Estrés y funcionamiento cognitivo en universitarios / Stress and cognitive functioning in undergraduate students

La presente investigación corresponde a un estudio de tipo no experimental, transversal, descriptivo y correlacional en el que se evaluaron niveles de estrés, estrategias de afrontamiento, manifestaciones físicas y psicológicas por estrés, hábitos de sueño y alimentación, consumo de tabaco y alcohol, y funcionamiento cognitivo en 50 estudiantes universitarios durante el período de exámenes de fin de semestre académico, con objetivo de determinar la relación entre variables ya que en la literatura se reporta que el estrés es considerado un factor de riesgo, y la exposición continua puede afectar funciones cognitivas. Los participantes reportaron niveles medios o bajos de estrés percibido, uso moderado de estrategias adecuadas e inadecuadas y no se halló correlación entre estrés y funcionamiento cognitivo, concluyendo que el estrés debido a exámenes no es suficientemente intenso, la muestra posee adecuado manejo del mismo y se requieren más estudios para validar y estandarizar la prueba MoCA en población general colombiana.

This research correspond to a non-experimental, cross-sectional, descriptive and correlational study in which stress levels, coping strategies, physical and psychological manifestations due to stress, sleeping and eating habits, tobacco and alcohol consumption, and cognitive functioning were evaluated in 50 undergraduate students during the period of exam at the end of the semester, in order to determine the relationship between variables since in the literature it is reported that stress is considered a risk factor, and continuous exposure can affect cognitive functions. Participants reported medium or low levels of perceived stress, moderate use of appropriate and inappropriate strategies and no correlation was found between stress and cognitive functioning, concluding that stress due to exams is not intense enough, the sample has adequate handling of it, and more studies are required to validate and standardize the MoCA test in the general population of Colombia.

Estrés y deterioro cognitivo en pacientes con diagnóstico de esquizofrenia / Stress and cognitive impairment in patients with diagnosis of schizophrenia

El presente es un estudio no experimental, transversal y correlacional, cuyo objetivo era determinar si existe relación entre estrés y deterioro cognitivo en personas con diagnóstico de esquizofrenia, confirmar si la depresión y las estrategias de afrontamiento del estrés se relacionan y si son factores moderadores de la relación entre estrés y deterioro cognitivo, mediante la evaluación y descripción del estrés percibido (PSS), estrategias de afrontamiento del estrés (CSI), depresión (CDSS) y deterioro cognitivo (MoCA), en una muestra de 43 pacientes con diagnóstico de esquizofrenia (36 hombres y 7 mujeres) entre los 16 y 65 años, de Bucaramanga y Medellín (Colombia), seleccionados mediante muestreo no probabilístico por conveniencia. Se encontró que el grupo presenta niveles medios de estrés percibido y puntuaciones medias y bajas en estrategias de afrontamiento adecuadas e inadecuadas, casi la mitad presenta riesgo de comorbilidad con depresión y la mayoría presenta deterioro cognitivo. No se encontró relación entre deterioro cognitivo con las demás variables. Estrés se relaciona significativamente con depresión y con estrategias de afrontamiento expresión emocional, retirada social y autocrítica. Finalmente, depresión correlacionó significativamente con estrategias de afrontamiento expresión emocional y retirada social. Aunque estos hallazgos no pueden ser concluyentes ni generalizables debido a limitaciones metodológicas, pueden ser usados como antecedente para futuros estudios.

The present is a non-experimental, cross-sectional and correlational study, whose objective was to determine if there is a relationship between stress and cognitive impairment in people diagnosed with schizophrenia, to confirm whether depression and coping strategies are related and if they are moderating factors of the relationship between stress and cognitive impairment, through the evaluation and description of perceived stress (PSS), stress coping strategies (CSI), depression (CDSS) and cognitive impairment (MoCA), in a sample of 43 patients diagnosed with schizophrenia (36 men and 7 women) between 16 and 65 years old, from Bucaramanga and Medellín (Colombia), selected by non-probabilistic for convenience sampling. It was found that the group in average presents a medium level of perceived stress, and average and low scores in appropriate and inadequate coping strategies, almost half presents risk of comorbidity with depression, and most of them present cognitive impairment. No relationship was found between cognitive impairment with the other variables. Stress is significantly related to depression and coping strategies as emotional expression, social withdrawal and self-criticism. Finally, depression correlated significantly with coping strategies as emotional expression and social withdrawal. Although these findings cannot be conclusive or generalizable due to methodological limitations, they can be used as a precedent for future studies.

Aspectos psicosociales del rol docente en la modalidad B-Learning de la Universidad Militar Nueva Granada / Psychosocial Features of Teacher's Role in B-Learning Modality at Universidad Militar Nueva Granada

Resumen Los cambios en la educación superior vienen en parte precedidos por el impacto de las tecnologías de la información y la comunicación, cuya incidencia se refleja en el cambio de roles del docente. Por consiguiente, en las modalidades b-learning se tiene que los docentes adquieren nuevos papeles, producto de la influencia social en el quehacer profesional desde las instituciones educativas y la sociedad en general. De lo anterior, se articula el enfoque de las representaciones sociales para caracterizar el conjunto de pensamientos cotidianos de los docentes de la Facultad de Estudios a Distancia, encontrando que los roles de facilitador, guía y acompañante adquieren preponderancia en la acción pedagógica del docente a manera de aspectos centrales de la representación.

Abstract Changes in higher education come in part preceded by the impact of the technologies of information and communication, whose incidence is reflected in the change of teacher's roles. Therefore, in b-learning modalities teachers must acquire new roles, which are the product of social influence in professional activities from educational institutions and society, in general. Otherwise, the approach of social representations to characterize the set of everyday thoughts of teachers in the Faculty of Distance Studies is articulated, finding out that the roles of a facilitator, a guide, and a companion acquire significance in the pedagogical action of the teaching as a way of key aspects of the representation.

Equilibrium transitions between side-chain conformations in leucine and isoleucine.

Despite recent improvements in computational methods for protein design, we still lack a quantitative, predictive understanding of the intrinsic probabilities for amino acids to adopt particular side-chain conformations. Surprisingly, this question has remained unsettled for many years, in part because of inconsistent results from different experimental approaches. To explicitly determine the relative populations of different side-chain dihedral angles, we performed all-atom hard-sphere Langevin Dynamics simulations of leucine (Leu) and isoleucine (Ile) dipeptide mimetics with stereo-chemical constraints and repulsive-only steric interactions between non-bonded atoms. We determine the relative populations of the different χ(1) and χ(2) dihedral angle combinations as a function of the backbone dihedral angles ϕ and ψ. We also propose, and test, a mechanism for inter-conversion between the different side-chain conformations. Specifically, we discover that some of the transitions between side-chain dihedral angle combinations are very frequent, whereas others are orders of magnitude less frequent, because they require rare coordinated motions to avoid steric clashes. For example, to transition between different values of χ(2), the Leu side-chain bond angles κ(1) and κ(2) must increase, whereas to transition in χ(1), the Ile bond angles λ(1) and λ(2) must increase. These results emphasize the importance of computational approaches in stimulating further experimental studies of the conformations of side-chains in proteins. Moreover, our studies emphasize the power of simple steric models to inform our understanding of protein structure, dynamics, and design.

Protein design: Past, present, and future.

Building on the pioneering work of Ho and DeGrado (J Am Chem Soc 1987, 109, 6751-6758) in the late 1980s, protein design approaches have revealed many fundamental features of protein structure and stability. We are now in the era that the early work presaged - the design of new proteins with practical applications and uses. Here we briefly survey some past milestones in protein design, in addition to highlighting recent progress and future aspirations.

Intrinsic α-helical and ß-sheet conformational preferences: a computational case study of alanine.

A fundamental question in protein science is what is the intrinsic propensity for an amino acid to be in an α-helix, ß-sheet, or other backbone dihedral angle ( ϕ-ψ) conformation. This question has been hotly debated for many years because including all protein crystal structures from the protein database, increases the probabilities for α-helical structures, while experiments on small peptides observe that ß-sheet-like conformations predominate. We perform molecular dynamics (MD) simulations of a hard-sphere model for Ala dipeptide mimetics that includes steric interactions between nonbonded atoms and bond length and angle constraints with the goal of evaluating the role of steric interactions in determining protein backbone conformational preferences. We find four key results. For the hard-sphere MD simulations, we show that (1) ß-sheet structures are roughly three and half times more probable than α-helical structures, (2) transitions between α-helix and ß-sheet structures only occur when the backbone bond angle τ (NCα C) is greater than 110°, and (3) the probability distribution of τ for Ala conformations in the "bridge" region of ϕ-ψ space is shifted to larger angles compared to other regions. In contrast, (4) the distributions obtained from Amber and CHARMM MD simulations in the bridge regions are broader and have increased τ compared to those for hard sphere simulations and from high-resolution protein crystal structures. Our results emphasize the importance of hard-sphere interactions and local stereochemical constraints that yield strong correlations between ϕ-ψ conformations and τ.

Activación sónica versus ultrasónica de EDTA al 10% para remoción de barrillo dentinario en el tercio apical del canal radicular / Sonic versus ultrasonic activation of 10% EDTA for smear layer removal in the root canal apical third

El objetivo de este estudio fue evaluar la efectividad de la activación sónica y ultrasónica del ácido etilendiaminotetraacético (EDTA) al 10% para remover barrillo dentinario en el tercio apical y el grado de erosión producido sobre las paredes del canal radicular. Se realizó un estudio cuantitativo experimental in vitro. Se instrumentaron 40 dientes manualmente con la técnica step-back hasta lima maestra número 55 y fueron asignados a 4 grupos según protocolo de irrigación final: I: agua destilada estéril sin activación, II: EDTA 10% sin activación por 30 segundos, III: EDTA 10% activado sónicamente por 30 segundos y IV: EDTA 10% activado ultrasónicamente por 30 segundos. Las muestras fueron observadas en MEB a una magnificación de 5000X. Se evaluó la presencia de barrillo dentinario remanente y grado de erosión según criterios de Torabinejad et al. Para el análisis estadístico se utilizó la prueba de Kruskal-Wallis y Post Hoc de Tukey con un nivel de significancia 5% (p=0,05). El grupo I (agua sin activación) presentó mayor cantidad de barrillo que el resto de los grupos (p<0,01). En cuanto a la presencia de barrillo, entre los grupos II (EDTA sin activación), III (EDTA con sonido) y IV (EDTA con ultrasonido) no hubo diferencias estadísticamente significativas. En cuanto a la erosión, el grupo II presentó una mayor erosión que el resto siendo significativa con los grupos I y III (p=0,006). Entre los grupos I, III y IV no hubo diferencias estadísticamente significativas. La activación sónica y ultrasónica del EDTA 10% no produjo una remoción de barrillo significativamente superior al compararlo con la irrigación convencional, pero sí hubo diferencias en cuanto a erosión, siendo menor con la activación sónica

The purpose of this study was to observe the effect of passive sonic and ultrasonic irrigation with 10% Ethilenediaminotetracethic acid (EDTA) on smear layer of the apical third of instrumented root canals as well as the level of erosion produced on the canal walls. For this quantitative experimental in vitro study 40 teeth were hand instrumented with step back technique until master file num 55 and divided in four groups according to the final irrigation protocol: I: distilled water without activation, II: 10% EDTA for 30 seconds without activation, III: 10% EDTA sonic activated for 30 seconds, IV: 10% EDTA ultrasonic activated for 30 seconds. Samples were prepared for MEB observation at 5000X. The presence of smear layer and erosion on dentine walls was quantified according to Torabinejad et al. criteria. Data were submitted at Kruskal-Wallis test and Tukey Post Hoc with a significance level of 5% (P=0.05). When evaluating the smear layer presence, there were no statistically significant differences between the groups II, III and IV. Group I had a highest amount of smear layer (p<0.01). As for erosion, group II showed higher erosion than the others, being significant with groups I and III (p=0.006). Among groups I, III and IV there were not statistically significant differences. Sonic and ultrasonic activation of EDTA 10% did not produce a significantly superior removal of smear layer when compared with conventional irrigation. Erosion of root canal walls was significantly lower after sonic activation

New insights into the interdependence between amino acid stereochemistry and protein structure.

To successfully design new proteins and understand the effects of mutations in natural proteins, we must understand the geometric and physicochemical principles underlying protein structure. The side chains of amino acids in peptides and proteins adopt specific dihedral angle combinations; however, we still do not have a fundamental quantitative understanding of why some side-chain dihedral angle combinations are highly populated and others are not. Here we employ a hard-sphere plus stereochemical constraint model of dipeptide mimetics to enumerate the side-chain dihedral angles of leucine (Leu) and isoleucine (Ile), and identify those conformations that are sterically allowed versus those that are not as a function of the backbone dihedral angles ϕ and ψ. We compare our results with the observed distributions of side-chain dihedral angles in proteins of known structure. With the hard-sphere plus stereochemical constraint model, we obtain agreement between the model predictions and the observed side-chain dihedral angle distributions for Leu and Ile. These results quantify the extent to which local, geometrical constraints determine protein side-chain conformations.

Memoria declarativa congruente con sintomatología depresiva / Consistent declarative memory with depressive symptomatology

Introducción: Algunos estudios han sugerido que el recuerdo potenciado de eventos negativos en personas que presentan trastornos depresivos parece ser un factor importante en la Etiología, curso y sostenimiento de la depresión. Objetivo: Evaluar la memoria emocional en Personas con y sin sintomatología depresiva, mediante una prueba auditivo-visual. Método: Se evaluaron 73 estudiantes universitarios, hombres y mujeres, con edades entre los 18 y 40 años, distribuidos en dos grupos: con sintomatología depresiva (32) y sin sintomatología Depresiva (40), utilizando la Escala del Centro de Estudios Epidemiológicos para Depresión(CES-D) y un punto de corte de 20. Resultados: No se encontraron diferencias significativas Entre el recuerdo libre de los voluntarios con y sin sintomatología depresiva, a pesar de que Ambos asignaron un valor emocional más alto a la versión emocional de la prueba auditivo-Visual y de asociarla a la emoción de tristeza. Conclusión: Las personas con sintomatología Depresiva no presentaron el efecto de potenciación mnemónica generalmente asociado al Contenido de la versión emocional de la prueba; por lo tanto, no se comprobó la hipótesis De congruencia emocional...

Introduction: Some studies have suggested that potentiated remembrance of negative events on people with depressive disorders seems to be an important factor in the etiology, course and maintenance of depression. Objective: Evaluate the emotional memory in people with and without depressive symptomatology by means of an audio-visual test. Methodology: 73 university students were evaluated, male and female, between 18 and 40 years old, distributed in two groups: with depressive symptomatology (32) and without depres-sive symptomatology (40), using the Scale from the Center of Epidemiologic Studies for Depression (CES-D, English Abbreviation) and a cutting point of 20. Results: There were not meaningful differences between free and voluntary recalls, with and without depressive symptomatology, in spite of the fact that both groups had granted a higher emotional value to the audio-visual test and that they had associated it with emotional sadness. Conclusion: People with depressive symptomatology did not exhibit the effect of mnemonic potentiation generally associated to the content of the emotional version of the test; therefore, the hypothesis of emotional consistency was not validated...

[Consistent Declarative Memory with Depressive Symptomatology]. / Memoria declarativa congruente con sintomatología depresiva.

INTRODUCTION: Some studies have suggested that potentiated remembrance of negative events on people with depressive disorders seems to be an important factor in the etiology, course and maintenance of depression. OBJECTIVE: Evaluate the emotional memory in people with and without depressive symptomatology by means of an audio-visual test. METHODOLOGY: 73 university students were evaluated, male and female, between 18 and 40 years old, distributed in two groups: with depressive symptomatology (32) and without depressive symptomatology (40), using the Scale from the Center of Epidemiologic Studies for Depression (CES-D, English Abbreviation) and a cutting point of 20. RESULTS: There were not meaningful differences between free and voluntary recalls, with and without depressive symptomatology, in spite of the fact that both groups had granted a higher emotional value to the audio-visual test and that they had associated it with emotional sadness. CONCLUSION: People with depressive symptomatology did not exhibit the effect of mnemonic potentiation generally associated to the content of the emotional version of the test; therefore, the hypothesis of emotional consistency was not validated.