Structure and properties of ethylene—methacrylic acid copolymers and their sodium salts: Dielectric and proton magnetic relaxation studies

Dielectric and proton magnetic relaxation data have been obtained for an ethylene-methacrylic acid copolymer (containing about 4 mole% methacrylic acid units) and its 53% ionised sodium salt. The degrees of crystallinity and percentage ionisation of the samples investigated were estimated by infra-red methods. The dielectric results were obtained principally in the frequency range 100 Hz to 10 kHz and at temperatures ranging from 80° to – 120°. A few results are also reported at frequencies down to 0·1 Hz and up to 100 MHz. For the acid copolymer, two dielectric loss regions are observed and these are correlated with the reported mechanical β′- and γa-processes respectively. The partly ionised copolymer exhibits three dielectric relaxation regions which correlate with the mechanical α-, β- and γa-relaxations respectively. In addition, a dielectric peak appears at about —40° in the presence of absorbed water, a result similar to that found in the polyamides. The proton magnetic relaxation results were obtained by pulse methods which yielded the spin-lattice relaxation times T₁ (at 30 MHz) and T_1p (at kilohertz frequencies) as a function of temperature from ?180° to 100°. Two components were generally observed for T_1p. For the acid copolymer the β′- and γ-processes have been observed from these results, as well as a lower-temperature (δ) process which has not been detected by the mechanical or dielectric methods. For the sodium salt the γ- and δ-processes are also found, in addition to a high-temperature process in the region of the merged α- and β-processes. The present data are consistent with previous assignments for the β′-, α-, β- and γ-processes. The ‘water’ relaxation appears to involve some rotation of water molecules, or of ionic segments to which water molecules are attached, in the proposed ionic domains. The δ-process is ascribed to the rotations of methyl groups present in the methacrylic acid units.     

Report of the instrumental techniques committee AOCS, 1971–72

Summary As described in this report, the Instrumental Techniques Committee has in various stages of progress several methods which will be proposed for adoption as official methods of the AOCS. For convenience, these proposed methods and their present status are summarized in Table II. Report of collaborative work from Government, Industrial and Academic Laboratories by members of ARS, USDA, Southern and Eastern Marketing and Nutrition Divisions; Anderson Clayton and Co., Food Division; Unilever Research; and A.E. Staley Mfg. Co.     

Investigations on the primary structure of human plasminogen. Further evidence for sequence homology

A relatively rare benign tumor of the fallopian tube is presented, i.e. an intramural leiomyoma, which was incidentally found during histologic examination of the tubal isthmus excised for sterilization. The literature is briefly reviewed.     

V/Q mismatch without pulmonary emboli in children with histoplasmosis

In two children with histoplasmosis pulmonary perfusion and ventilation studies revealed mismatched abnormalities characterized by almost unilaterally absent perfusion but normal ventilation in the right lung. Chest roentgenograms demonstrated right hilar enlargement and pulmonary contrast angiograms revealed narrowing of the right pulmonary arteries by extrinsic fibrotic granulomata but no pulmonary emboli were present. Fibrosing mediastinitis due to histoplasmosis was found by mediastinoscopic examination in one of the patients. Non-embolic causes of V/Q mismatch lung imaging are discussed briefly, and the correlation with clinical findings is stressed for the diagnosis of pulmonary emboli.     

Physical and chemical properties of selected metal complexes of gossypol

In order to understand the chemistry of complexes of gossypol several metal ion-gossypol complexes have been synthesized. They do not melt below 300 C and turn dark in color after drying in a vacuum oven. The stability constants and stoichiometry of CO⁺⁺, Ni⁺⁺ and Cu⁺⁺ gossypol complexes have been established by several analytical and spectroscopic techniques. The infrared spectra of solid samples show a greatly diminished absorption at 2.8μ and the 6.2μ band is shifted to a lower wavelength indicating binding of the metal through the hydroxyl and aldehyde groups. Electronic absorption spectra also support this conclusion. Bis(o-carboxyphenylimino) gossypol gives a copper (II) complex, where the carboxylic group, but not the phenolic hydroxyl group, of the gossypol is ionized. In this instance copper ion is bound to the carboxy oxygen and nitrogen of the imine. Resident Postdoctoral Research Associate 1967–1968. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Sex differences in children's response to training on a visual-spatial test.

In a study with 133 children in Grades 1, 3, and 5, a brief training procedure designed to improve performance on the Children's Embedded Figures Test, a test of visual ability, resulted in significant improvement for girls but not for boys. No sex difference was observed among children receiving this training. The implications for theories of sex differences in visual–spatial ability are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)