Note: Efficient diode laser line narrowing using dual, feed-forward + feed-back laser frequency control.

We have achieved distributed feedback laser diode line narrowing by simultaneously acting on the diode current via a feed-back loop and on an external electrooptic phase modulator in feed-forward actuator. This configuration turns out to be very efficient in reaching large bandwidth in the phase correction: up to 15 MHz with commercial laser control units. About 98% of the laser power undergoes narrowing. The full width at half maximum of the narrowed optical spectrum is of less than 4 kHz. This configuration appears to be very convenient as the delay in the feed-forward control electronics is easily compensated for by a 20 m optical fiber roll.

In-vacuum Faraday isolation remote tuning.

In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air.

In-vacuum optical isolation changes by heating in a Faraday isolator.

We describe a model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal. The changes are particularly significant in the crystal thermal lensing (refraction index and thermal expansion) and in its Verdet constant and can be ascribed to the less efficient convection cooling of the magneto-optic crystal of the Faraday isolator. An isolation decrease by a factor of 10 is experimentally observed in a Faraday isolator that is used in a gravitational wave experiment (Virgo) with a 10 W input laser when going from air to vacuum. A finite element model simulation reproduces with a great accuracy the experimental data measured on Virgo and on a test bench. A first set of measurements of the thermal lensing has been used to characterize the losses of the crystal, which depend on the sample. The isolation factor measured on Virgo confirms the simulation model and the absorption losses of 0.0016 +/- 0.0002/cm for the TGG magneto-optic crystal used in the Faraday isolator.

Demographic evaluation of the fertility of aluminium industry workers: influence of exposure to heat and static magnetic fields.

A demographic analysis of the fertility of French aluminium industry workers was performed in order to evaluate the potential effects on male fertility of occupational exposure to heat and static magnetic fields occurring in certain workshops. Two groups of aluminium workers were studied: one group of 692 potroom workers exposed to heat and to static magnetic fields, and a control group of 588 workers from the same plants, who had not been exposed to these factors. The birthrate was significantly higher in the 'exposed' group than in the 'control' group. The relative birthrate ratio ('exposed' versus 'control') was 1.1 (P < 0.001). These results do not show any decrease in the fertility of potroom workers exposed to heat and static magnetic fields, when compared to other workers in the aluminium producing industry.

Limits of the mandibular symphysis as a donor site for bone grafts in early secondary cleft palate osteoplasty.

With the assistance of computed tomography, the bone volume in the symphysis was assessed on 28 historic mandibles with mixed dentition, before the eruption of the canines. The quantification gave an average bone volume of 1.0 cm3, and the values fitted a normal distribution curve. Assuming that there were no appreciable differences in size between the historic and recent mandibles, the mandibular symphysis can theoretically be used as a donor site in early secondary osteoplasty in about 92% of cleft patients to augment a cleft volume of 0.5 cm3, in 50% for a cleft volume of 1.0 cm3, and in 18% for a cleft volume of 1.5 cm3. With cleft volumes larger than 1.5 cm3, the symphysis can hardly be considered. If, however, a safety margin of 5 mm from the apices of the front teeth is maintained, the chance that the mandibular symphysis will suffice decreases for a 0.5 cm3 volume to 64%, for a 1.0 cm3 cleft to 3.5%, and for a 1.5 cm3 cleft to 0%.

[Temporomandibular ankylosis and progressive ossifying myositis. Review of the literature apropos of a case report]. / Ankylose temporomandibulaire et myosite ossifiante progressive. Revue de la littérature à propos d'un cas clinique.

A case of extraarticular temporomandibular ankylosis due to progressive ossifying myositis is reported. The local pathology appeared 13 years after the initial generalized symptomatic onset. CT scan helps to the diagnosis. Despite surgical therapy, the pathology reappears so we conclude to the unique efficiency of medical therapy: corticosteroids by pulse therapy. A review of the literature on the subject was made. A discussion ends the publication.

[Sleep apnea syndrome and hypothyroidism: apropos of a new case and a review of the literature]. / Syndrome d'apnée du sommeil et hypothydroïdie: à propos d'un nouveau cas et revue de la littérature.

We present the case of a 63 years old man (177 cm height, 111 kg weight) with autoimmune thyroiditis. He had a long term history of hypersomnolence and heavy snoring. Two years ago, because of a bifascicular block and sinus pauses, a cardiac pace-maker was placed. Polysomnography recording showed a systematic periodic breathing characterized by profound desaturation waves (often 92% Sa O2 to 60% Sa O2) every 60 seconds, secondary to prolonged mixed apneas. Hormone replacement therapy and a 17 kg weight loss completely suppressed the sleep apnea syndrome within five months. We conclude that SAS is a major component of the respiratory depression in hypothyroidism and that normalisation of thyroid function can definitely cure the patient.

Risk of lung, larynx, pharynx and buccal cavity cancers among carbon electrode manufacturing workers.

Among workers employed in factories producing carbon graphite products the risk of cancer due to exposure to polycyclic aromatic hydrocarbons was estimated. In one cohort (plant A), a cancer incidence study was carried out; the number of cases were not significantly increased for lung cancers [7 cases, standardized incidence ratio (SIR) 79] or for cancers of the upper respiratory and alimentary tract (10 cases, SIR 103). In another cohort (plant B), a mortality study was carried out; neither the mortality from lung cancer [13 deaths, standardized mortality ratio (SMR) 118] nor that from upper respiratory and alimentary tract cancers (10 deaths, SMR 125) was significantly higher than expected. Within each cohort, a case-referent study was carried out. In plant A the odds ratios were high but nonsignificant for lung cancers (odds ratio 3.42) and upper respiratory and alimentary tract cancers (odds ratio 2.19) and they showed a nonsignificant relationship with duration of exposure. In plant B, the odds ratios were low for every cancer site.

Mortality of aluminium reduction plant workers in France.

The mortality between 1950 and 1976 of 6455 French aluminium plant workers was analysed in order to assess occupational risks (especially lung cancer) associated with electrolysis, particularly with the Söderberg process. Mortality from all causes (SMR = 0.85), was lower in this cohort than in the French male population ('healthy worker effect'), and cancer mortality (SMR = 1.09) was only slightly higher. There was an excess of mortality from accidents (mainly non-occupational) in electrolysis workers (SMR = 1.38) and from cirrhosis of the liver in maintenance workers (SMR = 1.63). Among electrolysis workers, only those who had worked less than 10 years had a relative excess mortality from lung cancer (SMR = 1.94), but this did not seem to be associated with a particular electrolysis process. However a substantial underlying risk of lung cancer in Söderberg workers could not be excluded, although such a risk appeared unlikely for prebake workers.

[Review of the recent literature apropos of a case of Burkitt's lymphoma in the maxillofacial area]. / Revue de la littérature récente à propos d'un cas de lymphome de Burkitt à localisation maxillo-faciale.

A case is reported of a child of white race with a maxillofacial localization of Burkitt's lymphoma (BL), and recent published data on epidemiology, clinical and therapeutic aspects, histologic criteria and immunologic properties of this lymphoma reviewed. The association in Africa of BL with the Epstein-Barr virus, and with remarkably constant cytogenetic anomalies suggests the need to recall the oncogenetic hypotheses for this affection.

[Central or intercondylar luxation of the patella. Apropos of a case]. / Luxation centrale ou inter-condylienne de la rotule. A propos d'un cas.

A case of central (intercondylar) dislocation of the patella is reported. The displacement could be reduced easily. At surgery, the quadriceps tendon was found to be intact.

[Atloaxoid dislocation with basilar pressure and spinal cord symptoms in rheumatoid arthritis. A case of occipitocervical arthrodesis followed by resection of the odontoid]. / Luxation atloïdo-axoïdienne avec impression basilaire et signes médullaires au cours d'un rhumatisme inflammatoire chronique. 1 cas d'arthodèse occipito-cervicale suivie de résection de l'odontoïde.

The authors report a case of atlanto-axial dislocation in a patient with rheumatoid arthritis. There was some neurological impairment with upper limb pain and hyperreflexia. As a first stage, a cranio-cervical fusion was performed through a posterior approach. Three weeks later the axis was excised through an antero-lateral approach, together with its odontoid process. The patient's condition was much improved and the neurological lesions disappeared.