Force reconstruction from tapping mode force microscopy experiments

Fast, accurate, and robust nanomechanical measurements are intensely studied in materials science, applied physics, and molecular biology. Amplitude modulation force microscopy (tapping mode) is the most established nanoscale characterization technique of surfaces for air and liquid environments. However, its quantitative capabilities lag behind its high spatial resolution and robustness. We develop a general method to transform the observables into quantitative force measurements. The force reconstruction algorithm has been deduced on the assumption that the observables (amplitude and phase shift) are slowly varying functions of the tip–surface separation. The accuracy and applicability of the method is validated by numerical simulations and experiments. The method is valid for liquid and air environments, small and large free amplitudes, compliant and rigid materials, and conservative and non-conservative forces.This work was funded by the Spanish Ministry of Economy (MINECO) through grant CSD2010–00024 and the European Research Council ERC-AdG-340177 (3DNanoMech)

Post-treatment Apical Periodontitis in Primary Non-surgical Root Canal Treatment: A Multiple Correspondence Analysis

Introduction: The presented study aimed to characterise periapical disease in teeth with primary non-surgical root canal treatment in persistent or emergent categories and their risk association. Methods: A retrospective observational study that evaluated permanent teeth with primary non-surgical root canal treatment, was conducted clinically and radiographically for over one year. The following variables were analysed: gender, age, type and location of tooth, previous diagnosis, treatment conditions, and type of coronal restoration. The supplementary variables included the perspectives of the treatment outcome, such as Remains normal, Improvement, and Failure. Statistical analysis was performed using a univariate analysis that estimated the average and proportion for each factor according to the result of the primary non-surgical root canal treatment. The multiple correspondence analysis identified the hierarchy between active variables and their association with the results. Results: A total of 232 teeth in 155 participants were analysed. A χ2 value, (P=0.023) showed that the emergent disease is associated with patients around the age of 50. The multiple correspondence analysis identified a tendency of grouping between the emergent disease and the short filling category, followed by symptomatic pulpitis as a previous diagnosis. The persistent disease was associated with errors and overfillings. An inadequate root filling and taper density adversely impacted the treatment outcome. Conclusions: The length of obturation influenced the presence of failure. Short fillings were associated with emerging periapical disease. Errors and overfillings contributed to the persistent disease in the populations studied

Vertical Jumping as a Monitoring Tool in Endurance Runners: A Brief Review

Jumping performance (e.g., countermovement jump [CMJ]), as a measure of neuromuscular performance, has been suggested as an easy-to-use tool which simultaneously provides neuromuscular and metabolic information and, thereby, allows coaches to confidently monitor the status of their athletes during a workout. This hypothesis has been satisfactorily tested with sprint athletes. However, the rationale for the use of CMJ height loss as an index to monitor the workload during an endurance running session is not sufficiently evidence-based. First, it is assumed that a CMJ height loss occurs during typical interval training for endurance runners. Second, it is also assumed that a significant relationship between metabolic stress and the neuromuscular strain induced during these endurance workouts exists. These two assumptions will be questioned in this review by critically analyzing the kinetics of CMJ performance during and after running workouts, and the relationship between neuromuscular and physiological stress induced during different protocols in endurance runners. The current evidence shows that fatigue induced by common running workouts for endurance runners does not counterbalance the potentiation effect in the CMJ height. Additionally, the findings reported among different studies are consistent regarding the lack of association between CMJ height loss and physiological stress during interval sessions in endurance runners. In practical terms, the authors suggest that this marker of neuromuscular fatigue may not be used to regulate the external training load during running workouts in endurance runners. Nevertheless, the analysis of CMJ height during running workouts may serve to monitor chronic adaptations to training in endurance runners

H-2Ld class I molecule protects an HIV N-extended epitope from in vitro trimming by endoplasmic reticulum aminopeptidase associated with antigen processing.

In the classical MHC class I Ag presentation pathway, antigenic peptides derived from viral proteins by multiple proteolytic cleavages are transported to the endoplasmic reticulum lumen and are then exposed to ami-nopeptidase activity. In the current study, a long MHC class I natural ligand recognized by cytotoxic T lymphocytes was used to study the kinetics of degradation by aminopeptidase. The in vitro data indicate that this N-extended peptide is efficiently trimmed to a 9-mer, unless its binding to the MHC molecules protects the full-length peptide.We thank Dr. A. K. Stout of the NIH Tetramer Facility for providing the peptide/MHC complex reagent. This work was suppor ted by grants provi ded by Programa Ramón y Cajal, and Fundación FIPSE to D. L.; by grants provided by Comunidad de Madrid and Ministerio de Educación y Ciencia to M. D. V.; and by a joint grant provided by Instituto de Salud Carlos III to D. L., and M. D. V.S

INVESTIGACIÓN EN QUÍMICA, BIOLOGÍA Y AGRONOMÍA

Este libro es el segundo de una serie de dos dedicado a los avances lo relativo a las mezclas de diesel y biodiesel obtenido a partir del aceite de semillas de jatropha curcas, entre otros temas de ese ombustible verde; es decir algo que está al día en cuanto a las búsqueda de fuentes de energía limpias; otro tema ampliamente tratado es el del nitrógeno como elemento de fertilización -que junto con la densidad poblacional de las plantas- buscan prácticas agronómicas para obtener mayores rendimientos. El objetivo final de este libro es el mismo: incorporar cada vez más bibliografía que enriquezca las opciones de consulta por parte de interesados en aspectos particulares y, desde luego, divulgar nuevos conocimentos y ofrecer los resultados del quehacer universitario

Provisos for classic linear oscillator design methods. New linear oscillator design based on the NDF/RRT

In this paper, the classic oscillator design methods are reviewed, and their strengths and weaknesses are shown. Provisos for avoiding the misuse of classic methods are also proposed. If the required provisos are satisfied, the solutions provided by the classic methods (oscillator start-up linear approximation) will be correct. The provisos verification needs to use the NDF (Network Determinant Function). The use of the NDF or the most suitable RRT (Return Relation Transponse), which is directly related to the NDF, as a tool to analyze oscillators leads to a new oscillator design method. The RRT is the "true" loop-gain of oscillators. The use of the new method is demonstrated with examples. Finally, a comparison of NDF/RRT results with the HB (Harmonic Balance) simulation and practical implementation measurements prove the universal use of the new methods

Análisis de las mejoras competitivas del nuevo programa de verificación vehicular de la Megalópolis de la Ciudad de México.

Capitulo de libroEn el presente trabajo, se analizan las características técnicas y tecnológicas que se emplean para realizar la verificación vehicular en la Megalópolis de la Ciudad de México, se consideran las mejoras competidas de la nueva forma de verificación vehiculas establecidas en la Norma Emergente NOM-EM-167-SEMARNAT-2016, contra los límites máximos de emisiones contaminantes para vehículos que usan gasolina como combustible establecidos en la NOM-041 SEMARNAT 2006, los límites máximos de permisibles de hidrocarburos o no metanos, CO, NOx y particular provenientes de los escapes de vehículos cuyo peso no exceda los 3,857 Kg establecidos en la NOM-042, y en NOM-044 cuando el peso bruto vehicular excede los 3,857 Kg., así como con la NOM-045, que establece los límites máximos y métodos de medición de la opacidad en vehículos que utilizan Diésel como combustible y finalmente con la NOM-047, que establece las características del equipo y procedimiento de medición para la verificación de los límites de emisiones contaminantes de vehículos que usan gasolina, gas LP, Gas Natural y otros combustibles alternos

Proteomics Analysis of Extracellular Matrix Remodeling During Zebrafish Heart Regeneration

Adult zebrafish, in contrast to mammals, are able to regenerate their hearts in response to injury or experimental amputation. Our understanding of the cellular and molecular bases that underlie this process, although fragmentary, has increased significantly over the last years. However, the role of the extracellular matrix (ECM) during zebrafish heart regeneration has been comparatively rarely explored. Here, we set out to characterize the ECM protein composition in adult zebrafish hearts, and whether it changed during the regenerative response. For this purpose, we first established a decellularization protocol of adult zebrafish ventricles that significantly enriched the yield of ECM proteins. We then performed proteomic analyses of decellularized control hearts and at different times of regeneration. Our results show a dynamic change in ECM protein composition, most evident at the earliest (7 days postamputation) time point analyzed. Regeneration associated with sharp increases in specific ECM proteins, and with an overall decrease in collagens and cytoskeletal proteins. We finally tested by atomic force microscopy that the changes in ECM composition translated to decreased ECM stiffness. Our cumulative results identify changes in the protein composition and mechanical properties of the zebrafish heart ECM during regeneration