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Existing indoor closed ultraviolet-C (UVC) air purifiers (UVC in a box) have faced technological challenges during the COVID-19 breakout, owing to demands of low energy consumption, high flow rates, and high kill rates at the same time. A new conceptual design of a novel UVC-LED (light-emitting diode) air purifier for a low-cost solution to mitigate airborne diseases is proposed. The concept focuses on performance and robustness. It contains a dust-filter assembly, an innovative UVC chamber, and a fan. The low-cost dust filter aims to suppress dust accumulation in the UVC chamber to ensure durability and is conceptually shown to be easily replaced while mitigating any possible contamination. The chamber includes novel turbulence-generating grids and a novel LED arrangement. The turbulent generator promotes air mixing, while the LEDs inactivate the pathogens at a high flow rate and sufficient kill rate. The conceptual design is portable and can fit into ventilation ducts. Computational fluid dynamics and UVC ray methods were used for analysis. The design produces a kill rate above 97% for COVID and tuberculosis and above 92% for influenza A at a flow rate of 100 L/s and power consumption of less than 300 W. An analysis of the dust-filter performance yields the irradiation and flow fields.

There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore, an analytical study was undertaken using published data to develop a psychrometric model to assess the biological decay rate of the virus in aerosols. This revealed that it is possible to describe with reasonable accuracy (R2 = 0.718, p < 0.001) the biological decay constant for the SARS-CoV-2 virus using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols outdoors was in the region 13-22 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. However, indoors, this variation is likely to be much less. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of SARS-CoV-2.

Purpose: To evaluate the relative importance and predictive ability of salivary immunoglobulin A (s-IgA) measures with regards to upper respiratory illness (URI) in youth athletes. Methods: Over a 38-week period, 22 youth athletes (age = 16.8 [0.5] y) provided daily symptoms of URI and 15 fortnightly passive drool saliva samples, from which s-IgA concentration and secretion rate were measured. Kernel-smoothed bootstrapping generated a balanced data set with simulated data points. The random forest algorithm was used to evaluate the relative importance (RI) and predictive ability of s-IgA concentration and secretion rate with regards to URI symptoms present on the day of saliva sampling (URIday), within 2 weeks of sampling (URI2wk), and within 4 weeks of sampling (URI4wk). Results: The percentage deviation from average healthy s-IgA concentration was the most important feature for URIday (median RI 1.74, interquartile range 1.41–2.07). The average healthy s-IgA secretion rate was the most important feature for URI4wk (median RI 0.94, interquartile range 0.79–1.13). No feature was clearly more important than any other when URI symptoms were identified within 2 weeks of sampling. The values for median area under the curve were 0.68, 0.63, and 0.65 for URIday, URI2wk, and URI4wk, respectively. Conclusions: The RI values suggest that the percentage deviation from average healthy s-IgA concentration may be used to evaluate the short-term risk of URI, while the average healthy s-IgA secretion rate may be used to evaluate the long-term risk. However, the results show that neither s-IgA concentration nor secretion rate can be used to accurately predict URI onset within a 4-week window in youth athletes.

OBJECTIVES: Acquiring central venous pressure (CVP), an important clinical parameter, requires an invasive procedure, which poses risk to patients. The aim of the study was to develop a non-invasive methodology for determining mean-CVP from ultrasound assessment of the jugular venous pulse. METHODS: In thirty-four adult patients (age = 60 ± 12 years; 10 males), CVP was measured using a central venous catheter, with internal jugular vein (IJV) cross-sectional area (CSA) variation along the cardiac beat acquired using ultrasound. The resultant CVP and IJV-CSA signals were synchronized with electrocardiogram (ECG) signals acquired from the patients. Autocorrelation signals were derived from the IJV-CSA signals using algorithms in R (open-source statistical software). The correlation r-values for successive lag intervals were extracted and used to build a linear regression model in which mean-CVP was the response variable and the lagging autocorrelation r-values and mean IJV-CSA, were the predictor variables. The optimum model was identified using the minimum AIC value and validated using 10-fold cross-validation. RESULTS: While the CVP and IJV-CSA signals were poorly correlated (mean r = -0.018, SD = 0.357) due to the IJV-CSA signal lagging behind the CVP signal, their autocorrelation counterparts were highly positively correlated (mean r = 0.725, SD = 0.215). Using the lagging autocorrelation r-values as predictors, mean-CVP was predicted with reasonable accuracy (r2 = 0.612), with a mean-absolute-error of 1.455 cmH2O, which rose to 2.436 cmH2O when cross-validation was performed. CONCLUSIONS: Mean-CVP can be estimated non-invasively by using the lagged autocorrelation r-values of the IJV-CSA signal. This new methodology may have considerable potential as a clinical monitoring and diagnostic tool.

As the world’s economies come out of the lockdown imposed by the COVID-19 pandemic, there is an urgent need for technologies to mitigate COVID-19 transmission in confined spaces such as buildings. This feasibility study looks at one such technology, upper-room ultraviolet (UV) air disinfection, that can be safely used while humans are present in the room space, and which has already proven its efficacy as an intervention to inhibit the transmission of airborne diseases such as measles and tuberculosis. Using published data from various sources, it is shown that the SARS-CoV-2 virus, the causative agent of COVID-19, is highly likely to be susceptible to UV-C damage when suspended in air, with a UV susceptibility constant likely to be in the region 0.377–0.590 m2/J, similar to that for other aerosolised coronaviruses. As such, the UV-C flux required to disinfect the virus is expected to be acceptable and safe for upper-room applications. Through analysis of expected and worst-case scenarios, the efficacy of the upper-room UV-C approach for reducing COVID-19 transmission in confined spaces (with moderate but sufficient ceiling height) is demonstrated. Furthermore, it is shown that with SARS-CoV-2, it should be possible to achieve high equivalent air change rates using upper-room UV air disinfection, suggesting that the technology might be particularly applicable to poorly ventilated spaces.

Purpose Despite being a widely used management technique, cumulative sum (CUSUM) analysis remains almost unheard of in professional sport. To address this, CUSUM analysis of soccer match data from the English Premier League (EPL) was performed. The primary objective of the study was to evaluate CUSUM as a tool for assessing ‘on-field’ team performance. As a secondary objective, the association between managerial change and team performance was evaluated. Design/methodology/approach CUSUM was applied retrospectively to goal difference data for six EPL teams (Arsenal, Chelsea, Everton, Liverpool, Manchester United, and Tottenham) over 23 consecutive seasons from 1995-2018. This was supplemented with change point analysis to identify structural changes in mean goal difference. Succession was evaluated by mapping historical managerial changes onto the CUSUM plots for the respective clubs. Findings CUSUM analysis revealed the presence of structural changes in four clubs. Two structural change points were identified for both Chelsea and Everton, one for Manchester United and Tottenham, and none for Arsenal and Liverpool. Relatively few managerial changes coincided temporally with structural changes in ‘on-field’ performance, with most appointments having minimal impact on long-term team performance. Other factors (e.g. changes in ownership) appear to have been influential. Research limitations/implications The study was limited by the fact that only successful teams were investigated. Practical implications CUSUM analysis appears to have potential as a tool for executive decision-makers to evaluate performance outcomes in professional soccer. Originality/value The study is the first of its kind to use CUSUM analysis to evaluate team performance in professional soccer.

Identifying the external training load variables which influence subjective internal response will help reduce the mismatch between coach-intended and athlete-perceived training intensity. Therefore, this study aimed to reduce external training load measures into distinct principal components (PCs), plot internal training response (quantified via session Rating of Perceived Exertion [sRPE]) against the identified PCs and investigate how the prescription of PCs influences subjective internal training response. Twenty-nine school to international level youth athletes wore microtechnology units for field-based training sessions. SRPE was collected post-session and assigned to the microtechnology unit data for the corresponding training session. 198 rugby union, 145 field hockey and 142 soccer observations were analysed. The external training variables were reduced to two PCs for each sport cumulatively explaining 91%, 96% and 91% of sRPE variance in rugby union, field hockey and soccer, respectively. However, when internal response was plotted against the PCs, the lack of separation between low-, moderate- and high-intensity training sessions precluded further analysis as the prescription of the PCs do not appear to distinguish subjective session intensity. A coach may therefore wish to consider the multitude of physiological, psychological and environmental factors which influence sRPE alongside external training load prescription.

The cerebrospinal fluid (CSF) pulse in the Aqueduct of Sylvius (aCSF pulse) is often used to evaluate structural changes in the brain. Here we present a novel application of the general linear model (GLM) to predict the motion of the aCSF pulse. MR venography was performed on 13 healthy adults (9 female and 4 males—mean age = 33.2 years). Flow data was acquired from the arterial, venous and CSF vessels in the neck (C2/C3 level) and from the AoS. Regression analysis was undertaken to predict the motion of the aCSF pulse using the cervical flow rates as predictor variables. The relative contribution of these variables to predicting aCSF flow rate was assessed using a relative weights method, coupled with an ANOVA. Analysis revealed that the aCSF pulse could be accurately predicted (mean (SD) adjusted r2 = 0.794 (0.184)) using the GLM (p < 0.01). Venous flow rate in the neck was the strongest predictor of aCSF pulse (p = 0.001). In healthy individuals, the motion of the aCSF pulse can be predicted using the GLM. This indicates that the intracranial fluidic system has broadly linear characteristics. Venous flow in the neck is the strongest predictor of the aCSF pulse.

The purpose of this study was to determine the importance of physical qualities for speed and change of direction (CoD) ability in female soccer players. Data were collected on 10 female soccer players who were part of a professional English Women’s Super League team. Player assessments included anthropometric (stature and body mass), body composition (dual-energy X-ray absorptiometry), speed (10m, 30m sprint), CoD ability (505 agility), aerobic (Yo-Yo Intermittent Recovery Test), lower-body strength (bilateral knee extensions) and power (countermovement jump [CMJ], squat jump [SJ], 30cm drop jump [DJ]) measures). The relationships between the variables were evaluated using eigenvector analysis and Pearson correlation analysis. Multiple linear regression revealed that the performance variables (10 and 20m speed, mean 505, and CoD deficit mean) can be predicted with almost 100% accuracy (i.e. adjusted R2 > 0.999) using various combinations of the predictor variables (DJ height, CMJ height, SJ height, lean body mass). An increase of one standard deviation (SD) in DJ height was associated with reductions of -5.636 and 9.082 SD in 10 m and 20 m sprint times. A one SD increase in CMJ also results in a reduction of -3.317 and -0.922 SD respectively in mean 505 and CoD deficit mean values. This study provides comparative data for professional English female soccer players that can be used by strength and conditioning coaches when monitoring player development and assessing the effectiveness of training programmes. Findings highlight the importance of developing reactive strength to improve speed and CoD ability in female soccer players.

Understanding the most demanding passages of European Super League competition can optimise training prescription. We established positional and match half differences in peak relative distances (m·min-1) across durations, and the number of collisions, high-speed- and very-high-speed-distance completed in the peak 10 min period. Moving-averages (10 s, 30 s, 1 min, 5 min, 10 min) of instantaneous speed (m·s-1) were calculated from 25 professional rugby league players during 25 matches via microtechnology. Maximal m·min-1 was taken for each duration for each half. Concurrently, collisions (n), high-speed- (5 to 7 m·s-1; m) and very-high-speed-distance (> 7 m·s-1; m) were coded during each peak 10 min. Mixed-effects models determined differences between positions and halves. Aside from peak 10 s, trivial differences were observed in peak m·min-1 between positions or halves across durations. During peak 10 min periods, adjustables, full- and outside-backs ran more at high-speed and very-high-speed whilst middle- and edge-forwards completed more collisions. Peak m·min-1 is similar between positional groups across a range of durations and are maintained between halves of the match. Practitioners should consider that whilst the overall peak locomotor "intensity" is similar, how they achieve this differs between positions with forwards also exposed to additional collision bouts.

The skeleton of a cricket fast bowler is exposed to a unique combination of gravitational and torsional loading in the form of substantial ground reaction forces delivered through the front landing foot, and anterior-posterior shear forces mediated by regional muscle contractions across the lumbo-pelvic region. The objectives of this study were to compare the hip structural characteristics of elite fast bowlers with recreationally-active age-matched controls, and to examine unilateral bone properties in fast bowlers. Dual-energy X-ray absorptiometry (DXA) of the proximal femur was performed in 26 elite male fast bowlers and 26 normally-active controls. Hip structural analysis (GE Lunar; enCORE version 15.0) determined areal bone mineral density (BMD) of the proximal femur, and cross-sectional area (CSA), section modulus (Z), cross-sectional moment of inertia (CSMI) and femoral strength index (FSI) at the narrow region of the femoral neck. Mean femoral neck and trochanter BMD were greater in fast bowlers than controls (p < 0.001). All bone geometry properties except for CSMI were superior in fast bowlers (p < 0.05) following adjustment for height and lean mass. There were no asymmetries in BMD or bone geometry when considering leg dominance of the fast bowlers (p > 0.05). Elite fast bowlers have superior bone characteristics of the proximal femur, with results inferring enhanced resistance to axial compression (CSA), and bending (Z) forces, and enhanced strength to withstand a fall impact as indicated by their higher FSI. No asymmetries in hip bone properties were identified, suggesting that both torsional and gravitational loading offer significant osteogenic potential.

Objectives Multiple sclerosis (MS) patients frequently suffer from headaches and fatigue, and many reports have linked headaches with intracranial and/or extracranial venous obstruction. We therefore designed a study involving MS patients diagnosed with obstructive disease of internal jugular veins (IJVs), with the aim of evaluating the impact of percutaneous transluminal angioplasty (PTA) on headache and fatigue indicators. Methods 286 MS patients (175 relapsing remitting (RR), 75 secondary progressive (SP), and 36 primary progressive (PP)), diagnosed with obstructive disease of IJVs, underwent PTA of IJVs during the period 2011–2015. This included 113 headache positive patients (82 RR, 22 SP, and 9 PP) and 277 fatigue positive patients (167 RR, 74 SP, and 36 PP). Migraine Disability Assessment (MIDAS), and the Fatigue Severity Scale (FSS) were evaluated: before PTA; 3-months after PTA; and at final follow-up in 2017. Patients were evaluated with Doppler sonography of the IJVs at 1, 6 and 12 months after PTA and yearly thereafter. Non-parametric statistical analysis was performed using a combination of the Friedman test and Spearman correlation analysis. Results With the exception of the PP patients there were significant reductions (all p < 0.001) in the MIDAS and FSS scores in the 3-month following PTA. The improvement in MIDAS score following PTA was maintained throughout the follow-up period in both the RR (p < 0.001; mean of 3.55 years) and SP (p = 0.002; mean of 3.52 years) MS cohorts. With FSS, significant improvement was only observed at 2017 follow-up in the RR patients (p < 0.001; mean of 3.37 years). In the headache-positive patients, post-PTA MIDAS score was significantly negatively correlated with the change in the blood flow score in the left (r = -0.238, p = 0.031) and right (r = -0.250, p = 0.023) IJVs in the RR patients and left IJV (r = -0.727, p = 0.026) in the PP patients. In the fatigue-positive cohort, post-PTA FSS score was also significantly

PURPOSE: Adductor longus injuries are complex. The conflict between views in the recent literature and various nineteenth-century anatomy books regarding symphyseal and perisymphyseal anatomy can lead to difficulties in MRI interpretation and treatment decisions. The aim of the study is to systematically investigate the pyramidalis muscle and its anatomical connections with adductor longus and rectus abdominis, to elucidate injury patterns occurring with adductor avulsions. METHODS: A layered dissection of the soft tissues of the anterior symphyseal area was performed on seven fresh-frozen male cadavers. The dimensions of the pyramidalis muscle were measured and anatomical connections with adductor longus, rectus abdominis and aponeuroses examined. RESULTS: The pyramidalis is the only abdominal muscle anterior to the pubic bone and was found bilaterally in all specimens. It arises from the pubic crest and anterior pubic ligament and attaches to the linea alba on the medial border. The proximal adductor longus attaches to the pubic crest and anterior pubic ligament. The anterior pubic ligament is also a fascial anchor point connecting the lower anterior abdominal aponeurosis and fascia lata. The rectus abdominis, however, is not attached to the adductor longus; its lateral tendon attaches to the cranial border of the pubis; and its slender internal tendon attaches inferiorly to the symphysis with fascia lata and gracilis. CONCLUSION: The study demonstrates a strong direct connection between the pyramidalis muscle and adductor longus tendon via the anterior pubic ligament, and it introduces the new anatomical concept of the pyramidalis-anterior pubic ligament-adductor longus complex (PLAC). Knowledge of these anatomical relationships should be employed to aid in image interpretation and treatment planning with proximal adductor avulsions. In particular, MRI imaging should be employed for all proximal adductor longus avulsions to assess the integrity of the PLAC.

The purpose of this study was to determine the importance of physical qualities for speed and change of direction (CoD) ability in female soccer players. Data were collected on 10 female soccer players who were part of a professional English Women’s Super League team. Player assessments included anthropometric (stature and body mass), body composition (dual-energy X-ray absorptiometry), speed (10m, 30m sprint), CoD ability (505 agility), aerobic (Yo-Yo Intermittent Recovery Test), lower-body strength (bilateral knee extensions) and power (countermovement jump [CMJ], squat jump [SJ], 30cm drop jump [DJ]) measures). The relationships between the variables were evaluated using eigenvector analysis and Pearson correlation analysis. Multiple linear regression revealed that the performance variables (10 and 20m speed, mean 505, and CoD deficit mean) can be predicted with almost 100% accuracy (i.e. adjusted R2 > 0.999) using various combinations of the predictor variables (DJ height, CMJ height, SJ height, lean body mass). An increase of one standard deviation (SD) in DJ height was associated with reductions of -5.636 and 9.082 SD in 10 m and 20 m sprint times. A one SD increase in CMJ also results in a reduction of -3.317 and -0.922 SD respectively in mean 505 and CoD deficit mean values. This study provides comparative data for professional English female soccer players that can be used by strength and conditioning coaches when monitoring player development and assessing the effectiveness of training programmes. Findings highlight the importance of developing reactive strength to improve speed and CoD ability in female soccer players.

Objectives: To retrospectively compare the longitudinal physical development of junior rugby league players between the Under 13 and 15 age categories in relation to their adult career attainment outcome.Design: Retrospective longitudinal design.Methods: Fifty-one former junior rugby league players were retrospectively grouped according to their career attainment outcome as adults (i.e., amateur, academy or professional). As juniors, players under-took a physical testing battery on three consecutive annual occasions (Under 13s, 14s, 15s) including height, body mass, sum of four skinfolds, maturation, vertical jump, medicine ball chest throw, 10–60 msprint, agility 505 and estimated VO2max. Results: Future professional players were younger than academy players with a greater estimated˙VO2max compared to amateur players. Between Under 13s and 15s, professional players (5.8 ± 2.5 cm) increased sitting height more than amateur (4.4 ± 2.1 cm) and academy (4.1 ± 1.4 cm) players. Logistic regression analyses demonstrated improvements in sitting height, 60 m sprint, agility 505 and estimated˙VO2max between amateur and professional players with a high degree of accuracy (sensitivity = 86.7%, specificity = 91.7%). Conclusions: Findings demonstrate that the development of anthropometric, maturational and physical qualities in junior rugby league players aged between 13 and 15 years contributed to adulthood career attainment outcomes. Results suggest that age, maturity and size advantages, commonly observed in adolescent focused talent identification research and practice, may not be sensitive to changes in later stages of development in order to correctly identify career attainment. Practitioners should identify, monitor and develop physical qualities of adolescent rugby league players with long-term athlete development in mind.

Ranking enables coaches, sporting authorities, and pundits to determine the relative performance of individual athletes and teams in comparison to their peers. While ranking is relatively straightforward in sports that employ traditional leagues, it is more difficult in sports where competition is fragmented (e.g. athletics, boxing, etc.), with not all competitors competing against each other. In such situations, complex points systems are often employed to rank athletes. However, these systems have the inherent weakness that they frequently rely on subjective assessments in order to gauge the calibre of the competitors involved. Here we show how two Internet derived algorithms, the PageRank (PR) and user preference (UP) algorithms, when utilised with a simple ‘who beat who’ matrix, can be used to accurately rank track athletes, avoiding the need for subjective assessment. We applied the PR and UP algorithms to the 2015 IAAF Diamond League men’s 100m competition and compared their performance with the Keener, Colley and Massey ranking algorithms. The top five places computed by the PR and UP algorithms, and the Diamond League ‘2016’ points system were all identical, with the Kendall’s tau distance between the PR standings and ‘2016’ points system standings being just 15, indicating that only 5.9% of pairs differed in their order between these two lists. By comparison, the UP and ‘2016’ standings displayed a less strong relationship, with a tau distance of 95, indicating that 37.6% of the pairs differed in their order. When compared with the standings produced using the Keener, Colley and Massey algorithms, the PR standings appeared to be closest to the Keener standings (tau distance = 67, 26.5% pair order disagreement), whereas the UP standings were more similar to the Colley and Massey standings, with the tau distances between these ranking lists being only 48 (19.0% pair order disagreement) and 59 (23.3% pair order disagreement) respectively. In particular, the UP

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Prediction of adult performance from early age talent identification in sport remains difficult. Talent identification research has generally been performed using univariate analysis, which ignores multivariate relationships. To address this issue, this study used a novel higher-dimensional model to orthogonalize multivariate anthropometric and fitness data from junior rugby league players, with the aim of differentiating future career attainment. Anthropometric and fitness data from 257 Under-15 rugby league players was collected. Players were grouped retrospectively according to their future career attainment (i.e., amateur, academy, professional). Players were blindly and randomly divided into an exploratory (n = 165) and validation dataset (n = 92). The exploratory dataset was used to develop and optimize a novel higher-dimensional model, which combined singular value decomposition (SVD) with receiver operating characteristic analysis. Once optimized, the model was tested using the validation dataset. SVD analysis revealed 60 m sprint and agility 505 performance were the most influential characteristics in distinguishing future professional players from amateur and academy players. The exploratory dataset model was able to distinguish between future amateur and professional players with a high degree of accuracy (sensitivity = 85.7%, specificity = 71.1%; p<0.001), although it could not distinguish between future professional and academy players. The validation dataset model was able to distinguish future professionals from the rest with reasonable accuracy (sensitivity = 83.3%, specificity = 63.8%; p = 0.003). Through the use of SVD analysis it was possible to objectively identify criteria to distinguish future career attainment with a sensitivity over 80% using anthropometric and fitness data alone. As such, this suggests that SVD analysis may be a useful analysis tool for research and practice within talent identification.

Objectives Constricted cerebral venous outflow has been linked with increased cerebrospinal fluid (CSF) pulsatility in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy individuals. This study investigates the relationship between CSF pulsatility and internal jugular vein (IJV) cross-sectional area (CSA) in these two groups, something previously unknown. Methods 65 relapsing-remitting MS patients (50.8% female; mean age = 43.8 years) and 74 healthy controls (HCs) (54.1% female; mean age = 43.9 years) were investigated. CSF flow quantification was performed on cine phase-contrast MRI, while IJV-CSA was calculated using magnetic resonance venography. Statistical analysis involved correlation, and partial least squares correlation analysis (PLSCA). Results PLSCA revealed a significant difference (p<0.001; effect size = 1.072) between MS patients and HCs in the positive relationship between CSF pulsatility and IJV-CSA at C5-T1, something not detected at C2-C4. Controlling for age and cardiovascular risk factors, statistical trends were identified in HCs between: increased net positive CSF flow (NPF) and increased IJV-CSA at C5-C6 (left: r = 0.374, p = 0.016; right: r = 0.364, p = 0.019) and C4 (left: r = 0.361, p = 0.020); and increased net negative CSF flow and increased left IJV-CSA at C5-C6 (r = -0.348, p = 0.026) and C4 (r = -0.324, p = 0.039), whereas in MS patients a trend was only identified between increased NPF and increased left IJV-CSA at C5-C6 (r = 0.351, p = 0.021). Overall, correlations were weaker in MS patients (p = 0.015). Conclusions In healthy adults, increased CSF pulsatility is associated with increased IJV-CSA in the lower cervix (independent of age and cardiovascular risk factors), suggesting a biomechanical link between the two. This relationship is altered in MS patients.

Internal jugular vein (IJV) narrowing has been implicated in central nervous system pathologies, however normal physiological age- and gender-related IJV variance in healthy individuals (HIs) has not been adequately assessed.We assessed the relationship between IJV cross-sectional area (CSA) and aging.This study involved 193 HIs (63 males and 130 females) who received 2-dimensional magnetic resonance venography at 3T. The minimum CSA of the IJVs at cervical levels C2/C3, C4, C5/C6, and C7/T1 was obtained using a semi-automated contouring-thresholding technique. Subjects were grouped by decade. Pearson and partial correlation (controlled for cardiovascular risk factors, including hypertension, heart disease, smoking and body mass index) and analysis of variance analyses were used, with paired t-tests comparing side differences.Mean right IJV CSA ranges were: in males, 41.6 mm2 (C2/C3) to 82.0 mm2 (C7/T1); in females, 38.0 mm2 (C2/C3) to 62.3 mm2 (C7/T1), while the equivalent left side ranges were: in males, 28.0 mm2 (C2/C3) to 52.2 mm2 (C7/T1); in females, 27.2 mm2 (C2/C3) to 47.8 mm2 (C7/T1). The CSA of the right IJVs was significantly larger (p<0.001) than the left at all cervical levels. Controlling for cardiovascular risk factors, the correlation between age and IJV CSA was more robust in males than in the females for all cervical levels.In HIs age, gender, hand side and cervical location all affect IJV CSA. These findings suggest that any definition of IJV stenosis needs to account for these factors.

Objectives To assess the relationship between cross-sectional area of internal jugular veins and brain volumes in healthy individuals without neurologic disease. Methods A total of 193 healthy individuals without neurologic disease (63 male and 130 female; age > 20 to < 70 years) received magnetic resonance venography and structural brain magnetic resonance imaging at 3T. The internal jugular vein cross-sectional area was assessed at C2–C3, C4, C5–C6, and C7–T1. Normalized whole brain volume was assessed. Partial correlation analyses were used to determine associations. Results There was an inverse relationship between normalized whole brain volume and total internal jugular vein cross-sectional area (C7–T1: males r = −0.346, p = 0.029; females r = −0.301, p = 0.002). After age adjustment, association of normalized whole brain volume and normalized gray matter volume with internal jugular vein cross-sectional area became positive in males (normalized whole brain volume and right internal jugular vein cross-sectional area (C2–C3) changed from r = −0.163 to r = 0.384, p = 0.002), but not in the females. Conclusion Sex differences exist in the relationship between brain volume and internal jugular vein cross-sectional area in healthy individuals without neurologic disease.

This study examined the relationship between accelerometer metrics and both collisions and running demands during rugby union match-play. Twelve under-18 forwards and 14 under-18 backs were recruited from a professional rugby union club. Six competitive matches were filmed during which players wore micro-technological units (Optimeye S5, Catapult Innovations, Melbourne, Australia). Video footage was analysed for total collisions, while GPS data was analysed for total distance. Accelerometer metrics analysed were Player loadTM (PL), Player LoadTM 2D (PL2D), and Player LoadTM slow (PLslow). A total of 81 player observations were included in the final analysis. Data were analysed using ordinary least squares regression. A 10-fold cross validation analysis was used to validate the findings. All PL variables demonstrated very large relationships with collisions in the forwards, while PLslow demonstrated the largest relationship (large) with collisions in the backs. Therefore, based on the strong relationship in both forwards and backs, PLslow may provide the most useful metric for measuring collision-based activity in both positional groups during match-play. Additionally, nearly perfect and very large relationships were observed between PL and total distance for forwards and backs respectively, suggesting that PL can be successfully used to quantify running demands when other methods are unavailable, for example during indoor training.

Due to the focus of research within athletic populations, little is known about the hydration strategies of rugby league referees. We observed all 8 full-time professional referees, during 31 Super League matches to investigate the drinking strategies and magnitude of dehydration (body mass loss) experienced by referees during match play. Referees arrived and remained euhydrated (urine osmolality; pre and post-match 558 ± 310 and 466 ± 283 mOsmol•kg-1). Mean body mass change was -0.7 ± 0.8%, fluid loss was 890 ± 435 g and fluid intake was 444 ± 167, 438 ± 190, 254 ± 108 and 471 ± 221 g during pre-match, first-half, half-time and second-half. This study suggests elite referees adopt appropriate hydration strategies during match-play to prevent large reductions in body mass, although individual variability was observed. Future research should investigate dehydration in referees from other sports and the effects on refereeing performance.

There is an ongoing debate about the reasons for and factors contributing to healthcare-associated infection (HAI). Different solutions have been proposed over time to control the spread of HAI, with more focus on hand hygiene than on other aspects such as preventing the aerial dissemination of bacteria. Yet, it emerges that there is a need for a more pluralistic approach to infection control; one that reflects the complexity of the systems associated with HAI and involves multidisciplinary teams including hospital doctors, infection control nurses, microbiologists, architects, and engineers with expertise in building design and facilities management. This study reviews the knowledge base on the role that environmental contamination plays in the transmission of HAI, with the aim of raising awareness regarding infection control issues that are frequently overlooked. From the discussion presented in the study, it is clear that many unknowns persist regarding aerial dissemination of bacteria, and its control via cleaning and disinfection of the clinical environment. There is a paucity of good-quality epidemiological data, making it difficult for healthcare authorities to develop evidence-based policies. Consequently, there is a strong need for carefully designed studies to determine the impact of environmental contamination on the spread of HAI.

The use of electroencephalograms (EEGs) to diagnose and analyses Alzheimer’s disease (AD) has received much attention in recent years. The sample entropy (SE) has been widely applied to the diagnosis of AD. In our study, nine EEGs from 21 scalp electrodes in 3 AD patients and 9 EEGs from 3 age-matched controls are recorded. The calculations show that the kurtoses of the AD patients’ EEG are positive and much higher than that of the controls. This finding encourages us to introduce a kurtosis-based de-noising method. The 21-electrode EEG is first decomposed using independent component analysis (ICA), and second sort them using their kurtoses in ascending order. Finally, the subspace of EEG signal using back projection of only the last five components is reconstructed. SE will be calculated after the above de-noising preprocess. The classifications show that this method can significantly improve the accuracy of SE-based diagnosis. The kurtosis analysis of EEG may contribute to increasing the understanding of brain dysfunction in AD in a statistical way.

OBJECTIVE: While chronic cerebrospinal venous insufficiency (CCSVI) can be characterized using cervical plethysmography, much remains unknown about the haemodynamics associated with this procedure. The aim of the study was therefore to gain a deeper understanding of the observed haemodynamics. METHOD: Forty healthy controls and 44 CCSVI patients underwent cervical plethysmography, which involved placing a strain-gauge collar around their necks and tipping them from the upright (90(o)) to supine position (0(o)) in a chair. Once stabilized, they were returned to the upright position, allowing blood to drain from the neck. A mathematical model was used to calculate the hydraulic resistance of the extracranial venous system for each subject in the study. RESULTS: The mean hydraulic resistance of the extracranial venous system was 10.28 (standard deviation [SD] 5.14) mmHg.s/mL in the healthy controls and 16.81 (SD 9.22) in the CCSVI patients (P < 0.001). CONCLUSIONS: The haemodynamics of the extracranial venous system are greatly altered in CCSVI patients.

To determine whether jugular venous reflux (JVR) is associated with cerebral white matter changes (WMCs) in individuals with Alzheimer's disease (AD), we studied 12 AD patients 24 mild cognitive impairment (MCI) patients, and 17 elderly age- and gender-matched controls. Duplex ultrasonography and 1.5T MRI scanning was applied to quantify cerebral WMCs [T2 white matter (WM) lesion and dirty-appearing-white-matter (DAWM)]. Subjects with severe JVR had more frequently hypertension (p = 0.044), more severe WMC, including increased total (p = 0.047) and periventricular DAWM volumes (p = 0.008), and a trend for increased cerebrospinal fluid volumes (p = 0.067) compared with the other groups. A significantly decreased (65.8%) periventricular DAWM volume (p = 0.01) in the JVR-positive AD individuals compared with their JVR-negative counterparts was detected. There was a trend for increased periventricular and subcortical T2 WMC lesion volumes in the JVR-positive AD individuals compared with their JVR-negative counterparts (p = 0.073). This phenomenon was not observed in either the control or MCI groups. In multiple regression analysis, the increased periventricular WMC lesion volume and decreased DAWM volume resulted in 85.7% sensitivity and 80% specificity for distinguishing between JVR-positive and JVR-negative AD patients. These JVR-WMC association patterns were not seen in the control and MCI groups. Therefore, this pilot study suggests that there may be an association between JVR and WMCs in AD patients, implying that cerebral venous outflow impairment might play a role in the dynamics of WMCs formation in AD patients, particularly in the periventricular regions. Further longitudinal studies are needed to confirm and validate our findings.

In this review, the impact of restricted cere- bral venous outflow on the biomechanics of the intracranial fluid system is investigated. The cerebral venous drainage system is often viewed simply as a series of collecting vessels channeling blood back to the heart. However there is growing evidence that it plays an important role in regulating the intracranial fluid system. In particular, there appears to be a link between increased cerebrospinal fluid (CSF) pulsatility in the Aqueduct of Sylvius and constricted venous outflow. Constricted venous outflow also appears to inhibit absorp- tion of CSF into the superior sagittal sinus. The compliance of the cortical bridging veins appears to be critical to the behaviour of the intracranial fluid system, with abnormalities at this location implicated in normal pressure hydrocephalus. The compliance associated with these vessels appears to be functional in nature and dependent on the free egress of blood out of the cranium via the extracranial venous drainage pathways. Because constrict- ed venous outflow appears to be linked with increased aqueductal CSF pulsatility, it sug- gests that inhibited venous blood outflow may be altering the compliance of the cortical bridging veins.

BACKGROUND: In this paper we use multivariate statistical techniques to gain insights into how adaptive gait involving obstacle crossing is regulated in lower-limb amputees compared to able-bodied controls, with the aim of identifying underlying characteristics that differ between the two groups and consequently highlighting gait deficits in the amputees. METHODS: Eight unilateral trans-tibial amputees and twelve able-bodied controls completed adaptive gait trials involving negotiating various height obstacles; with amputees leading with their prosthetic limb. Spatiotemporal variables that are regularly used to quantify how gait is adapted when crossing obstacles were determined and subsequently analysed using multivariate statistical techniques. RESULTS AND DISCUSSION: There were fundamental differences in the adaptive gait between the two groups. Compared to controls, amputees had a reduced approach velocity, reduced foot placement distance before and after the obstacle and reduced foot clearance over it, and reduced lead-limb knee flexion during the step following crossing. Logistic regression analysis highlighted the variables that best distinguished between the gait of the two groups and multiple regression analysis (with approach velocity as a controlling factor) helped identify what gait adaptations were driving the differences seen in these variables. Getting closer to the obstacle before crossing it appeared to be a strategy to ensure the heel of the lead-limb foot passed over the obstacle prior to the foot being lowered to the ground. Despite adopting such a heel clearance strategy, the lead-foot was positioned closer to the obstacle following crossing, which was likely a result of a desire to attain a limb/foot angle and orientation at instant of landing that minimised loads on the residuum (as evidenced by the reduced lead-limb knee flexion during the step following crossing). These changes in foot placement meant the foot was in a different part of swin

BACKGROUND: To determine whether or not jugular venous reflux (JVR) is associated with structural brain parenchyma changes in individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS: 16 AD patients (mean (SD): 81.9 (5.8) years), 33 MCI patients (mean (SD): 81.4 (6.1) years) and 18 healthy elderly controls (mean (SD): 81.5 (3.4) years) underwent duplex ultrasonography and magnetic resonance imaging scans to quantify structural brain parenchyma changes. Normalized whole brain (WB), gray matter (GM) and white matter (WM) volumes were collected, together with CSF volume. RESULTS: JVR was strongly associated with increased normalized WB (p = 0.014) and GM (p = 0.002) volumes across all three subject groups. There was a trend towards increased WB and GM volumes, which was accompanied by decreased CSF volume, in the JVR-positive subjects in both the MCI and AD groups. When the MCI and AD subjects were aggregated together significant increases were observed in both normalized WB (p = 0.009) and GM (p = 0.003) volumes for the JVR-positive group. No corresponding increases were observed for the JVR-positive subjects in the control group. Through receiver operating characteristic analysis of the brain volumetric data it was possible to discriminate between the JVR-positive and negative AD subjects with reasonable accuracy (sensitivity = 71.4%; specificity = 88.9%; p = 0.007). CONCLUSIONS: JVR is associated with intracranial structural changes in MCI and AD patients, which result in increased WB and GM volumes. The neuropathology of this unexpected and counterintuitive finding requires further investigation, but may suggest that JVR retrogradely transmits venous hypertension into the brain and leads to brain tissues swelling due to vasogenic edema.

Venous abnormalities contribute to the pathophysiology of several neurological conditions. This paper reviews the literature regarding venous abnormalities in multiple sclerosis (MS), leukoaraiosis, and normal-pressure hydrocephalus (NPH). The review is supplemented with hydrodynamic analysis to assess the effects on cerebrospinal fluid (CSF) dynamics and cerebral blood flow (CBF) of venous hypertension in general, and chronic cerebrospinal venous insufficiency (CCSVI) in particular.CCSVI-like venous anomalies seem unlikely to account for reduced CBF in patients with MS, thus other mechanisms must be at work, which increase the hydraulic resistance of the cerebral vascular bed in MS. Similarly, hydrodynamic changes appear to be responsible for reduced CBF in leukoaraiosis. The hydrodynamic properties of the periventricular veins make these vessels particularly vulnerable to ischemia and plaque formation.Venous hypertension in the dural sinuses can alter intracranial compliance. Consequently, venous hypertension may change the CSF dynamics, affecting the intracranial windkessel mechanism. MS and NPH appear to share some similar characteristics, with both conditions exhibiting increased CSF pulsatility in the aqueduct of Sylvius.CCSVI appears to be a real phenomenon associated with MS, which causes venous hypertension in the dural sinuses. However, the role of CCSVI in the pathophysiology of MS remains unclear.

BACKGROUND: The potential pathogenesis between the presence and severity of chronic cerebrospinal venous insufficiency (CCSVI) and its relation to clinical and imaging outcomes in brain parenchyma of multiple sclerosis (MS) patients has not yet been elucidated. The aim of the study was to investigate the relationship between CCSVI, and altered brain parenchyma venous vasculature visibility (VVV) on susceptibility-weighted imaging (SWI) in patients with MS and in sex- and age-matched healthy controls (HC). METHODS: 59 MS patients, 41 relapsing-remitting and 18 secondary-progressive, and 33 HC were imaged on a 3T GE scanner using pre- and post-contrast SWI venography. The presence and severity of CCSVI was determined using extra-cranial and trans-cranial Doppler criteria. Apparent total venous volume (ATVV), venous intracranial fraction (VIF) and average distance-from-vein (DFV) were calculated for various vein mean diameter categories: < .3 mm, .3-.6 mm, .6-.9 mm and > .9 mm. RESULTS: CCSVI criteria were fulfilled in 79.7% of MS patients and 18.2% of HC (p < .0001). Patients with MS showed decreased overall ATVV, ATVV of veins with a diameter < .3 mm, and increased DFV compared to HC (all p < .0001). Subjects diagnosed with CCSVI had significantly increased DFV (p < .0001), decreased overall ATVV and ATVV of veins with a diameter < .3 mm (p < .003) compared to subjects without CCSVI. The severity of CCSVI was significantly related to decreased VVV in MS (p < .0001) on pre- and post-contrast SWI, but not in HC. CONCLUSIONS: MS patients with higher number of venous stenoses, indicative of CCSVI severity, showed significantly decreased venous vasculature in the brain parenchyma. The pathogenesis of these findings has to be further investigated, but they suggest that reduced metabolism and morphological changes of venous vasculature may be taking place in patients with MS.

BACKGROUND: Although many infections that are transmissible from person to person are acquired through direct contact between individuals, a minority, notably pulmonary tuberculosis (TB), measles and influenza are known to be spread by the airborne route. Airborne infections pose a particular threat to susceptible individuals whenever they are placed together with the index case in confined spaces. With this in mind, waiting areas of healthcare facilities present a particular challenge, since large numbers of people, some of whom may have underlying conditions which predispose them to infection, congregate in such spaces and can be exposed to an individual who may be shedding potentially pathogenic microorganisms. It is therefore important to understand the risks posed by infectious individuals in waiting areas, so that interventions can be developed to minimise the spread of airborne infections. METHOD: A stochastic Monte Carlo model was constructed to analyse the transmission of airborne infection in a hypothetical 132 m3 hospital waiting area in which occupancy levels, waiting times and ventilation rate can all be varied. In the model the Gammaitoni-Nucci equation was utilized to predict probability of susceptible individuals becoming infected. The model was used to assess the risk of transmission of three infectious diseases, TB, influenza and measles. In order to allow for stochasticity a random number generator was applied to the variables in the model and a total of 10000 individual simulations were undertaken. The mean quanta production rates used in the study were 12.7, 100 and 570 per hour for TB, influenza and measles, respectively. RESULTS: The results of the study revealed the mean probability of acquiring a TB infection during a 30-minute stay in the waiting area to be negligible (i.e. 0.0034), while that for influenza was an order of magnitude higher at 0.0262. By comparison the mean probability of acquiring a measles infection during the same period

BACKGROUND: In recent years there has been renewed interest in the use of air ionizers to control the spread of infection in hospitals and a number of researchers have investigated the biocidal action of ions in both air and nitrogen. By comparison, the physical action of air ions on bacterial dissemination and deposition has largely been ignored. However, there is clinical evidence that air ions might play an important role in preventing the transmission of Acinetobacter infection. Although the reasons for this are unclear, it is hypothesized that a physical effect may be responsible: the production of air ions may negatively charge items of plastic medical equipment so that they repel, rather than attract, airborne bacteria. By negatively charging both particles in the air and items of plastic equipment, the ionizers minimize electrostatic deposition on these items. In so doing they may help to interrupt the transmission of Acinetobacter infection in certain healthcare settings such as intensive care units. METHODS: A study was undertaken in a mechanically ventilated room under ambient conditions to accurately measure changes in surface potential exhibited by items of plastic medical equipment in the presence of negative air ions. Plastic items were suspended on nylon threads, either in free space or in contact with a table surface, and exposed to negative ions produced by an air ionizer. The charge build-up on the specimens was measured using an electric field mill while the ion concentration in the room air was recorded using a portable ion counter. RESULTS: The results of the study demonstrated that common items of equipment such as ventilator tubes rapidly developed a large negative charge (i.e. generally >-100V) in the presence of a negative air ionizer. While most items of equipment tested behaved in a similar manner to this, one item, a box from a urological collection and monitoring system (the only item made from styrene acrylonitrile), did however develo

BACKGROUND: Good hand hygiene has for many years been considered to be the most important measure that can be applied to prevent the spread of healthcare-associated infection (HAI). Continuous emphasis on this intervention has lead to the widespread opinion that HAI rates can be greatly reduced by increased hand hygiene compliance alone. However, this assumes that the effectiveness of hand hygiene is not constrained by other factors and that improved compliance in excess of a given level, in itself, will result in a commensurate reduction in the incidence of HAI. However, there is evidence that the law of diminishing returns applies to hand hygiene, with the greatest benefits occurring in the first 20% or so of compliance. While this raises intriguing questions about the extent to which increasing compliance alone can further reduce rates of HAI, analysis of this subject has been hampered by a lack of quantifiable data relating to the risk of transmission between patients on wards. METHODS: In order to gain a greater understanding of the transmission of infection between patients via the hands of healthcare workers (HCWs), we constructed a stochastic Monte Carlo model to simulate the spread of methicillin-resistant Staphylococcus aureus (MRSA) between patients. We used the model to calculate the risk of transmission occurring, firstly between two patients in adjacent beds, and then between patients in a four-bedded bay. The aim of the study was to quantify the probability of transmission under a variety of conditions and thus to gain an understanding of the contribution made by the various factors which influence transmission. RESULTS: The study revealed that on a four-bedded bay, the average probability of transmitting an infection by the handborne route is generally low (i.e. in the region 0.002 - 0.013 depending on the hand hygiene behaviour of HCWs and other factors). However, because transmission is strongly influenced by stochastic events, it is the frequency

BACKGROUND: Hand hygiene is generally considered to be the most important measure that can be applied to prevent the spread of healthcare-associated infection (HAI). Continuous emphasis on this intervention has lead to the widespread opinion that HAI rates can be greatly reduced by increased hand hygiene compliance alone. However, this assumes that the effectiveness of hand hygiene is not constrained by other factors and that improved compliance in excess of a given level, in itself, will result in a commensurate reduction in the incidence of HAI. However, several researchers have found the law of diminishing returns to apply to hand hygiene, with the greatest benefits occurring in the first 20% or so of compliance, and others have demonstrated that poor cohorting of nursing staff profoundly influences the effectiveness of hand hygiene measures. Collectively, these findings raise intriguing questions about the extent to which increasing compliance alone can further reduce rates of HAI. METHODS: In order to investigate these issues further, we constructed a deterministic Ross-Macdonald model and applied it to a hypothetical general medical ward. In this model the transmission of staphylococcal infection was assumed to occur after contact with the transiently colonized hands of HCWs, who, in turn, acquire contamination only by touching colonized patients. The aim of the study was to evaluate the impact of imperfect hand cleansing on the transmission of staphylococcal infection and to identify, whether there is a limit, above which further hand hygiene compliance is unlikely to be of benefit. RESULTS: The model demonstrated that if transmission is solely via the hands of HCWs, it should, under most circumstances, be possible to prevent outbreaks of staphylococcal infection from occurring at a hand cleansing frequencies < 50%, even with imperfect hand hygiene. The analysis also indicated that the relationship between hand cleansing efficacy and frequency is not linear

BACKGROUND: Clostridium difficile-associated diarrhoea (CDAD) is a frequently occurring healthcare-associated infection, which is responsible for significant morbidity and mortality amongst elderly patients in healthcare facilities. Environmental contamination is known to play an important contributory role in the spread of CDAD and it is suspected that contamination might be occurring as a result of aerial dissemination of C. difficile spores. However previous studies have failed to isolate C. difficile from air in hospitals. In an attempt to clarify this issue we undertook a short controlled pilot study in an elderly care ward with the aim of culturing C. difficile from the air. METHODS: In a survey undertaken during February (two days) 2006 and March (two days) 2007, air samples were collected using a portable cyclone sampler and surface samples collected using contact plates in a UK hospital. Sampling took place in a six bedded elderly care bay (Study) during February 2006 and in March 2007 both the study bay and a four bedded orthopaedic bay (Control). Particulate material from the air was collected in Ringer's solution, alcohol shocked and plated out in triplicate onto Brazier's CCEY agar without egg yolk, but supplemented with 5 mg/L of lysozyme. After incubation, the identity of isolates was confirmed by standard techniques. Ribotyping and REP-PCR fingerprinting were used to further characterise isolates. RESULTS: On both days in February 2006, C. difficile was cultured from the air with 23 samples yielding the bacterium (mean counts 53 - 426 cfu/m3 of air). One representative isolate from each of these was characterized further. Of the 23 isolates, 22 were ribotype 001 and were indistinguishable on REP-PCR typing. C. difficile was not cultured from the air or surfaces of either hospital bay during the two days in March 2007. CONCLUSION: This pilot study produced clear evidence of sporadic aerial dissemination of spores of a clone of C. difficile, a finding

BACKGROUND: Cystic fibrosis (CF) is an inherited multi-system disorder characterised by chronic airway infection with pathogens such as Pseudomonas aeruginosa. Acquisition of P. aeruginosa by patients with CF is usually from the environment, but recent studies have demonstrated patient to patient transmission of certain epidemic strains, possibly via an airborne route. This study was designed to examine the survival of P. aeruginosa within artificially generated aerosols. RESULTS: Survival was effected by the solution used for aerosol generation. Within the aerosols it was adversely affected by an increase in air temperature. Both epidemic and non-epidemic strains of P. aeruginosa were able to survive within the aerosols, but strains expressing a mucoid phenotype had a survival advantage. CONCLUSION: This would suggest that segregating individuals free of P. aeruginosa from those with chronic P. aeruginosa infection who are more likely to be infected with mucoid strains may help reduce the risk of cross-infection. Environmental factors also appear to influence bacterial survival. Warming and drying the air within clinical areas and avoidance of humidification devices may also be beneficial in reducing the risk of cross-infection.