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Runaway Reactions – Their Course and Methods for the Choice and Design of Safe Processes. Literature about runaway reactions is usually concerned with the consequences of explosions such as destruction and emission of hazardous and inflammable substances. DIERS literature describes methods for the design of relief orifices for which experimental studies are necessary. Only few data are available relating to the course of runaway reactions, which, more-over, are also attributable to variety of causes. The present report describes the various process deviations which can trigger a thermal explosion. In addition, the determination of the necessary data and considerations for risk analysis and for the development of inherently safe processes and for lessening the consequences of thermal explosions are discussed. Any possible dangerous process deviation is illustrated with the aid of examples and experimental data obtained in laboratory experiments. The various dangerous process states which can lead to a thermal explosion are thus subjected to systematic study.     

Influence of a Constant Magnetic Field on Nervous Tissues: II. Voltage-Clamp Studies

In this paper a study of the biomagnetic response of the lobster nerve membrane is reported. Experiments were made on the giant axon of the circumesophageal connective of the lobster in order to investigate the influence of a constant strong magnetic field upon the membrane potentials and the transmembrane currents under voltage-clamp conditions, using the double sucrose gap technique. It was found that within the uncertainties and limitations of these experiments, neither the membrane potentials nor the transmembrane currents were affected in any detectable manner by a constant 1.2 T magnetic field parallel or perpendicular to the axon.     

Interfacial Rheology Measured with a Spinning Drop Interfacial Rheometer: Particularities in More Realistic Surfactant–Oil–Water Systems Close to Optimum Formulation at HLDN = 0

Three different cases were selected to study the effect of physicochemical formulation on interfacial rheology properties of surfactant–oil–water (SOW) systems by increasing the complexity of the system from a basic case. This was performed by changing the normalized hydrophilic–lipophilic deviation (HLD_N) to attain the optimum formulation at HLD_N = 0. Two types of SOW systems were studied: the first one used an ionic surfactant with a salinity scan, and the second one a mixture of two nonionic surfactants in a formulation scan produced by changing their proportion. Both of them contained cyclohexane as a pure oil phase, without alcohol. Sec-butanol was then added as a co-surfactant with hardly any formulation influence on HLD_N. The complexity in interfacial rheology was then increased by changing the oil to a light crude with low asphaltene content. The interfacial rheology is also reported for a realistic system with a high asphaltene content comprised of crude oil diluted in cyclohexane with a conventional surfactant and a commercial demulsifier. The findings confirm that at optimum formulation and whatever the scanning variable (salinity, average ethylene oxide number in the nonionic surfactant mixture, or surfactant/demulsifier concentration), the interfacial tension, and interfacial elastic moduli E, E′, and E″ exhibit a deep minimum. These observations are related to the acceleration of the surfactant exchanges between the interface, oil, and water, near the optimum formulation. Several arguments are put forward to explain how these findings could contribute to the decrease in emulsion stability at HLD_N = 0.     

Influence of Two-Photon Absorption Anisotropy on Terahertz Emission Through Optical Rectification in Zinc-Blende Crystals

We report for the first time on the observation of an angular anisotropy of the THz signal generated by optical rectification in a < 111 > ZnTe crystal. This cubic (zinc-blende) crystal in the <?111 > orientation exhibits both transverse isotropy for optical effects involving the linear χ⁽¹⁾ and nonlinear χ⁽²⁾ susceptibilities. Thus, the observed anisotropy can only be related to χ⁽³⁾ effect, namely two-photon absorption, which leads to the photo-generation of free carriers that absorb the generated THz signal. Two-photon absorption in zinc-blende crystals is known to be due to a spin-orbit interaction between the valence and higher-conduction bands. We perform a couple of measurements that confirm our hypothesis, as well as we fit the recorded data with a simple model. This two-photon absorption effect makes difficult an efficient generation, through optical rectification in <?111 > zinc-blende crystals, of THz beams of any given polarization state by only monitoring the laser pump polarization.     

Estimating non-fatal road casualties in a large French county, using the capture-recapture method

INTRODUCTION: Non-fatal road casualties are under-reported, with official figures coming from the police. In the French Rh?ne county, a road trauma registry constitutes a second source of reporting but its completeness needs to be assessed. We also wish to estimate an incidence rate of non-fatal road casualties that is corrected for under-count. METHODS: Having two sources of reporting available, we can apply the capture-recapture method under certain conditions. To take into account different reporting probabilities among casualties, the capture-recapture analysis is stratified according to injury severity (New Injury Severity Score=NISS), road user type and human third party. To evaluate the sensitivity of the capture-recapture estimate on the number of matched casualties between the police file and the registry, three scenarios of record-linkage are considered. RESULTS: For serious (NISS 9+) non-fatal road casualties, the police ascertainment rate is at most 57%, the registry ascertainment rate is at most 87%, and the aggregate ascertainment rate is at most 95%. The ascertainment-corrected incidence rate for serious (NISS 9+) non-fatal road casualties is at least 65 per 100,000. CONCLUSION: The degree of completeness of the registry for serious casualties is rather high, though not satisfactory.     

High-finesse Fabry-Perot electro-optic sensors with enhanced sensitivity and high spatial resolution

We present a high-finesse optical cavity containing a LiTaO(3) electro-optic crystal, devoted to free-space electric field characterization. Theoretical considerations will show that the modulation depth is directly related to the transversal components of the field to be measured, thus opening the way to vectorial mapping of the electric field using a single electro-optic crystal. Also, a discussion about noise and sensitivity will be given. As the latter increases with the effective cavity length, and bandwidth decreases, a trade-off is realized, allowing us to measure an electric field of 60 mV/m/ sqrt[Hz] in a 110 MHz bandwidth. Cavity dimensions are less than 8 mm(3), giving an inner-crystal transverse spatial resolution of 70 microm and allowing pigtailed systems to integrate.     

Five-substrate cocktail as a sensor array for measuring enzyme activity fingerprints of lipases and esterases

Substrate arrays for measuring enzyme activity fingerprints can be conveniently formulated as cocktails designed such that the reaction products can be separated and quantified by analytical high-performance liquid chromatography (HPLC). Fingerprinting of lipases and esterases, an important class of microbial enzymes, is reported with a cocktail of only five substrates as a practical fingerprinting reagent. An unusually strong C4-esterase activity was thus revealed in a recently discovered microbial esterase.     

Analysis of Amyloid-β Peptides in Cerebrospinal Fluid Samples by Capillary Electrophoresis Coupled with LIF Detection

We report a CE-LIF method for the separation and detection of five synthetic amyloid-β peptides corresponding to an important family of CSF-biomarkers in the context of Alzheimer disease (AD). The presumed most relevant peptides (Aβ1-42, Aβ1-40, and Aβ1-38) that may support the differentiation between AD and healthy patients or other dementias were successfully detected in CSF by incorporating an immunoconcentration step prior to CE analysis of derivatized peptides. We labeled the Aβ peptides with a fluoroprobe dye before CE-LIF analysis. This reagent reacts with the amino groups of lysine residues and produced mostly ditagged Aβ peptides under the proposed experimental conditions. The labeling reaction displayed similar efficiency with each one of the five different synthetic Aβ peptides that were tested. The limit of detection of the CE-LIF method approached 280 attomoles of injected synthetic labeled Aβ peptides. We obtained excellent correlation between peak areas and peptide concentrations from 35 nM to 750 nM. For the detection of Aβ peptides in human CSF samples, we enriched the peptides by immunoprecipitation prior to the CE-LIF analysis. The comparison of the CE-LIF profiles obtained from CSF samples from 3 AD patients and 4 non-demented control subjects indicated noticeable differences, suggesting that this method, which relies on a multibiomarker approach, may have potential as a clinical diagnostic test for AD.     

Influence of manufacturing conditions on the conjugated linoleic acid content and the isomer composition in ripened French Emmental cheese

In a study of the evolution of conjugated linoleic acid (CLA) during cheese production, the influence of Emmental cheese processing on the CLA content and the CLA isomer composition was evaluated. The use of raw and thermised milk, changes of processing temperature and the effect of propionic acid bacteria (PAB) were investigated. The content of CLA in raw milk was 8.6 +/- 1.9 mg/g fat and in the ripened cheese at 70 d was 8.6 +/- 1.6 mg/g fat, under normal processing conditions. No changes in the CLA content and CLA isomer composition were observed during Emmental cheese manufacturing process. Changes in cooking and moulding temperatures did not influence the CLA content. CLA content of cheese made from microfiltered milk with two different Propionibacterium freudenreichii strains was very close to cheeses made without PAB. CLA levels seem to be stable in this type of dairy product under the conditions examined.     

Dielectric behavior of beef meat in the 1-1500kHz range: Simulation with the Fricke/Cole-Cole model

The electrical properties of biological tissues have been researched for many years. Impedance measurements observed with increasing frequencies are mainly attributed to changes in membrane conductivity and ion and charged-molecule mobility (mainly Na⁺, K⁺, CL⁻ ions). Equivalent circuits with passive electrical components are frequently used as a support model for presentation and analyses of the behavior of tissues submitted to electrical fields. Fricke proposed an electrical model where the elements are resistive and capacitive. The model is composed of a resistive element (Rp) representing extracellular fluids (ECF) placed in parallel with a capacitive element (Cs) representing insulating membranes in series and a resistive element (Rs) representing intracellular fluids (ICF). This model is able to describe impedance measurements: at lower frequencies, most of the current flows around the cells without being able to penetrate them, while at higher frequencies the membranes lose their insulating properties and the current flows through both the extracellular and intracellular compartments. Since meat ageing induces structural change, particularly in membrane integrity, the insulating properties of membranes decrease, and intracellular and extracellular electrolytes mix, thus driving changes in their electrical properties. We report a method combining the Fricke and Cole–Cole models that was developed to monitor and explain tissues conductivity changes in preferential directions during beef meat ageing.