BACKGROUND The use of photoactivated disinfection has had a significant medical and technological effect in bacterial inactivation, as an alternative to conventional antimicrobial methods. The main goal of this study was to investigate the effect of photoactivated disinfection on Streptococcus mutans, when Radachlorin(®) was used as a photosensitizer. METHODS Streptococcus mutans samples of t...

A fiber sensor system based on high-birefringence optical fiber and a frequency-stabilized He-Ne Zeeman laser (lambda = 0.6328 microm) has been demonstrated. The small path-length changes of interest are extracted from the amplitude or phase of the laser beat frequency by using either the phase-sensitive detection or the phase-demodulation technique. A minimum detectable optical phase delay of ...

He-Ne laser irradiation (0.01 -6 3/cm3) of the blood and neutrophile suspension in vitrowas shown to modulate reactive oxygen species (RDS ) product ion in healthy donors. Intravascular laser irradiation of the blood ( 5 mW, 30 minutes, daily) of the patients with chronic gastric ulcer during first 5 days resulted in increasing stimul-k-duced ROS production in patients with the low initial chem...

Mid-infrared laser lines observed in hydrogen/rare gas discharges are assigned to three-body recombination processes involving an electron, a rare gas (He or Ne) atom, and the triatomic hydrogen ion (H(3)(+)). Calculations of radiative transitions between neutral H(3) Rydberg states support this interpretation, and link it to recent results for hydrogenic∕rare gas afterglow plasmas. A mechanism...

Arsenic chalcogenide microlenses (As2S3) produced by an original procedure have been used for focusing the red – infrared laser light direct through an optical fiber. The microlenses with diameter in the range 150 – 400 m were glued on the optical single-mode fiber ends by Canada balm under optical microscope. The focusing effect of the microlenses was investigated in a stereomicroscope, and th...

We report an efficient, visible, nanosecond optical parametric generator of periodically poled lithium niobate pumped at 532 nm by a frequency-doubled, diode-pumped, passively Q -switched, single-mode Nd:YAG laser with 90-muJ pulse energy. The signal radiation is tunable from 637 to 593 nm. The maximum signal-conversion efficiency is 23%. Optical parametric amplification of a He-Ne laser at 632...

In this contribution we focus on laser frequency noise properties and their influence on the interferometric displacement measurements. A setup for measurement of laser frequency noise is proposed and tested together with simultaneous measurement of fluctuations in displacement in the Michelson interferometer. Several laser sources, including traditional He-Ne and solid-state lasers, and their ...

We explore the properties of atoms confined to the interstitial regions within a carbon nanotube bundle. We find that He and Ne atoms are of ideal size for physisorption interactions, so that their binding energies are much greater there than on planar surfaces of any known material. Hence high density phases exist at even small vapor pressure. There can result extraordinary anisotropic liquids...

Introduction: Trapped noble gases were discovered in chon-drules by laser microprobe noble gas analysis [1-3]. The observed noble gases were explained by solar gas acquisition in dust grains before the chondrule formation [1-3]. These results show importance of trapped noble gases in chondrites to understand environment and formation processes of chondrules. We performed the laser microprobe no...