Volatile organic compounds (VOCs) are organic chemical substances that volatilize easily in ambient air at normal temperature and pressure. VOCs in human expired gas have been reported to be useful in the diagnosis of various diseases, but measurement of VOCs in human expired gas is technically dif cult because the concentrations in expired gas are extremely low and almost the same as the concentrations in ambient air. Accurate VOC measurement usually requires a large system, and no VOC measuring systems suitable for clinical practice are available. We developed a compact, simple, double cold trap system that can measure the concentrations of VOCs originating in humans. Our system detects a limited number of VOCs with very high sensitivity at concentrations as low as 0.05 ppb. We evaluated the reproducibility of our system and measured VOCs in ambient air, puri ed air, and human expired gas from smokers, non-smokers, and patients. Errors of ±10% seem unavoidable in our system. Our veri cation experiment using human expired gas strongly suggests that the reproducibility and detection sensitivity of our system allow the detection of most VOCs in human expired gas.
A new concept expired gas measurement system used double cold-trap method was developed. The system could detect selectively volatile organic compound (VOC) derived from the human body. The gas chromatography (GC) profiles of healthy volunteer's expired gas collected by our system were analyzed. As a result, 60 VOCs were detected from the healthy volunteer's expired gas. We examined 14 VOCs among them further, which could be converted to the concentration from the GC profiles. The concentration of almost VOCs decreased when the subjects inspired purified air compared with the atmosphere. On the other hand, isoprene was almost the same. It was strongly suggested that these VOCs were derived from the human body because the concentration of these VOCs in the atmosphere were nearly zero. Expired gas of two sleep apnea syndrome (SAS) patients were analyzed as preliminary study. As a result of the study, the concentration of some VOCs contained in the expired gas of the SAS patients showed higher value than a healthy controls.
We show that the integration of a 1-cocycle I(X) of the space of long knots in R 3 over the Fox-Hatcher 1-cycles gives rise to a Vassiliev invariant of order exactly three. This result can be seen as a continuation of the previous work of the second named author [13], proving that the integration of I(X) over the Gramain 1-cycles is the Casson invariant, the unique nontrivial Vassiliev invariant of order two (up to scalar multiplications). The result in the present paper is also analogous to part of Mortier's result [10]. Our result differs from, but is motivated by, Mortier's one in that the 1-cocycle I(X) is given by the configuration space integrals associated with graphs while Mortier's cocycle is obtained in a combinatorial way.
We show that the integration of a 1-cocycle I (X) of the space of long knots in ޒ 3 over the Fox-Hatcher 1-cycles gives rise to a Vassiliev invariant of order exactly three. This result can be seen as a continuation of the previous work of the Sakai (2011), proving that the integration of I (X) over the Gramain 1-cycles is the Casson invariant, the unique nontrivial Vassiliev invariant of order two (up to scalar multiplications). The result in the present paper is also analogous to part of Mortier's result (2015). Our result differs from, but is motivated by, Mortier's one in that the 1-cocycle I (X) is given by the configuration space integrals associated with graphs while Mortier's cocycle is obtained in a combinatorial way.Sakai is partially supported by JSPS KAKENHI Grant Number 20K03608.
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