Dry water stores 175 v(STP)/v methane at 2.7 MPa and 273.2 K in a hydrate form which is close to the Department of Energy volumetric target for methane storage. Dry water is a silica-stabilized free-flowing powder (95% wt water), and fast methane uptakes were observed (90% saturation uptake in 160 min with no mixing) as a result of the relatively large surface-to-volume ratio of this material.

A method for greatly accelerating the storage of gases such as hydrogen in clathrates by supporting the clathrate phase on a highly macroporous emulsion-templated polymer is presented. The gravimetric penalty is low due to the low bulk density of the support, no mechanical mixing is required, and the system is fully recyclable over multiple charge/ discharge cycles.

Fluorimetric studies on progesterone-induced [Ca(2+)](i) signalling in mammalian spermatozoa show both the well-characterised [Ca(2+)](i) transient and a subsequent sustained phase. However, the sustained phase is thought to reflect release of the fluorochrome during the acrosome reaction and has not been subject to critical investigation. We have used single-cell imaging of [Ca(2+)](i) to analyse the progesterone-induced [Ca(2+)](i) response in large numbers (>2000) of capacitated, human spermatozoa. In 70% of cells, treatment with progesterone induced a transient increase, which typically peaked within 1 min and decayed with a similar time course. Upon rapid application of progesterone this response peaked within 5-20 s. In 35% of progesterone-treated spermatozoa a sustained elevation of [Ca(2+)](i) occurred, which became discernible during the falling phase of the transient response and persisted for at least 20 min. Both [Ca(2+)](i) responses were localised to the postacrosomal region. Averaging of large numbers of single cell responses generated traces similar to those seen in fluorimetric studies. Although the sustained response was strongly associated with the initial, transient response, a few spermatozoa generated sustained responses that were not preceded by a significant transient response (5% of cells). It is concluded that a genuine biphasic [Ca(2+)](i) signal is activated by progesterone and that the sustained response is a discrete signalling event with biological significance.

Poly(vinyl acetate) (PVAc) is an inexpensive, high-tonnage bulk commodity polymer which, unlike most vinyl polymers, is moderately biodegradable. PVAc has been shown to exhibit anomalously high solubility in CO2 with respect to other vinyl hydrocarbon polymers. Understanding the phase behavior of PVAc in CO2 and its variation with structure is very important for its potential application as suitable surfactant, ligand, or phase transfer agent in a CO2 solvent process. In this article, PVAc has been fractionated using a supercritical fluid extraction method (SCFE) to provide low molecular weight fractions with narrow polydispersity. The phase behavior of hydroxyl terminated poly(vinyl acetate)s (PVAc-OH) were determined by a high throughput gravimetric extraction (HTGE) screening method and a cloud-point pressure method using a variable volume view cell (VVVC). The solubility of PVAc in CO2 strongly depends on the molecular weight. Oligomer PVAc-OH (M w < 3000 g·mol−1) is soluble in CO2 at low pressures but decreases in solubility with increasing molecular weight. End-group modification of oligomer PVAc-OH alters the phase behavior of the oligomers.