Sine-Gordon theory for the equation of state of classical hard-core Coulomb systems. II. High-temperature expansion

We perform a high-temperature expansion of the grand potential of the restrictive primitive model of electrolytes in the frame of the extended sine-Gordon theory exposed in the companion paper. We recover a result already obtained by Stell an Lebowitz (J. Chem. Phys., 49, 3706 (1968)) by means of diagrammatic expansions

Degradation of cassava linamarin by lactic acid bacteria

Six out of ten lactic acid bacteria strains tested displayed linamarase activity. #Lactobacillus plantarum$ strain A6 displayed the greatest activity affecting 36 U/g cells on MRS cellobiose. The strain also broke down in less than 2 hours the linamarin extracted from cassava juice. HPLC analysis of the products of the reaction showed that the bacteria converted the linamarin into lactic acid and acetone cyanohydrin. (Résumé d'auteur

Purification and characterization of an extracellular amylase from Lactobacillus plantarum strain A6

Extracellular amylase from #Lactobacillus plantarum$ A6 was purified by fractionated precipitation with ammonium sulphate and by anion exchange chromatography. The homogeneity of the purified fraction was tested by polyacrylamide gel electrophoresis and showed multiple amylase forms. A major form had an estimated molecular weight of 50 kDa. It was identified as an alpha-amylase, with an optimum pH of 5.5, an optimum temperature of 65°C and Km value of 2.38 g l-1 with soluble starch substrate. The enzyme was inhibited by N-bromosuccinimide, iodine and acetic acid. The enzyme activation energy was 30.9 kJ mol-1. (Résumé d'auteur

Nitrous oxide distribution and its origin in the central and eastern South Pacific Subtropical Gyre

The mechanisms of microbial nitrous oxide (N<sub>2</sub>O) production in the ocean have been the subject of many discussions in recent years. New isotopomeric tools can further refine our knowledge of N<sub>2</sub>O sources in natural environments. This study compares hydrographic, N<sub>2</sub>O concentration, and N<sub>2</sub>O isotopic and isotopomeric data from three stations along a coast-perpendicular transect in the South Pacific Ocean, extending from the center (Sts. GYR and EGY) of the subtropical oligotrophic gyre (~26° S; 114° W) to the upwelling zone (St. UPX) off the central Chilean coast (~34° S). Although AOU/N<sub>2</sub>O and NO<sub>3</sub><sup>−</sup> trends support the idea that most of the N<sub>2</sub>O (mainly from intermediate water (200–600 m)) comes from nitrification, N<sub>2</sub>O isotopomeric composition (intramolecular distribution of <sup>15</sup>N isotopes) expressed as SP (site preference of <sup>15</sup>N) shows low values (10 to 12permil) that could be attributed to the production through of microbial nitrifier denitrification (reduction of nitrite to N<sub>2</sub>O mediated by ammonium oxidizers). The coincidence of this SP signal with high – stability layer, where sinking organic particles can accumulate, suggests that N<sub>2</sub>O could be produced by nitrifier denitrification inside particles. It is postulated that deceleration of particles in the pycnocline can modify the advection - diffusion balance inside particles, allowing the accumulation of nitrite and O<sub>2</sub> depletion suitable for nitrifier denitrication. As lateral advection seems to be relatively insignificant in the gyre, in situ nitrifier denitrification could account for 40–50% of the N<sub>2</sub>O produced in this layer. In contrast, coastal upwelling system is characterized by O<sub>2</sub> deficient condition and some N deficit in a eutrophic system. Here, N<sub>2</sub>O accumulates up to 480% saturation, and isotopic and isotopomer signals show highly complex N<sub>2</sub>O production processes, which presumably reflect both the effect of nitrification and denitrification at low O<sub>2</sub> levels on N<sub>2</sub>O production, but net N<sub>2</sub>O consumption by denitrification was not observed

Periodic formation and propagation of double layers in the expanding chamber of an inductive discharge operating in Ar/SF₆ mixtures

It has previously been shown [Tuszewski et al., Plasma Sources Sci. Technol.12, 396 (2003)] that inductive discharges in electronegative gases are subject to two types of instability: the sourceinstability related to the E to H transition and a transport instability, occurring downstream when an expanding chamber is present. These two types of instability are observed in our “helicon” reactor operated without a static magnetic field in low-pressure Ar∕SF6 mixtures. Temporally and spatially resolved measurements show that, in our experiment, the downstream instability is a periodic formation and propagation of a double layer. The double layer is born at the end of the source tube and propagates slowly to the end of the expansion region with a velocity of 150ms⁻¹

Equilibrium model for two low-pressure electronegative plasmas connected by a double layer

Plihon et al. [J. Appl. Phys.98, 023306 (2005)] have recently shown that double layers usually form during the expansion of a low pressure electronegative plasma. These double layers act as permeable internal boundaries between the source (upstream) plasma and the downstream expanding plasma; positive ions flow from upstream to downstream whereas negative ions flow in the opposite direction. So far, the detailed physical mechanisms leading to their formation have not been identified. In this paper, we develop a model for the two plasma equilibria, upstream and downstream, assuming that the double layer exists and couples the two plasmas. At very low pressure, typically 0.5mTorr, the coupling is strong and acts both ways. The negative ions created downstream contributes to the upstream equilibrium as well as the upstream positive ions contribute to the downstream equilibrium. As the pressure increases, the situation becomes asymmetric. The sourceplasma is not affected by the negative ions flowing from downstream, whereas the positive ions coming from the source control the downstream plasma equilibrium, where local ionization is negligible.This work has been supported by the European Space Agency, under Ariadna Study Contract No. ACT-04-3101. One of the authors A.J.L. acknowledges the hospitality of the LPTP, where the collaboration was begun

Ecology and biogeochemistry of contrasting trophic environments in the South East Pacific by carbon isotope ratios on lipid biomarkers

International audienceThe distribution of lipid biomarkers and their carbon isotope composition was investigated on suspended particles from different contrasting trophic environments at six sites in the South East Pacific. High algal biomass with diatom-related lipids was characteristic in the upwelling zone, whereas haptophyte lipids were proportionally most abundant in the nutrient-poor settings of the centre of the South Pacific Gyre and on its easter edge. Dinoflagellate–sterols were minor contributors in all of the studied area and cyanobacteria-hydrocarbons were at maximum in the high nutrient low chlorophyll regime of the subequatorial waters at near the Marquesas archipelago. The taxonomic and spatial variability of the relationships between carbon photosynthetic fractionation and environmental conditions for four specific algal taxa (diatoms, haptophytes, dinoflagellates and cyanobacteria) was also investigated. The carbon isotope fractionation factor (ep) of the diatom marker varied over a range of 16‰ along the different trophic systems. In contrast, ep of dinoflagellate, cyanobacteria and alkenone markers varied only by 7–10‰. The low fractionation factors and small variations between the different phytoplankton markers measured in the upwelling area likely reveals uniformly high specific growth rates within the four phytoplankton taxa, and/or that transport of inorganic carbon into phytoplankton cells may not only occur by diffusion but by other carbon concentrating mechanisms (CCM). In contrast, in the oligotrophic zone, i.e. gyre and eastgyre, relatively high ep values, especially for the diatom marker, indicate diffusive CO2 uptake by the eukaryotic phytoplankton. At these nutrient-poor sites, the lowest ep values for haptophytes, dinoflagellates and cyanobacteria infer higher growth rates compared to diatoms

Drug related problems and pharmacist interventions in a geriatric unit employing electronic prescribing

Background Computerised physician order entry (CPOE) and the integration of a pharmacist in clinical wards have been shown to prevent drug related problems (DRPs). Objectives The primary objective was to make an inventory of the DRPs and resident pharmacist on-ward interventions (PIs) identified in a geriatric acute care unit using CPOE system. The secondary objective was to evaluate the physicians\u27 acceptance of the proposed interventions. Setting A 26-bed geriatric ward of a 1,300-bed teaching hospital. Method A 6-month descriptive study with prescription analysis and recommendations to physicians by a resident pharmacist during five half days a week. Main outcome measures Patients\u27 characteristics, number of prescribed drugs per patient, nature and frequency of DRPs and PIs, physicians\u27 acceptance and drugs questioned. Results Resident pharmacist reviewed 311 patients and identified 241 DRPs. One hundred and fifty-two patients (49 %) had at least one DRP (mean +/- A SD age 87 +/- A 6 years, mean +/- A SD number of prescribed drugs 10.7 +/- A 3.4). Most frequent DRPs were: untreated indication (n = 58, 24.1 %), dose too high (n = 46, 19.1 %), improper administration (n = 31, 12.9 %) and drug interactions (n = 23, 9.5 %). The rate of physicians\u27 acceptance was 90.0 % (7.5 % refusals, 2.5 % not assessable). DRPs related to CPOE system misuse (n = 35, 14.5 %) appeared as a worrying phenomenon (e.g., errors in selecting dosage or unit, or duplication of therapy). Conclusion A resident pharmacist detected various DRPs. Most PIs were accepted. DRPs related to the misuse of the CPOE system appeared potentially dangerous and need particular attention by healthcare professionals. The description of the DRPs is an essential step for implementation of targeted clinical pharmacy services in order to optimize pharmacists\u27 job time