Metabolic profile of high intensity intermittent exercises

To evaluate the magnitude of the stress on the aerobic and the anaerobic energy release systems during high intensity bicycle training, two commonly used protocols (IE1 and IE2) were examined during bicycling. IE1 consisted of one set of 6-7 bouts of 20-s exercise at an intensity of approximately 170% of the subject's maximal oxygen uptake (VO2max) with a 10-s rest between each bout. IE2 involved one set of 4-5 bouts of 30-s exercise at an intensity of approximately 200% of the subject's VO2max and a 2-min rest between each bout. The accumulated oxygen deficit of IE1 (69 +/- 8 ml.kg-1, mean +/- SD) was significantly higher than that of IE2 (46 +/- 12 ml.kg-1, N = 9, p < 0.01). The accumulated oxygen deficit of IE1 was not significantly different from the maximal accumulated oxygen deficit (the anaerobic capacity) of the subjects (69 +/- 10 ml.kg-1), whereas the corresponding value for IE2 was less than the subjects' maximal accumulated oxygen deficit (P < 0.01). The peak oxygen uptake during the last 10 s of the IE1 (55 +/- 6 ml.kg-1.min-1) was not significantly less than the VO2max of the subjects (57 +/- 6 ml.kg-1.min-1). The peak oxygen uptake during the last 10 s of IE2 (47 +/- 8 ml.kg-1.min-1) was lower than the VO2max (P < 0.01). In conclusion, this study showed that intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally.     

Mechanisms of multidrug resistance in tumor cells and analytical methods for its detection

We reviewed mechanisms of multidrug resistance (MDR) phenotype in tumor cells and evaluated analytical methods for detection of clinical MDR. A well-recognized mechanism of MDR phenotype is the induction and increased expression of P-glycoprotein (P-gp) which is a 170 kDa cellular transmembrane protein encoded by a multidrug-resistance 1 gene (MDR1) and works as a drug efflux pump. Cellular MDR phenotype through P-gp/MDR1 can be detectable at protein level by: (1) using immunohistochemical method, flow cytometric assay and Western blot analysis with monoclonal antibodies against human P-gp, and (2) measuring Rhodamine 123 dye-efflux as a functional assay of P-gp. Molecular knowledge and recent technical progress enable to determine MDR1 gene expression by RT-PCR-based analytical methods as well as conventional quantification methods of gene expression such as Northern blot analysis. In the evaluation of P-gp/MDR1 expression in clinical samples, in which amount of materials was limited, utilization of simple and sensitive methods like competitive RT-PCR assay might be efficacious for its quantitative detection in clinical laboratories. Evidences which showed the positive correlation between the expression of P-gp/MDR1 and clinical resistance or refractoriness of tumor cells to anticancer drugs involved in MDR have been accumulated and support the clinical importance of its detection to circumvent resistance with alternate use of non-MDR drugs.     

Serum androgen levels in hyperthyroid women

PURPOSE: We retrospectively evaluated the results of combined phacoemulsification and trabeculectomy through scleral tunnel incision in comparison with those of goniotrephination alone. PATIENTS AND METHODS: 27 eyes of 20 patients (78.3 +/- 7.45 years) underwent a combined trabeculectomy and phacoemulsification with IOL-implantation (PT-group). The trabeculectomy was performed by excision of 2 mm middle part of the lower tunnel lip. In comparison with the TP-group 29 eyes of 28 patients (69.3 +/- 8.1 years) underwent a goniotrephination (Fronimopoulos), (G-group). The median of follow up was 8 weeks. RESULTS: In both groups a significant reduction of the IOP was achieved; in the PT-group the IOP was reduced from 31.0 +/- 5.42 to 15.0 +/- 4.5 mm Hg, in the G-group from 31.4 +/- 6.3 to 11.6 +/- 4.12 mmHg. In the PT-group the visual acuity increased significantly from 0.25 +/- 0.14 to 0.37 +/- 0.27 and decreased significantly from 0.46 +/- 0.28 to 0.32 +/- 0.25 in the G-group. 3 patients (= 11%) needed topical medication in the PT-group and 6 (= 24%) in the G-group. Four patients (= 15%) of the PT-group underwent a secondary surgery and 7 (= 24%) of the G-group. CONCLUSIONS: The combined phacoemulsification and trabeculectomy is a successful method of IOP control and visual rehabilitation. Due to the decrease of visual acuity and a higher frequency of secondary surgery after goniotrephination alone the combined procedure should be preferred even in presence of a moderately visual acuity reducing cataract.     

Light-harvesting in Acaryochloris marina--spectroscopic characterization of a chlorophyll d-dominated photosynthetic antenna system

Oxygenic photosynthesis of the prokaryote Acaryochloris marina involves chlorophyll d (Chl d) as the major pigment [Miyashita et al. (1996) Nature 383, 402]. Four spectral forms of Chl d (peak wavelengths: 694, 714, 726 and 740 nm) are resolvable by low-temperature absorption spectroscopy on intact cells. Based on fluorescence spectra (at 290 K and 77 K) and on analysis of fluorescence induction curves we conclude: (1) excitation energy is efficiently transferred between the various spectral forms of Chl d and the PS II reaction center; (2) Chl d serves as a light-harvesting pigment for both, Photosystem II (PS II) and PS I; (3) excitation energy transfer between PS II units occurs.     

Response of acoustic signals generated in water by energetic xenon ions

The acoustic signals generated by bombarding 400 MeV/n xenon ions in water were studied using an array of piezoelectric lead–zirconate–titanate elements. The observed signal was reduced to a bipolar form through Fourier analysis. The output voltage corresponded to the amount of energy deposit in water, and it tailed off beyond the range of 400 MeV/n xenon in water. This magnitude was explained qualitatively as cumulative processes. Its behavior was consistent with the calculations based on the Bethe–Bloch formula. Possible applications of this detector to radiology and heavily doped radiation detectors are described.     

Stabilization of acrylic fibers by sulfur atoms mechanism of stabilization

The conventional process for making carbon fibers from PAN fibers includes a preliminary step of oxidizing the fibers in order to stabilize the polymer prior to pyrolysis where oxygen atoms are incorporated into the polymer. We have found that the introduction of sulfur atoms can also stabilize the PAN fibers. It was concluded that the essential step of the stabilization of acrylic fibers is the formation of active sites by the incorporation of hetero atoms into the polymer to initiate polymerization of nitrile groups to form the condensed heterocylic ring structure. The kinetics of stabilization reaction were studied and it was found that stabilization is a first order reaction with activation energy of 30 kcal · mol^?1. The chemistry and the mechanism of the stabilization is proposed.     

A Low-Noise Terahertz SIS Mixer Incorporating a Waveguide Directional Coupler for LO Injection

We have developed a low-noise heterodyne waveguide Superconductor-Insulator-Superconductor (SIS) mixer with a novel local oscillator (LO) injection scheme for the Atacama Large Millimeter/submillimeter Array (ALMA) band 10, over the frequency range 0.78–0.95 THz. The SIS mixer uses radio frequency (RF) and LO receiving horns separately and a waveguide 10 dB LO coupler integrated in the mixer block. The insertion loss of the waveguide and coupling factor of the coupler were evaluated at terahertz frequencies at both room and cryogenic temperatures. The double-sideband (DSB) receiver noise temperatures were below 330 K (7.5hf/k _B) at LO frequencies in the range 0.801–0.945 THz. The minimum temperature was 221 K at 0.873 THz over the intermediate frequency range of 4–12 GHz at an operating temperature of 4 K. This waveguide heterodyne SIS mixer exhibits great potential for practical applications, such as high-frequency receivers of the ALMA.