MOLECULAR AREAS OF SOAPS AT THE SURFACE OF LATEX PARTICLES

1960 ◽  
Vol 38 (5) ◽  
pp. 668-680 ◽  
Author(s):  
R. J. Orr ◽  
L. Breitman
Keyword(s):  
Surface Tension ◽  
Polyethylene Oxide ◽  
Latex Particle ◽  
Molecular Area ◽  
Electron Microscopic ◽  
Latex Particles ◽  
Conventional Methods ◽  
Repulsive Forces ◽  
Microscopic Techniques ◽  
Soap Molecule

The molecular area (i.e., the area occupied by a molecule of soap adsorbed on a surface) has been determined for a number of anionic, cationic, and non-ionic emulsifiers, adsorbed on latex particles. Measurements were made by surface tension and electron microscopic techniques. The composition of the polymer did not affect the molecular area of either anionic or cationic soaps. When a mixture of non-ionic and anionic soaps was used, interaction between the soaps prevented application of the conventional methods for measuring molecular area. The interaction is manifested by a decrease in the area occupied by an anionic soap molecule which can be explained in terms of reduction in electrostatic repulsive forces between ionic soap molecules. The configuration of the polyethylene oxide chain of the non-ionic on the surface of the latex particle is deduced to be that of caterpillarlike folds.

Polarity Determination in Sphalerite and Wurtzite Structures

1990 ◽  
Vol 48 (2) ◽  
pp. 500-501
Author(s):  
Stuart McKernan ◽  
C. Barry Carter
Keyword(s):  
Opposite Polarity ◽  
Single Domain ◽  
Polar Material ◽  
Electron Microscopic ◽  
Dynamical Interaction ◽  
X Ray ◽  
Polarity Determination ◽  
The Absolute ◽  
Microscopic Techniques

The determination of the absolute polarity of a polar material is often crucial to the understanding of the defects which occur in such materials. Several methods exist by which this determination may be performed. In bulk, single-domain specimens, macroscopic techniques may be used, such as the different etching behavior, using the appropriate etchant, of surfaces with opposite polarity. X-ray measurements under conditions where Friedel’s law (which means that the intensity of reflections from planes of opposite polarity are indistinguishable) breaks down can also be used to determine the absolute polarity of bulk, single-domain specimens. On the microscopic scale, and particularly where antiphase boundaries (APBs), which separate regions of opposite polarity exist, electron microscopic techniques must be employed. Two techniques are commonly practised; the first [1], involves the dynamical interaction of hoLz lines which interfere constructively or destructively with the zero order reflection, depending on the crystal polarity. The crystal polarity can therefore be directly deduced from the relative intensity of these interactions.

Techniques For The Preparation of Tissue Samples Containing Injectable Polymer Microcapsules

1985 ◽  
Vol 43 ◽  
pp. 710-711
Author(s):  
G.E. Visscher ◽  
R. L. Robison ◽  
G. J. Argentieri
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Gastrocnemius Muscle ◽  
Degradation Process ◽  
Delivery Systems ◽  
Tissue Reaction ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Injectable Polymer ◽  
Microscopic Techniques

The use of various bioerodable polymers as drug delivery systems has gained considerable interest in recent years. Among some of the shapes used as delivery systems are films, rods and microcapsules. The work presented here will deal with the techniques we have utilized for the analysis of the tissue reaction to and actual biodegradation of injectable microcapsules. This work has utilized light microscopic (LM), transmission (TEM) and scanning (SEM) electron microscopic techniques. The design of our studies has utilized methodology that would; 1. best characterize the actual degradation process without artifacts introduced by fixation procedures and 2. allow for reproducible results.In our studies, the gastrocnemius muscle of the rat was chosen as the injection site. Prior to the injection of microcapsules the skin above the sites was shaved and tattooed for later recognition and recovery. 1.0 cc syringes were loaded with the desired quantity of microcapsules and the vehicle (0.5% hydroxypropylmethycellulose) drawn up. The syringes were agitated to suspend the microcapsules in the injection vehicle.

Ultrastructural Immunocytochemistry of Five Rat Pituitary Adenomas

1980 ◽  
Vol 38 ◽  
pp. 724-725
Author(s):  
D. J. McComb ◽  
N. Ryan ◽  
E. Horvath ◽  
K. Kovacs ◽  
E. Nagy ◽  
...  
Keyword(s):  
Pituitary Adenomas ◽  
Pituitary Tumors ◽  
Electron Microscopic ◽  
Electron Microscopic Immunocytochemistry ◽  
Transmission Electron ◽  
Rat Pituitary ◽  
Radiation Induced ◽  
Group 5 ◽  
Group 2 ◽  
Microscopic Techniques

Conventional light and electron microscopic techniques failed to clarify the cellular composition and derivation of spontaneous and induced, intrasellar and transplanted pituitary adenomas in rats (1). In the present work, electron microscopic immunocytochemistry was applied to evaluate five adenohypo-physial tumors using a technique described by Moriarty and Garner (2). Spontaneously occurring pituitary adenomas (group 1) were harvested from aging female Long-Evans rats. R-Amsterdam rats were treated with 2 x 1.0 mg estrone acetate (HogivaI) s.c. weekly for 6 months. Pituitary adenomas in excess of 30 mg were removed from these animals to make up the tumors of group 2. Groups 3 and 4 consisted of estrogen-induced autonomous transplan¬ted pituitary tumors MtT.WlO and MtT.F4. Group 5 was a radiation-induced transplanted autonomous pituitary tumor MtT.W5. The tumors of groups 3,4 and 5 were allowed to proliferate in host rats 6-8 weeks prior to removal for processing. Tissue was processed for transmission electron microscopy (glutaraldehyde fixation, OsO4 postfixation and epoxy resin embedding), and electron microscopic immunocytochemistry (3% paraformaldehyde fixation and Araldite embedding).

THE ALVEOLAR LINING LAYER

PEDIATRICS ◽  
1962 ◽  
Vol 30 (2) ◽  
pp. 324-330
Author(s):  
Mary Ellen Avery
Keyword(s):  
Surface Tension ◽  
Secretory Activity ◽  
Hyaline Membrane Disease ◽  
Normal Lung ◽  
Elastic Recoil ◽  
Alveolar Cells ◽  
Electron Microscopic ◽  
Hyaline Membrane ◽  
Surface Active ◽  
Air Liquid Interface

The alveoli of the normal lung are lined by a substance which exerts surface tension at the air-liquid interface. In the expanded lung the tension is high and operates to increase the elastic recoil of the lung. In the lung at low volumes the surface tension becomes extremely low. This confers stability on the airspaces and thus prevents atelectasis. This lining layer is a lipoprotein film, which is not found where alveoli are still lined by cuboidal epithelium. Its time of appearance coincides with the appearance of alveolar lining cells. Electron microscopic evidence of secretory activity in alveolar cells suggests that they may be the source of the surface-active film. The normal alveolar lining layer is not present in lungs of infants who die from profound atelectasis and hyaline membrane disease. Whether its absence is a failure of development or due to inactivation is not established.

Release and Recycling of the Readily Releasable Vesicle Population in a Synapse Possessing No Reserve Population

2007 ◽  
Vol 97 (6) ◽  
pp. 4048-4057 ◽  
Author(s):  
J. H. Koenig ◽  
Kazuo Ikeda
Keyword(s):  
High Frequency ◽  
Active Zone ◽  
Neuromuscular Junctions ◽  
Recycling Rate ◽  
Spontaneous Release ◽  
Electron Microscopic ◽  
Single Action ◽  
Active Zones ◽  
Evoked Activity ◽  
Microscopic Techniques

We previously demonstrated that the tergotrochanteral muscle (TTM) of Drosophila is innervated by unique synapses that possess a small readily releasable/recycling vesicle population (active zone population), but not the larger reserve vesicle population observed at other neuromuscular junctions in this animal. Using light and electron microscopic techniques and intracellular recording from the G1 muscle fiber of the TTM, the release and recycling characteristics of the readily releasable/recycling population were observed without any possible contribution from a reserve population. Our results indicate 1) the total number of vesicles in synapses presynaptic to the G1 fiber correlates with the total number of quanta that can be released onto this fiber; 2) the number of quanta released by a single action potential onto the G1 fiber is about one half the number of morphologically “docked” vesicles in active zones onto the G1, and this ratio decreases in a partially depleted state; 3) the recycling rate at 1-Hz stimulation, a frequency that does not cause any depression, is 0.24 recycled vesicle/active zone/s; and 4) normal-appearing spontaneous release occurs from the active zone vesicle population and, unlike synapses that possess a reserve population, the frequency of this release is reduced after high-frequency evoked activity.

Effect of Bonding Pressure on Transient Liquid Phase Bonding Joint Microstructure and Properties of T91/12Cr2MoWVTiB

2010 ◽  
Vol 97-101 ◽  
pp. 107-110 ◽  
Author(s):  
Si Jie Chen ◽  
Si Jing Guo ◽  
Feng Liang
Keyword(s):  
Liquid Phase ◽  
Transient Liquid Phase ◽  
Optical Microscope ◽  
Isothermal Solidification ◽  
Transient Liquid Phase Bonding ◽  
Bonded Joints ◽  
Electron Microscopic ◽  
Bonding Pressure ◽  
Scanning Electron Microscopic ◽  
Microscopic Techniques

T91/12Cr2MoWVTiB was bonded by transient liquid phase bonding process with different pressures, one commercial FeNiCrSiB was used as the interlayer. The microstructure and components distribution of the bonded joints were examined by optical microscope and scanning electron microscopic techniques. Furthermore, the properties of the joints were also tested. The results indicate that with the increase of the pressure – from 2 MPa to 6 MPa – the microstructures and mechanical properties were improved, and more similar to those base alloys. A theoretical study also revealed that the isothermal solidification complication time can be shorter, because the maximum liquid width was reduced with the existence of pressure.

Undergraduate Students’ Understanding of Surface Tension Considering Molecular Area

2020 ◽  
Vol 97 (11) ◽  
pp. 3937-3947
Author(s):  
Chulkyu Park ◽  
Chang Youn Lee ◽  
Hun-Gi Hong
Keyword(s):  
Surface Tension ◽  
Undergraduate Students ◽  
Molecular Area
Sign in / Sign up

Export Citation Format

Share Document