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Abstract: The hydrostatic pressure response of T C of the bisdiselenazolyl radical ferromagnet 1 up to 5GPa was investigated by AC magnetic susceptibility measurements using a SQUID magnetometer and a miniature diamond anvil cell. It was found that the ambient pressure value of T C =17K could be raised to 21K at a pressure of 0.9GPa. The experimental technique is described in detail and the pressure response is compared to that observed in related systems. [Copyright &y& Elsevier]

Purpose: The aim of this study was to show the results of computed tomography (CT)-based dosimetry of intracavitary brachytherapy for cervical cancer.Materials and Methods: A total of 20 patients with cervical cancer underwent intracavitary brachytherapy with external beam radiation therapy. The prescribed dose of brachytherapy was 6 Gy per fraction to point A. In every fraction a CT scan was performed after applicator insertion and three-dimensional (3D) dosimetry was done. The tumor dose was evaluated using D90 (the minimum dose delivered to 90% of the volume), and the doses of risk organs were evaluated using D2cc (the minimum dose in the most irradiated 2 cm3 of the volume).Results: The mean D90 for the clinical target volume (CTV) was 7.0 Gy (range 4.8-9.8 Gy). There was a negative correlation between the volume and the D90 for the CTV. The mean D2cc doses for the rectum and bladder were 6.0 Gy (range 3.9-9.0 Gy) and 6.5 Gy 5 Gy 2.9-9.0 Gy), respectively.Conclusion: CT-based 3D dosimetry of intracavitary brachytherapy for cervical cancer was useful for evaluating the doses of the CTV and the organs at risk. In cases with a large CTV, CTV D90 was often lower than the point A dose, and modulation of the prescribed dose might have to be considered. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic property and intraparticle structure of the γ phase of Fe2O3 (maghemite) nanoparticles with a diameter (D) of 5.1±0.5nm were investigated through AC and DC magnetic measurements and powder X-ray diffraction (XRD) measurements at pressures (P) up to 27.7kbar. Maghemite originally exhibits ferrimagnetic ordering below 918K, and has an inverse-spinel structure with vacancies. Maghemite nanoparticles studied here consist of a core with structural periodicity and a disordered shell without the periodicity, and core shows superparamagnetism. The DC and AC susceptibilities reveal that the anisotropy energy barrier (ΔE/k B) and the effective value of the core moment decrease against the initial pressure (P≤3.8kbar), recovering at P≥3.8kbar. The change of ΔE/k B with P is qualitatively identical with that of the core moment, suggesting a down-and-up fluctuation of the number of Fe3+ ions constituting the core at the pressure threshold of about 4kbar. This phenomenon was confirmed by the analysis of the XRD measurement using Scherrer’s formula. The core volume decreased for P≤2.5kbar, whereas at higher pressure the core was restructured. For 2.5≤P≤10.7kbar, the volume shrinkage of particle hardly occurs. There, ΔE/k B is approximately proportional to the volume associated to the ordered fraction of the nanoparticles as seen from XRD, V core. From this dependence it is possible to separate the core/shell contribution to ΔE/k B and estimate core and surface anisotropy constants. As for the structural experiments, similar experimental data have been obtained for D=12.8±3.2nm as well. [Copyright &y& Elsevier]

We have revealed that the isothermal magnetization M of the genuine organic crystalline dupeyredioxyl (N,N′-dioxy-1,3,5,7-tetramethyl-2,6-diazaadamantane; Tc(0)=1.48 K) observed below 10 K converges on the S=1 Brillouin function B1((H+λM)/kBT) with λ=2.4±0.2 or 2zJ/kB=3.6±0.3 K, where J and z are, respectively, the averaged exchange interactions and coordination numbers for the S=1 spin system. This fact suggests that S=1 is constructed within a molecule via a strong ferromagnetic coupling between two S=1/2 spins on each of the two NO moieties. The modified notation of the Rushbrooke and Wood theory, Tc=2AzJS(S+1)/kB (A=0.23±0.02 for the three-dimensional Heisenberg systems), is found to quantitatively hold not only for this S=1 spin system but also for other S=1/2 ferromagnets β-phase p-NPNN (2zJ/kB=3.6 K) and 2,5-DFPNN (2zJ/kB=2.8 K). Pressure effects of this compound have been studied under the hydrostatic pressure (P) up to 15 kbar. Tc(P) is revealed to show a negative pressure effect with the initial gradient a=d(Tc(P))/dP=−0.047 kbar−1, nearly the same value for other organic ferromagnets as β-phase p-NPNN (−0.048 kbar−1) and p-Cl-TEMPO radical (−0.03 kbar−1), in contrast to the positive pressure effect for genuine antiferromagnets such as TANOL (a=+0.15 kbar−1). Microscopically, different from the above two ferromagnets, the pressure-induced destruction of the orthogonality of molecular orbitals associated with the two NO moieties plays an effective role in reducing the intramolecular ferromagnetic interaction J0. The possible weaker intermolecular interactions other than J0 and J are also expected to be more susceptible to the stress of pressure to result in the reduction of their values perhaps even changing their sign, just as in the case of β-phase NPNN or p-Cl-TEMPO. [Copyright &y& Elsevier]

Hepatocytes isolated from F344 rats were transplanted into the spleens of congenic Nagase analbuminemic rats (NARs). The morphology and function of the transplanted hepatocytes were investigated after 18 months. The hepatocytes had formed nodules that occupied approximately 35% of the area of the splenic parenchyma on microscopic examination. Ultrastructural examination demonstrated that the organelles of the transplanted cells were indistinguishable from those of normal hepatocytes. The serum albumin level in NARs at 18 months after intrasplenic transplantation (HCTx) was about 3.6 % of that in normal rats. We confirmed that the hepatocytes in the spleen produced albumin and increased the serum albumin level in NARs with HCTx. The NAR model demonstrates the effect of HCTx and prolonged changes in the morphology of the hepatized spleen. [ABSTRACT FROM AUTHOR]