Determination of the protoplasmic viscosity of Paramecium by the centrifuge method

PROTOPLASMA ◽  
1927 ◽  
Vol 2 (1) ◽  
pp. 381-382
Keyword(s):  
Centrifuge Method ◽  
Protoplasmic Viscosity

scholarly journals The Protoplasmic Viscosity of Paramecium

1940 ◽  
Vol 17 (3) ◽  
pp. 317-324
Author(s):  
R. H. J. BROWN
Keyword(s):  
Centrifuge Method ◽  
Protoplasmic Viscosity ◽  
Sources Of Error ◽  
Improved Technique

1. An improved technique for measuring the protoplasmic viscosity of certain types of cell is described. 2. It is shown that the viscosity of Paramecium is not greater than 0.5 c.g.s. unit, and that it may be much less. 3. A simplified type of microscope centrifuge has revealed several sources of error in the centrifuge method customarily employed for the determination of protoplasmic viscosity.

scholarly journals Temperature and the Viscosity of Protoplasm

1924 ◽  
Vol 13 (2) ◽  
pp. 331-339 ◽  
Author(s):  
C. F. A. Pantin
Keyword(s):  
Chemical Process ◽  
Plant Cells ◽  
Effect Of Temperature ◽  
Biological Processes ◽  
Nereis Diversicolor ◽  
Centrifuge Method ◽  
Temperature Coefficients ◽  
Protoplasmic Viscosity ◽  
Viscosity Factor ◽  
Viscosity Changes

(1) The effect of temperature on the viscosity of the protoplasm has been determined in the unripe eggs of Nereis diversicolor by the centrifuge method.The viscosity rises as the temperature falls, the rise becoming rapid near 0°C.(2) These changes of viscosity with temperature are similar to those described by Weber (21) in the protoplasm of certain plant cells.(3) Attention is drawn to the fact that the temperature coefficients of biological processes should be corrected for the viscosity of the protoplasm in which they occur.(4) It is shown that the relative changes of protoplasmic viscosity with temperature are probably of the order required to make the temperature coefficients of biological processes constant when corrected for the viscosity factor.(5) The magnitude of the temperature coefficients of biological processes when corrected for viscosity changes is probably of the same order as that of the temperature coefficients of a chemical process when corrected for changes in the viscosity of its medium.

scholarly journals Centrifuge experiments for the determination of the moisture storage and transport properties in the overhygroscopic range

2019 ◽  
Vol 282 ◽  
pp. 02035
Author(s):  
Evy Vereecken ◽  
Staf Roels ◽  
Hans Janssen
Keyword(s):  
Transport Properties ◽  
Simultaneous Determination ◽  
Theoretical Point ◽  
Moisture Retention ◽  
Reliable Determination ◽  
Retention Curve ◽  
Centrifuge Method ◽  
Moisture Permeability ◽  
Moisture Storage

This study explores the potential of a centrifuge experiment for hygric property determination. In this method, a core sample is placed in a tube which is spun at different rotational speeds to create a distribution of moisture contents and capillary pressures. This way, a simultaneous determination of the moisture retention curve and moisture permeability curve is possible. Measurements performed in the petroleum industry and in soil science already showed the technique to be an appropriate substitute for the pressure plate method. In building physics, the potential of the centrifuge method is currently still unexplored. Therefore, in this study, preliminary desorption measurements on brick samples are performed. To infer the moisture retention curve, an approximate data analysis method is applied. This approach is compared to a more sophisticated parameter estimation technique, which is also used to infer the moisture permeability curve. From a theoretical point of view, the centrifuge method allows a simultaneous determination of the moisture storage and transport properties of building materials. In practice, however, experimental inaccuracies make the experimental results unusable for a reliable determination of the moisture transport properties.

Determination of the osmotic pressure of latex dispersions by a thin layer centrifuge method

1986 ◽  
Vol 18 (2-4) ◽  
pp. 283-291 ◽  
Author(s):  
Tibor Gilányi ◽  
Géza Horváth-Szabó ◽  
Ervin Wolfram
Keyword(s):  
Thin Layer ◽  
Osmotic Pressure ◽  
Centrifuge Method ◽  
Latex Dispersions

scholarly journals Comparison of Diatoms Which Were Obtained from The External Surface of The Body and Internal Organs in the Corpses Pulled Out of Water Using Colloidal Silica Gradient Centrifuge Method

2019 ◽  
Vol 24 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Çiler Fulya Erkan ◽  
Gürsel Çetin
Keyword(s):  
Colloidal Silica ◽  
Extraction Methods ◽  
Blood Stream ◽  
The Body ◽  
Acid Digestion ◽  
Internal Organs ◽  
Centrifuge Method ◽  
Nitric Acid Digestion ◽  
Diatom Test

 Objective: Diatom analysis is a valuable tool in forensic science and it is useful in diagnosis of drowning and determination of the drowning site. The basic principal of the “diatom test” in investigation of drowning is based on correlation between diatoms are present in the medium where the possible drowning took place and inhalation of water causes penetration of diatoms into the alveolar system and blood stream and consequently their deposition into brain, kidneys and other organs, like the bone marrow of large bones. There are various extraction methods that are used to isolate diatoms from water and tissues. Nitric acid digestion is a worlwide known method for the extraction of diatoms. In this study, instead of acid digestion method, colloidal silica gradient centrifuge method was used to extraction diatom and the advantages of this technique has been aimed to be discussed. Materials and Methods: Therefore, 30 visceral and body fluid samples that have been obtained from corpses which were removed from the water and brought to the Council of Forencic Medicine to perform autopsy, were examined and diatom were obtained from samples of 19 cases. Moreover, the diatoms that were obtained from the swab samples taken from the outer body surfaces and the diatoms obtained from the visceral organs were compared. Results:  When the diatoms which were obtained from internal organs tissues and body fluids were evaluated numerically, it was seen that the diatoms that were obtained lungs were in high numbers and it was followed by pleural liquid...

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