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BACKGROUND: Routine screening chest computed tomography (CT) prior to primary cardiac surgery is advocated by some surgeons due to the purported benefits of identifying significant aortic calcification that impacts ongoing management, such as performing anaortic off-pump surgery or adjusting cannulation strategy. Additionally, axial imaging can identify incidental findings that may require concomitant or staged procedures such as ascending aortic dilatation or pulmonary lesions. The objective of this study was to quantify the impact that nonselective chest CT prior to primary cardiac surgery had on subsequent management. METHOD: A systematic review and pooled prevalence meta-analyses were performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Included studies performed non-selective chest CT prior to primary cardiac surgery. RESULTS: A total of eight studies, including 2,250 patients were included. The rate of mortality and stroke was low (1% and 2%, respectively). Calcification of the ascending aorta was identified in 15% of patients (95% confidence interval [CI] 5.0-26.0). A significant change to the surgical plan such as cannulation strategy, off-pump surgery, cancellation, or an additional procedure was required in 7% (95% CI 2.0-12.0). Clinically relevant incidental findings requiring in-patient management or follow-up were identified in 10% (95% CI 6.0-14.0). CONCLUSIONS: Nonselective CT chest prior to primary cardiac surgery identifies clinically relevant findings that result in a modification of the surgical plan in a significant population of patients to address the risk of stroke associated with aortic calcification as well as the identification of important incidental findings such as pulmonary lesions.
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BACKGROUND: Reports of adverse reactions to metal debris contributed in part to a decline in use of large-bearing metal-on-metal total hip devices. We hypothesize an optimal trunnion design may reduce risk of this failure mode in large-bearing total hip arthroplasty systems. The purpose of this study is to report mid- to long-term outcomes for a single-surgeon series of 211 total hip arthroplasties using the large-bearing Biomet Magnum metal-on-metal system. MATERIALS AND METHODS: Between December 2004 and January 2016, the primary surgeon performed 211 uncemented Magnum total hip arthroplasties in 181 patients. The average length of follow-up was 10.1 ± 3.5 years (range 8-18 years). RESULTS: Using failure of any component as the endpoint, the overall survivorship rate was 98.1% at 10 years and 97.4% at 18 years. These eight failures (3.8% of cohort) included one case of adverse wear-related failure (0.5%), two cases of acetabular ingrowth failure (0.9%), three cases of trunnion corrosion (1.4%), one failure of late infection (0.5%), and one inappropriate revision of components for trochanteric nonunion without instability (0.5%). Excluding failed cases, all components were radiographically stable with no radiolucencies. Except for the one wear failure, ion testing revealed that 97.2% of cases were within optimal whole blood metal ion levels with the remaining ion test results within acceptable levels. CONCLUSIONS: With the uncemented Magnum metal-on-metal total hip, we achieved 97.4% 18-year implant survivorship, exceeding the NICE criteria and registry benchmarks for implant survivorship. We observed a trunnion corrosion rate of 1.4% and no cases of instability. The single case of adverse wear-related failure was caused by acetabular component malposition.
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The success of the animal in coping with challenges, and in harnessing opportunities to thrive, is central to its welfare. Functional capacity describes the capacity of molecules, cells, organs, body systems, the whole animal, and its community to buffer against the impacts of environmental perturbations. This buffering capacity determines the ability of the animal to maintain or regain functions in the face of environmental perturbations, which is recognised as resilience. The accuracy of physiological regulation and the maintenance of homeostatic balance underwrite the dynamic stability of outcomes such as biorhythms, feed intake, growth, milk yield, and egg production justifying their assessment as indicators of resilience. This narrative review examines the influence of environmental enrichments, especially during developmental stages in young animals, in building functional capacity and in its subsequent expression as resilience. Experience of enriched environments can build skills and competencies across multiple functional domains including but not limited to behaviour, immunity, and metabolism thereby increasing functional capacity and facilitating resilience within the context of challenges such as husbandry practices, social change, and infection. A quantitative method for measuring the distributed property of functional capacity may improve its assessment. Methods for analysing embedded energy (emergy) in ecosystems may have utility for this goal. We suggest functional capacity provides the common thread that links environmental enrichments with an ability to express resilience and may provide a novel and useful framework for measuring and reporting resilience. We conclude that the development of functional capacity and its subsequent expression as resilience is an aspect of positive animal welfare. The emergence of resilience from system dynamics highlights a need to shift from the study of physical and mental states to the study of physical and mental dynamics to describe the positive dimension of animal welfare.
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Crianza de Animales Domésticos , Bienestar del Animal , Ambiente , Animales , Crianza de Animales Domésticos/métodos , Ganado/fisiologíaRESUMEN
Heparin is postulated to block the interaction of SARS-CoV-2 with highly glycosylated proteins which are critical for binding the angiotensin-converting enzyme 2 (ACE2), an essential mechanism for host-cell entry and viral replication. Intranasal heparin is under investigation for use as a SARS-CoV-2 preventative in the IntraNasal Heparin Trial (INHERIT, NCT05204550). Heparin directly interferes with real-time quantitative polymerase chain reaction (RT-qPCR), the gold standard for SARS-CoV-2 detection. This study aimed to investigate the magnitude of heparin interference across various clinical laboratory testing platforms, and the reversal of any interference by degradation of heparin using the heparinase I enzyme in nasopharyngeal swab (NP) samples for SARS-CoV-2 analysis by RT-qPCR. Heparin-mediated PCR interference was evident at heparin concentrations as low as 10 IU/mL across all platforms tested, with the exclusion of the Hologic Panther Aptima SARS-CoV-2 assay. Rates of false negative or invalid results increased with increasing heparin concentrations on all platforms, except the Hologic Panther Aptima and Roche Cobas LIAT. Heparinase I reversed heparin-mediated PCR inhibition across in all samples tested, except those with initial Ct values >35. Our study shows that the use of heparin-containing nasal sprays interferes with the detection of SARS-CoV-2 in NP swab samples by RT-qPCR, a phenomenon that is not well recognised in the literature. Furthermore, this study has also demonstrated that heparin-mediated PCR inhibition can be prevented through heparinase I treatment, demonstrating restoration of clinically significant results with Ct values <35.
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COVID-19 , Liasa de Heparina , Heparina , SARS-CoV-2 , Liasa de Heparina/metabolismo , Humanos , SARS-CoV-2/genética , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/aislamiento & purificación , COVID-19/diagnóstico , COVID-19/virología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Prueba de Ácido Nucleico para COVID-19/métodos , Nasofaringe/virología , Reacciones Falso NegativasRESUMEN
Molecular oxygen (O2) concentration is measured by employing nanosecond laser-induced plasmas (ns-LIP) over a broad temperature spectrum ranging from 300â K to 1000â K, in the presence of an additional oxygen-containing molecule, CO2. Typically, emission spectra emanating from ns-LIP are devoid of molecular information, as the ns-LIP causes the dissociation of molecular species within the plasma. However, atomic oxygen absorption lines that momentarily appear at 777â nm in the broadband emission from the early-stage plasma are determined to be highly sensitive to the O2 mole fraction but negligibly affected by the CO2 mole fraction. The atomic O absorbing the plasma emission originates from the O2 adjacent to the plasma: robust UV radiation from the early-stage plasma selectively dissociates adjacent O2, exhibiting a relatively low photodissociation threshold, thus generating the specific meta-stable oxygen capable of absorbing photons at 777â nm. A theoretical model is introduced, explicating the formation of the meta-stable O atom from adjacent O2. To sustain the UV radiation from the plasma under high-temperature and low-density ambient conditions, a preceding breakdown is triggered by a split laser pulse (532â nm). This breakdown acts as a precursor, seeding electrons to intensify the inverse-Bremsstrahlung photon absorption of the subsequent laser pulse (1064â nm). Techniques such as proper orthogonal decomposition (POD) and support vector regression (SVR) are employed to precisely evaluate the O2 mole fraction (<1% uncertainty), by analyzing the short-lived (<10â ns) O2-indicator depicted in the early-stage plasma.
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International recommendations encourage liberal administration of oxygen to patients having surgery under general anaesthesia, ostensibly to reduce surgical site infection. However, the optimal oxygen regimen to minimise postoperative complications and enhance recovery from surgery remains uncertain. The hospital operating theatre randomised oxygen (HOT-ROX) trial is a multicentre, patient- and assessor-blinded, parallel-group, randomised clinical trial designed to assess the effect of a restricted, standard care, or liberal peri-operative oxygen therapy regimen on days alive and at home after surgery in adults undergoing prolonged non-cardiac surgery under general anaesthesia. Here, we report the findings of the internal vanguard feasibility phase of the trial undertaken in four large metropolitan hospitals in Australia and New Zealand that included the first 210 patients of a planned overall 2640 trial sample, with eight pre-specified endpoints evaluating protocol implementation and safety. We screened a total of 956 participants between 1 September 2019 and 26 January 2021, with data from 210 participants included in the analysis. Median (IQR [range]) time-weighted average intra-operative Fi O2 was 0.30 (0.26-0.35 [0.20-0.59]) and 0.47 (0.44-0.51 [0.37-0.68]) for restricted and standard care, respectively (mean difference (95%CI) 0.17 (0.14-0.20), p < 0.001). Median time-weighted average intra-operative Fi O2 was 0.83 (0.80-0.85 [0.70-0.91]) for liberal oxygen therapy (mean difference (95%CI) compared with standard care 0.36 (0.33-0.39), p < 0.001). All feasibility endpoints were met. There were no significant patient adverse events. These data support the feasibility of proceeding with the HOT-ROX trial without major protocol modifications.
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Terapia por Inhalación de Oxígeno , Oxígeno , Adulto , Humanos , Estudios de Factibilidad , Terapia por Inhalación de Oxígeno/métodos , Australia , Nueva ZelandaRESUMEN
In recent years, significant progress has been made in laser wakefield acceleration (LWFA), both regarding the increase in electron energy, charge and stability as well as the reduction of bandwidth of electron bunches. Simultaneous optimization of these parameters is, however, still the subject of an ongoing effort in the community to reach sufficient beam quality for next generation's compact accelerators. In this report, we show the design of slit-shaped gas nozzles providing centimeter-long supersonic gas jets that can be used as targets for the acceleration of electrons to the GeV regime. In LWFA experiments at the Centre for Advanced Laser Applications, we show that electron bunches are accelerated to [Formula: see text] using these nozzles. The electron bunches were injected into the laser wakefield via a laser-machined density down-ramp using hydrodynamic optical-field-ionization and subsequent plasma expansion on a ns-timescale. This injection method provides highly controllable quasi-monoenergetic electron beams with high charge around [Formula: see text], low divergence of [Formula: see text], and a relatively small energy spread of around [Formula: see text] at [Formula: see text]. In contrast to capillaries and gas cells, the scheme allows full plasma access for injection, probing or guiding in order to further improve the energy and quality of LWFA beams.
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Spinal cord stimulators (SCS) and peripheral nerve stimulators (PNS) are increasingly used in the treatment of chronic pain, allowing more patients to resume working and return to activities. Military service members face environmental and occupational hazards that expose them to mechanical and electromagnetic forces, both clinical and industrial, that could potentially alter their function. While there are reports of individual hazards, the risk appears to be nominal based on the large number of devices in use and the limited reported complications with these devices. Since a variety of hazards encountered by military patients have the potential to alter SCS and PNS devices, a brief discussion of each patient's specific exposures and related hazards should occur prior to placement. Overall, these devices have demonstrated safety in hazardous areas and few military patients have contraindications for placement based on these factors alone.
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The emergence and explosive spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 highlighted the need to rapidly develop curated biobanks to inform the etiology, diagnosis, and treatment options for global outbreaks of communicable diseases. Recently, we undertook efforts to develop a repository of biospecimens from individuals aged 12 and older who were to be vaccinated against coronavirus disease 19 (COVID-19) with vaccines developed with support from the United States Government. We planned to establish 40 or more clinical study sites in at least six countries to collect biospecimens from 1,000 individuals, 75% of whom were to be SARS-CoV-2 naive at the time of enrollment. Specimens would be used to (i) ensure quality control of future diagnostic tests, (ii) understand immune responses to multiple COVID-19 vaccines, and (iii) provide reference reagents for the development of new drugs, biologics, and vaccines. Biospecimens included serum, plasma, whole blood, and nasal secretions. Large-volume collections of peripheral blood mononuclear cells (PBMCs) and defibrinated plasma were also planned for a subset of subjects. Participant sampling was planned at intervals prior to and following vaccination over a 1-year period. Here, we describe the selection of clinical sites for specimen collection and processing, standard operating procedure (SOP) development, design of a training program for tracking specimen quality, and specimen transport to a repository for interim storage. This approach allowed us to enroll our first participants within 21 weeks from the study's initiation. Lessons learned from this experience should benefit the development of biobanks in response to future global epidemics. IMPORTANCE The ability to rapidly create a biobank of high-quality specimens in response to emergent infectious diseases is critical to allow for the development of prevention and treatment, as well as to effectively monitor the spread of the disease. In this paper, we report on a novel approach to getting global clinical sites up and running within a short time frame and to monitor the quality of specimens collected to ensure their value in future research efforts. Our results have important implications for the monitoring of the quality of biospecimens collected and to design effective interventions to address shortcomings, where needed.
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COVID-19 , Humanos , COVID-19/prevención & control , SARS-CoV-2 , Vacunas contra la COVID-19 , Leucocitos Mononucleares , Manejo de Especímenes/métodosRESUMEN
INTRODUCTION: Acute Type A Aortic Dissection (ATAAD) is a cardiothoracic emergency that requires urgent intervention. Elderly status, particularly age over 80, is an independent risk factor for mortality and morbidity. The mid-term outcomes of this age group are also unknown. This systematic review and meta-analysis of observational studies was therefore performed to analyse short- and mid-term mortality and morbidity in octogenarians following surgery for ATAAD. METHODS: A systematic review was conducted for studies published since January 2000. The primary endpoint was short-term mortality, either reported as 30-day mortality or in-hospital mortality and medium-term (five year) survival. Secondary endpoints were rates of postoperative complications, namely stroke, acute renal failure (ARF), re-exploration and intensive care unit (ICU) length of stay (LOS). RESULTS: A total of 16 retrospective studies, with a total of 16, 641 patients were included in the systematic review and meta-analysis. Pooled analysis demonstrated that octogenarian cohorts are at significantly higher risk of short-term mortality than non-octogenarians (OR 1.93; 95% CI 1.33-2.81; P < 0.001). Actuarial survival was significantly lower in the octogenarian cohort, with a five-year survival in the octogenarian cohort of 54% compared to 76% in the non-octogenarian cohort (P < 0.001). There were no significant differences between the cohorts in terms of secondary outcomes: stroke, ARF, re-exploration or ICU LOS. CONCLUSION: Octogenarians are twice as likely to die in the short-term following surgery for ATAAD and demonstrate a significantly lower five-year actuarial survival. Patients and family members should be well informed of the risks of surgery and suitable octogenarians selected for surgery.
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Disección Aórtica , Accidente Cerebrovascular , Factores de Edad , Anciano , Anciano de 80 o más Años , Disección Aórtica/cirugía , Humanos , Estudios Observacionales como Asunto , Complicaciones Posoperatorias , Estudios Retrospectivos , Factores de Riesgo , Factores de Tiempo , Resultado del TratamientoRESUMEN
Using sound velocity and attenuation measurements in high magnetic fields, we identify a new transition in the vortex lattice state of La_{2-x}Sr_{x}CuO_{4}. The transition, observed in magnetic fields exceeding 35 T and temperatures far below zero field T_{c}, is detected in the compression modulus of the vortex lattice, at a doping level of x=p=0.17. Our theoretical analysis based on Eilenberger's theory of the vortex lattice shows that the transition corresponds to the long-sought 45° rotation of the square vortex lattice, predicted to occur in d-wave superconductors near a van Hove singularity.
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The deep biosphere is the largest microbial habitat on Earth and features abundant bacterial endospores. Whereas dormancy and survival at theoretical energy minima are hallmarks of microbial physiology in the subsurface, ecological processes such as dispersal and selection in the deep biosphere remain poorly understood. We investigated the biogeography of dispersing bacteria in the deep sea where upward hydrocarbon seepage was confirmed by acoustic imagery and geochemistry. Thermophilic endospores in the permanently cold seabed correlated with underlying seep conduits reveal geofluid-facilitated cell migration pathways originating in deep petroleum-bearing sediments. Endospore genomes highlight adaptations to life in anoxic petroleum systems and bear close resemblance to oil reservoir microbiomes globally. Upon transport out of the subsurface, viable thermophilic endospores reenter the geosphere by sediment burial, enabling germination and environmental selection at depth where new petroleum systems establish. This microbial dispersal loop circulates living biomass in and out of the deep biosphere.
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INTRODUCTION: Atrial fibrillation (AF) is the most common arrhythmia. Hybrid convergent ablation (HCA) is an emerging procedure for treating longstanding AF with promising results. HCA consists of a subxiphoid, surgical ablation followed by completion endocardial ablation. This meta-analysis of randomized control trials (RCT's) and propensity score-matched studies aims to examine the efficacy and safety of HCA compared to endocardial catheter ablation (ECA) alone on patients with AF. METHODS: This review was written in accordance with preferred reporting items for systematic reviews and meta-analyses recommendations and guidance. The primary outcome for the analysis was freedom from AF (FFAF) at final follow up. Secondary outcomes were mortality and significant complications such as tamponade, sternotomy, esophageal injury, atrio-esophageal fistulae post procedurally. RESULTS: Four studies where included, with a total of 233 patients undergoing HCA and 189 patients undergoing ECA only. Pooled analysis demonstrated that HCA cohorts had significantly higher rates of FFAF than ECA cohorts, with an OR of 2.78 (95% CI 1.82-4.24, P < 0.01, I2 = 0). Major post-operative complications were observed in significantly more patients in the HCA group, with an OR of 5.14 (95% CI 1.70-15.54, P < 0.01). There was only one death reported in the HCA cohorts, with no deaths in the ECA cohort. CONCLUSION: HCA is associated with a significantly higher FFAF than ECA, however, it is associated with increased post-procedural complications. There was only one death in the HCA cohort. Large RCT's comparing the HCA and ECA techniques may further validate these results.
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Técnicas de Ablación , Fibrilación Atrial , Ablación por Catéter , Fibrilación Atrial/cirugía , Ablación por Catéter/métodos , Endocardio/cirugía , Humanos , Resultado del TratamientoRESUMEN
Fascin is an important regulator of F-actin bundling leading to enhanced filopodia assembly. Fascin is also overexpressed in most solid tumours where it supports invasion through control of F-actin structures at the periphery and nuclear envelope. Recently, fascin has been identified in the nucleus of a broad range of cell types but the contributions of nuclear fascin to cancer cell behaviour remain unknown. Here, we demonstrate that fascin bundles F-actin within the nucleus to support chromatin organisation and efficient DDR. Fascin associates directly with phosphorylated Histone H3 leading to regulated levels of nuclear fascin to support these phenotypes. Forcing nuclear fascin accumulation through the expression of nuclear-targeted fascin-specific nanobodies or inhibition of Histone H3 kinases results in enhanced and sustained nuclear F-actin bundling leading to reduced invasion, viability, and nuclear fascin-specific/driven apoptosis. These findings represent an additional important route through which fascin can support tumourigenesis and provide insight into potential pathways for targeted fascin-dependent cancer cell killing.
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Actinas , Neoplasias , Actinas/metabolismo , Proteínas Portadoras , Supervivencia Celular , Histonas , Humanos , Proteínas de Microfilamentos , Neoplasias/patologíaRESUMEN
BACKGROUND: Provision of virtual health care (VHC) home monitoring for patients who are experiencing mild to moderate COVID-19 illness is emerging as a central strategy for reducing pressure on acute health systems. Understanding the enablers and challenges in implementation and delivery of these programs is important for future implementation and re-design. The aim of this study was to explore the perspectives of staff involved with the implementation and delivery, and the experience of patients managed by, a VHC monitoring service in Melbourne, Australia during the COVID-19 pandemic. METHODS: A descriptive qualitative approach informed by naturalist inquiry was used. Staff interviews were analysed using the Consolidated Framework for Implementation Research (CFIR). Patient experience was captured using a survey and descriptive statistics were used to describe categorical responses while content analysis was used to analyse free text responses as they related to the CFIR. Finally, data from the interviews and patient experience were triangulated to see if patient experience validated data from staff interviews. RESULTS: All 15 staff were interviewed, and 271 patients were surveyed (42%). A total of four final overarching themes emerged: service implementation enablers, service delivery benefits for patients, fragmentation of care, and workforce strengths. 19 subthemes aligned with 18 CFIR constructs from staff and patient data. CONCLUSION: Rapid implementation was enabled through shared resources, dividing implementation tasks between senior personnel, engaging furloughed healthcare staff in design and delivery, and having a flexible approach that allowed for ongoing improvements. Benefits for patients included early identification of COVID-19 deterioration, as well as provision of accurate and trustworthy information to isolate safely at home. The main challenges were the multiple agencies involved in patient monitoring, which may be addressed in the future by attributing responsibility for monitoring to a single agency.
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COVID-19 , Australia , COVID-19/epidemiología , Atención a la Salud , Humanos , Pandemias , Evaluación del Resultado de la Atención al Paciente , Investigación CualitativaRESUMEN
Background: Improvements in revascularisation, including pharmacological, catheter-based and surgical, have resulted in improved outcomes for patients with acute myocardial infarction (AMI), leading to decreased frequency of mechanical complications. Improvements in both techniques and technology have permitted select patients to be managed with a purely percutaneous, transcatheter strategy. Through systematic review, this study aims to synthesise the collective experience of percutaneous treatment of the mechanical complications of ischaemic heart disease. Methods: The search strategy queried the electronic databases PubMed, Embase and the Cochrane Central Register of Controlled Trials, from 1 January 2000 to 31 December 2020. Studies highlighting the outcomes of patients receiving percutaneous treatment of post-myocardial infarction papillary muscle rupture (PMR), ventricular septal defect (VSD), left ventricular free wall rupture (FWR) and pseudoaneurysm (PA) were included. A qualitative review of studies was conducted for PMR, FWR and PA. A quantitative analysis was conducted for VSD. Results: Fifteen studies were included in the qualitative synthesis of the percutaneous management of PMR, 4 were included in the qualitative analysis of the percutaneous management of left ventricular FWR, 7 studies defined the outcomes of the percutaneous management of PA and 25 were included in the quantitative meta-analysis of the primary percutaneous management of post-MI VSD. For VSD, there were 43 failed procedures in 314 patients. The proportion of failed procedures was 15.9% and there were 174 deaths in 428 patients. 37.5% of patients experienced early mortality. Conclusions: Although surgical techniques remain the gold standard, we have shown that percutaneous management may be a viable option in certain cases.
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Nanosecond (ns) laser pulses are modulated by seeding electrons on the laser beam path. The seed-electrons are from auxiliary ns-laser-induced breakdown (ALIB), and the ALIB is induced by a focused 1064-nm pulse, which is split after the frequency-doubling that generates the 532-nm pulse; therefore, the 532-nm and 1064-nm pulses are synchronized. The slowly converging (focal length = 500 mm) 532-nm pulse is re-directed to transmit through the region in where the ALIB-generated electrons reside. The seed-electrons from the ALIB then absorb the 532-nm photons via the inverse-Bremsstrahlung photon absorption (IBPA) process. The number density of the seed-electrons on the 532-nm beam path (ne,ALIB) is controlled by varying 1) the 532-nm pulse arrival time at the ALIB region (ΔPAT) after the 1064-nm pulse triggers the ALIB and 2) the location of the 532-nm beam relative to the core of the ALIB; the electron number density in ALIB is highly non-uniform and evolves in time. Electron-seeded laser-induced breakdown (ESLIB) occurs when ne,ALIB is sufficiently high. The 532-nm beam convergence (controlled by the focusing lens) is adjusted so that the breakdown does not occur without the electron seeding. The ESLIB immediately stops the transmission of the trailing edge of the laser pulse acting as a fast shutter, and ne,ALIB above a threshold can cut the pulse leading edge to modulate the 532-nm laser pulse.
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ABSTRACT: In this paper, an experimental study of the non-reacting turbulent flow field characteristics of a piloted premixed Bunsen burner designed for operational at elevated pressure conditions is presented. The generated turbulent flow fields were experimentally investigated at atmospheric and elevated pressure by means of high-speed particle image velocimetry (PIV). The in-nozzle flow through the burner was computed using large-eddy simulation (LES), and the turbulent flow field predicted at the burner exit was compared against the experimental results. The findings show that the burner yields a reasonably homogeneous, nearly isotropic turbulence at the nozzle exit with highly reproducible boundary conditions that can be well predicted by numerical simulations. Similar levels of turbulence intensities and turbulent length scales were obtained at varied pressures and bulk velocities with turbulent Reynolds numbers up to 5300. This work demonstrates the burner's potential for the study of premixed flames subject to intermediate and extreme turbulence at the elevated pressure conditions found in gas turbine combustors.
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BACKGROUND: The management of aortic valve disease is becoming increasingly complicated with the evolution of treatment options available to cardiac surgeons and cardiologist. Pulmonary autograft replacement of the aortic valve, commonly known as the Ross procedure, involves excision of the pulmonary valve from the right ventricular outflow tract and implantation in the aortic position. This systematic review aims to evaluate the long-term outcomes, following the Ross procedure. METHODS: An electronic search strategy queried five online medical referencing databases from inception to 21 August 2020. All studies detailing the long-term outcomes of adults undergoing the Ross procedure were included. A random effects model was used to determine pooled continuous data. Enhanced secondary survival analysis was performed on reconstructed individual patient data. RESULTS: Twenty-three studies were included in the qualitative synthesis, including a total of 6,278 patients with a mean follow-up duration of 6.0±2.8 years. Long-term survival was 95.6%, 91.8%, 86.3% and 80.5% at five, ten, fifteen and twenty years, respectively. Freedom from autograft reoperation was 95.7%, 91.2%, 84.9% and 76.1% at five, ten, fifteen and twenty years, respectively. CONCLUSIONS: When performed in experienced centres and for appropriately selected patients, the Ross procedure represents a durable replacement of the aortic valve with excellent long-term survival.