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International Journal of Sports... Jun 2021To quantify the demands of specific on- and off-court sessions, using internal and external training load metrics, in elite squash.
PURPOSE
To quantify the demands of specific on- and off-court sessions, using internal and external training load metrics, in elite squash.
METHODS
A total of 15 professional squash players (11 males and 4 females) wore a 100-Hz triaxial accelerometer/global positioning system unit and heart rate monitor during on-court "Group," "Feeding," "Ghosting," "Matchplay," and off-court "Conditioning" sessions across a 2-week in-season microcycle. Comparisons of absolute training load (total values) and relative intensity (per minute) were made between sessions for internal (session rating of perceived exertion, differential rating of perceived exertion, TRIMP) and external (Playerload, very high-intensity movements [>3.5 m·s-2]) metrics.
RESULTS
The Group sessions were the longest (79 [12] min), followed by Feeding (55 [15] min), Matchplay (46 [17] min), Conditioning (37 [9] min), and Ghosting (35 [6] min). Time >90% maximum heart rate was the lowest during Feeding (vs all others P < .05) but other sessions were not different (all P > .05). Relative Playerload during Conditioning (14.3 [3.3] arbitrary unit [a.u.] per min, all P < .05) was higher than Ghosting (7.5 [1.2] a.u./min) and Matchplay (6.9 [1.5] a.u./min), with no difference between these 2 sessions (P ≥ .999). Conditioning produced the highest Playerloads (519 [153] a.u., all P < .001), with the highest on-court Playerloads from Group (450 [94] a.u., all P < .001). The highest session rating of perceived exertion (all P < .001), Edward's TRIMP (all P < .001), and TEAM-TRIMP (all P < .019) occurred during the Group sessions.
CONCLUSIONS
Squash Matchplay does not systematically produce the highest training intensities and loads. Group sessions provide the highest training loads for many internal and external parameters and, therefore, play a central role within the training process. These findings facilitate planning or adjustment of intensity, volume, and frequency of sessions to achieve desirable physical outcomes.
Topics: Female; Humans; Male; Movement; Physical Conditioning, Human; Physical Exertion; Racquet Sports; Seasons; Soccer
PubMed: 33547264
DOI: 10.1123/ijspp.2020-0306 -
Pharmaceutical Statistics Jan 2022Exposure-adjusted event rate is a quantity often used in clinical trials to describe average event count per unit of person-time. The event count may represent the... (Review)
Review
Exposure-adjusted event rate is a quantity often used in clinical trials to describe average event count per unit of person-time. The event count may represent the number of patients experiencing first (incident) event episode, or the total number of event episodes, including recurring events. For inference about difference in the exposure-adjusted rates between interventions, many methods of interval estimation rely on the assumption of Poisson distribution for the event counts. These intervals may suffer from substantial undercoverage both, asymptotically due to extra-Poisson variation, and in the settings with rare events even when the Poisson assumption is satisfied. We review asymptotically robust methods of interval estimation for the rate difference that do not depend on distributional assumptions for the event counts, and propose a modification of one of these methods. The new interval estimator has asymptotically nominal coverage for the rate difference with an arbitrary distribution of event counts, and good finite sample properties, avoiding substantial undercoverage with small samples, rare events, or over-dispersed data. The proposed method can handle covariate adjustment and can be implemented with commonly available software. The method is illustrated using real data on adverse events in a clinical trial.
Topics: Causality; Confidence Intervals; Humans; Poisson Distribution; Randomized Controlled Trials as Topic; Software
PubMed: 34342122
DOI: 10.1002/pst.2155 -
Medical Ultrasonography May 2022Contrast-enhanced ultrasound (CEUS) appears to be a promising application for the diagnosis of parotid gland tumours. We aimed to systematically review and meta-analyse... (Meta-Analysis)
Meta-Analysis Review
AIM
Contrast-enhanced ultrasound (CEUS) appears to be a promising application for the diagnosis of parotid gland tumours. We aimed to systematically review and meta-analyse the ability of CEUS in distinguishing benign from malignant parotid gland tumours.
MATERIAL AND METHODS
PubMed was searched for relevant studies. Data on area under time intensity curve (AUC) in arbitrary unit (AU), and mean transit time (MTT) in seconds (sec) were analysed using the Cochrane Review Manager Software.
RESULTS
Nine studies met the eligibility criteria comprising a total number of 498 parotid gland tumours (benign, number (n)=423; malignant, n=75). Descriptive evaluation of parotid gland tumours following CEUS administration showed overlap characteristics in benign and malignancies. Two publications assessed AUC and MTT in 72 and 60 parotid gland tumours, respectively. AUC was significantly lower in benign compared to malignant tumours following contrast administration (AUC, mean difference (MD) -266.77 AU, 95% confidence intervals (CI) -433.22, -100.33, p=0.002). No significant different in MTT between benign and malignant tumours (p=0.12). Heterogeneity was statistically significant in AUC (p=0.04) and MTT (p<0.00001).
CONCLUSION
Descriptive evaluation of parotid gland tumours showed overlap CEUS characteristics. Perfusion related CEUS parameters analysis is promising in differentiating benign parotid tumours from malignancies.
Topics: Contrast Media; Diagnosis, Differential; Humans; Parotid Gland; Parotid Neoplasms; Perfusion; Ultrasonography
PubMed: 34216453
DOI: 10.11152/mu-3119 -
Scientific Reports Jan 2018Architectured materials with rationally designed geometries could be used to create mechanical metamaterials with unprecedented or rare properties and functionalities....
Architectured materials with rationally designed geometries could be used to create mechanical metamaterials with unprecedented or rare properties and functionalities. Here, we introduce "shape-matching" metamaterials where the geometry of cellular structures comprising auxetic and conventional unit cells is designed so as to achieve a pre-defined shape upon deformation. We used computational models to forward-map the space of planar shapes to the space of geometrical designs. The validity of the underlying computational models was first demonstrated by comparing their predictions with experimental observations on specimens fabricated with indirect additive manufacturing. The forward-maps were then used to devise the geometry of cellular structures that approximate the arbitrary shapes described by random Fourier's series. Finally, we show that the presented metamaterials could match the contours of three real objects including a scapula model, a pumpkin, and a Delft Blue pottery piece. Shape-matching materials have potential applications in soft robotics and wearable (medical) devices.
PubMed: 29343772
DOI: 10.1038/s41598-018-19381-3 -
Lab on a Chip Jun 2021Unsteady and pulsatile flows receive increasing attention due to their potential to enhance various microscale processes. Further, they possess significant relevance for...
Unsteady and pulsatile flows receive increasing attention due to their potential to enhance various microscale processes. Further, they possess significant relevance for microfluidic studies under physiological flow conditions. However, generating a precise time-dependent flow field with commercial, pneumatically operated pressure controllers remains challenging and can lead to significant deviations from the desired waveform. In this study, we present a method to correct such deviations and thus optimize pulsatile flows in microfluidic experiments using two commercial pressure pumps. Therefore, we first analyze the linear response of the systems to a sinusoidal pressure input, which allows us to predict the time-dependent pressure output for arbitrary pulsatile input signals. Second, we explain how to derive an adapted input signal, which significantly reduces deviations between the desired and actual output pressure signals of various waveforms. We demonstrate that this adapted pressure input leads to an enhancement of the time-dependent flow of red blood cells in microchannels. The presented method does not rely on any hardware modifications and can be easily implemented in standard pressure-driven microfluidic setups to generate accurate pulsatile flows with arbitrary waveforms.
Topics: Lab-On-A-Chip Devices; Microfluidics; Pulsatile Flow
PubMed: 34008605
DOI: 10.1039/d0lc01297a -
Medical Physics Aug 2023Agatston scoring, the traditional method for measuring coronary artery calcium, is limited in its ability to accurately quantify low-density calcifications, among other...
BACKGROUND
Agatston scoring, the traditional method for measuring coronary artery calcium, is limited in its ability to accurately quantify low-density calcifications, among other things. The inaccuracy of Agatston scoring is likely due partly to the arbitrary thresholding requirement of Agatston scoring.
PURPOSE
A calcium quantification technique that removes the need for arbitrary thresholding and is more accurate, sensitive, reproducible, and robust is needed. Improvements to calcium scoring will likely improve patient risk stratification and outcome.
METHODS
The integrated Hounsfield technique was adapted for calcium scoring (integrated calcium mass). Integrated calcium mass requires no thresholding and includes all calcium information within an image. This study utilized phantom images acquired by G van Praagh et al., with calcium hydroxyapatite (HA) densities in the range of 200-800 mgHAcm to measure calcium according to integrated calcium mass and Agatston scoring. The calcium mass was known, which allowed for accuracy, reproducibility, sensitivity, and robustness comparisons between integrated calcium mass and Agatston scoring. Multiple CT vendors (Canon, GE, Philips, Siemens) were used during the image acquisition phase, which provided a more robust comparison between the two calcium scoring techniques. Three calcification inserts of different diameters (1, 3, and 5 mm) and different HA densities (200, 400, and 800 mgHAcm ) were placed within the phantom. The effect of motion was also analyzed using a dynamic phantom. All dynamic phantom calcium inserts were 5.0 ± 0.1 mm in diameter with a length of 10.0 ± 0.1 mm. The four different densities were 196 ± 3, 380 ± 2, 408 ± 2, and 800 ± 2 mgHAcm .
RESULTS
Integrated calcium mass was more accurate than Agatston scoring for stationary scans ( , ) and motion affected scans ( , ). On average, integrated calcium mass was more reproducible than Agatston scoring for two of the CT vendors. The percentage of false-negative and false-positive calcium scores were lower for integrated calcium mass (15.00%, 0.00%) than Agatston scoring (28.33%, 6.67%). Integrated calcium mass was more robust to changes in scan parameters than Agatston scoring.
CONCLUSIONS
The results of this study indicate that integrated calcium mass is more accurate, reproducible, and sensitive than Agatston scoring on a variety of different CT vendors. The substantial reduction in false-negative scores for integrated calcium mass is likely to improve risk-stratification for patients undergoing calcium scoring and their potential outcome.
Topics: Humans; Calcium; Coronary Vessels; Reproducibility of Results; Calcinosis; Motion
PubMed: 36852776
DOI: 10.1002/mp.16326 -
Advanced Materials (Deerfield Beach,... Nov 2023Film-type shape-configurable speakers with tunable sound directivity are in high demand for wearable electronics. Flexible, thin thermoacoustic (TA) loudspeakers-which...
Film-type shape-configurable speakers with tunable sound directivity are in high demand for wearable electronics. Flexible, thin thermoacoustic (TA) loudspeakers-which are free from bulky vibrating diaphragms-show promise in this regard. However, configuring thin TA loudspeakers into arbitrary shapes is challenging because of their low sound pressure level (SPL) under mechanical deformations and low conformability to other surfaces. By carefully controlling the heat capacity per unit area and thermal effusivity of an MXene conductor and substrates, respectively, it fabricates an ultrathin MXene-based TA loudspeaker exhibiting high SPL output (74.5 dB at 15 kHz) and stable sound performance for 14 days. Loudspeakers with the parylene substrate, whose thickness is less than the thermal penetration depth, generated bidirectional and deformation-independent sound in bent, twisted, cylindrical, and stretched-kirigami configurations. Furthermore, it constructs parabolic and spherical versions of ultrathin, large-area (20 cm × 20 cm) MXene-based TA loudspeakers, which display sound-focusing and 3D omnidirectional-sound-generating attributes, respectively.
PubMed: 37740254
DOI: 10.1002/adma.202306637 -
Environmental Science and Pollution... Aug 2021This paper contributes to the environmental literature by (i) demonstrating that the estimated coefficients and the statistical significance of the non-leading terms in...
This paper contributes to the environmental literature by (i) demonstrating that the estimated coefficients and the statistical significance of the non-leading terms in quadratic, cubic, and quartic logarithmic environmental Kuznets curve (EKC) specifications are arbitrary and should therefore not be used to choose the preferred specification and (ii) detailing a proposed general-to-specific type methodology for choosing the appropriate specifications when attempting to estimate higher-order polynomials such as cubic and quartic logarithmic EKC relationships. Testing for the existence and shape of the well-known EKC phenomenon is a hot topic in the environmental economics literature. The conventional approach widely employs quadratic and cubic specifications and more recently also the quartic specification, where the variables are in logarithmic form. However, it is important that researchers understand whether the estimated EKC coefficients, turning points, and elasticities are statistically acceptable, economically interpretable, and comparable. In addition, it is vital that researchers have a clear structured non-arbitrary methodology for determining the preferred specification and hence shape of the estimated EKC. We therefore show mathematically and empirically the arbitrary nature of estimated non-leading coefficients in quadratic, cubic, and quartic logarithmic EKC specifications, being dependent upon the units of measurement chosen for the independent variables (e.g. dependent upon a rescaling of the variables such as moving from $m to $bn). Consequently, the practice followed in many previously papers, whereby the estimates of the non-leading terms are used in the decision to choose the preferred specification of an estimated EKC relationship, is incorrect and should not be followed since it potentially could lead to misleading conclusions. Instead, it should be based upon the sign and statistical significance of the estimated coefficients of the leading terms, the location of turning point(s), and the sign and statistical significance of the estimated elasticities. Furthermore, we suggest that researchers should follow a proposed general-to-specific type methodology for choosing the appropriate order of polynomials when attempting to estimate higher-order polynomial logarithmic EKCs.
Topics: Algorithms; Carbon Dioxide; Economic Development; Humans
PubMed: 33797046
DOI: 10.1007/s11356-021-13463-y -
Cell and Tissue Banking Jun 2016To investigate the de-orientation effect of DSAEK grafts by observing the cross patterns and polarization power of human donor corneas using a polarizing device...
To investigate the de-orientation effect of DSAEK grafts by observing the cross patterns and polarization power of human donor corneas using a polarizing device (Lumaxis(®)). Forty human donor corneas were placed in small petri-plates with epithelial side facing up. Polarizing power (arbitrary unit) and crosses were monitored and recorded by the software. The tissue was marked at 'Superior' position to ensure that the base and the polarizer are in alignment with each other after the cut. The anterior lamellar cut was performed using microkeratome. The lenticule was placed back in the same position as marked to mimic the alignment. The tissue was further rotated by 45° ensuring that the base of the cornea and the polarizer were in alignment. The polarization power and 'crosses' were identified at each step. The average of forty corneas from pre-cut to post-45° angular change showed statistically significant difference (p < 0.05) in terms of polarizing power. The cross-shaped pattern deformed and lost the sharpness towards 45° angle. However, multiple variances in terms of 'cross-patterns' were observed throughout the study. Lumaxis(®) was able to determine the worst quality tissue in terms of polarization (no black zone and crosses). Despite the quality of cross pattern which can be used as an additional objective parameter to evaluate the optical properties of the corneal tissue, this preliminary study needs to be further justified in terms of clinical relevance whether polarization changes with oriented or de-oriented grafts have any effects and consequences on the visual acuity.
Topics: Cornea; Humans; Image Processing, Computer-Assisted; Microscopy, Polarization; Tissue Donors
PubMed: 26920874
DOI: 10.1007/s10561-016-9546-9 -
The European Journal of Health... Aug 2022From both the methodological point of view and standardization of methodology, little attention has been paid to the estimation of direct costs in evaluation of... (Review)
Review
From both the methodological point of view and standardization of methodology, little attention has been paid to the estimation of direct costs in evaluation of healthcare technologies. The objective is to revise the recommendations on direct costs provided in European economic evaluation guidelines and to identify the commonalities and divergences among them. To achieve this, a comprehensive search through several online databases was performed resulting in 41 documents from 26 European countries, be they economic evaluation guidelines or costing guidelines. The results show a large disparity in methodologies used in estimation of direct costs to be included in economic evaluations of health technologies recommended by European countries. A lack of standardization of cost estimation methodologies influences arbitrariness in selecting costs of resources included in economic evaluations of medicinal products or any other technologies and, therefore, in decision making process necessary to introduce new technology. In addition, this heterogeneity poses a major challenge for identifying factors that could affect the variability of unit costs across countries.
Topics: Biomedical Technology; Cost-Benefit Analysis; Europe; Humans
PubMed: 34825296
DOI: 10.1007/s10198-021-01414-w