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At least 109 records · Page 6Linked to original sources
PubMed1980

Coil planet centrifuge - a new method for measurement of osmotic fragility of erythrocytes and its application in alcohol liver injuries.

The present study was designed to examine the osmotic resistance of erythrocytes measured by a new method-Coil Planet Centrifuge under the glutaraldehyde incubation, and to determine free cholesterol and adenine nucleotide contents of glutaraldehyde-treated erythrocytes compared with that of control erythrocytes. Glutaraldehyde increased the osmotic resistance of erythrocytes. Hemolysis end point of glutaraldehyde-treated erythrocytes shifted to hypo-osmolar side after 2.5 h hours incubation (p less than 0.001). Free cholesterol content of erythrocytes was not changed by the addition of glutaraldehyde, however, ATP content significantly increased when compared with controls (p less than 0.001). Moreover, the osmotic resistance of erythrocytes in 55 patients with alcoholic liver injuries and the relation between the disease were examined by Coil Planet Centrifuge. Hemolysis end point shifted to hypo-osmolar side in the patients, and our results suggest that the increase in osmotic resistance is partly responsible for the increase in the rigidity of erythrocytes. This new method was also helpful in evaluation in the clinical course of alcoholic liver injuries.

Adenosine Triphosphate↗
PubMed1996

The transfer of viable microorganisms between planets.

There is increasing acceptance that catastrophic cosmic impacts have played an important role in shaping the history of terrestrial life. Large asteroid and cometary impacts are also capable of displacing substantial quantities of planetary surface material into space. The discovery of Martian rocks on Earth suggests that viable microorganisms within such ejecta could be exchanged between planets. If this conjecture is correct, it will have profound implications for the origin and evolution of life in the solar system.

Archaea↗
PubMed2005

Hydrothermal simulation experiments as a tool for studies of the origin of life on Earth and other terrestrial planets: a review.

The potential of life's origin in submarine hydrothermal systems has been evaluated by a number of investigators by conducting high temperature-high pressure experiments involving organic compounds. In the majority of these experiments little attention has been paid to the importance of constraining important parameters, such as the pH and the redox state of the system. This is particularly revealed in the apparent difficulties in interpreting experimental data from hydrothermal organic synthesis and stability studies. However, in those cases where common mineral assemblages have been used in an attempt to buffer the pH and redox conditions to geologically and geochemically realistic values, theoretical and experimental data seem to converge. The use of mineral buffer assemblages provides a convenient way by which to constrain the experimental conditions. Studies at high temperatures and pressure in the laboratory have revealed a number of reactions that proceed rapidly in hydrothermal fluids, including the Strecker synthesis of amino acids. In other cases, the verification of postulated abiotic reaction mechanisms has not been possible, at least for large molecules such as large fatty acids and hydrocarbons. This includes the Fischer-Tropsch synthesis reaction. High temperature-high pressure experimental methods have been developed and used successfully for a long time in, for example, mineral solubility studies under hydrothermal conditions. By taking advantage of this experimental experience new and, at times, unexpected directions can be taken in bioorganic geochemistry, one being, for instance, primitive two-dimensional information coding. This article critically reviews some of the organic synthesis and stability experiments that have been conducted under simulated submarine hydrothermal conditions. We also discuss some of the theoretical and practical considerations that apply to hydrothermal laboratory studies of organic molecules related to the origin of life on Earth and probably also to the other terrestrial planets.

Buffers↗
PubMed1996

Origin of the terrestrial planets and the moon.

Our ideas about the origin and evolution of the solar system have advanced significantly as a result of the past 25 years of space exploration. Metal-sulfide-silicate partitioning seems to have been present in the early dust components of the solar nebula, prior to chondrule formation. The inner solar nebula was depleted in volatile elements by early solar activity. The early formation of the gas giant, Jupiter, affected the subsequent development of inner solar system and is responsible for the existence of the asteroid belt, and the small size of Mars. The Earth and the other terrestrial planets accreted in a gas-free environment, mostly from volatile-depleted planetesimals which were already differentiated into metallic cores and silicate mantles. The origin of the Moon by a single massive impact with a body larger than Mars explains the angular momentum, orbital characteristics and unique nature of the Earth-Moon system. The density and chemical differences between the Earth and Moon are accounted for by deriving the Moon from the mantle of the impactor.

Aluminum Silicates↗
PubMed1988

Band structure of the solar system: an objective test of the grouping of planets and satellites.

Alfvén in his early work on the origin of the solar system (1942-1946) noted a pronounced band structure in the gravitational potential distribution of secondary bodies, and suggested this feature to be directly related to the formation process. When the critical velocity phenomenon was later discovered, a close agreement was found between the planet-satellite bands on one hand, and the critical velocity limits of the major compound elements in the interstellar medium on the other, suggesting a specific emplacement mechanism for the dusty plasma which presumably constituted the solar nebula. Since the originally perceived band structure was outlined in a qualitative fashion, an attempt is made here to analyze the distribution by a statistical technique, testing the significance of clustering of the observational data in the bands. The results show that, with proper scaling of the parameters, such a band structure indeed appears, with features closely similar to those originally conceived. Some deviations are indicated by the cluster analysis, however; their significance is discussed in terms of process involved in the formation of the solar system.

Astronomical Phenomena↗
PubMed1978

Planetary protection guidelines for outer planet missions.

Facilities, techniques, and operational procedures used to implement Planetary Protection (PP) requirements for the Viking Project are reviewed in order to better define the COSPAR resolution which proposes that Outer Planet spacecraft be assembled using Viking-like clean room technology. It is concluded that, for such missions, PP requirements can be met by adopting Viking clean room standards, personnel and operation procedures, and by establishing PP as an official entity in project management.

Containment of Biohazards↗
PubMed1999

In search of planets and life around other stars.

The discovery of over a dozen low-mass companions to nearby stars has intensified scientific and public interest in a longer term search for habitable planets like our own. However, the nature of the detected companions, and in particular whether they resemble Jupiter in properties and origin, remains undetermined.

Astronomical Phenomena↗
PubMed2002

Formation of giant planets by fragmentation of protoplanetary disks.

The evolution of gravitationally unstable protoplanetary gaseous disks has been studied with the use of three-dimensional smoothed particle hydrodynamics simulations with unprecedented resolution. We have considered disks with initial masses and temperature profiles consistent with those inferred for the protosolar nebula and for other protoplanetary disks. We show that long-lasting, self-gravitating protoplanets arise after a few disk orbital periods if cooling is efficient enough to maintain the temperature close to 50 K. The resulting bodies have masses and orbital eccentricities similar to those of detected extrasolar planets.

Computer Simulation↗
PubMed1995

Condensation of methane, ammonia, and water and the inhibition of convection in giant planets.

The condensation of chemical species of high molecular mass such as methane, ammonia, and water can inhibit convection in the hydrogen-helium atmospheres of the giant planets. Convection is inhibited in Uranus and Neptune when methane reaches an abundance of about 15 times the solar value and in Jupiter and Saturn if the abundance of water is more than about five times the solar value. The temperature gradient consequently becomes superadiabatic, which is observed in temperature profiles inferred from radio-occultation measurements. The planetary heat flux is then likely to be transported by another mechanism, possibly radiation in Uranus, or diffusive convection.

Ammonia↗
PubMed1977

Life and the outer planets I. Performance of terrestrial organisms in ammonia-rich systems.

Survival and growth of organisms has been demonstrated at 298 degrees K in NH3 atmospheres, including ammonia-methane mixtures. Included are bacteria such as Clostridium perfringens, Pseudomonas aeruginosa, fungi such as Penicillium notatum and Torula utilis. Although the biological response in onion and other species of Allium is limited to germination, standard metabolic poisons were active even in 15 M aqueous NH3, at 250 degrees K. The most extreme example of compatibility between NH3-rich environments and terrestrial life was the retention of metabolic capabilities by conidia of Penicillium after 6 months at 233 degrees K in a liquid ammonia-glycerol medium. Tritiated thymidine, uridine and amino acids were incorporated by these conidia unless subjected to intense gamma-radiation. Observations spanning the past decade suggest that the analogies between H2O and NH3 as solvent media or -OH and -NH2, as functional groups are probably valid. Chemical-biological evolution similar to early terrestrial evolution could be compatible with chemical conditions presumed to exist on the outer planets and some of their satellites.

Ammonia↗
PubMed1981

Studies on osmotic fragility of red blood cells determined with a coil planet centrifuge for workers occupationally exposed to lead.

In order to clarify the relationship between lead exposure level and osmotic fragility of red blood cells determined by the coil planet centrifuge method, several clinical laboratory examinations were performed on 27 male workers employed in a scrap lead refining factory using as controls 40 male workers employed in railway construction. The examinations included measurement of red blood cell and reticulocyte counts, hematocrit, MCV, blood and urine lead concentrations, urine coproporphyrin, and urine delta-aminolevulinic acid. The results were: 1. Osmotic fragility of red blood cells was lower in lead workers at all three hemolytic points compared with the controls. Significant difference was observed in hemolysis of the maximum point (P less than 0.05). 2. The red blood cell and reticulocyte counts, hematocrit value and MCV of the lead workers were not significantly different from those of the controls. Values for blood and urine lead, coproporphyrin, and delta-aminolevulinic acid of the lead workers were much higher than those of the controls (P less than 0.01). 3. In lead workers, close relationships between the osmotic fragility and these laboratory findings were observed: blood lead, r = -0.572, P less than 0.01; coproporphyrin, r = -0.608, P less than 0.01; delta-aminolevulinic acid, r = -0.559, P less than 0.01; urine lead, r = -0.453, P less than 0.05.

Adult↗
PubMed1978

Hemolytic pattern of erythrocytes in the newborn measured by the coil planet centrifuge system and its relationship to neonatal jaundice.

Dynamic osmotic fragility of erythrocytes in cord blood and its changes during the neonatal period were studied by means of a coil planet centrifuge system. The starting-point for hemolysis in the newborn become similar to that of adult blood after approximately a week, while the shift of the end-point to the adult range required one month or more. The percentage of fragile cord blood cells with a hemolysis starting-point above 110 m osmol and the maximum bilirubin level during neonatal period were examined. A high percentage of fragile cells was associated with high bilirubin levels, and when fragile cells comprised more than 7.0% of the total cord blood erythrocytes, the bilirubin level tended to rise above 15 mg/dl.

Bilirubin↗
PubMed1979

A proposal concerning the origin of life on the planet earth.

The widely accepted Oparin thesis for the origin and early evolution of life seems sufficiently far from the true state of affairs as to be considered incorrect. It is proposed that life on earth actually arose in the planet's atmosphere, however an atmosphere very different from the present one. Because of an extremely warm surface, the early earth may have possessed no liquid surface water, its water being partitioned between a motten crust and a fairly dense atmosphere. Early preliving systems are taken to arise in the droplet phase in such an atmosphere. The early earth, which resembled Venus then and to some extent now, underwent a transition to its present condition largely as a result of the evolution of methanogenic metabolism.

Animals↗
PubMed1981

Erythrocyte osmotic fragility in various liver diseases--application of coil planet centrifuge system.

A change in erythrocyte osmotic fragility was observed on various liver diseases by means of the coil planet centrifuge (CPC) system, and the relationship between changes in it and in serum lipids was studied. According to the CPC classification of hemolytic patterns of L, M, T and R, the frequency of appearance of T and R increased in liver cirrhosis and primary hepatoma. Hemolytic start and end points both changed considerably in primary hepatoma, acute hepatitis and liver cirrhosis. Change of hemolytic end point which shifted to the hypotonic side is more prominent than that of hemolytic start point. The hemolytic end point showed an inverse correlation to serum alkaline phosphatase and LAP, and correlation to pseudocholinesterase and albumin. Among the relations of red cell fragility and lipids of the lipoprotein fractions, free cholesterol and the ratio of free cholesterol to phospholipid in high density lipoprotein were both in remarkable inverse correlation to the hemolytic end point. Free cholesterol in high density lipoprotein was concluded one of the most important determinants of erythrocyte osmotic fragility.

Acute Disease↗
PubMed1992

Counter-current chromatography of lipoproteins with a polymer phase system using the cross-axis synchronous coil planet centrifuge.

Lipoproteins were separated by counter-current chromatography using the type-XLL coil planet centrifuge. The separation was performed with a polymer phase system composed of 16% (w/w) polyethylene glycol 1000 and 12.5% (w/w) dibasic potassium phosphate by eluting the lower phase at a flow-rate of 0.5 ml/min. About 5 ml of the sample solution containing approximately 150 mg of a lipoprotein mixture were loaded. High- and low-density lipoproteins were resolved within 12 h. Each component was detected by gel electrophoresis with oil red staining.

Centrifugation↗
PubMed1993

Studies on a new cross-axis coil planet centrifuge for performing counter-current chromatography. I. Design of the apparatus, retention of the stationary phase, and efficiency in the separation of proteins with polymer phase systems.

An improved model of the cross-axis synchronous flow-through coil planet centrifuge has been designed in light of previous studies. The apparatus has a versatile feature in that both analytical and preparative columns can be accommodated in both off-center and central positions. Each has merit in separations. Retention of stationary phase was examined with various two-phase solvent systems used for the separation of biopolymers. Both analytical and preparative columns showed satisfactory retention of the stationary phase under optimum conditions. The apparatus was evaluated in separation of a set of protein samples using a polyethylene glycol-potassium phosphate biphasic system. In both types of columns all proteins were resolved with partition efficiencies of 260 to 670 theoretical plates. Further studies indicated that the relatively low partition efficiency of proteins is mainly attributed to their high molecular mass or molecular heterogeneity within each species rather than due to the high viscosity of the polymer phase system.

Centrifugation↗
PubMed1993

Studies on new cross-axis coil planet centrifuge for performing counter-current chromatography. III. Speculations on the hydrodynamic mechanism in stationary phase retention.

Retention of the stationary phases of one organic-aqueous solvent system and three aqueous-aqueous polymer solvent systems was investigated on a cross-axis coil planet centrifuge. A graphic statistical treatment of all the data highlighted the prevailing effect of the inward-outward elution mode. A simplified model was proposed and studies on the paths and accelerations of cross-axis devices described in the previous paper provided explanations about the observed hydrodynamic behaviors.

Centrifugation↗