Lethal effect of electric fields on isolated ventricular myocytes

Defibrillator-type shocks may cause electric and contractile dysfunction. In this study, we determined the relationship between probability of lethal injury and electric field intensity ($E$ ) in isolated rat ventricular myocytes, with emphasis on field orientation and stimulus waveform. This relationship was sigmoidal with irreversible injury for $E ≫ hbox{50 V/cm}$ . During both threshold and lethal stimulation, cells were twofold more sensitive to the field when it was applied longitudinally (versus transversally) to the cell major axis. For a given $E$, the estimated maximum variation of transmembrane potential ( $Delta V_{max }$) was greater for longitudinal stimuli, which might account for the greater sensitivity to the field. Cell death, however, occurred at lower maximum $Delta V_{max }$ values for transversal shocks. This might be explained by a less steep spatial decay of transmembrane potential predicted for transversal stimulation, which would possibly result in occurrence of electroporation in a larger membrane area. For the same stimulus duration, cells were less sensitive to field-induced injury when shocks were biphasic (versus monophasic). Ours results indicate that, although significant myocyte death may occur in the $E$ range expected during clinical defibrillation, biphasic shocks are less likely to produce irreversible cell injury.      

Temperature-dependent characteristics and single-mode performanceof AlGaInP-based 670-690-nm vertical-cavity surface-emitting lasers

We report on temperature dependent characteristics and single mode performance of one-wave cavity, planar implanted, AlGaInP-based vertical-cavity surface emitting lasers. By optimizing the overlap between the gain peak and the cavity mode of the structure, we demonstrate record device performance, including 8.2 mW maximum output power and 11% power conversion efficiency for multimode operation and 1.9 mW and 9.6% power conversion efficiency for single mode operation at 687 nm. Improved performance at elevated temperatures is also achieved, with 1.5 mW output power demonstrated at 50°C from a 15-μm-diameter device     

Transformation champ proche — champ lointain bidimensionnelle et monodimensionnelle appliquée à des mesures de SER

In high frequency thercs measurement of large target must be done at important distances, so the distance of measurement (Fraunhofer’s distance) R is given by R ≥ 2d² /λ where d is the tranversal length of the target and λ the radiation wavelength. In this paper we present a method for target that are large relative to the curvature of the spherical wavefront and the curvature of the cylindrical wavefront. A two-dimensional analytical algorithm transforms the spherical wave (near-field) measurement into the desired plane wave (far-field) and a one-dimensionnal analytical algorithm transforms the cylindrical wave (near-field) measurement into the desired plane wave (far-field). We present some results on simulations and measurements. A comparison of one-dimensional and two-dimensional methods demonstrates the efficiency of the two dimensional methods.     

Effects of electrical and mechanical stunning methods on meat quality in ostriches

The effect of electrical and captive needle air pressure stunning methods on some meat quality parameters was examined in ostriches under practical conditions. One hundred and fifteen ostriches were used in three experiments. The ostriches were stunned either electrically (head only) or by using a captive needle with air pressure. In the first experiment the ostriches were stunned at 90 V (～effectively 52 V), 200 V and by captive needle using air pressure. In the second experiment voltages of 175 and 200 V were applied and a captive needle stunning method using air pressure. In the third experiment the birds were stunned at 175 V with a short stun/stick interval. Experiments 2 and 3 were performed in a different slaughterhouse from experiment 1. Meat quality was assessed by measuring the pH, temperature and colour at 45 min and 18 h post mortem and by determining water binding capacity and haemorrhage score at 18 h post mortem in the big drum, tender loin and triangular filet muscles. The measured stunning parameters in the first experiment were 204±96 mA (～52 V) during 11±1 s and 556±85 mA (～200 V) during 6±0 s. The stun/stick interval was 136±38 s. The rigor mortis value in the tender loin and both pH(1) and pH(2) in the big drum, tender loin and triangular filet muscles were (p<0.05) lower when stunned with air pressure compared with electrical stunning. Moreover internal light scattering remained higher. The measured currents in the second experiment were 561±226 mA (～173 V) during 6±2 s and 518±120 mA (～200 V) during 6 s. The stun/stick interval was 39±12 s. The pH at 45 min and 18 h differed (p<0.05) in the tender loin and triangular filet muscles as did the temperature at 45 min in the three muscles between the different stunning groups. The stunning in the third experiment was carried out with 548±180 mA during 6±2 s. The stun/stick interval was 5±2 s. After the short stun/stick interval the pH(2) was lower (p<0.05) for the tender loin and triangular filet muscles and the wetness of the filter paper of the big drum was (p<0.05) lower compared with the other groups. Our experiments showed that stunning methods affected several meat quality parameters. Using a high electrical stunning current, captive needle stunning or a short stun/stick interval may positively affect some parameters. More research is necessary to examine effects of pre slaughter handling on meat quality.     

Sur l’utilisation des équations intégrales en régime transitoire dans les problèmes d’électromagnétisme

It is possible in many cases by using space-time integral equations to compute the scattering and penetration of electromagnetic fields via explicit time-stepping diagrams. The case of conducting surfaces, thin scatterers, apertures and shieldings of finite conductivity are discussed with emphasis on the simplicity and the validity domain of the relevant equations. Examples concern the field of a far-located dipole incident on a cylinder with infinite conductivity, with an aperture or with resistive walls.     

Improved safety and efficacy in adaptive control of arterial bloodpressure through the use of a supervisor

A dual approach to adaptive control of arterial blood pressure using sodium nitroprusside is presented. In the clinical environment, a controller must be aggressive to achieve specific step response characteristics (less than 10 min setting time, less than 10 mm Hg overshoot), yet conservative enough to prevent overreactions to large disturbances, which are common in both the operating room and the intensive care unit. These mutually exclusive requirements make it difficult to design a closed-loop controller for this environment. To prevent possible overreactions while maintaining proper step response, an aggressive adaptive controller has been designed to achieve the desired step response, and a supervisor has been designed around the adaptive controller to limit potential overreactions in the presence of disturbances. Simulations and dog experiments demonstrate the potential for increased safety and efficacy using this dual approach to the control of a complex physiological system     

Flat-field spectrograph in SiO2/Si

The operation of a flat-field spectrograph in silica glass on silicon (SiO₂/Si) as a demultiplexer with 4-nm channel spacing in the 1.5-μm waveguide length region is demonstrated. The concept allows fabrication tolerances to be compensated simultaneously with the adjustment of fan-out. Fiber-to-fiber insertion loss of 10.1 dB and crosstalk attenuation >15 dB have been achieved     

Modelling the effect of uneven PWB surface on stencil bending during stencil printing process

In the mass assembly of today’s electronic circuits, solder paste is first printed onto the surface of the assembly boards through a metal mask called a stencil. The possible surface differences in level on the PWB, e.g. marking stickers or other protruding objects keep the stencil away from the PWB during stencil printing, can cause excessive printed volume of the solder paste, and solder bridges or other soldering failures can occur after reflow soldering. If these differences in level are not too high or they are sufficiently far from the soldering pads in lateral direction, the stencil can bend down to the pad during stencil printing and the volume of the deposited solder paste will be as expected.In our research a Finite Element Model (FEM) was created to investigate the stencil deformation and to determine the necessary distance between the pads and the local differences in level to achieve complete stencil contact to the PWB. A simple deformation measuring set-up was designed and fitted together to experimentally determine the mechanical parameters of the stencil and the squeegee, which were necessary for the FEM. PWB surface differences in level in the range of 0–90 μm and stencil foil thicknesses varying between 75 and 175 μm were inserted into the FEM as geometrical parameters and simulations were executed to calculate the minimum distances which are necessary to achieve perfect stencil contact to the PWB. The FEM was verified by comparing simulation results to experimental results obtained by real stencil printing.     

Modeling, simulation, and model-based control of the walkingmachine ALDURO

The system under investigation is the hydraulically driven autonomous large scale-combined legged and wheeled vehicle, the anthropomorphically legged and wheeled Duisburg robot (ALDURO). In this paper, a complete mechatronic simulation model, realized in the object-oriented programming language C++, is presented. It contains the mechanical system including an explicit solution of the kinematic loops, a model of the ground contact, and the dynamics of the complete hydraulic system, as well as a force-based motion control concept based on an exact input-output linearization using decentralized force controllers. Some simulation results are shown to demonstrate the function of the simulation model and the control concept presented     

UNICORE 6 — Recent and Future Advancements

UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments.