Estimation of total body fat from potassium-40 content

A brief review is given of the development of methods for the determination of total body potassium by whole-body scintillation counting and of studies to establish the utility of body potassium as a measure of gross body composition including fat.     

Estimation of total body fat from potassium-40 content

On the assumption that the potassium content of the lean body mass is constant, it should be possible to estimate fat content in living man from a measurement of potassium-40 activity in the whole-body scintillation counter. A series of such measurements on children and young adults shows good correlations with skin-fold thickness and weight/height ratio as indices of fatness.     

Initial solar irradiance determinations from nimbus 7 cavity radiometer measurements

Preliminary results from solar radiation measurements from the earth radiation budget experiment on the Nimbus 7 satellite yield a mean value of 1376.0 watts per square meter for the "solar constant" from 16 November 1978 to 15 May 1979. The observed variability (root-mean-square deviation) is +/- 0.73 watt per square meter (+/- 0.05 percent) for the period.     

Bone density measurements in vivo: improvement of x-ray densitometry

An X-ray bone densitometer has been developed which makes direct tracings of absorption curves on a nearly linear scale. Speed and precision are increased by elimination of x-ray film. Results are reproducible to within 3 percent with a phantom finger, and within 6 percent with human subjects.     

养殖史氏鲟幼鱼的含肉率和鱼肉营养成分分析

测定了史氏鲟Acipenserschrenckii的含肉率和鱼肉营养成分。结果表明,其含肉率为(30 82±1 22)%;4种鲜味氨基酸(天门冬氨酸、谷氨酸、甘氨酸、丙氨酸)总质量分数为5 40%,占氨基酸总量的35 84%;8种人体必需氨基酸总质量分数为6 45%,占氨基酸总量的42 79%。     

Asteroids: surface composition from reflection spectroscopy

Minerals partly composing the surfaces of 14 asteroids are determined by using asteroid reflectance spectra and optical properties of meteorites and other materials. Individual electronic absorption features are identified in the asteroids' spectra. The energies, relative strengths, and shapes of these features are interpreted by using laboratory and theoretical studies. Analysis of the initial 14 asteroid reflectance spectra indicates the presence of the following types of surface materials: six carbonaceous chondrite-like; two stony-iron-like (metal/silicate approximately 1); one iron meteorite-like; one basaltic achondrite-like; and four silicate-metal assemblages (metal/silicate approximately 0.25). These results support the conclusion that the asteroid belt is a source of at least some meteoritic material, and they show a relation between certain asteroids and certain classes of meteoritcs.     

Norepinephrine: release from brain by d-amphetamine in vivo

After injection of H(3)-norepinephrine into the left lateral cerebral ventricle of cats, the lateral and third cerebral ventricles were perfused with an artificial cerebrospinal fluid. Addition of d-amphetamine to the perfusion fluid caused a significant increase in the concentration of H(3)-norepinephrine in the effluent.     

Lunar surface: composition inferred from optical properties

The optical characteristics (intensity, polarization, spectrum, and albedo) of the moon surface are compared with those of rock and meteorite powders. The only materials whose optical properties match those of the lunar surface are basic rocks containing lattice iron but little or no free iron, and then only after irradiation of these rocks by a simulated solar wind. Optical properties of chondritic meteorite powders differ from those of the moon in significant respects. The lunar crust is probably not chondritic, but is similar in composition to terrestrial iron-rich basalts. These results are independent of those from the Surveyor V alpha-scattering experiment and, in addition, provide a basis for extrapolating the Surveyor V analysis to other areas of the moon. The Surveyor V experiment has thus confirmed the value of earth-based optical techniques for the study of the structure and composition of the surfaces of other planets.     

Mercury: surface composition from the reflection spectrum

The reflection spectrum for the integral disk of the planet Mercury was measured and was found to have a constant positive slope from 0.32 to 1.05 micrometers, except for absorption features in the infrared. The reflectivity curve matches closely the curve for the lunar upland and mare regions. Thus, the surface of Mercury is probably covered with a lunar-like soil rich in dark glasses of high iron and titanium content. Pyroxene is probably the dominant mafic mineral.     

Photoacoustic tomography: in vivo imaging from organelles to organs

Photoacoustic tomography (PAT) can create multiscale multicontrast images of living biological structures ranging from organelles to organs. This emerging technology overcomes the high degree of scattering of optical photons in biological tissue by making use of the photoacoustic effect. Light absorption by molecules creates a thermally induced pressure jump that launches ultrasonic waves, which are received by acoustic detectors to form images. Different implementations of PAT allow the spatial resolution to be scaled with the desired imaging depth in tissue while a high depth-to-resolution ratio is maintained. As a rule of thumb, the achievable spatial resolution is on the order of 1/200 of the desired imaging depth, which can reach up to 7 centimeters. PAT provides anatomical, functional, metabolic, molecular, and genetic contrasts of vasculature, hemodynamics, oxygen metabolism, biomarkers, and gene expression. We review the state of the art of PAT for both biological and clinical studies and discuss future prospects.     

Dopamine: release from the brain in vivo by amantadine

After dopamine stores in the caudate nucleus of cats were labeled with [(3)H]dopamine, the ventricular system was perfused with artificial cerebrospinal fluid. The addition of amantadine to the perfusing fluid caused a doserelated increase in the concentrations of [(3)H]dopamine appearing in the perfusion effluent. Subthreshold concentrations of amantadine also enhanced the efflux of [(3)H]dopamine induced by electrical stimulation of the caudate nucleus.     

Jupiter: its infrared spectrum from 16 to 40 micrometers

Spectral measurements of the thermal radiation from Jupiter in the band from 16 to 40 micrometers are analyzed under the assumption that pressure-broadened molecular hydrogen transitions are responsible for the bulk of the infrared opacity over most of this spectral interval. Both the vertical pressure-temperature profile and the molecular hydrogen mixing ratio are determined. The derived value ofthe molecular hydrogen mixing ratio, 0.89 +/- 0.11, is consistent with the solar value of 0.86.     

Argon-40: excess in submarine pillow basalts from kilauea volcano, hawaii

Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.     

DGT法原位测量水体中金属有效态组分及动力学研究

根据不同厚度扩散膜DGT(梯度扩散薄膜)对金属络合易解离态解离能力差异性这一原理,提出了一套计算金属解离动力学及有效态组分方法,并将其应用于水体Zn、Ni、Cu、Fe、Mn、Cd、Pb等金属形态及运移动力学特征差异性计算中。结果表明,研究提出的计算方法,克服了原有方法过拟合的缺点,可以不借助第三方金属形态分析软件一次性计算出金属有效态含量、组分构成及K-1值,且计算结果更好地体现出有效态中络合易解离部分的贡献,计算公式假设参数少,避免了金属价态、有机质组分构成差异性等因素对有效态含量计算的影响。     

Body Temperature of Dermochelys coriacea: Warm Turtle from Cold Water

The deep body temperature of a leatherback turtle, Dermochelys coriacea, taken out of cold water, was 18 degrees C above the water temperature. A large size favoring heat retention from muscular activity is probably responsible for this differential. Cooling rates (k) in water, measured on a second animal, were in the order of 0.001 degrees C per minute per degree of difference between body and ambient temperature.     

North american--pacific relative plate motion in southern california from interferometry

Very long baseline interferometry measurements of baselines crossing the San Andreas fault zone in southern California have provided observational constraints on rates of elastic tectonic strain accumulation. The single site located near this fault (the Jet Propulsion Laboratory site) moves in a direction concordant with the Pacific plate motion vector but at approximately half the net rate relative to North America. This motion agrees approximately in amount with geologically determined displacement rates on the San Andreas fault alone but not with the local strike of the fault. When considered together with complementary geodetic data, these results suggest a complex relation between the short-term accumulation of elastic strain and its permanent accommodation on existing faults.     

Venus lower atmospheric composition: preliminary results from pioneer venus

Initial examination of data from the neutral mass spectrometer on the Pioneer Venus sounder probe indicates that the abundances of argon-36, argon-38, and neon-20 in the Venus atmosphere are much higher than those of the corresponding gases in Earth's atmosphere, although the abundance of radiogenic argon-40 is apparently similar for both planets. The lower atmosphere of Venus includes significant concentrations of various gaseous sulfur compounds. The inlet leak to the mass spectrometer was temporarily blocked by an apparently liquid component of the Venus clouds during passage through the dense cloud layer. Analysis of gases released during the evaporation of the droplets shows the presence of water vapor to some compound or compounds of sulfur.     

Solar constant: constraints on possible variations derived from solar diameter measurements

Climatically significant variation of the solar constant (the energy output of the sun) implies measurable change in the solar radius. The available data limit variations of the solar radius between 1850 and 1937 to about 0.25 arc second; modeling of the sun indicates that the solar constant did not vary by more than 0.3 percent during that time.