207 research outputs found
Pure Framed Braids and 3-Manifolds.
This dissertation looks at representations of framed pure braids and compact orientable three manifolds. A representation, \Phi:Z\sp{n}\oplus P\sb{n}\to \Gamma\sb{n}, is constructed from the framed pure braid group on n strands to the mapping class group on a surface of genus n. The representation is used to obtain a presentation of the fundamental group. The representation, like that of (M-P), is compatible with Heegaard and Surgery descriptions. An algorithm is presented for transforming mapping class group elements to a stably equivalent pure framed braid, under the correspondence given by the representation. A geometric description, using the representation, is given for multiplication in a subgroup of a central extension to the mapping class group coming from (A). A question of providing a group representation development for Witten\u27s three manifold invariant is explored. The result is negative, except for a restricted case of pure framed braids
Therapeutic trajectory following intra-articular hyaluronic acid injection in knee osteoarthritis – meta-analysis
SummaryObjectiveTo evaluate the therapeutic trajectory of intra-articular hyaluronic acid (IAHA) vs placebo for knee osteoarthritis (OA).DesignOur data sources include Medline, EMBASE, CINAHL, BIOSIS, Web of Science, Google Scholar, Cochrane database; hand searched reviews, manuscripts, and, supplements; author contacts for unpublished data. Randomized trials that reported effects of IAHA vs placebo on knee OA were selected based on inclusion criteria. We computed effect sizes for change from baseline at 4, 8, 12, 16, 20 and 24 weeks, using Bayesian random effects model. We performed multivariate analyses adjusting for correlation between time points. Meta-regressions were performed adjusting for potential confounders.ResultsThe 54 eligible trials included 7545 participants. The conduct and quality of these trials varied in number of aspects. The effect size (ES) favored IAHA by week 4 (0.31; 95% CI 0.17, 0.45), reaching peak at week 8 (0.46; 0.28, 0.65), and then trending downwards, with a residual detectable effect at week 24 (0.21; 0.10, 0.31). This therapeutic trajectory was consistent among the subset of high quality trials and on multivariate analysis adjusting for correlation between time points.ConclusionsOur meta-analysis highlights a therapeutic trajectory of IAHA for knee OA pain over 6Â months post-intervention. With this additional perspective, we are able to infer that IAHA is efficacious by 4 weeks, reaches its peak effectiveness at 8 weeks and exerts a residual detectable at 24 weeks. On the other hand, the peak effect size (0.46; 0.28, 0.65), is greater than published effects from other OA analgesics [acetaminophen (ES=0.13; 0.04, 0.22); NSAIDs (ES=0.29; 0.22, 0.35); COX-2 inhibitors (ES=0.44; 0.33, 0.55)]. An effect size above 0.20 is considered to be clinically relevant on an individual patient basis in chronic pain conditions such as knee OA. Thus, its properties could have utility for certain clinical situations, or in combination with other therapies
Double Bark Thickness Estimation Models of Common European Broadleaved Species for Harvester Timber Volume Estimation in Czechia
The share of the annual volume of harvester-produced timber in Czech forest bioeconomy has
increased in the last decades. To estimate under-bark timber volume, harvester systems allow
choosing between two different bark deduction models – diameter band (DBM) and linear
model. However, linear models were not calibrated for the conditions of Czech forestry. Therefore,
the objective of this research was to develop, for local conditions in Czechia, linear functions
for estimating the double bark thickness of two groups of broadleaved species (beech and
oak) and to test their viability based on real harvest data. To create the linear functions, official
Czech cubing tables were used. Data from real harvests were gathered from fifteen harvesters.
A sample containing 4995 logs belonging to the beech group was analyzed using descriptive
statistics and the Paired Wilcoxon tests. The mean double bark thickness for beech group was
15.1 mm (polynomial and linear model). For oak group, it was 15.48 mm (polynomial) or
15.49 mm (linear). The results of real harvests for beech group revealed that the mean double
bark thickness estimated by the polynomial function was 7.08 mm. The linear function estimates
were closer to the value estimated by the polynomial (6.84 mm) than DBM estimates
(6.68 mm). Therefore, we can state that the newly developed linear models can be used in
fully mechanized harvesting instead of manual bark deduction methods in Czechia
Evaluation of stress loading for logging truck drivers by monitoring changes in muscle tension during a work shift
Our research aimed to quantify and evaluate the stress loading of drivers by monitoring the loading of the radial extensor muscle at the wrist joint (musculus extensor carpi radialis) when they drove different types of timber trucks. We monitored changes in the electric potential of skeletal muscles with electromyographic measurements and measurements of changes of heart rate using the Biofeedback 2000 x-pert device. The drivers were observed throughout their work shifts during normal operation of logging trucks and logging trucks with trailers. As a reference, muscle load was measured when driving a passenger car. We evaluated the normality of the measured data and obtained descriptive statistics from the individual measurements. The differences in stress load associated with driving the different types of vehicles increased whilst driving on lower-class roads. Results showed a high stress load for drivers of loaded vehicles when driving on narrow roads. It was more challenging to control a loaded logging truck with a trailer than driving a logging truck, with the difference in muscular loading reaching 22.5%. Driving a logging truck with a trailer produced 46.5% more muscle loading compared to driving a loaded passenger car. For preventive health and safety reasons, it would be reasonable to alternate between drivers when operating various vehicles, thus minimizing the development of possible health issues
Stress-induced O-GlcNAcylation: an adaptive process of injured cells
In the 30 years, since the discovery of nucleocytoplasmic glycosylation, O-GlcNAc has been implicated in regulating cellular processes as diverse as protein folding, localization, degradation, activity, post-translational modifications, and interactions. The cell co-ordinates these molecular events, on thousands of cellular proteins, in concert with environmental and physiological cues to fine-tune epigenetics, transcription, translation, signal transduction, cell cycle, and metabolism. The cellular stress response is no exception: diverse forms of injury result in dynamic changes to the O-GlcNAc subproteome that promote survival. In this review, we discuss the biosynthesis of O-GlcNAc, the mechanisms by which O-GlcNAc promotes cytoprotection, and the clinical significance of these data
Brilliance of a fire: innocence, experience and the theory of childhood
This essay offers an extensive rehabilitation and reappraisal of the concept of childhood innocence as a means of testing the boundaries of some prevailing constructions of childhood. It excavates in detail some of the lost histories of innocence in order to show that these are more diverse and more complex than established and pejorative assessments of them conventionally suggest. Recovering, in particular, the forgotten pedigree of the Romantic account of the innocence of childhood underlines its depth and furnishes an enriched understanding of its critical role in the coming of mass education - both as a catalyst of social change and as an alternative measure of the child-centeredness of the institutions of public education. Now largely and residually confined to the inheritance of nursery education, the concept of childhood innocence, and the wider Romantic project of which it is an element, can help question the assumptions underpinning modern, competence-centred philosophies of childhood
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Safety and efficacy of endoscopic submucosal dissection for rectal neoplasia: a multicenter North American experience.
Background and aims  Rectal lesions traditionally represent the first lesions approached during endoscopic submucosal dissection (ESD) training in the West. We evaluated the safety and efficacy of rectal ESD in North America. Methods  This is a multicenter retrospective analysis of rectal ESD between January 2010 and September 2018 in 15 centers. End points included: rates of en bloc resection, R0 resection, adverse events, comparison of pre- and post-ESD histology, and factors associated with failed resection. Results  In total, 171 patients (median age 63 years; 56 % men) underwent rectal ESD (median size 43 mm). En bloc resection was achieved in 141 cases (82.5 %; 95 %CI 76.8-88.2), including 24 of 27 (88.9 %) with prior failed endoscopic mucosal resection (EMR). R0 resection rate was 74.9 % (95 %CI 68.4-81.4). Post-ESD bleeding and perforation occurred in 4 (2.3 %) and 7 (4.1 %), respectively. Covert submucosal invasive cancer (SMIC) was identified in 8.6 % of post-ESD specimens. There was one case (1/120; 0.8 %) of recurrence at a median follow-up of 31 weeks; IQR: 19-76 weeks). Older age and higher body mass index (BMI) were predictors of failed R0 resection, whereas submucosal fibrosis was associated with a higher likelihood of both failed en bloc and R0 resection. Conclusion  Rectal ESD in North America is safe and is associated with high en bloc and R0 resection rates. The presence of submucosal fibrosis was the main predictor of failed en bloc and R0 resection. ESD can be considered for select rectal lesions, and serves not only to establish a definitive tissue diagnosis but also to provide curative resection for lesions with covert advanced disease
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