scholarly journals THE SWELLING OF ISOELECTRIC GELATIN IN WATER

1927 ◽  
Vol 10 (6) ◽  
pp. 893-904 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Bulk Modulus ◽  
Osmotic Pressure ◽  
Elastic Strain ◽  
Elastic Force ◽  
Soluble Substance ◽  
Insoluble Material ◽  
Soluble Material ◽  
Initial Process

The swelling of isoelectric gelatin in water has been found to be in agreement with the following assumptions. Gelatin consists of a network of insoluble material containing a solution of a more soluble substance. Water therefore enters owing to the osmotic pressure of the soluble material and thereby puts the network under elastic strain. The process continues until the elastic force is equal to the osmotic pressure. If the temperature is raised or the blocks of gelatin remain swollen over a period of time, the network loses its elasticity and more water enters. In large blocks this secondary swelling overlaps the initial process and so no maximum can be observed. The swelling of small blocks or films of isoelectric gelatin containing from .14 to .4 gm. of dry gelatin per gm. of water is defined by the equation See PDF for Equation in which Ke = the bulk modulus See PDF for Equation. Ve = gm. water per gm. gelatin at equilibrium; Vf = gm. water per gm. gelatin when the gelatin solidified.

scholarly journals THE SWELLING OF ISOELECTRIC GELATIN IN WATER

1927 ◽  
Vol 10 (6) ◽  
pp. 905-926 ◽  
Author(s):  
John H. Northrop ◽  
M. Kunitz
Keyword(s):  
Osmotic Pressure ◽  
Direct Measurement ◽  
Square Root ◽  
A Value ◽  
Insoluble Material ◽  
Higher Temperature ◽  
Pass Through ◽  
Soluble Material ◽  
Volume Equations ◽  
Secondary Type

It has been assumed that gelatin consists of a network of an insoluble material enclosing a solution of a more soluble material. The swelling of gelatin is therefore primarily an osmotic phenomena in that the water tends to diffuse in owing to the osmotic pressure of the soluble material. This osmotic pressure is opposed by the elasticity of the insoluble constituent, and equilibrium results when these two pressures are equal. The rate of the entrance of water should then obey Poiseuille's law, provided the variable terms are expressed as functions of the volume. Equations have been derived in this way which agree quite well with the experimental curves and which predict the proper relation between the size and shape of the block and the rate of swelling. They lead to a value for the rate of flow of water through gelatin which has been checked by direct measurement. The mechanism assumed predicts that at a higher temperature and under conditions such that the water has to pass through collodion before reaching the gelatin, the experiment should follow the same course as that of osmosis discussed previously. This was also found to be the case. The slow secondary increase in swelling is ascribed to fatigue of the elastic properties of the gelatin. The rate of this secondary swelling should therefore be independent of the size of the block, in contrast to the rate of primary swelling which is inversely proportional to the size. It can further be shown that this secondary swelling should be proportional to the square root of the time, and also that with large blocks at higher temperatures the entire swelling should be of this secondary type. These predictions have also been found to be true.

scholarly journals A FRACTION OF TUBERCLE BACILLI POSSESSING PRIMARY TOXICITY

1955 ◽  
Vol 101 (3) ◽  
pp. 291-311 ◽  
Author(s):  
John K. Spitznagel ◽  
René J. Dubos
Keyword(s):  
Single Injection ◽  
Tissue Reaction ◽  
Chemical Characteristics ◽  
Avirulent Strain ◽  
Petrolic Ether ◽  
Fractional Precipitation ◽  
Single Intraperitoneal Injection ◽  
Insoluble Material ◽  
Local Reactions ◽  
Soluble Material

Tubercle bacilli separated from young cultures were thoroughly extracted with monochlorobenzene at temperatures never exceeding 50°C. From the soluble material, a fraction corresponding to approximately 1 per cent of the total bacillary weight was separated by fractional precipitation with petrolic ether at temperatures of 0° or 4°C.—depending upon the strain of bacilli. The monochlorobenzene-soluble-ether-insoluble material (fraction 7) prepared from BCG-P was found to contain 0.14 per cent nitrogen and 0.4 per cent phosphorus. Some of its other chemical characteristics are described. Fraction 7 proved unable to elicit tuberculin allergy in guinea pigs, but injection of 5 µg. of it into the skin produced severe local reactions. In albino mice, a single intraperitoneal injection of 20 µg. caused loss of muscular tone and of weight followed by death within 9 days. The only tissue reaction observed was a slight degree of peritonitis. In mice of the C57 BL strain, a single injection of 40 µg. also caused death in the same time, but with pulmonary hemorrhages—usually massive. Material similar to fraction 7 was obtained from one virulent, two attenuated, and one avirulent strain of mammalian tubercle bacilli (bovine and human). The fractions obtained from the various strains differed somewhat in solubility and toxicity. The more virulent the culture, the more toxic was the fraction obtained from it; but it is possible that this relation was the result of differences in the effectiveness of the extraction procedures, rather than of characteristics inherent to the cultures. Evidence is presented that the toxicity of fraction 7 accounts for much of the primary toxicity of tubercle bacilli.

scholarly journals Technical note: Analytical formulae for the critical supersaturations and droplet diameters of CCN containing insoluble material

2008 ◽  
Vol 8 (7) ◽  
pp. 1985-1988 ◽  
Author(s):  
H. Kokkola ◽  
M. Vesterinen ◽  
T. Anttila ◽  
A. Laaksonen ◽  
K. E. J. Lehtinen
Keyword(s):  
Aerosol Particles ◽  
Technical Note ◽  
Water Soluble ◽  
Cloud Drop ◽  
Insoluble Material ◽  
Kohler Theory ◽  
Analytical Formulae ◽  
Molecular Sizes ◽  
Organic Particles ◽  
Soluble Material

Abstract. In this paper, we consider the cloud drop activation of aerosol particles consisting of water soluble material and an insoluble core. Based on the Köhler theory, we derive analytical equations for the critical diameters and supersaturations of such particles. We demonstrate the use of the equations by comparing the critical supersaturations of particles composed of ammonium sulfate and insoluble substances with those of model organic particles with varying molecular sizes.

scholarly journals THE SWELLING AND OSMOTIC PRESSURE OF GELATIN IN SALT SOLUTIONS

1926 ◽  
Vol 8 (4) ◽  
pp. 317-337 ◽  
Author(s):  
John H. Northrop ◽  
M. Kunitz
Keyword(s):  
Bulk Modulus ◽  
Osmotic Pressure ◽  
Salt Solution ◽  
Modulus Of Elasticity ◽  
Elastic Limit ◽  
Ion Concentration ◽  
Salt Solutions ◽  
Original Volume ◽  
Expected Result ◽  
Do So

1. The swelling and the osmotic pressure of gelatin at pH 4.7 have been measured in the presence of a number of salts. 2. The effect of the salts on the swelling is closely paralleled by the effect on the osmotic pressure, and the bulk modulus of the gelatin particles calculated from these figures is constant up to an increase in volume of about 800 per cent. As soon as any of the salts increase the swelling beyond this point, the bulk. modulus decreases. This is interpreted as showing that the elastic limit has been exceeded. 3. Gelatin swollen in acid returns to its original volume after removal of the acid, while gelatin swollen in salt solution does not do so. This is the expected result if, as stated above, the elastic limit had been exceeded in the salt solution. 4. The modulus of elasticity of gelatin swollen in salt solutions varies in the same way as the bulk modulus calculated from the osmotic pressure and the swelling. 5. The increase in osmotic pressure caused by the salt is reversible on removal of the salt. 6. The observed osmotic pressure is much greater than the osmotic pressure calculated from the Donnan equilibrium except in the case of AlCl3, where the calculated and observed pressures agree quite closely. 7. The increase in swelling in salt solutions is due to an increase in osmotic pressure. This increase is probably due to a change in the osmotic pressure of the gelatin itself rather than to a difference in ion concentration.

Charge renormalization, osmotic pressure, and bulk modulus of colloidal crystals: Theory

1984 ◽  
Vol 80 (11) ◽  
pp. 5776-5781 ◽  
Author(s):  
S. Alexander ◽  
P. M. Chaikin ◽  
P. Grant ◽  
G. J. Morales ◽  
P. Pincus ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Osmotic Pressure ◽  
Colloidal Crystals ◽  
Charge Renormalization

scholarly journals THE FATE OF INJECTED PARTICULATE ANTIGENS IN RELATION TO THE FORMATION OF ANTIBODIES

1946 ◽  
Vol 84 (2) ◽  
pp. 157-165 ◽  
Author(s):  
T. N. Harris ◽  
W. E. Ehrich
Keyword(s):  
Lymph Node ◽  
Active Substance ◽  
Regional Lymph Node ◽  
Lymphatic Tissue ◽  
Soluble Substance ◽  
Antigenic Material ◽  
Soluble Material ◽  
In Cells

Earlier studies have shown that the injection of antigenic material into the pad of the rabbit's foot is followed by the appearance of antibodies in the regional lymph node, in lymph coming from that node, and especially in the lymphocytes present in such efferent lymph. In the present work the fate of particulate antigenic material has been investigated during the period between its injection into the foot of the rabbit and the appearance of antibodies in the regional lymphatic tissue. It has been found that soluble substance of the same immunologic specificity as the antigenic material injected can be identified in extracts of the injected tissue and of the regional lymph node, and in the efferent lymph from that node. The concentration of this soluble material falls off slowly in the injected tissue in the course of the few days following the injection. It falls off quickly in the extract of the lymph node and in the lymph itself, and its disappearance is succeeded by the appearance of antibody. Evidence is presented that the immunologically active substance is derived from the injected antigenic material by a physiologic process, and this process is discussed as the means by which antigens, originally comprised in cells, are made available to the lymphocyte.

scholarly journals Technical Note: Analytical formulae for the critical supersaturations and droplet diameters of CCN containing insoluble material

2007 ◽  
Vol 7 (6) ◽  
pp. 17967-17974
Author(s):  
H. Kokkola ◽  
M. Vesterinen ◽  
T. Anttila ◽  
A. Laaksonen ◽  
K. E. J. Lehtinen
Keyword(s):  
Aerosol Particles ◽  
Technical Note ◽  
Water Soluble ◽  
Cloud Drop ◽  
Insoluble Material ◽  
Kohler Theory ◽  
Analytical Formulae ◽  
Molecular Sizes ◽  
Organic Particles ◽  
Soluble Material

Abstract. In this paper, we consider the cloud drop activation of aerosol particles consisting of water soluble material and an insoluble core. Based on the Köhler theory, we derive analytical equations for the critical diameters and supersaturations of such particles. We demonstrate the use of the equations by comparing the critical supersaturations of particles composed of ammonium sulfate and insoluble substances with those of model organic particles with varying molecular sizes.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

Strain analysis with nanometer resolution using a conventional transmission electron microsopy technique: electron diffraction contrast imaging revisited

1995 ◽  
Vol 53 ◽  
pp. 168-169
Author(s):  
Koenraad G F Janssens ◽  
Omer Van der Biest ◽  
Jan Vanhellemont ◽  
Herman E Maes ◽  
Robert Hull
Keyword(s):  
Electron Diffraction ◽  
Strain Field ◽  
Elastic Strain ◽  
Strain Analysis ◽  
Local Strain ◽  
Contrast Imaging ◽  
Strain Characterization ◽  
Physical Mechanisms ◽  
Diffraction Contrast ◽  
Transmission Electron

There is a growing need for elastic strain characterization techniques with submicrometer resolution in several engineering technologies. In advanced material science and engineering the quantitative knowledge of elastic strain, e.g. at small particles or fibers in reinforced composite materials, can lead to a better understanding of the underlying physical mechanisms and thus to an optimization of material production processes. In advanced semiconductor processing and technology, the current size of micro-electronic devices requires an increasing effort in the analysis and characterization of localized strain. More than 30 years have passed since electron diffraction contrast imaging (EDCI) was used for the first time to analyse the local strain field in and around small coherent precipitates1. In later stages the same technique was used to identify straight dislocations by simulating the EDCI contrast resulting from the strain field of a dislocation and comparing it with experimental observations. Since then the technique was developed further by a small number of researchers, most of whom programmed their own dedicated algorithms to solve the problem of EDCI image simulation for the particular problem they were studying at the time.

Study of Tip-Surface Interactions in Scanning Tunneling Microscopy (STM) by Reflection Electron Microscopy (REM)

1990 ◽  
Vol 48 (1) ◽  
pp. 320-321
Author(s):  
W. Lo ◽  
J.C.H. Spence ◽  
M. Kuwabara
Keyword(s):  
High Resolution ◽  
Elastic Strain ◽  
Tunneling Current ◽  
Surface Damage ◽  
Surface Interactions ◽  
Graphite Surface ◽  
Scanning Tunneling ◽  
Large Area ◽  
Tunneling Microscopy ◽  
High Resolution Tem

Work on the integration of STM with REM has demonstrated the usefulness of this combination. The STM has been designed to replace the side entry holder of a commercial Philips 400T TEM. It allows simultaneous REM imaging of the tip/sample region of the STM (see fig. 1). The REM technique offers nigh sensitivity to strain (<10−4) through diffraction contrast and high resolution (<lnm) along the unforeshortened direction. It is an ideal technique to use for studying tip/surface interactions in STM.The elastic strain associated with tunnelling was first imaged on cleaved, highly doped (S doped, 5 × 1018cm-3) InP(110). The tip and surface damage observed provided strong evidence that the strain was caused by tip/surface contact, most likely through an insulating adsorbate layer. This is consistent with the picture that tunnelling in air, liquid or ordinary vacuum (such as in a TEM) occurs through a layer of contamination. The tip, under servo control, must compress the insulating contamination layer in order to get close enough to the sample to tunnel. The contaminant thereby transmits the stress to the sample. Elastic strain while tunnelling from graphite has been detected by others, but never directly imaged before. Recent results using the STM/REM combination has yielded the first direct evidence of strain while tunnelling from graphite. Figure 2 shows a graphite surface elastically strained by the STM tip while tunnelling (It=3nA, Vtip=−20mV). Video images of other graphite surfaces show a reversible strain feature following the tip as it is scanned. The elastic strain field is sometimes seen to extend hundreds of nanometers from the tip. Also commonly observed while tunnelling from graphite is an increase in the RHEED intensity of the scanned region (see fig.3). Debris is seen on the tip and along the left edges of the brightened scan region of figure 4, suggesting that tip abrasion of the surface has occurred. High resolution TEM images of other tips show what appear to be attached graphite flakes. The removal of contamination, possibly along with the top few layers of graphite, seems a likely explanation for the observed increase in RHEED reflectivity. These results are not inconsistent with the “sliding planes” model of tunnelling on graphite“. Here, it was proposed that the force due to the tunnelling probe acts over a large area, causing shear of the graphite planes when the tip is scanned. The tunneling current is then modulated as the planes of graphite slide in and out of registry. The possiblity of true vacuum tunnelling from the cleaned graphite surface has not been ruled out. STM work function measurements are needed to test this.

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