Fiber optic micro sensor for the measurement of tendon forces.

A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain.

For whales and seals the ocean is not blue: a visual pigment loss in marine mammals.

Most terrestrial mammals have colour vision based on two spectrally different visual pigments located in two types of retinal cone photoreceptors, i.e. they are cone dichromats with long-to-middle-wave-sensitive (commonly green) L-cones and short-wave-sensitive (commonly blue) S-cones.

Excimer laser micromachining for rapid fabrication of diffractive optical elements.

We demonstrate the fabrication of binary, multilevel, and blazed diffractive structures by a fast and flexible direct-write process by using an excimer-laser-based tabletop micromachining workstation with an integrated optical surface profiler.

Chronobiology of indoleamines in the dinoflagellate Gonyaulax polyedra: metabolism and effects related to circadian rhythmicity and photoperiodism.

The marine bioluminescent dinoflagellate Gonyaulax polyedra is capable of producing various indoleamines. The first enzyme in their formation, tryptophan hydroxylase, exhibits a high-amplitude circadian rhythm with a maximum during photophase. Hydroxyindole-O-methyltransferase shows a biphasic pattern with a major maximum during scotophase.

On the primary functions of melatonin in evolution: mediation of photoperiodic signals in a unicell, photooxidation, and scavenging of free radicals.

Melatonin is widely abundant in many eukaryotic taxa, including various animal phyla, angiosperms, and unicells. In the bioluminescent dinoflagellate Gonyaulax polyedra, melatonin is produced in concentrations sometimes exceeding those found in the pineal gland, exhibits a circadian rhythm with a pronounced nocturnal maximum, and mimics the short-day response of asexual encystment. Even more efficient as a cyst inducer is 5-methoxyptryptamine (5MT), which is also periodically formed in Gonyaulax.

Immunocytochemical demonstration of astrocytes and microglia in the whale brain.

Whale brains have attracted the attention of neuroscientists but there are only sparse studies on whale glial cells. Here we report on immunolabeling of astrocytes by antibodies to glial fibrillary acidic protein (GFAP) or protein S-100 beta (both by the streptavidin/biotin technique), and labeling of microglial cells by Griffonia simplicifolia agglutinin (GSA I-B4, coupled to horseradish peroxidase), in the neocortex of a harbour porpoise Phocoena phocoena L. Many subpial and perivascular astrocytes were stained; they differed greatly in thickness and length of their processes.

Influence of temperature on diffractive lens performance.

The thermal properties of lenses play an important role in the performance of optical systems. We discuss the effects of uniform temperature changes and thermal gradients on diffractive lens performance. Comparisons are made between the thermal sensitivity of refractive and diffractive lenses.