A metastable phase in thermal decomposition of Ca-deficient hydroxyapatite

We investigated the microstructural changes on an atomic length scale during thermal decomposition process of Ca-deficient hydroxyapatite (Ca-def HAp) by high-resolution transmission electron microscopy (HRTEM). Ca-def HAp was prepared by hydrolysis of -tricalcium phosphate. The Ca-def HAp had a whisker-like morphology 2–5 m in length and 0.1 m in diameter that was elongated along c-axis. Thicker planer defects parallel to the (100) plane of the HAp matrix were observed as precipitation in the sample annealed at 700 and 800 °C by HRTEM observation. Thickness of the precipitation was about 10 nm and the boundaries between the precipitation and HAp matrix was coincident. The periodicity in the precipitation was parallel to the (100) plane of the HAp matrix and measured to be 1.42 nm. Since the precipitation was observed only in the sample annealed at a narrow temperature range of 700–800 °C, it was regarded as a metastable phase formed on the thermal decomposition process. Absorption peaks in IR spectra of annealed Ca-def HAp containing the metastable phase appeared at 744 and 3538 cm^–1 due to non-stoichiometric HAp with high Ca/P molar ratio. Furthermore, the results of energy dispersive X-ray spectroscopy showed that the metastable phase had higher Ca/P molar ratio than that of the matrix and stoichiometric HAp. Therefore, the metastable phase could be identified as Ca-rich metastable phase. The presence of Ca-rich metastable phase was confirmed to be associated with the thermal decomposition process.     

Establishment of a series of alien monosomic addition lines of Japanese bunching onion (Allium fistulosum L.) with extra chromosomes from shallot (A. cepa L. aggregatum group)

We performed an oral tolerance test for potassium metabisulfite in 33 patients and discovered sulfite intolerance in 9. These 9 patients had rhinitis including 7 with asthma. Alcoholic beverages, especially champagne, were the triggering factors the most frequently found for respiratory manifestations. Alcoholic beverages triggered bronchial or nasal reactions in 7 patients out of 9 (rhinitis in 7, asthma in 2). As in a large number of published cases, sulfite intolerance was evidenced by respiratory manifestations in our patients. Exceptional anaphylactic reactions have also been reported. Respiratory intolerance to sulfites in uncommon. A nasal or bronchial reaction occurring within minutes following ingestion of alcoholic beverages is highly suggestive of sulfite intolerance as is the development of acute asthma after administration of sulfite-containing drugs. Diagnosis is confirmed by oral tolerance tests versus placebo. The only effective preventive measure is to eliminate food and drugs containing sulfites. Such measures are justified to prevent acute episodes of asthma.     

Three-dimensional reconstruction by scanning electron microscopy from serial epoxy resin semi-thin sections after ion-etching

Three-dimensional reconstruction was performed using scanning electron micrographs of serial semi-thin sections of Epon embedded specimens. Connective tissue in a rabbit ear chamber was fixed in glutaraldehyde and osmium tetroxide, and then embedded in Epon. One-microm-thick serial sections were cut with a diamond knife, mounted on glass slides and stained with toluidine blue. After observation with a light microscope, the sections were ion-etched with an ion-spatter coater. Following double staining with uranyl acetate and lead citrate, the consecutive sections were ion-coated with platinum. Each serial section was photographed with a scanning electron microscope. Profiles of a blood vessel and fibroblasts were digitized with a computer and computer reconstruction of the blood vessel was performed. Three-dimensional reconstructions showed that the newly formed blood vessel was a cylinder-like, bare endothelial tube with a rather smooth outer surface. Fibroblasts were situated around the endothelial tube. Several openings were found in the endothelial tube, suggesting the morphological feature of high permeability and fragility in newly formed blood vessels. The availability of three-dimensional reconstruction from scanning electron micrographs of serial semi-thin epoxy resin sections was discussed; structures of interest can be reconstructed (1) quickly and easily, (2) without skilful techniques, and (3) almost at the level of ultrastructure.     

Suppression of Cu agglomeration in the Cu/Ta/Si structure by capping layer

Cu/Ta/Si (100) structures deposited by the non-mass separated ion beam deposition system showed a slight resistivity increase at 650 °C due to a Cu agglomeration. To suppress the Cu agglomeration on the Ta layer, a capping layer was deposited on the Cu/Ta/Si structure using Ta or SiO₂ as a suppressor. In the case of the Ta suppressor, the agglomeration of Cu was observed between two distorted Ta films due to the difference in thermal expansion between the Cu filmand the Ta film at high temperature. On the other hand, the SiO₂ layer was found to be suitable as a suppressor, and the Cu agglomeration did not occur even after annealing at 650 °C by the suppression of the Cu diffusion.     

Development of a novel microbial sensor with baker's yeast cells for monitoring temperature control during cold food chain

A novel microbial sensor containing a commercial baker's yeast with a high freeze tolerance was developed for visibly detecting inappropriate temperature control of food. When the yeast cells fermented glucose, the resulting gas production triggered the microbial sensor. The biosensor was a simple, small bag containing a solution of yeast cells, yeast extract, glucose, and glycerol sealed up with multilayer transparent film with barriers against oxygen and humidity. Fine adjustment of gas productivity in the biosensor at low temperatures was achieved by changing either or both concentrations of glucose and yeast cells. Moreover, the amount of time that food was exposed to inappropriate temperatures could be deduced by the amount of gas produced in the biosensor. The biosensor was stable without any functional loss for up to 1 week in frozen storage. The biosensor could offer a useful tool for securing food safety by maintaining low-temperature control in every stage from farm to fork, including during transportation, in the store, and at home.     

Enhancing low-temperature energy harvesting by lead-free ferroelectric Ba(Zr0.1Ti0.9)O3

The energy-harvesting ability of the lead-free ferroelectric Ba(Zr,Ti)O₃ was investigated and greatly enhanced using the Kim novel electrothermodynamic cycle for low-temperature application. Ba(Zr,Ti)O₃ was synthesized with a Zr:Ti ratio of 10:90 (BZT10) by hot-press sintering, which exhibited a mix relaxor-ferroelectric behavior. For power generation using the Kim cycle with low and high temperatures of T_L = 25°C, T_H = 120°C, the most optimized temperature pattern occurred for a heating time of 12.5 s and a cooling time of 22.5 s. Under these conditions, the electric field increased during the novel isodisplacement process, and the displacement variation in the isoelectric step reached the highest value and maximized the BZT10 cycle loop area. Applying these conditions while lowering T_L to 20°C, an energy density N_D = 504 mJ/cm³ was achieved. This value is the highest obtained energy density in a practical test for lead-free ferroelectric bulk material in the BaTiO₃ family.