ASCA Observations of Two Ultra-Luminous Compact X-Ray Sources in the Edge-on Spiral Galaxy NGC 4565

The edge-on spiral galaxy NGC 4565 was observed for $\sim$ 35 ks with ASCA in the 0.5-10 keV energy band. The X-ray emission was dominated by two bright sources, which can be identified with two point-like X-ray sources seen in the ROSAT HRI image. The observed 0.5-10 keV fluxes of these sources, $1.7 \times 10^{-12} erg/s cm^{-2}$ and $0.7 \times 10^{-12}erg/s cm^{-2}$, %$1.66 \times 10^{-12} erg/s cm^{-2}$ %$0.66 \times 10^{-12} erg/s cm^{-2}$ imply bolometric luminosities of $1.0\times 10^{40} erg/s$ and $4 \times 10^{39} erg/s$, respectively. They exhibit similar spectra, which can be explained by emission from optically thick accretion disks with the inner disk temperature of 1.4-1.6 keV. One of them, coincident in position with the nucleus, shows too low absorption to be the active nucleus seen through the galaxy disk. Their spectra and high luminosities suggest that they are both mass accreting black hole binaries. However the black-hole mass required by the Eddington limit is rather high ($\geq 50 M_{\odot}$), and the observed disk temperature is too high to be compatible with the high black-hole mass. Several attempts are made to solve these problesms.Comment: 20page

Effects of Stress History and Corrosive Environment on Fatigue Crack Propagation

The effects of stress history and corrosive environment on fatigue crack propagation of a mild steel are discussed under the constant and the variable stress amplitude, and the corrosion fatigue strength under service load is made clear as follows ; The crack initiation of corrosion fatigue is very early but the crack rate in saline and in water becomes smaller than that in air from a certain value of crack depth. This may be due to the wedge action of metal oxide in cracks. In hydrochloric acid the decrease of the crack rate is not observed because of the dissolution of metal oxide. Under high-low two-step stress history, both in air and in saline the crack propagation is delayed for a considerable period after the stress change and the subsequent crack rate is nearly equal to the expected one for the lower stress. Under continuously decreasing stress history as well, both in air and in saline the crack rate becomes smaller than the expected one based on the linear cumulative damage hypothesis. This is due to the deceleration effect corresponding to the delay in crack propagation under high-low stresses. On the other hand, under low-high two-step stress history, the crack rate in air after the stress change is the same as expected, while the rate in saline is greater for a while after the stress change due to the balance of the metal oxide produced on the crack wall and the opening of the crack, and then gradually decreases to the expected one. The acceleration effect of the crack propagation, however, tends to diminish at a smaller increasing rate of the stress amplitude under continuously increasing stress history. ∫(dn/N) under the various stress patterns may be estimated by considering the acceleration effect and deceleration effect. For example, ∫(dn/N)≅l is concluded in saline under two-stress repeated block history and under stress varying up and down in a short period because of the mutual offset of the acceleration effect and the deceleration one. Since the life of smooth specimens in corrosive environments is wholly occupied by crack propagation, the same argument for notched specimens mentioned above may be applicable to the corrosion fatigue of smooth specimens under various stress histories

Creep Deformation Characteristics of Weathered Granite

Creep deformation characteristics of weathered granite were studied. While displacement of a structure on foundation rock is the main concern of foundation designers, the mechanical and especially the time dependent properties of weathered granite, which is being used recently as a foundation rock in Japan, have not been investigated so much. The test results show that the behavior of soft rock is very similar to that of soil. The time dependent deformation in soft rock can be predicted by a simple stress-strain-time function or rheological models. The time to failure under a sustained creep load was also discussed in relation to the strength of weathered granite

Strength Characteristics of Weathered Granite

Weathered granite, which widely distributed in Japan, was tested by a triaxial testing apparatus to investigate its mechanical properties in the consolidated-undrained condition. This rock, classified as a soft rock, causes much trouble in the construction of civil engineering structures. However, its mechanical behavior has not been studied enough to understand the strength characteristics. In this paper, it was found that the general behavior of the weathered granite was very similar to that of clay. The comparison between these materials has been discussed. The strength parameters were obtained from yield points which were defined by two different methods. The physical meanings of these yield points were also discussed

Training to Improve Teaching Skill on Measurement and Control Technology Education for Industrial Education Teachers at Technical High Schools

Industrial high schools need to incorporate new educational content and methods to respond to changes in industrial structure and progress in science and technology. Because the expertise and skills required in the industry are becoming more sophisticated, it is also necessary to review the training of teachers. Therefore, in this study, we examined training for teachers at technical high schools who were aiming to acquire the basic expertise and skills related to the “measurement and control” used in the industry. In addition, the evaluation was conducted by questionnaire before and after the training. The evaluation showed that teachers were interested in the “measurement and control” technology education provided by this training, and many commented that they wanted to use it in their classes. From these results, the effectiveness of the training content and the teaching materials were confirmed

CLINICOPATHOLOGICAL STUDY OF CEREBRAL SUBCORTICAL CAVERNOUS ANGIOMA AS EPILEPTOGENIC FOCUS

The authors conducted a comparative histological study of two groups of patients with cerebral subcortical cavernous angioma. One group was composed of 5 asymptomatic cases detected accidentally. The other group was composed of 4 patients presenting as epilepsy. The results obtained may be summarized as follows ; 1) Hemosiderin deposit and gliosis were seen in all cases examined ; 2) Granulomatous change was a histological finding associated with epileptogenesis ; 3) The histological changes, starting with proliferation of collagen fibers and leading to hyaline degeneration, calcification, and then hemangioma calcificans, seem to represent a course of spontaneous healing, when viewed from epileptogenesis

Distorted antibody repertoire developed in the absence of pre-B cell receptor formation

The pre-B cell receptor (pre-BCR), consisting of the μ heavy chain (μHC) and the surrogate light chain (SLC, Vpre-B and λ5), plays important roles during B cell development. The formation of the pre-BCR, which enables the nascent immunoglobulin HC to associate with the SLC, is considered a prerequisite for B cell development. However, a significant number of peripheral mature (leaky) B cells exist in SLC-deficient mice. These leaky B cells develop in the absence of pre-BCR and do not undergo the pre-BCR checkpoint. The antibody repertoires of leaky B cells thus reflect the absence of pre-BCR function. To investigate how the absence of the pre-BCR is circumvented by these leaky-B cells and examine the effect of the pre-BCR checkpoint on the antibody system, we analyzed the antibody repertoires of λ5-deficient (λ5−/−) mice using next-generation sequencing. In λ5−/− mice, spleen B cells displayed different patterns of VDJ-usage, relative to those in wild-type (WT) mice. Moreover, leaky B cells were neither derived from unusual B2 cells, characterized by particular LC gene rearrangements in the absence of pre-BCR signaling, nor from B1 cells, originating from different B cell progenitors. Analysis of the CDR-H3 amino acid sequences of μ-chain repertoires revealed that certain bone marrow B cells with particular CDR-H3 profiles undergo clonal expansion in λ5−/− mice. Part of these CDR-H3s contain arginine(s) in the middle of the CDR-H3 loop in λ5−/− mice, whereas few arginine(s) exist in this middle loop in WT CDR-H3s in the absence of clonal expansion. This CDR-H3 feature in λ5−/− mice presumably reflects the role of the pre-BCR in autoantibody regulation, since arginine(s) are often found in the antigen-binding site of autoantibodies. Here, we present a unique viewpoint on the role of pre-BCR, by assessing the whole antibody repertoire formed in SLC-deficient mice