PubMed · 13265821
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L FEINMANN, G L LEATHART, G B PENDLENTON. 1955-10-15. Single-breath continuous carbon dioxide analysis.. https://doi.org/10.1038/176739a0
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The yields of nitrate and nitrite from decomposition of peroxynitrite in phosphate buffer at 37 degrees C were determined in the pH range 1-14. The NO(2)(-)/NO(3)(-) yields showed a stepwise variation with pH, with inflection points at approximately pH 3.1, 5.8, 6.8, 8.0, and 11.9. Nitrite formation increased strongly above pH 7 at the expense of nitrate, but above pH 12 nitrate again became the major product (80% at pH 14). At this pH, the Arrhenius parameters were E(a)=24.1+/-0.2kcal mol(-1) and A=(4.9+/-1.3)x10(12)s(-1). The yields of NO(2)(-), NO(3)(-), and O(2) measured at pH 5.8, 7.4, and 8.5 as a function of the initial peroxynitrite concentration (50-1000 microM) were linear only at pH 5.8. In the presence of carbon dioxide, oxygen production at pH 7.5 and pH 10 was found to be linear on the CO(2) concentration. The experimental observations were satisfactorily reproduced by kinetic simulations including principal component analyses. These data strongly suggest that the chemistry of peroxynitrite is exclusively mediated by z.rad;NO(2) and HO(z.rad;) radicals in the absence, and by z.rad;NO(2) and CO(3)(z.rad;-) radicals in the presence of CO(2).
An inclusion complex between imazalil (IMZ), a selected fungicide, and cyclomaltoheptaose (beta-cyclodextrin, betaCD) was obtained using supercritical fluid carbon dioxide. The best preparation conditions were determined, and the inclusion complex was investigated by means of 1H NMR spectroscopy in aqueous solution and 13C CPMAS NMR spectroscopy in the solid state. Information on the geometry of the betaCD/IMZ complex was obtained from ROESY spectroscopy, while the dynamics of the inclusion complex in the kilohertz range was obtained from the proton spin-lattice relaxation times in the rotating frame, T(1rho) (1H).
The green monkey orange (Strychnos spinosa Lam., Loganiaceae), a tree indigenous to tropical and subtropical Africa, produces juicy, sweet-sour, yellow fruits containing numerous hard brown seeds. The species has recently been introduced into Israel as a potential new commercial crop. However, little is known about its agronomical performance, fruit development and ripening, or postharvest physiology. The current study shows that during ripening in storage, the peel color changes from green to yellow, accompanied by a climacteric burst of ethylene and carbon dioxide emission. Total soluble solids slightly increased during storage, whereas total titratable acidity and pH did not change significantly. The major sugars that accumulated during ripening in storage were sucrose, glucose, and fructose, and the main acids, citric and malic acids. The main volatiles present in the peel of ripe fruits were phenylpropanoids, trans-isoeugenol being the major compound.