355 research outputs found
Is High Flow Nasal Oxygenation a Game Changer in Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: A pilot study
Objectives: A pilot observational study was done to compare High Flow Nasal Oxygen (HFNO) and supraglottic airway device (SAD) technique in patients undergoing endobronchial ultrasound (EBUS) and transbronchial needle aspiration procedures (TBNA) with an objective to evaluate the efficacy of HFNO in oncological patients. Methods: The study was conducted in a tertiary cancer center in Muscat, Sultanate of Oman from May 2022 to March 2023. Consecutive patients undergoing EBUS TBNA under moderate sedation were quasi-randomized into HFNO and SAD groups. The episodes and duration of hypoxia and the lowest level of oxygen saturation were the primary outcome measured. Results: A total of twenty-four patients were taken into the study of which 10 were in the HFNO group and 14 were in the SAD group with an equal number of males and females. The duration of the procedure in both the groups was similar (45±20 mins in HFNO vs 44±17 in the SAD group). Mean lowest oxygen saturation in the HFNO group was (93.5%±4), which was statistically significant in comparison to the SAD group (90±6). In both groups, the maximum hypoxia occurred during the early phase of the procedure. However, both the groups were similar for the cumulative duration of hypotension (140 secs in HFNO vs 55 secs in SAD) and bradycardia (25 secs in HFNO vs. 40 secs in SAD). Conclusion: HFNO can be a good alternative to the SAD and could be used safely and efficiently in the cohort of population in patients undergoing EBUS TBNA.
Keywords: High flow nasal oxygenation; Endobronchial Ultrasound-guided Transbronchial Needle Aspiration; Supraglottic airway devices
Analysis of wind velocity and release angle effects on discus throw using computational fluid dynamics
The aim of this paper is to study the aerodynamics of discus throw. A comparison of numerical and experimental performance of discus throw with and without rotation was carried out using the analysis of lift and drag coefficients. Initial velocity corresponding to variation angle of around 35.5° was simulated. Boundary condition, on the top and bottom boundary edges of computational domain, was imposed in order to eliminate external influences on the discus; a wind resistance was calculated for the velocity values of 25 and 27 m/s. The results indicate that the flight distance (D) was strongly affected by the drag coefficient, the initial velocity, the release angle and the direction of wind velocity. It was observed that these variables change as a function of discus rotation. In this study, results indicate a good agreement of D between experimental values and numerical results.info:eu-repo/semantics/publishedVersio
Modelling Propelling Force in Swimming Using Numerical Simulations
In the sports field, numerical simulation techniques have been shown to provide useful
information about performance and to play an important role as a complementary tool to
physical experiments. Indeed, this methodology has produced significant improvements in
equipment design and technique prescription in different sports (Kellar et al., 1999; Pallis et
al., 2000; Dabnichki & Avital, 2006). In swimming, this methodology has been applied in
order to better understand swimming performance. Thus, the numerical techniques have
been addressed to study the propulsive forces generated by the propelling segments
(Rouboa et al., 2006; Marinho et al., 2009a) and the hydrodynamic drag forces resisting
forward motion (Silva et al., 2008; Marinho et al., 2009b).
Although the swimmer’s performance is dependent on both drag and propulsive forces,
within this chapter the focus is only on the analysis of the propulsive forces. Hence, this
chapter covers topics in swimming propelling force analysis from a numerical simulation
technique perspective. This perspective means emphasis on the fluid mechanics and
computational fluid dynamics methodology applied in swimming investigations. One of the
main aims for performance (velocity) enhancement of swimming is to maximize propelling
forces whilst not increasing drag forces resisting forward motion, for a given trust. This
chapter will concentrate on numerical simulation results, considering the scientific
simulation point-of-view, for this practical application in swimming
Toxicokinetics of bisphenol-S and its glucuronide in plasma and urine following oral and dermal exposure in volunteers for the interpretation of biomonitoring data
The measurement of bisphenol-S (BPS) and its glucurono-conjugate (BPSG) in urine may be used for the biomonitoring of exposure in populations. However, this requires a thorough knowledge of their toxicokinetics. The time courses of BPS and BPSG were assessed in accessible biological matrices of orally and dermally exposed volunteers. Under the approval of the Research Ethics Committee of the University of Montreal, six volunteers were orally exposed to a BPS-d8 deuterated dose of 0.1 mg/kg body weight (bw). One month later, 1 mg/kg bw of BPS-d8 were applied on 40 cm2 of the forearm and then washed 6 h after application. Blood samples were taken prior to dosing and at fixed time periods over 48 h after treatment; complete urine voids were collected pre-exposure and at pre-established intervals over 72 h postdosing. Following oral exposure, the plasma concentration–time courses of BPS-d8 and BPSG-d8 over 48 h evolved in parallel, and showed a rapid appearance and elimination. Average peak values (±SD) were reached at 0.7 ± 0.1 and 1.1 ± 0.4 h postdosing and mean (±SD) apparent elimination half-lives (t½) of 7.9 ± 1.1 and 9.3 ± 7.0 h were calculated from the terminal phase of BPS-d8 and BPSG-d8 in plasma, respectively. The fraction of BPS-d8 reaching the systemic circulation unchanged (i.e. bioavailability) was further estimated at 62 ± 5% on average (±SD) and the systemic plasma clearance at 0.57 ± 0.07 L/kg bw/h. Plasma concentration–time courses and urinary excretion rate profiles roughly evolved in parallel for both substances, as expected. The average percent (±SD) of the administered dose recovered in urine as BPS-d8 and BPSG-d8 over the 0–72 h period postdosing was 1.72 ± 1.3 and 54 ± 10%. Following dermal application, plasma levels were under the lower limit of quantification (LLOQ) at most time points. However, peak values were reached between 5 and 8 h depending on individuals, suggesting a slower absorption rate compared to oral exposure. Similarly, limited amounts of BPS-d8 and its conjugate were recovered in urine and peak excretion rates were reached between 5 and 11 h postdosing. The average percent (±SD) of the administered dose recovered in urine as BPS-d8 and BPSG-d8 was about 0.004 ± 0.003 and 0.09 ± 0.07%, respectively. This study provided greater precision on the kinetics of this contaminant in humans and, in particular, evidenced major differences between BPA and BPS kinetics with much higher systemic levels of active BPS than BPA, an observation explained by a higher oral bioavailability of BPS than BPA. These data should also be useful in developing a toxicokinetic model for a better interpretation of biomonitoring data
The gliding phase in swimming: the effect of water depth
Aiming to achieve higher performances, swimmers
should maximize each component of swimming races. During
starts and turns, the gliding phase represents a determinant part of these
race components. Thus, the depth position allowing minimizing the hydrodynamic
drag force represents an important concern in swimming
research. The aim of this study was to analyse the effect of depth on
drag during the underwater gliding, using computational fluid dynamic
Parametric investigations of short length hydro-dynamically lubricated conical journal bearing
Due to the growing need for compact size fluid film bearings, efforts are being made to explore the performance of hydro-dynamically lubricated short length conical journal bearing. The combined radial and axial load carrying features of these bearings emerge as a better option to replace the two separate bearings (journal and thrust pad bearings) employed in turbo-machines and other applications. Thus, in this study, attempts have been made to investigate the performance of conical hydrodynamic journal bearing by using finite element analysis. The bearings have been investigated for semi-cone angle (γ = 10°), aspect ratio (λ = 0.5, 0.8, 1.0), journal speed (v = 2.6, 5.2 m/s) and load variations in terms of eccentricity ratio (ε) up to 0.6. Results have been presented in terms of radial and axial load carrying capacity, stiffness coefficients, damping coefficients and threshold speed. Results from the present study reveal that load carrying capacity is improved with higher aspect ratio; whereas threshold speed decreases with the increase of eccentricity ratio and aspect ratio
Long-Term Genomic and Epigenomic Dysregulation as a Consequence of Prenatal Alcohol Exposure: A Model for Fetal Alcohol Spectrum Disorders
There is abundant evidence that prenatal alcohol exposure leads to a range of behavioral and cognitive impairments, categorized under the term fetal alcohol spectrum disorders (FASDs). These disorders are pervasive in Western cultures and represent the most common preventable source of neurodevelopmental disabilities. The genetic and epigenetic etiology of these phenotypes, including those factors that may maintain these phenotypes throughout the lifetime of an affected individual, has become a recent topic of investigation. This review integrates recent data that has progressed our understanding FASD as a continuum of molecular events, beginning with cellular stress response and ending with a long-term footprint of epigenetic dysregulation across the genome. It reports on data from multiple ethanol-treatment paradigms in mouse models that identify changes in gene expression that occur with respect to neurodevelopmental timing of exposure and ethanol dose. These studies have identified patterns of genomic alteration that are dependent on the biological processes occurring at the time of ethanol exposure. This review also adds to evidence that epigenetic processes such as DNA methylation, histone modifications, and non-coding RNA regulation may underlie long-term changes to gene expression patterns. These may be initiated by ethanol-induced alterations to DNA and histone methylation, particularly in imprinted regions of the genome, affecting transcription which is further fine-tuned by altered microRNA expression. These processes are likely complex, genome-wide, and interrelated. The proposed model suggests a potential for intervention, given that epigenetic changes are malleable and may be altered by postnatal environment. This review accentuates the value of mouse models in deciphering the molecular etiology of FASD, including those processes that may provide a target for the ammelioration of this common yet entirely preventable disorder
THE EFFECT OF WEARING A CAP ON THE SWIMMER PASSIVE DRAG
The purpose of this study was to analyse the effect of wearing a cap on swimmer passive drag. A computational fluid dynamics analysis was carried-out to determine the hydrodynamic drag of a female swimmer’s model: (i) wearing a swimming cap and; (ii) with no cap. The three-dimensional surface geometry of a female swimmer’s model with cap and with no cap was acquired through standard commercial laser scanner. Passive drag force and drag coefficient were computed with the swimmer in a streamlined position. Higher hydrodynamic drag values were determined when the swimmer was with no cap in comparison with the situation when the swimmer was wearing a cap. In conclusion, one can state that wearing a swim cap may positively influence swimmer’s hydrodynamics
Transfer learning for galaxy feature detection: Finding Giant Star-forming Clumps in low redshift galaxies using Faster R-CNN
Giant Star-forming Clumps (GSFCs) are areas of intensive star-formation that
are commonly observed in high-redshift (z>1) galaxies but their formation and
role in galaxy evolution remain unclear. High-resolution observations of
low-redshift clumpy galaxy analogues are rare and restricted to a limited set
of galaxies but the increasing availability of wide-field galaxy survey data
makes the detection of large clumpy galaxy samples increasingly feasible. Deep
Learning, and in particular CNNs, have been successfully applied to image
classification tasks in astrophysical data analysis. However, one application
of DL that remains relatively unexplored is that of automatically identifying
and localising specific objects or features in astrophysical imaging data. In
this paper we demonstrate the feasibility of using Deep learning-based object
detection models to localise GSFCs in astrophysical imaging data. We apply the
Faster R-CNN object detection framework (FRCNN) to identify GSFCs in low
redshift (z<0.3) galaxies. Unlike other studies, we train different FRCNN
models not on simulated images with known labels but on real observational data
that was collected by the Sloan Digital Sky Survey Legacy Survey and labelled
by volunteers from the citizen science project `Galaxy Zoo: Clump Scout'. The
FRCNN model relies on a CNN component as a `backbone' feature extractor. We
show that CNNs, that have been pre-trained for image classification using
astrophysical images, outperform those that have been pre-trained on
terrestrial images. In particular, we compare a domain-specific CNN -`Zoobot' -
with a generic classification backbone and find that Zoobot achieves higher
detection performance and also requires smaller training data sets to do so.
Our final model is capable of producing GSFC detections with a completeness and
purity of >=0.8 while only being trained on ~5,000 galaxy images.Comment: Accepted for publication in RASTI, 22 page
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