The kisspeptin-GnRH pathway in human reproductive health and disease

BACKGROUND: The discovery of kisspeptin as key central regulator of GnRH secretion has led to a new level of understanding of the neuroendocrine regulation of human reproduction. The related discovery of the kisspeptin-neurokinin B-dynorphin (KNDy) pathway in the last decade has further strengthened our understanding of the modulation of GnRH secretion by endocrine, metabolic and environmental inputs. In this review, we summarize current understanding of the physiological roles of these novel neuropeptides, and discuss the clinical relevance of these discoveries and their potential translational applications. METHODS: A systematic literature search was performed using PUBMED for all English language articles up to January 2014. In addition, the reference lists of all relevant original research articles and reviews were examined. This review focuses mainly on published human studies but also draws on relevant animal data. RESULTS: Kisspeptin is a principal regulator of the secretion of gonadotrophins, and through this key role it is critical for the onset of puberty, the regulation of sex steroid-mediated feedback and the control of adult fertility. Although there is some sexual dimorphism, both neuroanatomically and functionally, these functions are apparent in both men and women. Kisspeptin acts upstream of GnRH and, following paracrine stimulatory and inhibitory inputs from neurokinin B and dynorphin (KNDy neuropeptides), signals directly to GnRH neurones to control pulsatile GnRH release. When administered to humans in different isoforms, routes and doses, kisspeptin robustly stimulates LH secretion and LH pulse frequency. Manipulation of the KNDy system is currently the focus of translational research with the possibility of future clinical application to regulate LH pulsatility, increasing gonadal sex steroid secretion in reproductive disorders characterized by decreased LH pulsatility, including hypothalamic amenorrhoea and hypogonadotropic hypogonadism. Conversely there may be scope to reduce the activity of the KNDy system to reduce LH secretion where hypersecretion of LH adds to the phenotype, such as in polycystic ovary syndrome. CONCLUSIONS: Kisspeptin is a recently discovered neuromodulator that controls GnRH secretion mediating endocrine and metabolic inputs to the regulation of human reproduction. Manipulation of kisspeptin signalling has the potential for novel therapies in patients with pathologically low or high LH pulsatility

Framework para evaluar la usabilidad sistemas M-Learning: un enfoque tecnológico y pedagógico

Esta tesis se ha centrado en proponer un framework para evaluar la usabilidad de aplicaciones m-learning. Para ello, en primer lugar se realizó un análisis del estado actual de las investigaciones en el ámbito del aprendizaje móvil (m-learning), la usabilidad en dispositivos móviles, así como las propuestas que abordan ambos aspectos de forma conjunta, aplicando la metodología de mapeo sistemático de la literatura. El objetivo de esta revisión ha sido conocer las tendencias y las necesidades existentes dentro del campo del diseño y evaluación de aplicaciones m-learning. Los resultados muestran que la investigación en esta área se ha incrementado significativamente a partir del año 2013, y dado el creciente auge de los dispositivos móviles en la educación, se cree que el número de publicaciones seguirá en aumento en los próximos años. Se identificaron los principales enfoques que adoptan los diferentes trabajos analizados; así como los dispositivos móviles y sistemas operativos más utilizados. También se detectó que no todas las aplicaciones m-learning analizadas incluían pruebas de usabilidad, ni se encontraron guidelines o frameworks que permitieran evaluarlas. Ante tal necesidad, se propuso un framework conceptual para evaluar aplicaciones m-learning, considerando aspectos pedagógicos y de usabilidad en dispositivos móviles. Dicho framework está dividido en dos categorías, que corresponden con las fases de evaluación de la usabilidad pedagógica y de la usabilidad de interfaz de usuario o tecnológica, respectivamente. Adicionalmente, se propone una metodología para desarrollar aplicaciones m-learning centradas en el estudiante, la cual considera los elementos del framework propuesto, durante las fases de desarrollo y de evaluación. Además, se ha creado un instrumento de medición y una herramienta software para facilitar la evaluación de este tipo de aplicaciones. Dicho instrumento es un cuestionario fiable y válido que incluye ítems relacionados con los elementos incluidos en el framework propuesto. La herramienta desarrollada tiene como base dicho cuestionario, permite enviarlo a los evaluadores para que lo contesten en línea, y presenta resultados gráficos y estadísticos de las evaluaciones realizadas. Las aportaciones realizadas en esta tesis pretenden dotar, a los docentes y desarrolladores de aplicaciones m-learning, de recursos que les guíen a la hora de diseñar, implementar y evaluar este tipo de aplicaciones, con el fin último de favorecer la obtención de aplicaciones más usables y que mejoren la experiencia de aprendizaje de los estudiantes

Characteristics of a Persuasive Educational System: A Systematic Literature Review

The need to compete for users’ attention and provide them with the best user experience has increased the use of persuasion strategies in modern systems. Currently, Persuasive Systems (PSs) promote healthy behavior for well-being, energy consumption, and learning. Although the educational domain has limited investigation compared to other areas, PSs in education have been shown to be effective in motivating students. This paper summarizes the existing evidence on Persuasive Educational Systems (PESs), emphasizing research on the current design methods, evaluation methods, and characteristics. We follow Kitchenham’s method to perform a systematic literature review about PESs published between 2014 and 2020, with 19 relevant studies selected. We highlight some results from the analysis of selected papers such as persuasion strategies, use of a personalized persuasion technique, study of students’ susceptibility to strategies, integration of gamification mechanisms, and proposed tools to design PES. Moreover, we discuss interesting facts such as the common practice of using more than one tool to design PES, aspects of interaction, persuasion, learning, and the challenges in evaluating persuasive impact. Finally, as the main contribution of the paper we identify the seven necessary characteristics to build a persuasive educational system

Nyquist-Shannon theorem application for Savitzky-Golay smoothing window size parameter determination in bio-optical signals

The amount of data generated in the laboratory increases constantly, where a common problem needed to be addressed during the data preparation stage is related to noise. The Savitzky-Golay method has been established as the common smoothing technique, where the process is based on two parameters: polynomial order and window size, which are commonly empirically determined. This work shows how the application of the Nyquist theorem allows to calculate the window size parameter of the Savitzky-Golay smoothing method, in order to process bio-optical signals. Like in the case of mid-IR glucose absorption and cervical spine X-ray images, from which a derivative based analysis allows to either confirm or determine regions of interest for further study