The influence of the nucleus on sequential determination in frog ectoderm following induction by lithium ion

Development ◽  
1969 ◽  
Vol 21 (3) ◽  
pp. 383-390
Author(s):  
Krystyna D. Ansevin
Keyword(s):  
Cell Nucleus ◽  
Cellular Differentiation ◽  
Intrinsic Factor ◽  
Lithium Ion ◽  
Morphological Differentiation ◽  
Competent Cell ◽  
Cell Cytoplasm ◽  
Sequential Determination ◽  
Complex Sequence ◽  
Short Period

It appears certain that the process of cellular differentiation is an outcome of interactions between the cell nucleus and cell cytoplasm. Differentiation of embryonic amphibian ectoderm involves two fairly distinct phases: during the first short period an inductor (or some intrinsic factor, if an inductor is absent) determines the course of future differentiation in a multipotential cell; during the second, longer interval of time presumably a complex sequence of reactions leads to physiological and morphological differentiation. Little is known about the nature of reactions which take place during the first phase when the cells become developmentally determined by the inductor. It appears that the first step in translation of the inductive instruction in the competent cell is accomplished during the first 2 or 3 h following the treatment with the inductor (Ansevin, 1966). The step is not actinomycin-sensitive (Ansevin, 1965), as was shown by cells that completely recovered after actinomycin treatment (in conditions when it was unlikely that they could have failed to take up some inhibitor).

Avian Haemoproteidae. I. Description of Haemoproteus fallisi n. sp. and a review of the haemoproteids of the family Turdidae

1972 ◽  
Vol 50 (10) ◽  
pp. 1269-1275 ◽  
Author(s):  
Gordon F. Bennett ◽  
A. G. Campbell
Keyword(s):  
Host Cell ◽  
Cell Nucleus ◽  
Geographical Range ◽  
Nomen Nudum ◽  
Turdus Migratorius ◽  
Cell Cytoplasm ◽  
American Robin ◽  
Host Cell Cytoplasm ◽  
The Family ◽  
Host Cell Nucleus

Haemoproteus fallisi n. sp. is described from the American robin. Turdus migratorius L. Other hosts and geographical range are cited and a summary of haemoproteid infections in the Turdidae is included. H. fallisi is compared with other haemoproteids described from the Turdidae, H. moruony de Mello and Braz de Sa is synonomized with H. fringillae and H. orizivora. H. geocichla Cleland and Johnson is considered to be a nomen nudum. Haemoproteus danilewskyi, also recorded from the Turdidae, is distinguished from H. fallisi by its larger size and by the fact that it surrounds the host cell nucleus and occupies nearly all of the host cell cytoplasm.

scholarly journals Three-Dimensional Thermal Simulations of 18650 Lithium-Ion Batteries Cooled by Different Schemes under High Rate Discharging and External Shorting Conditions

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6986
Author(s):  
Yang Li ◽  
Zhifu Zhou ◽  
Jian Zhao ◽  
Liang Hao ◽  
Minli Bai ◽  
...  
Keyword(s):  
Lithium Ion Battery ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Battery Pack ◽  
High Rate ◽  
Air Cooling ◽  
Two Phase ◽  
Battery Cell ◽  
Short Period ◽  
Thermal Simulations

In this work, three-dimensional thermal simulations of single 18650 lithium-ion battery cell and 75 V lithium-ion battery pack composed of 21 18650 battery cells are performed based on a multi-scale multi-domain (MSMD) battery modeling approach. Different cooling approaches’ effects on 18650 lithium-ion battery and battery pack thermal management under fast discharging and external shorting conditions are investigated and compared. It is found that for the natural convection, forced air cooling, and/or mini-channel liquid cooling approaches, the temperature of battery cell easily exceeds 40 °C under 3C rate discharging condition. While under external shorting condition, the temperature of cell rises sharply and reaches the 80 °C in a short period of time, which can trigger thermal runaway and may even lead to catastrophic battery fire. On the other hand, when the cooling method is single-phase direct cooling with FC-72 as coolant or two-phase immersed cooling by HFE-7000, the cell temperature is effectively limited to a tolerable level under both high C rate discharging and external shorting conditions. In addition, two-phase immersed cooling scheme is found to lead to better temperature uniformity according to the 75 V battery pack simulations.

scholarly journals Sequential determination of 99Tc and 126Sn in radioactive concentrate

2017 ◽  
Vol 10 (1) ◽  
pp. 61-64 ◽  
Author(s):  
Veronika Silliková ◽  
Silvia Dulanská
Keyword(s):  
Anion Exchange ◽  
Exchange Resin ◽  
Scintillation Counter ◽  
Cation Exchange Resin ◽  
Sequential Method ◽  
Time Activity ◽  
Sequential Determination ◽  
Short Period ◽  
Time Required

Abstract This paper describes a new sequential method using anion exchange resin, which is commercially available from Eichrom Technologies, Inc., for the determination of 99Tc and 126Sn in nuclear waste samples. For the determination of non-actinide radionuclides in radioactive wastes, several methods have been recently introduced. This method is suitable for the separation of radionuclides 99Tc and 126Sn from acidic solutions. Samples after digestion were directly loaded in 2 mol·dm-3 HCl acid on a cation exchange resin and then on an anion exchange. They were eluted with HNO3. After elution, the eluted fractions were measured either by gamma spectrometry on an HPGe detector or liquid scintillation counter with high chemical recoveries for a short period of time. Activity concentrations of 126Sn were below minimum detectable activity (MDA) for each experiment. A new radioanalytical method for the sequential determination of 99Tc and 126Sn in radioactive concentrates has been developed and successfully applied. The main advantage of the method was the time required for the separation of radionuclides, which was only five hours, and single column separation for the determination of these radionuclides, which makes the method very effective and cheap.

scholarly journals STUDIES ON THE SITE OF SYNTHESIS OF SEVERAL SOLUBLE ENZYMES OF THE CELL NUCLEUS

1971 ◽  
Vol 50 (1) ◽  
pp. 1-9 ◽  
Author(s):  
LeRoy Kuehl ◽  
Earl N. Sumsion
Keyword(s):  
Cell Nucleus ◽  
Gel Electrophoresis ◽  
Lactic Dehydrogenase ◽  
Nuclear Proteins ◽  
Enzyme Treatment ◽  
Cytoplasmic Enzyme ◽  
Cytoplasmic Proteins ◽  
Short Period ◽  
Specific Activities ◽  
Soluble Enzymes

Rats were given radioactive L-leucine intravenously. At various times after injection, the livers were removed and separated into nuclear and cytoplasmic fractions by a nonaqueous technique. Glyceraldehyde-3-phosphate dehydrogenase, aldolase, and lactic dehydrogenase were isolated from each cell fraction by antibody precipitation followed by gel electrophoresis, and the specific radioactivities of the isolated enzymes were determined. In all three cases, the onset of labeling and the rate of incorporation were the same for the nuclear enzyme as for the corresponding enzyme from the cytoplasm. If we assume that equilibration of the enzymes between the cytoplasmic and nuclear pools occurs slowly relative to the labeling times employed, we may conclude that the labeled nuclear enzymes either were synthesized in the nucleus or moved into the nucleus from a cytoplasmic site of synthesis without first passing into the cytoplasmic pool of enzyme. Treatment with puromycin, an antibiotic which depresses incorporation into cytoplasmic proteins to a greater extent than into nuclear proteins, led to a situation in which the specific activities of the nuclear enzymes were several times as high as those of the corresponding cytoplasmic enzymes following a short period of incorporation. These data substantiate the assumption that equilibration between the cytoplasmic and nuclear enzyme pools occurs slowly and provide further evidence that the labeled nuclear enzymes do not arise from the cytoplasmic enzyme pool.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

the effects of resonance with Jupiter in the system of short-period comets

1974 ◽  
Vol 22 ◽  
pp. 193-203
Author(s):  
L̆ubor Kresák
Keyword(s):  
Structural Effects ◽  
Order Resonance ◽  
Mean Motion ◽  
Short Period ◽  
The Mean ◽  
Compound Effect ◽  
Low Order

AbstractStructural effects of the resonance with the mean motion of Jupiter on the system of short-period comets are discussed. The distribution of mean motions, determined from sets of consecutive perihelion passages of all known periodic comets, reveals a number of gaps associated with low-order resonance; most pronounced are those corresponding to the simplest commensurabilities of 5/2, 2/1, 5/3, 3/2, 1/1 and 1/2. The formation of the gaps is explained by a compound effect of five possible types of behaviour of the comets set into an approximate resonance, ranging from quick passages through the gap to temporary librations avoiding closer approaches to Jupiter. In addition to the comets of almost asteroidal appearance, librating with small amplitudes around the lower resonance ratios (Marsden, 1970b), there is an interesting group of faint diffuse comets librating in characteristic periods of about 200 years, with large amplitudes of about±8% in μ and almost±180° in σ, around the 2/1 resonance gap. This transient type of motion appears to be nearly as frequent as a circulating motion with period of revolution of less than one half that of Jupiter. The temporary members of this group are characteristic not only by their appearance but also by rather peculiar discovery conditions.

Models of comets with strongly variable nongravitational effects

1999 ◽  
Vol 173 ◽  
pp. 381-387
Author(s):  
M. Królikowska ◽  
G. Sitarski ◽  
S. Szutowicz
Keyword(s):  
Cometary Nucleus ◽  
Spin Axis ◽  
Reactive Force ◽  
Orbital Elements ◽  
Cometary Nuclei ◽  
Short Period ◽  
Basic Parameters ◽  
Polar Radius ◽  
Cometary Activity ◽  
Nongravitational Effects

AbstractThe nongravitational motion of five “erratic” short-period comets is studied on the basis of published astrometric observations. We present the precession models which successfully link all the observed apparitions of the comets: 21P/Giacobini-Zinner, 31P/Schwassmann-Wachmann 2, 32P/Comas Solá, 37P/Forbes, and 43P/Wolf-Harrington. We used the Sekanina's forced precession model of the rotating cometary nucleus to include the nongravitational terms into equations of the comet's motion. Values of six basic parameters (four connected with the rotating comet nucleus and two describing the precession of spin-axis of the nucleus) have been determined along the orbital elements from positional observations of the comets. The solutions were derived with additional assumptions which introduce instantaneous changes of modulus of reactive force,Aand of maximum of cometary activity with respect to perihelion time. The present precession models impose some contraints on sizes and rotational periods of cometary nuclei. According to our solutions the nucleus of 21P/Giacobini-Zinner with oblateness along the spin-axis of about 0.32 (equatorial to polar radius of 1.46) is the most oblate among five investigated comets.

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

Sign in / Sign up

Export Citation Format

Share Document