159 research outputs found
The effect of signal acquisition and processing choices on ApEn values: Towards a “gold standard” for distinguishing effort levels from isometric force records
Approximate Entropy (ApEn) is frequently used to identify changes in the complexity of isometric force records with ageing and disease. Different signal acquisition and processing parameters have been used, making comparison or confirmation of results difficult. This study determined the effect of sampling and parameter choices by examining changes in ApEn values across a range of submaximal isometric contractions of the First Dorsal Interosseus. Reducing the sample rate by decimation changed both the value and pattern of ApEn values dramatically. The pattern of ApEn values across the range of effort levels was not sensitive to the filter cut-off frequency, or the criterion used to extract the section of data for analysis. The complexity increased with increasing effort levels using a fixed ‘r’ value (which accounts for measurement noise) but decreased with increasing effort level when ‘r’ was set to 0.1 of the standard deviation of force. It is recommended isometric force records are sampled at frequencies >200 Hz, template length (‘m’) is set to 2, and 'r' set to measurement system noise or 0.1 SD depending on physiological process to be distinguished. It is demonstrated that changes in ApEn across effort levels are related to changes in force gradation strategy
Identification of Immunoreactive Material in Mammoth Fossils
The fossil record represents a history of life on this planet. Attempts to obtain molecular information from this record by analysis of nucleic acids found within fossils of extreme age have been unsuccessful or called into question. However, previous studies have demonstrated the long-term persistence of peptides within fossils and have used antibodies to extant proteins to demonstrate antigenic material. In this study we address two questions: Do immunogenic/antigenic materials persist in fossils? and; Can fossil material be used to raise antibodies that will cross-react with extant proteins? We have used material extracted from a well-preserved 100,000-300,000-year-old mammoth skull to produce antisera. The specificity of the antisera was tested by ELISA, western blotting, and immunohistochemistry. It was demonstrated that antisera reacted specifically with the fossils and no the surrounding sediments. Reactivity of antisera with modern proteins and tissues was also demonstrated, as was the ability to detect evolutionary relationships via antibody-antigen interactions. Mass spectrometry demonstrated the response of amino acids and specific peptides within the fossil. Peptides were purified by anion-exchange chromatography and sequenced by tandem mass spectrometry. The collagen-derived peptides may have been the source of at least some of the immunologic reactivity, but the antisera identified molecules that were not observed by mass spectrometry, indicating that immunologic methods may have greater sensitivity. Although the presence of peptides and amino acids was demonstrated, the exact nature of the antigenic material was not fully clarified. This report demonstrated that antibodies may be used to obtain information from the fossil record
Metal Contents in Fish from the Bay of Bengal and Potential Consumer Exposure—The EAF-Nansen Programme
Fish represent an important part of the Sri Lankan and Bangladeshi diet. However, fish is also a source of contaminants that may constitute a health risk to consumers. The aim of this study was to analyse the contents of arsenic, cadmium, mercury, and lead in 24 commonly consumed marine fish species from the Bay of Bengal and to assess the potential health risk associated with their consumption. Mercury and lead contents did not exceed the maximum limits for any of the sampled species, and consumer exposure from estimated daily consumption was assessed to be minimal for adults and children. Numerous samples exceeded the maximum limit for cadmium (58%), particularly those of small size (≤25 cm). However, consumer exposure was insignificant, and health assessment showed no risk connected to consumption. These data represent an important contribution to future risk/benefit assessments related to the consumption of fish.publishedVersio
Mesoscopic models for DNA stretching under force: new results and comparison to experiments
Single molecule experiments on B-DNA stretching have revealed one or two
structural transitions, when increasing the external force. They are
characterized by a sudden increase of DNA contour length and a decrease of the
bending rigidity. It has been proposed that the first transition, at forces of
60--80 pN, is a transition from B to S-DNA, viewed as a stretched duplex DNA,
while the second one, at stronger forces, is a strand peeling resulting in
single stranded DNAs (ssDNA), similar to thermal denaturation. But due to
experimental conditions these two transitions can overlap, for instance for
poly(dA-dT). We derive analytical formula using a coupled discrete worm like
chain-Ising model. Our model takes into account bending rigidity, discreteness
of the chain, linear and non-linear (for ssDNA) bond stretching. In the limit
of zero force, this model simplifies into a coupled model already developed by
us for studying thermal DNA melting, establishing a connexion with previous
fitting parameter values for denaturation profiles. We find that: (i) ssDNA is
fitted, using an analytical formula, over a nanoNewton range with only three
free parameters, the contour length, the bending modulus and the monomer size;
(ii) a surprisingly good fit on this force range is possible only by choosing a
monomer size of 0.2 nm, almost 4 times smaller than the ssDNA nucleobase
length; (iii) mesoscopic models are not able to fit B to ssDNA (or S to ss)
transitions; (iv) an analytical formula for fitting B to S transitions is
derived in the strong force approximation and for long DNAs, which is in
excellent agreement with exact transfer matrix calculations; (v) this formula
fits perfectly well poly(dG-dC) and -DNA force-extension curves with
consistent parameter values; (vi) a coherent picture, where S to ssDNA
transitions are much more sensitive to base-pair sequence than the B to S one,
emerges.Comment: 14 pages, 9 figure
Three (Potential) Pillars of Transnational Economic Justice: The Bretton Woods Institutions as Guarantors of Global Equal Treatment and Market Completion
This essay aims to bring two important lines of inquiry and criticism together. It first lays out an institutionally enriched account of what a just world economic order will look like. That account prescribes, via the requisites to that mechanism which most directly instantiate the account, three realms of equal treatment and market completion - the global products, services, and labor markets; the global investment/financial markets; and the global preparticipation opportunity allocation. The essay then suggests how, with minimal if any departure from familiar canons of traditional international legal mandate interpretation, each of the Bretton Woods institutions - particularly the GATT/WTO and the IMF - can be viewed at least in part as charged with the task of fostering equal treatment and ultimate market completion within one of those three realms. The piece then argues that one of the institutions in particular - the World Bank - has, for reasons of at best negligent and at worst willful injustice on the part of influential state actors in the world community, fallen farthest short in pursuit of what should be viewed as its proper mandate. The article accordingly concludes that a fuller empowerment of the Bank to effect its ideal mission will press the Bretton Woods system more nearly into ethical balance, and with it the world into justice; and that full empowerment of the GATT/WTO and IMF should be partly conditioned upon the fuller empowerment of the Bank
Expectations, perceptions, and physiotherapy predict prolonged sick leave in subacute low back pain
<p>Abstract</p> <p>Background</p> <p>Brief intervention programs for subacute low back pain (LBP) result in significant reduction of sick leave compared to treatment as usual. Although effective, a substantial proportion of the patients do not return to work. This study investigates predictors of return to work in LBP patients participating in a randomized controlled trial comparing a brief intervention program (BI) with BI and physical exercise.</p> <p>Methods</p> <p>Predictors for not returning to work was examined in 246 patients sick listed 8-12 weeks for low back pain. The patients had participated in a randomized controlled trial, with BI (n = 122) and BI + physical exercise (n = 124). There were no significant differences between the two intervention groups on return to work. The groups were therefore merged in the analyses of predictors. Multiple logistic regression analysis was used to identify predictors for non return to work at 3, 12, and 24 months of follow-up.</p> <p>Results</p> <p>At 3 months of follow-up, the strongest predictors for not returning to work were pain intensity while resting (OR = 5.6; CI = 1.7-19), the perception of constant back strain when working (OR = 4.1; CI = 1.5-12), negative expectations for return to work (OR = 4.2; CI = 1.7-10), and having been to a physiotherapist prior to participation in the trial (OR = 3.3; CI = 1.3-8.3). At 12 months, perceived reduced ability to walk far due to the complaints (OR = 2.6; CI = 1.3-5.4), pain during activities (OR = 2.4; CI = 1.1-5.1), and having been to a physiotherapist prior to participation in the trial (OR = 2.1; CI = 1.1-4.3) were the strongest predictors for non return to work. At 24 months age below 41 years (OR = 2.9; CI = 1.4-6.0) was the only significant predictor for non return to work.</p> <p>Conclusion</p> <p>It appears that return to work is highly dependant on individual and cognitive factors. Patients not returning to work after the interventions were characterized by negative expectations, perceptions about pain and disability, and previous physiotherapy treatment. This is the first study reporting that previous treatment by physiotherapists is a risk factor for long-term sick leave. This has not been reported before and is an interesting finding that deserves more scrutiny.</p
Data-analysis strategies for image-based cell profiling
Image-based cell profiling is a high-throughput strategy for the quantification of phenotypic differences among a variety of cell populations. It paves the way to studying biological systems on a large scale by using chemical and genetic perturbations. The general workflow for this technology involves image acquisition with high-throughput microscopy systems and subsequent image processing and analysis. Here, we introduce the steps required to create high-quality image-based (i.e., morphological) profiles from a collection of microscopy images. We recommend techniques that have proven useful in each stage of the data analysis process, on the basis of the experience of 20 laboratories worldwide that are refining their image-based cell-profiling methodologies in pursuit of biological discovery. The recommended techniques cover alternatives that may suit various biological goals, experimental designs, and laboratories' preferences.Peer reviewe
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