Synthesis of TiO(2) nanocrystals controlled by means of the size of magnetic elements and the level of doping with them.

TiO(2) nanocrystals were synthesized by a hydrolysis method combined with a thermal treatment. TiO(2) nanocrystals with rutile and anatase structure were selectively synthesized by controlling the pH level in the precursor solution, and the crystallite size was controlled by changing the reaction temperature. Moreover, Co-doped TiO(2) nanocrystals with rutile structure were also synthesized by means of the addition of Co to the precursor solution. Secondary phases such as Co precipitates and Co oxide were not present in the sample tested, with [Co]<10 mol%. With an increase in the Co doping level, the E(g)-phonon signal at 447 cm(-1) was broadened and shifted to a lower frequency, indicating the incorporation of Co into the rutile TiO(2) host lattice and lattice expansion. Optical absorption spectra showed that the absorption edge at ∼3.0 eV corresponded to the band gap of rutile TiO(2) and shifted to the lower energy side upon Co doping. These results indicated the possibility of band gap engineering of rutile TiO(2) via Co doping. On the other hand, the charge transfer gap between O 2p and Co 3d orbitals was also observed for samples with Co, suggesting the possibility of photo-induced magnetism in rutile TiO(2) nanocrystals, obtained by visible light irradiation.

Structural and electronic properties of ZnO polycrystals doped with Co.

Zn(1-x)Co(x)O samples were prepared by a standard solid-state reaction method. Zn(1-x)Co(x)O crystals in the wurtzite structure were obtained with a Co composition of up to 22.1%. The a- and c-axis lengths increased and decreased, respectively, with an increase in Co composition. Raman spectra showed systematic broadening of the E(2) (high) phonon mode associated with the increase in Co composition, and electronic transitions of Co in the oxygen tetrahedron were observed in optical absorption measurement. These results indicated systematic substitution of Co into the Zn sites. Furthermore, an additional broad absorption band at 2.4-3.3 eV corresponding to the charge transfer (CT) process [Formula: see text] was also observed. The Raman spectra showed strong enhancement of the LO phonon due to a resonant Raman process induced with the coupling of the LO phonon and a photo-excited carriers mediated CT gap. These results suggest the possibility of carrier-induced ferromagnetism based on double exchange interaction in Zn(1-x)Co(x)O by visible light irradiation.

Spin-phonon coupling in multiferroic YbMnO(3) studied by Raman scattering.

Hexagonal YbMnO(3) bulk polycrystals were prepared and studied by Raman scattering in the temperature range of 15-300 K. A total of 15 phonon modes of A(1), E(1) and E(2) type were identified. Some E(2) phonon modes showed anomalous temperature variations in frequency at T(N)∼80 K, suggesting a coupling between the spin and phonon systems below T(N). As another evidence of spin-phonon coupling, softening of an A(1)-phonon mode for the O-Mn vibration was observed at ∼T(N). Substitution of Mn by Al suggests this view.

Raman scattering study of multiferroic Ho(3)Fe(5)O(12) thin films.

Ho(3)Fe(5)O(12) crystallizes in a body-centered cubic lattice and shows no ferroelectricity because of its highly symmetric (centrosymmetric) crystal structure. However, in heteroepitaxially grown thin films, Ho(3)Fe(5)O(12) may exhibit ferroelectricity because of lattice strains induced by the substrate. In this work, heteroepitaxial films of Ho(3)Fe(5)O(12) were grown with different thicknesses of 50-160 nm and studied by x-ray diffraction and Raman scattering. The results were compared with those of bulk polycrystals to characterize residual strains. At room temperature, Raman spectra of films revealed a phonon frequency shift from those of bulk samples, showing lattice distortion. There was a difference in the lattice distortion scheme between the thinner and thicker films. Results of x-ray diffraction were well correlated with the Raman data. Raman measurements at 300-800 K showed the existence of lattice strain up to ∼650 K. This suggests a remanent-polarization character of Ho(3)Fe(5)O(12) films up to this temperature. Closeness between the magnetic ordering temperature T(N) = 567 K and T(C)∼650 K may bring us the ideal multiferroic material with an enhanced magnetoelectric effect at room temperature.

Clinical outcome after endoscopic mucosal resection for esophageal squamous cell carcinoma invading the muscularis mucosae--a multicenter retrospective cohort study.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) is now commonly indicated for esophageal squamous cell carcinoma (ESCC) within the lamina propria mucosa. However, EMR for ESCC that has invaded the muscularis mucosa is controversial because the risk of lymph node metastasis is not negligible. We conducted a multicenter retrospective cohort study to investigate the incidence of lymph node metastasis and survival after EMR for ESCC invading the muscularis mucosa. PATIENTS AND METHODS: A total of 104 patients with 111 lesions invading the muscularis mucosa, were retrospectively studied at eight institutes. No patients exhibited evidence of metastasis of lymph nodes or distant organs prior to EMR. Overall and cause-specific survival rates were calculated from the date of EMR to the date of death or the most recent follow-up visit. Survival curves were plotted according to the Kaplan-Meier method. RESULTS: In total, 86 patients (82.7%) who did not receive further treatment such as chemotherapy, irradiation therapy, chemoradiotherapy, or esophagectomy after EMR were followed up. Only two patients (1.9%) developed lymph node metastasis after EMR. With a median follow-up period of 43 months (range, 8-134 months), overall and cause-specific survival rates at 5 years after EMR were 79.5% and 95.0%, respectively. CONCLUSIONS: EMR for ESCC that invades the muscularis mucosa has curative potential as a minimally invasive treatment option.

Structural properties of nanometre-sized ZnO crystals doped with Co.

Nanometre-sized ZnO crystals doped with Co were synthesized by a co-precipitation method combined with a thermal treatment. By changing the reaction temperature, we can control the crystallite size from roughly 10 nm particles to 20 nm × 200 nm nm rods grown along the hexagonal c-direction. X-ray diffraction and Raman scattering showed growth of high-quality wurtzite ZnO crystals incorporating Co systematically in the ZnO host lattice in the tested range of [Co]<3.0 mol%. Electronic transitions of Co in the oxygen tetrahedron were also observed in optical absorption, giving supporting evidence for systematic substitution of Co into the Zn site.

[All-trans retinoic acid combined with low-dose cytosine arabinoside treatment for acute myelogenous leukemia with trilineage myelodysplasia--a case report].

AML with trilineage myelodysplasia (AML/TMDS) is recognized as having of poor prognosis due to its resistance to chemotherapy in comparison with de novo AML. An AML/TMDS patient who failed to respond to ordinary induction therapy achieved complete remission with combination therapy consisting of all-trans retinoic acid (ATRA) and low-dose Ara-C. No serious toxicity was observed. ATRA combined with low-dose Ara-C could be an alternative treatment for this kind of patient.

Acute lymphoblastic leukemia accompanied by chromosomal abnormality of translocation (12;17).

This report concerns a female patient with B-precursor acute lymphoblastic leukemia with concomitant expression of CD13 and CD33. A rare chromosomal abnormality, t(2;17)(p13:q21), was detected in 70% of metaphases analyzed. A new subgroup of acute leukemia is proposed, consisting of our case and 12 reported cases with similar chromosomal abnormalities. This subgroup has a poor prognosis and a high incidence of biphenotypic characteristics.