329 research outputs found
Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system
© 2019, The Author(s). The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate ( 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexionâextension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system
Further investigation of confirmed urinary tract infection (UTI) in children under five years: a systematic review.
Background: Further investigation of confirmed UTI in children aims to prevent renal scarring and future complications. Methods: We conducted a systematic review to determine the most effective approach to the further investigation of confirmed urinary tract infection (UTI) in children under five years of age. Results: 73 studies were included. Many studies had methodological limitations or were poorly reported. Effectiveness of further investigations: One study found that routine imaging did not lead to a reduction in recurrent UTIs or renal scarring. Diagnostic accuracy: The studies do not support the use of less invasive tests such as ultrasound as an alternative to renal scintigraphy, either to rule out infection of the upper urinary tract (LR- = 0.57, 95%CI: 0.47, 0.68) and thus to exclude patients from further investigation or to detect renal scarring (LR+ = 3.5, 95% CI: 2.5, 4.8). None of the tests investigated can accurately predict the development of renal scarring. The available evidence supports the consideration of contrast-enhanced ultrasound techniques for detecting vesico-ureteric reflux (VUR), as an alternative to micturating cystourethrography (MCUG) (LR+ = 14.1, 95% CI: 9.5, 20.8; LR- = 0.20, 95%CI: 0.13, 0.29); these techniques have the advantage of not requiring exposure to ionising radiation. Conclusion: There is no evidence to support the clinical effectiveness of routine investigation of children with confirmed UTI. Primary research on the effectiveness, in terms of improved patient outcome, of testing at all stages in the investigation of confirmed urinary tract infection is urgently required
How does study quality affect the results of a diagnostic meta-analysis?
Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited
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Bioavailability in soils
The consumption of locally-produced vegetables by humans may be an important exposure pathway for soil contaminants in many urban settings and for agricultural land use. Hence, prediction of metal and metalloid uptake by vegetables from contaminated soils is an important part of the Human Health Risk Assessment procedure. The behaviour of metals (cadmium, chromium, cobalt, copper, mercury, molybdenum, nickel, lead and zinc) and metalloids (arsenic, boron and selenium) in contaminated soils depends to a large extent on the intrinsic charge, valence and speciation of the contaminant ion, and soil properties such as pH, redox status and contents of clay and/or organic matter. However, chemistry and behaviour of the contaminant in soil alone cannot predict soil-to-plant transfer. Root uptake, root selectivity, ion interactions, rhizosphere processes, leaf uptake from the atmosphere, and plant partitioning are important processes that ultimately govern the accumulation ofmetals and metalloids in edible vegetable tissues. Mechanistic models to accurately describe all these processes have not yet been developed, let alone validated under field conditions. Hence, to estimate risks by vegetable consumption, empirical models have been used to correlate concentrations of metals and metalloids in contaminated soils, soil physico-chemical characteristics, and concentrations of elements in vegetable tissues. These models should only be used within the bounds of their calibration, and often need to be re-calibrated or validated using local soil and environmental conditions on a regional or site-specific basis.Mike J. McLaughlin, Erik Smolders, Fien Degryse, and Rene Rietr
UV-Green Iridescence Predicts Male Quality during Jumping Spider Contests
10.1371/journal.pone.0059774PLoS ONE84
miR-16 and miR-21 Expression in the Placenta Is Associated with Fetal Growth
BACKGROUND: Novel research has suggested that altered miRNA expression in the placenta is associated with adverse pregnancy outcomes and with potentially harmful xenobiotic exposures. We hypothesized that aberrant expression of miRNA in the placenta is associated with fetal growth, a measurable phenotype resulting from a number of intrauterine factors, and one which is significantly predictive of later life outcomes. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 107 primary, term, human placentas for expression of 6 miRNA reported to be expressed in the placenta and to regulate cell growth and development pathways: miR-16, miR-21, miR-93, miR-135b, miR-146a, and miR-182. The expression of miR-16 and miR-21 was markedly reduced in infants with the lowest birthweights (p<0.05). Logistic regression models suggested that low expression of miR-16 in the placenta predicts an over 4-fold increased odds of small for gestational age (SGA) status (pâ=â0.009, 95% CIâ=â1.42, 12.05). Moreover, having both low miR-16 and low miR-21 expression in the placenta predicts a greater increase in odds for SGA than having just low miR-16 or miR-21 expression (p<0.02), suggesting an additive effect of both of these miRNA. CONCLUSIONS/SIGNIFICANCE: Our study is one of the first to investigate placental miRNA expression profiles associated with birthweight and SGA status. Future research on miRNA whose expression is associated with in utero exposures and markers of fetal growth is essential for better understanding the epigenetic mechanisms underlying the developmental origins of health and disease
Sensitivity of the human auditory cortex to acoustic degradation of speech and non-speech sounds
The perception of speech is usually an effortless and reliable process even in highly adverse listening conditions. In addition to external sound sources, the intelligibility of speech can be reduced by degradation of the structure of speech signal itself, for example by digital compression of sound. This kind of distortion may be even more detrimental to speech intelligibility than external distortion, given that the auditory system will not be able to utilize sound source-specific acoustic features, such as spatial location, to separate the distortion from the speech signal. The perceptual consequences of acoustic distortions on speech intelligibility have been extensively studied. However, the cortical mechanisms of speech perception in adverse listening conditions are not well known at present, particularly in situations where the speech signal itself is distorted. The aim of this thesis was to investigate the cortical mechanisms underlying speech perception in conditions where speech is less intelligible due to external distortion or as a result of digital compression.
In the studies of this thesis, the intelligibility of speech was varied either by digital compression or addition of stochastic noise. Cortical activity related to the speech stimuli was measured using magnetoencephalography (MEG). The results indicated that degradation of speech sounds by digital compression enhanced the evoked responses originating from the auditory cortex, whereas addition of stochastic noise did not modulate the cortical responses. Furthermore, it was shown that if the distortion was presented continuously in the background, the transient activity of auditory cortex was delayed. On the perceptual level, digital compression reduced the comprehensibility of speech more than additive stochastic noise. In addition, it was also demonstrated that prior knowledge of speech content enhanced the intelligibility of distorted speech substantially, and this perceptual change was associated with an increase in cortical activity within several regions adjacent to auditory cortex.
In conclusion, the results of this thesis show that the auditory cortex is very sensitive to the acoustic features of the distortion, while at later processing stages, several cortical areas reflect the intelligibility of speech. These findings suggest that the auditory system rapidly adapts to the variability of the auditory environment, and can efficiently utilize previous knowledge of speech content in deciphering acoustically degraded speech signals.Puheen havaitseminen on useimmiten vaivatonta ja luotettavaa myös erittÀin huonoissa kuunteluolosuhteissa. Puheen ymmÀrrettÀvyys voi kuitenkin heikentyÀ ympÀristön hÀiriölÀhteiden lisÀksi myös silloin, kun puhesignaalin rakennetta muutetaan esimerkiksi pakkaamalla digitaalista ÀÀntÀ. TÀllainen hÀiriö voi heikentÀÀ ymmÀrrettÀvyyttÀ jopa ulkoisia hÀiriöitÀ voimakkaammin, koska kuulojÀrjestelmÀ ei pysty hyödyntÀmÀÀn ÀÀnilÀhteen ominaisuuksia, kuten ÀÀnen tulosuuntaa, hÀiriön erottelemisessa puheesta. Akustisten hÀiriöiden vaikutuksia puheen havaitsemiseen on tutkttu laajalti, mutta havaitsemiseen liittyvÀt aivomekanismit tunnetaan edelleen melko puutteelisesti etenkin tilanteissa, joissa itse puhesignaali on laadultaan heikentynyt. TÀmÀn vÀitöskirjan tavoitteena oli tutkia puheen havaitsemisen aivomekanismeja tilanteissa, joissa puhesignaali on vaikeammin ymmÀrrettÀvissÀ joko ulkoisen ÀÀnilÀhteen tai digitaalisen pakkauksen vuoksi.
VÀitöskirjan neljÀssÀ osatutkimuksessa lyhyiden puheÀÀnien ja jatkuvan puheen ymmÀrrettÀvyyttÀ muokattiin joko digitaalisen pakkauksen kautta tai lisÀÀmÀllÀ puhesignaaliin satunnaiskohinaa. PuheÀrsykkeisiin liittyvÀÀ aivotoimintaa tutkittiin magnetoenkefalografia-mittauksilla. Tutkimuksissa havaittiin, ettÀ kuuloaivokuorella syntyneet herÀtevasteet voimistuivat, kun puheÀÀntÀ pakattiin digitaalisesti. Sen sijaan puheÀÀniin lisÀtty satunnaiskohina ei vaikuttanut herÀtevasteisiin. Edelleen, mikÀli puheÀÀnien taustalla esitettiin jatkuvaa hÀiriötÀ, kuuloaivokuoren aktivoituminen viivÀstyi hÀiriön intensiteetin kasvaessa. Kuuntelukokeissa havaittiin, ettÀ digitaalinen pakkaus heikentÀÀ puheÀÀnien ymmÀrrettÀvyyttÀ voimakkaammin kuin satunnaiskohina. LisÀksi osoitettiin, ettÀ aiempi tieto puheen sisÀllöstÀ paransi merkittÀvÀsti hÀiriöisen puheen ymmÀrrettÀvyyttÀ, mikÀ heijastui aivotoimintaan kuuloaivokuoren viereisillÀ aivoalueilla siten, ettÀ ymmÀrrettÀvÀ puhe aiheutti suuremman aktivaation kuin heikosti ymmÀrrettÀvÀ puhe.
VÀitöskirjan tulokset osoittavat, ettÀ kuuloaivokuori on erittÀin herkkÀ puheÀÀnien akustisille hÀiriöille, ja myöhemmissÀ prosessoinnin vaiheissa useat kuuloaivokuoren viereiset aivoalueet heijastavat puheen ymmÀrrettÀvyyttÀ. Tulosten mukaan voi olettaa, ettÀ kuulojÀrjestelmÀ mukautuu nopeasti ÀÀniympÀristön vaihteluihin muun muassa hyödyntÀmÀllÀ aiempaa tietoa puheen sisÀllöstÀ tulkitessaan hÀiriöistÀ puhesignaalia
A methodological framework to distinguish spectrum effects from spectrum biases and to assess diagnostic and screening test accuracy for patient populations: Application to the Papanicolaou cervical cancer smear test
<p>Abstract</p> <p>Background</p> <p>A spectrum effect was defined as differences in the sensitivity or specificity of a diagnostic test according to the patient's characteristics or disease features. A spectrum effect can lead to a spectrum bias when subgroup variations in sensitivity or specificity also affect the likelihood ratios and thus post-test probabilities. We propose and illustrate a methodological framework to distinguish spectrum effects from spectrum biases.</p> <p>Methods</p> <p>Data were collected for 1781 women having had a cervical smear test and colposcopy followed by biopsy if abnormalities were detected (the reference standard). Logistic models were constructed to evaluate both the sensitivity and specificity, and the likelihood ratios, of the test and to identify factors independently affecting the test's characteristics.</p> <p>Results</p> <p>For both tests, human papillomavirus test, study setting and age affected sensitivity or specificity of the smear test (spectrum effect), but only human papillomavirus test and study setting modified the likelihood ratios (spectrum bias) for clinical reading, whereas only human papillomavirus test and age modified the likelihood ratios (spectrum bias) for "optimized" interpretation.</p> <p>Conclusion</p> <p>Fitting sensitivity, specificity and likelihood ratios simultaneously allows the identification of covariates that independently affect diagnostic or screening test results and distinguishes spectrum effect from spectrum bias. We recommend this approach for the development of new tests, and for reporting test accuracy for different patient populations.</p
Do ethnobotanical and laboratory data predict clinical safety and efficacy of anti-malarial plants?
<p>Abstract</p> <p>Background</p> <p>Over 1200 plant species are reported in ethnobotanical studies for the treatment of malaria and fevers, so it is important to prioritize plants for further development of anti-malarials.</p> <p>Methods</p> <p>The âRITAM scoreâ was designed to combine information from systematic literature searches of published ethnobotanical studies and laboratory pharmacological studies of efficacy and safety, in order to prioritize plants for further research. It was evaluated by correlating it with the results of clinical trials.</p> <p>Results and discussion</p> <p>The laboratory efficacy score correlated with clinical parasite clearance (r<sub>s</sub>=0.7). The ethnobotanical component correlated weakly with clinical symptom clearance but not with parasite clearance. The safety component was difficult to validate as all plants entering clinical trials were generally considered safe, so there was no clinical data on toxic plants.</p> <p>Conclusion</p> <p>The RITAM score (especially the efficacy and safety components) can be used as part of the selection process for prioritising plants for further research as anti-malarial drug candidates. The validation in this study was limited by the very small number of available clinical studies, and the heterogeneity of patients included.</p
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