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X-ray fluorescence induced by charged particles has been employed in trace element analysis of both animal and human blood, tissue and bone samples. Preparation techniques included microtome slicing and wet digestion in nitric acid, internal chemical standards being used in the latter case.
Most of the specimens arose from a study of interactions between the toxic elements lead and zinc in growing foals; this was motivated by reports of sickness and death in foals raised near lead-zinc smelters. The cause of toxicity in animals from environmental pollution is often attributed to Single factors, whereas in reality interactions among many factors, including a variety of toxic and nutrient trace elements, should be considered.
A variety of spectra are presented and elemental concentrations derived. Agreement between the X-ray data and atomic absorption spectrophotometry is encouraging. The results demonstrate the potential of particle-excited X-ray fluorescenee as a broad-range analytical technique for the study of trace element interactions.
Introduction: Bed boarding of admitted patients in the Emergency Department (ED) is widely recognized as a major contributor to overcrowding, particularly in very high-volume hospitals. The issue of bed boarding is directly tied to hospital-wide capacity, flow and operations. Early morning discharge from inpatient units has been identified as a low-cost intervention to decrease bed boarding, as it allows earlier transfer of admitted patients from the ED. Several hospitals have instituted discharge before noon, or discharge before 10AM policies, practices and targets. Our objectives were 1) to assess the current status of flow within 3 high-volume community hospitals with respect to time of day of discharges from the in-patient units and time of day of transfers from the ED to in-patient units, and 2) to assess the association between time of transfer from the ED and total ED Length of Stay (EDLOS) of admitted patients. Methods: We conducted a retrospective multi-centre observational study during the period of January 1, 2015 to December 31, 2015 at three high-volume community hospitals within Ontario, Canada. All patients admitted to the Medicine service were identified. Time of discharge from the in-patient units and time of transfer from the ED were collected for all patients. EDLOS was calculated for all patients as a function of time of transfer from the ED. Results: Preliminary findings show that, for the three community hospitals, only 11.7% - 19.6% of admitted patients were discharged from the in-patient units during the period between 6AM and 12PM, with a peak discharge time of 2PM in all three hospitals. A concurrent lag was observed in the time of transfer of patients from the ED, with peak transfer times occurring the late afternoon between 3PM and 9PM, and coinciding with a peak in patient volume in the ED. Patients transferred out of the ED earlier in the day (between 12AM 11:59AM) had between 1.4 hours to 8.0 hours lower mean EDLOS when compared to those patients transferred later in the day (between 12PM 11:59PM). Conclusion: Hospital-wide flow and operational issues have a significant impact on ED bed boarding, and potential efficiencies seem at the current time to be underutilized. Interventions aimed at optimizing flow must be implemented alongside those aimed at increasing capacity in order to improve bed boarding. ** These findings are best communicated in graphic form to better represent the dynamics of the flow in and out of the ED over a 24-hour period, and will be presented in graphic format if selected for the conference.
Introduction: Delays in transfer to an in-patient bed of admitted patients boarded in the ED has been identified as one of the chief drivers of ED overcrowding. Our study aims to replicate findings from a previous study in identifying patient characteristics associated with increased boarding time, and the impact of increased boarding time on in-patient length of stay (IPLOS). Methods: We conducted a retrospective single-centre observational study during the period between January 1, 2015 December 31, 2015 at a very high volume community hospital (~ 75,000 ED visits/year). All patients admitted from the ED to Medicine, Pediatrics, Surgery, and Critical Care were identified. The mean time to in-patient bed (TTB), as well as patient-specific and institutional factors that were associated with prolonged boarding times ( 12 hours) were identified. Mean IP LOS was calculated for those with prolonged boarding times and compared to those without prolonged boarding times. Results: There were 8,096 unique admissions during the study period. Patients admitted to the Medicine service exhibited significantly higher boarding times than those admitted to other services, with a mean boarding time of 17.4 hrs, as compared to 4.2 hrs, 5.7 hrs, and 4.0 hrs for those admitted to Surgery, Critical Care and Pediatrics respectively. Within Medicine patients, there was a statistically significant greater odds of prolonged boarding time for patients who were older, had a greater comorbidity burden, and required more specialized in-patient care (i.e. an isolation bed or telemetry bed). Medicine patients with prolonged boarding times also experienced 0.7 days longer IP LOS, even after correcting for age and comorbidity (mean adjusted IP LOS 10.6 days versus 11.3 days). Conclusion: Within our study period, older, sicker patients and those patients requiring more resource-intensive in-patient care have the longest ED boarding times. These prolonged ‘boarding’ times are associated with significantly increased IP LOS.
Theoretical modeling of the daytime Venus ionosphere can be used to augment the measurements of Mariner V made during the 1967 fly-by mission of Venus. The models discussed here are obtained by solving the equations of heat conduction for the electron, ion, and neutral gases along with the momentum and chemical equations for the charged particle densities [1, 2, 3]. When the model is brought into conformity with as much of the data as is possible, constraints can be placed on some of the unknown parameters such as the electron and ion temperatures, and the strength of the magnetic field in the topside Venus ionosphere.
We captured 3-dimensional accelerometry data from the wrists of 116 healthcare professionals as they performed hand hygiene (HH). We then used these data to train a k-nearest-neighbors classifier to recognize specific aspects of HH technique (ie, fingertip scrub) and measure the duration of HH events.
Infect Control Hosp Epidemiol 2014;35(10):1298–1300
Campylobacter is a common but decreasing cause of foodborne infections in the USA. Outbreaks are uncommon and have historically differed from sporadic cases in seasonality and contamination source. We reviewed reported outbreaks of campylobacteriosis. From 1997 to 2008, 262 outbreaks were reported, with 9135 illnesses, 159 hospitalizations, and three deaths. The annual mean was 16 outbreaks for 1997–2002, and 28 outbreaks for 2003–2008. Almost half occurred in warmer months. Foodborne transmission was reported in 225 (86%) outbreaks, water in 24 (9%), and animal contact in seven (3%). Dairy products were implicated in 65 (29%) foodborne outbreaks, poultry in 25 (11%), and produce in 12 (5%). Reported outbreaks increased during a period of declining overall incidence, and seasonality of outbreaks resembled that of sporadic infections. Unlike sporadic illnesses, which are primarily attributed to poultry, dairy products are the most common vehicle identified for outbreaks.
Shock synthesis of nanocrystalline Si, Ge and CdTe was accomplished using high- velocity thermal spray. Si or Ge powders were injected into a high energy flame, created by a thermal spray gun, where the particles melt and accelerate to impact on a substrate. The shock wave generated by the sudden impact of the droplets propagated through the underlying deposits, which induces a phase transition to a high pressure form. The decompression of the high-pressure phase results in the formation of several metastable phases, as evidenced by transmission electron microscopy and x-ray diffraction studies. The peak pressure is estimated to be ≈23GPa with a pulse duration of 1-5 ns. Transmission electron microscopy revealed that the metastable phases of Si with a size range of 2 to 5 nm were dispersed within Si-I. In Ge, a metastable phase, ST-12, was observed. This is a decompression product of Ge-II which possesses the β-Sn type of structure. In the case of CdTe, a fine dispersion of hexagonal CdTe particles, embedded in cubic-CdTe with an average size of 2 nm was obtained.
The focused output from an argon ion laser (514 nm) has been used to pattern micron-size platinum features by decomposition of spun-on metallo-organic film on quartz substrate. The role of laser power and energy density on the thermal decomposition of the film is studied using pulsed and cw laser irradiation. Transient reflectivity has been used as a probe to study the reaction steps involved in the decomposition of the metallo-organic containing film. Preliminary results on the use of the platinum features as seed layer for electroless copper plating is presented.
Electrically conducting palladium features have been produced by laser and ion beam irradiation of thin palladium acetate films. The photothermal reaction induced by scanned continuous wave Ar+ laser irradiation leads to metal lines that may exhibit periodic structure. This results from repeated propagation of “explosive” reaction fronts generated by coupling of the heat from the absorbed laser radiation with the heat of the decomposition reaction of the film. In contrast, 2 MeV He+ ion irradiation produces smooth metallic-looking features that contain up to 20% of the original carbon and 5% of the original oxygen content of the film. Films irradiated with 2 MeV Ne+ ions contain slightly lower amounts of carbon and oxygen residues, but fully exposed thick films (0.90 μm) appear black rather than metallic silver. In addition to having significantly higher purity, the laser-written features have lower resistivities than the ion beam-irradiated features. Infrared spectroscopy of the ion beam-irradiated films as a function of dose indicates a progressive loss in intensity of the characteristics acetate (COO-) vibrations. This occurs at doses lower than those associated with major C and O loss from the films. Partially ion-exposed films continue to decompose to metallic-looking material over a period of weeks after irradiation. Metallic palladium particles apparently catalyze this process.
Oxidation of copper films is carried out using a cw argon ion laser. Time-resolved reflectance measurements during the reaction are performed at probe wavelengths of 632.8 and 514.5 nm. Strong temporal variations in reflectance are observed, and are attributed to interference within the growing oxide film. Measurements carried out as a function of laser power are complemented by Auger electron and scanning electron microscopy. A theoretical model of the system has been developed which treats its optical and thermal properties and the film growth process in an integrated way. The calculations highlight the intimate connection between the time dependence of the optical properties of the metal-metal oxide system and the film growth rate. The highly non-isothermal conditions which prevail account for the rapid rate of oxidation relative to furnace oxidation. Although both laser and furnace oxidation are thermal processes which obey a parabolic rate law, preliminary oxygen pressure dependence data indicate that they may not have the same rate determining step.
Fine conducting features have been produced on Si and SiO2 substrates by irradiation of spin-on palladium acetate, [Pd(O2CCH3)2]3 films with a submicron focused ion beam. The exposures were made with a 20 keV Ga+, focused to a 0.2 micrometer spot. Electrical conductivity measuremnents were made on the resultant features as a function of ion dose for linewidths of one and ten micrometers. The sheet conductivity in the two cases was comparable and increased dramatically in the dose range between 2×1014 and 5×1014 ions/cm2. The conductivity of the exposed lines was further increased after heating in a hydrogen atmosphere. Measurements of carbon and oxygen content indicate that even at the highest ion doses a significant amount of organic material remains. Results are compared to those for 2 MeV He+ and Ne+ broad beam exposures. Potential applications are also discussed.
Soft x-ray core-level photoemission was used to study the reaction layer formed on a Si(111) surface during steady-state etching by XeF2. These surfaces show shifted Si 2p core levels which correspond to particular silicon fluoride species residing in the reaction layer. Spectra were collected in constant final state (CFS) mode for electron kinetic energies ranging from 2 eV to 90 eV. The use of CFS mode allowed the electron escape length to remain constant during individual spectra. The electron escape length for the reaction layer as a function of kinetic energy was then determined by monitoring the intensity of the bulk silicon signal. Thus, by analyzing the proportions of each silicon fluoride species observed in the individual CFS spectra as a function of the electron escape depth in the reaction layer, the distribution of the silicon fluoride species in the layer was obtained. The distribution determined placed SiF at the interface between the reaction layer and the bulk silicon, and the remaining species, SiF2, SiF3 and SiF4, successively layered on top. This observation leads to a model for the structure of the reaction layer.
High Tc superconducting thin films have been deposited on sapphire by means of RF‐sputtering from a single stoichiometric target of YBa2Cu3O7‐x composition. The YBa2Cu3O7‐x films were deposited in an argon‐oxygen atmosphere on a substrate which reached a temperature of s 400°C during deposition. The study of stoichiometry and homogeneity of the as‐deposited films, by means of electromicroprobe analysis (EMPA), was used to optimize the sputtering parameters of the system. To achieve superconductivity, with an onset of s 90 K, a high‐temperature, post‐deposition thermal treatment in oxygen was necessary. Resistivity measurements show that, with respect to the bulk samples, zero resistivity is lowered as a result of substrate interaction. The use of buffer layers can improve the quality of the superconducting thin films.
AℓN deposited by D.C. triode sputtering and spin-on, phosphorus-doped glass (PSG) layers on GaAs and InP were investigated as encapsulants. These films have similar expansion coefficients to both GaAs and InP, minimizing the amount of strain induced in the near-surface region of the underlying wafer. We have quantified this effect by direct measurements of the stress in the films and by using secondary ion mass spectrometry profiling to measure the redistribution of Cr and Fe in encapsulated GaAs and InP respectively during high temperature processing. The dopant redistribution is considerably less for the AℓN and PSG films compared to the more conventional SiO2 and Si3N4 layers. The interaction of the films with the substrate at elevated temperatures is minimal as determined by Auger profiling and the electrical properties of the surface after removal of the encapsulants. The composition of the films remains essentially constant after annealing, as measured by Rutherford backscattering, and the thickness uniformity over large wafer diameters (2″) can be excellent with close control of the deposition parameters. The activation characteristics of low dose, Si-implanted layers in GaAs using either PSG or AℓN are comparable to those obtained using capless annealing or SiO2 or Si3N4 encapsulation.