A natural Mg-Al-Fe spinel from the Balmuccia peridotite (Italian Western Alps) was annealed at T between 650 and 1150°C, under controlled oxygen activity, and quenched in H2O. Twenty-three cation distributions were calculated from XRD structural refinements in tandem with microprobe analysis, and verified by Mössbauer spectroscopy in the case of unheated samples.

Unheated crystals showed essentially ordered distribution of Fe3+ in octahedral and Fe2+ in tetrahedral sites, the only intracrystalline disorder being represented by ∼0.12 atoms per formula unit of [4]Al and [6]Mg. Thermal runs and quenching maintained substantially ordered distribution of Fe2+ and Fe3+ up to ∼990°C and produced continuous [4]Mg-[6]Al exchange. Between 990 and 1150°C, the previous order of Fe2+-Fe3+ appeared to change slightly, [6]Fe2+ reaching ∼0.04 afu and [6]Mg ≅ [4]Al ≅ 0.24 afu at the highest T. After quenching from this temperature, Fe2+ still resided mainly in the T site. Some previously heated crystals underwent reordering on lowering of the temperature.

Experimental data, integrated with existing literature, enabled cation-oxygen distance in this structure to be improved. Results from annealed samples allowed the formulation of an experimental thermometric function based on Mg-Al intracrystalline disorder.

The ferroelectric liquid crystal material [4-[(4-methyloxyfenyl) carbonyloxyl] bifenyl-4′-yl]-(S)-2-methylbutoxypropionate containing a lateral methyl group on the aromatic ring of the alkoxybenzoate unit and two chiral carbons has been investigated by X-ray powder diffraction analysis at the 28 °C–105 °C temperature range. On cooling through the SmC temperature range, the layer spacing decreases from 28.3 to 27.7 Å with a small variation of average intermolecular distances. Lattice parameters of tetragonal and monoclinic crystalline phases occurring at lower temperatures have been determined.

The technique of cryoenzymology has been applied to the hammerhead ribozyme in an attempt to uncover a structural rearrangement step prior to cleavage. Several cryosolvents were tested and 40% (v/v) methanol in water was found to perturb the system only minimally. This solvent allowed the measurement of ribozyme activity between 30 and −33°C. Eyring plots are linear down to −27°C, but a drastic reduction in activity occurs below this temperature. However, even at extremely low temperatures, the rate is still quite pH dependent, suggesting that the chemical step rather than a structural rearrangement is still rate-limiting. The nonlinearity of the Eyring plot may be the result of a transition to a cold-denatured state or a glassed state.

Eggs of the stoneflies Diura bicaudata and Arcynopteryx compacta, occurring in the middle-alpine vegetation belt, andDinocras cephalotes not recorded above the sub-alpine, reacted differently to the same temperatures. Those of D. bicaudata and A. compacta had a diapause during the winter. D. cephalotes eggs went into a stage of quiescence when the water temperature was lowered from 16° C to 8° C or below. They remained alive in this stage for about a year, but this quiescence could be broken at anay time when the eggs were transferred to 16 and 20° C.Freezing at -6° C followed by an increase in the water temperature led to a break in the diapause of A. compacta eggs after five months, but not of D. bicaudata eggs.Eggs of D. bicaudata began to hatch after nine months independently of previous freezing followed by an increase inwater temperature. Eggs of D. bicaudata held at a constant temperature of 1.5° C also began to hatch at the same timeas those kept at 8° or 16° C. However, the point of 50 % hatching was much delayed at 1.5° C.The egg diapause of A. compacta and D. bicaudata is an adaptation to areas with a severe climate typified by long cold winters and short summers. The quiescence period of D. cephalotes eggs enables the species to survive outside its normal distribution area.