scholarly journals OSMOTIC PROPERTIES OF THE EGG CELLS OF THE OYSTER (OSTREA VIRGINICA)

1941 ◽  
Vol 25 (2) ◽  
pp. 215-227 ◽  
Author(s):  
Balduin Lucké ◽  
R. A. Ricca
Keyword(s):  
Cell Surface ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Diffraction Method ◽  
Egg Cell ◽  
Concentration Difference ◽  
Wide Range ◽  
The Difference ◽  
Inactive Cell ◽  
Osmotic Properties

Investigations of the osmotic properties of oyster eggs by a diffraction method for measuring volumes have led to the following conclusions: 1. The product of cell volume and osmotic pressure is approximately constant, if allowance is made for osmotically inactive cell contents (law of Boyle-van't Hoff). The space occupied by osmotically inactive averages 44 per cent of cell volume. 2. Volume changes over a wide range of pressures are reversible, indicating that the semipermeability of the cell during such changes remains intact. 3. The kinetics of endosmosis and of exosmosis are described by the equation, See PDF for Equation, where dV is rate of volume change; S, surface area of cell, (P-Pe), the difference in osmotic pressure between cell interior and medium, and K, the permeability of the cell to water. 4. Permeability to water during endosmosis is 0.6µ3 of water per minute, per square micron of cell surface, per atmosphere of pressure. The value of permeability for exosmosis is closely the same; in this respect the egg cell of the oyster appears to be a more perfect osmometer than the other marine cells which have been studied. Permeability to water computed by the equation given above is in good agreement with computations by the entirely different method devised by Jacobs. 5. Permeability to diethylene glycol averages 27.2, and to glycerol 20.7. These values express the number of mols x 10–15 which enter per minute through each square micron of cell surface at a concentration difference of 1 mol per liter and a temperature of 22.5°C. 6. Values for permeability to water and to the solutes tested are considerably higher for the oyster egg than for other forms of marine eggs previously examined. 7. The oyster egg because of its high degree of permeability is a natural osmometer particularly suitable for the study of the less readily penetrating solutes.

scholarly journals THE OSMOTIC PROPERTIES OF LIVING CELLS (EGGS OF ARBACIA PUNCTULATA)

1931 ◽  
Vol 14 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Morton McCutcheon ◽  
Balduin Lucké ◽  
H. Keffer Hartline
Keyword(s):  
Surface Tension ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Sea Water ◽  
Living Cells ◽  
Arbacia Punctulata ◽  
Wide Range ◽  
Inactive Cell ◽  
Osmotic Properties

We have attempted to answer the question: How nearly ideal, as an osmometer, is the unfertilized Arbacia egg? The following conclusion have been reached: 1. Volumes can be measured accurately over a wide range of pressures since the cell is in general spherical and does not suffer deformation from its own weight or other factors. 2. The product of volume and pressure is approximately constant, if allowance be made for osmotically inactive cell contents. It is computed that from 7 to 14 per cent of cell volume is occupied by osmotically inactive material. 3. Evidence is presented that no appreciable escape of cell contents occurs while the cell is in hypotonic sea water; that, therefore, the semipermeability of the membrane is approximately perfect, so long as injury to the cell is avoided. 4. In comparison with osmotic pressure the influence of other forces, such as elasticity or surface tension, on cell volume must in these experiments be slight.

scholarly journals STUDIES ON OSMOTIC EQUILIBRIUM AND ON THE KINETICS OF OSMOSIS IN LIVING CELLS BY A DIFFRACTION METHOD

1935 ◽  
Vol 19 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Balduin Lucké ◽  
Martin G. Larrabee ◽  
H. Keffer Hartline
Keyword(s):  
Cell Surface ◽  
Osmotic Pressure ◽  
Diffraction Pattern ◽  
Monochromatic Light ◽  
Diffraction Method ◽  
Living Cells ◽  
Individual Variability ◽  
Concentration Difference ◽  
Osmotic Equilibrium ◽  
Kinetics Of

1. Osmotic equilibrium and kinetics of osmosis of living cells (unfertilized eggs of Arbacia punctulata) have been studied by a diffraction method. This method consists of illuminating a suspension of cells by parallel monochromatic light and measuring, by means of telescope and scale, the angular dimensions of the resulting diffraction pattern from which the average volume of the cells may be computed. The method is far less laborious and possesses several advantages over direct measurement of individual cells. The average size of a large number of cells is obtained from a single measurement of the diffraction pattern and thus individual variability is averaged out. The observations can be made at intervals of a few seconds, permitting changes in volume to be followed satisfactorily. During the measurements the cells are in suspension and are constantly stirred. 2. Volumes of cells in equilibrium with solutions of different osmotic pressure have been determined. In agreement with our previous experiments, based upon direct microscope measurements, we have confirmed the applicability of the law of Boyle-van't Hoff to these cells; that is to say, the product of volume and pressure has been found to be approximately constant if allowance be made for the volume of osmotically inactive material of the cell contents. The volume of osmotically inactive material was found to be, on the average, 12 per cent of the initial cell volume; in eggs from different animals this value ranged from 6 to 20 per cent. 3. Permeability to water of the Arbacia egg has been found to average, at 22°C., 0.106 cubic micra of water per square micron of cell surface, per minute, per atmosphere of difference in osmotic pressure. 4. Permeability to ethylene glycol has been found to average, at 24°C., 4.0 x 10–15 mols, per square micron of cell surface, per minute, for a concentration difference of 1 mol per liter. This is in agreement with the values reported by Stewart and Jacobs.

Hydraulic Resistance of Plants. II. Effects of Rooting Medium, and Time of Day, in Barley and Lupin

1984 ◽  
Vol 11 (5) ◽  
pp. 341 ◽  
Author(s):  
JB Passioura ◽  
R Munns
Keyword(s):  
Osmotic Pressure ◽  
Hydraulic Resistance ◽  
External Solution ◽  
Time Of Day ◽  
Pressure Chamber ◽  
Sand Soil ◽  
Rooting Medium ◽  
Wide Range ◽  
Flow Through ◽  
The Difference

Barley and lupin plants were grown in pots designed to fit inside a pressure chamber. The pots contained sand, soil, or nutrient solution. Transpiration rates were varied over a wide range. At a given transpiration rate, Q, the balancing pressure, p, of a plant was determined; p is the pneumatic pressure that must be applied to the roots in the pressure chamber to have a cut in the xylem of the shoot on the verge of bleeding. The relation between p and Q, p(Q), was non-linear and hysteretic for solution- grown plants, but was remarkably linear for plants grown in sand or soil, i.e. the data for a given plant on a given occasion conformed closely to the equation p =po + rQ, where po and r were constants. Even though p(Q) was linear for the plants grown in sand or soil, po was often much larger than Δπ, the difference in osmotic pressure between the external solution and the xylem of the root, so that the apparent hydraulic resistance of the plants, i.e. (p-Δπ)/Q, depended strongly on Q. Furthermore, po changed diurnally and was typically 100-200 kPa higher in the afternoon than in the morning. These results are discussed in relation to the equations that are commonly used to describe water flow through plants. It is postulated that r represents the true hydraulic resistance of the plant, which is independent of Q in the plants grown in soil or sand but may vary diurnally, and that the discrepancy between po and Δπ represents either an additional and hitherto unrecognized difference in osmotic pressure across the membranes of the root that intercept the transpiration stream, or a pressure required to open valves through which the water has to pass, with the valves possibly being located in the plasmodesmata.

scholarly journals Osmoregulation in some palaemonid prawns

1941 ◽  
Vol 25 (2) ◽  
pp. 317-359 ◽  
Author(s):  
N. Kesava Panikkar
Keyword(s):  
Steady State ◽  
Osmotic Pressure ◽  
Regulatory Mechanism ◽  
Sea Water ◽  
External Medium ◽  
Wide Range ◽  
Osmotic Behaviour ◽  
The Difference ◽  
Slight Rise ◽  
The Individual

1. The brackish-water prawn Palaemonetes varians and the marine prawns Leander serratus and L. squilla are hypotonic in normal sea water, the blood of these species showing osmotic pressures equivalent to 2·3, 2·8 and 2·6 % NaCl respectively, in an external medium of 3·5 % NaCl.2. Palaemonetes varians is isotonic in water of about 2·0 % NaCl and the species is practically homoiosmotic, the difference in its osmotic pressure over a range of 5·0 % NaCl in the external medium being only 0·8–1·0 %. The species has a very wide range of tolerance from water that is nearly fresh to concentrated sea water equivalent to 5·2 % NaCl.3. Leander serratus is much less homoiosmotic than Palaemonetes, and has a limited tolerance to dilution and concentration of the environment. Homoiosmoticity is maintained up to a dilution of 2·5 % in the external medium when isotonicity is reached; but in lower dilutions there is a steady decline in osmotic pressure and the regulatory mechanism evidently breaks down.4. The osmotic behaviour of Leander squilla is very similar to that of L. serratus, but the homoiosmotic behaviour is more marked and it has greater tolerance to dilution of the environment.5. When Leander and Palaemonetes are transferred to very dilute sea water, the internal osmotic pressure falls gradually for about 14–24 hr., varying according to the size of the individual. After the lowest value has been registered there is a slight rise, and a steady state is thereafter maintained.6. Studies on the changes of weight of prawns when transferred to diluted media indicate that the integument (gills) is permeable to water and that, at least in Leander serratus, the amount of water entering is mainly responsible for the dilution of the blood. There is a similar fall in weight when prawns are transferred to concentrated media, due to loss of water.

The Theory of Osmosis

2003 ◽  
Author(s):  
Larry D. Howlett
Keyword(s):  
Osmotic Pressure ◽  
Atmospheric Pressure ◽  
Traditional Theory ◽  
Theoretical Determination ◽  
Concentration Difference ◽  
Capillary Action ◽  
The Difference ◽  
Basic Equations ◽  
Thermodynamic Derivation

A fresh view for explaining the process of osmosis and the phenomenon of osmotic pressure is presented. The process of osmosis was identified and modeled more than 100 years ago. Others have unsuccessfully challenged the original model developed by J.H. van’t Hoff. We revisit the basic equations and assumptions used in the thermodynamic derivation of the osmosis model. And, we propose a small but significantly different view of the traditional theory of osmosis. From this new view of osmosis and the osmosis experiment, we conclude that osmosis occurs at atmospheric pressure. In cellular membranes, flow from the solvent to the solution is related to the vapor pressure difference determined from the concentration difference with Raoult’s law. Furthermore, we suggest that osmotic pressure as determined from the osmosis experiment is related to both the solution properties and the membrane characteristics. We suggest that the difference between experimental and theoretical determination of osmotic pressure can be attributed to capillary action that may occur in some man made membranes.

Immunogold and immunoblot studies on a cell surface protein found in primary mesenchyme cells and in the cortical secretory vesicles of the sea urchin egg

1987 ◽  
Vol 45 ◽  
pp. 832-833
Author(s):  
G.L. Decker ◽  
M.C. Valdizan
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Surface Protein ◽  
Egg Cell ◽  
Secretory Vesicles ◽  
Cell Surface Protein ◽  
Surface Complexes ◽  
Mesenchyme Cells ◽  
Lowicryl K4m ◽  
Primary Mesenchyme Cells

A monoclonal antibody designated MAb 1223 has been used to show that primary mesenchyme cells of the sea urchin embryo express a 130-kDa cell surface protein that may be directly involved in Ca2+ uptake required for growth of skeletal spicules. Other studies from this laboratory have shown that the 1223 antigen, although in relatively low abundance, is also expressed on the cell surfaces of unfertilized eggs and on the majority of blastomeres formed prior to differentiation of the primary mesenchyme cells.We have studied the distribution of 1223 antigen in S. purpuratus eggs and embryos and in isolated egg cell surface complexes that contain the cortical secretory vesicles. Specimens were fixed in 1.0% paraformaldehyde and 1.0% glutaraldehyde and embedded in Lowicryl K4M as previously reported. Colloidal gold (8nm diameter) was prepared by the method of Mulpfordt.

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

Generalized Heterodyne Configurations for Photo-induced Force Microscopy

2019 ◽  
Author(s):  
Le Wang ◽  
Devon Jakob ◽  
Haomin Wang ◽  
Alexis Apostolos ◽  
Marcos M. Pires ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Repetition Rate ◽  
Modulation Frequency ◽  
High Harmonic ◽  
Chemical Imaging ◽  
Heterodyne Detection ◽  
Force Microscopy ◽  
Wide Range ◽  
The Difference ◽  
Afm Cantilever

<div>Infrared chemical microscopy through mechanical probing of light-matter interactions by atomic force microscopy (AFM) bypasses the diffraction limit. One increasingly popular technique is photo-induced force microscopy (PiFM), which utilizes the mechanical heterodyne signal detection between cantilever mechanical resonant oscillations and the photo induced force from light-matter interaction. So far, photo induced force microscopy has been operated in only one heterodyne configuration. In this article, we generalize heterodyne configurations of photoinduced force microscopy by introducing two new schemes: harmonic heterodyne detection and sequential heterodyne detection. In harmonic heterodyne detection, the laser repetition rate matches integer fractions of the difference between the two mechanical resonant modes of the AFM cantilever. The high harmonic of the beating from the photothermal expansion mixes with the AFM cantilever oscillation to provide PiFM signal. In sequential heterodyne detection, the combination of the repetition rate of laser pulses and polarization modulation frequency matches the difference between two AFM mechanical modes, leading to detectable PiFM signals. These two generalized heterodyne configurations for photo induced force microscopy deliver new avenues for chemical imaging and broadband spectroscopy at ~10 nm spatial resolution. They are suitable for a wide range of heterogeneous materials across various disciplines: from structured polymer film, polaritonic boron nitride materials, to isolated bacterial peptidoglycan cell walls. The generalized heterodyne configurations introduce flexibility for the implementation of PiFM and related tapping mode AFM-IR, and provide possibilities for additional modulation channel in PiFM for targeted signal extraction with nanoscale spatial resolution.</div>

Capillary pressure, osmotic pressure and bubble contact areas in foams

Soft Matter ◽  
2021 ◽  
Author(s):  
Reinhard Höhler ◽  
Jordan Seknagi ◽  
Andrew Kraynik
Keyword(s):  
Osmotic Pressure ◽  
Capillary Pressure ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Average Pressure ◽  
Contact Areas ◽  
The Difference

The capillary pressure of foams and emulsions is the difference between the average pressure in the dispersed phase and the pressure in the continuous phase.

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