Underwater life support based on immobilized oxygen carriers

One of the primary problems that hinders humans in their efforts to explore and develop the ocean realms is the lack of a ready supply of oxygen. Practical methods have not yet been devised for using the vast amount of oxygen dissolved in ocean waters for human life support in an undersea environment. Fish and other water-breathing animals have solved this problem by utilizing hemoglobin as a molecular oxygen pump. To achieve a similar oxygen extraction capability, we have explored various methods of oxygen extraction that are based on immobilized forms of hemoglobin. Improved methods for immobilizing hemoglobin or other oxygen carrying molecules and a method for extracting the available dissolved oxygen from natural waters and other fluids are described. The techniques that have been developed allow for immobilization of oxygen carriers at high concentration in a state where they are capable of reversible oxygen binding, and also allow for regeneration of the carrier in the event of oxidation of the oxygen-binding site.     

Diazepines—XXII : 13C NMR spectra of 2,3-dihydro-1,4-diazepinium salts

The ¹³C NMR spectra of a number of 2,3-dihdyro-1,4-diazepinium salts, like ¹H NMR spectra, confirm shape, and charge distribution for these compounds. The ring has a half-chair shape which is inverting rapidly at room temperature. The atoms in the conjugated portion of the ring show alternating polarity, and phenyl groups attached to these positions act, respectively, as electron-donors or electron-acceptors. A methyl substituent in the saturated portion of the ring shows equal preference for quasi-equatorial and quasi-axial conformations. Some comparisons are drawn between present results and similar results obtained with related benzene derivatives.     

Analysis of metoprolol enantiomers in human serum by liquid chromatography on a cellulose-based chiral stationary phase

Metoprolol is a lipophilic, cardioselective beta-adrenergic blocking agent commercially available as a racemic compound. A normal phase high-performance liquid chromatographic method was developed to directly determine individual enantiomeric concentrations of metoprolol in human serum. Separation of the enantiomers was accomplished by a cellulose-tris(3,5-dimethylphenylcarbamate) chiral stationary phase. Metoprolol enantiomers were detected by means of fluorescence with excitation and emission wavelengths of 275 and 315 nm, respectively. Standard curves were linear over the concentration range 12.5-400 ng/ml for each enantiomer. Within-day coefficient of variation was less than 15% at all concentrations and the between-day coefficient of variation ranged from 4.1 to 11.2%. The limit of detection was determined to be 5 ng/ml for each enantiomer and the stereoselective resolution (alpha) of R- and S-metoprolol was 3.08. The assay was employed to determine enantiomeric serum concentrations of metoprolol in healthy male volunteers.     

Electron localization for a model of layered metallic structures

Several exact results are presented for a one-dimensional tight-binding model of layered binary metallic structures for the cases of arbitrary, random, incommensurate, and commensurate layer sequences.     

Stark-hyperfine measurements in K = 0 and K = 1 states of NH3

High-resolution Stark-hyperfine transition measurements have been made on the J = 1, K = 0 and J = 1, K = 1 levels of ammonia using molecular beam electric resonance spectroscopy. The dipole moments measured are μ(J = 1, K = 0) = 1.47149(15) D and μ(J = 1, K = 1) = 1.47179(15) D. The polarizability anisotropy was found to be positive and hyperfine properties for both states were accurately measured.     

Off-diagonal disorder and X-ray edges

The combined effects of off-diagonal disorder and electron-hole pair production (the X-ray edge effect) are studied for a one-dimensional Anderson model of a liquid metal with a half-full band.