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Microbiological surveillance in the Mid-West of Ireland
No full textMicrobial surveillance is crucial for tracking the emergence and prevalence of infectious diseases and antimicrobial resistance (AMR), enabling timely interventions to be made and health policies to be informed. The aim of this thesis is to provide a detailed epidemiological analysis of microbial pathogens and AMR in our region. This thesis presents a comprehensive analysis of the microbial pathology in the Mid-West region of Ireland over the past two decades, covering aspects of all three branches of One Health (humans, animals and the environment). Over the course of seven studies, retrospective data from the laboratory information system were extracted and analysed, looking for trends and patterns in the data. The first study (chapter two) explored the epidemiology of the fungal pathogens that cause skin, hair and nail infections. An interesting trend was identified: fungal infections from animals became less common, and there was a corresponding increase in infections from human source (less than 35% to more than 75%). The second study (chapter three) looked at the diagnostic methods commonly used around Ireland; limitations were found (many laboratories have been outsourcing testing, susceptibility testing is not being performed, and modern PCR tests have not been introduced), A roadmap was provided for optimising this service. The third study (chapter four) was the first national study of public and private drinking water, and the first drinking water AMR study where all enterobacterales were included. Some concerning organisms were detected such as Yersinia enterocolitica. This organism was shown to be challenging to distinguish from other Yersinia species, so a follow-up study was performed (chapter five) which provides an analysis of Yersinia enterocolitica detection in our region, as well as a commentary on the detection and identification platforms available, and a framework for clinical laboratories to follow in order to improve detection.The fifth study of this thesis (chapter six) investigated five specimens that are used in our hospital to help manage maternal sepsis (blood culture, urine, throat vaginal and placental swabs). Placenta swabs (an uncommonly requested specimen in other centres) were found to be useful in this context, by detecting pathogens that frequently cause perinatal infections while other specimens were often sterile or contained commensal organisms. In the sixth study (chapter seven), the epidemiology of neonatal bacteraemia was analysed. Details were available for 170 bacteraemia cases that occurred over a ten year period. Risk factors for neonatal bloodstream infection were reported for the first time from an Irish patient cohort. Finally, a large One Health study (chapter eight) of antimicrobial resistance among a variety of clinical specimens from humans and animals was performed over a twelve year period. This study found a general decrease in both the use of antimicrobials and the resistance to those antimicrobials in that timeframe. Conversely, one antimicrobial showed an increase in both consumption and resistance. This provided important evidence for the utility of antimicrobial stewardship measures.The studies performed in this thesis span a wide spectrum of organisms and their characteristics, including both bacteria and fungi, across all three domains of One Health: human medicine, animal medicine and the environment. Not only do they provide measurable data which in itself is an important function of retrospective epidemiological studies, but diagnostic deficiencies are pointed out, new and improved platforms are discussed and recommended, and future directions are proposed.</p
Modelling pain in population-based cohort studies: Biases, causal inference, and latent class methodologies
No full textPopulation-based cohort studies present unique opportunities to investigate research questions in areas such as population health and well-being. Addressing challenges in the statistical modelling of pain in older adults using cohort studies is the main goal of this thesis, motivated by two large cohort studies of ageing: the Irish Longitudinal Study on Ageing (TILDA) and the American Health and Retirement Study (HRS).Firstly, the presence of pain-related attrition bias, mortality bias, and measurement bias due to differences in reporting styles (reporting heterogeneity) in TILDA is investigated. Evidence of mortality bias and reporting heterogeneity is found. Sex and socioeconomic disparities in pain previously reported in other countries are also observed in TILDA. Next, the causal effect of pain exposure on 20-year mortality in American older adults is estimated using HRS data. Propensity score methods are applied to adjust for measured confounding bias identified using a directed acyclic graph. Results suggest that pain likely causes a modest increase in mortality hazard, though the results are also compatible with no effect. Additionally, modifiable common causes of both pain and mortality are highlighted as potential targets for intervention.Issues around the measurement of pain are also addressed. While pain is often modelled using a single measure such as pain intensity, it is desirable to identify a more holistic measure that incorporates multiple different aspects of pain experience. Latent class analysis (LCA) could be used for this task, however LCA model selection is particularly challenging for large datasets. The adaptation of fit indices from structural equation modelling for use with LCA is proposed to aid LCA model selection. The performance of the proposed indices is assessed using two simulation studies, and the indices show some potential when interpreted using an “elbow” rule. Finally, the proposed fit indices are applied to aid the development of an LCA model using various pain-related variables in the HRS dataset. Three distinct pain experience latent classes are identified, characterised by different patterns of pain impact and pain medication use. The latent classes are also found to differ across sociodemographic characteristics, with female sex and indicators of poorer socioeconomic background most common in the highest impact pain class.In summary, this thesis addresses multiple challenges related to biases, causal inference, and latent class methodologies, developing approaches to strengthen the pain research evidence base. Findings are discussed within the context of current literature, and directions for future research are outlined.</p
A Systematic review and meta-analysis of an angiotensin receptor–neprilysin inhibitor in patients using a durable left ventricular assist device
No full textIntroduction: Sacubitril/valsartan is an angiotensin receptor–neprilysin inhibitor (ARNI) drug used to treat patients with heart failure and has shown improvement in outcomes. Different studies reported the use of an ARNI in patients using left ventricular assist devices (LVADs). However, there are limited data on the use of ARNIs in this population. We aimed to assess the efficacy of ARNIs in LVAD patients. Methods: A systematic search was performed in PubMed, Scopus, Web of Science, Embase, and Cochrane from inception to November 2024. We used all relevant words for “ARNI” and “LVAD” to search, and we included studies that assessed ARNIs in patients with LVAD. Efficacy and safety outcomes were extracted from the included studies. R software version 4.4.2 was used for a meta-analysis. Results: Seven studies totaling 249 patients were included. The ARNI was found to be effective in improvements from baseline in the New York Heart Association (NYHA), B-type natriuretic peptide (BNP) (mean = −630.07 pg/mL, 95% CI [−1113.13, −147.01]), diuretic dose (furosemide equivalents) (mean= −76.05 mg/day, 95% CI [−145.11, −6.99]), left ventricular end-diastolic diameter (LVEED) (mean = −7.3 mm, 95% CI [−11.4, −3.1]), and left ventricular ejection fraction (LVEF) (mean =5, 95% CI [3.52, 6.48]). No improvement was found in the creatinine (Cr) level. However, a slight increase in the potassium level was noticed (mean= 0.17 mEq/L, 95% CI [0.02, 0.34]). The overall mortality in patients using the ARNI was 5%, 95% CI [0.00, 20], and discontinuation was found in 25%, 95% CI [0, 100]. Conclusions: The ARNI improved several cardiac structural and hemodynamic parameters in patients on LVAD support.</p
On the influence of pressure drop and fluid-structure interaction on the hemodynamics of arteriovenous fistula
No full textChronic kidney disease (CKD) is a prevalent global health concern, affecting millions worldwide and often progressing to end-stage renal disease (ESRD), necessitating interventions like hemodialysis (HD). Arteriovenous fistulas (AVFs) are commonly created to facilitate HD due to their advantages over alternative methods. However, a significant percentage of AVFs fail to mature successfully, leading to complications. Understanding the hemodynamic factors influencing AVF outcomes is crucial, particularly in addressing issues like stenosis, intimal hyperplasia (IH), disturbed shear stress and negative remodelling.This research aims to bridge existing gaps in the numerical modelling of AVF hemodynamics, focusing on three critical areas: accurately simulating the pressure drop across the AVF anastomosis, the impact of compliance on wall shear stress (WSS)-based parameters, and the time-dependant impact of arterial flow conditions on venous material properties. The thesis includes an extensive review of existing research on AVF hemodynamics, numerical modelling techniques, and experimental methodologies, setting the stage for subsequent investigations. It validates the numerical approach through ex-vivo displacement data analysis and highlights previous validation studies adopting similar numerical methodologies, thus appropriately representing real-world conditions. The pressure distribution across AVFs at the time of surgery is assessed, revealing discrepancies between in-vivo measurements and numerical simulations. Insights gained highlight the need for improved modelling techniques to replicate realistic pressure drops accurately. Furthermore, a comparative evaluation of patient-specific computational models was conducted, comparing conventional Computational Fluid Dynamics with Fluid-Structure Interaction simulations. Highlighting the importance of personalised assessments and refined computational modelling techniques.This research also explores ex-vivo perfusion of vascular tissue as a means of analysing morphometric changes induced by controlled hemodynamics. This work underscores the time-dependent nature of venous tissue adaptation, advocating for dynamic material models in AVF simulations to accurately capture tissue responses over extended durations.Overall, this research contributes to our understanding of AVF hemodynamics and venous tissues material properties response to increased flow and pressure. Identified gaps and future research directions aim to advance the field of AVF characterisation and treatment, ultimately improving outcomes for patients with CKD and ESRD.</p
A novel approach to determining aircraft stability derivatives in extreme flight conditions
No full textThe concept of Aircraft Stability first originated in 1911 with the creation of the aircraft equations of motion. These expressions detailed the aircraft’s dynamics in flight and were formulated using parameters termed as aircraft stability derivatives. The aircraft stability derivative is a direct measure of an aircraft’s response to a disturbance. It is presented in the form of Cmα , for example, which denotes the pitching moment response to change in angle of attack. This formulation of aircraft stability was created as a linearized approximation and proved successful for aircraft of that generation. However, with the advances toward flight in more extreme regimes, it suffered as a consequence of non-linear phenomena within that envelope.The aim of this research project is to merge the fields of aircraft stability, computational fluid dynamics (CFD) and high angle of attack aerodynamics in the investigation of aircraft stability derivatives. Employing a combination of low-speed wind tunnel experiments and sub-scale and free flight CFD simulations, the project focuses on the application of forced oscillations to a generic aircraft geometry. This aircraft is known as the Standard Dynamics Model (SDM) and was established in 1978 for the purpose of comparative dynamic wind tunnel testing.Within this thesis, the specification of a frequency and amplitude-based methodology is explored under the premise of enhancing the stability derivative determination capability in extreme orientations. To date, this appears to have only been explored in the linear regime, based on information available in the public domain. In examining the forced oscillation methodology and the frequency effects upon the aircraft stability derivative resolution, it was found that forcing frequency played a pivotal role at high angles of attack. In the case of the Standard Dynamics Model, an oscillation of 5 Hz was required when an angle of attack of 15° was exceeded in order to accurately capture the high frequency content associated with high angle of attack phenomena. The recommendation is to perform frequency assessments prior to employment of this methodology should it be employed at high angles of attack. With this knowledge an accurate forcing frequency may be specified in order to isolate the dynamics at play and obtain the most accurate representation of the aircraft’s stability. In doing so, extend the traditional forced oscillation methodology successfully into the high angle of attack regime.</p
Enabling fluorine-free lithium-ion capacitors and lithium-ion batteries for high-temperature applications by the implementation of lithium bis(oxalato)borate and ethyl isopropyl sulfone as electrolyte
No full textA novel fluorine-free electrolyte comprising a solution of lithium bis(oxalato)borate in ethyl isopropyl sulfone is presented. It is characterized by its safety and non-toxic properties, along with the capability to effectively suppress the anodic dissolution of aluminum. Successful high-temperature application of this electrolyte in combination with various capacitor- and battery-like electrode materials is shown. Further utilization in a lithium-ion capacitor and a lithium-ion battery is demonstrated. To the best of the knowledge, the lithium-ion capacitor presented in this work represents the first entirely fluorine-free device suitable for high-temperature applications. When operating at 60 °C, this device delivers a maximum energy output of 169 Wh kg−1 AM at a power of 200 W kg−1 AM and even 80 Wh kg1 AM at 10 kW kg-1 AM, along with the ability to retain 80% of its initial capacitance after 3500 cycles at 5 A g−1. As such, this novel electrolyte is a promising alternative to conventional fluorine-containing configurations since its performance is capable to match or even surpass that of most similar laboratory-scale LICs</p
Fluorine-free lithium-ion capacitor with enhanced sustainability and safety based on bio-based ƴ-Valerolactone and lithium bis(oxalato)borate electrolyte
No full textIn this work, the properties of a novel electrolyte based on the combination of bio-based ƴ-valerolactone (GVL) solvent with lithium bis(oxalato)borate (LiBOB) salt and its use for lithium-ion capacitors (LICs) are presented. It is shown that the 1 m LiBOB in GVL electrolyte displays good transport properties, high thermal stability, and the ability to prevent anodic dissolution. Its impact on the performance of both battery-type and capacitive-type electrodes is evaluated. In this regard, special attention is paid to the filming properties associated with LiBOB and GVL decomposition at the electrode surfaces. To the best of the authors’ knowledge, the full-cell devices assembled in this study are the first example of a fluorine-free LIC. These devices exhibit a favorable energy-to-power ratio, delivering 80 Wh kg−1 AM at 10 000 W kg−1 AM along with excellent cycling stability, retaining 80% of the initial capacitance after 25 000 cycles. Furthermore, post-mortem analysis of the LIC electrodes is conducted to gain deeper insights into the degradation mechanisms within the device.</p
Labral repair, reconstruction, and augmentation improve postoperative outcomes in patients with irreparable or hypoplastic labra: A systematic review
No full textPurpose: To review the postoperative outcomes of arthroscopic surgical options in treating irreparable and hypoplastic labrum of the hip. Methods: Three online databases (PubMed, MEDLINE, and EMBASE) were searched from database inception to June 27, 2023 to identify literature on treatment strategies for hypoplastic/irreparable acetabular labrum. Data pertaining to classification of irreparable tears or labral hypoplasia, indication for surgery, description of treatment, radiographic findings, and clinical outcomes were recorded and described. The methodological quality of included studies was assessed by the Methodological Index for Non-Randomized Studies (MINORS) criteria. Results: Seven level IV case series, eleven level III retrospective cohort studies, and two level II prospective cohort studies comprising 1937 patients were included for analysis. Studies were divided into an irreparable labral group comprising 1002 patients and a hypoplastic labral group comprising 935 patients. Treatments included repair, augmentation, or reconstruction. In the irreparable group, 12 studies recorded improvement of modified Harris Hip Score (mHHS) with preoperative scores ranging from 50.3 to 67.3 and postoperative scores ranging from 76.2 to 95.0. The rate of conversion to total hip arthroplasty (THA) and rate of revision arthroscopy were 6.6% and 5.9%, respectively across all studies. In the hypoplastic group, two studies that focused on repair noted no sta?tistical difference in mHHS for repair in hypoplastic labrum vs repair in non-hypoplastic labrum. One study showed that there was a difference in post-operative mHHS for labral repair for hypoplastic vs non-hypoplastic labrum, with repair in non-hypoplastic labrum showing superior mHHS (p < 0.001). Conclusion: The findings of this review suggest that treatment of irreparable labra with reconstruction or augmentation results in improved patient-reported outcome measures (PROMs). For the hypoplastic labrum, primary repair also results in improvement in PROMs. Future studies focusing on the hypoplastic labra alone with an appropriate control group, rather than irreparable labral tears, are needed to properly assess patient outcomes and guide surgical indications.</p
The opportunities and challenges of using online social platforms after pregnancy loss: A systematic review of qualitative research
No full textOnline social platforms (e.g. social media, online forums) can serve as important sources of support for individuals that have experienced pregnancy loss. However, these platforms also pose potential risks to users (including online victimization and misinformation) which can limit their sense of safety online. This paper argues that interdisciplinary work can play a central role in supporting safer online experiences after pregnancy loss. To critically consider implications for future research in this context, we systematically reviewed existing qualitative research investigating online social platform experiences among this population. We present a thematic synthesis of the findings from 28 studies, in which we identify opportunities and challenges experienced by users after pregnancy loss, and techniques that they used to manage these challenges. We then propose a series of recommendations for how future researchers should further examine and address the issues identified in past literature in order to support safer online platform engagement among this population.</p
Social capital as a barrier to innovation: The mediating role of job autonomy
No full textWhile social capital has been extensively studied for its positive effects, its potential risks have received limited attention. This research addresses this gap by examining how social capital constrains job autonomy and subsequently hinders product innovation. Data were collected from 1,007 respondents at 102 Chinese high-tech small and medium-sized enterprises (SMEs), and analyzed using multilevel structural equation modeling. Our findings highlight that social capital negatively impacts product innovation by reducing job autonomy. From a managerial perspective, the findings identify the need for managers to carefully evaluate the trade-offs between the benefits and risks of fostering social capital in the workplace</p