Optimization of the Synthesis Procedures of Graphene and Graphite Oxide

The optimization of both the chemical vapor deposition (CVD) synthesis method to prepare graphene and the Improved Hummers method to prepare graphite oxide is reported. Copper and nickel were used as catalysts in the CVD-graphene synthesis, CH4 and H2being used as precursor gases. Synthesis variables were optimized according to a thickness value, calculated using a homemade Excel-VBA application. In the case of copper, the maximum thickness value was obtained for those samples synthesized at 1050°C, a CH4/H2 flow rate ratio of 0.07 v/v, a total flow of 60 Nml/min, and a time on stream of 10 min. In the case of nickel, a reaction temperature of 980°C, a CH4/H2 flow rate ratio of 0.07 v/v, a total flow of 80 Nml/min, and a time on stream of 1 min were required to obtain a high thickness value. On the other hand, the Improved Hummers method used in the synthesis of graphite oxide was optimized. The resultant product was similar to that reported in literature in terms of quality and characteristics but both time and cost of the synthesis procedure were considerably decreased

Atrofiamiento del vello utilizando la técnica de depilación IPL, un enfoque estético.

Este documento se constituye en un artículo de revisión versado sobre la técnica IPL (intense pulsed light o luz intensa pulsada) utilizada en la atrofia del vello, en cuanto se refiere al uso estético de esta técnica.La revisión bibliográfica llevada a cabo permitió organizar el documento de la siguiente manera: definición de vello, descripción del proceso de atrofiamiento del vello, descripción y justificación del proceso de depilación, clasificación de los fototipos cutáneos, definición de la técnica de depilación IPL, atrofiamiento del vello mediante el uso de la técnica IPL, posibles reacciones adversas derivadas de la aplicación de la técnica IPL, principales indicaciones para el uso de la metodología de depilación IPL y contraindicaciones en el uso de la metodología de depilación IPL.El objetivo del trabajo se basa en identificar a nivel estético, las ventajas, desventajas y contraindicaciones del uso de la técnica de depilación IPL.A partir de la estructuración del trabajo se concluye que para llevar a cabo un proceso de depilación IPL se debe llevar a cabo un previa valoración médica del usuario, procedimiento en el cual se debe establecer el fototipo cutáneo según la escala de Fitzpatrick, debido a que este tipo de depilación es solo aconsejable para los fototipos I a III

Anti-carbamylated protein and peptide antibodies as potential inflammatory joint biomarkers in the relatives of rheumatoid arthritis patients

*Q3Objective: Antibodies against carbamylated proteins/peptide (CarP) have been associated with severity in rheumatoid arthritis (RA) patients. However, their role in risk groups, specific targets and relation with periodontal disease (PD) is uncertain yet. The aim of this study was evaluated the association between the levels of anti- CarP with clinical manifestation, human leukocyte antigen (HLA) alleles, periodontal activity markers, PD diagnosis, PD severity, and presence of Porphyromonas gingivalis (P gingivalis) in relatives of patients with RA. Methods: One hundred and twenty-four individuals with a family history of RA in first-degree relatives (FDR) and 124 healthy individuals gender- and age-matched, RA activity was assessed. Antibodies against carbamylated protein anti-FCS-Carp and 2 carbamylated peptides of fibrinogen were selected (anti-Ca-Fib2, anti-Ca-Fib3). Results: Anti-FCS-Carp-positive, anti-Ca-Fib2 and anti-Ca-Fib3 were more frequent in FDR than controls (25.0% vs 14.5%, 34.7% vs 15.3% and 33.1% vs 11.3%, respectively). Anti-FCS-CarP were associated with the HLA-DRB1-SE* 1402 allele (P = .035) and highly sensitive C-reactive protein levels (P = .016), the anti-Ca-Fib2 antibodies were associated with the HLA-DRB1-SE* 1501 allele (P = .03), with non-SE* 0901 allele (P = .01), the anti-Ca-Fib3 was associated with positive rheumatoid factor (P = .0012). The FDR condition was associated with the presence of anti-Ca-Fib3 (odds ratio [OR] =4.7; 95% CI = 1.8-11.7; P = .001) and painful joints (OR = 2.2; 95% CI = 1.01-4.68; P = .045); we also detected an important trend toward the presence of P gingivalis (OR = 1.9; 95% CI = 0.9-3.7; P = .062). Conclusion: The presence of anti-FCS-Carp, anti-Ca-Fib3 and anti-Ca-Fib2 antibodies may have a role for these antibodies as early biomarkers in the development of RA, probably including additional mechanisms related with other non-SE alleles; the anti-peptide antibodies proposed in the present study may represent a simpler way to identify antibodies directed to a specific target.N/

Causas de la explotación laboral infantil y el aporte del profesional en Trabajo Social, en el municipio de San Vicente, departamento de San Vicente.

La investigación denominada “Causas de la explotación laboral infantil y el aporte del profesional en Trabajo Social, en el municipio de San Vicente, departamento de San Vicente”, está dirigida al estudio de niños y niñas laborando verificando si gozan de los derechos que les corresponden. El objetivo de la investigación es conocer las causas, riesgos y el accionar de los actores locales, asimismo se pueda disminuir los índices de trabajo infantil a través de una propuesta de proyecto. Para la obtención de la información se aplica el método inductivo de investigación con técnicas cualitativas: observación y entrevista; y sus instrumentos: guía de observación y ficha de entrevista. El proceso de la investigación fue teórico y práctico, ya que la información que existía sobre esta problemática social indica la transcendencia que ha tenido durante años, no siendo un problema reciente y que el cual ha ido aumentando en todo el mundo. La investigación de campo refleja la realidad que vive cada uno de estos niños y niñas realizando diferentes actividades de subsistencia, permitiendo conocer el accionar de las diferentes instituciones que están relacionadas por el bienestar de la niñez, al momento de realizar las entrevistas. De igual manera se conocen los riesgos a los que estos niños y niñas se exponen al momento de laborar, en su mayoría físicos y psicológicos, además de la inseguridad e insalubridad de los lugares donde trabajan. En algunos casos, afectando en la parte educativaya que la asistencia a clases depende de los ingresos económicos que generen, así también su alimentación no es adecuada ya que carecen de los nutrientes que requieren acorde a sus edades para llevar un buen desarrollo físico. The research was entitled "Causes of child labor exploitation and the contribution of professional work, in the municipality of San Vicente, in the department of San Vicente", is directed to the study of children working verifying and enjoying the rights that they corresponds. The objective of the research is to know the causes, risks and actions of local actors, aswell as to reduce child labor rates through a project proposal. To obtain the information, the inductive research method is applied with qualitative techniques: observation and interview; and its instruments: observation guide and interview record. The process of the investigation was theoretical and practical, since the information that existed on this social problem indicates the transcendence that it has had for years, not being a recent problem and which has been increasing all over the world. The field research reflects the reality that each one of these children lives performing different subsistence activities, allowing knowing the actions of the different institutions that are related to the welfare of the children, at the time of conducting the interviews. In the same way, the risks to which these children are exposed at work, mostly physical and psychological, as well as the insecurity and unhealthiness of the places where they work, are known. In some cases, affecting the educational part as the assistance to classes depends on the economic income they generate, so their diet is not adequate because they lack the nutrients they require according to their ages to lead a good physical development

Graphene-based materials behaviour for dyes adsorption

Due to the environmental damage caused by dye dumping, the scientific community has been researching into different adsorbents in order to mitigate this impact. In this respect, different graphene-based materials with a high adsorption capacity were studied (graphite and graphene oxide and two different types of reduced graphene oxide). In this work, four graphene-based materials with different properties and structures were evaluated. All materials were those obtained at each step in the pathway of oxidation, exfoliation, and reduction of graphite for conversion into reduced graphene. These four materials were characterized in depth by different methods (RAMAN, XRD, EDX, SEM, FTIR). Adsorption variables were researched to demonstrate their great adsorptive rate, which reached in some cases values of over 300 mg/g of adsorbed dye. Therefore, this study established a relationship between the physicochemical properties of the materials and their adsorption capacity. Furthermore, the effect of different variables on the process was studied: temperature, contact time and amount of adsorbent.This study creates new adsorbent materials with a long lifespan, reducing the environmental impact of industry on nature.Debido al daño ambiental causado por el vertido de colorantes, la comunidad científica ha estado investigando diferentes adsorbentes para mitigar este impacto. En este sentido, se estudiaron diferentes materiales a base de grafeno con una alta capacidad de adsorción (grafito y óxido de grafenoy dos tipos diferentes de óxido de grafeno reducido). En este trabajo se evaluaron cuatro materiales a base de grafeno con diferentes propiedades y estructuras. Todos los materiales fueron los obtenidos en cada paso del proceso de oxidación, exfoliación y reducción del grafito para convertirlo en grafeno reducido. Estos cuatro materiales se caracterizaron en profundidad por diferentes métodos (RAMAN, XRD, EDX, SEM, FTIR). Se investigaron variables de adsorción para demostrar su gran tasa de adsorción, que alcanzó en algunos casos valores superiores a 300 mg/g de colorante adsorbido. Por lo tanto, este estudio estableció una relación entre las propiedades fisicoquímicas de los materiales y su capacidad de adsorción. Además, se estudió el efecto de diferentes variables en el proceso: temperatura, tiempo de contacto y cantidad de adsorbente

Experiencia de aula virtual: el maltrato animal desde la educación matemática crítica

In this article we present our total immersion practice experience, carried out as seventhsemester students of the Mathematics Degree at the National Pedagogical University. We describe the design and implementation process of three virtual learning scenarios during the Covid-19 health emergency. These focused on the social problem of animal abuse in Bogotá, from the perspective of Critical Mathematics Education. The learning objective that we proposed for the development of the scenarios was to understand the problem, through the mathematical object of ratio, proportion and proportionality (RPP), using statistics from the Institute of Animal Welfare andProtection (idpyba, 2020) and the Administrative Department National Statistics (Dane, 2020), to later analyze whether the statistical data obtained were relevant to the situation studied. Finally, we reflect on the difficulties identified in the classroom, related to the context and the mathematical object used in this process and based on the above, we ask ourselves the following question: Is it possible to design a teaching proposal with an approach that is not expository and that guarantees that the studentbuilds the concepts of reason, proportion and proportionality (RPP) taking into account the socio-cultural context of the students?En este artículo se describe una experiencia de práctica de inmersión total realizada durante el séptimo semestre de la Licenciaturaen Matemáticas de la Universidad Pedagógica Nacional. Se explica el proceso de diseño e implementación de tres escenarios de aprendizaje virtuales durante la emergencia sanitaria del covid-19, los cuales se enfocaron en la problemática social del maltrato animal en Bogotá desde la perspectiva de la educación matemática crítica. El objetivo de aprendizaje de los escenariosfue comprender la problemática a través del objeto matemático de razón, proporción y proporcionalidad (RPP). Para ello, se utilizaronestadísticas del Instituto de Bienestar y Protección Animal (idpyba, 2020) y del Departamento Administrativo Nacional de Estadística (Dane, 2020). Posteriormente, se analizaron los datos estadísticos obtenidos para determinar su pertinencia con la situación estudiada. Finalmente, se reflexionó acerca de las dificultades identificadas en el aula, relacionadas con el contexto y el objeto matemático utilizado en este proceso. Con base en lo anterior, se planteó la siguiente pregunta: ¿Es posible diseñar una propuesta de enseñanza con un enfoque que no sea expositivo y que garantice que el estudiante construya los conceptos de razón, proporción y proporcionalidad (RPP) teniendo en cuenta el contexto sociocultural de los estudiantes

APLICACIÓN MOVIL PARA EL ANÁLISIS, RECONOCIMIENTO Y RECUPERACIÓN DE INFORMACIÓN DE OBRAS DE ARTE DE UN MUSEO (MOBILE APP FOR ANALYSIS, RECOGNITION, AND RETRIEVAL OF INFORMATION OF MUSEUM ARTWORKS)

Resumen Al visitar un museo, la información completa sobre una obra de arte puede requerirse; sin embargo, a un lado de la misma sólo se encuentran su nombre y del artista. Por tanto, en este trabajo se presenta el análisis y reconocimiento una obra de arte mediante la fotografía tomada con el celular del visitante, así como la recuperación de los datos más relevantes de la misma. De tal manera, que se obtenga la información completa en ese momento. Esta propuesta resulta importante para cualquier persona interesada en la cultura o que simplemente sienta curiosidad por una obra de arte. Consecuentemente, la aplicación resultante se puede ofrecer como un servicio en la nube a todas estas personas, con un tiempo de respuesta mínimo. Además, en la literatura revisada no se encontró una aplicación que brinde este servicio, tal y como, se especifica en este artículo. Palabras Clave: Análisis de información, obras de arte, museo, reconocimiento de información, recuperación de información. Abstract When visiting a museum, you may want complete information about an artwork. However, to one side of it, only its name and artist are found. Therefore, in this work, the photograph analysis and recognition of an artwork taken with the visitor's cell phone, as well as, the retrieving the most relevant data from it; are presented. In such a way, that it obtains the complete information at that moment. This proposal is important for anyone interested in culture, or simply curious about an art work. Consequently, the resulting application can be offered as a cloud service to all of these people, with minimal response time. Furthermore, in the literature reviewed, an application that provides this service as specified in this article, was not found. Keywords: Artworks, information analysis, information recognition, information retrieval, museum

Development of organic aerogels reinforced with carbonaceous nanomaterials

Aerogels are currently claimed as one of the most promising materials for different applications such as aerospace, high temperature insulation, cryogenic applications, refrigeration systems, outdoor clothing and building insulation [1]. Aerogel [2,3] is a synthetic porous ultralight material derived from a gel, in which the liquid component of the gel has been replaced with a gas. Basically, an organic polymer aerogel is an aerogel with a framework primarily comprised of organic polymers. They are generally less crumbly and brittle than inorganic aerogels. The most common method to obtain wet gels is sol gel process [4,5]. Nevertheless, the resulting products have some disadvantages such as low porosity, low flexibility and low lightness. However, the freeze-drying method, in which the pore liquid is frozen and then sublimed in vacuum, allows the production of porous aerogels with interesting insulating behavior [6]. This method is simple, low-cost and environmentally friendly. Up to date, few works have been reported about the freeze-drying process to produce organic aerogels [7-9]. Carbonaceous nanomaterials are widely employed as reinforcements to form carbon-reinforced composites which have exhibited enhanced mechanical, electrical and functional properties compared to monolithic materials [10]. Carbon nanofibers or nanotubes (CNF, CNT), carbon nanospheres (CNS), reduced graphene oxide (RG) and, graphene oxide (GO) exhibit outstanding physical and mechanical properties, including high surface to volume area, high Young´s modulus, low coefficient of thermal expansion and an entangled structure. Therefore, the mechanical properties and the thermal and the electrical conductivity of the organic aerogels could be enhanced with the addition of these nanomaterials

Linear and crosslinked polyimide aerogels: synthesis and characterization

Linear and crosslinked polyimide aerogels have been synthesized by means of a simple and eco-friendly process. Water-soluble poly(amic acid), PAA, solution was produced and thermal imidization was employed. Furthermore, freeze drying was used. In the present work, the influence of the solid content of the PAA solution and the crosslinking addition on the properties of the resulted aerogels were evaluated. An increase in solid content resulted in denser structures. Thermogravimetric analysis demonstrated thermal stability of polyimide aerogels up to 550 °C. Moreover, the crosslinking addition resulted in mechanical properties improvements. In addition, the obtained polyimide aerogels retained an oil amount of 14 times higher than its dry weight. Besides, polyimide aerogels showed very good values of sound absorption coefficient (maximum value of 0.91) and low thermal conductivities (0.038–0.045 W/m K). Summarizing, PI aerogels presented very good thermal and acoustic insulation properties, excellent thermal stability and good oil sorption capability.Se han sintetizado aerogeles de poliimida lineales y reticulados mediante un proceso sencillo y ecológico. Se produjo una solución de poli(ácido ámico), PAA, soluble en agua y se empleó la imidización térmica. Además, se utilizó liofilización. En el presente trabajo se evaluó la influencia del contenido de sólidos de la solución de PAA y la adición de entrecruzamiento sobre las propiedades de los aerogeles resultantes. Un aumento en el contenido de sólidos resultó en estructuras más densas. El análisis termogravimétrico demostró la estabilidad térmica de los aerogeles de poliimida hasta 550 ºC Además, la adición de reticulación dio como resultado mejoras en las propiedades mecánicas. Además, los aerogeles de poliimida obtenidos retuvieron una cantidad de aceite 14 veces superior a su peso seco. Además, los aerogeles de poliimida mostraron muy buenos valores de coeficiente de absorción acústica (valor máximo de 0,91) y bajas conductividades térmicas (0,038–0,045 W/m · K). En resumen, los aerogeles de PI presentaron muy buenas propiedades de aislamiento térmico y acústico, excelente estabilidad térmica y buena capacidad de sorción de aceite