Rubber Photogels. II.

1943 ◽  
Vol 16 (4) ◽  
pp. 783-789
Author(s):  
Henry P. Stevens
Keyword(s):  
Alcoholic Potash ◽  
Previous Communication ◽  
Southern Aspect

Abstract In a previous communication the writer has shown that the formation of gels from rubber sols on irradiation is often accompanied by an increase in weight so that the solvent and (or) sensitizer apparently reacts photochemically with the solute. The increase in weight of the rubber after removal of the solvent was found to be greater the more rapid the gelation of the sol. It was suggested that this increase in weight might result from products formed by reaction between the solvent and sensitizers independently of the rubber; the product in that case might be rubber physically associated with such photochemical products. This seemed unlikely, as prolonged extraction of the moist or dried photogels with acetone and alcoholic potash removed only a part of the increase. As a further check, a mixture of solvents and sensitizers without rubber was irradiated in sealed tubes and the products were examined. These experiments have been repeated by exposure to sunlight in a window with southern aspect for a whole year. In some cases small quantities of nonvolatile substances were obtained, but these were readily soluble in acetone and, therefore, did not account for the increase in weight, or at least for only a small part of it, and that part was acetone-soluble. It appears, therefore, that any reaction which takes place on insolation between the solvents, with or without additional sensitizers, cannot account for the observed increase in weight of dried photogels. The conclusion is reached that a photosynthesis has taken place, and that the gels consist of a rubber reaction product, at least where an increase in weight takes place.

The Nature of Vulcanization. Part IV (Continued)

1932 ◽  
Vol 5 (2) ◽  
pp. 117-118
Author(s):  
H. P. Stevens ◽  
W. H. Stevens
Keyword(s):  
Hydrochloric Acid ◽  
Extraction Method ◽  
Acid Mixture ◽  
Acid Extraction ◽  
Vulcanized Rubber ◽  
Alcoholic Potash ◽  
Previous Communication ◽  
Mineral Sulfides

Abstract In a previous communication the authors have discussed the limiting figure for combined sulfur in vulcanized rubber, and shown that under suitable circumstances the coefficient of vulcanization can exceed the figure of 47, which is that required by the formula C5H3S. It was thought that the combined sulfur in excess of this amount resulted from the substitution of sulfur for hydrogen. (Further information on this point will be found in the second part of this paper.) In the course of these experiments use was made of the ether-hydrochloric acid extraction method for the removal of mineral sulfides in soft vulcanized rubber. It was thought that this extraction method might not be suitable for use with vulcanites, since the amount of swelling produced by the ether was relatively inappreciable, and consequently the metallic sulfides were not necessarily decomposed. It was also thought that the acid mixture might react with a part of the rubber sulfide and result in a lower coefficient, which would depend on the time of extraction. It is known that vulcanite can be decomposed by the action of alcoholic potash, and the combined sulfur has been reduced in some cases to 26 per cent. It is reasonable to suppose that decomposition takes place in the presence of concentrated hydrochloric acid. In order to determine the extent to which the sulfide is decomposed by the action of the acid a series of extractions was made.

Further Ultrastructural Observations on Metastatic Nodules of Human Breast Cancer

1968 ◽  
Vol 26 ◽  
pp. 224-225
Author(s):  
John L. Swedo ◽  
R. W. Talley ◽  
John H. L. Watson
Keyword(s):  
Breast Cancer ◽  
Human Breast Cancer ◽  
Estrogen Therapy ◽  
Specimen Preparation ◽  
Human Breast ◽  
Autophagic Vacuoles ◽  
Previous Communication ◽  
Linear Profiles ◽  
Metastatic Nodule

Since the report, which described the ultrastructure of a metastatic nodule of human breast cancer after estrogen therapy, additional ultrastructural observations, including some which are correlative with pertinent findings in the literature concerning mycoplasmas, have been recorded concerning the same subject. Specimen preparation was identical to that in.The mitochondria possessed few cristae, and were deteriorated and vacuolated. They often contained particulates and fibrous structures, sometimes arranged in spindle-shaped bundles, Fig. 1. Another apparent aberration was the occurrence, Fig. 2 (arrows) of linear profiles of what seems to be SER, which lie between layers of RER, and are often recognizably continuous with them.It was noted that the structure of the round bodies, interpreted as within autophagic vacuoles in the previous communication, and of vesicular bodies, described morphologically closely resembled those of some mycoplasmas. Specifically, they simulated or reflected the various stages of replication reported for mycoplasmas grown on solid nutrient. Based on this observation, they are referred to here as “mycoplasma-like” structures, in anticipation of confirmatory evidence from investigations now in progress.

scholarly journals The secreto-motor effects in the cat's foot studied by the electrometer.

1904 ◽  
Vol 73 (488-496) ◽  
pp. 92-98 ◽  
Author(s):  
Augustus Desire Waller
Keyword(s):  
Sciatic Nerve ◽  
Single Stimulus ◽  
Motor Action ◽  
Voluntary Muscle ◽  
Previous Communication ◽  
The Difference ◽  
Single Response ◽  
Motor Effects

In a previous communication it was stated that the electrical signs a of secreto-motor action by tetanisation of the sciatic nerve are a demonstrable in the pads of a cat’s foot after death, best so during; the second half-hour after death, when the action of the nerve upon muscles of the limb has ceased. The subsequent study of these effects, by means of electrometer records, has brought out with great distinctness the chief classical events with which we are familiar in the case of the contraction of voluntary muscle, viz., the latency and course of a single response to a single stimulus, the super-position of two or more responses and the composition of tetanus, summation of stimuli, fatigue and recovery, and the staircase phenomenon. The difference between the muscular and the secreto-motor series of phenomena is principally a difference of time, the former being about 100 times more rapid than the latter.

82. Studies in the Ripening of Cheddar Cheese. IV. The Bacterial Flora of Cheese made from Milk of a Very Low Bacterial Count. V. The Influence of the Rennet Flora on the Flora of the Cheese. VI. The Influence of the Starter on the Ripening Process

1934 ◽  
Vol 5 (3) ◽  
pp. 185-196 ◽  
Author(s):  
L. A. Allen ◽  
N. R. Knowles
Keyword(s):  
Rapid Growth ◽  
Bacterial Flora ◽  
Cheddar Cheese ◽  
Bacterial Count ◽  
Nitrogen Compounds ◽  
Ripening Process ◽  
Early Stages ◽  
Previous Communication

In a previous communication (Allen (1)) it was shown that Cheddar cheese made from milk of a very low bacterial count (Grade A (T.T.)) exhibited a retarded rate of ripening, as evidenced by proteolysis and development of flavour and texture, when compared with similar cheese made from ordinary market milk, and the view was advanced that the miscellaneous flora of market milk produces sufficient proteolysis of the casein in the early stages of manufacture to provide the starter organisms with necessary nitrogen compounds for rapid growth.

Letters to the Editor

PEDIATRICS ◽  
1966 ◽  
Vol 37 (3) ◽  
pp. 533-534
Author(s):  
CLARENCE H. WEBB
Keyword(s):  
Emotional Responses ◽  
Self Esteem ◽  
Domestic Animals ◽  
Allergic Reactions ◽  
Letters To The Editor ◽  
Previous Communication

Dr. Horowitz' letter and the previous communication from Dr. Hugh Carithers Padiatrics 37:386, 1966) are welcome because of the added facets which they introduce to the fascinating topic of the interaction between children and their pets, as well as other domestic animals. My brief commentary was concerned largely with the prehistoric and historic association of man and his animal domestics, with a few remarks concerning shared infections; whole volumes could additionally be written about allergic reactions, emotional responses, the value of pets in training children in areas of responsibility and self-esteem, fears, myths, and legends.

Pyridylpyrrolido ligand in Ge(II) and Sn(II) chemistry: Synthesis, reactivity and catalytic application

2021 ◽  
Author(s):  
Sanjukta Pahar ◽  
Vishal Sharma ◽  
Srinu Tothadi ◽  
Sakya Singha Sen
Keyword(s):  
Catalytic Application ◽  
Previous Communication

In our previous communication, we have reported the synthesis of a new chlorogermylene (B) featuring a pyridylpyrrolido ligand. This study details the prepartion of a series of new germylenes and...

On Improvements in the Apparatus for Counting the Dust Particles in the Atmosphere

1890 ◽  
Vol 16 ◽  
pp. 135-172 ◽  
Author(s):  
John Aitken
Keyword(s):  
Dust Particles ◽  
Laboratory Work ◽  
Preliminary Work ◽  
Previous Communication

In a previous communication I described the apparatus first used for counting the dust particles in the atmosphere. That apparatus was constructed of such materials as could be easily obtained ready made, and was fitted together in such a way that any one acquainted with laboratory work could easily repeat the experiments. Though that apparatus is satisfactory enough for preliminary work, and gives fairly good results, yet it is evidently not suited for regular everyday use; and, besides that, there are certain defects in it which can be avoided in apparatus specially constructed.

scholarly journals Isotherms of hydrogen, carbon monoxide and their mixtures

1931 ◽  
Vol 134 (824) ◽  
pp. 502-512 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Pressure Range ◽  
Close Agreement ◽  
Gas Mixtures ◽  
Industrial Processes ◽  
Gaseous Mixtures ◽  
Previous Communication ◽  
New Apparatus ◽  
Temperature Ranges

In a previous communication from these laboratories by G. A. Scott an account was given of the determination of the isotherms of hydrogen, carbon monoxide and mixtures of the two in the molecular proportion 2 : 1, 1 : 1 and 1 : 2 over a pressure range up to 170 atmospheres and at a temperature of 25° C. Since the completion of that investigation new apparatus has been installed so that the pressure and temperature ranges might be extended; and in this paper are embodied the results of further determinations carried out at both 0° C. and 25° C. and over a pressure range extending up to 600 atmospheres. In pursuing this investigation further it is our endeavour to furnish information in regard to the gaseous mixtures in question over the pressure and temperature ranges now commonly used in industrial processes. The Isotherms of the Single Gases . A repetition in our new apparatus of the determinations previously made by Scott both for the single gases and gas mixtures at 25° C. and at pressures up to 170 atmospheres showed his figures to be in close agreement with our own, the variations never exceeding 0·1 per cent.

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