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Tanaka, T., Y. Ohira, M. Danda, H. Hatta, and I. Nishi.Improved fatigue resistance not associated with maximum oxygen consumption in creatine-depleted rats. J. Appl. Physiol.82 (6): 1911–1917, 1997.—Effects of feeding of either creatine or its analog β-guanidinopropionic acid (β-GPA) on endurance work capacity and oxygen consumption were studied in rats. Resting high-energy phosphate contents in hindlimb muscles were lower in the β-GPA group and higher in the creatine group than in controls. The glycogen contents in resting hindlimb muscles of rats fed β-GPA were significantly higher than those in controls. The endurance run and swimming times to exhaustion were significantly greater (32–70%) in the β-GPA group than in the control and creatine groups. However, there were no beneficial effects on the maximum oxygen consumption (V˙o2 max) and oxygen transport capacity of blood by the feeding of β-GPA. None of these parameters were significantly influenced by creatine supply. Both maximum exercise time andV˙o2 maxin the β-GPA group were not changed by normalization of glycogen levels. The activities of mitochondrial enzymes in skeletal muscles were higher in the β-GPA group than in the controls. Thus endurance capacity is improved if the respiratory capacity of muscles is increased, even when the contents of high-energy phosphates in muscles are lower. Increased endurance capacity was not directly associated with the elevated levels of muscle glycogen, oxygen transport capacity of blood, orV˙o2 max.

0.8 μm band laser-diode modules have been developed for coupling to fibres with a relative refractive-index difference (δ) as high as 2.3%. A coupling loss of 3.1 dB, fibre output power over 35 mW, and excellent temperature stability in the range from –10 to 60°C were realised using a thermally-diffused expanded core fibre.

Novel 10-fibre connectors have been developed based on a magnetic self-aligning mechanism. The magnetic-alloy-clad fibres for the connector are attracted into V-grooves by a permanent magnet. The average connection loss is 0.4 dB with index matching. The loss for each connection point remains constant within a deviation of 0.005 dB, the measurement accuracy, for disengagement/re-engagement cycles with the connector.

11 channel optical-frequency-division multiplexing with a 10 GHz channel spacing is achieved with an arrayed-waveguide grating consisting of SiO2–GeO2/SiO2 waveguides on a silicon substrate.

A small fibre amplifier module pumped by a 0.98 μm LD has been fabricated. Using a low erbium content fibre with a 4.9 dB/mW gain coefficient, the module attained 33 dB gain at 1.535 μm with only 80 mA drive current.

A novel diffraction grating based on arrayed channel waveguides has been proposed for nanometre-spaced wavelength division multiplexing. A grating with a diffraction order of 20 has been fabricated using a composite glass waveguide. A wavelength resolution of 0.63 nm has been achieved in the 1.3 μm wavelength band.

The letter describes the experimental results of a novel optical filter for a multi/demultiplexer using a diffraction grating and a retroreflector prism. A broader passband width, which is proportional to the difference between the prism base length and the input fibre core diameter, is obtained. The minimum insertion loss is 2.2 dB.