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T Miyanaga

Publications and source records attributed to T Miyanaga.

At least 19 recordsLinked to original sources
PubMed2003

Magnetic X-ray absorption fine structure for Ni-Mn alloys.

Magnetic X-ray absorption fine-structure (XAFS) spectra have been measured for Ni-Mn alloys. The magnetic XAFS in the near-edge region (X-ray absorption near-edge structure, XANES) and X-ray magnetic circular dichroism (XMCD) of the Mn and Ni K-edge for Ni(1-x)Mn(x) (x = 0.25, 0.24 and 0.20) show that (i) the local magnetic structure around the Mn atom is quite different from that around the Ni atom, and (ii) the peak intensity in the magnetic XANES of the Mn K-edge depends on the magnetization of the sample in contrast to the Ni K-edge. The Mn K-edge magnetic EXAFS (extended XAFS) for Ni(0.76)Mn(0.24) is also measured. The second and fourth peaks in the Fourier transform are observed to be enhanced in comparison with the non-magnetic EXAFS, indicating that the second- and fourth-shell Ni atoms are replaced by Mn atoms due to heat treatment (atomic ordering). Semi-relativistic theoretical calculation explains the observed magnetic EXAFS.

Journal Article↗
PubMed2001

Local structure of silver clusters in the channels of zeolite 4A.

The Ag K-edge EXAFS measurements have been carried out at 50 K for fully Ag+-exchanged zeolite 4A (Ag-4A) dehydrated at different temperatures under vacuum. In the Fourier transforms of the EXAFS oscillation the two distinct peaks appear around 2.2 A and 3.0 A, and a shoulder around 2.8 A. The structural parameters (distance, coordination number and root mean square displacement) were derived by a three-shell (two Ag-O contacts and Ag-Ag contact) curve-fitting analysis. It is found that a silver cluster is formed with Ag-Ag distance 2.82+/-0.02 A and coordination number 4.9+/-0.2. When the silver cluster is formed 6 Ag0 atoms and 8 Ag+ ions are arranged in a cubic closed-packed manner in the cage of the Ag-4A zeolite. The 8 Ag+ ions and 6 Ag0 atoms are confined in the framework of oxygens at distances of 2.28+/-0.02 and 2.88+/-0.02 A, respectively.

Journal Article↗
PubMed2001

Determination of dissociation energy for ligand exchange reaction from EXAFS.

EXAFS (extended X-ray absorption fine structure) experiments were performed at several different temperatures for a series of 3d transition metal ions (Cr3+, Fe3+, Fe2+, Ni2+, Co2+, Zn2+) in aqueous solutions. Anharmonic EXAFS analyses, which include up to third order cumulant, were carried out to study on the metal-oxygen bonding potential. According to the model in which the dissociation process is dominant for the ligand-water exchange reaction, the dissociation energy has been first evaluated from EXAFS in solution phase.

Journal Article↗
PubMed2000

Path-integral approach to Debye-Waller factors in EXAFS, EELS and XPD for cubic and quartic anharmonic potentials.

In this paper thermal effects in extended X-ray absorption fine structure (EXAFS) and X-ray photoelectron diffraction (XPD) due to atomic vibration in cubic and quartic potentials are studied by use of Feynman's path-integral approach. This approach can be applied to strongly anharmonic systems where the cumulant analyses break down. It is closely related to the well known classical approach which is only valid at high temperature. The phase of the thermal factor plays an important role both in EXAFS and XPD analyses for the asymmetric potential with strong anharmonicity. At low temperature the cumulant expansion up to the second order for the thermal damping function agrees well with the self-consistent result, but up to higher orders should be taken into account for the phase function. At high temperature the result from self-consistent calculations shows the characteristic behaviour: the thermal damping function is negative in the high-k region for both strongly and weakly anharmonic systems. The cumulant approximation cannot reproduce this behaviour. For the strongly anharmonic systems the quantum result shows qualitatively different behaviour from the classical approximation at low temperature: the former does not show the negative values even in the high-k region, while the latter shows the phase inversion in the amplitude.

Journal Article↗
PubMed1998

[Intra-arterial injection therapy of mitoxantrone for locally advanced breast cancer].

Mitoxantrone (MIT) is a new anthraquinone anticancer agent. We treated 14 patients with locally advanced breast cancer, 3 of which were inflammatory breast cancers, by pre-operative arterial injection of MIT. The treatment protocol was MIT 12 mg/m2 injected into both the internal mammary and the subclavian arteries with oral administration of 5'-DFUR 1,200 mg/day for 20 days. After 2 courses, all tumors were decreased over 50% in size. Down-staging was obtained in all of 8 cases. Mastectomy could be carried out on all patients, without microscopically residual tumor cells. Preoperative arterial injection of MIT might be the treatment of choice for locally advanced breast cancer to perform down-staging, however the survival benefit has remained equivocal. These preliminary results are encouraging to further studies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Small cell carcinoma of the kidney: case report.

An 83-year-old female diagnosed with small cell carcinoma of the kidney is reported on. The clinical picture was similar to that seen with transitional cell carcinoma of the renal pelvis. A right nephroureterectomy was performed and a histological examination revealed similar morphological features to those of small cell carcinoma of the lung. Neuroendocrine differentiation was proven by a positive immunoreaction to neuron-specific enolase. A review of the literature indicated that in the urinary tract, most of the cases of small cell carcinoma occurred in the urinary bladder, with this case being the eleventh reported case of small cell carcinoma originating in the kidney. As with many of the other cases of small cell carcinoma of the urinary tract, this patient's tumor was associated with both adenomatous and squamous differentiation. The patient died 2 months after surgery, prior to any chemotherapy administration.

Aged↗
PubMed1996

The positive relationship between the expression of CD44 variant 6 and prognosis in colorectal cancer.

CD44 variant 6 (CD44 v6) is well known as a useful marker of tumor progression; however, its relationship to prognosis has not yet been elucidated. In this study, we investigated the expression of CD44 v6 in colorectal cancer to analyze its relationship to hepatic metastasis as well as to prognosis. Tumor tissues were obtained from 42 patients with colorectal cancer who underwent curative resection with follow-up periods ranging from 5.9 to 71.3 months. There were 21 patients (50%) whose tumors were positive for CD44 v6, with no significant difference between colon and rectal cancer. CD44 v6 staining was significantly related to Dukes' classification as well as to hepatic metastasis. The 5-year survival rate was significantly higher in patients with CD44 v6 negative cancer (84%) than in those with CD44 v6 positive cancer (31%). Thus, we concluded that CD44 v6 could be a reliable prognostic indicator, as well as a predictor of metastatic potential after curative surgery for colorectal cancer.

Biomarkers, Tumor↗
PubMed1996

Pyeloplasty in hydronephrosis: examination of surgical results from a morphologic point of view.

BACKGROUND: Dilatation of the upper urinary tract is the most common congenital urogenital anomaly. Pyeloplasty is the therapy of choice in those patients with significant obstruction of the ureteropelvic junction. There are not many reports concerning the operative long-term results from a morphologic point of view. Furthermore, little information is available about children with giant hydronephrosis treated without resection of the dilated renal pelvis. METHODS: Between 1973 and 1993, 231 children with 262 renal units (kidney, renal pelvis, ureter) were treated at our institution. Giant hydronephrosis was observed in 52 renal units. The clinical and follow-up data were obtained from the patients' records. The dilatation of the upper urinary tract, confirmed by means of intravenous pyelogram, was divided into 5 grades. RESULTS: In 215 renal units, reconstructive surgery was performed without reduction of the renal pelvis. Revision of the pyeloplasty was necessary in 5 of the 215 renal units. The dilatation of the upper urinary tract improved or remained stable in 99.4% of the renal units during the follow-up period of 4.8 years (range, 1 month to 21 years). CONCLUSION: Surgical reconstruction of the ureteropelvic junction obstruction is a safe and successful procedure. The excision of the dilated pelvis does not seem to be necessary, even in patients with giant hydronephrosis.

Child↗
PubMed1995

Comparison by carcinoembryonic antigen doubling time of hepatic injection and infusion for unresectable hepatic metastasis from colorectal cancer.

This study explored the efficacy of hepatic arterial therapy, comparing both injection and infusion of 5-fluorouracil (5-FU) in prolonging the survival of 92 patients with recurrent unresectable hepatic metastasis from colorectal cancer. With respect to pretreatment carcinoembryonic antigen doubling time (CEA-DT), 56 patients were treated with intra-arterial injection, and 36 with intra-arterial infusion. In 21 patients with a CEA-DT of less than 40 days, the cumulative survival of patients treated with arterial injection was significantly longer than that of patients treated with arterial infusion. In 45 patients with a CEA-DT of 40-80 days, the survival curves of patients did not differ from each other. Of the remaining 26 patients with a CEA-DT of more than 80 days, those treated using arterial infusion had an excellent prognosis, in contrast to those treated using arterial injection, with statistical significance. CEA-DT may be useful when choosing a chemotherapy regimen, and may help to accurately establish the prognosis of patients with unresectable hepatic metastasis from colorectal cancer.

Adult↗
PubMed1994

[Clinical study on the effect of intra-arterial injection of mitoxantrone-lipiodol emulsion for hepatocellular carcinoma].

To investigate the effect of intra-arterial injection of mitoxantrone emulsified with ethiodized oil, forty-eight patients with hepatocellular carcinoma were evaluated. After the treatment, ten of the patients underwent hepatectomy. In the thirty-eight unresected cases, there were 15 (39%) partial responses, which continued 1.2 to 11.8 months (mean, 5.8 months). The 1- and 2- year survival rates were 67% and 38%, respectively. The response rate was higher in cases with tumor under 5 cm in diameter. In the remaining 10 resected cases, the necrotic areas in main nodules ranged from 65% to 100% (mean, 85%). This treatment might be applied effectively to patients with small hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1994

[A case of renal pseudotumor caused by pyelonephritis].

A case of renal pseudotumor due to pyelonephritis is reported. A 70-year-old female was admitted to our hospital for the evaluation of right renal mass in pyelogram. She had had episodes of pyelonephritis many times. Computed tomography (CT) revealed poorly marginated low density mass that exhibits inhomogenous enhancement with contrast medium. Angiography showed an avascular mass. On magnetic resonance imaging (MRI), the mass was isointensity or slightly low intensity on T1 weighted scan, while it showed low intensity on T2 weighted scan. The patient died from small cell carcinoma in the lung two years later. Autopsy was performed and no malignancy was found in the kidney. MRI was useful to differentiate such inflammatory change from renal tumor, which is mostly high intensity on T2 weighted scan.

Aged↗