para el tratamiento de uveítis idiopáticas en el sistema público de salud. Se logró la creación de algoritmos de tratamiento para las diferentes patologías.

Summary Background: Noninfectious uveitis represents an important cause of visual loss worldwide, which in view of the severity and complexity of complications demands an early and multidisciplinary approach to therapy. In Costa Rica there is no statistical records of incidence nor consensus of management of these entities to this date. Objectives: To summarize the therapeutic recommendations for non-infectious uveítis according to the scientific evidence and adapt them to the Costa Rican conditions. Methods: A non-systematic review of medical literature indexed on PubMed and Scielo, concerning medical and surgical management of non-infectious uveitis was carried out. Likewise, the recommended therapeutic schemes in America and Europe were compared to the approach used in the Costa Rican hospital centers. In the elaboration of these recommendations participated physicians, specialists of all multidisciplinary clinics for uveitis of the country. Conclusions: In Costa Rica, the majority of alternatives available for the treatment of idiopathic uveitis in the public health system are available. It was possible to create therapeutic algorithms for the different diseases.

Occurrence of porphyromonas gingivalis and its antibacterial susceptibility to metronidazole and tetracycline in patients with chronic periodontitis.

Chronic periodontitis is a multifactorial infectious disease associated with Gram-negative strict anaerobes which are immersed in the subgingival biofilm. Porphyromonas gingivalis, an important periodontal pathogen, is frequently detected in patients with chronic periodontitis. Although isolates of P. gingivalis tend to be susceptible to most antimicrobial agents, relatively little information is available on its in vitro antimicrobial susceptibility. The aim of this study was to determine the frequency of P. gingivalis in patients with chronic periodontitis and to assess antimicrobial susceptibility in terms of minimum inhibitory concentration (MIC) of clinical isolates to metronidazole and tetracycline. A descriptive, observational study was performed including 87 patients with chronic periodontitis. Samples were taken from the periodontal pocket using paper points, which were placed in thioglycollate broth. Samples were incubated for 4 hours at 37°C in anaerobic conditions and finally replated on Wilkins-Chalgren anaerobic agar (Oxoid). Bacteria were identified using the RapIDTMANAII system (Remel) and antimicrobial susceptibility was determined with the M.I.C. Evaluator test (MICE, Oxoid). P. gingivalis was identified in 30 of the 87 patients with chronic periodontitis, which represents a frequency of 34.5%. All 30 isolates (100%) were sensitive to metronidazole, with MIC values ranging from 0015-4ug/ml. Regarding tetracycline, 27 isolates (90%) were sensitive, with MIC values ranging from <0.015 to 4 ug /ml, the remaining three isolates (10%) were resistant to tetracycline with MIC values of 8ug/ ml. There was no statistically significant difference in age, gender, pocket depth, clinical attachment level and severity of periodontitis between the group of patients with chronic periodontitis and P. gingivalis and the group of patients with chronic periodontitis without P. gingivalis. In conclusion, P. gingivalis was found at a frequency of 34.5% in patients with chronic periodontitis and clinical isolates were highly sensitive to metronidazole and tetracycline.

Occurrence of porphyromonas gingivalis and its antibacterial susceptibility to metronidazole and tetracycline in patients with chronic periodontitis. / Occurrence of porphyromonas gingivalis and its antibacterial susceptibility to metronidazole and tetracycline in patients with chronic periodontitis.

Chronic periodontitis is a multifactorial infectious disease associated with Gram-negative strict anaerobes which are immersed in the subgingival biofilm. Porphyromonas gingivalis, an important periodontal pathogen, is frequently detected in patients with chronic periodontitis. Although isolates of P. gingivalis tend to be susceptible to most antimicrobial agents, relatively little information is available on its in vitro antimicrobial susceptibility. The aim of this study was to determine the frequency of P. gingivalis in patients with chronic periodontitis and to assess antimicrobial susceptibility in terms of minimum inhibitory concentration (MIC) of clinical isolates to metronidazole and tetracycline. A descriptive, observational study was performed including 87 patients with chronic periodontitis. Samples were taken from the periodontal pocket using paper points, which were placed in thioglycollate broth. Samples were incubated for 4 hours at 37°C in anaerobic conditions and finally replated on Wilkins-Chalgren anaerobic agar (Oxoid). Bacteria were identified using the RapIDTMANAII system (Remel) and antimicrobial susceptibility was determined with the M.I.C. Evaluator test (MICE, Oxoid). P. gingivalis was identified in 30 of the 87 patients with chronic periodontitis, which represents a frequency of 34.5

. All 30 isolates (100

) were sensitive to metronidazole, with MIC values ranging from 0015-4ug/ml. Regarding tetracycline, 27 isolates (90

) were sensitive, with MIC values ranging from <0.015 to 4 ug /ml, the remaining three isolates (10

) were resistant to tetracycline with MIC values of 8ug/ ml. There was no statistically significant difference in age, gender, pocket depth, clinical attachment level and severity of periodontitis between the group of patients with chronic periodontitis and P. gingivalis and the group of patients with chronic periodontitis without P. gingivalis. In conclusion, P. gingivalis was found at a frequency of 34.5

in patients with chronic periodontitis and clinical isolates were highly sensitive to metronidazole and tetracycline.

Occurrence of Porphyromonas gingivalis and its antibacterial susceptibility to metronidazole and tetracycline in patients with chronic periodontitis

La periodontitis crónica es una enfermedad infecciosa multifactorialasociada a bacilos Gram-negativos anaeróbicos estrictos que se encuentran inmersos en la biopelícula subgingival. Porphyromonas gingivalis, importante patógeno periodontal, es frecuentemente detectado en pacientes con periodontitis crónica. Los aislamientos clínicos de P. gingivalis tienden a ser susceptibles a la mayoría de agentes antimicrobianos; sin embargo, se tiene poca información sobre la susceptibilidad antimicrobiana invitro. El objetivo de este estudio fue determinar la frecuencia de P. gingivalis en pacientes con periodontitis crónica y determinar la susceptibilidad antimicrobiana en términos de concentración inhibitoria mínima (CIM) de los aislamientos clínicos a metronidazol y tetraciclina. Se realizó un estudio observacional descriptivo enel que se incluyeron 87 pacientes con periodontitis crónica. Las muestras tomadas con conos de papel de la bolsa periodontal se depositaron en caldo tioglicolato, se incubaron durante 4 horas a 37 oC en anaerobiosis y se resembraron en agar anaeróbico Wilkins-Chalgren (Oxoid). La identitficación de los aislamientos serealizó con el sistema RapIDTM ANA II (Remel) y la susceptibilidadantibiótica para metronidazol y tetraciclina se evaluó mediante la técnica M.I.C.Evaluator (M.I.C.E., Oxoid). En 30 de los 87 pacientes con periodontitis crónica se identificó P. gingivalis, lo que representa una frecuencia de 34.5 por ciento. Todos los 30 aislamientos (100 por ciento) fueron sensibles al metronidazol con valores de CIM desde 0.015 hasta 4 ug/ml. En cuanto a tetraciclina, 27 aislamientos(90 por ciento) fueron sensibles con valores de CIM desde <0.015 hasta4 ug/ml; los restantes 3 aislamientos (10%) fueron resistentes a tetraciclina con valores de CIM de 8 ug/ml. En cuanto a edad, género, profundidad de bolsa, nivel de inserción clínico y severidad de la periodontitis no se presentaron diferencias estadísticamentesignificativas