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At least 217 records · Page 12Linked to original sources
PubMed2006

Relationship between repetitive work and the prevalence of carpal tunnel syndrome in part-time and full-time female supermarket cashiers: a quasi-experimental study.

OBJECTIVES: To investigate the prevalence of Carpal Tunnel Syndrome (CTS) in full-time and part-time supermarket cashiers exposed to a different weekly duration of biomechanical load. METHODS: All the 269 cashiers and 127 office workers were asked to participate. The protocol included ergonomic risk assessment, collection of personal and clinical data and bilateral electrodiagnostic study of the median nerve. CTS symptoms were defined as past and/or current nocturnal and/or diurnal numbness, tingling, burning or pain involving at least one of the first three fingers. Results were evaluated according to two case definitions based on current symptoms and on the combination of current symptoms and slowing of sensory conduction velocity from wrist to palm, respectively. Difference in proportions of CTS symptoms and cases was evaluated by the Pearson's chi-square (chi(2)) test, univariate and multivariate logistic regression analyses were performed to determine the impact of weekly exposure. RESULTS: The final female study population included 71 full-time cashiers, 155 part-time cashiers and 98 office workers. Ergonomic risk level was rated 5 for hand activity level and 4 for peak of force according to ACGIH. The intersection of the two values fell on the threshold limit value line, confirming the possible exposure to biomechanical risk factors for CTS. The prevalence of current CTS symptoms was higher among full-time (31.0%) than in part-time cashiers (19.3%) or controls (16.3%) (p = 0.055). A similar pattern was found for CTS past symptoms and cases. Univariate analysis showed that full-time cashiers had a 2.3 fold increased risk for CTS specific current symptoms than control subjects. A similar trend also emerged for CTS cases but was not significant (Odds ratios 1.23). Multivariate logistic regression analysis confirmed the increased risk for CTS current symptoms in full-time cashiers. CONCLUSIONS: Intensive manual work associated with inadequate recovery time might have generated an impairment of the median nerve at the wrist level proportionally increasing with duration of hand use. Our study can provide useful information both for ergonomic risk assessment and work organization.

Adult↗
PubMed2003

Real-time independent component analysis of fMRI time-series.

Real-time functional magnetic resonance imaging (fMRI) enables one to monitor a subject's brain activity during an ongoing session. The availability of online information about brain activity is essential for developing and refining interactive fMRI paradigms in research and clinical trials and for neurofeedback applications. Data analysis for real-time fMRI has traditionally been based on hypothesis-driven processing methods. Off-line data analysis, conversely, may be usefully complemented by data-driven approaches, such as independent component analysis (ICA), which can identify brain activity without a priori temporal assumptions on brain activity. However, ICA is commonly considered a time-consuming procedure and thus unsuitable to process the high flux of fMRI data while they are acquired. Here, by specific choices regarding the implementation, we exported the ICA framework and implemented it into real-time fMRI data analysis. We show that, reducing the ICA input to a few points within a time-series in a sliding-window approach, computational times become compatible with real-time settings. Our technique produced accurate dynamic readouts of brain activity as well as a precise spatiotemporal history of quasistationary patterns in the form of cumulative activation maps and time courses. Results from real and simulated motor activation data show comparable performances for the proposed ICA implementation and standard linear regression analysis applied either in a sliding-window or in a cumulative mode. Furthermore, we demonstrate the possibility of monitoring transient or unexpected neural activities and suggest that real-time ICA may provide the fMRI researcher with a better understanding and control of subjects' behaviors and performances.

Algorithms↗
PubMed1979

Sequential predictability effects on initiation time and movement time for adults and children.

First-grade children and adults performed a two-choice initiation-time/ movement-time task in which signals were (a) more likely to repeat than alternate, (b) more likely to alternate than repeat or (c) equally likely to alternate or repeat. Sequential predictability influenced initiation time but not movement time for adults and for children. These results do not support the suggestion (Wickens, 1974) that sequential predictability affects initiation time and movement time for children but only initiation time for adults. Adults and first graders did differ in their response to repeated events. Adults averaged faster initiation time for alternated than repeated responses and children averaged faster initiation time for repeated than alternated responses.

Journal Article↗
PubMed2001

Influence of plasticization time, curing conditions, storage time, and core properties on the drug release from Aquacoat-coated pellets.

Theophylline or chlorpheniramine maleate pellets were coated with an aqueous ethylcellulose dispersion, Aquacoat. The influence of the plasticization time, curing conditions, storage time, and core properties on the drug release were investigated. The plasticization time (time between plasticizer addition to the polymer dispersion and the spraying process) did not affect the drug release, when the water-soluble plasticizer triethyl citrate, was used because of its rapid uptake by the colloidal polymer particles. In contrast, with the water-insoluble plasticizer acetyltributyl citrate (ATBC), plasticization time (1/2 h vs 24 h) influenced the drug release, the longer plasticization time resulted in a slower drug release because of a more complete plasticizer uptake prior to the coating step. However a thermal aftertreatment of the coated pellets at eleylated temperatures (curing step) reduced/eliminated the effect of the plasticization time with ATBC. In general, curing reduced the drug release and resulted in stable drug release profiles. The time period between the coating and the curing step was not critical when the pellets were cured for a longer time. The structure of the pellet core (high dose matrix vs low dose layered pellet) strongly affected the drug release. A slow, zero-order drug release was obtained with high dose theophylline pellets, while a more rapid, first-order release pattern was obtained with low dose theophylline-layered nonpareil pellets.

Cellulose↗
PubMed1997

Renal vascular transit time and tubular transit time dispersion for 99Tcm-MAG3.

Renal transit time usually refers to tubular transit time, as introduced by Taplin, but other measures of renal transit have been proposed. Here we examine the vascular transit time (VTT, following Rutland) and the standard deviation of tubular transit time (SDTT, following Britton) in a group of 30 patients having baseline and ACE-inhibitor 99Tcm-MAG3 renography prior to arteriography. A same-day, low-dose/high-dose protocol was used for renography; only the post-captopril dose was high enough to measure VTT. Pre-captopril, the Spearman rank correlation coefficient for SDTT was rho = 0.52 (n = 53 kidneys; P < 0.0002); post-captopril, rho = 0.54 (n = 49 kidneys; P < 0.0002). For VTT, the post-captopril value was rho = 0.24 (n = 30 kidneys; N.S.). For comparison, the same statistics were calculated for Taplin's original measure of transit time: the time from injection to maximum count rate (peak time). Pre-captopril, for peak time, rho was 0.47 (n = 53 kidneys; P < 0.001); post-captopril, rho was 0.39 (n = 50 kidneys, P < 0.01). These findings confirm the diagnostic value of SDTT but not of VTT. SDTT correlated better than peak time with the arteriographic findings.

Adult↗
PubMed2006

Injured patients have lower mortality when treated by "full-time" trauma surgeons vs. surgeons who cover trauma "part-time".

BACKGROUND: Studies examining the effect of trauma surgeon volume on patient outcomes have had disparate results. We hypothesize that "full-time" trauma surgeons would have lower patient mortality rates than surgeons covering trauma "part-time." METHODS: Retrospective review of 14,171 patients during a span of 6.5 years (January 1998 to June 2004) from the trauma registry at an urban, university-based Level I trauma center. "Full-time" surgeons practiced primarily trauma, emergency surgery, and critical care. "Part-time" surgeons took trauma call, but mainly practiced another type of surgery (e.g., pancreatic, hepatobiliary, vascular, transplant). Chi square and multiple logistic regression compared mortality between groups. RESULTS: There were no differences in patient demographics or admission injury patterns between the two groups. On bivariate analysis, the subgroup of patients with severe head injury had lower mortality when treated by "full-time" surgeons. With ED deaths excluded, more severely injured patients (Injury Severity Score [ISS] >15) had a survival benefit in the "full-time" group. Multiple logistic regression showed a 50% increase in mortality for patients treated by "part-time" trauma surgeons when adjusting for age, sex, ISS >15, severe head injury, hypotension, nighttime admission, day of the week, and penetrating mechanism (odds ratio of death 1.45, 95% CI 1.04-2.02). Similar results are seen in only patients surviving to emergency room discharge (odds ratio of death 1.50, 95% CI 1.01-2.22). Z and W scores showed higher than expected survival for all patients with the "full-time" cohort showing a larger benefit. CONCLUSIONS: Even within an established trauma program treating many injured patients, mortality is significantly lower in patients initially treated by "full-time" trauma surgeons.

Adult↗
PubMed2005

Real-time dynamics in spin-1/2 chains with adaptive time-dependent density matrix renormalization group.

We investigate the influence of different interaction strengths and dimerizations on the magnetization transport in antiferromagnetic spin 1/2 XXZ chains. We focus on the real-time evolution of the inhomogeneous initial state |upward arrow... upward arrow downward arrow... downward arrow > in using the adaptive time-dependent density-matrix renormalization group (adaptive t-DMRG). Time scales accessible to us are of the order of 100 units of time measured in Planck's/J for almost negligible error in the observables. We find ballistic magnetization transport for small S(z) S(z) interaction and arbitrary dimerization, but almost no transport for stronger S(z) S(z) interaction, with a sharp crossover at J(z) =1 . Additionally, we perform a detailed analysis of the error made by the adaptive time-dependent DMRG using the fact that the evolution in the XX model is known exactly. We find that the error at small times is dominated by the error made by the Trotter decomposition, whereas for longer times the DMRG truncation error becomes the most important, with a very sharp crossover at some "runaway" time. Overall, errors are extremely small before the "runaway" time.

Journal Article↗