2,196 research outputs found

    Protocol: Using single-case experimental design to evaluate whole-body dynamic seating on activity, participation, and quality of life in dystonic cerebral palsy

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    INTRODUCTION: People with hyperkinetic movement disorders, including dystonia, experience often painful, involuntary movements affecting functioning. Seating comfort is a key unmet need identified by families. This paper reports a protocol to assess the feasibility and preliminary evidence for the efficacy of dynamic seating to improve functional outcomes for young children with dystonic cerebral palsy (DCP). DESIGN: A series of single-case experimental design N-of-1 trials, with replications across participants, with a random baseline interval, and one treatment period (n = 6). METHODS: Inclusion criteria: DCP; 21.5 cm < popliteal fossa to posterior sacrum < 35 cm; Gross Motor Function Classification System level IV–V; mini-Manual Ability Classification System level IV–V; difficulties with seating. INTERVENTION: Trial of the seat (8 weeks), with multiple baseline before, during and after intervention and 2 month follow up. The baseline duration will be randomised per child (2–7 weeks). PRIMARY OUTCOMES: Performance Quality Rating Scale; Canadian Occupational Performance Measure; seating tolerance. The statistician will create the randomization, with allocation concealment by registration of participants prior to sending the allocation arm to the principal investigator. Primary outcomes will be assessed from video by an assessor blind to allocation. ANALYSIS: Participant outcome data will be plotted over time, with parametric and non-parametric analysis including estimated size effect for N-of-1 trials

    The Symmetry of Neural Stem Cell and Progenitor Divisions in the Vertebrate Brain

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    Robust brain development requires the tight coordination between tissue growth, neuronal differentiation and stem cell maintenance. To achieve this, neural stem cells need to balance symmetric proliferative and terminal divisions with asymmetric divisions. In recent years, the unequal distribution of certain cellular components in mitosis has emerged as a key mechanism to regulate the symmetry of division, and the determination of equal and unequal sister cell fates. Examples of such components include polarity proteins, signaling components, and cellular structures such as endosomes and centrosomes. In several types of neural stem cells, these factors show specific patterns of inheritance that correlate to specific cell fates, albeit the underlying mechanism and the potential causal relationship is not always understood. Here, we review these examples of cellular neural stem and progenitor cell asymmetries and will discuss how they fit into our current understanding of neural stem cell function in neurogenesis in developing and adult brains. We will focus mainly on the vertebrate brain, though we will incorporate relevant examples from invertebrate organisms as well. In particular, we will highlight recent advances in our understanding of the complexities related cellular asymmetries in determining division mode outcomes, and how these mechanisms are spatiotemporally regulated to match the different needs for proliferation and differentiation as the brain forms

    Endorsement and Constructive Criticism of an Innovative Online Reflexive Self-Talk Intervention

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    This study prospectively followed the experiences of skilled athletes who were involved in an innovative reflexive self-talk online intervention targeting goal-directed self-talk. Four experienced female athletes between the ages of 20 and 40 years were invited to an initial interview, a 4-week intervention, and two post-intervention interviews. Two applied sport psychologists used an online Socratic questioning approach to encourage their athletes to describe challenging scenarios, think about their use of self-talk and its effectiveness, and explore alternative self-statements that could be used in future situations. Data were multi-sourced stemming from the psychologists, athletes, and third parties (e.g., coach). Three athletes completed the intervention, whereas one athlete withdrew prematurely, mainly because the Socratic questioning approach and the online mode of delivery did not meet her preferences. From the three athlete who had completed the intervention, there was endorsement and constructive criticism of the intervention and its online delivery mode. The intervention, largely due to the accompanying raised awareness of self-talk use and refined content, seemingly benefited a range of variables including emotions, motivation, and confidence, both inside and outside of the athletes' sports life domain. Accordingly, this new type of online intervention warrants further consideration in the literature

    High-pressure speed of sound in pure CO2 and in CO2 with SO2 as an impurity using methanol as a doping agent

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    Reliable speed of sound, c, values in CO2- rich mixtures and pure CO2 are required for carbon capture and storage (CCS) technology but are difficult to determine, particularly at relatively high frequencies. We tested the suitability of methanol as doping agent to obtain accurate c values in CCS systems at 5 MHz. We measured c in seven CO2-rich, CO2 + methanol mixtures between 263.15 and 323.15 K and up to 196.30 MPa, and we extrapolated the values to obtain c in pure CO2. Additionally, we measured c from 263.15 to 373.19 K and up to 190.10 MPa in two CO2-rich, CO2 + SO2 mixtures with the same SO2 composition, which is of interest for CCS, with one mixture doped with methanol. We compared our results for pure CO2 with the literature and the Span and Wagner equation of state (EoS). We validated the PC-SAFT EoS and the modeling with the REFPROP 9 software for the mixtures by comparing the predicted values with our experimental data under the studied conditions. We conclude that methanol is a suitable doping agent to measure c in pure CO2 and CO2-rich mixtures. For the CO2 + SO2 mixtures, the effect of methanol on the experimental values is small and negligible for modeling

    Unexplained hydrogen isotope offsets complicate the identification and quantification of tree water sources in a riparian forest

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    We investigated plant water sources of an emblematic refugial population of Fagus sylvatica (L.) in the Ciron river gorges in south-western France using stable water isotopes. It is generally assumed that no isotopic fractionation occurs during root water uptake, so that the isotopic composition of xylem water effectively reflects that of source water. However, this assumption has been called into question by recent studies that found that, at least at some dates during the growing season, plant water did not reflect any mixture of the potential water sources. In this context, highly resolved datasets covering a range of environmental conditions could shed light on possible plant–soil fractionation processes responsible for this phenomenon. In this study, the hydrogen (δ2H) and oxygen (δ18O) isotope compositions of all potential tree water sources and xylem water were measured fortnightly over an entire growing season. Using a Bayesian isotope mixing model (MixSIAR), we then quantified the relative contribution of water sources for F. sylvatica and Quercus robur (L.) trees. Based on δ18O data alone, both species used a mix of top and deep soil water over the season, with Q. robur using deeper soil water than F. sylvatica. The contribution of stream water appeared to be marginal despite the proximity of the trees to the stream, as already reported for other riparian forests. Xylem water δ18O could always be interpreted as a mixture of deep and shallow soil waters, but the δ2H of xylem water was often more depleted than the considered water sources. We argue that an isotopic fractionation in the unsaturated zone and/or within the plant tissues could underlie this unexpected relatively depleted δ2H of xylem water, as already observed in halophytic and xerophytic species. By means of a sensitivity analysis, we found that the estimation of plant water sources using mixing models was strongly affected by this δ2H depletion. A better understanding of what causes this isotopic separation between xylem and source water is urgently needed.</p

    Influence of SO2 on CO2 Transport by Pipeline for Carbon Capture and Storage Technology: Evaluation of CO2/SO2 Cocapture

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    CO2 capture and storage (CCS) is an important technology for avoiding atmospheric CO2 emissions, which are principally originated from fossil fuels combustion. Anthropogenic CO2 contains impurities that can strongly modify the properties of the stream. Several authors have shown that some of these impurities, such as SO2 present in emissions from sulfur-containing fuels, could be favorable for some steps of the process, and the possibility of cocapture has been proposed. To assess this possibility with regard to the transport stage of CCS, we determined the influence of SO2 on selected parameters of transport by pipeline (minimal operational pressure, pressure and density drops, distance between boosters, booster power, and inner diameter of the pipeline, and the Joule-Thomson coefficient). For this purpose, we obtained new and accurate experimental data for the density and vapor–liquid equilibrium of five CO2 + SO2 mixtures under conditions of interest for CCS and speed of sound data for four of them. We compared our results to those found in the literature and to the values calculated using two equations of state for their validation: perturbed-chain statistical associating fluid theory (PC-SAFT) and an extended version of equation of state for combustion gases (EOS-CG) that includes a binary model for the CO2 + SO2 mixture. Allowing for the fact that chemical effects due to the presence of SO2, such as pipeline corrosion, have not been considered, we conclude that CO2/SO2 cocapture might favor and decrease the costs of the transport step of this technology, helping to avoid emissions of a highly toxic gas to the atmosphere without high desulfuration expenses

    Effect of nucleon exchange on projectile multifragmentation in the reactions of 28Si + 112Sn and 124Sn at 30 and 50 MeV/nucleon

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    Multifragmentation of quasiprojectiles was studied in reactions of 28Si beam with 112Sn and 124Sn targets at projectile energies 30 and 50 MeV/nucleon. The quasiprojectile observables were reconstructed using isotopically identified charged particles with Z_f <= 5 detected at forward angles. The nucleon exchange between projectile and target was investigated using isospin and excitation energy of reconstructed quasiprojectile. For events with total reconstructed charge equal to the charge of the beam (Z_tot = 14) the influence of beam energy and target isospin on neutron transfer was studied in detail. Simulations employing subsequently model of deep inelastic transfer, statistical model of multifragmentation and software replica of FAUST detector array were carried out. A concept of deep inelastic transfer provides good description of production of highly excited quasiprojectiles. The isospin and excitation energy of quasiprojectile were described with good overall agreement. The fragment multiplicity, charge and isospin were reproduced satisfactorily. The range of contributing impact parameters was determined using backtracing procedure.Comment: 11 pages, 8 Postscript figures, LaTeX, to appear in Phys. Rev. C ( Dec 2000

    Underlying molecular mechanism in the modulation of the ram sperm acrosome reaction by progesterone and 17Ăź-estradiol

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    Steroid hormones progesterone (P4) and 17ß-estradiol (E2) not only have important functions in regulation of reproductive processes in mammals but also have direct effects on spermatozoa. There can be induction of the acrosome reaction in ram spermatozoa by P4 and E2 and, in the present study, there was further investigation of mechanisms underlying this effect. In a medium containing agents that increase cAMP, the presence of both P4 and E2 led to changes in the localization of proteins phosphorylated in tyrosine residues evaluated by indirect immunofluorescence. The inclusion of P4 at 1 µM in the media induced an increase in Ca2+i and mobilization in the area of the acrosome (Fluo-4 and Rhod-5 staining, respectively), an increase in ROS (H2DCFDA staining) and a substantial disruption of the acrosome (evaluated using RCA), while E2 did not have these effects. There were no effects on cAMP concentrations or PKA activity with inclusion of these hormones in the media. The inclusion of P4 at 100 pM in the media led to changes in values for sperm kinematic variables which could indicate there was an inhibition of the hyperactivation caused by agents that induce an increase in cAMP concentrations. In conclusion, results from the present study indicate that P4 and E2 promote mechanisms regulating the acrosome reaction in ram spermatozoa, however, these effects on mechanisms are different for the two hormones, and for E2, require further clarification

    Physical Activity Characteristics across GOLD Quadrants Depend on the Questionnaire Used

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    BACKGROUND:The GOLD multidimensional classification of COPD severity combines the exacerbation risk with the symptom experience, for which 3 different questionnaires are permitted. This study investigated differences in physical activity (PA) in the different GOLD quadrants and patient's distribution in relation to the questionnaire used. METHODS:136 COPD patients (58±21% FEV1 predicted, 34F/102M) completed COPD assessment test (CAT), clinical COPD questionnaire (CCQ) and modified Medical Research Council (mMRC) questionnaire. Exacerbation history, spirometry and 6MWD were collected. PA was objectively measured for 2 periods of 1 week, 6 months apart, in 5 European centres; to minimise seasonal and clinical variation the average of these two periods was used for analysis. RESULTS:GOLD quadrants C+D had reduced PA compared with A+B (3824 [2976] vs. 5508 [4671] steps.d-1, p<0.0001). The choice of questionnaire yielded different patient distributions (agreement mMRC-CAT κ = 0.57; CCQ-mMRC κ = 0.71; CCQ-CAT κ = 0.72) with different clinical characteristics. PA was notably lower in patients with an mMRC score ≥2 (3430 [2537] vs. 5443 [3776] steps.d-1, p <0.001) in both the low and high risk quadrants. CONCLUSIONS:Using different questionnaires changes the patient distribution and results in different clinical characteristics. Therefore, standardization of the questionnaire used for classification is critical to allow comparison of different studies using this as an entry criterion. CLINICAL TRIAL REGISTRATION:ClinicalTrials.gov NCT01388218
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