THE C H E M I C A L W O R L D THIS WEEK
dyes can also be used only for light to medium shades 'on thé filament fibers. Vat dyes will not deposit on the monofilament from alkaline solution but can be used by a modified vat-acid metliod to give light and medium shades. The fiber of X-51 as it comes out of the precipitating bath is bluish-white and semi-dull, the staple being slightly less lustrous than die monofilament. The index of refraction is 1.51. The individual fibers that make up the X-51 yarn are generally smaller dian those used in other yarns, which means that there are more strands to each thread, and this is claimed to be partially responsible for the pleasant, if somewhat firm, ""hand." The fiber has a melting point of about 560° F. but shrinks and shrivels below this point. X-51 fabrics can b e pressed at about the same temperatures used on nylon. The filaments have a dry tenacity of about 3.6 grams per denier with an elongation of 2 2 % . Comparable tenacity of the wet fiber is 3.2 grams per denier. The tenacity of staple fiber yarn is somewhat less. X-51 has the usual additional advantages of acrylic fibers: permanent creasing, quick drying, chemical resistance, and freedom from mildew, moth damage, and shrinking. Cyanamid says that they have not yet reached full production in the pilot plant and have made no decision on future production plans. However, they have
announced that they will soon begin construction of a plant near New Orleans which will produce substantial quantities of acrylonitrile and it may be assumed that a part of this production is earmarked for eventual use in the manufacture of X-51. SCIENCE Panray Corp· N o w Producing Anti-tubercular Drug
Add Panray Corp. to the list of firms producing the recently announced antitubercular drug isonicotinic acid hydrazide (C&EN, March 3, page 902). Panray says it has started production of the drug, and expects to investigate its use in the treatment of leprosy. The company is also conducting research on other homologs of the compound. Mucoprotein Factor Aids B o d y ' s Use of B12
A factor in gastric juices which is essential to bodily utilization of vitamin Bia has been discovered by scientists of New York Medical College, Flower-Fifth Ave. Hospital. The researchers have called the factor a glandular mucoprotein. The present phase of the studies is concerned with identifying the material.
The scientists say that it is present in the stomach of normal persons but not in patients ill with pernicious anemia. .Seven victims of the disease were given vitamin Bi2 orally with the mucoprotein and they recovered completely, it was stated. I t was suggested that the factor may b e produced from animal sources. The research team was headed by George B . Jerzy Glass. D e c a y Scheme for Gallium 67 Determined a t O a k Ridge
Three members of the analytical chemistry division of Oak Ridge National Laboratory have computed the decay scheme of gallium 67, a cyclotron-produced isotope which ORNL's medical division is investigating. The latter group believes that a much higher radiation dose may b e delivered to a tumor with gallium 67 than with gallium 72, currently used. Half-life of gallium 67 is 3.24 days; that of gallium 72 is only 14.3 hours. Gallium 67 is also said to have a less energetic gamma ray component. S7
3lGALLIUM"'
7
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(3.24D.) /
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The accompanying illustration shows a simplified version of the gallium 67 decay scheme. When the isotope was first considered as a possible therapeutic agent, it was almost cast aside because its decay scheme was unknown, thus making it impossible to calculate radiation dosages.
G E Summer
Fellowships
Applications are being received for General Electric science and mathematics fellowships open to high school teachers for specialized summer study in 1952 at Union College, Case Institute of Technology, and Rensselaer Polytechnic Institute. The program is open to 100 science teachers for study at Union and Case, and 50 mathematics teachers at Rensselaer. GE science fellows will be selected by the colleges on a competitive basis from 24 states and the District of Columbia, A N D
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