[An influence of the modified therapy on the course of epilepsy in patients with the low cerebral spinal fluid-cranial index]. / Vliianie modifitsirovannoi terapii na techenie épilepsii u bol'nykh s nizkim likvoro-kranial'nym indeksom.

AIM: To evaluate the effect of modified therapy on the course of epilepsy in patients with the low cerebral-spinal-fluid-cranial (CSF-cranial) index. MATERIAL AND METHODS: One hundred and twenty-four patients with cryptogenic epilepsy were prospectively analyzed. Group I consisted of 36 patients with a normal volume of reserve cerebrospinal fluid and a level of the CSF-cranial index within the physiological norm (from 1.2 to 3.6), who received standard therapy. Group II consisted of 42 patients with a small volume of reserve cerebrospinal fluid spaces and a CSF-cranial index lower than the physiological norm (from 0.8 to 1.2), who received standard therapy. Group III (n=46) was characterized by a small volume of reserve cerebrospinal spaces and a CSF-cranial index lower than the physiological norm. Patients of this group received modified therapy. RESULTS AND CONCLUSION: Normalization of the level of intracranial pressure in patients with a low cerebrovascular index reduced the frequency of epileptic seizures. After one year follow-up, the proportion of patients with very frequent seizures decreased by 25.3%, with frequent seizures by 23.9%, after 2 years by another 33.1 and 15.7%, respectively. A correlation was found between the frequency of seizures and the level of intracranial pressure (G=0.24, p=0.043).

Chirp measurement of multimode q-switched laser diode pulses by use of a streak camera and a grating monochromator.

We discuss spectrotemporal measurements of laser diode pulses performed with a streak camera and a grating monochromator to yield a precise evaluation of chirping effects in Q-switched multimode emissions. We experimentally illustrate several causes of errors, depending on the grating size and period as well as on the adjustment of the collimating lens at the monochromator output. An analytical formula is derived that allows us to relate the chirp amplitude to the inclination of the modal structures in the streak image. Two configurations are proposed for a practical determination of the chirp amplitude in multimode emissions. Illustrations are provided with Q-switched AlGaAs laser diodes that exhibit chirp amplitudes larger than the mode spacing.

Tunable picosecond blue and ultraviolet pulses from a diode-pumped laser system seeded by a gain-switched laser diode.

Picosecond pulses emitted from a gain-switched laser diode have been amplified in a Ti:sapphire regenerative amplifier indirectly pumped by a 4-W laser diode. This all-solid-state system produced microjoule pulses tunable from 803 to 840 nm at repetition rates up to 25 kHz with durations of 70-100 ps. By frequency doubling and tripling the output, we generated blue and UV pulses tunable from 401 to 420 nm and from 268 to 280 nm, respectively. Average powers larger than 4 mW were reached in these two wavelength regions.