Comparing Intubation Success Between Flight Nurses and Flight Paramedics in Helicopter Emergency Medical Services.

OBJECTIVE: Intubation is a vital skill performed by flight nurses and paramedics. Before flight training, nurses do not routinely intubate and must be trained in proper techniques. Flight paramedics universally train in intubation before flight training and are the primary managers of in-flight airways. The aim of this study was to determine if a difference exists in intubation attempts and success rates between flight nurses and flight paramedics. METHODS: A 5-year retrospective chart review was performed from a regional helicopter emergency medical service. Intubation attempts and the success of flight nurses compared with flight paramedics were the primary outcomes. RESULTS: Three hundred three of 322 cases in which intubation was attempted were successful. Three hundred forty-four total intubation attempts were made. Two hundred seventy-one (88.9%) patients were intubated by paramedics, and 32 (10.5%) were intubated by nurses. Of the 19 unsuccessfully intubated patients, 14 (73.7%) were attempted by a paramedic and 5 (26.3%) by a nurse. Two hundred seventy-seven intubations were successful on the first attempt, 250 (90.3%) of which were performed by a paramedic and 27 (9.7%) by a nurse. CONCLUSION: Flight paramedics performed more intubations with greater success than flight nurses.

Direct Observation of PFIB-Induced Clustering in Precipitation-Strengthened Al Alloys by Atom Probe Tomography.

The effect of sample preparation on a pre-aged Al­Mg­Si­Cu alloy has been evaluated using atom probe tomography. Three methods of preparation were investigated: electropolishing (control), Ga+ focused ion beam (FIB) milling, and Xe+ plasma FIB (PFIB) milling. Ga+-based FIB preparation was shown to introduce significant amount of Ga contamination throughout the reconstructed sample (≈1.3 at%), while no Xe contamination was detected in the PFIB-prepared sample. Nevertheless, a significantly higher cluster density was observed in the Xe+ PFIB-prepared sample (≈25.0 × 1023 m−3) as compared to the traditionally produced electropolished sample (≈3.2 × 1023 m−3) and the Ga+ FIB sample (≈5.6 × 1023 m−3). Hence, the absence of the ion milling species does not necessarily mean an absence of specimen preparation defects. Specifically, the FIB and PFIB-prepared samples had more Si-rich clusters as compared to electropolished samples, which is indicative of vacancy stabilization via solute clustering.

Charge-State Field Evaporation Behavior in Cu(V) Nanocrystalline Alloys.

Atom probe tomography (APT) of a nanocrystalline Cu-7 at.% V thin film annealed at 400°C for 1 h revealed chemical partitioning in the form of solute segregation. The vanadium precipitated along high angle grain boundaries and at triple junctions, determined by cross-correlative precession electron diffraction of the APT specimen. Upon field evaporation, the V2+/(V1+ + VH1+) ratio from the decomposed ions was ~3 within the matrix grains and ~16 within the vanadium precipitates. It was found that the VH1+ complex was prevalent in the matrix, with its presence explained in terms of hydrogen's ability to assist in field evaporation. The change in the V2+/(V1+ + VH1+) charge-state ratio (CSR) was studied as a function of base temperature (25-90 K), laser pulse energy (50-200 pJ), and grain orientation. The strongest influence on changing the CSR was with the varied pulse laser, which made the CSR between the precipitates and the matrix equivalent at the higher laser pulse energies. However, at these conditions, the precipitates began to coarsen. The collective results of the CSRs are discussed in terms of field strengths related to the chemical coordination.

The Influence of Isoconcentration Surface Selection in Quantitative Outputs from Proximity Histograms.

Isoconcentration surfaces are commonly used to delineate phases in atom probe datasets. These surfaces then provide the spatial and compositional reference for proximity histograms, the number density of particles, and the volume fraction of particles within a multiphase system. This paper discusses the influence of the isoconcentration surface selection value on these quantitative outputs, using a simple oxide dispersive strengthened alloy, Fe91Ni8Zr1, as the case system. Zirconium reacted with intrinsic oxygen impurities in a consolidated ball-milled powder to precipitate nanoscale zirconia particles. The zirconia particles were identified by varying the Zr-isoconcentration values as well as by the maximum separation data mining method. The associated outputs mentioned above are elaborated upon in reference to the variation in this Zr isosurface value. Considering the dataset as a whole, a 10.5 at.% Zr isosurface provided a compositional inflection point for Zr between the particles and matrix on the proximity histogram; however, this value was unable to delineate all of the secondary oxide particles identified using the maximum separation method. Consequently, variations in the number density and volume fraction were observed as the Zr isovalue was changed to capture these particles resulting in a loss of the compositional accuracy. This highlighted the need for particle-by-particle analysis.

Can Physicians Demonstrate High Quality Care Using Paternalistic Practices? A Case Study of Paternalism in Latino Physician-Patient Interactions.

We argue that patient autonomy is a cultural value specific to Western culture and that the autonomy focus in U.S. health care may produce negative patient outcomes for patients from other cultures. To this end, we present a case study of a Mexican physician's interactions with his patients and apply the method of discourse analysis to argue that (a) this physician's interactions are highly paternalistic, (b) there is an appreciation for this among his Latino patients and in the broader Latino community, and (c) this physician provides high-quality ethical care precisely because his paternalism communicates important ethical values such as familial intimacy, insistence, and care. We further propose that paternalism may produce better outcomes for Latino patients.

Bonding effects on the slip differences in the B1 monocarbides.

Differences in plasticity are usually attributed to significant changes in crystalline symmetry or the strength of the interatomic bonds. In the B1 monocarbides, differences in slip planes exist at low temperatures despite having the same structure and very similar bonding characteristics. Our experimental results demonstrate concretely that HfC slips on {110} planes while TaC slips on {111} planes. Density functional theory calculations rationalize this difference through the formation of an intrinsic stacking fault on the {111} planes, formation of Shockley partials, and enhanced metallic bonding because of the valence filling of electrons between these transitional metal carbides.

Biological control of mosquitoes in scrap tires in Brownsville, Texas, USA and Matamoros, Tamaulipas, Mexico.

Dengue periodically circulates in southern Texas and neighboring Tamaulipas, Mexico; thus, a closer examination of human and vector ecology at the northern limits of North American transmission may improve prevention activities. Scrap tires produce large mosquito populations and increase the risk of dengue transmission. Some households choose not to pay tire disposal fees, and many tires are illegally dumped in residential areas. Biological control may provide low-cost and environmentally friendly mosquito control. This pilot study evaluated the ability of Mesocyclops longisetus to reduce mosquito populations in existing residential scrap tire piles. Mosquito populations were measured by the number of all mosquito pupae within tires or adult Aedes aegypti and Ae. albopictus near piles. Mesocyclops longisetus treated piles did not significantly reduce total mosquito pupae (P = 0.07) in Matamoros, Mexico. The study also evaluated the efficacy of native Toxorhynchites moctezuma which preferentially colonized tire piles under vegetation cover in Brownsville, TX. Toxorhynchites moctezuma larvae significantly reduced total mosquito pupae, but the strength of control diminished over time.

Cultural Differences in Patients' Preferences for Paternalism: Comparing Mexican and American Patients' Preferences for and Experiences with Physician Paternalism and Patient Autonomy.

Following up on previous research demonstrating the high level of care realized by a paternalistic Mexican physician, the present research further explored the hypothesis that there are cultural differences in preferences for and experiences with physician paternalism vs. patient autonomy in White American culture as compared with Mexican culture. In this research, we interviewed sixty (60) people including twenty (20) Mexican, twenty (20) Mexican American, and twenty (20) White American respondents. We asked these patients about their experiences with and attitudes towards paternalism and patient autonomy in healthcare interactions. With some caveats, our data showed strong support for both hypotheses while also suggesting a high level of care can be realized by paternalistic physicians when "paternalism" is understood in a cultural context. We close with a brief consideration of the implications of these findings.

Dynamical diffraction simulations in FePt--I.

A series of multislice simulations to quantify the effect of various degrees of order, composition, and thickness on the electron diffracted intensities were performed using the L10 FePt system as the case study. The dynamical diffraction studies were done in both a convergent electron beam diffraction and selected area electron diffraction condition. The L10 symmetry demonstrated some peculiar challenges in the simulation, in particular between the {111} plane normal and the <111> direction, which are not equivalent because of tetragonality. A hybrid weighting function atom of Fe-Pt was constructed to account for S < 1 or nonequiatomic compositions. This statistical approach reduced the complexity of constructing a crystal with the probability that a particular atom was at a particular lattice site for a given order parameter and composition. Considerations of accelerating voltage, convergent angle, and thermal effects are discussed. The simulations revealed significant differences in intensity ratios between films of various compositions but equivalent unit cell numbers and degree of order.

Comparison of simulated and experimental order parameters in FePt--II.

Eight FePt thin film specimens of various thicknesses, compositions, and order parameters have been analyzed to determine the robustness and fidelity of multislice simulations in determining the chemical order parameter via electron diffraction (ED). The shape of the simulated curves depends significantly on the orientation and thickness of the specimen. The ED results are compared to kinematical scattering order parameters, from the same films, acquired from synchrotron X-ray diffraction (XRD). For the specimens analyzed with convergent beam electron diffraction conditions, the order parameter closely matched the order parameter as determined by the XRD methodology. However, the specimens analyzed by selected area electron diffraction conditions did not show good agreement. This has been attributed to substrate effects that hindered the ability to accurately quantify the intensity values of the superlattice and fundamental reflections.

Modeling transit bus fuel consumption on the basis of cycle properties.

A method exists to predict heavy-duty vehicle fuel economy and emissions over an "unseen" cycle or during unseen on-road activity on the basis of fuel consumption and emissions data from measured chassis dynamometer test cycles and properties (statistical parameters) of those cycles. No regression is required for the method, which relies solely on the linear association of vehicle performance with cycle properties. This method has been advanced and examined using previously published heavy-duty truck data gathered using the West Virginia University heavy-duty chassis dynamometer with the trucks exercised over limited test cycles. In this study, data were available from a Washington Metropolitan Area Transit Authority emission testing program conducted in 2006. Chassis dynamometer data from two conventional diesel buses, two compressed natural gas buses, and one hybrid diesel bus were evaluated using an expanded driving cycle set of 16 or 17 different driving cycles. Cycle properties and vehicle fuel consumption measurements from three baseline cycles were selected to generate a linear model and then to predict unseen fuel consumption over the remaining 13 or 14 cycles. Average velocity, average positive acceleration, and number of stops per distance were found to be the desired cycle properties for use in the model. The methodology allowed for the prediction of fuel consumption with an average error of 8.5% from vehicles operating on a diverse set of chassis dynamometer cycles on the basis of relatively few experimental measurements. It was found that the data used for prediction should be acquired from a set that must include an idle cycle along with a relatively slow transient cycle and a relatively high speed cycle. The method was also applied to oxides of nitrogen prediction and was found to have less predictive capability than for fuel consumption with an average error of 20.4%.

Improved computational method to generate properly equilibrated atomistic microstructures.

Atomistic simulations play an important role in unravelling the fundamental behavior of nanocrystalline (NC) metals/alloys. To ensure the validity of the simulated results, the initial NC structures must be representative of a real material to the extent possible. Using proper equilibration techniques, it must also be ensured that these NC structures reach a state of metastable equilibrium before probing their response. To this effect, the influence of simulated thermal equilibration of atomistic NC Ni structures on the resulting mechanical behavior is discussed in this work. It is shown that the well-equilibrated NC structures become stiffer in terms of both elastic response and yielding behavior and accumulate less residual strain upon unloading, thus, signifying the importance of proper equilibration. However, it is found that the regular equilibration method of thermal relaxations at 300 K, typically employed in atomistic modeling studies, takes significantly longer to drive the NC structures towards a metastable equilibrium state. Finally, an improved two-step equilibration method is presented that drastically expedites the equilibration process while resulting in the structural and mechanical properties comparable with the regular equilibration method performed for significantly larger simulation times. The major modification in the improved method involves:•Subjecting only the grain boundary and the surrounding atoms to thermal relaxations at relatively higher temperature.

Thermodynamics of the DNA structural selectivity of the Pol I DNA polymerases from Escherichia coli and Thermus aquaticus.

Understanding the thermodynamics of substrate selection by DNA polymerase I is important for characterizing the balance between replication and repair for this enzyme in vivo. Due to their sequence and structural similarities, Klenow and Klentaq, the large fragments of the Pol I DNA polymerases from Escherichia coli and Thermus aquaticus, are considered functional homologs. Klentaq, however, does not have a functional proofreading site. Examination of the DNA binding thermodynamics of Klenow and Klentaq to different DNA structures: single-stranded DNA (ss-DNA), primer-template DNA (pt-DNA), and blunt-end double-stranded DNA (ds-DNA) show that the binding selectivity pattern is similar when examined across a wide range of salt concentration, but can significantly differ at any individual salt concentration. For both proteins, binding of single-stranded DNA shifts from weakest to tightest binding of the three structures as the salt concentration increases. Both Klenow and Klentaq release two to three more ions when binding to pt-DNA and ds-DNA than when binding to ss-DNA. Klenow exhibits significant differences in the Delta C(p) of binding to pt-DNA versus ds-DNA, and a difference in pI for these two complexes, whereas Klentaq does not, suggesting that Klenow and Klentaq discriminate between these two structures differently. Taken together, the data suggest that the two polymerases bind ds-DNA very differently, but that both bind pt-DNA and ss-DNA similarly, despite the absence of a proofreading site in Klentaq.

Expressing cycles and their emissions on the basis of properties and results from other cycles.

A method is proposed to predict vehicle emissions over a driving cycle on the basis of the vehicle's emissions measured over other driving cycles and the properties of these cycles. These properties include average velocity, average inertial power, and average acceleration. This technique was demonstrated and verified using data from the Coordinating Research Council (CRC) E-55/59 emissions inventory program using the statistical properties of the cycles used for measurement in E-55/59. These cycles were Idle mode, Creep mode, Cruise mode, and Transient mode of the 5-Mode CARB H-HDDT, and their intensive properties were average velocity, average acceleration, and average inertial power. The predicted emissions were from the vehicle driven over the U.S. heavy-duty urban dynamometer driving schedule (UDDS). The emissions data were collected from 56 heavy-duty trucks operating at a test weight of 56000 lbs. The predicted emissions data for the UDDS can be expressed as a linear combination of emissions from Idle, Transient, and Cruise modes, and the weighting factors for the linear combination can be determined without prior knowledge of the UDDS emissions themselves. Different combinations of cycles were employed to predict UDDS emissions, and the combination of Idle, Transient, and Cruise modes was found to be the most suitable. For the 56 heavy-duty trucks, the coefficient of determination (R2) in predicting carbon dioxide (CO2) was 0.80, oxides of nitrogen (NOx) was 0.89, and total particulate matter (PM) was 0.71. The average errors between the predicted and measured cycle emissions were 4.2%, 7.8%, and 46.8%, respectively. As with most emissions modeling tools, CO2 and NOx were better predicted than PM. The generic use of the technique was further demonstrated by predicting the emissions expected to arise from operation over the European Transient Cycle (ETC).

Idle emissions from medium heavy-duty diesel and gasoline trucks.

Idle emissions data from 19 medium heavy-duty diesel and gasoline trucks are presented in this paper. Emissions from these trucks were characterized using full-flow exhaust dilution as part of the Coordinating Research Council (CRC) Project E-55/59. Idle emissions data were not available from dedicated measurements, but were extracted from the continuous emissions data on the low-speed transient mode of the medium heavy-duty truck (MHDTLO) cycle. The four gasoline trucks produced very low oxides of nitrogen (NOx) and negligible particulate matter (PM) during idle. However, carbon monoxide (CO) and hydrocarbons (HCs) from these four trucks were approximately 285 and 153 g/hr on average, respectively. The gasoline trucks consumed substantially more fuel at an hourly rate (0.84 gal/hr) than their diesel counterparts (0.44 gal/hr) during idling. The diesel trucks, on the other hand, emitted higher NOx (79 g/hr) and comparatively higher PM (4.1 g/hr), on average, than the gasoline trucks (3.8 g/hr of NOx and 0.9 g/hr of PM, on average). Idle NOx emissions from diesel trucks were high for post-1992 model year engines, but no trends were observed for fuel consumption. Idle emissions and fuel consumption from the medium heavy-duty diesel trucks (MHDDTs) were marginally lower than those from the heavy heavy-duty diesel trucks (HHDDTs), previously reported in the literature.

Development of a heavy heavy-duty diesel engine schedule for representative measurement of emissions.

The Advanced Collaborative Emissions Study (ACES) has the objective of characterizing the emissions and assessing the possible health impacts of the 2007-2010 heavy-duty diesel engines and their control systems. The program seeks to examine emissions from engines operated in a realistic duty cycle and requires the development of an engine test schedule described in this paper. Field data on engine operation were available from Engine Control Unit (ECU) broadcasts from seven heavy heavy-duty trucks (HHDDT) tested during the Coordinating Research Council (CRC) E-55/59 study. These trucks were exercised at three weights (30,000 lb [13,610 kg], 56,000 lb [25,400 kg], and 66,000 lb [29,940 kg]) through four different active modes of a chassis test schedule that were developed from the data of in-use HHDDT operation in the state of California. The trucks were equipped with heavy-duty engines made by three major U.S. engine manufacturers with a range of model years from 1998 to 2003. This paper reports on the development of four engine test modes, termed creep, transient, cruise, and high-speed cruise (HHDDT_S), which correspond to the E-55/59 HHDDT chassis test modes. The creep and transient modes represent urban travel, and the cruise and HHDDT_S modes represent freeway operation. The test mode creation used the method of joining selected truck trips together while ensuring that they offered a reasonable statistical representation of the whole database by using a least-square errors method. Least-square errors between test modes and the database are less than 5%. The four test modes are presented in normalized engine

The crystal structure and phase stability of the zeta phase in the group VB transition metal carbides: a computational investigation.

The crystal structure and composition of the zeta phase in the group VB transition metal carbides are not completely understood despite decades of experimental studies. As such, the phase rarely appears on phase diagrams of the group VB transition metal carbides. There is currently renewed interest in this phase, as tantalum carbide composites exhibit high fracture toughness in the presence of this phase. This work extends the initial computational study using density functional theory of the phase stability of the zeta phase in the tantalum carbide system, where the tantalum carbide zeta-phase crystal structure and stability were determined, to the niobium and vanadium carbides. It is shown that the zeta phases in the three systems share the same crystal structure and it is an equilibrium phase at low temperatures. The carbon atom ordering in the three different phases is explored and it is demonstrated that the zeta phase in the tantalum carbides prefers to order carbon atoms differently than in the niobium and vanadium carbide zeta phases. Finally, the properties of this crystal are computed, including elastic constants, electronic densities of states and phonon dispersion curves, to illustrate that this crystal structure is similar to other transition metal carbides.