The post-test analysis of ablative materials Final report, 11 Jul. 1967 - 15 May 1968

Ablative materials examination before and after test firin

Prevalence and risk factors for hepatitis C viral infection amongst a cohort of irish drug users attending a drug treatment centre for agonist opioid treatment (AOT)

Background: Injecting drug use (IDU) is a major driver of the European hepatitis C virus (HCV) epidemic. National data on prevalence of HCV amongst Irish drug users remains confined to certain treatment sites and prison settings. Aim: To examine the prevalence of HCV infection and risk factors associated with infection among the 228 patients attending agonist opioid treatment (AOT) in a clinic in Dublin. Methods: A retrospective cross-sectional study was conducted using data collected from Health Research Board (HRB) forms and standardised written and electronic assessment forms routinely completed on treatment initiation. Results: The prevalence of HCV infection was 63.6% (n= 145) with no significant gender difference (p=0.717). Patients who were infected with HCV were older than those uninfected (41.1 ± 7.5 years versus 37.5 ± 8.5 years; p = 0.001), with prevalence significantly lower in younger adults (p=0.002). Multivariate analysis identified age of first drug use (p=0.002) and first injection (p=0.001), type of first drug used; cannabis (p=0.015), heroin (p=0.014) and cocaine (p=0.018) and early age of AOT entry (p=0.001) as the most significant risk factors for HCV infection in this cohort. Those with no IDU had decreased odds of being HCV positive by 91.1%. Conclusion: Data for this Irish sample indicates high prevalence of HCV infection, and the need to consider age of first drug onset and injecting use, particular drug types and earlier commencement of AOT to inform targeted HCV treatment and prevention interventions in Ireland. © Icro Maremmani

Travelling waves in a drifting flux lattice

Starting from the time-dependent Ginzburg-Landau (TDGL) equations for a type II superconductor, we derive the equations of motion for the displacement field of a moving vortex lattice without inertia or pinning. We show that it is linearly stable and, surprisingly, that it supports wavelike long-wavelength excitations arising not from inertia or elasticity but from the strain-dependent mobility of the moving lattice. It should be possible to image these waves, whose speeds are a few \mu m/s, using fast scanning tunnelling microscopy.Comment: 4 pages, revtex, 2 .eps figures imbedded in paper, title shortened, minor textual change

Brain responses to biological motion predict treatment outcome in young children with autism

Autism spectrum disorders (ASDs) are common yet complex neurodevelopmental disorders, characterized by social, communication and behavioral deficits. Behavioral interventions have shown favorable results—however, the promise of precision medicine in ASD is hampered by a lack of sensitive, objective neurobiological markers (neurobiomarkers) to identify subgroups of young children likely to respond to specific treatments. Such neurobiomarkers are essential because early childhood provides a sensitive window of opportunity for intervention, while unsuccessful intervention is costly to children, families and society. In young children with ASD, we show that functional magnetic resonance imaging-based stratification neurobiomarkers accurately predict responses to an evidence-based behavioral treatment—pivotal response treatment. Neural predictors were identified in the pretreatment levels of activity in response to biological vs scrambled motion in the neural circuits that support social information processing (superior temporal sulcus, fusiform gyrus, amygdala, inferior parietal cortex and superior parietal lobule) and social motivation/reward (orbitofrontal cortex, insula, putamen, pallidum and ventral striatum). The predictive value of our findings for individual children with ASD was supported by a multivariate pattern analysis with cross validation. Predicting who will respond to a particular treatment for ASD, we believe the current findings mark the very first evidence of prediction/stratification biomarkers in young children with ASD. The implications of the findings are far reaching and should greatly accelerate progress toward more precise and effective treatments for core deficits in ASD

Active and driven hydrodynamic crystals

Motivated by the experimental ability to produce monodisperse particles in microfluidic devices, we study theoretically the hydrodynamic stability of driven and active crystals. We first recall the theoretical tools allowing to quantify the dynamics of elongated particles in a confined fluid. In this regime hydrodynamic interactions between particles arise from a superposition of potential dipolar singularities. We exploit this feature to derive the equations of motion for the particle positions and orientations. After showing that all five planar Bravais lattices are stationary solutions of the equations of motion, we consider separately the case where the particles are passively driven by an external force, and the situation where they are self-propelling. We first demonstrate that phonon modes propagate in driven crystals, which are always marginally stable. The spatial structure of the eigenmodes depend solely on the symmetries of the lattices, and on the orientation of the driving force. For active crystals, the stability of the particle positions and orientations depends not only on the symmetry of the crystals but also on the perturbation wavelengths and on the crystal density. Unlike unconfined fluids, the stability of active crystals is independent of the nature of the propulsion mechanism at the single particle level. The square and rectangular lattices are found to be linearly unstable at short wavelengths provided the volume fraction of the crystals is high enough. Differently, hexagonal, oblique, and face-centered crystals are always unstable. Our work provides a theoretical basis for future experimental work on flowing microfluidic crystals.Comment: 10 pages, 10 figure

Hydrochloric Acid Infusion for the Treatment of Metabolic Alkalosis in Surgical Intensive Care Unit Patients

Background: Older reports of use of hydrochloric acid (HCl) infusions for treatment of metabolic alkalosis document variable dosing strategies and risk. Objectives: This study sought to characterize use of HCl infusions in surgical intensive care unit patients for the treatment of metabolic alkalosis. Methods: This retrospective review included patients who received a HCl infusion for \u3e8 hours. The primary end point was to evaluate the utility of common acid-base equations for predicting HCl dose requirements. Secondary end points evaluated adverse effects, efficacy, duration of therapy, and total HCl dose needed to correct metabolic alkalosis. Data on demographics, potential causes of metabolic alkalosis, fluid volume, and duration of diuretics as well as laboratory data were collected. Results: A total of 30 patients were included, and the average HCl infusion rate was 10.5 ± 3.7 mEq/h for an average of 29 ± 14.6 hours. Metabolic alkalosis was primarily diuretic-induced (n = 26). Efficacy was characterized by reduction in the median total serum CO2 from 34 to 27 mM/L (P \u3c 0.001). The change in chloride ion deficit and change in apparent strong ion difference (SIDa) were not correlated with total HCl administered. There were no documented serious adverse effects related to HCl infusions. Conclusion: HCl was effective for treating metabolic alkalosis, and no serious adverse events were seen. In this clinical setting, the baseline chloride ion deficit and SIDa were not useful for prediction of total HCl dose requirement, and serial monitoring of response is recommended

Shift Towards P Limitation with N Deposition?

Atmospheric nitrogen (N) deposition is altering biogeochemical cycling in forests and interconnected lakes of the northeastern US, and may shift nutrient limitation from N toward other essential elements, such as phosphorus (P). Whether this shift is occurring relative to N deposition gradients across the northeastern US has not been investigated. We used datasets for the northeastern US and the Adirondack sub-region to evaluate whether P limitation is increasing where N deposition is high at two geographic scales, based on N:P mass ratios. Using a model- selection approach, we determined that foliar N for dominant tree species and lake dissolved inorganic N (DIN) increased coincident with increasing N deposition, independent of relationships between foliar N or lake DIN and precipitation or temperature. Foliar P also increased with N deposition across the northeastern US for seven of eight deciduous species, but changed less across the Adirondacks. Foliar N:P therefore declined at the highest levels of N deposition for most deciduous species across the region (remaining nearly constant for most conifers and increasing only for black cherry and hemlock), but increased across all species in the Adirondacks. Ratios between DIN and total P (DIN:TP) in lakes were unrelated to N deposition regionally but increased across the Adirondacks. Thus, nutrient limitation patterns shifted from N toward P for dominant trees, and further toward P for predominantly P-limited lakes, at the sub-regional but not regional scale. For the northeastern US overall, accumulated N deposition may be insufficient to drive nutrient limitation from N toward P; alternatively, elements other than P (e.g., calcium, magnesium) may become limiting as N accumulates. The consistent Adirondack foliar and lake response could provide early indication of shifts toward P limitation within the northeastern US, and together with regional patterns, suggests that foliar chemistry could be a predictor of lake chemistry in the context of N deposition across the region

Modelling the reversible uptake of chemical species in the gas phase by ice particles formed in a convective cloud

The present paper is a preliminary study preparing the introduction of reversible trace gas uptake by ice particles into a 3-D cloud resolving model. For this a 3-D simulation of a tropical deep convection cloud was run with the BRAMS cloud resolving model using a two-moment bulk microphysical parameterization. Trajectories within the convective clouds were computed from these simulation outputs along which the variations of the pristine ice, snow and aggregate mixing ratios and concentrations were extracted. The reversible uptake of 11 trace gases by ice was examined assuming applicability of Langmuir isotherms using recently evaluated (IUPAC) laboratory data. The results show that ice uptake is only significant for HNO<sub>3</sub>, HCl, CH<sub>3</sub>COOH and HCOOH. For H<sub>2</sub>O<sub>2</sub>, using new results for the partition coefficient results in significant partitioning to the ice phase for this trace gas also. It was also shown that the uptake is largely dependent on the temperature for some species. The adsorption saturation at the ice surface for large gas mixing ratios is generally not a limiting factor except for HNO<sub>3</sub> and HCl for gas mixing ratio greater than 1 ppbv. For HNO<sub>3</sub>, results were also obtained using a trapping theory, resulting in a similar order of magnitude of uptake, although the two approaches are based on different assumptions. The results were compared to those obtained using a BRAMS cloud simulation based on a single-moment microphysical scheme instead of the two moment scheme. We found similar results with a slightly more important uptake when using the single-moment scheme which is related to slightly higher ice mixing ratios in this simulation. The way to introduce these results in the 3-D cloud model is discussed