Influence of ultrasound machine settings on quantitative measures derived from spatial frequency analysis of muscle tissue

Background Ultrasound is a powerful tool for diagnostic purposes and provides insight into both normal and pathologic tissue structure. Spatial frequency analysis (SFA) methods characterize musculoskeletal tissue organization from ultrasound images. Both sonographers in clinical imaging and researchers may alter a minimized range of ultrasound settings to optimize image quality, and it is important to know how these small adjustments of these settings affect SFA parameters. The purpose of this study was to investigate the effects of making small adjustments in a typical default ultrasound machine setting on extracted spatial frequency parameters (peak spatial frequency radius (PSFR), Mmax, Mmax%, and Sum) in the biceps femoris muscle. Methods Longitudinal B-mode images were collected from the biceps femoris muscle in 36 participants. The window depth, foci locations, and gain were systematically adjusted consistent with clinical imaging procedures for a total of 27 images per participant. Images were analyzed by identifying a region of interest (ROI) in the middle portion of the muscle belly in a template image and using a normalized two-dimensional cross-correlation technique between the template image and subsequent images. The ROI was analyzed in the frequency domain using conventional SFA methods. Separate linear mixed effects models were run for each extracted parameter. Results PSFR was affected by modifications in focus location only (p \u3c 0.001) with differences noted between all locations. Mmax% was influenced by the interaction of gain and focus location (p \u3c 0.001) but was also independently affected by increasing window depth (p \u3c 0.001). Both Mmax and Sum parameters were sensitive to small changes in machine settings with the interaction of focus location and window depth (p \u3c 0.001 for both parameters) as well as window depth and gain (p \u3c 0.001 for both) influencing the extracted values. Conclusions Frequently adjusted imaging settings influence some SFA statistics. PSFR and Mmax% appear to be most robust to small changes in image settings, making them best suited for comparison across individuals and between studies, which is appealing for the clinical utility of the SFA method

Association of physical activity on memory interference: Boston Puerto Rican Health Study

Background: The objective of this study was to evaluate the association between habitual physical activity engagement on memory interference. The present analysis used cross-sectional data from the Boston Puerto Rican Health Study (n=1,241; mean age= 57.2; 72.1% female). Methods: Physical activity was evaluated via self-report. Memory interference was evaluated using a word-list paradigm. The memory task included learning a list of 16 words (List A; 5 trials), followed by a distractor list (List B), and then an immediate recall of List A. Proactive interference occurs when preceding stimuli (e.g., Trial 1 and Trial 5 of List A) interferes with performance on a subsequent stimuli (List B). Retroactive interference occurs when subsequent stimuli (List B) interferes with the recall of previously encoded stimuli (Trial 5). Results: For proactive interference, there was no association between physical activity and the difference between performance on List B and Trial 1 of List A (β=0.00001; P= 0.96). Similarly, for retroactive interference, there was no association between physical activity and the difference between the short delay recall and Trial 5 of List A (β=0.0002; P= 0.50). Conclusion: The present study did not observe an association between habitual physical activity on attenuating memory interference

Prediction modeling for Board of Certification exam success for a professional master’s athletic training program

Introduction: The Commission on Accreditation of Athletic Training Education mandates accredited athletic training programs have a minimum, three-year aggregate, first-attempt pass rate on the Board of Certification (BOC) examination of 70%. No studies have examined first-attempt BOC exam success for students enrolled in a professional master’s athletic training program (PMATP). Purpose: The purpose of this study was to identify factors associated with first-attempt success on the BOC examination for PMATP students. Methods: This cohort designed study used common application data from subjects’ university and PMATP applications to create prediction models to identify those factors that predict first-attempt success on the BOC exam. Results: A four-factor model was produced to predict first-attempt BOC exam success. Both models demonstrated a student with two, three or more predictors had an odds ratio of 16.0 or greater, a relative frequency of success of 1.45 or greater, and correctly predicted first-attempt success on the BOC exam over 92% of the time. Conclusions: It is possible to predict success on the BOC exam for students from a PMATP based on common application data. Recommendations: Although this project involved predicting success on the athletic training certification exam, the procedures and methods used could be adapted to any academic program

Association of physical activity on memory interference: Boston Puerto Rican Health Study

Background: The objective of this study was to evaluate the association between habitual physical activity engagement on memory interference. The present analysis used cross-sectional data from the Boston Puerto Rican Health Study (n=1,241; mean age= 57.2; 72.1% female). Methods: Physical activity was evaluated via self-report. Memory interference was evaluated using a word-list paradigm. The memory task included learning a list of 16 words (List A; 5 trials), followed by a distractor list (List B), and then an immediate recall of List A. Proactive interference occurs when preceding stimuli (e.g., Trial 1 and Trial 5 of List A) interferes with performance on a subsequent stimuli (List B). Retroactive interference occurs when subsequent stimuli (List B) interferes with the recall of previously encoded stimuli (Trial 5). Results: For proactive interference, there was no association between physical activity and the difference between performance on List B and Trial 1 of List A (β=0.00001; P=0.96). Similarly, for retroactive interference, there was no association between physical activity and the difference between the short delay recall and Trial 5 of List A (β=0.0002; P=0.50). Conclusion: The present study did not observe an association between habitual physical activity on attenuating memory interference

Observed size distribution changes in American lobsters over a 12-year period in southwestern Nova Scotia, Canada

Size distribution and size frequency information of American lobsters (Homarus americanus) are often used to help estimate the age distributions, and reproductive output for the species and to guide the determination of appropriate minimum legal sizes for the fishery. This study used truncated linear regression models to estimate the effects of sampling year, sampling month, lobster sex and water depth on the lobster size. A dataset of almost 130,000 trap–caught lobsters from the two most important lobster fishing areas of Atlantic Canada collected over a 12-year period (2004–2015) was analyzed. It was shown that truncated models can help to account for biases due to the trap sampling method from vessels and from wharf samplings. There were significant annual and seasonal changes in size distribution, and data collected outside the fishing season showed a significant increase in carapace length in 2014 and 2015, potentially reflecting a northward shift of the range of lobster populations due to more favourable settlement and recruitment habitats. Size also increased in late summer, likely due to moult. Our results demonstrated that landed lobsters, especially females, were smaller than the predicted size-at-maturity in the region (96.5 mm carapace length), which could have long-term repercussions for the stock’s reproductive potential

A Search for the Most Massive Galaxies. II. Structure, Environment and Formation

We study a sample of 43 early-type galaxies, selected from the SDSS because they appeared to have velocity dispersion > 350 km/s. High-resolution photometry in the SDSS i passband using HRC-ACS on board the HST shows that just less than half of the sample is made up of superpositions of two or three galaxies, so the reported velocity dispersion is incorrect. The other half of the sample is made up of single objects with genuinely large velocity dispersions. None of these objects has sigma larger than 426 +- 30 km/s. These objects define rather different relations than the bulk of the early-type galaxy population: for their luminosities, they are the smallest, most massive and densest galaxies in the Universe. Although the slopes of the scaling relations they define are rather different from those of the bulk of the population, they lie approximately parallel to those of the bulk "at fixed sigma". These objects appear to be of two distinct types: the less luminous (M_r>-23) objects are rather flattened and extremely dense for their luminosities -- their properties suggest some amount of rotational support and merger histories with abnormally large amounts of gaseous dissipation. The more luminous objects (M_r<-23) tend to be round and to lie in or at the centers of clusters. Their properties are consistent with the hypothesis that they are BCGs. Models in which BCGs form from predominantly radial mergers having little angular momentum predict that they should be prolate. If viewed along the major axis, such objects would appear to have abnormally large sigma for their sizes, and to be abnormally round for their luminosities. This is true of the objects in our sample once we account for the fact that the most luminous galaxies (M_r<-23.5), and BCGs, become slightly less round with increasing luminosity.Comment: 21 pages, 19 figures, accepted for publication in MNRA

Extended Lyman alpha emission around bright quasars

Quasars trace the most massive structures at high redshifts and their presence may influence the evolution of the massive host galaxies. We study the extended Lyman alpha emission line regions (EELRs) around seven bright, mostly radio-quiet quasars (QSOs) at 2.7<z<4.5, and compare luminosities with EELRs around radio-loud QSOs reported in the literature. Using integral field spectroscopy, we analyse the morphology and kinematics of the quiescent Lya EELRs around the QSOs. We find evidence for the presence of EELRs around four radio-quiet and one radio-loud QSO. All EELRs appear asymmetric and the optically brightest QSOs also have the brightest Lya nebulae. For the two brightest nebulae we find velocities between ~600 km s^-1 at the QSO position to ~200 km s^-1 at a distance of 3-4 arcsec from the QSO and surface flux densities up to 2-3*10^{-16} erg cm^-2 s^-1 arcsec^-2. The five EELRs have total Lya luminosities which correspond to ~0.5% of the luminosities from the QSOs broad Lya emission lines. This fraction is an order of magnitude smaller than found for EELRs around radio-loud, steep spectrum QSOs reported in the literature. While the nebulae luminosities are correlated with the QSO Lya luminosities, we find that nebulae luminosities are not correlated with the central QSO ionising fluxes. The presence of gas in the EELRs can be interpreted based on two competing scenarios: either from quasar feedback mechanisms, or from infalling matter. Apart from these two effects, the Lya flux around radio-loud objects can be enhanced due to interactions with the radio jets. The relatively fainter nebulae around radio-quiet QSOs compared to lobe-dominated radio-loud QSOs can be ascribed to this effect, or to significant differences in the environments between the two classes.Comment: 15 pages, A&A accepted. Section 4 revise

The effects of hip- vs. knee-dominant hamstring exercise on biceps femoris morphology, strength, and sprint performance: a randomized intervention trial protocol

Background The hamstrings are an important muscle group that contribute to horizontal force during sprint acceleration and are also the most injured muscle group in running-based sports. Given the significant time loss associated with hamstrings injury and impaired sprinting performance following return to sport, identifying exercises that drive adaptations that are both protective of strain injury and beneficial to sprint performance is important for the strength and conditioning professional. This paper describes the study protocol investigating the effects of a 6-week training program using either the hip-dominant Romanian deadlift (RDL) or the knee-dominant Nordic hamstring exercise (NHE) on hamstring strain injury risk factors and sprint performance. Methods A permuted block randomized (1:1 allocation) intervention trial will be conducted involving young, physically-active men and women. A target sample size of 32 will be recruited and enrolled participants will undergo baseline testing involving extended-field-of-view ultrasound imaging and shear wave elastography of the biceps femoris long head muscle, maximal hamstrings strength testing in both the RDL and NHE, and on-field sprint performance and biomechanics. Participants will complete the 6-week training intervention using either the RDL or NHE, according to group allocation. Baseline testing will be repeated at the end of the 6-week intervention followed by 2 weeks of detraining and a final testing session. The primary outcome will be regional changes in fascicle length with secondary outcomes including pennation angle, muscle cross sectional area, hamstring strength, and maximal sprint performance and biomechanics. An exploratory aim will determine changes in shear wave velocity. Discussion Despite extensive research showing the benefits of the NHE on reducing hamstring strain injury risk, alternative exercises, such as the RDL, may offer similar or potentially even greater benefits. The findings of this study will aim to inform future researchers and practitioners investigating alternatives to the NHE, such as the RDL, in terms of their effectiveness in reducing rates of hamstring strain injury in larger scale prospective intervention studies

Low-lying level structure of 56^{56}Cu and its implications on the rp process

The low-lying energy levels of proton-rich $^{56}$Cu have been extracted using in-beam $\gamma$-ray spectroscopy with the state-of-the-art $\gamma$-ray tracking array GRETINA in conjunction with the S800 spectrograph at the National Superconducting Cyclotron Laboratory at Michigan State University. Excited states in $^{56}$Cu serve as resonances in the $^{55}$Ni(p,$\gamma$)$^{56}$Cu reaction, which is a part of the rp-process in type I x-ray bursts. To resolve existing ambiguities in the reaction Q-value, a more localized IMME mass fit is used resulting in $Q=639\pm82$~keV. We derive the first experimentally-constrained thermonuclear reaction rate for $^{55}$Ni(p,$\gamma$)$^{56}$Cu. We find that, with this new rate, the rp-process may bypass the $^{56}$Ni waiting point via the $^{55}$Ni(p,$\gamma$) reaction for typical x-ray burst conditions with a branching of up to $\sim$40$\%$. We also identify additional nuclear physics uncertainties that need to be addressed before drawing final conclusions about the rp-process reaction flow in the $^{56}$Ni region.Comment: 8 pages, accepted for Phys. Rev.

Urinary ATP as an indicator of infection and inflammation of the urinary tract in patients with lower urinary tract symptoms

BACKGROUND: Adenosine-5'-triphosphate (ATP) is a neurotransmitter and inflammatory cytokine implicated in the pathophysiology of lower urinary tract disease. ATP additionally reflects microbial biomass thus has potential as a surrogate marker of urinary tract infection (UTI). The optimum clinical sampling method for ATP urinalysis has not been established. We tested the potential of urinary ATP in the assessment of lower urinary tract symptoms, infection and inflammation, and validated sampling methods for clinical practice. METHODS: A prospective, blinded, cross-sectional observational study of adult patients presenting with lower urinary tract symptoms (LUTS) and asymptomatic controls, was conducted between October 2009 and October 2012. Urinary ATP was assayed by a luciferin-luciferase method, pyuria counted by microscopy of fresh unspun urine and symptoms assessed using validated questionnaires. The sample collection, storage and processing methods were also validated. RESULTS: 75 controls and 340 patients with LUTS were grouped as without pyuria (n = 100), pyuria 1-9 wbc ?l(-1) (n = 120) and pyuria ?10 wbc ?l(-1) (n = 120). Urinary ATP was higher in association with female gender, voiding symptoms, pyuria greater than 10 wbc ?l(-1) and negative MSU culture. ROC curve analysis showed no evidence of diagnostic test potential. The urinary ATP signal decayed with storage at 23°C but was prevented by immediate freezing at ??-20°C, without boric acid preservative and without the need to centrifuge urine prior to freezing. CONCLUSIONS: Urinary ATP may have a role as a research tool but is unconvincing as a surrogate, clinical diagnostic marker