Pitfalls and challenges of peptide nucleic acid immobilisation on carbon surfaces for sequence-specific capturing of nucleic acid biomarkers.

Nucleic acid sensors based on a peptide nucleic acid (PNA) probe have seen a surge in interest since their discovery in the 1990s, and after the patent protecting them expired in 2013. The appeal of PNA as capture and/or sensing probes as an alternative to standard DNA or RNA oligonucleotides originates from their superior chemical stability and affinity for complementary oligonucleotides, as well as their increased responsiveness to single base mismatches. The implementation of PNA probes onto optical and electrochemical sensors has showed great promise although progress has been hampered by issues mostly associated with surface chemistry, probe accessibility and non-specific binding. Herein, we report on a systematic comparison between various PNA immobilisation strategies on carbon substrates based on both covalent and non-covalent chemistries. Besides the use of standard electrochemical techniques to characterise the extent of surface modification, the ability of immobilised PNAs to engage in chemical interactions with freely diffusing molecules was also investigated. Using original chemical tags, this study provides a unique insight into the impact of immobilisation chemistries on PNA's (bio)availability. Rapid immobilisation of biotinylated PNA oligomers on screen-printed carbon electrode (SPCE) coated with adsorbed polystreptavidin (pSA) demonstrated highest efficiency and ease in the preparation process. An original nucleic acid sensor using this immobilisation chemistry is reported that is based on a sandwich assay between a surface bound PNA capture probe and a freely diffusing electrochemically active PNA sensing probe.

Analysis of the teaching effect of the normal human morphology with mixed teaching mode and formative evaluation in China / Análisis del efecto de la enseñanza de morfología humana normal con un modelo de enseñanza mixta y evaluación formativa en China

With the accumulation of teaching experience and the summary of the teaching process in the teaching of medical colleges and universities, the course "Normal Human Morphology" has been basically on the right track in undergraduate education. However, most of the colleges and universities in China still use the traditional teaching mode, and the evaluation of students' learning effects and teacher teaching still follows the method of final evaluation. This method is not conducive to students' timely understanding of self-stage learning effects. It will affect the teacher's adjustment (or solution) to the specific links (or problems) that appear in the teaching process. The establishment of the mixed teaching model and formative evaluation system can solve the problems of the two to some extent.

Con la mayor experiencia de los docentes y del proceso de aprendizaje en la enseñanza de facultades y universidades de medicina, el curso "Morfología Humana Normal" básicamente ha seguido una metodología correcta en la educación de pregrado. Sin embargo, la mayoría de los colegios y universidades en China aún utilizan el modelo de enseñanza tradicional, por lo cual, la evaluación de los efectos de aprendizaje de los estudiantes junto con la enseñanza docente, a la fecha, sigue el método de una evaluación final. Este método no es propicio para la comprensión oportuna por parte de los alumnos, en la etapa del auto-aprendizaje, ya que afecta la adaptación (o solución) del profesor a los enlaces (o problemas) específicos que aparecen en el proceso de enseñanza. El establecimiento de un modelo de enseñanza mixta y un sistema de evaluación formativa en cierta medida podrían resolver ambos problemas.

The application of barrier-based learning (BBL) method in histology learning from China / La aplicación del método de aprendizaje basado en barreras (BBL) en el aprendizaje de histología en China

Histology belongs to the discipline of medical morphology. The knowledge is scattered and abstract in this discipline. It is difficult to the medical students beginner. Leading to poor effect on histology teaching. This study aimed to introduce medical students to the histology using barrier-based learning (BBL) method or traditional teaching method. We recruited 4 clinical medical classes, including two 5-years classes and two 7-years clinical medical classes, each of these classes randomly assigned to 1 of 2 groups. The control group received an introductory traditional teaching mode in histology. The experiment group received BBL method. Using final exam average scores, pass rate, excellent rates and phase tests to evaluate the teaching effect of these two teaching method. BBL teaching method is more effective than traditional teaching method, The application of BBL in histology is more easier to learning for the beginners of medical students.

La histología es una disciplina de la morfología médica. El conocimiento es disperso y abstracto en esta disciplina. Es una asignatura que resulta difícil para los estudiantes principiantes de medicina. Este estudio tuvo como objetivo presentar a los estudiantes de medicina la histología mediante el método de aprendizaje basado en barreras (BBL), comparándolo al método de enseñanza tradicional. Reclutamos estudiantes de 4 clases de medicina clínica, incluidas dos clases de quinto año y dos clases de medicina clínica de séptimo año, cada una de estas clases asignadas al azar a los grupos. El grupo de control recibió un método de enseñanza tradicional de introducción en histología. El grupo experimental recibió el método BBL. Usando los puntajes promedio del examen final, la tasa de aprobación, las tasas de excelencia y las pruebas de fase para evaluar el efecto de enseñanza de estos dos métodos de enseñanza, se determinó que el método de enseñanza de BBL es más efectivo que el método de enseñanza tradicional. La aplicación de BBL en histología permite un aprendizaje más sencillo para los estudiantes principiantes de medicina.