396 research outputs found

    Effects of neutral gas release on current collection during the CHARGE-2 rocket experiment

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    Observations of current collection enhancements due to cold nitrogen gas control jet emissions from a highly charged rocket payload in the ionosphere are reported. These observations were made during the second cooperative high altitude rocket gun experiment (CHARGE-2) which was an electrically tethered mother/daughter payload system. The current collection enhancement was observed at the daughter payload located 100 to 400 m away from the mother which was firing an energetic electron beam. The authors interpret these results in terms of an electrical discharge forming in close proximity to the daughter during the short periods of gas emission. The results indicate that it is possible to enhance the electron current collection capability of positively charged vehicles by means of deliberate neutral gas releases into an otherwise undisturbed space plasma. These results can also be compared with recent laboratory observations of hollow cathode plasma contactors operating in the ignited mode. Experimental observations of current collection enhancements due to cold nitrogen gas control jet emissions from a highly charged, isolated daughter payload in the nighttime ionosphere were made. These observations were derived from the second cooperative high altitude rocket gun experiment (CHARGE-2) which was an electrically tethered mother-daughter payload system. The rocket flew from White Sands Missile Range (WSMR) in December, 1985. The rocket achieved an altitude of 261 km and carried a 1 keV electron beam emitting up to 48 mA of current (Myers, et al., 1989a). The mother payload, carried the electron beam source, while the daughter acted as a remote current collection and observation platform and reached a distance of 426 m away from the main payload. Gas emissions at the daughter were due to periodic thruster jet firings to maintain separation velocity between the two payloads

    Contextualized Treatment in Traumatic Brain Injury Inpatient Rehabilitation: Effects on Outcomes During the First Year after Discharge

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    Objective To evaluate the effect of providing a greater percentage of therapy as contextualized treatment on acute traumatic brain injury (TBI) rehabilitation outcomes. Design Propensity score methods are applied to the TBI-Practice-Based Evidence (TBI-PBE) database, a database consisting of multi-site, prospective, longitudinal observational data. Setting Acute inpatient rehabilitation. Participants Patients enrolled in the TBI-PBE study (n=1843), aged 14 years or older, who sustained a severe, moderate, or complicated mild TBI, receiving their first IRF admission in the US, and consented to follow-up 3 and 9 months post discharge from inpatient rehabilitation. Interventions Not applicable. Main Outcome Measures Participation Assessment with Recombined Tools-Objective- -17, FIMTM Motor and Cognitive scores, Satisfaction with Life Scale and Patient Health Questionnaire-9. Results Increasing the percentage of contextualized treatment during inpatient TBI rehabilitation leads to better outcomes, specifically in regard to community participation. Conclusions Increasing the proportion of treatment provided in the context of real-life activities appears to have a beneficial impact on outcome. Although the effect sizes are small, the results are consistent with other studies supporting functional-based interventions effecting better outcomes. Furthermore, any positive findings, regardless of size or strength, are endorsed as important by consumers (survivors of TBI). While the findings do not imply that decontextualized treatment should not be used, when the therapy goal can be addressed with either approach, the findings suggest that better outcomes may result if the contextualized approach is used

    Exhaled breath hydrogen cyanide as a marker of early Pseudomonas aeruginosa infection in children with cystic fibrosis

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    Hydrogen cyanide is readily detected in the headspace above Pseudomonas aeruginosa cultures and in the breath of cystic fibrosis (CF) patients with chronic (P. aeruginosa) infection. We investigated if exhaled breath HCN is an early marker of P. aeruginosa infection. 233 children with CF who were free from P. aeruginosa infection were followed for 2 years. Their median (interquartile range) age was 8.0 (5.0–12.2) years. At each study visit, an exhaled breath sample was collected for hydrogen cyanide analysis. In total, 2055 breath samples were analysed. At the end of the study, the hydrogen cyanide concentrations were compared to the results of routine microbiology surveillance. P. aeruginosa was isolated from 71 children during the study with an incidence (95% CI) of 0.19 (0.15–0.23) cases per patient-year. Using a random-effects logistic model, the estimated odds ratio (95% CI) was 3.1 (2.6–3.6), which showed that for a 1- ppbv increase in exhaled breath hydrogen cyanide, we expected a 212% increase in the odds of P. aeruginosa infection. The sensitivity and specificity were estimated at 33% and 99%, respectively. Exhaled breath hydrogen cyanide is a specific biomarker of new P. aeruginosa infection in children with CF. Its low sensitivity means that at present, hydrogen cyanide cannot be used as a screening test for this infection

    The Sixth Transmembrane Segment Is a Major Gating Component of the TMEM16A Calcium-Activated Chloride Channel.

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    Calcium-activated chloride channels (CaCCs) formed by TMEM16A or TMEM16B are broadly expressed in the nervous system, smooth muscles, exocrine glands, and other tissues. With two calcium-binding sites and a pore within each monomer, the dimeric CaCC exhibits voltage-dependent calcium sensitivity. Channel activity also depends on the identity of permeant anions. To understand how CaCC regulates neuronal signaling and how CaCC is, in turn, modulated by neuronal activity, we examined the molecular basis of CaCC gating. Here, we report that voltage modulation of TMEM16A-CaCC involves voltage-dependent occupancy of calcium- and anion-binding site(s) within the membrane electric field as well as a voltage-dependent conformational change intrinsic to the channel protein. These gating modalities all critically depend on the sixth transmembrane segment

    Increased dispersion of oil from a deep water seabed release by energetic mesoscale eddies

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    Hydrodynamics play a critical role in determining the trajectory of an oil spill. Currents, stratification and mesoscale processes all contribute to how a spill behaves. Using an industry‑leading oil spill model, we compare forecasts of oil dispersion when forced with two different hydrodynamic models of the North-West European Shelf (7 km and 1.5 km horizontal resolution). This demonstrates how the trajectory of a deep water (>1000 m) release in the central Faroe-Shetland Channel is influenced by explicitly resolving mesoscale processes. The finer resolution hydrodynamic model dramatically enhances the horizontal dispersion of oil and transports pollutant further afield. This is a consequence of higher mesoscale variability. Stratification influences the depth of subsurface plume trapping and subsequently the far-field transport of oil. These results demonstrate that the choice of hydrodynamic model resolution is crucial when designing particle tracking or tracer release experiments

    Advanced Therapy in Traumatic Brain Injury Inpatient Rehabilitation: Effects on Outcomes During the First Year after Discharge

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    Objective To use causal inference methods to determine if receipt of a greater proportion inpatient rehabilitation treatment focused on higher level functions, e.g. executive functions, ambulating over uneven surfaces (Advanced Therapy, AdvTx) results in better rehabilitation outcomes. Design A cohort study using propensity score methods applied to the TBI-Practice-Based Evidence (TBI-PBE) database, a database consisting of multi-site, prospective, longitudinal observational data. Setting Acute inpatient rehabilitation (IRF). Participants Patients enrolled in the TBI-PBE study (n=1843), aged 14 years or older, who sustained a severe, moderate, or complicated mild TBI, receiving their first IRF admission to one of 9 sites in the US, and consented to follow-up 3 and 9 months post discharge from inpatient rehabilitation. Interventions Not applicable. Main Outcome Measures: Participation Assessment with Recombined Tools-Objective-17, FIMTM Motor and Cognitive scores, Satisfaction with Life Scale, and Patient Health Questionnaire-9. Results Controlling for measured potential confounders, increasing the percentage of AdvTx during inpatient TBI rehabilitation was found to be associated with better community participation, functional independence, life satisfaction, and decreased likelihood of depression during the year following discharge from inpatient rehabilitation. Participants who began rehabilitation with greater disability experienced larger gains on some outcomes than those who began rehabilitation with more intact abilities. Conclusions Increasing the proportion of treatment targeting higher level functions appears to have no detrimental and a small, beneficial effect on outcome. Caution should be exercised when inferring causality given that a large number of potential confounders could not be completely controlled with propensity score methods. Further, the extent to which unmeasured confounders influenced the findings is not known and could be of particular concern due to the potential for the patient’s recovery trajectory to influence therapists’ decisions to provide a greater amount AdvTx

    Magnetic-field and current-density distributions in thin-film superconducting rings and disks

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    We show how to calculate the magnetic-field and sheet-current distributions for a thin-film superconducting annular ring (inner radius a, outer radius b, and thickness d<<a) when either the penetration depth obeys lambda < d/2 or, if lambda > d/2, the two-dimensional screening length obeys Lambda = 2 lambda^2/d << a for the following cases: (a) magnetic flux trapped in the hole in the absence of an applied magnetic field, (b) zero magnetic flux in the hole when the ring is subjected to an applied magnetic field, and (c) focusing of magnetic flux into the hole when a magnetic field is applied but no net current flows around the ring. We use a similar method to calculate the magnetic-field and sheet-current distributions and magnetization loops for a thin, bulk-pinning-free superconducting disk (radius b) containing a dome of magnetic flux of radius a when flux entry is impeded by a geometrical barrier.Comment: 10 pages, 13 figure

    Family Involvement in Traumatic Brain Injury Inpatient Rehabilitation: A Propensity Score Analysis of Effects on Outcomes During the First Year After Discharge

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    Objective To evaluate the effect of family attendance at inpatient rehabilitation therapy sessions on traumatic brain injury (TBI) patient outcomes at discharge and up to 9 months postdischarge. Design Propensity score methods are applied to the TBI Practice-Based Evidence database, a database consisting of multisite, prospective, longitudinal, and observational data. Setting Nine inpatient rehabilitation centers in the United States. Participants Patients (N=1835) admitted for first inpatient rehabilitation after an index TBI. Intervention Family attendance during therapy sessions. Main Outcome Measures Participation Assessment for Recombined Tools-Objective-17 (Total scores and subdomain scores of Productivity, Out and About, and Social Relations), Functional Independence Measure, Satisfaction with Life Scale, and Patient Health Questionnaire-9. Results Participants whose families were in attendance for at least 10% of the treatment time were more out and about in their communities at 3 and 9 months postdischarge than participants whose families attended treatment less than 10% of the time. Although findings varied by propensity score method, improved functional independence in the cognitive area at 9 months was also associated with increased family attendance. Conclusions Family involvement during inpatient rehabilitation may improve community participation and cognitive functioning up to 9 months after discharge. Rehabilitation teams should engage patients’ families in the rehabilitation process to maximize outcomes

    Superconducting thin rings with finite penetration depth

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    Recently Babaei Brojeny and Clem [Phys. Rev. B 68, 174514 (2003)] considered superconducting thin-film rings in perpendicular magnetic fields in the ideal Meissner state with negligibly small magnetic penetration depth and presented useful analytical limiting expressions and numerical results for the magnetic-field and sheet-current profiles, trapped magnetic flux, self-inductance, magnetic moment, and focusing of magnetic flux into the hole when no net current flows in the ring. The present paper generalizes all these results to rings with arbitrary values of the two-dimensional effective penetration depth \Lambda = \lambda^2 /d (\lambda is the London depth and d < \lambda/2 the film thickness) using a straightforward matrix inversion method. We also present results for the energy of a superconducting ring as a function of the applied magnetic induction B_a and the quantum number N defining the size of the fluxoid N \phi_0 trapped in the hole.Comment: with 19 figures, gives 11.5 page

    Targets of the Entamoeba histolytica Transcription Factor URE3-BP

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    The Entamoeba histolytica transcription factor Upstream Regulatory Element 3-Binding Protein (URE3-BP) is a calcium-responsive regulator of two E. histolytica virulence genes, hgl5 and fdx1. URE3-BP was previously identified by a yeast one-hybrid screen of E. histolytica proteins capable of binding to the sequence TATTCTATT (Upstream Regulatory Element 3 (URE3)) in the promoter regions of hgl5 and fdx1. In this work, precise definition of the consensus URE3 element was performed by electrophoretic mobility shift assays (EMSA) using base-substituted oligonucleotides, and the consensus motif validated using episomal reporter constructs. Transcriptome profiling of a strain induced to produce a dominant-positive URE3-BP was then used to identify additional genes regulated by URE3-BP. Fifty modulated transcripts were identified, and of these the EMSA defined motif T[atg]T[tc][cg]T[at][tgc][tg] was found in over half of the promoters (54% p<0.0001). Fifteen of the URE3-BP regulated genes were potential membrane proteins, suggesting that one function of URE3-BP is to remodel the surface of E. histolytica in response to a calcium signal. Induction of URE3-BP leads to an increase in tranwell migration, suggesting a possible role in the regulation of cellular motility
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