RESUMO
Jarosite [KFe3(SO4)2(OH)6] minerals are effective scavengers of potentially toxic elements (PTEs) and are abundant, for example, in acid rock/mine drainage scenarios. The retention process is highly relevant for environmental attenuation of heavy metals and metalloids since these are usually highly soluble and thus mobile under acidic conditions. We investigated both macroscopically and at the molecular scale the extent and the effects of concomitant incorporation of As(v) and Pb(ii) into synthetic jarosite at different As/Pb starting molar ratios, using XRD-Rietveld, SEM, ATR-FTIR spectroscopy and wet chemistry. The amount of arsenate substituted in the jarosite structure was larger when Pb(ii) was also incorporated, the former filling up to approximately 33% of the tetrahedral sites normally occupied by SO42-, as compared to 21% when Pb(ii) was absent. Similarly, the amount of Pb(ii) incorporated in the structure was larger when As(v) was also taken up. The jarosite unit cell volume increased as higher amounts of As(v) incorporated into its structure, but simultaneous Pb(ii) incorporation seemed to limit this increase due to its smaller size as compared to K+. The extent to which As and Pb can accommodate in the jarosite structure was found to be limited by concentration maxima under the imposed synthesis conditions. At As/Pb ratios up to 1, Pb-As-jarosites were the only crystalline products. Above this ratio, a mixture of Pb-As-jarosite, anglesite (PbSO4) and poorly-crystalline ferric arsenate (AFA) phases was observed. At the highest As/Pb ratio investigated of 1.80 Pb-As-jarosite was no longer formed. Infrared spectroscopy analysis was applied for the first time here to substituted jarosites with both cations and anions, showing spectral changes in the solids as the As/Pb ratio increased: a characteristic As-O doublet at â¼810 and â¼855 cm-1 was observed upon Pb incorporation, showing an indirect effect of Pb(ii) on the As-O bonds in the jarosite structure. Thus, structural incorporation of Pb plays a pivotal role in the unit cell environment of jarosite to balance the distortion caused by AsO4-for-SO4 substitution. The retention processes found in this work have important environmental implications and impacts: through the synergistic incorporation encountered, remediation enhancement of cationic pollutants such as Pb(ii) is possible in a concomitant fashion with As(v) attenuation in acidic mining and metallurgical environments.
Assuntos
Arsênio/isolamento & purificação , Poluentes Ambientais/isolamento & purificação , Compostos Férricos/química , Chumbo/isolamento & purificação , Minerais/química , Sulfatos/química , Sinergismo Farmacológico , Recuperação e Remediação Ambiental , MineraçãoRESUMO
BACKGROUND: Each year it is estimated in the United States an approximate of 8 million fractures; 5 to 10% develop delayed union or absence of periosteal new bone. There are several factors that can cause delay in fracture healing, among the well known, is the use of prophylactic antithrombotic therapy for deep vein thrombosis (DVT). DVT appears in 40 to 60% of the patients undergoing orthopedic surgery without prophylactic antithrombotic therapy. The goal of this study was to assess whether there is a difference in time of bone healing in lower limb fractures (femur and tibia) comparing rivaroxaban to enoxaparin as the prophylactic antithrombotic management. MATERIAL AND METHODS: We present a retrospective observational and analytic study in a sample of cases. It is a cross-sectional study with patient data from the database of the American British Cowdray (ABC) Medical Center. We included patients with femur and tibia fractures under antithrombotic prophylactic management with rivaroxaban or enoxaparin during the period of January 2011 to December 2012. Our sample included 32 patients separated into two groups. Students t-test was used for comparing parametric variables and the Mann-Whitney U test for nonparametric variables. Linear regression model was preformed considering the variables related to the time it took the fracture to heal. RESULTS: All fractures consolidated in a time of 13 and 14 weeks for rivaroxaban and enoxaparin respectively (p = 0.67). DISCUSSION: We found no difference in bone healing time for lower limb fractures in patients receiving antithrombotic prophylaxis treatment comparing rivaroxaban with enoxaparin.
ANTECEDENTES: En Estados Unidos se presentan aproximadamente ocho millones de fracturas anuales y de ellas entre cinco y 10% desarrollan retraso o ausencia en la consolidación ósea. Existen diferentes factores bien conocidos que promueven este retraso, entre los cuales se encuentra el uso de los antitrombóticos como terapia profiláctica de la trombosis venosa profunda, la cual aparece de 40 a 60% en pacientes que no los utilizan y son sometidos a cirugías ortopédicas. El objetivo de este estudio fue evaluar si existe diferencia en el tiempo de consolidación de las fracturas de los huesos de las extremidades pélvicas (fémur y tibia) en pacientes sometidos a terapia profiláctica antitrombótica comparando rivaroxabán con enoxaparina. MATERIAL Y MÉTODOS: Presentamos un estudio descriptivo y analítico con muestreo a conveniencia de casos retrospectivos. Es un estudio transversal con datos recolectivos. Se revisó la base de datos del Centro Médico ABC y se incluyeron pacientes con diagnóstico de fracturas de fémur y tibia sometidos a manejo profiláctico antitrombótico con rivaroxabán o enoxaparina durante el periodo de Enero 2011 a Diciembre de 2012. La muestra total se constituyó de 32 pacientes divididos en dos grupos. Se utilizó la prueba T de Student para comparar variables paramétricas y la prueba U de Mann-Whitney para las no-paramétricas. Se realizó un modelo de regresión lineal considerando las variables relacionadas con el tiempo de consolidación ósea. RESULTADOS: Todas las fracturas consolidaron, presentando un tiempo de 13 semanas con rivaroxabán y de 14 semanas (p = 0.67) con enoxaparina. DISCUSIÓN: No encontramos diferencia en el tiempo de consolidación de las fracturas de los huesos de las extremidades pélvicas (fémur y tibia) en pacientes que reciben antitrombóticos como profilaxis comparando rivaroxabán con enoxaparina.
Assuntos
Enoxaparina , Fraturas do Fêmur , Rivaroxabana , Fraturas da Tíbia , Trombose Venosa , Anticoagulantes/uso terapêutico , Estudos Transversais , Enoxaparina/uso terapêutico , Fraturas do Fêmur/cirurgia , Humanos , Estudos Retrospectivos , Rivaroxabana/uso terapêutico , Fraturas da Tíbia/cirurgia , Trombose Venosa/prevenção & controleRESUMO
INTRODUCCIÓN: La Revista Ciencia y Trabajo (C&T) es editada por la Fundación Científica y Tecnológica de la Asociación Chilena de Seguridad desde 1999, publica trabajos científicos en temas relaciona dos con la seguridad e higiene industrial, salud ocupacional, calidad de vida laboral y otras disciplinas asociadas al trabajo y medio ambiente. OBJETIVO: Analizar la producción científica de los artículos originales publicados en C&T durante el periodo 1999-2015. MATERIAL Y MÉTODOS: Estudio bibliométrico descriptivo, longitudinal y retrospectivo. Se analizaron las características metodológicas y técnicas específicas en pre vención de riesgos laborales para cada uno de los artículos analizados, asimismo, la visibilidad en SciELO Analytics para los últimos años. RESULTADOS: Se publicaron un total de 430 artículos originales en 52 números con una media de 27 ± 8,8 artículos por año y 8 ± 2,6 artícu los por número. Los años con más artículos fueron 2009, 2010 y 2011. El número de autores por artículo oscila entre 1 a 4 (82%), en su mayo ría de universidades de Latinoamérica, destacando Chile, México y Brasil como los países de mayor contribución. La Psicosociología y Medicina del Trabajo son las temáticas más investigadas respecto a otras técnicas específicas en prevención de riesgos laborales como la Seguridad en el Trabajo y Ergonomía, predominando los estudios trans versales de carácter descriptivo-observacional en el idioma español. CONCLUSIONES: Se evidencia la consolidación de la revista a lo largo del tiempo. Por la antigüedad, publicación regular y demás atributos, la Revista C&T puede plantearse la posibilidad de ser indexada en la base de datos Scopus.
BACKGROUND: The journal Science and Work (C&T) has been pub lished by the Scientific and Technological Foundation of the Chilean Security Association since 1999, it publishes scientific papers on issues related to industrial safety and health, occupational health, quality of work life and other disciplines associated with Work and the environment. Objetive: To analyze the scientific production of the original articles published in C&T during the period 1999-2015. MATERIALS-METHODS: Descriptive, longitudinal and retrospective bibliometric study. We analyzed the specific methodological and technical characteristics in occupational risk prevention for each of the analyzed articles, as well as the visibility in SciELO Analytics for the last years. RESULTS: A total of 430 original articles were published in 52 numbers with an average of 27 ± 8.8 articles per year and 8 ± 2.6 articles per number, the years with the most articles were 2009, 2010 and 2011. The number of authors per article ranges from 1 to 4 (82%), mostly from Latin American universities, Chile, Mexico and Brazil being the countries with the highest contribution. Psychosociology and Occupational Medicine are the most researched topics in relation to other specific techniques in the prevention of occupational hazards such as Occupational Safety and Ergonomics, with cross - sectional descriptive - observational studies predominat ing in the spanish language. CONCLUSIONS: It is evident the consolida tion of the journal over time. Due to seniority, regular publication and other attributes, C&T can consider the possibility of being indexed in the Scopus database.
Assuntos
Publicações Periódicas como Assunto , Bibliometria , Saúde Ocupacional , Chile , Estudos Retrospectivos , Estudos LongitudinaisRESUMO
Abstract: Background: Each year it is estimated in the United States an approximate of 8 million fractures; 5 to 10% develop delayed union or absence of periosteal new bone. There are several factors that can cause delay in fracture healing, among the well known, is the use of prophylactic antithrombotic therapy for deep vein thrombosis (DVT). DVT appears in 40 to 60% of the patients undergoing orthopedic surgery without prophylactic antithrombotic therapy. The goal of this study was to assess whether there is a difference in time of bone healing in lower limb fractures (femur and tibia) comparing rivaroxaban to enoxaparin as the prophylactic antithrombotic management. Material and methods: We present a retrospective observational and analytic study in a sample of cases. It is a cross-sectional study with patient data from the database of the American British Cowdray (ABC) Medical Center. We included patients with femur and tibia fractures under antithrombotic prophylactic management with rivaroxaban or enoxaparin during the period of January 2011 to December 2012. Our sample included 32 patients separated into two groups. Student's t-test was used for comparing parametric variables and the Mann-Whitney U test for nonparametric variables. Linear regression model was preformed considering the variables related to the time it took the fracture to heal. Results: All fractures consolidated in a time of 13 and 14 weeks for rivaroxaban and enoxaparin respectively (p = 0.67). Discussion: We found no difference in bone healing time for lower limb fractures in patients receiving antithrombotic prophylaxis treatment comparing rivaroxaban with enoxaparin.
Resumen: Antecedentes: En Estados Unidos se presentan aproximadamente ocho millones de fracturas anuales y de ellas entre cinco y 10% desarrollan retraso o ausencia en la consolidación ósea. Existen diferentes factores bien conocidos que promueven este retraso, entre los cuales se encuentra el uso de los antitrombóticos como terapia profiláctica de la trombosis venosa profunda, la cual aparece de 40 a 60% en pacientes que no los utilizan y son sometidos a cirugías ortopédicas. El objetivo de este estudio fue evaluar si existe diferencia en el tiempo de consolidación de las fracturas de los huesos de las extremidades pélvicas (fémur y tibia) en pacientes sometidos a terapia profiláctica antitrombótica comparando rivaroxabán con enoxaparina. Material y métodos: Presentamos un estudio descriptivo y analítico con muestreo a conveniencia de casos retrospectivos. Es un estudio transversal con datos recolectivos. Se revisó la base de datos del Centro Médico ABC y se incluyeron pacientes con diagnóstico de fracturas de fémur y tibia sometidos a manejo profiláctico antitrombótico con rivaroxabán o enoxaparina durante el periodo de Enero 2011 a Diciembre de 2012. La muestra total se constituyó de 32 pacientes divididos en dos grupos. Se utilizó la prueba T de Student para comparar variables paramétricas y la prueba U de Mann-Whitney para las no-paramétricas. Se realizó un modelo de regresión lineal considerando las variables relacionadas con el tiempo de consolidación ósea. Resultados: Todas las fracturas consolidaron, presentando un tiempo de 13 semanas con rivaroxabán y de 14 semanas (p = 0.67) con enoxaparina. Discusión: No encontramos diferencia en el tiempo de consolidación de las fracturas de los huesos de las extremidades pélvicas (fémur y tibia) en pacientes que reciben antitrombóticos como profilaxis comparando rivaroxabán con enoxaparina.
Assuntos
Humanos , Fraturas da Tíbia/cirurgia , Enoxaparina/uso terapêutico , Trombose Venosa/prevenção & controle , Fraturas do Fêmur/cirurgia , Rivaroxabana/uso terapêutico , Estudos Transversais , Estudos Retrospectivos , Anticoagulantes/uso terapêuticoRESUMO
This work reports the removal of textile dyes and metallic ions by means of adsorption and coagulation-flocculation using two polyelectrolytes and two macroelectrolytes containing sulfonic acid groups. The adsorption of textile dyes was studied in aqueous solutions containing cationic dyes and in wastewater containing a vat dye. Also, removal of vat and naphthol dyes was studied using the process of coagulation-flocculation. The results show these materials possess elevated adsorption capacity, and they accomplished removal rates above 97% in aqueous solutions. The removal of the vat dye improved the quality of the wastewater notably, and an uncolored effluent was obtained at the end of the treatment. The treatment using adsorption decreased the values for coloration, conductivity, suspended solids, and pH. The removal of vat and naphthol dyes by means of coagulation-flocculation was studied as well, and removal rates of 90% were obtained. The polyelectrolytes and macroelectrolytes also proved effective in the adsorption of metallic ions in wastewater. The treatment using adsorption accomplished high removal rates of metallic ions, and it showed greater selectivity towards Cu(2+), Fe(3+) and Pb(2+). A decrease in the content of solids as well as the values for COD and conductivity was observed in the wastewater as well. The analyses of FT-IR indicated that cationic dyes and metallic ions were chemisorbed by means of ionic exchange.
Assuntos
Corantes/química , Polieletrólitos/química , Ácidos Sulfônicos/química , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/química , Adsorção , Corantes/análise , Floculação , Concentração de Íons de Hidrogênio , Troca Iônica , Espectroscopia de Infravermelho com Transformada de Fourier , Têxteis , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análiseRESUMO
INTRODUCTION: Accumulating evidence amongst dental students indicates an alarming prevalence of stress, which can precipitate the development of burnout--a state of mental or physical exhaustion and disengagement. Understanding individual and educational correlates of burnout is necessary for its prevention. The aims of this study were to determine the prevalence of burnout amongst a large sample of Colombian dental undergraduates and investigate its psychosocial and educational correlates. MATERIALS AND METHODS: Survey data collected from 5647 students participating in the Stress in Colombian Dental Education study were used for this analysis. Burnout was measured using the Maslach Burnout Inventory-Student Survey (MBI-SS). Covariates included participants' socio-demographic characteristics and perceived stress, as well as educational environment factors. Descriptive, bivariate and multivariate methods based on multilevel mixed-effects logistic regression modelling were used for data analysis. RESULTS: Seven per cent of the students surveyed met the criteria for burnout. The prevalence of burnout was higher amongst upper classes, older and married students, those who reported not having passed all required courses and not having dentistry as their first career choice, as well as students in public institutions and those with large class sizes. Moreover, students' perceived stress in the domains of workload and self-efficacy was significantly and positively associated with burnout. CONCLUSIONS: Both personal and educational environment characteristics were found to be associated with burnout. Irrespective of these factors, students' perceived stress with regard to workload and self-efficacy was a strong influence on burnout and its alleviation may be a promising avenue to prevent psychological morbidity.
Assuntos
Esgotamento Profissional/epidemiologia , Esgotamento Profissional/psicologia , Educação em Odontologia , Estudantes de Odontologia/psicologia , Adolescente , Adulto , Colômbia/epidemiologia , Avaliação Educacional , Feminino , Humanos , Masculino , Razão de Chances , Prevalência , Fatores de Risco , Fatores Socioeconômicos , Estresse Psicológico , Inquéritos e Questionários , Carga de Trabalho , Adulto JovemRESUMO
Nearly half of the world's population depends on biomass fuels to meet domestic energy needs, producing high levels of pollutants responsible for substantial morbidity and mortality. We compare carbon monoxide (CO) and particulate matter (PM2.5) exposures and kitchen concentrations in households with study-promoted intervention (OPTIMA-improved stoves and control stoves) in San Marcos Province, Cajamarca Region, Peru. We determined 48-h indoor air concentration levels of CO and PM2.5 in 93 kitchen environments and personal exposure, after OPTIMA-improved stoves had been installed for an average of 7 months. PM2.5 and CO measurements did not differ significantly between OPTIMA-improved stoves and control stoves. Although not statistically significant, a post hoc stratification of OPTIMA-improved stoves by level of performance revealed mean PM2.5 and CO levels of fully functional OPTIMA-improved stoves were 28% lower (n = 20, PM2.5, 136 µg/m(3) 95% CI 54-217) and 45% lower (n = 25, CO, 3.2 ppm, 95% CI 1.5-4.9) in the kitchen environment compared with the control stoves (n = 34, PM2.5, 189 µg/m(3), 95% CI 116-261; n = 44, CO, 5.8 ppm, 95% CI 3.3-8.2). Likewise, although not statistically significant, personal exposures for OPTIMA-improved stoves were 43% and 17% lower for PM2.5 (n = 23) and CO (n = 25), respectively. Stove maintenance and functionality level are factors worthy of consideration for future evaluations of stove interventions.
Assuntos
Poluição do Ar em Ambientes Fechados/prevenção & controle , Culinária/instrumentação , Calefação/instrumentação , Fumaça/análise , Poluição do Ar em Ambientes Fechados/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Exposição Ambiental , Eucalyptus , Feminino , Humanos , Peru , População Rural , MadeiraRESUMO
Background: Radioiodine treatment fails in 17 percent of patients with Basedow Graves disease (BGD). Aim: To assess the frequency and possible associated factors of treatment failure of the first radioiodine dose in patients with BGD. Material and Methods: Review of medical records of patients with BGD treated with radioiodine at a general hospital between 2004 and 2008. Normal thyroid function or hypothyroidism ensuing after treatment were considered as treatment success criteria. Results: According to the databases of the hospital, 298 patients received radioiodine in the study period. Of these, 254 medical records were recovered and 86 were analyzed. Treatment success and failure was recorded in 67 (78 percent) and 19 (22 percent) patients, respectively. The mean dose used was 12 +/- 2 mCi. Clinically determined goiter size and a high free thyroxin level were significantly associated to treatment failure. The area under the receiver operating characteristic curve (ROC) for a thyroid weight over 60 g, estimated clinically was 0.73, rendering a sensitivity and specificity of 63 and 89 percent respectively, for this parameter as predictor or treatment failure. Conclusions: Thyroid gland size may be a predictor of radioiodine treatment failure. However the variability of the clinical estimation of this parameter casts doubts about its usefulness.