Laser heating of uncoated optics in a convective medium.

Powerful, long-pulse lasers have a variety of applications. In many applications, optical elements are employed to direct, focus, or collimate the beam. Typically the optic is suspended in a gaseous environment (e.g., air) and can cool by convection. The variation of the optic temperature with time is obtained by combining the effects of laser heating, thermal conduction, and convective loss. Characteristics of the solutions in terms of the properties of the optic material, laser beam parameters, and the environment are discussed and compared with measurements at the Naval Research Laboratory, employing kW-class, 1 µm wavelength, continuous wave lasers and optical elements made of fused silica or BK7 glass. The calculated results are in good agreement with the measurements, given the approximations in the analysis and the expected variation in the absorption coefficients of the glasses used in the experiments.

Neonatal middle cerebral artery infarction: association with elevated maternal anticardiolipin antibodies.

A full-term neonate was born to a 41-year-old woman via elective primary cesarean section for frank breech presentation after a 41-week pregnancy. Starting at 6 hr of age the infant presented with multiple episodes of apnea and cyanosis, in association with moderate hypotonia, subsequently requiring assisted ventilatory support for 2 days. Computerized axial tomography of the brain revealed infarction in the distribution of the left middle cerebral artery. Magnetic resonance imaging of the brain showed a left middle cerebral artery territory infarct and also a small right posterior-temporal infarct. Magnetic resonance angiography of the head and neck was normal, however, inferring that the vascular infarction was peripheral in location. Maternal anticardiolipin antibodies were elevated. This is only the fifth reported case of cerebral infarction in a newborn in association with elevated maternal anticardiolipin antibodies.

[An atypical case of Aujeszky's disease in a dog (author's transl)]. / Een atypische vorm van de ziekta van Aujerzky bij een hand

Two cases of Aujeszky's disease in a cat and a dog belonging to the same owner are reported. The two animals each were five months of age. The symptoms shown by the cat were typical of Aujeszky's disease: intense itching, salivation and the head bent to one side. The main symptoms shown by the dog consisted in salivation, ptosis of one eye, a drooping ear, the head bent to one side and ataxia. As itching was not observed in the dog and the animal had spent the first months of its life in wooded surroundings, it could also have been affected with rabies, although it had been inoculated with LEP-Flury vaccine forty days prior to importation. It is of importance to the practitioner to know that itching may be absent in dogs with Aujeszky's disease and that rabies should also be suspected in these cases. Only a laboratory diagnosis will be conclusive. Studies were negative for rabies, the virus of Aujeszky's disease being found to be present in the two cases. The source of infection probably consisted in contaminated pork offal (larynges).