Equilibrium Conditions for Semiclathrate Hydrates Formed with CO₂, N₂, or CH₄ in the Presence of Tri‑<i>n</i>‑butylphosphine Oxide

We measured the thermodynamic stability conditions for the N₂, CO₂, or CH₄ semiclathrate hydrate formed from the aqueous solution of tri-<i>n</i>-butylphosphine oxide (TBPO) at 26 wt %, corresponding to the stoichiometric composition for TBPO·34.5H₂O. The measurements were performed in the temperature range 283.71–300.34 K and pressure range 0.35–19.43 MPa with the use of an isochoric equilibrium step-heating pressure-search method. The results showed that the presence of TBPO made these semiclathrate hydrates much more stable than the corresponding pure N₂, CO₂, and CH₄ hydrates. At a given temperature, the semiclathrate hydrate of 26 wt % TBPO solution + CH₄ was more stable than that of 26 wt % TBPO solution + CO₂, which in turn was more stable than that of 26 wt % TBPO solution + N₂. We analyzed the phase equilibrium data using the Clausius–Clapeyron equation and found that, in the pressure range 0–20 MPa, the mean dissociation enthalpies for the semiclathrate hydrate systems of 26 wt % TBPO solution + N₂, 26 wt % TBPO solution + CO₂, and 26 wt % TBPO solution + CH₄ were 177.75, 206.23, and 159.00 kJ·mol^–1, respectively

Phase Equilibria and Dissociation Enthalpies of Hydrogen Semi-Clathrate Hydrate with Tetrabutyl Ammonium Nitrate

This paper reports the experimentally determined thermodynamic stability conditions for the hydrogen semiclathrate hydrate generated from tetrabutyl ammonium nitrate (TBANO₃) aqueous solutions at two mole fractions, 0.037 and 0.030, corresponding to the stoichiometric composition for TBANO₃·26H₂O and TBANO₃·32H₂O, respectively. The experiments for this three-component TBANO₃ + water + hydrogen system were performed in the temperature range of (281.9 to 284.9) K and pressure range of (9.09 to 31.98) MPa with using a “full view” sapphire cell. An isochoric equilibrium step-heating pressure search method was employed to determine the phase boundary between hydrate–liquid–vapor (H-L-V) phases and liquid–vapor (L-V) phases. The results showed that the semiclathrate hydrate of TBANO₃·26H₂O + H₂ is more stable than that of TBANO₃·32H₂O + H₂, with both of these semiclathrate hydrates being much more stable than pure hydrogen hydrate. The obtained phase equilibria data were analyzed using the Clausius–Clapeyron equation to determine the dissociation enthalpy at the pressure range from (9 to 32) MPa. It was found that the mean dissociation enthalpies for the hydrogen–TBANO₃·26H₂O and hydrogen–TBANO₃·32H₂O clathrate hydrate systems were 322.53 kJ·mol^–1 and 340.23 kJ·mol^–1, respectively

The Effects of Season of Birth on the Inflammatory Response to Psychological Stress in Hainan Island, China

<div><p>Season of birth (SOB) has been investigated as one of the environmental factors that might epigenetically determine the physiology of individuals. This study investigated the role of SOB in the association between Quality of Life (QOL), a proxy of psychological stress status, and C-reactive protein (CRP) concentration (i.e., inflammatory status) among 1,085 adults (aged 20–57 years old) in Hainan Island, China. High sensitivity CRP concentration was measured in dried blood spot samples, while the abbreviated version of the World Health Organization’s QOL questionnaire was used to gather information on six QOL domains. Analysis stratified by three historically distinct age groups revealed a significant association between CRP concentration, SOB, QOL and an interaction between SOB and QOL among the youngest and oldest groups. In the oldest group, those born in the dry season had a higher CRP concentration with worse QOL whereas in the youngest group, there was a higher CRP concentration with better QOL. Annual per capita rice production, a proxy of population nutritional status in the year of birth, was found to predict CRP concentration only among the second oldest group. These findings suggest that the early environment might affect the immune response to psychological stress in adulthood and that its effect may differ by the time period in which people were born.</p></div

Characteristics of included and excluded participants (aged 20–57 years old).

<p>^a: Quality of Life was scored by WHOQOL-BREF.</p><p>^b: Student’s t-test for continuous values and Pearson’s chi-square test for categorical values were conducted to examine if there were differences for variable scores between the participants and those who were excluded.</p><p>^c: Median and inter-quartile range is shown for C-reactive protein concentration.</p><p>Characteristics of included and excluded participants (aged 20–57 years old).</p

Average monthly temperature and rainfall in Hainan Island, China (2000–2012).

<p>Data source: World Weater Online.</p