Towards eco-friendly biocides: preparation, antibiofilm activity of hemibastadin analogues.

The antibiofilm activity of three hemibastadins analogues was evaluated against different marine bacterial strains through mono-species biofilms and through a multi-species model of biofilm. Results showed that compound 3 exhibited interesting antibiofilm efficiencies effective concentrations (EC50 ) in the range of 30-100 µmol l-1 without acute toxicity against bacteria. Toxicity against nontargeted organisms was also considered showing that the compound did not affect the global bacterial community at a concentration of 75-100 µmol l-1 . These results provided baseline data concerning the toxicity of antibiofilm biocides against marine organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reports relevant information about antibiofilm activity of original derivatives of hemibastadin alkaloids. The most active compound was shown to act as a specific anti-biofilm inhibitor without affecting viability of the targeted bacteria no more than those of the global bacterial community of a seawater sample. Taken together, these findings indicate the potentiality of such compounds to be used as original nonbiocidal molecules for designing eco-friendly antifouling solutions.

Sensing of water dissolved in solvents using a 5.629 microm multimode quantum cascade laser.

We report herein the detection of liquid water dissolved in a variety of solvents using a thermoelectrically cooled, pulsed, Fabry-Perot quantum cascade laser, operating at 5.629 microm at room temperature. The prototype sensor system consisted of the laser, a series of off-axis parabolic mirrors, and two mercury cadmium telluride detectors. When applied to the detection of water in tetrahydrofurane, a limit of detection of 0.85 parts per million was achieved. It is envisaged that such a sensor would be well suited to process control applications within the pharmaceuticals industry.

Single-Frequency operation of External-Cavity VCSELs: Non-linear multimode temporal dynamics and quantum limit.

We present an experimental and theoretical investigation of the non-linear multimode dynamics of external-cavity VCSELs emitting at 1 and 2.3mm. We account for the stable single-frequency and linearly polarized emission by these laser sources, even in the presence of quantum noise and non-linear mode interactions originating from Four-Wave-Mixing via population pulsations in the quantum-wells. This fact is a consequence of the mode antiphase dynamics. Thanks to the high-Q external cavity configuration, the laser dynamics fall into the oscillation-relaxation-free class-A regime. The characteristic time to achieve single mode emission is ~ 1ms for a 15mm long cavity with an antireflection coated structure and no spectral filter, as for an "ideal" homogeneous gain laser. The side mode suppression ratio is as high as 40 dB, close to the quantum limit. The laser linewidth is at the quantum limit, and is ~ 1Hz at 1mW output. An experimental value <20 kHz has been established. Under standard conditions, without spectral filtering, the optimum cavity length for highly coherent single mode operation is expected in the range 5 to 30mm. Finally, for cavity lengths typically shorter than 5mm, we rather have an "ideal" homogeneous gain class-B laser, exhibiting oscillation-relaxation of the intensity in the 0.1GHz range. These properties contrast with the intrinsic strongly non-linear dynamics of conventional semiconductor lasers.

Looking into the volcano with a Mid-IR DFB diode laser and Cavity Enhanced Absorption Spectroscopy.

We report on the first application of extended-wavelength DFB diode lasers to Cavity-Enhanced Absorption Spectroscopy in-situ trace measurements on geothermal gases. The emission from the most active fumarole at the Solfatara volcano near Naples (Italy) was probed for the presence of CO and CH(4). After passing through a gas dryer and cooler, the volcanic gas flow (98% CO(2)) was analysed in real time for the concentration of these species, whose relatively strong absorption lines could be monitored simultaneously by a single Distributed Feed-Back (DFB) GaSb-based diode laser emitting around 2.33 mum (4300 cm(-1)) at room temperature. The concentrations were found to be about 3 ppm and 75 ppm, respectively, while actual detection limits for these molecules are around 1 ppb. We discuss the possibility of detecting other species of interest for volcanic emission monitoring.

[Value of electromyography in the child. Apropos of 1,624 examinations performed over a 3 year period]. / Intérêt de l'électromyographie chez l'enfant. A propos de 1624 examens réalisés en 3 ans.

EMG and nerve conduction studies have limitations and require particular consideration in children. The indications and the main results are considered from the study of 1624 EMGs in 1385 children under 15 years old seen over a period of 3 years. Classification of cases was based on clinical criteria. The diagnostic yield of EMG is emphasized in the evaluation of 122 children with hypotonia and weakness (all under 3 years old); abnormalities were demonstrated in 48% leading to the diagnosis of spinal muscular atrophy in 16%, of congenital myopathies in 11%, and of peripheral neuropathies in 8%. In 103 children with hypotonia associated with mental deficiency and/or seizures, evidence of a peripheral neuropathy was shown in 20%. EMG abnormalities allowing the diagnosis of hereditary motor and sensory neuropathies or myopathies were demonstrated in a wide range of clinical conditions. EMG appears to be useful for the early detection of hereditary myopathies or neuropathies in asymptomatic children. It may have also a prognostic value as in adults, especially in nerve traumas.

[Value of electromyography in the thoracic outlet syndrome (author's transl)]. / Le syndrome de la traversée thoraco-brachiale. Intérëts et limites de l'électromyographie.

Electromyogram studies were conducted in 55 patients with the thoracic outlet syndrome, together with the motor nerve conduction velocity (M.N.C.V) in the median cubital nerves, between the Erb's point and axilla and in the upper limb. Distal S.N.C.V. was measured in 19 cases. Proximal nerve compression was confirmed in 29% of cases, with associated carpal canal compression in 22%. The proximal N.C.V. of the median and cubital in the neurological forms, and of the median in the neurovascular forms, were significantly different from normal values in 18 control subjects, but were not so in the vascular forms. Through E.M.G. examination cannot confirm the need for surgery it can supply supportive evidence. No correlation between the clinical course and the proximal N.C.V. was found in the 18 patients seen after treatment (surgery in 13 cases).