On the ice, formed under peculiar circumstances, at the bottom of running water

1837 ◽  
Vol 3 ◽  
pp. 330-331
Keyword(s):  
Freezing Point ◽  
Whole Body ◽  
Ground Ice ◽  
Running Water ◽  
Small Crystals ◽  
Great Transparency ◽  
Short Space ◽  
Rapid Current ◽  
Solid Glass ◽  
Natural Channel

The ice, which is frequently observed to collect at the bottom of streams and rivers, differs in appearance from that which is formed at the surface; for, instead of assuming the shape of solid glass like plates, it has more the appearance of aggregated masses of snow, and is composed of small crystals of ice adhering together irregularly, either by their sides or angles. Rivers are sometimes so choked up by accumulations of ground-ice of this description, that they are not only impeded in their course, but also raised considerably above their banks. While in this state, a slight change in the weather will frequently occasion the complete disengagement of this ice from the bottom; so that, in a very short space of time, the river returns into its natural channel; and then, although it may be frozen at the surface, it continues to flow over a perfectly clear bottom. All these phenomena are considered by the author as perfectly explicable on the theory he advances, of different degrees of radiation of heat occurring from the bottom according to variations of circumstances. He conceives that when this radiation takes place from the solid opake materials of the bed of the stream, through the stratum of transparent water, congelation is induced on that portion of fluid, already cooled down to the freezing-point, which is in immediate contact with the radiating body. The circumstances which, by favouring radiation, contribute to this effect, are, principally, great clearness of the sky, and great transparency of the water; the bottom of the river being cooled below the freezing-point sooner than the water which is flowing over it; and the ice, formed at the bottom, remaining attached to it, as long as the heat which is transmitted from below continues to be lost by radiation. The formation of ground-ice is favoured by the intestine motions incident to a rapid current; because the different strata of fluid, which in still water would have arranged themselves, according to their specific gravities, in the order most conducive to the congelation of the surface, being continually mixed together, the whole body of water is cooled more uniformly. The Society then adjourned over the Easter recess to meet again on the 30th instant.

Blood osmolality in vitro: dependence on base addition, buffer value, and temperature

1987 ◽  
Vol 62 (6) ◽  
pp. 2174-2179 ◽  
Author(s):  
N. Maassen ◽  
D. Boning
Keyword(s):  
Freezing Point ◽  
Whole Body ◽  
Co2 Absorption ◽  
Ph Change ◽  
Blood Osmolality ◽  
Respiratory Compensation ◽  
Equilibration Temperature ◽  
Buffer Value ◽  
Osmotic Effects

Blood osmolality (Osm) increases with PCO2 because of CO2 absorption. The influences of NaOH addition, equilibration temperature, and hemoglobin concentration on these respiratory changes of Osm were measured by freezing-point determination in true plasma. Addition of NaOH increases Osm by 2 mosmol X kg H2O-1 X mmol base-1 X l at constant PCO2 due to the osmotic effects of Na+ and produced bicarbonate. Respiratory compensation of the pH change further increases Osm. This contrasts to the respiratory compensation of the osmolar disturbance caused by fixed acid. Raising the equilibration temperature reduces Osm by 0.5 mosmol X kg H2O-1 X degrees C-1 at constant pH mainly caused by a lower absorption coefficient for CO2 and changed pK value for H2CO3. The slope of the linear regression lines between Osm and pH during CO2 equilibration increases with hemoglobin; the value of the quotient delta Osm/delta pH depends directly on the nonbicarbonate buffer value. The use of this quotient for the estimation of the mean nonbicarbonate buffer value of the whole body is suggested. The osmotic effects of therapeutic base infusion should be regarded with caution.

Abstract 171: Plasma Hypoosmolarity After Birth Promotes Closure of the Ductus Arteriosus

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Rika Aoki ◽  
Utako Yokoyama ◽  
Yasuhiro Ichikawa ◽  
Shun Kumagaya ◽  
Shiho Iwasaki ◽  
...  
Keyword(s):  
Cord Blood ◽  
Preterm Infants ◽  
Transient Receptor Potential ◽  
Freezing Point ◽  
Ductus Arteriosus ◽  
Receptor Potential ◽  
Whole Body ◽  
Plasma Osmolarity ◽  
Transient Receptor Potential Melastatin

Background: Changes in environmental conditions after birth, such as increased oxygen tension, are known to regulate the closure of the ductus arteriosus (DA). We previously found that plasma osmolarity was significantly decreased early after birth in rats, and that Transient Receptor Potential Melastatin (TRPM) 3, a hypoosmolarity sensor, was highly expressed in the rat DA compared to the aorta. We assessed the hypothesis that plasma hypoosmolarity regulated tension of the DA via TRPM3. Methods: Fura-2 assay was used to evaluate the change in intracellular calcium [Ca 2+ ] i in vascular smooth muscle cells (SMCs). Tension of vascular rings was measured by a wire myograph system. Rapid whole-body freezing method was used to examine vasoconstriction in rat in vivo . Plasma osmolarity of human preterm infants was analyzed by freezing point depression osmometry. Results: We found that [Ca 2+ ] i was increased by hypoosmolarity (270mOsm/kg) in SMCs isolated from the rat DA (DASMCs) compared to aortic SMCs (31.3% vs. 8.5% of basal 340/390 ratio P <0.01, n=6). When DASMCs were treated with siTRPM3, hypoosmolarity-induced [Ca 2+ ] i elevation was attenuated by 48.7% ( P <0.01, n=6). Hypoosmolarity (270 and 250mOsm/kg) increased the tension of rat DA (17.4% and 29.8% of 120mM of KCl, respectively, P <0.01, n=8). Moreover, a TRPM3 activator pregnenolone sulfate (200μ M) induced contraction of the rat DA (39.4% of KCl P <0.001, n=6). Conversely, when plasma osmolarity was kept higher to 322mOsm/kg by intra-peritoneal injection of 5.4% hypersaline, the DA closure was partially inhibited by 13% compared to 0.9% saline injection in vivo ( P <0.05, n=11). Plasma osmolarity was decreased 2 h after birth in late preterm infants (28-35weeks’ gestation) (3.2±0.8 % reduction of cord blood, P <0.001, n=35), but not in early preterm infants (24-27weeks’ gestation) (1.1±1.3 % reduction of cord blood, NS , n=17). Furthermore, plasma osmolarity of patent DA (PDA) patients recovered to the adult level by the 2nd day of life while it still remained low in non PDA patients. Conclusions: These results suggest that plasma hypoosmolarity after birth promotes DA closure via TRPM3 and that keeping the plasma osmolarity within proper levels during early neonatal period would be important for DA closure.

III. On ground gru, or ice formed, under peculiar circumstances, at the bottom of running water

1841 ◽  
Vol 131 ◽  
pp. 37-39
Keyword(s):  
Royal Society ◽  
Freezing Point ◽  
Dry Land ◽  
Running Water ◽  
Clear Sky ◽  
Lower Temperature ◽  
In The Beginning

In a paper of mine on Ground Gru, or ice formed at the bottom of running water, which was honoured with a place in the Philosophical Transactions, I had inferred, from a great many conditions attending a remarkable occurrence of the phenomenon in the rivers Don and Leochal, in the beginning of January 1835, as well as from its occurring only when the air is at the time quite clear, that it is caused, when the water has gone down in temperature to the freezing point, by the bottom of the water being cooled to a still lower temperature, in the same manner as the surface of the dry land, under a clear sky, is cooled down below the temperature of the air, as first demonstrated by the experiments of Dr. Wells. As the accuracy of the conclusion at which I arrived respecting the question has been controverted, I respectfully request the Royal Society to permit me to present to them brief notices of some recent occurrences of ground gru, in the same rivers to which I formerly referred, the conditions of which seem to me strongly to confirm the accuracy of the views I presented regarding the cause of the phenomenon; and also to answer some of the objections which have been brought against it.

Occurrence and biogeographic significance of Heliaster (Echinodermata: Asteroidea) from the Pliocene of southwest Florida

1988 ◽  
Vol 62 (01) ◽  
pp. 126-132 ◽  
Author(s):  
Douglas S. Jones ◽  
Roger W. Portell
Keyword(s):  
Central American ◽  
Eastern Pacific ◽  
Whole Body ◽  
Marine Fauna ◽  
Western Atlantic ◽  
Southwest Florida ◽  
Extant Species ◽  
Geologic Record ◽  
Central American Isthmus

Whole body asteroid fossils are rare in the geologic record and previously unreported from the Cenozoic of Florida. However, specimens of the extant species,Heliaster microbrachiusXantus, were recently discovered in upper Pliocene deposits. This marks the first reported fossil occurrence of the monogeneric Heliasteridae, a group today confined to the eastern Pacific. This discovery provides further non-molluscan evidence of the close similarities between the Neogene marine fauna of Florida and the modern fauna of the eastern Pacific. The extinction of the heliasters in the western Atlantic is consistent with the pattern of many other marine groups in the region which suffered impoverishment following uplift of the Central American isthmus.

Cerebral Tissue Response in Chronic Electrode Implantation

1977 ◽  
Vol 35 ◽  
pp. 624-625
Author(s):  
R.F. Dodson ◽  
L.W-F Chu ◽  
N. Ishihara
Keyword(s):  
Tissue Response ◽  
Whole Body ◽  
Platinum Electrodes ◽  
Fixed Tissue ◽  
Electrode Implantation ◽  
Surface Areas ◽  
Tissue Changes ◽  
Micron Diameter ◽  
Extent Of Damage ◽  
Electrode Sheath

The extent of damage surrounding an implanted electrode in the cerebral cortex is a question of significant importance with regard to attaining consistency and validity of physiological recordings. In order to determine the extent of such tissue changes, 150 micron diameter platinum electrodes were implanted in the cortex of four adult baboons, and after eight days the animals were sacrificed by whole body perfusion with a 3% glutaraldehyde in 0.1M phosphate fixative.The calvarium was carefully removed and the electrode tracts were readily discernible in the firm, glutaraldehyde fixed tissue.Careful dissection of the zone of the electrode tract resulted in a small block which was further sectioned into tip, mid-tract and surface areas. Ultrastructurally, damage extended from the electrode sheath to the greatest extent of from 0.2 to 3.5 mm.

Intranuclear Crystals in Regenerating Canine Kidneys

1973 ◽  
Vol 31 ◽  
pp. 412-413
Author(s):  
D.G. Osborne ◽  
L.J. McCormack ◽  
M.O. Magnusson ◽  
W.S. Kiser
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Tubular Epithelial Cell ◽  
Tubular Epithelial Cells ◽  
Cell Nuclei ◽  
Crystalline Structures ◽  
Small Crystals ◽  
Membrane Bound

During a project in which regenerative changes were studied in autotransplanted canine kidneys, intranuclear crystals were seen in a small number of tubular epithelial cells. These crystalline structures were seen in the control specimens and also in regenerating specimens; the main differences being in size and number of them. The control specimens showed a few tubular epithelial cell nuclei almost completely occupied by large crystals that were not membrane bound. Subsequent follow-up biopsies of the same kidneys contained similar intranuclear crystals but of a much smaller size. Some of these nuclei contained several small crystals. The small crystals occurred at one week following transplantation and were seen even four weeks following transplantation. As time passed, the small crystals appeared to fuse to form larger crystals.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Neutrophil Myeloperoxidase Destruction by Ultraviolet Irradiation

1988 ◽  
Vol 46 ◽  
pp. 138-139
Author(s):  
J. Hanker ◽  
B. Giammara ◽  
G. Strauss
Keyword(s):  
Uv Radiation ◽  
Myeloid Leukemia ◽  
Stratospheric Ozone ◽  
Psoriasis Patient ◽  
Whole Body ◽  
Human Neutrophils ◽  
Cupric Nitrate ◽  
The Earth ◽  
Routine Handling ◽  
Uvb Phototherapy

Only a fraction of the UV radiation emitted by the sun reaches the earth; most of the UVB (290-320nm) is eliminated by stratospheric ozone. There is increasing concern, however, that man-made chemicals are damaging this ozone layer. Although the effects of UV on DNA or as a carcinogen are widely known, preleukemia and acute myeloid leukemia (AML) have only rarely been reported in psoriasis patients treated with 8-methoxypsoralen and UV (PUVA). It was therefore of interest to study the effects of UV on the myeloperoxidase (MP) activity of human neutrophils. The peroxidase activity of enriched leukocyte preparations on coverslips was shown cytochemically with a diaminobenzidine medium and cupric nitrate intensification.Control samples (Figs. 1,4,5) of human bloods that were not specifically exposed to UV radiation or light except during routine handling were compared with samples which had been exposed in one of several different ways. One preparation (Fig. 2) was from a psoriasis patient who had received whole-body UVB phototherapy repeatedly.

HVEM Cryomicroscopy of Frozen Hydrated PTK1 Cells

1990 ◽  
Vol 48 (1) ◽  
pp. 500-501
Author(s):  
E.T. O’Toole ◽  
G.P. Wray ◽  
J.R. Kremer ◽  
J.R. Mcintosh
Keyword(s):  
Liquid Nitrogen ◽  
Phase Contrast ◽  
Culture Medium ◽  
Low Dose ◽  
Ammonium Acetate ◽  
Freezing Point ◽  
Voltage Electron ◽  
Cold Stage ◽  
Humidity Chamber ◽  
Coated Carbon

Ultrarapid freezing and cryomicroscopy of frozen hydrated material makes it possible to visualize samples that have never been exposed to chemical fixatives, dehydration, or stains. In principle, freezing and cryoimaging methods avoid artifacts associated with chemical fixation and processing and allow one to visualize the specimen in a condition that is close to its native state. Here we describe a way to use a high voltage electron microscope (HVEM) for the cryoimaging of frozen hydrated PTK1 cells.PTK1 cells were cultured on formvar-coated, carbon stabilized gold grids. After three days in culture, the grids were removed from the culture medium and blotted in a humidity chamber at 35° C. In some instances, the grids were rinsed briefly in 0.16 M ammonium acetate buffer (pH 7.2) prior to blotting. After blotting, the grids were transferred to a plunging apparatus and plunged into liquid ethane held directly above its freezing point. The plunging apparatus consists of a vertical slide rail that guides the fall of a mounted pair of forceps that clamp the specimen. The forceps are surrounded by a plexiglass humidity chamber mounted over a dewar of liquid nitrogen containing an ethane chamber. After freezing, the samples were transferred to liquid nitrogen and viewed in a JEOL JEM 1000 equipped with a top entry cold stage designed and built by Mr. George Wray (Univ. Colorado). The samples were routinely exposed to electron doses of 1 e/Å2/sec, and viewed at a temperature of −150° C. A GATAN video system was used to enhance contrast and to estimate the correct amount of underfocus needed to obtain phase contrast at various magnifications. Low dose micrographs were taken using two second exposures of Kodak 4463 film. The state of the solid water in the specimen was determined by diffraction using a 30/μm field limiting aperture and a camera length of 1 meter.

Sign in / Sign up

Export Citation Format

Share Document