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An experimental investigation using stereo particle image velocimetry (SPIV) was performed to study the vortex dynamics of an aspect ratio 13 rectangular orifice synthetic jet issuing into quiescent fluid. Data were obtained on the orifice centreline planes for four Reynolds numbers and five Strouhal numbers, ranging from 298 to 731 and 0.039 to 0.100, respectively. At one condition, SPIV data obtained on parallel planes distributed across the width of the jet were used to reconstruct the three-dimensional, three-component velocity field. The results reveal that the axis switching deformations of the non-circular vortex rings give rise to several types of secondary structures. Before the primary vortex ring completed its first axis switch, the anti-parallel sides of the ring collided, resulting in vorticity reconnection. Consequently, the elongated vortex ring bifurcated into two circular vortex rings which propagated off along independent paths. The development and structure of vortex ring bifurcation in addition to the bifurcation's effect on the jet shape, momentum and entrainment are presented. The bifurcation process captured in the synthetic jet experiment is similar in many ways to computational simulations of isolated vortex rings. Despite these similarities and the fact that vortex ring bifurcation was detected for all conditions tested, it is shown that the bifurcation process is sensitive to the unique conditions in synthetic jets, specifically the proximity of other vortex rings as indicated by the Strouhal number. Finally, the results at different jet conditions are discussed in relation to prior studies of synthetic jets.
A control volume based analytical method for calculating the efficiency
of flapping foil power generators was developed for single and tandem foil configurations. Ignoring unsteady effects and non-uniform pressures resulted in theoretical limits identical to the Betz (
for a single turbine) and Newman (
for tandem turbines) limits. Inclusion of unsteady flow and non-uniform pressure distributions produced theoretical efficiency maxima in excess of these limits. Simulation of single and tandem foil cases to determine the magnitude of these effects showed that the Betz limit would not be exceeded by a single foil system in practice, but that it is conceivable that a tandem foil system could exceed the Newman limit due to the strong unsteady vortex wake of the upstream turbine entraining additional energy into the path of the downstream turbine and maintaining pressures in the wake below ambient.
Many exact coherent states (ECS) arising in wall-bounded shear flows have an asymptotic structure at extreme Reynolds number
in which the effective Reynolds number governing the streak and roll dynamics is
. Consequently, these viscous ECS are not suitable candidates for quasi-coherent structures away from the wall that necessarily are inviscid in the mean. Specifically, viscous ECS cannot account for the singular nature of the inertial domain, where the flow self-organizes into uniform momentum zones (UMZs) separated by internal shear layers and the instantaneous streamwise velocity develops a staircase-like profile. In this investigation, a large-
asymptotic analysis is performed to explore the potential for a three-dimensional, short streamwise- and spanwise-wavelength instability of the embedded shear layers to sustain a spatially distributed array of much larger-scale, effectively inviscid streamwise roll motions. In contrast to other self-sustaining process theories, the rolls are sufficiently strong to differentially homogenize the background shear flow, thereby providing a mechanistic explanation for the formation and maintenance of UMZs and interlaced shear layers that respects the leading-order balance structure of the mean dynamics.
Molecular weight (Mw) effects in poly(vinylidene fluoride) (PVDF) influence both processability and combustion behavior in energetic Al–PVDF filaments. Results show decreased viscosity in unloaded and fuel-lean (i.e., 15 wt% Al) filaments. In highly loaded filaments (i.e., 30 wt% Al), reduced viscosity is minimal due to higher electrostatic interaction between Al particles and low Mw chains as confirmed by Fourier-transform infrared spectroscopy. Thermal and combustion analysis further corroborates this story as exothermic activity decreases in PVDF with smaller Mw chains. Differential scanning calorimetry and Thermogravimetric analysis show reduced reaction enthalpy and lower char yield in low Mw PVDF. Enthalpy reduction trends continued in nonequilibrium burn rate studies, which confirm that burn rate decreases in the presence of low Mw PVDF. Furthermore, powder X-ray patterns of post-burn products suggest that low Mw PVDF decomposition creates a diffusion barrier near the Al particle surface resulting in negligible AlF3 formation in fuel-rich filaments.
This article addresses recent advances in liquid phase transmission electron microscopy (LPTEM) for studying nanoscale synthetic processes of carbon-based materials that are independent of the electron beam—those driven by nonradiolytic chemical or thermal reactions. In particular, we focus on chemical/physical formations and the assembly of nanostructures composed of organic monomers/polymers, peptides/DNA, and biominerals. The synthesis of carbon-based nanomaterials generally only occurs at specific conditions, which cannot be mimicked by aqueous solution radiolysis. Carbon-based structures themselves are also acutely sensitive to the damaging effects of the irradiating beam, which make studying their synthesis using LPTEM a unique challenge that is possible when beam effects can be quantified and mitigated. With new direct sensing, high frame-rate cameras, and advances in liquid cell holder designs, combined with a growing understanding of irradiation effects and proper experimental controls, microscopists have been able to make strides in observing traditionally problematic carbon-based materials under conditions where synthesis can be controlled, and imaged free from beam effects, or with beam effects quantified and accounted for. These materials systems and LPTEM experimental techniques are discussed, focusing on nonradiolytic chemical and physical transformations relevant to materials synthesis.
Healthcare workers (HCWs) have a theoretically increased risk of contracting severe acute respiratory coronavirus virus 2 (SARS-CoV-2) given their occupational exposure. We tested 2,167 HCWs in a London Acute Integrated Care Organisation for antibodies to SARS-CoV-2 in May and June 2020 to evaluate seroprevalence. We found a seropositivity rate of 31.6% among HCWs.
For many us who have studied, researched, written, and taught about the influenza pandemic of 1918–19, the current period of the global viral pandemic is eerily and unpleasantly familiar. Today, the rapid global spread of a virus has prompted policies calling for widespread closures, social distancing, constant handwashing, and public mask wearing in additional to other non-pharmaceutical interventions (NPIs). We have also seen pushback and resistance to these directives as well as substantial mismanagement of resources and a flood of misinformation. Much health policy has been inconsistently set at the local rather than federal level. These responses to our current pandemic closely mirror those to the pandemic 102 years ago.
OBJECTIVES/GOALS: Young women (18 – 45 years of age) with breast cancer have complex medical and psychosocial needs. Educational materials are often used as tools in patient-centered communication. However, these materials disseminate complex health information in print-heavy formats and can be difficult to understand for women with varying health literacy levels. METHODS/STUDY POPULATION: In the first phase of this study, the principal investigator (PI) will recruit 40 diverse women to participate in four focus groups (FG) to explore the perceived usefulness of the most frequently used cancer educational materials. The PI will also obtain demographics and heath literacy levels of the FG participants using the Newest Vital Sign. In the second phase, the PI will assess the literacy demands of the ten most frequently used cancer educational print materials and five most frequently used websites described by the FG participants. The perceptions of the usefulness of materials and the literacy demands will then be used to appraise the effectiveness of materials within patient-centered cancer communication. RESULTS/ANTICIPATED RESULTS: Results from this study will provide a patient-centered blueprint that will be used to design more effective educational materials that treatment centers can incorporate into their patient-centered cancer communication process. The next step of this research will be to determine providers’ perceptions of cancer education materials used to exchange information within the patient-centered communication process. This will complement the patient findings and inform the development of the provider aspect of a communication intervention centered on designing educational materials for women with various health literacy levels within the patient-centered cancer communication process. DISCUSSION/SIGNIFICANCE OF IMPACT: Detecting the usefulness of cancer educational materials, as perceived by young women with breast cancer, is foundational to developing communication interventions that improve cancer outcomes. This study will identify how materials can be improved in the critical informational-exchange component of the patient-communication process.
Weed management is an important issue for nursery crop and Christmas tree producers, as well as for those maintaining turfgrass or ornamental species in landscape plantings. PRE and POST herbicides are important weed management tools for these industries. Reports of herbicide-resistant weeds increased from fewer than 100 cases in 1985 to nearly 500 cases globally in 2019, including ones found in turfgrass or ornamental systems. The evolution, persistence, and management of herbicide-resistant weeds are an ongoing educational process. We must keep our stakeholders aware of improved weed control technology and provide them information on resistant weeds. A symposium at the 2019 Weed Science Society of America meeting was conducted with presentations and discussions by invited speakers in relation to current research and potential management strategies for resistant weeds in turfgrass, landscape ornamental, and nursery crops. To prepare for the symposium, a survey was prepared for nursery producers and landscapers on the issues of herbicide-resistant weeds and offsite movement of herbicides used to control herbicide-resistant weeds. Overall, most respondents felt herbicide-resistant weeds are a serious problem and most had personally observed herbicide resistance on properties they maintain. Resistance to glyphosate was the herbicide cited by most respondents, followed by resistance to triazine herbicides. Most felt their weed-control costs had increased because of resistant weeds. Approximately 20% of respondents had their operation affected by drift of herbicides from nearby farm fields, with most reporting no damage from spray or vapor drift, but a few reported greater than 50% of the crop damaged.
Why patients with psychosis use cannabis remains debated. The self-medication hypothesis has received some support but other evidence points towards an alleviation of dysphoria model. This study investigated the reasons for cannabis use in first-episode psychosis (FEP) and whether strength in their endorsement changed over time.
FEP inpatients and outpatients at the South London and Maudsley, Oxleas and Sussex NHS Trusts UK, who used cannabis, rated their motives at baseline (n = 69), 3 months (n = 29) and 12 months (n = 36). A random intercept model was used to test the change in strength of endorsement over the 12 months. Paired-sample t-tests assessed the differences in mean scores between the five subscales on the Reasons for Use Scale (enhancement, social motive, coping with unpleasant affect, conformity and acceptance and relief of positive symptoms and side effects), at each time-point.
Time had a significant effect on scores when controlling for reason; average scores on each subscale were higher at baseline than at 3 months and 12 months. At each time-point, patients endorsed ‘enhancement’ followed by ‘coping with unpleasant affect’ and ‘social motive’ more highly for their cannabis use than any other reason. ‘Conformity and acceptance’ followed closely. ‘Relief of positive symptoms and side effects’ was the least endorsed motive.
Patients endorsed their reasons for use at 3 months and 12 months less strongly than at baseline. Little support for the self-medication or alleviation of dysphoria models was found. Rather, patients rated ‘enhancement’ most highly for their cannabis use.
We evaluated a cohort of 35 children diagnosed with long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy, or arrhythmogenic right ventricular cardiomyopathy with regard to physical and psychosocial well-being.
Material and Methods:
Patients wore an accelerometer to record their time involved in moderate- to vigorous-intensity physical activity and completed the Pediatric Quality of Life Inventory and the Pediatric Cardiac Quality of Life Inventory. Parents were also asked to describe if their child had changed their physical activity because of their diagnosis and how difficult and upsetting it was for the child to adapt to the physical activity recommendations.
Patients were involved in less moderate- to vigorous-intensity physical activity per day (35 min/day versus 55 min/day) and had lower Pediatric Quality of Life Inventory total health scores (79 versus 84) compared to normative data. Overall, 51% of the cohort modified their physical activity in some way because of their diagnosis and changing physical activity was associated with lower Pediatric Quality of Life Inventory and Pediatric Cardiac Quality of Life Inventory scores.
Our cohort was involved in less moderate- to vigorous-intensity physical activity and had lower Pediatric Quality of Life Inventory total health scores compared to normative paediatric data. Modifying one’s physical activity was associated with worse health-related quality of life scores, highlighting a vulnerable sub-group of children. These findings are useful for families and healthcare professionals caring for children who are adjusting to a new cardiac diagnosis of an inherited arrhythmia or cardiomyopathy.
Intravenous tissue-type plasminogen activator (IVtPA) is a proven treatment for acute ischemic stroke; however, diabetes mellitus (DM) and previous cerebral infarction (PCI) were considered relative contraindications for thrombolysis within the 3–4.5 h period.
The study aimed to determine the safety and efficacy of IVtPA among diabetic patients with PCI presenting with acute ischemic stroke.
Studies which evaluated the outcome of IVtPA in terms of symptomatic intracerebral hemorrhage (sICH), functional outcome in modified Rankin scale, and death among diabetic patients with PCI presenting with acute ischemic stroke within the 3–4.5 h period were systematically searched until July 2019. Screening and eligibility criteria were applied. Risk of bias was evaluated using the Newcastle–Ottawa Scale. Odds ratios (ORs) with 95% confidence interval (CI) were used to compare measures of treatment effect. Mantel–Haenszel method and random-effects model were also employed.
Four registry-based studies with a total of 44,572 patients were included for quantitative synthesis. Giving IVtPA among DM+/PCI+ patients did not result in significantly increased rate of sICH (OR, 1.09; 95% CI, 0.88, 1.36) compared to No DM+/PCI+ patients. However, there was significantly higher mortality (OR, 1.81; 95% CI, 1.60, 2.06) in the DM+/PCI+ group. Conversely, among those who survived, the DM+/PCI+ patients were more functionally independent at 3 months (OR, 0.76; 95% CI, 0.61, 0.94).
Limited evidence suggests that thrombolysis in DM+/PCI+ patients does not result in significantly higher incidence of sICH and may improve functional independence. However, the significantly higher mortality in this group warrants an assessment of the individualized risk–benefit ratio in the use of IVtPA.
The present article contributes to understanding of the Zimbabwe political institution of the southern portion of the Zambesi Valley based on the conceptualization of its population, between the sixteenth and nineteenth centuries. We reconstruct the local perceptions of this institution by detecting information provided by local persons as recounted in Portuguese ethnographic documents. The original information underwent different types and degrees of translation and editing to reach the forms recorded in these documents. We present a critical process of recovering local voices, ideologies, and conceptualizations from written literal translations of excerpts of oral statements that can serve as a valuable methodological tool in expanding our understanding of the history of early African politics.
European data on health-related quality of life (HRQoL) in adults with attention deficit/hyperactivity disorder (ADHD) in the general population is sparse.
Aims and objectives
To report HRQoL in UK adults with ADHD.
UK residents aged 18–55 years with a diagnosis of adult ADHD completed an online, cross-sectional survey including questions on disease history, the EuroQol Five Dimensions questionnaire with five-levels (EQ-5D-5L) and the Work productivity and activity impairment questionnaire: general health (WPAI:GH). ADHD symptom severity was assessed by telephone using ADHD rating scale version IV with adult prompts (ADHD-RS-IV).
The survey was completed by 233 participants (65.2% women; 77.3% white British), mean age 32.6 years (standard deviation [SD] 9.5), mean ADHD-RS-IV total score 43.46 (SD 7.88). Their mean EQ-5D-5L utility score of 0.74 (SD 0.21) was lower than the UK population norm of 0.86 (SD 0.23). WPAI:GH scores indicated that health problems resulted in impairments of 32.04% in work productivity and 45.79% in regular daily activities. Regression analyses adjusting for gender, age and comorbidities demonstrated associations between EQ-5D-5L utility scores and gender (men had lower scores, P < 0.001), work impairment due to health problems (increasing impairment was associated with lower scores, P = 0.005) and age (for each additional year of age, scores decreased by 0.007, P = 0.010).
These results highlight the impact on health utility, work productivity and regular daily activities, and add to the description of the disease burden of adult ADHD in the UK.
This study was funded by Shire Development LLC.
Disclosure of interest
Kings College London research support account for Asherson received honoraria for consultancy to Shire, Eli-Lilly and Novartis educational/research awards from Shire, Lilly, Novartis, Vifor Pharma, GW Pharma and QbTech speaker at sponsored events for Shire, Lilly and Novartis.
The Pediatric Heart Network Normal Echocardiogram Database Study had unanticipated challenges. We sought to describe these challenges and lessons learned to improve the design of future studies.
Challenges were divided into three categories: enrolment, echocardiographic imaging, and protocol violations. Memoranda, Core Lab reports, and adjudication logs were reviewed. A centre-level questionnaire provided information regarding local processes for data collection. Descriptive statistics were used, and chi-square tests determined differences in imaging quality.
For the 19 participating centres, challenges with enrolment included variations in Institutional Review Board definitions of “retrospective” eligibility, overestimation of non-White participants, centre categorisation of Hispanic participants that differed from National Institutes of Health definitions, and exclusion of potential participants due to missing demographic data. Institutional Review Board amendments resolved many of these challenges. There was an unanticipated burden imposed on centres due to high numbers of echocardiograms that were reviewed but failed to meet submission criteria. Additionally, image transfer software malfunctions delayed Core Lab image review and feedback. Between the early and late study periods, the proportion of unacceptable echocardiograms submitted to the Core Lab decreased (14 versus 7%, p < 0.01). Most protocol violations were from eligibility violations and inadvertent protected health information disclosure (overall 2.5%). Adjudication committee reviews led to protocol changes.
Numerous challenges encountered during the Normal Echocardiogram Database Study prolonged study enrolment. The retrospective design and flaws in image transfer software were key impediments to study completion and should be considered when designing future studies collecting echocardiographic images as a primary outcome.
Contact guidance is vital to many physiological processes, yet is still poorly understood. This is partly due to the variability of experimental platforms, making comparisons difficult. To combat this, a multiplexed approach was used to fabricate topographical cues on single quartz coverslips for high-throughput screening. Furthermore, this method offers control of surface roughness and protein adsorption characterization, two critical aspects to the in vitro environment often overlooked in contact guidance platforms. The quartz surface can be regenerated, is compatible with versatile microscopy modes, and can scale up for manufacturing offering a novel platform that could serve as a potential standard assay.