On the Internal Friction of Ferromagnetic Substances

In ferromagnetic substance, the origin of internal friction under low stress amplitude has been considered to be due to two kinds of eddy currents, the first named macroscopic eddy current was studied by Brown and its theoretically predicted contribution to internal friction was known to be consistent with the experimental data. But the second named microscopic eddy current has not yet been investigated except in demagnetized state. In this paper, the latter was calculated theoretically as a function of the magnetization and the results were compared with the experimental data obtained with the substances which have neglisibly small anisotropic energy. Two different theories were respectively developed under two assumptions on the generating mechanism of microscopic eddy current. The first theory which assumes that the microscopic eddy current is induced by the rotation of the spontaneous magnetization concludes that the relation between internal friction and the magnetization is given by a curve with a maximum starting from a finite value at demagnetized state, while the second assuming the displacement of the 180° magnetic domain boundary concludes that internal friction is proportional to the square of the magnetization. To confirm these theoretical results, following three series of measurements of internal friction were made using transversal vibration of about 500～1,000 cps. (1) The effect of superlattice formation on the internal friction of Ni_3Fe was observed and the results were well explained by considering both macro- and micro-scopic eddy currents. In this case, microscopic eddy current is considered to be induced by the rotation of the spontaneous magnetization. (2) Internal friction of the field-cooled Ni_3Fe was also explained by the microscopic eddy current due to the rotation of the spontaneous magnetization. (3) The behaviour of internal friction of 65-Permalloy showed remarkable difference from that of Ni_3Fe. It could be explained neither by considering the rotation of the spontaneous magnetization nor by considering the displacement of 180° domain boundaries, so that the other process must be introduced to explain the experimental facts. The internal friction of Perminvar shows intermediate character between Ni_3Fe and 65-Permalloy. It will be explained by considering both the rotation of the spontaneous magnetization and the other process which is responsible for the internal friction of 65-Permalloy

Anelastic Study on the Diffusion Coefficients of Alpha-Brass

The anelastic relaxation in alpha-brass was measured in the temperature range from about 20 to 400℃, and the chemical diffusion coefficient was calculated from these results by two different methods suggested by Le Claire and by Nowick. The comparison of diffusion coefficients thus obtained with those obtained conventionally gave a criticism of these methods. It was seen from the comparison that the modified Nowick\u27s formula showed the best agreement and that Le Claire\u27s formula would be improved if his calculation was extended to a more detailed model

Anelastic Measurement on the Recovery of Cold-Worked Aluminium

The change of internal friction accompanied by the recovery of cold-work in aluminium was measured and compared with those in other physical properties, namely, hardness and thermoelectric power. The results showed that (1) internal friction increases monotonously with cold-work ; (2) the values of internal friction and other properties decrease exponentially by annealing, the relaxation times and saturation values being functions of annealing temperatures ; (3) the internal friction changes remarkably by low temperature annealing, while other physical properties do not change. These results were explained from the concept that the internal friction is caused by the viscous behaviors of grain boundaries which consist of various kinds of lattice defects

mRNA detection of individual cells with the single cell nanoprobe method compared with in situ hybridization

<p>Abstract</p> <p>Background</p> <p>The localization of specific mRNA generates cell polarity by controlling the translation sites of specific proteins. Although most of these events depend on differences in gene expression, no method is available to examine time dependent gene expression of individual living cells. <it>In situ </it>hybridization (ISH) is a powerful and useful method for detecting the localization of mRNAs, but it does not allow a time dependent analysis of mRNA expression in single living cells because the cells have to be fixed for mRNA detection. To overcome these issues, the extraction of biomolecules such as mRNAs, proteins, and lipids from living cells should be performed without severe damage to the cells. In previous studies, we have reported a single cell nanoprobe (SCN) method to examine gene expression of individual living cells using atomic force microscopy (AFM) without killing the cells.</p> <p>Results</p> <p>In order to evaluate the SCN method, we compared the SCN method with <it>in situ </it>hybridization (ISH). First, we examined spatial β-actin mRNA expression in single living cells with the SCN method, and then the same cells were subjected to ISH for β-actin mRNA. In the SCN method, quantity of β-actin mRNA were analysed by quantitative PCR, and in ISH we used intensity of ISH as a parameter of concentration of β-actin mRNA. We showed that intensity of ISH is higher; quantity of β-actin mRNA detected by the SCN method increased more.</p> <p>Conclusion</p> <p>In this study, we compare the SCN method with the ISH. We examined β-actin mRNA expression in single cells using both methods. We picked up β-actin mRNA from several loci of a single living cell using an AFM nanoprobe, and identical cells were subjected to ISH. The results showed a good correlation between the SCN method and ISH. The SCN method is suitable and reliable to examine mRNAs at medium or higher expression level.</p

Laparoscopic cholecystectomy: report of 42 cases.

Our initial experience with laparoscopic cholecystectomy for cholecystitis and cholelithiasis was reviewed in 42 patients and the data were compared with those of 21 patients who underwent conventional open cholecystectomy previously. Only one patient required conversion to an open operation. Three of the 42 patients had minor complications without death in laparoscopic cholecystectomy. The mean time for the laparoscopic cholecystectomy was 100 +/- 40 min, as compared with 79 +/- 21 min for the open cholecystectomy. The average postoperative hospital stay was 11.4 +/- 7.1 days for the laparoscopic procedure and 35.5 +/- 15.4 days for the conventional procedure. The laparoscopic cholecystectomy offers the patients shortened hospitalization and lower complications and can replace the conventional open cholecystectomy in large degree, at least in the uncomplicated cases.</p

On the Change of Reversible Susceptibility of Ferromagnetic Substances Due to Tension

According to the internal stress theory on ferromagnetic substances given by Kersten and Doring, the authors have calculated the reversible susceptibility as a function of magnetization under various applied tensions. Theoretical reversible susceptibility thus obtained is constant at early stage of magnetization and decreases rapidly just before the magnetic saturation. But, if the magnitude of internal stress is larger than that applied, it has a maximum before sudden decrease, which occurs near magnetic saturation. These theoretical results explain experimental data qualitatively, but some quantitative differences are found between these

Epstein-Barr Virus-associated Post-Transplant Lymphoproliferative Disorders presented as Interstitial Pneumonia; Successful Recovery with Rituximab

We describe a patient that developed Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorders (PTLD), which presented as interstitial pneumonia. He had received allogeneic bone marrow transplantation for the treatment of acute myeloid leukemia 17 months before, when he developed hypoxemia requiring emergent admission. Chest computed tomography revealed pulmonary interstitial shadows, but neither hepatomegaly nor lymphadenopathy were detected. Bronchoscopy with lung biopsy revealed a lymphomatous proliferation of EBV-infected B cells. The interstitial pneumonia rapidly deteriorated, but improved dramatically after treatment with anti-CD20 monoclonal antibody (rituximab). This is the first report of a patient with lung EBV-PTLD that presented as interstitial pneumonia and was successfully treated with rituximab