Pyridoxine analysis by high performance liquid chromatography and validation in fortified milk powder

Vitamin B6 analysis by reverse-phase high performance liquid chromatography and its validation in milk powder prompted this study. The calibration curves for pyridoxal, pyridoxamine and pyridoxine were evaluated and method precision and accuracy assessed. It was found that the working range was adequate for all the analytes. The analytical procedure was verified by testing the enzymatic efficiency, precision and accuracy. In milk powder samples pyridoxine was the only vitamer found in quantities above the considered limit of quantification and the accuracy showed Z-scores lower than 2. Uncertainty estimation based on method validation results was 0.066 mg/100g, for a vitamin B6 content of 0.61 mg/100 g. It was concluded that the method is adequate for vitamin B6 quantification in powder milk

Tratamiento de regeneración endodóntica en pulpa vital y necrótica, utilizando fibrina rica en plaquetas y Biodentine: reporte de caso

Endodontic regeneration is an inductive and reparative biological treatment indicated to replace cell damage at the level of the dentinopulp complex. The objective of this study is to report a case of Endodontic Regenerative Therapy, in young permanent first molars, in a 10-year-old patient, using platelet-rich fibrin and Biodentine, applying two different protocols for combined diagnoses of irreversible pulpitis and pulp necrosis. The patient attended consultation due to extensive carious lesions. Clinical and imaging evaluations (X-rays and Cone Beam) were performed. The protocol in the necrotic canal consisted of disinfection with a bi-antibiotic paste and placement of a second-generation autologous scaffold matrix, made of biodegradable platelet-rich fibrin which is also , biocompatible and therefore without risk of immune rejection. The protocol in the canals with irreversible pulpitis consisted in a complete pulpotomy and placement of Biodentine calcium silicate cement, a material considered as first choice for pulp-conserving treatments, with properties similar to dentin. Eight weeks after the end of the treatment, a clinical control was conducted revealing an asymptomatic chart and negative palpation without the presence of fistula or abscess. This result indicated regeneration of the pulp tissues and success of the applied protocols. Controls will be carried out at 6, 12 and 18 months. Conclusion: The application of endodontic regenerative treatments, as performed in this reported case, is a favorable and innovative option to preserve, restore or replace the dental pulp. In comparison with conventional treatments, this procedure allows to return pulp functionality, complete development of the root, thickening of the dentinal walls and closure of the apical foramen of young permanent teeth affected by pulp pathologies. It is important that regenerative therapies are publicized and applied by dental professionalsLa regeneración endodóntica es un tratamiento inductivo y reparativo con bases biológicas, indicado para reemplazar los daños celulares a nivel del complejo dentinopulpar. El objetivo de este estudio es reportar un caso de Terapia Regenerativa Endodóntica, en primeros molares permanentes jóvenes, en un paciente de 10 años, a través del uso de fibrina rica en plaquetas y Biodentine, se aplicaron dos protocolos diferentes por diagnósticos combinados de pulpitis irreversible y necrosis pulpar. El paciente acude a consulta por presentar lesiones cariosas extensas; se realizaron evaluaciones clínicas e imagenológicas (radiografías y Cone Beam), el protocolo en el conducto necrótico consistió en la desinfección con pasta biantibiótica y la colocación de una matriz de andamiaje autóloga de segunda generación, elaborada de fibrina rica en plaquetas que es biodegradable, biocompatible y no existe riesgo de rechazo inmunológico. El protocolo en los conductos con pulpitis irreversibles consistió en pulpotomía total y colocación de cemento de silicato de calcio Biodentine, el cual se considera el material de primera elección para los tratamientos conservadores de la pulpa, con propiedades similares a la dentina. A 8 semanas de finalizado el tratamiento se realizó control clínico y el paciente mostró un cuadro asintomático, palpación negativa sin presencia de fístula o absceso lo que podría indicar regeneración de los tejidos pulpares y éxito de los protocolos aplicados. Los siguientes controles se realizán a los 6, 12 y 18 meses. Conclusión: la aplicación de los tratamientos regenerativos endodónticos como se realizó en el caso reportado, es una opción favorable e innovadora para preservar, restaurar o sustituir la pulpa dental, que en comparación con los tratamientos convencionales nos permiten devolver la funcionalidad pulpar, finalizar el desarrollo radicular, engrosamiento de las paredes dentinales y cierre del foramen apical de dientes permanentes jóvenes que han sido afectados por patologías pulpares. Es importante que las terapias regenerativas sean divulgadas y aplicadas por los profesionale

The Intriguing Distribution of Dark Matter in Galaxies

We review the most recent evidence for the amazing properties of the density distribution of dark matter around spiral galaxies. Their rotation curves, coadded according to the galaxy luminosity, conform to an universal profile which can be represented as the sum of an exponential thin disk plus a spherical halo with a flat density core. From dwarfs to giants, these halos feature an inner constant density region. The fine structure of dark matter halos is obtained from the kinematics of a number of suitable low-luminosity disk galaxies. The halo circular velocity increases linearly with radius out to the edge of the stellar disk, implying a constant dark halo density over the entire disk region. The properties of halos around normal spirals provide substantial evidence of a discrepancy between the mass distributions predicted in the Cold Dark Matter scenario and those actually detected around galaxies.Comment: 12 pages, 7 figures. Invited lecture to the 8th Adriatic Meeting: Particle Physics in the New Millennium, Dubrovnik 4-14 Sep. 2001. To be published in the series Lecture Notes in Physics, by Springer Verla

Inflation, cold dark matter, and the central density problem

A problem with high central densities in dark halos has arisen in the context of LCDM cosmologies with scale-invariant initial power spectra. Although n=1 is often justified by appealing to the inflation scenario, inflationary models with mild deviations from scale-invariance are not uncommon and models with significant running of the spectral index are plausible. Even mild deviations from scale-invariance can be important because halo collapse times and densities depend on the relative amount of small-scale power. We choose several popular models of inflation and work out the ramifications for galaxy central densities. For each model, we calculate its COBE-normalized power spectrum and deduce the implied halo densities using a semi-analytic method calibrated against N-body simulations. We compare our predictions to a sample of dark matter-dominated galaxies using a non-parametric measure of the density. While standard n=1, LCDM halos are overdense by a factor of 6, several of our example inflation+CDM models predict halo densities well within the range preferred by observations. We also show how the presence of massive (0.5 eV) neutrinos may help to alleviate the central density problem even with n=1. We conclude that galaxy central densities may not be as problematic for the CDM paradigm as is sometimes assumed: rather than telling us something about the nature of the dark matter, galaxy rotation curves may be telling us something about inflation and/or neutrinos. An important test of this idea will be an eventual consensus on the value of sigma_8, the rms overdensity on the scale 8 h^-1 Mpc. Our successful models have values of sigma_8 approximately 0.75, which is within the range of recent determinations. Finally, models with n>1 (or sigma_8 > 1) are highly disfavored.Comment: 13 pages, 6 figures. Minor changes made to reflect referee's Comments, error in Eq. (18) corrected, references updated and corrected, conclusions unchanged. Version accepted for publication in Phys. Rev. D, scheduled for 15 August 200

Level of satisfaction of online classes by students of Physical Education of Chile in times of pandemic

Indexación ScopusEn Chile el primer caso de COVID-19 fue diagnosticado el tres de marzo del 2020 y el día dieciocho del mismo mes el presidente decreto estado de catástrofe, por lo que las clases a nivel escolar y universitario pasaron de la presencialidad a la virtualidad. El presente estudio tiene como objetivo conocer el nivel de satisfacción de las clases virtuales de los estudiantes de Educación Física. Metodología: Cuantitativa, no experimental, transversal. La muestra estuvo constituida por 542 alumnos de Educación Física de diferentes casas de estudio de Chile. Se adaptó y validó la escala Satisfacción clases online. Resultados: existen diferencias significativas comparando las asignaturas teóricas y prácticas, siendo mejor valoradas las cátedras teóricas. También se encontraron diferencias por sexo, donde los varones poseen una percepción más negativa sobre las clases virtuales y al comparar por curso, los alumnos de primer año poseen una percepción más positiva sobre las clases virtuales en relación con los cursos superiores. Conclusiones: existe una resistencia por parte de los alumnos a las clases virtuales en la Educación Física, pues, si bien se encontraron diferencias significativas entre las asignaturas teóricas y prácticas, los valores siempre estuvieron alrededor de 3 en una escala de 1 a 5. Se hacen necesarias futuras investigaciones con otras variables como actividad física, niveles de estrés y estrategias para la enseñanza de la Educación Física virtual.In Chile the first case of COVID-19 was diagnosed on March 3, 2020 and on the eighteenth of the same month the president decreed state of catastrophe, so that classes at school and university level went from the presence to the virtuality. The present study aims to know the level of satisfaction of the virtual classes of the students of Physical Education. Methodology: Quantitative, non experimental, transversal. The sample consisted of 542 students of Physical Education from different study houses in Chile. The Satisfaction scale online classes was adapted and validated. Results: there are significant differences comparing theoretical and practical subjects, with theoretical chairs being better valued. Differences were also found by sex, where males have a more negative perception about virtual classes and when comparing by course, freshmen have a more positive perception about virtual classes in relation to higher courses. Conclusions: there is a resistance on the part of students to virtual classes in Physical Education, because, although significant differences were found between the theoretical and practical subjects, values were always around 3 on a scale of 1 to 5. Future research with other variables such as physical activity, stress levels and strategies for the teaching of Virtual Physical Education are necessary.https://recyt-fecyt-es.recursosbiblioteca.unab.cl/index.php/retos/article/view/8290

In situ degradability of corn stover and elephant-grass harvested at four stages of maturity

Among tropical forages, corn silage is largely used by farmers trying to explore the maximum genetic potential from the animals. However, other tropical forages, such as elephant-grass (Pennisetum purpureum), are more productive and therefore cheaper to use than corn silage. Our objective was to compare the in situ degradability of elephant-grass with that from corn hybrids, all harvested at four stages of maturity. The experimental design followed a randomized block design with nested subplots. Two corn hybrids: AG5011, ZN8392 were harvested with 25, 30, 35, and 40% dry matter (DM) in the whole plant, and separated in stem + leaf sheath + leaf blade (stover), and cobs. Elephant-grass was harvested with 30, 40, 50 and 60 days after a leveling cut. Dried and ground samples were incubated in nylon bags inside the rumen for 0, 6, 12, 24, 48 and 72 h to estimate the kinetics of ruminal DM and neutral detergent fiber (NDF) degradation. The advance of maturity increased the NDF and acid detergent fiber (ADF) content in elephant-grass, and reduced its DM degradability. However, maturity had little or no effect on fiber content and DM degradability of corn stover. Elephant-grass had a higher NDF degradability than corn stover, and there was no effect of maturity on NDF degradability of either elephant-grass or corn stover. Fiber degradability of elephant-grass was not worse than that of corn stover, and therefore the choice of forage should be made on economical analysis rather than assuming an intrinsic low production potential for elephant-grass based diets.Dentre as forragens, a silagem de milho é amplamente utilizada pelos fazendeiros que visam explorar o máximo do potencial genético dos animais. No entanto, outros volumosos tropicais como o capim-elefante (Pennisetum purpureum) são mais produtivos e, portanto, mais baratos do que a silagem de milho. Nosso objetivo foi comparar a degradabilidade in situ do capim-elefante com a degradabilidade de híbridos de milho, colhidos em quatro estágios de maturidade. O experimento seguiu um delineamento de blocos ao acaso com sub-parcelas. Dois híbridos de milho: AG5011 e ZN8392 foram colhidos com 25, 30, 35 e 40% matéria seca (MS) na planta toda e separados na fração colmo + bainha + folhas e espigas. Capim elefante foi colhido 30, 40, 50 e 60 dias após o corte de nivelamento. As amostras secas e trituradas foram incubadas no rúmen por 0, 6, 12, 24, 48 e 72 h para cálculo da cinética da degradação ruminal da MS e da fibra em detergente neutro (FDN). O avanço da maturidade aumentou os teores de FDN e fibra em detergente ácido (FDA) do capim elefante e reduziu a degradabilidade da MS. Entretanto, a maturidade teve pouco efeito sobre os teores de fibra e a degradabilidade da MS da fração planta dos híbridos de milho. O capim elefante apresentou maior degradabilidade da FDN do que híbridos de milho, e não houve efeito da maturidade sobre a degradabilidade da FDN das duas espécies. A degradabilidade da fibra de capim-elefante não é pior do que a de híbridos de milho e, portanto a escolha da forragem deve ser feita com base em análises econômicas ao invés de assumir um menor potencial de produção em dietas a base de capim elefante