Physical modeling of vortical cross-step filtration in the oral cavity of American paddlefish (Polyodon spathula)

This thesis explores the filter-feeding mechanisms of the American paddlefish, Polyodon spathula. The data indicate that paddlefish use a filtration method termed cross-step filtration, which utilizes vortices formed behind the branchial arches by the incoming water flow. Videos of these vortices were obtained and quantified for the first time inside the oral cavities of preserved paddlefish. Since the paddlefish can move the branchial arches within the oral cavity, the effects of changing branchial arch angle on vortex characteristics were studied in 3D models. The vortices in three models with different arch angles were quantified. The data demonstrated that a change in arch angle affects vortex characteristics in the 3D models. Therefore, paddlefish could be changing the angles of their branchial arches to influence the flow within their oral cavities

Electronic risk assessment for venous thromboembolism: investigating physicians' rationale for bypassing clinical decision support recommendations.

Objective: The underutilisation of venous thromboembolism (VTE) prophylaxis is still a problem in the UK despite the emergence of national guidelines and incentives to increase the number of patients undergoing VTE risk assessments. Our objective was to examine the reasons doctors gave for not prescribing enoxaparin when recommended by an electronic VTE risk assessment alert. Design: We used a qualitative research design to conduct a thematic analysis of free text entered into an electronic prescribing system. Setting: The study took place in a large University teaching hospital, which has a locally developed electronic prescribing system known as PICS (Prescribing, Information and Communication System). Participants: We extracted prescription data from all inpatient admissions over a 7-month period in 2012 using the audit database of PICS. Intervention: The completion of the VTE risk assessment form introduced into the hospital-wide electronic prescribing and health records system is mandatory. Where doctors do not prescribe VTE prophylaxis when recommended, they are asked to provide a reason for this decision. The free-text field was introduced in May 2012. Primary and Secondary Outcome Measures: Free-text reasons for not prescribing enoxaparin when recommended were thematically coded. Results: A total of 1136 free-text responses from 259 doctors were collected in the time period and 1206 separate reasons were analysed and coded. 389 reasons (32.3%) for not prescribing enoxaparin were coded as being due to 'clinical judgment'; in 288 (23.9%) of the responses, doctors were going to reassess the patient or prescribe enoxaparin; and in 245 responses (20.3%), the system was seen to have produced an inappropriate alert. Conclusions: In order to increase specificity of warnings and avoid users developing alert fatigue, it is essential that an evaluation of user responses and/or end user feedback as to the appropriateness and timing of alerts is obtained

An IPA investigation into the experience of a hypnobirthing birth

A Portfolio submitted to the University of Wolverhampton in partial fulfilment of the Practitioner Doctorate in Counselling Psychology.Background: Pregnancy and birth pose significant emotional and physical challenges to birthing people. The prevalence of psychological trauma due to birth has been reported to occur in 7% of the birthing population, with up to 48% of those who have birthed reportedly finding birth as traumatic. The hypnobirthing method is gaining significant popularity and aims to improve the birth experience by reducing the need for medical intervention, increasing feelings of empowerment, control, and feelings of calm, as well as increasing birth partner support. Currently, no research is available on the subjective experience of a hypnobirthing birth that is traumainformed. We must understand more ways to protect birthing people from psychological trauma, and as such, the research aims to explore the experience of utilising this method for birth. Methods: Five participants were self-selected after approaching a local Katharine Graves hypnobirthing Facebook group. Semistructured interviews were conducted up to 6 months after birth. Interviews were analysed using an IPA method to understand the idiographic lived experience of participants. Results: Four superordinate themes were identified: Education protects the birthing process and increases coping; Choice empowers; ‘Rules’ or ‘guidance’ a self-perception; Labour and the ‘mother’ in societal discourse. Conclusions: The birthing people in this study reported that their educative experience helped to reduce fear, and increase their empowerment and perceived coping going into the birth experience. Their ability to engage with the hypnobirthing method appeared affected by their perception of it as ‘guidance’ or ‘rules’ and their feelings of support in the labour room. There were reflections on how the method interacts with the more general societal discourse around labour. Implications: Hypnobirthing antenatal preparation may help improve the labour experience and reduce the risk of psychological trauma following birth. However, the study points to important factors that should be considered. Counselling and Clinical Psychologists in Perinatal and Maternal Mental Health Services, hypnobirthing practitioners and antenatal educators are best placed to utilise the findings of this research and incorporate them into both their antenatal preparation delivery and training, as well as the formulations of service user birth trauma

Evaluating a Social Media Campaign for a Parent Educational Video on Bronchiolitis

Bronchiolitis, or lower airway swelling, is a common cause of pediatric hospital admissions. Parents have expressed wishes for more information regarding bronchiolitis but had difficulty finding reliable information, suggesting the need for more effective and easily accessible information resources. Knowledge translation (KT) tools like videos provide research-based information and may be conveniently disseminated to large audiences through social media. The purpose of this project was to evaluate the effectiveness of a social media campaign to promote a video on bronchiolitis. A social media campaign was conducted from 14 October to 30 November 2019. User interactions were recorded for the Facebook and Twitter accounts, website, and YouTube of Evidence in Child Health to Enhance Outcomes (ECHO), Alberta Research Centre for Health Evidence (ARCHE), and Translating Emergency Knowledge for Kids (TREKK). Baseline metrics were collected from 1 August to 30 September 2019 and post-campaign metrics were collected from 1 December 2019 to 31 March 2020. Mean monthly changes, standard deviations, and percent changes between periods were generated for the baseline, campaign, and post-campaign periods. Overall, there was a visible increase in user interactions throughout the campaign period. There was an overall downward trend in user interactions following the campaign. These findings suggest that social media may be a useful method of KT tool dissemination when consistently used. The downward trend post-campaign highlights the need for further research to investigate methods to maintain continuous interaction following a campaign

The influence of topographically complex slopes on deepwater processes and stratigraphic architecture

Topographically complex slope to basin floor profiles are increasingly recognised in modern seafloor, seismic reflection and outcrop datasets, and range from simple slope profiles, through stepped slopes with high gradient ramps linking low gradient steps, to slopes with 3D enclosed minibasins linked by tortuous corridors. This study investigates a range of slope to basin floor topographic configurations with multi-scale (mm to 100 km) variability, using regionally extensive exposures from the Permian slope to basin floor deposits in the Laingsburg depocentre, Karoo Basin, South Africa. Over 400 outcrop logs, totalling 14 km in thickness, combined with a large database from earlier Stratigraphy Group studies, are used to assess the influence of dynamic seabed relief on turbidity current processes and depositional patterns across a range of scales, and their transfer into the stratigraphic record. Degradation plays a large role in shaping submarine slopes. The formation and evolution of a submarine slide complex is investigated, including time transgressive lateral margins of basal shear surfaces/zones and varyingly confined of remobilized and turbidite infill. The base of slope is a key area of gradient change. Here, the spatial and temporal variations of a channel-lobe transition zone (CLTZ) are documented, including how topographic influence on turbidity currents varies and evolves, causing CLTZ expansion/contraction and migration. In addition, how these topographically complex areas are transferred into the stratigraphic record, as single surfaces and volumes of rock, is discussed. Areas of dynamic and fixed topography have been recognised as having long-term effects, leading to the evolution of a stepped slope profile. In the Laingsburg depocentre stepped slope topography initiated before major clastic input and increased temporally, gradually outpacing sediment supply. The effects of slope orientation and gradient change on flow processes and stratigraphic architecture are presented as a range of intraslope lobe deposits and bypass dominated zones

Dopamine Cell Loss within the Nigrostriatal Pathway Due to Oxidative Stress from Chronic Methylphenidate

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder that affects 11% of children in the US alo­ne. Methylphenidate (MPH) is the most commonly prescribed drug for the treatment of ADHD. Given the fact that ADHD symptoms persist in up to 50% of patients, many children receive MPH from childhood to early adulthood. Unfortunately, most of the scientific literature focuses on the short-term consequences of MPH, even though individuals are taking MPH for many years. MPH acts by blocking dopamine (DA) transporters and norepinephrine transporters, preventing the reuptake of these catecholamines following release. Previous research has shown that long-term exposure to MPH causes dopaminergic neurons within the nigrostriatal pathway to be more sensitive to the Parkinsonian toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We hypothesize that oxidative stress caused by the spontaneous oxidation of the excess DA in the synaptic cleft is what’s rendering dopaminergic neurons within the nigrostriatal pathway to be more sensitive to MPTP. Adolescent male Swiss-Webster mice were divided into three cohorts and administered either saline (control), 1 mg/kg MPH (normal dose) or 10 mg/kg (abusive dose) via intraperitoneal (IP) injections for 12 weeks. Mice were injected twice daily, Monday through Friday, mimicking a school-week dosing schedule. After 12 weeks, all animals received a drug washout period of 7 days. Then, half of each cohort was treated with MPTP (4 x 20mg/kg, every 2 hours), while the other half was administered 4 injections of sterile saline. Seven days after MPTP or saline treatment, the mice were sacrificed, brains were removed, and the substantia nigra (SN) and striatum (STR) were collected. Oxidative stress related to increased DA levels was determined using the glutathione assay to measure glutathione (GSH) content and near-infrared fluorescence dot blots to measure free and protein-bound ortho-quinones. GSH is an important antioxidant and thus its depletion would be indicative of oxidative stress. Additionally, since DA may be oxidized to a quinone, increases in free and protein-bound ortho-quinones also indicate oxidative stress. Interestingly, we observed a significant decrease in GSH as the dose of MPH increased with both saline and MPTP samples. Furthermore, there was a significant increase in quinones as the dose of MPH increased. In conclusion, it appears that long-term exposure to MPH sensitizes dopaminergic neurons within the nigrostriatal pathway to oxidative stress, rendering them vulnerable to further insults, such as MPTP exposure. As such, these studies provide insight into the risks of long-term psychostimulant exposure

Fish mouths as engineering structures for vortical cross-step filtration

Suspension-feeding fishes such as goldfish and whale sharks retain prey without clogging their oral filters, whereas clogging is a major expense in industrial crossflow filtration of beer, dairy foods and biotechnology products. Fishes\u27 abilities to retain particles that are smaller than the pore size of the gill-raker filter, including extraction of particles despite large holes in the filter, also remain unexplained. Here we show that unexplored combinations of engineering structures (backward-facing steps forming d-type ribs on the porous surface of a cone) cause fluid dynamic phenomena distinct from current biological and industrial filter operations. This vortical cross-step filtration model prevents clogging and explains the transport of tiny concentrated particles to the oesophagus using a hydrodynamic tongue. Mass transfer caused by vortices along d-type ribs in crossflow is applicable to filter-feeding duck beak lamellae and whale baleen plates, as well as the fluid mechanics of ventilation at fish gill filaments

Estimating the effect of the 2005 change in BCG policy in England:a retrospective cohort study, 2000 to 2015

BackgroundIn 2005 in England, universal Bacillus Calmette-Guérin (BCG) vaccination of school-age children was replaced by targeted BCG vaccination of high-risk neonates.AimEstimate the impact of the 2005 change in BCG policy on tuberculosis (TB) incidence rates in England.MethodsWe conducted an observational study by combining notifications from the Enhanced Tuberculosis Surveillance system, with demographic data from the Labour Force Survey to construct retrospective cohorts relevant to both the universal and targeted vaccination between 1 January 2000 and 31 December 2010. We then estimated incidence rates over a 5-year follow-up period and used regression modelling to estimate the impact of the change in policy on TB.ResultsIn the non-United Kingdom (UK) born, we found evidence for an association between a reduction in incidence rates and the change in BCG policy (school-age incidence rate ratio (IRR): 0.74; 95% credible interval (CrI): 0.61 to 0.88 and neonatal IRR: 0.62; 95%CrI: 0.44 to 0.88). We found some evidence that the change in policy was associated with an increase in incidence rates in the UK born school-age population (IRR: 1.08; 95%CrI: 0.97 to 1.19) and weaker evidence of an association with a reduction in incidence rates in UK born neonates (IRR: 0.96; 95%CrI: 0.82 to 1.14). Overall, we found that the change in policy was associated with directly preventing 385 (95%CrI: -105 to 881) cases.ConclusionsWithdrawing universal vaccination at school age and targeting vaccination towards high-risk neonates was associated with reduced incidence of TB. This was largely driven by reductions in the non-UK born with cases increasing in the UK born

Physical modeling of vortical cross-step flow in the American paddlefish, Polyodon spathula

Vortical cross-step filtration in suspension-feeding fish has been reported recently as a novel mechanism, distinct from other biological and industrial filtration processes. Although crossflow passing over backward-facing steps generates vortices that can suspend, concentrate, and transport particles, the morphological factors affecting this vortical flow have not been identified previously. In our 3D-printed models of the oral cavity for ram suspension-feeding fish, the angle of the backward-facing step with respect to the model’s dorsal midline affected vortex parameters significantly, including rotational, tangential, and axial speed. These vortices were comparable to those quantified downstream of the backward-facing steps that were formed by the branchial arches of preserved American paddlefish in a recirculating flow tank. Our data indicate that vortices in cross-step filtration have the characteristics of forced vortices, as the flow of water inside the oral cavity provides the external torque required to sustain forced vortices. Additionally, we quantified a new variable for ram suspension feeding termed the fluid exit ratio. This is defined as the ratio of the total open pore area for water leaving the oral cavity via spaces between branchial arches that are not blocked by gill rakers, divided by the total area for water entering through the gape during ram suspension feeding. Our experiments demonstrated that the fluid exit ratio in preserved paddlefish was a significant predictor of the flow speeds that were quantified anterior of the rostrum, at the gape, directly dorsal of the first ceratobranchial, and in the forced vortex generated by the first ceratobranchial. Physical modeling of vortical cross-step filtration offers future opportunities to explore the complex interactions between structural features of the oral cavity, vortex parameters, motile particle behavior, and particle morphology that determine the suspension, concentration, and transport of particles within the oral cavity of ram suspension-feeding fish