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Peripherally inserted central catheters (PICCs) are a mainstay of nonpermanent vascular access devices. In this study, we assessed patients displaying anaphylaxis or anaphylactoid reactions to the PowerPICC SOLO and Groshong PICC (Bard Access Systems) using the Sherlock tip locating system (TLS).
Patients from 2 tertiary-care hospitals were systematically monitored over 4 years for adverse events following the insertion of a PICC using the Sherlock TLS. Insertion data were also collected using the BioFlo PICC (Angiodynamics)from a third hospital site and from The Ottawa Hospital over 4 years as an additional comparator. Three definitions of anaphylaxis and anaphylactoid reactions were utilized, and the Cohen κ was used to assess interrater agreement. Analysis of reactions among the patient cohorts was performed using the χ2 test with Yates correction or the Fisher exact test as appropriate.
Among 8,257 insertions using the TLS PICCs, 37 potential reactions (0.45%) were recorded. Using specific definitions for anaphylaxis or anaphylactoid reactions, 54.1%–91.9% met criteria. Comparator populations using data from Calgary (n = 491) and Ottawa (n = 7,889) using the BioFlo PICC insertion found no reactions. Anaphylactic or anaphylactoid reactions were significantly associated with the PowerPICC SOLO and Groshong PICC with the TLS compared to the BioFlo PICC (P < .0001) across all definitions. The largest subset of patients experiencing adverse reactions had cystic fibrosis (CF) (n = 4, 10.8%).
Our study results demonstrate significant adverse events associated with the PowerPICC SOLO and Groshong PICC using the Sherlock TLS inserted across a range of patient populations. The incidence rate of anaphylaxis or anaphylactoid reactions in the CF population at our center is significantly higher than in non-CF patients (P < .001).
In 2011 the Incidence Assay Critical Path Working Group reviewed the current state of HIV incidence assays and helped to determine a critical path to the introduction of an HIV incidence assay. At that time the Consortium for Evaluation and Performance of HIV Incidence Assays (CEPHIA) was formed to spur progress and raise standards among assay developers, scientists and laboratories involved in HIV incidence measurement and to structure and conduct a direct independent comparative evaluation of the performance of 10 existing HIV incidence assays, to be considered singly and in combinations as recent infection test algorithms. In this paper we report on a new framework for HIV incidence assay evaluation that has emerged from this effort over the past 5 years, which includes a preliminary target product profile for an incidence assay, a consensus around key performance metrics along with analytical tools and deployment of a standardized approach for incidence assay evaluation. The specimen panels for this evaluation have been collected in large volumes, characterized using a novel approach for infection dating rules and assembled into panels designed to assess the impact of important sources of measurement error with incidence assays such as viral subtype, elite host control of viraemia and antiretroviral treatment. We present the specific rationale for several of these innovations, and discuss important resources for assay developers and researchers that have recently become available. Finally, we summarize the key remaining steps on the path to development and implementation of reliable assays for monitoring HIV incidence at a population level.
Introduction: Bronchiolitis is the most common lower respiratory tract infection among infants, characterized by wheeze and respiratory distress. Reliance on pulse oximetry has been associated with increased hospitalizations, prolonged hospital stay and escalation of care. The objectives were to determine if there is a difference in the proportion of unscheduled medical visits within 72 hours of emergency department discharge in infants with bronchiolitis who desaturate to <90% for at least one minute during home oximetry monitoring versus those without desaturations. Methods: This is a prospective cohort study from 2008 to 2013 enrolling 118 otherwise healthy infant aged 6 weeks to 12 months discharged home from a tertiary care pediatric emergency department with a diagnosis of acute bronchiolitis. The primary outcome was unscheduled medical visits for bronchiolitis, a visit to any health care provider due to concerns about respiratory symptoms, within 72 hours of discharge in infants with and without desaturations. Secondary outcomes included examination of the severity and duration of the desaturations, delayed hospitalizations within 72 hours of discharge and the effect of activity on desaturations. Results: During a mean monitoring period of 19 hours, 75/118 (64%) infants had at least one desaturation event (median continuous duration 3.4 minutes). 59/118 infants (50%) had at least 3 desaturations, 12 (10%) desaturated for >10% monitored time and 51(43%) had desaturations lasting ≥ 3 minutes continuously. 59/118 (50%) infants desaturated to ≤ 80% and 29 (24%) to ≤ 70% for ≥ 1 minute. A total 18/75 infants with desaturations (24.0%) had an unscheduled visit for bronchiolitis versus 11/43 of their non-desaturating counterparts (25.6%) [Difference - 1.6%; 95%CI -0.15 to ∞, p=0.66]. One of 75 desaturating infants (1.3%) and 2/43 (4.6%) of those without desaturations were hospitalized within 72 hours [Difference of -3.3%; 95% CI -0.04 to 0.10, p = 0.27]. Seventy seven percent of infants with desaturations experienced them during sleep or while feeding. Conclusion: The majority of infants with mild bronchiolitis experienced recurrent or sustained desaturations after discharge home. Children with and without desaturations had comparable rates of return for care, with no difference in unscheduled return medical visits and delayed hospitalizations.
It is shown that the Moon possesses an extraordinary response to induction from the solar wind due to a combination of a high interior electrical conductivity together with a relatively resistive crustal layer into which the solar wind dynamic pressure forces back the induced field. The dark side
response, devoid of solar wind pressure, is approximately that expected for the vacuum case. These data permit an assessment of the interior conductivity and an estimate of the thermal gradient in the crustal region. The discovery of a large permanent magnetic field at the Apollo 12 site corresponds approximately to the paleomagnetic residues discovered in both Apollo 11 and 12 rock samples The implications regarding an early lunar magnetic field are discussed and it is shown that among the various conjectures regarding the early field the most prominent are either an interior dynamo or an early approach to the Earth though no extant model is free of difficulties.
In order to manufacture organic electronic devices with high performance, more detailed studies of the structure and the morphology of the organic materials as well as the underlying physical charge transport mechanisms are warranted. For instance, high efficiency organic thin film transistors (OTFTs) require materials with high charge carrier mobility [1, 2]. The parameters that determine the charge carrier mobility of the device include the structure of the first organic layer at the organic-dielectric interface as well as the morphology and the structural order of the other organic layers. Therefore, fundamental questions about structural properties of organic materials should be answered in order to optimize device performance [2-4].
In this work, several bilayer structures of LiF/PTCDI-C8 and LiF/pentacene were prepared and their morphology and molecular structure were characterized using X-ray reflectivity (XRR) technique. In order to study the effects of the films’ structures and dielectric/organic interfacial properties on the device performance, OTFTs based on these bilayers were fabricated and characterized. It has been observed that PTCDI-C8 thin films have higher molecular packing in the LiF/PTCDI-C8 bilayer structure, which results in superior electrical characteristics for OTFTs based on this organic material. Devices with LiF/PTCDI-C8 bilayer exhibit about one order of magnitude higher output current (Ids) at a constant drain-source voltage (Vds) compared to the devices with LiF/pentacene bilayer. The observed differences in the electrical characteristics of these devices can be attributed to the effects of the dielectric/organic interface and the molecular structure of the organic layers.
We have produced thin film composite matrices containing granular transition metals in the zero valent state and have found onset of percolation at a much lower volume fraction than was the case for Au, albeit for significantly smaller transition metal particles. At volume fractions below percolation these granular composites are superparamagnetic down to 6°K. Remanent magnetization and hysteretic ferromagnetic behavior was not observed until we were slightly above the onset of electrical percolation. We interpret this result as indicative of ferromagnetic ordering among the transition metal grains. No significant reduction in magnetic moment due to size effects or to chemical interaction with the matrix was observed. A very small size dispersion of the metal clusters was indicated both from magnetic a well as electron microscopy measurements.
The intermetallic compound NiTi was cold rolled at room temperature. Amorphous bands were formed within the finely twined crystalline matrix after thickness reduction of 60%. Striking similarities were observed in microstructural morphology between amorphous bands and shear bands that are generally observed in heavily cold-rolled pure metals. We suggest from the present observations together with the reported results in other solid-state amorphization experiments that the amorphous bands are produced in the shear bands, and that amorphization is caused by mechanical instability against the shear stress.
This paper reports on the structures and properties of Y1Ba2Cu3O9−x samples prepared in precisely controlled oxygen environments using a solid-state ionic technique. By titrating out oxygen at low temperatures, orthorhombic Y1Ba2Cu3O9−x samples were prepared with oxygen contents below 6.50. Resistivity and magnetometry studies indicated that these reduced, orthorhombic samples were marginally superconducting, with their superconductivity probably arising from local regions of higher oxygen content.
.We report the growth and magnetic properties of epitaxial Fe films, prepared by MBE on films of GaAs and In0.2Ga0.8As, on GaAs (100) substrates. We find that the magnetic properties of the Fe films, which are in the thickness range 300-900Å have virtually no dependence on the nature of the buffer film between the GaAs substrate and the Fe film. In terms of FMR linewidth, 4πMs and anisotropy, the Fe films are of the highest quality yet reported. Values of exchange constant and surface anisotropies were derived from an analysis of spinwaves observed in the thickest films.
We report on a novel promising technique for the investigation of magnetic structures at surfaces at high spatial resolution, ultimately down to the atomic scale. This technique is based on the observation of vacuum tunneling of spin-polarized electrons by means of a scanning tunneling microscope (STM). We discuss appropriate probe tips for the spin-polarized STM (SPSTM) and describe initial experimental results. We further focus on the information obtained by SPSTM. Finally, the perspectives of SPSTM will be discussed.
We have investigated the magnetic order, using SQUID magnetometry, for short modulation wavelength Fe3O4/NiO superlattices, grown on single crystal MgO. Ferrimagnetic Fe3O4 has a saturation moment of ~500 emu/cm3 at 0 K and a Curie temperature of 858 K, while bulk NiO is antiferromagnetic with a NMel temperature of 525 K. Very high crystalline quality with little interdiffusion is indicated by X-ray diffraction, SEM, optical microscopy, and in-situ RHEED, and the samples show highly anisotropic electrical conductivity which also indicates the strong modulation present. Long wavelength samples (Amod > 200 Å) have a behavior only slightly different from that expected from bulk Fe3O4, but for Amod<80 Å, spontaneous magnetization is replaced by paramagnetism, with weak temperature dependence (not I/T) from 5 K to 400 K.
We report structural and magnetic X-ray scattering measurements of a 2000Å thick Dy film, sandwiched by LaF3 films on a GaAs(111) substrate. The structure was grow by molecular beam epitaxy with the c-axis of the Dy parallel to the LaF3 c-axis and GaAs axis. For the magnetic X-ray scattering, we used a polarization analyzer and an X-ray energy near the Dy L111 absorption edge. ∆t this energy there is a resonant enhancement in the magnetic scattering intensity, and we obtained ≃-50 counts per second in the magnetic diffraction peaks.
Between 85 and 179K, bulk Dy forms a helical antiferromagnetic structure, and below 85K, it transforms into a ferromagnet. We find that the c-axis lattice constant of the Dy film has a similar temperature dependence to bulk Dy from room temperature to about 110K, but below this, the film behaves differently from bulk and is strained. The temperature dependence of the turn-angle in the helical antiferromagnetic state is similar to bulk, although a weaker dependence is observed below ∼1 10K due to magnetoelastic effects. Surprisingly, the magnetic coherence length (≃310Å) is significantly shorter than the structural coherence length (≃730Å). The transition to ferromagnetic ordering at 86K exhibits temperature hysteresis as is evident in the structural and magnetic X-ray data and in SQUID magnetometry data. We believe this hysteresis arises from a combination of the strain-energy barrier accompanying the transition and magnetic inhomogeneities in the film.
We summarize results of our recent theoretical studies of spin dependent scattering of electrons from ferromagnetic surfaces. We obtain an excellent account of both the energy and angle variation of the exchange asymmetry reported by Waller and Gradmann in their SPLEED study of the Fe(110) surface, and of spin dependent asymmetries in the transmission of photoelectrons through an ultra thin film of Fe on Cu(100). Potentials supplied by Fu and Freeman enable us to account for the data, with use of ground state potentials generated by ab initio methods.
Spin polarized photoemission is used to study the magnetic states associated with the clean iron (001) surface. These studies reveal evidence for a minority spin surface state in agreement with a first principles calculation. Studies of the same surface with silver and chromium epitaxial overlayers reveal evidence for interface states derived from this state found on the clean surface. In the case of the silver overlayer the binding energy of the new state is found to be dependent on the layer by layer thickness of the overlayer. With chromium overlayers the binding energy for the same interface state does not show the same thickness dependence. However a second interface state is observed immediately below the Fermi level. These changes in the interfacial electronic structure have implications for any modelling of magnetic coupling in multilayers dependent on the magnetic properties of the interface.
We find that epitaxial Fe films sandwiched between epitaxial Ag films grown on GaAs (001) substrates possess residual coherency strain at a thickness of 2000Å. The  directions of the Fe and Ag films are tilted with respect to the GaAs  axis. The tilts are coplanar with the tilt of the substrate surface normal to the  axis of GaAs and are qualitatively consistent with a recently proposed modol for tilted epitaxy.
The growth by sputtering of a series of thin films of Fe/Au on MgO(001) substrates was analyzed using Bragg and diffuse X-ray scattering. The Fe (bcc) layer grows rotated by 45° with respect to the MgO – Au(fcc) (001) epitaxial orientation, resulting in an almost perfect match between the two metallic structures. By collecting the X-ray diffuse scattering under grazing incidence using a 2-dimensional image plate detector, we mapped the reciprocal space of these films. We characterized the correlated interface roughness starting with a buffer of Fe in which only three interfaces are present. The propagation of the roughness was subsequently characterized for Fe/Au multilayers with 40 and 100 bilayers. We observe an enlargement of the surface features as a function of time, evidenced by the longer lateral cutoff length measured for thicker films.
A systematic study on magnetic properties of (Fc/Pt) compositionally-modulated films as a function of substrate-deposition-temperature has been carried out. For films with (2.5ÅFe/18ÅPt)×40, the intrinsic perpendicular magnetic anisotropy Ku is found to increase with decreasing temperature for all the sarmples deposited at temperatures from -114 °C to 220°C during deposition. The higher the substrate-deposition-temperature, the larger the Ku values become. This result implies a possible contribution from the magne to-elastic effect to the total anisotropy. However, a major part responsible for the perpendicular anisotropy may be found in other mechanisms. The saturation magnetization is found to exceed the value for pure Fe at temperatures lower than 180K.
Fe/Au and Fe/Ag films grown on MgO(001) oriented substrates exhibit the same in-plane epitaxy since Au and Ag have the same fcc bulk structure and nearly equivalent lattice parameters. Using synchrotron X-ray reflectivity and high-angle Bragg scattering we show that Fe(15Å)/Au(21Å) multilayers grown by sputtering exhibit different profiles for Fe/Au and Au/Fe interfaces. We analyze this in view of the action of Au as a surfactant during the growth of Fe. Similar Fe/Ag multilayers have considerably worse interfacial quality since Fe and Ag do not interdiffuse, and this leads to the result that the interfaces cannot be described by error function profiles. Using non-specular x-ray reflectivity we show that whereas Fe/Au interfaces are self-affine, Fe/Ag interfaces exhibit two regimes of scaling behavior as a function of spatial wavelength. This suggests that two different mechanisms are important in describing the growth of Fe/Ag films.