Emergency and Resuscitation Emergency Mobile Service--Neuchatel experience

RATIONALE AND OBJECTIVES: We investigated the possible cardiac effects of oxygen addition to contrast media (CM) during coronary arteriography in dogs that did and did not have ischemic heart failure. METHODS: Acute ischemic heart failure was induced by injecting small plastic microspheres into the left coronary artery of 18 dogs. Hemodynamic and electrophysiologic measurements were performed during a single injection before and during heart failure and during a single injection and five rapidly repeated CM injections during heart failure. Iohexol supplemented with electrolytes (iohexol + electrolytes = IPE), oxygenated IPE (IPE+O), Ringer acetate, and oxygenated Ringer acetate were injected into the left coronary artery. RESULTS: Single injections of IPE and IPE+O induced small hemodynamic and electrophysiologic effects. However, repeated injections of IPE and IPE+O increased left ventricular inotropy (maximum value of the first derivative of the left ventricular pressure) by 36% and 39%, reduced heart rate by 7% (for both), and lengthened QTc time (corrected QT interval) by 39 and 38 msec, respectively. A comparison of IPE and IPE+O revealed no statistically significant differences. CONCLUSION: Although electrolyte addition to nonionic CM may reduce the risk of cardiac complications during coronary arteriography, oxygenation does not seem to significantly further reduce this risk.     

Generation of discrete first‐ and second‐order sensitivities for single shooting

In this work, an approach to the forward generation of discrete first‐ and second‐order sensitivities is proposed. For this purpose, an algorithm has been developed, which can basically be applied to general implicit differential‐algebraic equation (DAE) systems. Moreover, the approach has been tailored to both the generation of directional derivatives and sensitivities with respect to discontinuous control trajectories. The implementation of the method is discussed here for the orthogonal collocation method based on Legendre–Gauss–Radau points and considering the linear implicit DAE type, which arises in problems related to chemical engineering. Lastly, the approach has been applied to three case studies of different complexities. The corresponding performance for the generation of Jacobian and Hessian information is discussed in detail. © 2012 American Institute of Chemical Engineers AIChE J, 58: 3110–3122, 2012     

Phase formation and microstructure during laser sintering and crystallization of a 4.2 MgO·5.0 ZnO·44.1 CaO·26.7 Al<Subscript>2</Subscript>O<Subscript>3</Subscript>·20.0 SiO<Subscript>2</Subscript> glass

In order to produce housings for high-temperature applications, alumina is a highly advantageous material because it has a high chemical durability and withstands high temperatures. If alumina is to be sealed, materials are necessary which have an adapted coefficient of thermal expansion (8.6 × 10^?6 K^?1). If temperature-sensitive components have to be encapsulated, a rapid laser sealing process is highly advantageous. This process requires a glass which can rapidly be crystallized. In this paper, a glass powder with the composition 4.2 MgO·5.0 ZnO·44.1·CaO·26.7 Al₂O₃·20.0 SiO₂ was sintered and subsequently crystallized using a CO₂-laser. As crystalline phases, predominantly a solid solution of akermanite and gehlenite (AGSS) was formed and as phases with minor concentrations Al₂O₃, spinel/gahnite solid solution and ZnO. The AGSS grains have sizes of approximately 5 µm, and Mg and Zn are enriched at the grain boundaries. After sealing at temperatures of 985 and 1135 °C, a similar microstructure and similar grain sizes were observed. The AGSS seems to nucleate at the glass/Al₂O₃ interface but also in the bulk. The AGSS and all other phases do not show a preferred orientation. The resulting coefficients of thermal expansion fit well to that of Al₂O₃.     

Methods for determining regularization for atmospheric retrieval problems

The atmosphere of Earth has already been investigated by several spaceborne instruments, and several further instruments will be launched, e.g., NASA's Earth Observing System Aura platform and the European Space Agency's Environmental Satellite. To stabilize the results in atmospheric retrievals, constraints are used in the iteration process. Therefore hard constraints (discretization of the retrieval grid) and soft constraints (regularization operators) are included in the retrieval. Tikhonov regularization is often used as a soft constraint. In this study, different types of Tikhonov operator were compared, and several new methods were developed to determine the optimal strength of the constraint operationally. The resulting regularization parameters were applied successfully to an ozone retrieval from simulated nadir sounding spectra like those expected to be measured by the Tropospheric Emission Spectrometer, which is part of the Aura platform. Retrievals were characterized by means of estimated error, averaging kernel, vertical resolution, and degrees of freedom.     

Biomass-integrated gasification fuel cell systems – Part 1: Definition of systems and technical analysis

The combination of biomass gasification with fuel cells is commonly referred to as Biomass-Integrated gasification fuel cell systems (B-IGFC). In this two-part system analysis, we investigate seven B-IGFC systems and four solid oxide fuel cell (SOFC) designs with a system power output of around 1 MW_el. In this part, we define the B-IGFC systems and asses their technical feasibility using a finite volume based SOFC model and ASPEN PLUS™ models for the simulation of the gas processing.     

Automated determination of the center of rotation in tomography data

Tomographic reconstruction requires precise knowledge of the position of the center of rotation in the sinogram data; otherwise, artifacts are introduced into the reconstruction. In parallel-beam microtomography, where resolution in the 1 microm range is reached, the center of rotation is often only known with insufficient accuracy. We present three image metrics for the scoring of tomographic reconstructions and an iterative procedure for the determination of the position of the optimum center of rotation. The metrics are applied to model systems as well as to microtomography data from a synchrotron radiation source. The center of rotation is determined using the image metrics and compared with the results obtained by the center-of-mass method and by image registration. It is found that the image metrics make it possible to determine the axis position reliably at well below the resolution of one detector bin in an automated procedure.     

An SMO algorithm for the potential support vector machine

We describe a fast sequential minimal optimization (SMO) procedure for solving the dual optimization problem of the recently proposed potential support vector machine (P-SVM). The new SMO consists of a sequence of iteration steps in which the Lagrangian is optimized with respect to either one (single SMO) or two (dual SMO) of the Lagrange multipliers while keeping the other variables fixed. An efficient selection procedure for Lagrange multipliers is given, and two heuristics for improving the SMO procedure are described: block optimization and annealing of the regularization parameter epsilon. A comparison of the variants shows that the dual SMO, including block optimization and annealing, performs efficiently in terms of computation time. In contrast to standard support vector machines (SVMs), the P-SVM is applicable to arbitrary dyadic data sets, but benchmarks are provided against libSVM's epsilon-SVR and C-SVC implementations for problems that are also solvable by standard SVM methods. For those problems, computation time of the P-SVM is comparable to or somewhat higher than the standard SVM. The number of support vectors found by the P-SVM is usually much smaller for the same generalization performance.     

Scanning electron microscopical studies of developing gustatory papillae in humans

Yeast biomass (Saccharomyces sp.) produced in local breweries as a by-product was utilized in this study. Percent proximate composition, amino acid composition, and protein nutritive value were determined for the yeast cell biomass (YC), a sodium perchlorate extracted and isoelectrically precipitated protein concentrate (P-PC), and a sodium trimetaphosphate treated extract followed by isoelectrical precipitation (TMP-PC). Protein concentrates averaged 75% protein as compared to 48.5% in the yeast biomass. Precipitation of the protein in the presence of either sodium perchlorate or sodium trimetaphosphate was reduced to 71% and 51% of the cell RNA content, respectively. Protein nutritive value was 70% of casein when measured by the protein efficiency ratio (PER), and over 90% of casein when net protein utilization (NPUa) was the criteria of evaluation.