Both pentane and isoprene are excreted in human breath. Although pentane is considered an index of lipid peroxidation, the significance of isoprene is unknown. Having a similar boiling point, these two hydrocarbons are difficult to separate by gas chromatography. We separated pentane from isoprene on both a Poraplot Q and a Poraplot U column, injecting single-breath samples directly into a gas ...

AIM To test the hypothesis that complications of neonatal intensive care are related to increased oxygen derived free radical activity, using breath pentane as a marker of lipid peroxidation. METHODS Exhaled breath was collected daily from 57 ventilated preterm infants and pentane concentration measured by gas chromatography. RESULTS High peak pentane exhalation was significantly associated...

the nitrite ® nitro isomerization in nitritopentaamine cobalt (iii) halides has been known. in this paper, the effect of the size of the counter ions (noncoordinated groups) on the rate of isomerization in nitritopentaamine cobalt (iii) halides, is reported. the rate of isomerization is decreased by increasing the size of the counter ions. this decrease is explained on the basis of steric inter...

The viscosities of dimethyl ether (DME, C2H6O) and of the fluorinated propene isomers 2,3,3,3-tetrafluoroprop-1-ene (R1234yf, C3H2F4) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) were measured in a combined temperature range from 242 K to 350 K at saturated liquid conditions. The instrument was a sealed gravitational capillary viscometer developed at NIST for volatile liquids. Calibration ...

Comparison of pentane extraction and steam distillation of intact leaves of Lippia dulcis (hierbia dulce, ex Mexico) yielded 2.13% (DW basis) vs. 0.13% for pentane extraction (18 h, shaking). Analyses of the oils showed (pentane; distilled): camphor (33.9, 21.2%), camphene (1.8, 12.7%), 6-methyl-5hepten-2-one (7.9, 3.4%), (+)-hernandulcin, the sweet sesquiterpene (9.2, 5.9%), 3-methyl-2cyclohex...

The relationship of exhaled ethane and n-pentane to exhaled NO, carbonylated proteins, and indoor/outdoor atmospheric pollutants were examined in order to evaluate ethane and n-pentane as potential markers of airway inflammation and/or oxidative stress. Exhaled NO and carbonylated proteins were found to have no significant associations with either ethane (p = 0.96 and p = 0.81, respectively) or...

Abstract: In this study, the liquid-liquid equilibria of the mixtures consisted of ethanol, water, and the main components of gasoline fuel: pentane, hexane, and cyclohexane were experimentally determined. This study is related to the phase behavior when water in atmosphere is absorbed into ethanol + gasoline fuel (gasohol) and then possibly separates into two liquid phases in an automobile fue...

In the present work, B-ZSM-5 zeolite membranes were synthesized on porous tubular α-alumina supports by several subsequence in situ crystallization hydrothermal treatments. The TiO2- Bohmite and ɣ- alumina intermediate layers were applied to improve the lattice matching between zeolite layer and the support. The uniform membrane intermediate layers with low permeation resistance were...

Pentane was measured in a mixture of guinea pig liver microsomes and carbontetrachloride (CCl4) in the presence of nicotineamide adenine dinucleotide phosphate (NADPH) and under anaerobic conditions by gas chromatography. Pentane of 0.2 pmol/mg protein/min was formed in the presence of NADPH without CCl4. Pentane formation increased to 2.0 pmol/mg protein/min in the presence of CCl4 and NADPH. ...

in this paper, absorption spectra of both solution and films of cyano azobenzene polymer are investigated. the analysis of overlapped absorption spectra of polymer, related to trans and cis isomers, shows that the population of cis isomers is higher than trans isomers. it means that, cyano azobenzene molecules have a folded structure in polymer, in thermal equilibrium. presence of cyano molecul...