Hidekazu Tanaka

We report on the electrical modulation of double exchange ferromagnetism at room temperature in hole-doped manganites of a metal oxide p-n junction. In this (La0.9Ba0.1)MnO(3)/Nb doped SrTiO3 p-n junction, the temperature dependence of the junction resistance shows a metal-insulator transition whose temperature, corresponding to that of ferromagnetic transition, is hugely modulated from 290 to 340 K by a bias voltage increasing from +1.0 to +1.8 V. The magnetoresistance can also be modulated ele

Two-terminal multistate memory elements based on VO(2)/TiO(2) thin film microcantilevers are reported. Volatile and non-volatile multiple resistance states are programmed by current pulses at temperatures within the hysteretic region of the metal-insulator transition of VO(2). The memory mechanism is based on current-induced creation of metallic clusters by self-heating of micrometric suspended regions and resistive reading via percolation.

Electrochemical aptasensors involved in chemical labeling are often single-use and sensitivity-limited because the probes are commonly single-point labeled and irreversible. In this work, the specific coordination between Zr⁴⁺ and phosphate group (-PO₄^3-) was employed to construct a new aptasensor that is highly sensitive and reusable, using Ochratoxin A (OTA) as the test model. The OTA binding aptamer (OBA) was hybridized with the thiolated supporting sequence (

Colloidal calcium hydroxyapatite (CaHAP) particles synthesized by a wet method and calcined at different temperatures up to 900 °C have been characterized by various means. The adsorption species and sites on the CaHAP surface for pyridine, n-butylamine and acetic acid were clarified by FTIR and TPD. These molecules were shown to be adsorbed by hydrogen-bonding to the surface P–OH groups. The surface P–OH groups of CaHAP were removed by outgassing above 600 °C to produce surface P–O–P groups. Th

Synthetic colloidal calcium hydroxyapatites (Ca10(PO4)6(OH)2, CaHAP), treated with hexyl, octyl, and decyl phosphates in acetone−water solutions, were characterized by various means. XRD patterns of the modified materials showed a strong peak and two weak ones besides the peaks due to CaHAP. The d value of these three additional peaks linearly increased with an increase in the carbon number of the phosphates. Upon increasing the concentration of the phosphates in the treating solution, these pea

Synthetic calcium hydroxyapatite, Ca10(PO4)6(OH)2 (CaHap), prepared by a wet method was evacuated at various temperatures up to 900°C and the influence of thermal treatment on the structure of this material was investigated by FTIR, determination of concentration of surface P–OH groups, adsorption of H2O and heat of immersion in water. The number of surface P–OH groups was 2.6 groups nm−2 and the ionic ratio of surface HPO42− to H2PO4− was 31:69. The surface P–OH groups were essentially dehydrox