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Background Acidophilic microorganisms like Leptospirillum sp. CF-1 thrive in environments with extremely low pH and high concentrations of dissolved heavy metals that can induce the generation of reactive oxygen species (ROS). Several hypothetical genes and proteins from Leptospirillum sp. CF-1 are known to be up-regulated under oxidative stress conditions. Results In the present work, the function of hypothetical gene ABH19_09590 from Leptospirillum sp. CF-1 was studied. Heterologous expression of this gene in Escherichia coli led to an increase in the ability to grow under oxidant conditions with 5 mM K2CrO4 or 5 mM H2O2. Similarly, a significant reduction in ROS production in E. coli transformed with a plasmid carrying ABH19_09590 was observed after exposure to these oxidative stress elicitors for 30 min, compared to a strain complemented with the empty vector. A co-transcriptional study using RT-PCR showed that ABH19_09590 is contained in an operon, here named the “och” operon, that also contains ABH19_09585, ABH19_09595 and ABH19_09600 genes. The expression of the och operon was significantly up-regulated in Leptospirillum sp. CF-1 exposed to 5 mM K2CrO4 for 15 and 30 min. Genes of this operon potentially encode a NADH:ubiquinone oxidoreductase, a CXXC motif-containing protein likely involved in thiol/disulfide exchange, a hypothetical protein, and a di-hydroxy-acid dehydratase. A comparative genomic analysis revealed that the och operon is a characteristic genetic determinant of the Leptospirillum genus that is not present in other acidophiles. Conclusions Altogether, these results suggest that the och operon plays a protective role against chromate and hydrogen peroxide and is an important mechanism required to face polyextremophilic conditions in acid environments.

The bur used to construct the bed where a dental implant is installed is extremely important to treatment success. The aim of this investigation was to analyze the relationship between bur diameter and implant diameter in different areas. A descriptive study was designed to analyze 5 commercial brands currently on the market. The manufacturer's instructions were followed to establish the size and type of bur indicated for the study implants, which were regular, with a width between 3.5 mm and 4.0 mm and a length from 12 mm to 13 mm. Drilling from the most apical region, the first measurement of width was established 3 mm cervically, the lower middle measurement 6 mm cervically, the upper middle measurement at 9 mm and the cervical measurement at 12 mm. A scanning electron microscope was used standardized for all measurements; the data were analyzed using the Shapiro-Wilk test and the t-test, having considering a value of p

The bur used to construct the bed where a dental implant is installed is extremely important to treatment success. The aim of this investigation was to analyze the relationship between bur diameter and implant diameter in different areas. A descriptive study was designed to analyze 5 commercial brands currently on the market. The manufacturer's instructions were followed to establish the size and type of bur indicated for the study implants, which were regular, with a width between 3.5 mm and 4.0 mm and a length from 12 mm to 13 mm. Drilling from the most apical region, the first measurement of width was established 3 mm cervically, the lower middle measurement 6 mm cervically, the upper middle measurement at 9 mm and the cervical measurement at 12 mm. A scanning electron microscope was used standardized for all measurements; the data were analyzed using the Shapiro-Wilk test and the t-test, having considering a value of p

La presente investigación ofrece un modelo preliminar para comprender la forma en que directores y profesores conciben el concepto de educación de calidad, el cual fue levantado a partir de las opiniones cualitativas de directores y profesores de 12 establecimientos del país. El modelo propuesto distingue tres niveles de profundidad para organizar los componentes de una educación de calidad. Los dos niveles más profundos incluyen componentes relacionados con el compromiso personal y afectivo con los estudiantes así como la formación valórica y de habilidades para la vida, en tanto que solo el tercero incorpora los resultados de aprendizaje y las variables de gestión escolar. A la luz de este modelo es posible comprender de mejor manera la forma en que los actores educativos se relacionan con las estrategias de evaluación de la calidad (particularmente el Simce), y otras políticas educativas relacionadas. This research offers a preliminary model to represent the way in which schools’ principals and teachers understand the concept of quality education. This model was built on the basis of qualitative opinions of teachers and principals from 12 schools. In order to organize the different components associated with quality education, the proposed model identifes three levels. The two most profound levels include components related to personal and emotional engagement with students, as well as values education and the development of soft skills, or ‘life skills’, while only the third, more superficial level, tackles the academic results and school’s management processes. This model allows to better understand the way in which principals and teachers connect with the strategies for evaluating quality (mainly Simce), as well as other related educational policies.

La evaluación de los Servicios de salud para el mejoramiento de la calidad es una actividad que produce discusiones. El desarrollo de una metodología basada en la percepción de los usuarios sobre los intangibles del servicio es hoy más frecuente, cuidando la inclusión de todos los grupos como son familias con personas con discapacidad. Se estudió la población asignada a un Centro de Salud Familiar (CESFAM) mediante una encuesta validada en la metodología SERVPERF en los hogares a personas mayores de 14 años, con pacientes sin y con discapacidad atendidos bajo la modalidad pública. Se detectaron niveles de valoración con diferencias estadísticamente significativas, siendo más baja para los pacientes discapacitados. El mejoramiento pasa por un enriquecimiento del capital social, especialmente del personal de apoyo al profesional y de un fortalecimiento de elementos secundarios como son folleterías e instructivos. Hay que dar el sentido al servicio público: la satisfacción del usuario The assessment of the health services for improvement of quality is an activity that produces discussions. The development of a new methodology based on the perception of users about intangibles of the service its today more frequent, taking care about the inclusion of all the groups like families with people with handicap members. It was studied the assigned population in a family health center through a survey validated with SERVPERF methodology in persons with more than 14 years old, with patients with disabilities and without them in the public system. It was detected levels of assessment with statistically significantly differences, the lowest rating was for patients with disabilities. The improvement involves enrichment of the social capital, especially of the back up personal to the professional and strengthening of secondary elements like educative printed material. We have to give a sense to the public service: the satisfaction of the users