Growth and germination of proteolytic Clostridium botulinum in vegetable-based media

The growth of proteolytic Clostridium botulinum from spore inocula and changes in spore counts in mushroom, broccoli, and potato purées were monitored. Four strains of proteolytic C. botulinum types A and B were inoculated separately at approximately 10(4) spores per ml in nutrient broth and vegetable purées incubated at 15, 20, and 30 degrees C for up to 52 days. The times for the cell populations to increase 1,000-fold (T1,000) in the tested vegetables (1 to 5 days at 30 degrees C, 3 to 16 days at 20 degrees C, 7 to > 52 days at 15 degrees C) were similar to those for meat or fish. Only temperature significantly influenced growth rate. In contrast, the lag phase depended on the strains and media tested, in addition to temperature. Lag times and T1,000S for proteolytic C. botulinum were longer for potato and broccoli purées than for mushroom purée. These differences were not related to different pHs or redox potentials. The germination level, evaluated as the decrease in the spore count, was low. The addition of a germinant mixture (L-cysteine, L-alanine, and sodium lactate) to some strains inoculated in vegetable purées resulted in an increase in germination, suggesting a lack of germination-triggering agents in the vegetable purées.     

In vitro degradation of 10 mono‐ and sesquiterpenes of plant origin by caprine rumen micro‐organisms

The extent of disappearance of 10 mono‐ and sesquiterpenes in presence of mixed rumen micro‐organisms has been measured in 24‐h batch cultures. The molecules that were tested are frequently found in the plants consumed by ruminants in highland pastures (limonene, β‐myrcene, β‐ocimene, α‐pinene, sabinene, γ‐terpinene and thymol) or are potential markers of the diet (camphene, β‐caryophyllene and α‐copaene). All terpenes were tested at 2 µL mL^?1, except α‐copaene and thymol, which were tested at 0.9 µL mL^?1 and 2 mg mL^?1, respectively. Camphene and thymol were not degraded to a significant extent. The disappearance of part of β‐caryophyllene, (?)‐limonene and γ‐terpinene could not be attributed to the direct action of rumen micro‐organisms but rather than to an effect of the extracellular medium. In contrast, a third group of one sesquiterpene (α‐copaene) and four monoterpenes (myrcene, β‐ocimene, α‐pinene and sabinene) was extensively degraded by rumen micro‐organisms, at rates of 1.6, 4.5, 3.5, 4.8 and 5.4 µmol mL^?1 inoculum day^?1, respectively. The preliminary exposure of rumen micro‐organisms to a specific blend of essential oils compounds, containing mainly thymol, guajacol and limonene, increased the extent of disappearance of γ‐terpinene only. Copyright © 2007 Society of Chemical Industry     

HERSCHEL—PACS Bolometer Arrays for Submillimeter Ground-Based Telescopes

The Herschel Space Observatory will carry onboard a new kind of bolometric architecture for the PACS (Photodetector Array Camera and Spectrometer) submillimeter photometer. These new generation CCD-like multiplexed bolometer arrays are buttable and enable the conception of large fully sampled focal planes either for space or for ground-based telescopes. We present here some development for ground-based applications in the context of the ARTEMIS (ARchitecture de bolomètres pour des TElescopes sub-MIllimétriques au Sol) project. We have developed an electro-thermal numerical model that simulates the performances of these semiconducting bolometers under specific ground-based conditions (different wavelengths and background powers for example). This model permits to determine the optimal parameters for each condition and shows that the bolometers can be background limited in each atmospheric transmission window between 200 and 450 microns. We also describe the optical system that provides a high optical efficiency in each submillimeter atmospheric window. Astronomical observations made with a prototype on the APEX telescope are presented.     

Use of volatile compound metabolic signatures in poultry liver to back-trace dietary exposure to rapidly metabolized xenobiotics

The study investigated the feasibility of using volatile compound signatures of liver tissues in poultry to detect previous dietary exposure to different types of xenobiotic. Six groups of broiler chickens were fed a similar diet either noncontaminated or contaminated with polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs; 3.14 pg WHO-TEQ/g feed, 12% moisture), polychlorinated biphenyls (PCBs; 0.08 pg WHO-TEQ/g feed, 12% moisture), polybrominated diphenyl ethers (PBDEs; 1.63 ng/g feed, 12% moisture), polycyclic aromatic hydrocarbons (PAHs; 0.72 μg/g fresh matter), or coccidiostats (0.5 mg/g feed, fresh matter). Each chicken liver was analyzed by solid-phase microextraction - mass spectrometry (SPME-MS) for volatile compound metabolic signature and by gas chromatography - high resolution mass spectrometry (GC-HRMS), gas chromatography - tandem mass spectrometry (GC-MS/MS), and liquid chromatography - tandem mass spectrometry (LC-MS/MS) to quantify xenobiotic residues. Volatile compound signature evidenced a liver metabolic response to PAH although these rapidly metabolized xenobiotics are undetectable in this organ by the reference methods. Similarly, the volatile compound metabolic signature enabled to differentiate the noncontaminated chickens from those contaminated with PBDEs or coccidiostats. In contrast, no clear signature was pointed out for slowly metabolized compounds such as PCDD/Fs and PCBs although their residues were found in liver at 50.93 (±6.71) and 0.67 (±0.1) pg WHO-TEQ/g fat, respectively.     

A cathodoluminescence study of boron doped {111}-homoepitaxial diamond films

In this work we use cathodoluminescence (CL) at liquid helium temperature to investigate the boron incorporation in {111}-homoepitaxial diamond films, grown outside the visible plasma ball by the Microwave plasma-assisted chemical vapor deposition (MPCVD) technique. The boron concentration of this set of films covers the whole possible doping range divided into four parts: Low doping (5 × 10¹⁶ < [B] < 1.5 × 10¹⁹ cm^? 3), high doping (1.5 × 10¹⁹ < [B] < 3 × 10²⁰ cm^? 3), heavy doping (3 × 10²⁰ < [B] < 2 × 10²¹ cm^? 3), and phase separation range ([B] > 2 × 10²¹ cm^? 3). The phase separation occurs for very high boron concentrations, between the diamond phase (sp³ carbon) and the other components of the layer, namely sp² carbon and boron. A part of them is accumulated outside the diamond lattice.This detailed cathodoluminescence investigation of {111}-homoepitaxial diamond films has led to determining the doping range of the films and following the evolution of their crystalline quality when the boron concentration increases. In addition, a comparison between {111} and {100} films in the same doping ranges has been undertaken.     

Ajustement Mathématique de Paramètres Ionosphériques

Annals of Telecommunications - Les auteurs rappellent les aspects expérimentaux des résonances ionosphériques aux harmoniques de la gyrofréquence et montrent comment on peut les...     

Novel Engineered Ion Channel Provides Controllable Ion Permeability for Polyelectrolyte Microcapsules Coated with a Lipid Membrane

The development of nanostructured microcapsules based on a biomimetic lipid bilayer membrane (BLM) coating of poly(sodium styrenesulfonate) (PSS)/poly(allylamine hydrochloride) (PAH) polyelectrolyte hollow microcapsules is reported. A novel engineered ion channel, gramicidin (bis‐gA), incorporated into the lipid membrane coating provides a functional capability to control transport across the microcapsule wall. The microcapsules provide transport and permeation for drug‐analog neutral species, as well as positively and negatively charged ionic species. This controlled transport can be tuned for selective release biomimetically by controlling the gating of incorporated bis‐gA ion channels. This system provides a platform for the creation of “smart” biomimetic delivery vessels for the effective and selective therapeutic delivery and targeting of drugs.