Acetylene

Concentrations of TCE, cis-DCE and VC were measured using 8610GC instrument with purge-trap system (SRI, USA), photoionization detector and MXT-VOL stationary column. The purge-trap autosampler was equipped with carbon-sieve trap and Tenax^™ trap, allowing the detection of highly volatile VC. 50 μL of water sample was injected in 5 mL deionized water in glass tubes, and loaded into the 10-port autosampler. The GC was programmed at 40°C for 6 minutes, then ramped to 60°C in 2 minutes, held at 60°C for 10 minutes. Hydrocarbon gases (methane, ethene, ethane and acetylene) in headspace of electrolytic cell were analyzed through a Model 310 GC (SRI, USA) with flame ionization detector and Haysep-T column. 100 μL of headspace gas was sampled and injected from an on-column port. The temperature program applied was: heat column from 40 to 140°C at a rate of 15°C min⁻¹, hold 140°C for 1 minute, and cool to 40°C at a rate of 20°C min⁻¹. Chloride ion concentration was analyzed by Dionex DX-120 ion chromatograph. After each experiment, an aliquot 0.2 to 0.5 ml of supernatant was transferred into 5 mL vials which had been pre-filled with de-ionized water (> 18 M3), then filtered by 0.45μm pore size filter paper prior to final analysis. pH, conductivity and oxidation-reduction potential (ORP) of the electrolyte were measured by pH meter, conductivity meter and ORP meter with corresponding microprobes (Microelectro, USA). The microprobes allow the measurement on these parameters using small amount of liquid (≈0.2 mL).

The LVEDV (determined by echocardiography) and PCWP data were used to construct LV end-diastolic pressure-volume curves using the following exponential model, which has been described previously^{5 (link)}: P=P∞ (exp^a(V–V0)−1) where P is PCWP; P∞, pressure asymptote of the curve; V, LVEDV index; V0, equilibrium volume or the volume at which P=0 mm Hg, and a is a constant that characterizes the chamber stiffness. LV end-diastolic transmural pressure-volume curves also were constructed using estimated transmural pressure (PCWP–right atrial pressure).^{18 (link)} The PCWP and stroke volume (SV) data obtained by the acetelyene rebreathing method were used to construct Frank-Starling curves. The LVEDV, SV, and mean atrial pressure data were used to construct preload recruitable stroke work(PRSW) relationships. Circumferential LV wall stress (σ_c) and strain were determined as previously described^{5 (link)} by use of the modified Laplace relation: σ_c=Pb/h[1–(h/2b)][1–(hb/2a2)], where P is estimated transmural pressure; h, LV midwall thickness; a, major semiaxis; and b, minor semiaxis. The LV midwall thickness and semiaxis measurements were calculated from the transthoracic echocardiographic images. Ventricular strain was calculated as follows: strain=(V–V_min)/V_min, where the smallest end-diastolic volume measured during cardiac unloading (V_min) was determined. This value was subtracted from the end-diastolic volume at each loading and unloading condition (V–V_min). The resulting data were used to construct stress-strain plots, which were modeled by an exponential equation (y=ae^bx). Total arterial compliance was estimated by the ratio between the acetylene rebreathing-derived SV and pulse pressure.^{19 (link)} Effective arterial elastance was estimated as the LV end-systolic pressure divided by SV, where LV end-systolic pressure was estimated as 0.9×systolic blood pressure.^{20 (link),21 (link)}