Determinants of Alanine Dipeptide Conformational Equilibria on Graphene and Hydroxylated Derivatives

Citation: Poblete, H., Miranda-Carvajal, I., & Comer, J. (2017). Determinants of Alanine Dipeptide Conformational Equilibria on Graphene and Hydroxylated Derivatives. The Journal of Physical Chemistry B. https://doi.org/10.1021/acs.jpcb.7b01130Understanding the interaction of carbon nanomaterials with proteins is essential for determining the potential effects of these materials on health and in the design of biotechnology based on them. Here we leverage explicit-solvent molecular simulation and multidimensional free-energy calculations to investigate how adsorption to carbon nanomaterial surfaces affects the conformational equilibrium of alanine dipeptide, a widely used model of protein backbone structure. We find that the two most favorable structures of alanine dipeptide on graphene (or large carbon nanotubes) correspond to the two amide linkages lying in the same plane, flat against the surface, rather than the nonplanar ?-helix-like and ?-sheet-like conformations that predominate in aqueous solution. On graphenic surfaces, the latter conformations are metastable and most often correspond to amide?? stacking of the N-terminal amide. The calculations highlight the key role of amide?? interactions in determining the conformational equilibrium. Lesser but significant contributions from hydrogen bonding to the high density interfacial water layer or to the hydroxy groups of hydroxylated graphene also define the most favorable conformations. This work should yield insight on the influence of carbon nanotubes, graphene, and their functionalized derivatives on protein structure

Pharmacological and Nonpharmacological Therapeutic Strategies Based on the Pathophysiology of Acute and Chronic Spinal Cord Injury

Spinal cord injury (SCI) induces a series of anatomic and physiological disorders which have severe repercussions on neural function. SCI is classified chronologically into an acute (primary and secondary phase) and a chronic phase. The primary phase results directly from the initial trauma and is comprised of disturbances in neural tissue (mainly axons), blood vessels, and spinal shock. Secondary injury results from a series of time-dependent pathophysiological changes, beginning in the first minutes after SCI and lasting days and weeks. This phase is characterized by biochemical and immunological alterations in the injury site and periphery, leading to neuronal over-excitation, apoptosis, and axonal demyelination. In chronic stages, the pathophysiology consists of disturbances in fiber organization, oligodendrocyte apoptosis, fibroglial scar formation, and cyst formation, leading to parenchymal alterations such as syringomyelia and hydromyelia hindering the possibility for functional basal axonal regeneration. This chapter will review a wide range of pharmacological and nonpharmacological therapeutic strategies in preclinical and clinical phases, each targeting different pathological mechanisms of SCI in acute and chronic stages of SCI; taking into account limitations, advances, scope, and new trends. The chapter focuses on the general aspects of SCI pathophysiology, pharmacological and nonpharmacological treatments acute and chronic stages of SCI

Innovations in Educational Research and Teaching of Experimental Calculus

For several decades, there have been a varying number of books on Calculus following the classic line of mathematical thought, where Mathematics is taught for everybody by means of rigorous definitions, theorems, and carefully detailed and extensive demonstrations. For mathematical education into the XXI Century the students need to achieve ability in handling of present mathematical tools and concepts from the beginning of their courses. These needs can be achieved today by means of a paradigmatic change in the focus of mathematics teaching: to learn to develop ideas and to experiment and test those ideas in such way that students can verify their own inferences. In this paper we report an educational research in teaching and learning functions models according to a new paradigm in hands-on experimental mathematics, with applications in the real world, i.e. sciences and engineering by using Computer Algebra Systems. The study of functions is presented, focused into the framing of Exploratory Learning Systems, where students learn by means of the action and their participation in it. It is designed for teachers working together with students in a computer laboratory like hands-on workshops-type activities on other sciences. In this way students have a more “alive”, “realistic” and “accessible” touch in Calculus

Tricuspid valve intervention at the time of pulmonary valve replacement in adults with congenital heart disease: A systematic review and meta-analysis

Background Tricuspid regurgitation (TR) is a common finding in adults with congenital heart disease referred for pulmonary valve replacement (PVR). However, indications for combined valve surgery remain controversial. This study aimed to evaluate early results of concomitant tricuspid valve intervention (TVI) at the time of PVR. Methods and Results Observational studies comparing TVI+PVR and isolated PVR were identified by a systematic search of published research. Random-effects meta-analysis was performed, comparing outcomes between the 2 groups. Six studies involving 749 patients (TVI+PVR, 278 patients; PVR, 471 patients) met the eligibility criteria. In the pooled analysis, both TVI+PVR and PVR reduced TR grade, pulmonary regurgitation grade, right ventricular end-diastolic volume, and right ventricular end-systolic volumes. TVI+PVR, but not PVR, was associated with a decrease in tricuspid valve annulus size (mean difference, -6.43 mm, 95% CI, -10.59 to -2.27

A new serotype 14 variant of the pneumococcal Spain9V-3 international clone detected in the central region of Argentina

The penicillin-resistant Spain9V-3 clone of Streptococcus pneumoniae is widespread and presents different serotype variants originating from recombination of the capsular genes. In this work, the genetic relatedness of 29 invasive pneumococci isolated from the central region of Argentina (Cordoba, Buenos Aires, Santa Fe and La Pampa provinces) was assessed by multilocus sequence typing (MLST). All of the penicillin-non-susceptible isolates studied (21/29) belonged to a serotype 14 variant of the Spain 9V-3 clone. This clone was predominant, suggesting that it was responsible for the penicillin resistance spread in this region. Interestingly, this serotype 14 variant (named Cordoba S14V) could be differentiated from the European one by its pbp1a gene, suggesting a different recombinational replacement of the capsular genes. The putative recombination sites were analysed, resulting in the proximal crossover point being clearly localized in the spr0309 gene, with the distal site restricted to the recU gene, confirming a different recombination event. Analysis of the dexB, cpsB, aliA and pbp1a genes from these strains showed a high similarity with the corresponding genes of the Spain14-5 clone, suggesting that the capsular genes were provided by this international clone. Analysis of the genetic polymorphisms of the pbp1a (nt 1473-1922) and spr0309 (nt 1-790) genes is proposed as an epidemiological tool to help recognize the Cordoba S14V of the Spain9V-3 clone. On the other hand, BOX-repeat-based PCR and MLST analyses of serotype 14 strains revealed a divergent epidemiology of the Cordoba S14V, suggesting a non-recent dissemination in the paediatric population. It is suggested that this molecular epidemiology work will be a reference for monitoring the evolution of S14Vs of Spain9V-3, the emergence of new clones and the impact of pneumococcal vaccination programmes in Argentina.Fil: Albarracín Orio, Andrea Georgina. Universidad Católica de Córdoba. Instituto de Investigaciones en Recursos Naturales y Sustentabilidad José Sanchez Labrador S. J. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Recursos Naturales y Sustentabilidad José Sanchez Labrador S. J.; ArgentinaFil: Cortes, Paulo. Hospital Pediátrico del Niño Jesús; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Tregnaghi, Miguel. Centro de Desarrollo de Proyectos Avanzados en Pediatria; ArgentinaFil: Piñas, German Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Echenique, Jose Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Yudowski, Silvia. Centro de Desarrollo de Proyectos Avanzados en Pediatria; ArgentinaFil: Carvajal, Lydia. Centro de Desarrollo de Proyectos Avanzados en Pediatria; ArgentinaFil: Culasso, Catalina. Centro de Desarrollo de Proyectos Avanzados en Pediatria; ArgentinaFil: Nobile, Carmen Beatriz. Centro de Desarrollo de Proyectos Avanzados en Pediatria; ArgentinaFil: Figueroa, Myriam Haydee. Centro de Desarrollo de Proyectos Avanzados en Pediatria; ArgentinaFil: Lopardo, Horacio. Fundacion Hospital de Pediatria Professor Dr. Juan P. Garrahan; ArgentinaFil: Hernández, Claudia. Fundacion Hospital de Pediatria Professor Dr. Juan P. Garrahan; ArgentinaFil: Regueira, Mabel. Instituto Nacional de Enfermedades Infecciosas; Argentin

COMPARISON OF THE LEVELS OF DENTAL FLUOROSIS IN STUDENTS OF TWO MUNICIPALITIES FROM SANTANDER

Objective: To compare the levels of dental fluorosis in students between the 6 and 17 years old in two scholar institutions from two municipalities of Santander.Material and methods: An observational descriptive cross sectional study was done; the universe and the sample were integrated by the totality of scholars of two educational institutions for two municipalities of Santander. Sociodemographic variables, systemic conditions, perception of the teeth appearance, dental decay (COP index) and dental flurosis (Dean and Thysltrup & Fejerskov index) were registered. The statistic analysis implied the calculation of summary measures according to the nature of the variables; by bivariate analysis the municipality was considered like exit variable, for the qualitative variables Chi square and Fisher Exact test was applied and by the quantitative variables t student and Wilcoxon ranks test was used.Results: Three hundred forty and two students were evaluated, 249 subjects came from Oiba and 93 from Cepita. In Oiba, 80.7% subjects and 97.8% from Cepita registered dental fluorosis.Conclusions: Although the prevalence of fluorosis observed in Cepita were superior, the results must be look with discretion based on the differences of age between the two populations.Objetivo: Describir los niveles de fluorosis dental en escolares entre los 6 y 17 años de edad vinculados a dos instituciones educativas de dos municipios de Santander.Materiales y métodos: Se realizó un estudio observacional descriptivo de corte transversal; el universo y la muestra estuvo integrada por la totalidad de escolares vinculados a dos concentraciones educativas de dos municipios de Santander. Se recolectaron variables sociodemográficas, condiciones sistémicas, percepción de los menores frente a la apariencia de sus dientes, caries dental (índice COP) y la fluorosis dental (índice de Dean e índice de Thysltrup & Fejerskov). El análisis estadístico implicó el cálculo de medidas de resumen según la naturaleza de las variables; para el bivariado se consideró como variable de salida, municipio de residencia y las otras como explicatorias, para las variables cualitativas se aplicó test de Chi2 y Exacto de Fisher y para las cuantitativas prueba t de Student o test de rangos de Wilcoxon.Resultados: Se evaluaron 342 escolares, 249 sujetos procedían de Oiba y 93 de Cepitá. El 80.7% de las personas del primer municipio y el 97.8% del segundo registraron fluorosis dental.Conclusión: Aunque la prevalencia de fluorosis observada en el municipio de Cepitá fue superior a la de Oiba, los resultados deben mirarse con discreción debido a las diferencias de edad entre las poblaciones.[Blanco H, Durán L, Neira LN, Pourgoshtasbi L, Carvajal LC, Concha SC. Comparación de los niveles de fluorosis dental en escolares de dos municipios de Santander. Ustasalud 2008; 7: 108 - 116

Modelos teóricos para fisioterapia

PublishedEl presente libro proviene de la motivación del Programa de Fisioterapia de la Universidad Santiago de Cali en contribuir a la comunidad académica y profesional con un texto que compile los principales paradigmas teóricos que aportan al desarrollo disciplinar, y que han permitido abordar diversas problemáticas de investigación y de la práctica en diferentes contextos de desempeño del fisioterapeuta en el entramado de lo clínico y social. La compilación de teorías y modelos en los tradicionales campos de acción, traducen en gran medida la complejidad de los saberes en torno al movimiento corporal humano como objeto de estudio de la fisioterapia, y constituye un ejercicio académico donde cada autor desde su experiencia y formación reconoce este objeto como un resultado de elementos físicos, psicológicos y sociales que impactan el bienestar y la salud del hombre

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Cristalización desde soluciones

El presente trabajo se ha desarrollado en dos secciones, cada una con objetivos propios y diferenciados. En la primera parte se muestran los principios básicos de la cristalización desde soluciones y está orientada a la interpretación y correlación de datos experimentales sobre la cinética del proceso y su posible aplicación a problemas industriales.La segunda parte estádedicada a analizar un método experimental para determinar cinéticas de cristalización. El procedimiento propuesto, sencillo y de bajo costo, permite estudiar el efecto de las variables más importantes, tales como grado de sobresaturación, tiempo de residencia, temperatura, velocidad de agitación, etc., en un proceso de cristalización realizado en un equipo tipo continuo, agitado

Diseño preliminar de un cristalizador de suspensión mezclada con remoción de producto mezclado (SMRPM)

Se describe un método para el diseño preliminar de un cristalizador del tipo SMRPM, operando por evaporación o enfriamiento para el sistema KNO3-H20, basándose en la información experimental de la cinética de nucleación y crecimiento de cristales que aparecen en la literatura, así como en las propiedades físicas del sistema cristalizante. Por resolución conjunta de los balances de masa y población se puede obtener el volumen del cristalizador como función de la temperatura de operación. Se utilizó como criterio de optimización minimizar el volumen del equipo, a una temperatura comprendida en un intervalo que permita hacer mínima la formación de incrustaciones en los intercambiadores de calor. Los resultados obtenidos concuerdan con los valores de capacidad y tiempo de residencia correspondientes a equipos industriales en uso. Sin embargo, es imprescindible hacer pruebas a nivel de planta piloto para lograr un buen escalamiento en el diseño del equipo