Chitosan, Chitosan Derivatives and their Biomedical Applications

Chitosan is one of the most studied polysaccharides nowadays. Because of its biocompatibility, biodegradability and abundance in nature, it has had a wide number of applications. In this chapter, an overview of chitosan including its physicochemical properties and characterization methods is presented. Subsequently, the main chitosan chemical modifications via the hydroxyl and amino groups are discussed. These chemical modifications improve chitosan physical properties and expand its range of applications especially in the biomedical field which will also be studied

Influencia de la incorporación de un co-monómero alcalino e hidroxiapatita en las propiedades de cementos óseos acrílicos

Se formularon cementos óseos acrílicos utilizando una relación sólido / líquido de 2. El componente líquido se basó en metacrilato de metilo (MMA), como monómero y dimetil-p-toluidina (2.5%) como acelerador; a su vez, el componente sólido consistió en perlas de polimetacrilato de metilo (PMMA) como carga, sulfato de bario como agente radiopaco y peróxido de benzoilo (2%) como iniciador. Finalmente, una hidroxiapatita como carga bioactiva y un metacrilato de dimetil amino etilo (DMAEM) como co-monómero alcalino, fueron incorporados en diferentes porcentajes (0-20% p/p, para el primero y 0-10% p/p, para el segundo). Como era de esperarse, las muestras elaboradas con las formulaciones de cementos óseos acrílicos sin modificar, presentaron calores de reacción elevados ( and gt;80ºC) y una resistencia a la compresión (124.0 MPa) por encima de lo especificado en la norma ISO 5833. Con la incorporación de la hidroxiapatita y el co-monómero alcalino, se presentaron bajas temperaturas de polimerización, bajos módulos y resistencias mecánicas, así como la fijación de una capa similar a la apatita biológica en la superficie del material después de su inmersión por 30 días en un fluido biológico simulado

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

La Influencia De La Recreacion En El Aumento De La Produccion Y El Mejoramiento De La Calidad De Vida De Los Empleados De La Fabrica Muebles Del Quindio

Leaving or the preleaving of the premise that the recreation allows to improve the quality of the individuals’ life since it contributes in the development psicosocial of who practice it, of investigating the influence that can have the recreational programs into the organizations for it we account with of the directives of it of the fábrica Muebles del Quindio of the Armenia city they considered interesting the possibility to create mechanisms that allowed them to improve the yield of workers give them the possibility to be developed integrally. The biggest obstacle that was presented in the development of the investigation was the lack of convincing on the part of the workers, about the benefits that one every can obtain through the recreation practiced during the labor day, however, as they done diverse activities, it was possible to capture your attention, getting this way that all the workers participated and they collaborate in the investigative work. Also on the part of the directive of it factory we got the recognition of the importance of the recreational programs that allow the humanization of the work and the productive efficiency.A lo largo y ancho de Sur América y del mundo, la recreación se torna más importante día a día, dicha exigencia originada por el aumento del tiempo libre, por el incremento poblacional, por la urbanización, por el marcado índice de estrés y la tendencia a la industrialización y la tecnología, esto ha determinado que a los líderes recreativos, se les demande acciones de mayor responsabilidad y de alta calidad con el manejo de sus programas. Partiendo de la premisa de que la recreación permite mejorar la calidad de vida de los individuos, ya que contribuye en el desarrollo psicosocial de quienes la practican, se trató de investigar la influencia que pueden tener los programas recreativos al interior de las organizaciones empresariales. Para ello se contó con la colaboración de los directivos de la Fábrica Muebles del Quindio de la ciudad de Armenia, quienes consideraron interesante la posibilidad de crear mecanismos que les permitieran mejorar el rendimiento de sus trabajadores, brindándoles la posibilidad de desarrollarse integralmente. El mayor obstáculo que se presentó en el desarrollo de la investigación fue la falta de convencimiento por parte de los trabajadores acerca de los beneficios que se pueden obtener a través de la recreación practicada durante la jornada laboral, sin embargo, a medida que se fueron realizando diversas actividades, se logró captar su atención, consiguiendo así que todos los trabajadores participaran y colaboraran en el trabajo investigativo. Además por parte de los directivos de la fábrica, se alcanzó el reconocimiento de la importancia de los programas recreativos que permiten la humanización del trabajo y la eficiencia productiva.1. Introducción 12. Marco General De La Investigación 93. Diseño Metodologico 22PregradoLicenciado en Educación Física y Deporte

Desarrollo de una matriz polimérica obtenida por la técnica de electrospinning para regeneración ósea.

Los accidentes de tránsito en Colombia presentan una gran prevalencia y las estadísticas del instituto colombiano de Medicina Legal muestran una tendencia a conservarse así. Una de las zonas anatómicas más afectadas en un accidente de tránsito es el complejo cráneo facial. Los huesos del cráneo y de la cara a menudo presentan problemas para regenerarse, siendo necesario recurrir a técnicas reconstructivas y en el caso del cráneo, a elementos como las mallas y láminas de titanio que aunque logran sellar la cavidad, son incapaces de estimular la regeneración ósea y elevan notablemente los costos del tratamiento. Los defectos óseos de gran tamaño se comportan como “críticos”, y son incapaces de cicatrizar espontáneamente, siendo necesario la utilización de injertos o sustitutos óseos para estimular la iniciación y desarrollo del proceso regenerativo. También son considerados defectos de tamaño crítico las cavidades que permanecen como consecuencia de la extirpación quirúrgica de lesiones intraóseas como tumores, quistes, osteomielitis, etc., y las pérdidas fisiológicas de los rebordes alveolares en la cavidad oral. Los materiales de elección para injerto, son en primer lugar el hueso del propio paciente (autoinjerto), y como segunda opción los aloinjertos, provenientes de un banco de hueso, o los xenoinjertos, que tienen su origen en otras especies. El desarrollo científico, con la aparición de la Ingeniería de Tejidos, ha permitido una tercera opción que son los aloplásticos, materiales sintéticos capaces de servir como soporte al desarrollo tisular. De la gran variedad de materiales utilizados, los polímeros por sus propiedades físicas, químicas y biológicas, son los mejores candidatos para la elaboración de matrices, con las cuales se busca estimular el proceso regenerativo y reparar el tejido dañado mediante la incorporación de células del mismo organismo

Desarrollo de materiales mesoporosos basados en compuestos hidrazónicos y fullerénicos para aplicaciones fotovoltaícas.

Se obtuvieron nuevos derivados de fullereno (fulleropirazolina y fulleropirrolidina) mediante la reacción de cicloadición [3+2] entre C60 e hidrazonas derivadas de piridinas. Los compuestos obtenidos durante la ruta sintética fueron caracterizados por espectroscopía de resonancia magnética nuclear (RMN), UV-Visible, FT-IR y algunos de ellos por difracción de rayos X. El comportamiento electroquímico de ambos derivados fue investigado, encontrándose que la fulleropirazolina muestra desplazamientos anódicos en los potenciales de reducción comparados con aquellos del fullereno, mientras que la fulleropirrolina exhibe corrimientos catódicos. Adicionalmente, se sintetizaron complejos de coordinación a partir de la fulleropirrolidina y cationes metálicos, tales como Zn+2, Cd+2 y Fe+2. Mediante los métodos de Jobs y Benessi-Hildebrand se comprobó que dichos complejos poseen una relación estequiométrica 1:1 metal-ligando con constantes de acoplamiento comprendidas entre 1.59 y 2.26 x105 M-1, donde la afinidad de estos ligandos con el metal se encuentra directamente relacionada con el radio iónico (Fe+2 < Zn+2 < Cd+2) favoreciendo así, a los más grandes. Finalmente, la electroquímica de estos complejos mostró una marcada influencia del ion metálico sobre los potenciales de reducción, lo que permite inferir que dichos potenciales pueden ser desplazados anódica o catódicamente al variar la porción hexahedral en los derivados de fullereno. La preparación de materiales mesoporosos está supeditada a la preparación de moléculas simétricas y a la coordinación 2:1 (ligando: metal), en nuestro caso particular, ninguno de los complejos fullerénicos exhibió coordinación 2:1, por lo tanto, es necesario investigar aún más sobre cuáles metales y/o estructuras coordinantes puedan servir para la obtención de estructuras mesoporosas

Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p &lt; 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures

Impact of COVID-19 on Diagnostic Cardiac Procedural Volume in Oceania: The IAEA Non-Invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Objectives: The INCAPS COVID Oceania study aimed to assess the impact caused by the COVID-19 pandemic on cardiac procedure volume provided in the Oceania region. Methods: A retrospective survey was performed comparing procedure volumes within March 2019 (pre-COVID-19) with April 2020 (during first wave of COVID-19 pandemic). Sixty-three (63) health care facilities within Oceania that perform cardiac diagnostic procedures were surveyed, including a mixture of metropolitan and regional, hospital and outpatient, public and private sites, and 846 facilities outside of Oceania. The percentage change in procedure volume was measured between March 2019 and April 2020, compared by test type and by facility. Results: In Oceania, the total cardiac diagnostic procedure volume was reduced by 52.2% from March 2019 to April 2020, compared to a reduction of 75.9% seen in the rest of the world (p&lt;0.001). Within Oceania sites, this reduction varied significantly between procedure types, but not between types of health care facility. All procedure types (other than stress cardiac magnetic resonance [CMR] and positron emission tomography [PET]) saw significant reductions in volume over this time period (p&lt;0.001). In Oceania, transthoracic echocardiography (TTE) decreased by 51.6%, transoesophageal echocardiography (TOE) by 74.0%, and stress tests by 65% overall, which was more pronounced for stress electrocardiograph (ECG) (81.8%) and stress echocardiography (76.7%) compared to stress single-photon emission computerised tomography (SPECT) (44.3%). Invasive coronary angiography decreased by 36.7% in Oceania. Conclusion: A significant reduction in cardiac diagnostic procedure volume was seen across all facility types in Oceania and was likely a function of recommendations from cardiac societies and directives from government to minimise spread of COVID-19 amongst patients and staff. Longer term evaluation is important to assess for negative patient outcomes which may relate to deferral of usual models of care within cardiology

International Impact of COVID-19 on the Diagnosis of Heart Disease

Background: The coronavirus disease 2019 (COVID-19) pandemic has adversely affected diagnosis and treatment of noncommunicable diseases. Its effects on delivery of diagnostic care for cardiovascular disease, which remains the leading cause of death worldwide, have not been quantified. Objectives: The study sought to assess COVID-19's impact on global cardiovascular diagnostic procedural volumes and safety practices. Methods: The International Atomic Energy Agency conducted a worldwide survey assessing alterations in cardiovascular procedure volumes and safety practices resulting from COVID-19. Noninvasive and invasive cardiac testing volumes were obtained from participating sites for March and April 2020 and compared with those from March 2019. Availability of personal protective equipment and pandemic-related testing practice changes were ascertained. Results: Surveys were submitted from 909 inpatient and outpatient centers performing cardiac diagnostic procedures, in 108 countries. Procedure volumes decreased 42% from March 2019 to March 2020, and 64% from March 2019 to April 2020. Transthoracic echocardiography decreased by 59%, transesophageal echocardiography 76%, and stress tests 78%, which varied between stress modalities. Coronary angiography (invasive or computed tomography) decreased 55% (p &lt; 0.001 for each procedure). In multivariable regression, significantly greater reduction in procedures occurred for centers in countries with lower gross domestic product. Location in a low-income and lower–middle-income country was associated with an additional 22% reduction in cardiac procedures and less availability of personal protective equipment and telehealth. Conclusions: COVID-19 was associated with a significant and abrupt reduction in cardiovascular diagnostic testing across the globe, especially affecting the world's economically challenged. Further study of cardiovascular outcomes and COVID-19–related changes in care delivery is warranted