A second-order crystalline phase transition occurs between 120 and 5 K in trisodium lanthanide tris(oxydiacetate) ditsodium perchlorate) hexahydrate single crystals, Na3Ln(C4H405)3.2NaC104*6H20.Results from optical, circular dichroism and electron paramagnetic resonance spectroscopy are used to define the low-temperature space group. The transition is from the room-temperature space group R32 to P3121 or its mirror image P3221. It lowers the site symmetry of the lanthanide from 0 3 to C2 and results in movement of a sodium ion off a three-fold axis.Compounds of the formula Na3Ln(C4H405)3.2NaClO4-6H20, the lanthanide tris oxydiacetates (LnODA), provide an opportunity to study the circular dichroism spectra of trivalent lanthanide ions in the solid state with achiral ligands. These compounds have several advantages for such a study. They are easily grown out of aqueous solution at room temperature, they are very stable in air and, at room temperature, the lanthanide site symmetry, D3, is relatively high. This latter point makes crystal-field assignments easier than if no degeneracy existed in the electronic states. In addition, having the ions in the solid state allows spectra to be recorded at temperatures below room temperature where optical absorptions are sharper and electronic (and vibronic) hot bands are depopulated. These low-temperature spectra, down to 5 K, are essential if the details of the crystal-field energies are to be found.In the course of recent studieslP3 it was found that the spectroscopic behaviour of these materials at temperatures of 80 K or less could not be explained on the basis of the room-temperature crystal structure. If the electronic and magnetic properties of these crystals are to be correctly interpreted, knowledge of the low-temperature structure is necessary. This report presents the results of optical, circular dichroism and electron paramagnetic resonance studies on a series of LnODA with the aim of eliciting information on the low-temperature space group and proposing reasons for the phase transition. In principle the structure could be determined from X-ray diffraction data taken at some temperature below the phase transition. However, our data, given below, indicate the phase transition is second-order and is only "complete" at temperatures well below 80 K. Determining crystal structures at these temperatures is a non-trivial process and equipment for that experiment is not
Anisakis is a parasite that is found in many marine products and can cause anisakiasis when present in fish consumed raw. The most common way to prevent anisakiasis is to freeze the fish, but this causes a noticeable decrease in the quality of the fish when eaten as sashimi. Although no practical method of killing anisakis other than freezing has been found, we have now succeeded in inactivating anisakis inside the fish meat by repeatedly and instantaneously applying electric current to the fish meat using pulsed power technology. The fish meat was placed in buffer saltwater, and pulsed power was applied multiple times. The immobilization rate was highest when the buffer saltwater was 5 mS/cm. The immobility ratio increased as the number of shots increased. Sensory evaluation of the fish meat after the pulse treatment confirmed that it retained its quality as sashimi. Breaking tests and color measurements were also conducted. We believe that this pulsed power treatment is a useful alternative to freezing as a method for killing anisakis.
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