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It is often observed in industrial practice that the thickness uniformity of blown film obtained with a given die varies with the type of polymer. We have shown in previous works the importance of the wall slip of polymer melt in the film uniformity. Currently available models of polymer melt flow through spiral mandrel dies neglect the wall slip. The present work considers the slip in flow analyses and predicts the effects of rheological properties on the uniformity; the decreases in melt viscosity and wall slip and the increases in shear thinning and the stress dependence of wall slip reduce the uniformity. The predictions agree well with the experimental results obtained in our previous studies.

The forearm muscles of five healthy males were monitored for changes in microvessel hemoglobin saturation (SO2-TRS) by near infrared time-resolved spectroscopy (NIRTRS) and changes in phosphorus metabolites by magnetic resonance spectroscopy (31P-MRS) during 12 min of resting arterial occlusion. Muscle oxygenation and phosphorus metabolites were also measured during grip exercises at varying intensities. Upon the initiation of occlusion, SO2-TRS fell progressively until it reached a plateau in the latter half of the occlusion. Phosphocreatine (PCr) began to decrease around 6 min after the initiation of arterial occlusion. The resting O2 store and O2 consumption were 295 μM and 0.95 μM/sec, respectively-values which reasonably agree with the reported results. A significant correlation was observed between the changes in SO2-TRS and PCr during exercise (r2 = 0.80, p < 0.001). These results indicate that NIRTRS is able to provide reliable information about resting metabolism and oxidative rate during exercise. NIRTRS and MRS are useful to monitor oxygenation and energetics noninvasively in the human muscle.

Studies on mercury levels in the Amazonian Region have typically lacked background or reference parameters. A sectional study on Hg concentration in hair and fish was conducted, together with an assessment of the prevalence of signs and symptoms related to Hg poisoning, in four communities in the Amazon Basin not impacted by gold mining, located either by a river course (Santana do Ituqui and Caxiuanã) or by a lake (Aldeia do Lago Grande and Vila do Tabatinga). Mercury determinations in hair and fish were made by flameless atomic absorption spectrophotometry. Mean total Hg in hair was 4.33 microg/g (0.40-11.60 microg/g) in 321 individuals from Santana do Ituqui, 3.98 microg/g (0.40-11.76 microg/g) for 316 persons in Aldeia do Lago Grande, 5.46 microg/g (0.37-49.85 microg/g) for 504 individuals from Vila do Tabatinga and 8.58 microg/g (0.61-45.59 microg/g) for 203 inhabitants from Caxiuanã. Fish consumption was very high in all those communities but no signs or symptoms associated with Hg poisoning were found. Mean Hg concentration in fish varied from 0.006 to 2.529 microg/g for carnivores and from 0.008 to 0.871 microg/g for noncarnivores. These values suggest that further studies including a larger number of communities would eventually lead to values of "normal" Hg concentration in the Amazonian Region quite above the limits suggested by the World Health Organization.

Minist?rio da Sa?de. Funda??o Servi?os de Sa?de P?blica. Instituto Evandro Chagas. Bel?m, PA, Brasil. Minist?rio da Sa?de. Funda??o Servi?os de Sa?de P?blica. Instituto Evandro Chagas. Bel?m, PA, Brasil. Minist?rio da Sa?de. Funda??o Servi?os de Sa?de P?blica. Instituto Evandro Chagas. Bel?m, PA, Brasil. Rio de Janeiro Federal University. Center for Studies in Public Health. Rio de Janeiro, RJ, Brazil. Minist?rio da Sa?de. Funda??o Servi?os de Sa?de P?blica. Instituto Evandro Chagas. Bel?m, PA, Brasil. Executive Secretariat of Industry, Commerce and Mining. Bel?m, PA, Brazil. Minist?rio da Sa?de. Funda??o Servi?os de Sa?de P?blica. Instituto Evandro Chagas. Bel?m, PA, Brasil. AMBIOS - Engeneering and Processes. S?o Paulo, SP, Brazil. Municipal Secretariat of Health. Rio Branco, AC, Brazil. Rio de Janeiro Federal University. Center for Studies in Public Health. Rio de Janeiro, RJ, Brazil. Em?lio Goeldi Paraense Museum. Bel?m, PA, Brazil.

In order to obtain the information about plutonium contamination in ocean environment, plutonium in the internal organs of squid collected from Japanese inshore were determined by HR-ICP-MS. Although the plutonium was detected in all samples collected in 1980"""s, the concentration is almost the same level as the detection limit (1 to 3 mBq/kg wet) in recent years. The atomic ratio of 240Pu/239Pu in all samples was slightly higher than the value of global fallout.

Highly transparent, low-resistance SnO 2 :F films suitable as a substrate material for thin-film CdS/CdTe solar cells have been developed on 10 × 10, 30 x 60 and 82 x 71 cm 2 glass substrates by an ultrasonic spray pyrolysis (pyrosol) process. Dimethyltin dichloride, NH 4 F and HF dissolved in water served as the source solution. A fine spray of the source solution has been transported using air as a carrier gas onto hot glass plates in a belt furnace maintained at 500-530°C. A very high growth rate of > 15 nm/s and a high throughput of 3 min/glass plate (82 x 71 cm 2 size) have been achieved with films showing greater uniformity, low sheet resistance and high optical transmission. Typical films exhibited a thickness of 500 nm, a sheet resistance of 8.1 Ω/sq., a mobility of 43.8 cm 2 /V s and a donor concentration of 3.5 x 10 20 cm -3 . A thin-film CdS/CdTe solar cell fabricated on a 30 x 60 cm 2 SnO 2 :F transparent conducting substrate exhibited a solar energy conversion efficiency maximum of 14.95% for 1 cm 2 cell and an average efficiency of 14.24% for 178 isolated 1 cm 2 cells.

Highly efficient large area (10.5%, 1376 cm2) thin-film CdS/CdTe solar cell sub-module has been fabricated. Very recently we also have fabricated a very large area sub-module of aperture area 5413 cm2 exhibiting a conversion efficiency of 8.4%. Such a high efficiency has been achieved by depositing all the constituent films such as SnO2: F, CdS and CdTe having greater uniformity and better quality under atmospheric pressure conditions. A post deposition treatment of CdTe surface with CdCl2 has been optimized to improve the overall solar cell output performance significantly.

The purpose of this study was to examine the validity of the quantitative measurement of muscle oxidative metabolism in exercise by near-infrared continuous-wave spectroscopy (NIRcws). Twelve male subjects performed two bouts of dynamic handgrip exercise, once for the NIRcws measurement and once for the 31P-magnetic resonance spectroscopy (MRS) measurement as a standard measure. The resting muscle metabolic rate (RMRmus) was independently measured by 31P-MRS during 15 min of arterial occlusion at rest. During the first exercise bout, the quantitative value of muscle oxidative metabolic rate at 30 s postexercise was evaluated from the ratio of the rate of oxyhemoglobin/myoglobin decline measured by NIRcws during arterial occlusion 30 s after exercise and the rate at rest. Therefore, the absolute values of muscle oxidative metabolic rate at 30 s after exercise [V˙o 2NIR(30)] was calculated from this ratio multiplied by RMRmus. During the second exercise bout, creatine phosphate (PCr) resynthesis rate was measured by 31P-MRS at 30 s postexercise [Q(30)] under the same conditions but without arterial occlusion postexercise. To determine the validity of NIRcws, V˙o 2NIR(30) was compared with Q(30). There was a significant correlation betweenV˙o 2NIR(30), which ranged between 0.018 and 0.187 mM ATP/s, and Q(30), which ranged between 0.041 and 0.209 mM ATP/s ( r = 0.965, P < 0.001). This result supports the application of NIRcws to quantitatively evaluate muscle oxidative metabolic rate in exercise.

We present the results of a theoretical and vibrational spectroscopic study carried out on three different 2,2 ′(dihexyl-2,2′,5,5′-tetrahydro-2,2′-bithienylidene-5,5′-diylidene)bis(propanedinitrile) isomers, which are compared with the corresponding unsubstituted bithienoquinonoid in the pristine state as solids. In these isomers, the two solubilizing hexyl side chains are attached to preassigned ‚-positions: head-to-head (HH), head-totail (HT), and tail-to-tail (TT). These materials possess a highly extended ﷿-electron conjugation, since they bear a pure heteroquinonoid structure in their electronic ground states. Thus, these molecules could be regarded as suitable models of the structural perturbations induced by the ionization in doped polythiophene.

Spectroscopic properties of Nd 3+ and Ho 3+ in a Ga 2 S 3 –GeS 2 –La 2 S 3 glass system were investigated on the basis of the Judd–Ofelt analyses for 60GaS 3/2 · 10GeS 2 · 27LaS 3/2 · 3LnS 3/2 glasses (Ln=Nd or Ho) and emission lifetime measurements for 60GaS 3/2 · 10GeS 2 · 29.7LaS 3/2 · 0.3LnS 3/2 glasses (Ln=Nd or Ho). The obtained Judd–Ofelt Ω 2 parameter for Nd 3+ was larger than those of other glass systems such as oxides and fluorides. For Ho 3+ , on the other hand, the Ω 2 parameter was so small that it could not be determined with enough accuracy. Non-radiative transition rates for 4 G 5/2 and 2 K 13/2 levels of Nd 3+ and 5 F 5 and 5 S 2 levels of Ho 3+ were obtained by the difference between the inverse of the measured emission lifetimes and the calculated radiative transition rates of these levels. The non-radiative transition rate of the 5 S 2 of Ho 3+ was about one order larger than predicted from the so called `energy-gap law'. We assumed that the energy transfer from the 5 S 2 of Ho 3+ to an electronic state of the host glass occurs. Multiphonon relaxation rates were comparable with those of a ZnCl 2 -based glass.

This investigation was performed to examine qualitatively and quantitatively the reverse flow in partially dried roots of Sesbania rostrata using the constant power heat balance method. First, a semi-empirical technique for estimating sheath conductance of sap-flow sensors without assuming that sap flow is zero at night was proposed. Sap flow measured with the heat balance method was compared with water uptake as measured by a potometric method. Sap flow was overestimated by 56·1% for a 3·3-mm-diameter root, and by 40·0% for 6·1 mm and 33·3% for 8·8 mm roots. However, high correlation coefficients between the rates of water uptake and sap flow demonstrated that calibration would provide reliable values for root sap flow. To detect reverse flow, a split root experiment was conducted using a S. rostrata plant with its root system divided between dry and wet compartments. Daily sap flow of the drying compartment declined whereas that in ‘wet’ root increased, suggesting that the decrease in water uptake by ‘dry’ roots was offset by the ‘wet’ roots. Reverse flow was observed at night in the root on the dry side of the container when the soil water potential was less than –0·30 MPa. The total amount of water released into the soil during the night period was estimated to be 22·5 g.

The dependence of the leakage current in 1.3-/spl mu/m InGaAsP buried heterostructure (BH) lasers with p-n-p-n current blocking layers on well number, mesa width, and carrier density has been analyzed using a two-dimensional device simulator and compared with the electroluminescence (EL) emitted from InP layers. The analysis of the minority carrier flow reveals that the electron current flowing through the p-n-p-n current blocking layers is the dominant component of the leakage current. The measured EL intensity has two peaks at both sides of the n-blocking layer apart from the active layer. The EL intensity decreases with increasing well number and carrier density of the p-blocking layer, and increases with increasing mesa width. These results are consistent with the simulations.

The threshold current and the characteristic temperature of 1.3-/spl mu/m InGaAsP-InP buried heterostructure (BH) lasers with the p-n-p-n blocking layers have been numerically analyzed using a two-dimensional (2-D) device simulator. The simulation model includes optical gain, intervalence absorption, radiative spontaneous-emission current. Auger recombination current, Shockley-Read-Hall recombination current, and heterobarrier leakage current. In addition to these components, the leakage current flowing through the p-n-p-n blocking layer which was ignored so far is also included. The analysis of the current components reveals that the increase in the threshold current with temperature is due to Auger recombination and the leakage current through the p-n-p-n blocking layer. The calculated T/sub 0/ value containing all the components is 54 K at room temperature and 29 K above 80/spl deg/C, which is consistent with observed T/sub 0/ values. When the leakage current through the p-n-p-n blocking layer is ignored in the calculation, the T/sub 0/ value is improved to 90 K and a decrease in the T/sub 0/ value is not observed. This result is consistent with conventional calculations. When Auger recombination is ignored. the T/sub 0/ value increases to 110 K at room temperature. However, the threshold current increases beyond the exponential relationship I/sub th/=I/sub 0/ exp(T/T/sub 0/) and the T/sub 0/ value decreases to 34 K at high temperature. This is due to a large increase rate of the leakage current through the p-n-p-n blocking layer. The reduction of Auger recombination is effective in decreasing the threshold current while the reduction of the leakage current through the p-n-p-n blocking layer is effective in improving T/sub 0/ values at high temperature, since T/sub 0/ values correspond to the increase rate of the threshold current.

Spectroscopic properties of Er3+ in Ga2S3–GeS2–La2S3 glasses are investigated on the basis of the spontaneous emission probabilities calculated by the use of the Judd–Ofelt theory and lifetime data. Frequency upconversion spectra are also measured with excitation at 800 and 980 nm. The spontaneous emission probabilities are much larger than those of the other glass systems such as oxides and fluorides. This is mainly attributed to the large refractive indices of the sulfide glasses. The quantum efficiencies of 4I11/2 and 4F9/2 levels are comparable or larger than the typical values of Er3+ in a fluoride glass. This is a consequence of the large spontaneous emission probabilities and low phonon energies of the sulfide glasses. However, the quantum efficiency of the 4S3/2 level is less than one-half of the value in the fluoride glass. The nonradiative transition probability of the 4S3/2 level is much larger than the value which is evaluated from the multiphonon relaxation theory. This suggests the presence ...

Strained-layer multiquantum-well distributed-feedback (MQW-DFB) lasers at a wavelength of 1.3 /spl mu/m operating from -40/spl deg/C to 85/spl deg/C without any coolers are demonstrated. Extremely low threshold current of 17 mA at 85/spl deg/C and operation current of 37 mA at 5 mW and 85/spl deg/C are obtained. To the best of our knowledge, each of them is the lowest value so far reported in InGaAsP-InP based DFB lasers. The lasers also realize low distortion of less than -50 dBc at 65/spl deg/C in 78-channel composite second order distortion (CSO) measurements. An experimental estimation of the leakage current in buried heterostructure presents that the distortion at high temperatures is mostly dominated by the carrier overflow from an active layer, not by the leakage current flowing through current blocking layers. On the basis of the leakage current analysis, a laser structure including the active layer and the current blocking layer is chosen to achieve low distortion over a wide-temperature-range. The uncooled distributed-feedback (DFB) laser we have developed is very useful for several channel transmission in CATV systems.

“Thorotrast” was widely used in the past as an X-ray contrast medium, containing a colloidal solution of thorium dioxide (232ThO2). After injection, thorium accumulates and is mainly retained in the liver. Thus once Thorotrast is administered, patients might be chronically exposed to α-radiations. Recently, significant development of cirrhosis and cancer of the liver has often been noted among Thorotrast patients. Additionally the incidence of lung and breast disease has significantly increased. Thus, the assessment of internal radiation dose from deposits of Thorotrast is very important. In this report, the thorium content in various organs was determined by means of neutron activation analysis. All the samples were taken from organs of Thorotrast patients subsequent to death. The ashed samples were irradiated in a reactor. After cooling, the content of thorium was determined by measurement of gamma rays resulting from the decay of protactinium-233. For comparison, measurements by other analytical methods such as inductively coupled plasma mass spectrometry, colorimetric analysis using ArsenazoIII and radiation measurement of γ-rays from actinium-228, were carried out.

Sulfide glasses of 50GaS3/2⋅20GeS2⋅20LaS3/2⋅10LnSn/2 (Ln=rare earth ions, n=2 for Eu and 3 for other ions) compositions have been prepared. The wavelength dispersions in the Faraday effect of the glasses have been examined. Glasses containing LaS3/2 and YS3/2 have positive Verdet constants in the wavelength region from 550 to 850 nm, and the magnitude of the Verdet constants decreases with increasing wavelength. On the other hand, the Verdet constants of glasses containing Eu2+ and Ce3+ are negative, and the absolute magnitude of the Verdet constants decreases with increasing wavelength. The effective transition wavelengths of glasses containing various paramagnetic rare‐earth ions have been calculated based on the Van Vleck and Hebb theory. Factors determining the Verdet constants of these glasses are discussed.

Heteroepitaxial p+-Si1−xGexn-Si(100) structures have been formed by the ArF excimer laser-induced melt-regrowth technique. Ge films are deposited on n-type Si(100) substrates by photochemical vapor deposition using an ArF excimer laser (λ = 193 nm) with tetraethylgermanium. Thin boron films are deposited on the Ge film using laser photolysis of B2H6. Successive 0.7 J/cm2 laser pulse irradiation initiates rapid melting near the surface and mixing of B/Ge/Si to form a B-doped heteroepitaxial p+-Si1−xGexn-Si(100) structure. The 〈001〉 axis of the alloy layers is oriented toward Si(100). Ge fractions in the alloy layers depend on Ge film thickness and the number of melting pulses. The total quantity of B incorporated into the alloy layers can be controlled by varying the number of deposition pulses at the B film deposition stage. The sheet resistance of a B-doped Si1−xGex (x < 0.04) alloy layer can be reduced to 20 Ω/□.

We have investigated, in terms of the Cohen-Turnbull theory, a relationship for polycarbonate (PC) glasses between average stress relaxation times, , and average free volume sizes, , obtained from positron annihilation lifetime spectroscopy. This examination suggests that the minimum free volume required for stress relaxation, υ*, decreases with decreasing temperature and that, near the glass transition temperature, only a subset of extremely large free volume elements contributes to the stress relaxation of PC glasses. This suggestion is consistent with the idea that near the glass transition temperature, the viscoelastic response is dominated by large-scale, main-chain motion, whereas at lower temperature it is controlled by local motion. Moreover, comparison with the υ* value estimated from gas diffusivity through various PC species at room temperature shows that the required free volume size for stress relaxation in the glass transition region is much larger than that for gas diffusion. Previously we showed that the Doolittle equation fails to correlate viscoelastic relaxation times of polymer glasses with changing temperature ; determining the free volume fraction, h, from theoretical analysis of volume recovery data and theory, the Doolittle equation is shown to be valid in PC above 135°C (T g - 14°C) irrespective of temperature and physical aging times. This result supports the idea suggested in the previous article that, as glassy polymers approach the transition region, viscoelastic properties increasingly tend to be controlled by free volume.

CdS/CdTe solar cells have attracted attention recently for their potential as low-cost, high-efficiency solar cells of the future. It is because the CdTe layer (used for photoelectric conversion) has a bandgap energy of 1. 51 eV, which corresponds well to sunlight spectra, and the direct transition type energy band structure enables formation of thinner films. We have already industrialized CdS/CdTe solar cells in mass production stage using a printing-sintering process, as large-area modules for electric power generation(Higuchi et al. , 1993, Omura et al. , 1991), and as cells for indoor applications (primarily in calculators. Suyama et al. , 1986). However, this solar cell has a conversion efficiency of approximately 6%. Recently, there has been considerable research into thin-film CdS/CdTe solar cells which have a thinner CdS film formed by CVD or CBD (Britt et al. , 1993) process, and thus are photosensitive to light with wavelengths of 500 nm or less. At present stage of our art, in solar cells formed by the CSS with a CdTe film on CVD CdS, a conversion efficiency of 15. 05% has been obtained in cells with an area of 1 cm2 (verified at JQA).

The dependence of physical properties on temperature and thermal history of glassy polycarbonate is examined. The average stress relaxation time increases during isothermal aging and with decreasing cooling rate. The temperature dependence of the stress relaxation time was compared with a free volume function calculated from specific volume data reported by Zoller by means of the Simha-Somcynsky theory and with a fractional free volume measured by ortho-positronium annihilation. We report in addition comparisons between free volume fractions extracted from volume data, and creep measurements for polystyrene, and stress relaxation data for poly(vinyl acetate) given by Kovacs et al., Schwarzl and Zahradnik, and Meyer et al. These investigations suggest that in the glassy state the Doolittle equation is valid only in isothermal aging experiments. It follows that in expressing the polymer mobility not only a temperature-dependent free volume but additional temperature-dependent processes need to be considered. © 1995 John Wiley & Sons, Inc.

Glass formation in binary M x S y -La 2 S 3 (M = Ga, Ge or As) systems was examined. Glasses were obtained for M = Ga whereas the M = Ge and As systems were not vitrifiable. In a ternary Ga 2 S 3 -GeS 2 -La 2 S 3 system, glasses were obtained by a substitution of 35 mol% of GeS 2 for GaS 3/2 . For the first time, upconversion luminescence of sulfide glass was measured for Er 3+ -doped Ga 2 S 3 -GeS 2 -La 2 S 3 glasses. The intensity dependence of the luminescence on glass composition was consistent with Raman spectra of these glasses. Remarkable differences were found in the upconversion luminescence spectra in comparison with those of Er 3+ -doped halide glasses.

The screen printed CdS/CdTe hetero-junctions formed on the (0001), (1120), (1010) surfaces of CdS single crystals have been studied by an X-ray double crystal spectrometer, electron diffraction, transmission electron microscopy (TEM), and EBIC. For CdS/CdTe formed on the CdS (0001) structure, the epitaxiality of the CdTe layer formed on (0001) of CdS was better than that formed on the other surfaces. The diffusion length of minority carriers formed on the single crystal CdS was found to be larger than that of sintered CdS/CdTe junction prepared by the screen printing method especially for the junctions grown on the (0001) plane of CdS.

In the course of search for new types of oxide ion conductors, we found a perovskite oxide having a large amount of oxygen vacancy in disordered state. Sr 2 ScAlO 5 is the basic composition. The phase obtained at more than 1500°C shows a perfect cubic perovskite structure indicating that the oxygen vacancies are disordered in this phase. The oxide ion conductivity was 10 −4 S cm −1 at 1000°C. To improve the conductivity, the substitution of various elements were tried and finally, Sr 1.8 Ba 0.2 Sc 1.2 Al 0.8 O 4.9 was found to show the conductivity of 10 −2 S cm −1 at 1000°C. The ionic conductivities in this system depended on the unit cell volume and vacancy concentration. The larger cell volume and higher amount of vacancy brought the higher conductivity.

In this study, we tried to continuously measure muscle oxygen consumption (m-VO2) by near infrared spectroscopy (NIRS) without arterial occlusions. We used an intermittent isometric exercise at high intensity, which elicits a spontaneous occlusion of the blood flow to the muscle due to an increase in intramuscular pressure. Changes in muscle oxygenation and phosphocreatine (PCr) concentration were monitored in 5 subjects during an intermittent isometric exercise (5 sec. contraction/5 sec. relaxation) at 50% of maximum voluntary contraction for 3 minutes. The rate of deoxygenation was measured from the 2nd sec. to the 3rd sec. of each muscle contraction. The rate of deoxygenation at the onset of exercise followed an exponential time course with a time constant of 42.0 ± 12.5 sec. (mean±SD). This value agreed with the time constant of the decrease in PCr (48.2 ± 10.2 sec.). This result suggests that m-VO2 was successfully monitored with a time resolution of 10 sec. by NIRS during exercise without arterial occlusion.

We demonstrate a new approach to realize the graded grating, which is effective to improve the modulation characteristics of DFB laser diodes (LDs) for analog optical transmission, by using selective-area-growth (SAG) technique. Ideal parabolic thickness profile and the thickness enhancement ratio as high as 4.6 in the grating layer have been realized by optimizing the mask shape using the simulation technique for SAG. We have also successfully realized the high light-current linearity in 1.3 /spl mu/m DFB-LDs with graded grating for the first time. It has been shown that the LDs have excellent distortion characteristics.

We have fabricated a distributed-feedback laser diode (DFB-LD) with monolithically integrated electroabsorption modulator (EAM), which has small chirp characteristics (effective /spl alpha/ parameter =0.2). 2.5 Gbps-700 km penalty-free transmission without any intentional pre-biasing or self phase modulation effect is successfully demonstrated using the EAM-LD.

Beryllium (Be) has been investigated as p-type dopant for InGaAs layers grown using bismethylcyclopentadienyl-beryllium ((MeCp)/sub 2/Be) by low-pressure metalorganic chemical vapor deposition. It is found that hole concentration is in proportion to the (MeCp)/sub 2/Be flow rate, which results in excellent doping controllability. Moreover, the doping efficiency of (MeCp)/sub 2/Be is one order of magnitude higher than that of diethylzinc (DEZn). InGaAs increases with increasing growth temperature in the temperature range from 570 to 625/spl deg/C. Heavily Be-doped InGaAs layers with specular surface morphology have been attained with a hole concentration in excess of 10/sup 19/ cm/sup -3/ by optimization of growth condition. (MeCp)/sub 2/Be is promising precursor as p-type dopant source for optoelectronic devices.

The purpose of this study was to quantify muscle deoxygenation in human skeletal muscles using near infrared time-resolved spectroscopy (NIRTRS) and compare NIRTRS indicators and blood saturation. The forearm muscles of five healthy males (aged 27-32 yrs.) were monitored for changes in hemoglobin saturation (SO2) during 12 min of arterial occlusion and recovery. SO2 was determined by measuring the temporal profile of photon diffusion at 780 and 830 nm using NIRTRS, and was defined as SO2-TRS. Venous blood samples were also obtained for measurements of SvO2, and PvO2. Interstitial PO2(PintO2) was monitored by placing an O2 electrode directly into the muscle tissue. Upon the initiation of occlusion, all parameters fell progressively until reaching a plateau in the latter half of occlusion. It was observed at the end of occlusion that SO2-TRS (24.1 +/- 5.6%) agreed with SvO2 (26.2 +/- 6.4) and that PintO2 (14.7 +/- 1.0 Torr) agreed with PvO2 (17.3 +/- 2.2 Torr). The resting O2 store (oxygenated hemoglobin) and O2 consumption rate were 290 microM and 0.82 microM s-1, respectively, values which reasonably agree with the reported results. These results indicate that there was no O2 gradient between vessels and interstisium at the end of occlusion.

Glasses containing Er3+ ions of 0.3 to 7 cation mol percent were prepared in the system of Ga2S3-GeS2-LaS3. Frequency upconversion spectra of Er3+ in the glasses were measured under the excitation at 800 nm and 980 nm. Green emissions at 533 nm (2H11/2yields4I15/2) and 552 nm (4S3/2yields4I15/2), and red emission at 665 nm (4F9/2yields4I15/2) were observed.In addition to these emission bands, 497 nm emission assigned to the 4F7/2yields4I15/2 transition was observed. The spectral properties are analyzed from the view points of low phonon energy property and high refractive index.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The purpose of this study was to measure O2 consumption of nonexercising skeletal muscles (VO2nonex) at rest and after aerobic exercise and to investigate the stimulant factors of O2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31P-magnetic resonance spectroscopy during a 15 min arterial occlusion. In experiment 2, the VO2nonex of the finger flexor muscles was measured using near infrared continuous wave spectroscopy at rest, immediate postexercise, and 3, 5, 10, 15, and 20 min following a cycling exercise at a workload corresponding to 50% of peak pulmonary O2 uptake for 20 min. We also monitored deep tissue temperature in the VO2nonex measurement area and determined catecholamines and lactate concentrations in the blood at rest and immediate postexercise. VO2nonex at rest was 1.1 +/- 0.1 microM O2/S (mean +/- standard error) and VO2nonex after exercise increased 59.6 +/- 7.2% (p < 0.001) from the resting values. There were significant correlations between the increase in VO2nonex and the increase in epinephrine concentration (p < 0.01), and between the increase in VO2nonex and the increase in lactate concentration (p < 0.05). These results suggest that epinephrine and lactate concentrations are important VO2nonex stimulant factors.