Site Specifc Growth of Metal Catalyzed Silica Nanowires for Biological and Chemical Sensing

In this research the integration of nanostructures and micro-scale devices was investigated using silica nanowires to develop a simple yet robust nanomanufacturing technique for improving the detection parameters of chemical and biological sensors. This has been achieved with the use of a dielectric barrier layer, to restrict nanowire growth to site-specific locations which has removed the need for post growth processing, by making it possible to place nanostructures on pre-pattern substrates. Nanowires were synthesized using the Vapor-Liquid-Solid growth method. Process parameters (temperature and time) and manufacturing aspects (structural integrity and biocompatibility) were investigated. Silica nanowires were observed experimentally to determine how their physical and chemical properties could be tuned for integration into existing sensing structures. Growth kinetic experiments performed using gold and palladium catalysts at 1050 ˚C for 60 minutes in an open-tube furnace yielded dense and consistent silica nanowire growth. This consistent growth led to the development of growth model fitting, through use of the Maximum Likelihood Estimation (MLE) and Bayesian hierarchical modeling. Transmission electron microscopy studies revealed the nanowires to be amorphous and X-ray diffraction confirmed the composition to be SiO2 . Silica nanowires were monitored in epithelial breast cancer media using Impedance spectroscopy, to test biocompatibility, due to potential in vivo use as a diagnostic aid. It was found that palladium catalyzed silica nanowires were toxic to breast cancer cells, however, nanowires were inert at 1µg/mL concentrations. Additionally a method for direct nanowire integration was developed that allowed for silica nanowires to be grown directly into interdigitated sensing structures. This technique eliminates the need for physical nanowire transfer thus preserving nanowire structure and performance integrity and further reduces fabrication cost. Successful nanowire integration was physically verified using Scanning electron microscopy and confirmed electrically using Electrochemical Impedance Spectroscopy of immobilized Prostate Specific Antigens (PSA). The experiments performed above serve as a guideline to addressing the metallurgic challenges in nanoscale integration of materials with varying composition and to understanding the effects of nanomaterials on biological structures that come in contact with the human body.

Modèles organisationnels et compétences infirmières en gestion de lits

Travail dirigé présenté à la Faculté des sciences infirmières en vue de l’obtention du grade de Maître ès sciences (M.Sc.) en sciences infirmières option formation des sciences infirmières

Biomethane production from macroalgae

Irish brown seaweeds have been identified as a potential bio-resource with potentially high specific methane yields. Anaerobic digestion is deemed the most feasible technology due to its commercial viability for handling such wet feedstock. However, the biomethane potential of seaweed is highly dependent on its chemical composition which can vary by species type, cultivation method, and time of harvest. This study aims to investigate and optimize the process for the production of biomethane from Irish brown seaweeds focusing on the key technology bottlenecks including for seaweed characterization, biomethane potential assessment, optimization of long-term anaerobic digestion and suitable pre-treatment technologies to enhance potential gas yields. Laminaria digitata and Ascophyllum nodosum were tested for seasonal variation. From the characterization and batch digestion of L. digitata, August was found to be the optimal month for harvest due to high organic matter content, low level of ash and ultimately highest biomethane yield. The specific methane yield of 53 m3 CH4 t-1 wwt in August was 4.5 times higher than the yield in December (12 m3 CH4 t-1 wwt), with ash content the key factor in seasonal variation. For A. nodosum, the optimal harvest month was October with polyphenol content found to be a more influential factor than ash. The gross energy yields from both species were evaluated in the range of 116-200 GJ ha-1 yr-1. Continuous digestion trials were subsequently designed for S. latissima and L. digitata to optimize the key digestion parameters. Results from mono-digestion and co-digestion with dairy slurry revealed that both seaweeds could be digested at maximum biomethane efficiency to a loading rate of 4 kg VS m-3 d-1. Accumulation of salt in the digesters was a concern for long term digestion and it was reasoned that suitable pretreatment may be required prior to digestion. Various pre-treatments were subsequently tested on L. digitata to enhance the gas yield. It was found that maceration after hot water washing yielded 25% more specific methane and up to 54% salt removal as compared to untreated L. digitata. The experiments undertaken aim to assist in providing a basic guideline for feasible design and operation of seaweed digesters in Ireland.

Exploring the relationship between patterns of physical activity, sedentary behaviour and cardiometabolic health in middle-aged Irish adults

Background and Study Rationale Being physically active is a major contributor to both physical and mental health. More specifically, being physically active lowers risk of coronary heart disease, high blood pressure, stroke, metabolic syndrome (MetS), diabetes, certain cancers and depression, and increases cognitive function and wellbeing. The physiological mechanisms that occur in response to physical activity and the impact of total physical activity and sedentary behaviour on cardiometabolic health have been extensively studied. In contrast, limited data evaluating the specific effects of daily and weekly patterns of physical behaviour on cardiometabolic health exist. Additionally, no other study has examined interrelated patterns and minute-by-minute accumulation of physical behaviour throughout the day across week days in middle-aged adults. Study Aims The overarching aims of this thesis are firstly to describe patterns of behaviour throughout the day and week, and secondly to explore associations between these patterns and cardiometabolic health in a middle-aged population. The specific objectives are to: 1 Compare agreement between the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and GENEActiv accelerometer-derived moderate-to-vigorous (MVPA) activity and secondly to compare their associations with a range of cardiometabolic and inflammatory markers in middle-aged adults. 2 Determine a suitable monitoring frame needed to reliably capture weekly, accelerometer-measured, activity in our population. 3 Identify groups of participants who have similar weekly patterns of physical behaviour, and determine if underlying patterns of cardiometabolic profiles exist among these groups. 4 Explore the variation of physical behaviour throughout the day to identify whether daily patterns of physical behaviour vary by cardiometabolic health. Methods All results in this thesis are based on data from a subsample of the Mitchelstown Cohort; 475 (46.1% males; mean aged 59.7±5.5 years) middle-aged Irish adults. Subjective physical activity levels were assessed using the IPAQ-SF. Participants wore the wrist GENEActiv accelerometer for 7 consecutive days. Data was collected at 100Hz and summarised into a signal magnitude vector using 60s epochs. Each time interval was categorised based on validated cut-offs. Data on cardiometabolic and inflammatory markers was collected according to standard protocol. Cardiometabolic outcomes (obesity, diabetes, hypertension and MetS) were defined according to internationally recognised definitions by World Health Organisation (WHO) and Irish Diabetes Federation (IDF). Results The results of the first chapter suggest that the IPAQ-SF lacks the sensitivity to assess patterning of activity and guideline adherence and assessing the relationship with cardiometabolic and inflammatory markers. Furthermore, GENEActiv accelerometer-derived MVPA appears to be better at detecting relationships with cardiometabolic and inflammatory markers. The second chapter examined variations in day-to-day physical behaviour levels between- and within-subjects. The main findings were that Sunday differed from all other days in the week for sedentary behaviour and light activity and that a large within-subject variation across days of the week for vigorous activity exists. Our data indicate that six days of monitoring, four weekdays plus Saturday and Sunday, are required to reliably estimate weekly habitual activity in all activity intensities. In the next chapter, latent profile analysis of weekly, interrelated patterns of physical behaviour identified four distinct physical behaviour patterns; Sedentary Group (15.9%), Sedentary; Lower Activity Group (28%), Sedentary; Higher Activity Group (44.2%) and a Physically Active Group (11.9%). Overall the Sedentary Group had poorer outcomes, characterised by unfavourable cardiometabolic and inflammatory profiles. The remaining classes were characterised by healthier cardiometabolic profiles with lower sedentary behaviour levels. The final chapter, which aimed to compare daily cumulative patterns of minute-by-minute physical behaviour intensities across those with and without MetS, revealed significant differences in weekday and weekend day MVPA. In particular, those with MetS start accumulating MVPA later in the day and for a shorted day period. Conclusion In conclusion, the results of this thesis add to the evidence base regards an optimal monitoring period for physical behaviour measurement to accurately capture weekly physical behaviour patterns. In addition, the results highlight whether weekly and daily distribution of activity is associated with cardiometabolic health and inflammatory profiles. The key findings of this thesis demonstrate the importance of daily and weekly physical behaviour patterning of activity intensity in the context of cardiometabolic health risk. In addition, these findings highlight the importance of using physical behaviour patterns of free-living adults observed in a population-based study to inform and aid health promotion activity programmes and primary care prevention and treatment strategies and development of future tailored physical activity based interventions.

Diet quality is associated with obesity and hypertension in Australian adults: a cross sectional study.

BACKGROUND: Poor diet, characterized by a low diet quality score, has been associated with greater prevelence of obesity and hypertension. However, the evidence is inconsistent across diet quality scores and by sex. The aim was to investigate the relationship between diet quality and obesity and hypertension. METHODS: Adults (n = 4908; age 45.2 ± 0.24 years) were included from the cross-sectional Australian Health Survey 2011-2013. Two 24-h dietary recalls were used to derive the dietary guideline index (DGI) and recommended food score (RFS). Logistic regression investigated relationships between diet quality score and odds ratio of obesity, hypertension and obesity-associated hypertension. RESULTS: In the highest tertile of DGI, but not RFS, individuals were less likely to be obese (men: OR 0.64, CI: 0.45, 0.92, P-trend = 0.014; women: 0.68, 0.48, 0.96, P-trend = 0.025) and to have central adiposity (men: 0.68, 0.48, 0.97, P-trend = 0.030; women: 0.53, 0.37, 0.77, P-trend = 0.001) compared with the lowest tertile. Men, but not women, in the highest tertile of DGI and RFS were less likely to be hypertensive (DGI: 0.56, 0.37, 0.85, P-trend = 0.006; RFS: 0.62, 0.41, 0.94, P-trend = 0.021) compared with the lowest tertile. In men with obesity, but not normal weight men or women, those in the highest tertile of DGI were less likely to be hypertensive (0.53, 0.36, 0.78, P-trend = 0.001) compared with the highest tertile. CONCLUSIONS: Higher diet quality, as estimated using DGI, was associated with lower odds ratio of obesity in men and women. Odds ratio of hypertension was lower in men, but not women, with a high diet quality score compared with a low score, while obesity-associated hypertension was only associated with diet quality score in men with obesity. Longitudinal studies are needed to evaluate whether diet quality predicts risk of obesity and hypertension.

Diet quality and telomere length in older Australian men and women.

PURPOSE: Telomere length is a biomarker of cellular ageing, with longer telomeres associated with longevity and reduced risk of chronic disease in older age. Consumption of a healthy diet may contribute to longevity via its impact on cellular ageing, but studies on diet and telomere length to date have been limited and their findings equivocal. The aim of this study was to examine associations between three indices of diet quality and telomere length in older men and women. METHODS: Adults aged 57-68 years participating in the Wellbeing, Eating and Exercise for a Long Life (WELL) study in Victoria, Australia (n = 679), completed a postal survey including an 111-item food frequency questionnaire in 2012. Diet quality was assessed via three indices: the Dietary Guideline Index, the Recommended Food Score, and the Mediterranean Diet Score. Relative telomere length was measured by quantitative polymerase chain reaction. Associations between diet quality and telomere length were assessed using linear regression adjusted for covariates. RESULTS: After adjustment for age, sex, education, smoking, physical activity, and body mass index (BMI), there were no significant associations between diet quality and relative telomere length. CONCLUSIONS: In a sample of older adults residing in Victoria, Australia, men and women aged 57-68 years with better-quality diets did not have longer telomeres. Further investigation in longitudinal studies will determine whether diet can influence telomere length over time in an ageing population.

Psychosocial issues in evidence-based guidelines on inflammatory bowel diseases: a review.

AIM: To study statements and recommendations on psychosocial issues as presented in international evidence-based guidelines on the management of inflammatory bowel diseases (IBD). METHODS: MEDLINE, guidelines International Network, National Guideline Clearing House and National Institute for Health and Care Excellence were searched from January 2006 to June 30, 2013 for evidence-based guidelines on the management of IBD. RESULTS: The search yielded 364 hits. Thirteen guidelines were included in the review, of which three were prepared in Asia, eight in Europe and two in the United States. Eleven guidelines made statements and recommendations on psychosocial issues. The guidelines were concordant in that mental health disorders and stress do not contribute to the aetiology of IBD, but that they can influence its course. It was recommended that IBD-patients should be screened for psychological distress. If indicated, psychotherapy and/or psychopharmacological therapy should be recommended. IBD-centres should collaborate with mental health care specialists. Tobacco smoking patients with Crohn's disease should be advised to quit. CONCLUSION: Patients and mental health specialists should be able to participate in future guideline groups to contribute to establishing recommendations on psychosocial issues in IBD. Future guidelines should acknowledge the presence of psychosocial problems in IBD-patients and encourage screening for psychological distress.

Guidelines for developing and reporting machine learning predictive models in biomedical research : a multidisciplinary view

BACKGROUND: As more and more researchers are turning to big data for new opportunities of biomedical discoveries, machine learning models, as the backbone of big data analysis, are mentioned more often in biomedical journals. However, owing to the inherent complexity of machine learning methods, they are prone to misuse. Because of the flexibility in specifying machine learning models, the results are often insufficiently reported in research articles, hindering reliable assessment of model validity and consistent interpretation of model outputs.

OBJECTIVE: To attain a set of guidelines on the use of machine learning predictive models within clinical settings to make sure the models are correctly applied and sufficiently reported so that true discoveries can be distinguished from random coincidence.

METHODS: A multidisciplinary panel of machine learning experts, clinicians, and traditional statisticians were interviewed, using an iterative process in accordance with the Delphi method.

RESULTS: The process produced a set of guidelines that consists of (1) a list of reporting items to be included in a research article and (2) a set of practical sequential steps for developing predictive models.

CONCLUSIONS: A set of guidelines was generated to enable correct application of machine learning models and consistent reporting of model specifications and results in biomedical research. We believe that such guidelines will accelerate the adoption of big data analysis, particularly with machine learning methods, in the biomedical research community.

Evaluación de las causas de los eventos adversos o incidentes que afectan la seguridad del paciente, en el hospital central de la policía de enero 2012 a diciembre 2013

TITULO DEL TRABAJO: Evaluación de las causas de los eventos adversos o incidentes que afectan la seguridad del paciente, en el hospital central de la policía de enero 2012 a diciembre 2013. OBJETIVO: Determinar y analizar la causa raíz de los principales factores de riesgo que afectan la seguridad del paciente que puedan ocasionar eventos adversos en la atención de los pacientes, con el uso de la teoría de restricciones TOC en el Hospital Central de la Policía HOCEN. MATERIALES Y METODO: Se realizó una investigación descriptiva de naturaleza mixta – cuantitativa de tipo correlacional, la población es la totalidad de pacientes atendidos en el hospital de la policía entre enero de 2012 a diciembre de 2013, en el cual se presentaron un total de 189 eventos adversos los cuales sirvieron de objeto a esta investigación, la recolección de datos se realizó por medio de tablas de Excel 2010, posterior a esto se exporto la información al software de IBM SPSS Statistics 19 donde se analiza la información arrojando datos descriptivos y tablas de frecuencia. Finalmente haciendo uso de la Teoría de restricciones TOC se identificó la causa raíz para la ocurrencia de eventos adversos y plantear una intervención estratégica que promueva un sistema efectivo de seguridad del paciente en pro de la búsqueda de la mejora continua. RESULTADOS: Se analizaron 189 eventos adversos, de los cuales 89 fueron reportados en el turno de la noche, seguido por el turno de la mañana con 57, el turno tarde con 27, 28 eventos que no registraron horario, el servicio con mayor ocurrencia es el de medicina interna con 25 eventos, y finalmente la caída de pacientes, lo relacionado con medicamentos, nutriciones y accesos vasculares son los eventos con mayor incidencia. CONCLUSIONES: Se pudo concluir que es necesario que los procesos de seguridad del paciente deben tener un lineamiento directo desde la dirección de la organización permitiendo que las mejoras sean de inmediata aplicación, también es importante generar en el personal una actitud de compromiso frente al proceso de mejora, hay que redefinir las políticas institucionales ya que se concluyó por medio de la teoría de restricciones TOC que el principal factor para la ocurrencia de eventos adversos son las multitareas que el personal tiene que realizar en el proceso de atención.

Supervivencia y mortalidad por tipo de terapia de reemplazo renal, en pacientes con enfermedad renal crónica terminal, en una cohorte de pacientes asegurados en Colombia

En Colombia se ha podido establecer que la incidencia y mortalidad de la Enfermedad Renal Crónica Terminal continúan en aumento en los últimos 6 años a pesar de las estrategias de intervención para prevención y control de la enfermedad implementadas nivel nacional. Este trabajo busca establecer la línea de base para la población asegurada en Colombia, frente a la supervivencia de pacientes en terapia de remplazo renal (TRR).

Evaluación de las propiedades clinimétricas de la escala POSAS y su aplicación en pacientes de la Fundación del Quemado en Bogotá

•Objetivos: Se tradujo, adaptó y evaluaron las propiedades clinimétricas de la escala POSAS en pacientes con cicatrices hipertróficas (CHT) y queloides (CQ) cómo secuelas de quemadura, que fueron manejados con Z plastias en la Fundación del Quemado en Bogotá (Colombia), entre Junio de 2015 a Abril de 2016. •Métodos: Estudio de evaluación de las propiedades clinimétricas de una escala. Se hizo una traducción y adaptación transcultural siguiendo el método de traducción-retrotraducción. Se aplicó el instrumento adaptado a cincuenta y dos pacientes (n=52) antes y después de la intervención quirúrgica. Se evaluó la validez, confiabilidad, sensibilidad al cambio y la utilidad de la escala. •Resultados: Se hallaron diferencias significativas en los puntajes obtenidos del Observador y del Paciente, antes y después de la intervención quirúrgica (p<0.000); a excepción de prurito. La escala POSAS demostró ser altamente confiable para la Escala del Observador y del Paciente (α = 0.912 y 0.765). Hubo alta correlación en las evaluaciones de dos observadores para las variables ordinales de la Escala del Observador (r>0.6). La concordancia entre las evaluaciones de dos observadores para las variables categóricas de la Escala del Paciente fue buena para la evaluación antes de la intervención para pigmentación y relieve (κ>0.61). Se demostró que el instrumento es capaz de detectar cambios clínicos en el tiempo (p<0.0000), a excepción de prurito (p= 0.271). •Conclusiones: La escala POSAS demostró ser un instrumento válido, confiable y útil para evaluar la calidad de la cicatriz en pacientes con CHT y CQ cómo secuelas de quemadura.

Conducta médica versus escala modificada Wood en bronquiolitis aguda

El diagnóstico y clasificación de la severidad de la bronquiolitis se basan en la historia clínica y el examen físico. Actualmente existe una variabilidad en el ámbito clínico en el uso de los predictores de hospitalización de estos pacientes. En Colombia debido al número limitado de camas hospitalarias, es importante diferenciar y clasificar adecuadamente el lugar de manejo para cada paciente, según sus características clínicas, antecedentes y rasgos sociodemográficos. De esta manera se evitará la morbilidad y mortalidad de los pacientes por esta causa, se dará un manejo oportuno y se optimizará un recurso limitado. La escala de severidad clínica de asma modificada de Wood (M-WCAS), combina síntomas y signos encontrados al examen físico para clasificar la severidad de la bronquiolitis aguda. Esta escala fue validada en Colombia en el año 2013 y podría ser un instrumento que apoye la toma de decisiones clínicas de estos pacientes en cuanto al lugar de manejo.

Asociación entre la escala de riesgo Framingham y el puntaje de calcio coronario

Introducción: Entre las diferentes herramientas clínicas para evaluar la presencia de enfermedad coronaria mediante puntajes, la más usada es la Escala de Riesgo cardiovascular de Framingham. Desde hace unos años, se creó el puntaje de calcio coronario el cual mide el riesgo cardiovascular según la presencia de placas ateromatosas vistas por tomografía computarizada. Se evaluó la asociación entre la escala de Framigham y el puntaje de calcio coronario en una población de sujetos sanos asintomáticos. Metodología: Se realizó un estudio transversal para evaluar la asociación entre el puntaje de calcio coronario y la escala de Framingham en sujetos asintomáticos que se practicaron exámen médico preventivo en la Fundación Cardioinfantil- Instituto de Cardiología (FCI-IC) en el periodo comprendido entre 1 de Julio 2011 hasta el 31 de octubre de 2015. Resultados: Se evaluaron 262 pacientes en total. La prevalencia de riesgo cardiovascular fue bajo en un 77.86% de la población, medio en 18.70% y alto en 3.44%, según la escala de Framingham. El riesgo cardiovascular según el puntaje de Calcio coronario fue nulo 70.99%, bajo en 21.75%, medio en 4.19%, severo en 3.05%. Se encontró una asociación entre ambos puntajes para riesgo estadísticamente significativa (p0,00001) Discusión: El riesgo cardiovascular establecido por escala de Framingham se relaciona de forma significativa con la presencia de placas aterioscleróticas. El estudio demostró que en una muestra de sujetos asintomáticos, hay una alteración estructural coronaria temprana.

Impedancias basales registradas durante la denervación renal por radiofrecuencia en pacientes con hipertensión arterial resistente

Objetivo: Determinar diferencias en las impedancias basales registradas durante los procedimientos de denervación renal por radiofrecuencia de los pacientes sometidos a este procedimiento en la Fundación Cardioinfantil de Bogotá durante los años 2012 a 2015. Materiales y métodos: Estudio observacional, analítico de corte retrospectivo, donde se analizaron todas las impedancias basales medidas durante los procedimientos de denervación renal, buscando diferencias significativas entre los segmentos de las arterias intervenidas, estratificados en proximal, medio distal y superior, lateral, inferior u ostial. Con seguimiento a los pacientes a tres, seis y doce meses en cuanto a presión arterial de consultorio. Resultados: Se evaluaron 150 puntos de denervación renal exitosos, correspondientes a 23 arterias renales de 11 procedimientos. La mediana de edad fue 56 años. Al realizar un modelo de regresión lineal no se encontró ninguna diferencia estadísticamente significativa entre las impedancias de ninguno de los segmentos de las arterias ni sitios anatómicos. Se documentó disminución de presión arterial sistólica a tres meses, seis meses y doce meses de 14 mmHg (RIQ 10-33mmHg), 21 mmHg (RIQ 12-42mmHg) y 19 mmHg (RIQ 11-42 mmHg) respectivamente

Primary Joint Arthroplasty Surgery: Is the Risk of Major Bleeding Higher in Elderly Patients? A Retrospective Cohort Study

Increased risk of bleeding after major orthopedic surgery (MOS) has been widely documented in general population. However, this complication has not been studied in elderly patients. The purpose of this study is to determine whether the risk of major bleeding after MOS is higher in elderly patients, compared with those operated at a younger age. Methods: This retrospective cohort study included total hip and total knee arthroplasty patients operated during 5 consecutive years. The main outcome was the occurrence of major bleeding. Patients with other causes of bleeding were excluded. Relative risks (RRs) and confidence intervals (CIs) were calculated, anda multivariate analysis was performed. Results: A total of 1048 patients were included, 56% of patients were hip arthroplasties. At the time of surgery, 553 (53%) patients were older than 70 years. Patients aged >70 years showed an increased risk of major bleeding (RR: 2.42 [95% CI: 1.54-3.81]). For hip arthroplasty, the RR of bleeding was 2.61 (95%CI: 1.50-4.53) and 2.25 (95% CI: 1.03-4.94) for knee arthroplasty. After multivariate analysis, age was found to be independently associated with higher risk of major bleeding. Conclusion: According to European Medicines Agency criteria, patients aged 70 years are at a higher risk of major bleeding after MOS, result of a higher frequency of blood transfusions in this group of patients. Standardized protocols for blood transfusion in these patients are still required.