Kazumi Makishima

The X-ray spectra of high-luminosity active galactic nuclei observed by Ginga

Results are presented on the X-ray emission from 13 objects, observed by Ginga as part of a spectral survey of bright quasars in the energy range 2-20 keV. The distribution of the power-law energy index for this sample has a mean of 0.81 and shows significant intrinsic dispersion, σ = 0.31, values which are broadly compatible with those from samples of lower luminosity active galactic nuclei. The mean spectral slope is clearly too sleep to fit the spectrum of the cosmic diffuse X-ray background (CXB) at energies less than 20 keV, confirming the spectral paradox in the discrete-source explanation of the CXB

Effects of histamine and interleukin-4 synthesized in arterial intima on phagocytosis by monocytes/macrophages in relation to atherosclerosis

We investigated the localization of histidine decarboxylase (HDC), which is the rate‐limiting enzyme that generates histamine from histidine, in human aorta/coronary artery. RT‐PCR and immunohistochemical staining revealed that the HDC gene was expressed in monocytes/macrophages and T cells in the arterial intima but not in smooth muscle cells in either the arterial intima or the media. A luciferase promoter assay with U937 and Jurkat cells demonstrated that interleukin‐4 (IL‐4) inhibited the expression of the HDC gene. In contrast, among a scavenger receptor family, IL‐4 as well as histamine up‐regulated U937 cells to express the LOX‐1 gene but not the SR‐A gene, which genes encode receptors that scavenge oxidized lipids. These findings suggest that histamine synthesized in the arterial wall participates in the initiation and progression of atherosclerosis and that IL‐4 can act as an important inhibitory and/or stimulatory factor in the function of monocytes/macrophages modulated by histamine in relation to the process of atherosclerosis.

Spectra and pulse period of the binary X-ray pulsar 4U 1538-52

The 530 s binary X-ray pulsar 4U 1538-52 was observed from the X-ray astronomy satellite Tenma in 1983 June-July. An improved orbital ephemeris was derived. Also, high-quality X-ray spectra were obtained by taking into account the contribution of the Galactic ridge emission. It was found that the iron K-line emission from this source is weak, contrary to previous reports. The observed pulsation period, about 529.8 s, is about 0.4 s longer than that measured in 1976-1977, implying an average spin-down rate of 3.8 x 10 to the -9th s/s. In addition, there is some evidence for a much larger rate of instantaneous period increase. These results suggest that 4U 1538-52 is a wind-fed pulsar, and its pulsation period changes in a random-walk manner in response to fluctuations in the external torque. This is very similar to the case of Vela X-1. 46 references.

Simultaneous Multifrequency Observations of the BL Lacertae Object Markarian 421

Simultaneous multifrequency observations of the BL Lac object Mrk 421 covering radio through X-ray wavelengths were performed on two occasions separated by 5 weeks in January and March 1984, and each observation was coordinated for about 1 week. Composite multifrequency spectra of the central nonthermal component were obtained at the two epochs after subtracting the optical and infrared light of the underlying galaxy. The spectra show the gradual steepening toward high frequency; the power law indices are about 0.1, about 0.6, and about 1.0 for radio, infrared-optical, and UV bands, respectively. The UV and optical-infrared fluxes decreased by about 20 percent in 5 weeks, while the radio flux remained stable. The X-ray flux decreased by a factor of about 2, and the change was more pronounced at hard X-rays, which suggest that X-ray emission possibly consists of two components. The degree of polarization at the optical band varied on the time scale of a few days, while the position angle remained unchanged. Physical parameters of Mrk 421 are discussed in terms of the synchrotron self-Compton model. 55 references.

Effect of background noise on perception of English speech for Japanese listeners

OBJECTIVES To avoid the accidents induced by confusions of non-native speech perception in the presence of noise at work, this study examined the effect of background noise on the discrimination of English speech for Japanese listeners. METHODS Normal hearing Japanese subjects, who have English learning experience to the level of college graduates, were tested with the CID W-22 word list in quiet settings and in the presence of white, low-frequency weighted (pink noise), or aircraft noise. RESULTS The discrimination scores were reduced as S/N ratio decreased, and more adversely affected by background white noise than pink or aircraft noise. The individual variability of English word discrimination scores for Japanese listeners was much larger as the S/N ratio decreased. The typical confusions among phoneme were /m/, /n/, and /s/. CONCLUSIONS The results of this study suggested that ineffective use of speech cues and difference in composition of English phonemes from Japanese could be responsible for degraded speech discrimination of non-native speech in noise. Moreover, it was expected that Japanese workers with age related hearing loss at higher frequencies might have great difficulty in perceiving English speech sounds in the presence of noise.

Differentiation of the rat stria vascularis

The differentiation of the rat stria vascularis (SV) was investigated by light- and electron microscopy and by immunocytochemistry. Loss of the basal lamina at the epithelial-mesenchymal interface of SVs as indicated by immunoreactions of laminin and fibronectin induces the formation of vascular feet by basal infoldings of the marginal cells (MCs), and the development of the strial capillaries (SCs) by mesenchymal cells in a manner of vasculogenesis is progressing at the same time. The production of fibronectin in the rough endoplasmic reticulum of mesenchymal cells and the involvement of this glycoprotein in a mechanical linkage between the vasoformative mesenchymal cells and endothelial ones of the SCs are indicated by immunocytochemistry. The plasma membrane of the marginal cells (MCs) begins to show immunoreactions of Na+.K+ ATPase at postnatal day 5 and is conjugated to each other by tight junctions at postnatal day 14. The apical tubules of the differentiating MCs do not seem to be involved in the endocytotic activity but are involved in the plasma membrane supply for the rapid differentiation.

Histopathologic correlates of otoneurologic manifestations following head trauma

The clinical course of patients dying of head trauma and the physiologic evaluation of audition in guinea pigs subjected to several forms of head trauma are correlated with the histopathologic findings in the brains and temporal bones. In the patients there was wide spread hemorrhage, edema, disorganization and disruption of neural tissue. Loss of Purkinje cells and other neural elements was prominent. The temporal bone findings in the patients included laceration of and hemorrhage into the VHIth nerve as well as bleeding into the scala tympani. The membranous labyrinths demonstrated no specific changes secondary to the trauma. The guinea pigs developed a central form of hearing loss with elevated thresholds for evoked responses from the inferior colliculus and normal AC cochlear potentials. In the animals hemorrhage in the substance of the brain, necrosis of neural tissue, edema, disorganization and disruption were prominent. Although there was extravasation of blood in the tympanic and vestibular scalae, the membranous structures of the inner ears were well preserved.

Immunopathological Study of the Larynx: IgA Distribution and Secretory Activity

Using immunofluorescent and histopathological techniques, we studied the distribution and secretory activity of the glands of the larynx from 55 humans. The cavity of the larynx was covered with secretory glandular cells with the exception of the true vocal cords, aryepiglottic folds and upper part of the laryngeal surface of the epiglottis. Immunofluorescent study revealed the presence of IgG and other immunoglobulins throughout the connective tissue ground in each laryngeal mucosa. The most striking was seen in the staining pattern of IgA. Diffuse fluorescence for IgA was observed not only in the submucosal or periglandular connective tissue area but also in the intraepithelial or submucosal glands. Secretory component synthesis was found mainly in each serous-type glandular epithelium or acinus. In the submucosal or periglandular area, IgA producing plasma cells were numerous. Our observations suggest that IgA, produced locally, is secreted via the glandular cells as secretory component — SIgA. Secretory activity of SIgA in these glandular tissues indicates that the larynx is possibly an immunologically active organ in the upper respiratory tract.

Delays of Optical Bursts in Simultaneous Optical and X-Ray Observations of MXB 1636-53

Observations of simultaneous optical and X-ray bursts from 4U/MXB 1636-53 were made using the Hakucho burst monitor system and optical telescopes at the European Southern Observatory during 1979 and 1980. The six best cases among the 10 coinciding observations are analyzed in terms of a model in which the optical emission is the result of reprocessing of X-rays (through blackbody heating). From this analysis, the temperature (spatially averaged) and size of a reprocessor, and the smearing and delay of the optical bursts are obtained. For the maximum temperatures of the optical reprocessor, the values differ from burst to burst, ranging from about 3 x 10 to the 4th to about 10 to the 5th K. The present analysis suggests that the size of the reprocessor varies by a factor of a few. For the smearing of the optical bursts an upper limit of a few seconds is derived. The most important result of this analysis is that the delay times are not the same for all bursts. The possible constraints which these results put on a low-mass binary model of this burst source are discussed.

Local immune system in the developing fetal larynx

Using histopathological and immunofluorescent techniques, we investigated the development of the glandular system of the larynx from 12 human fetuses. Glandular buds were first observed at the fourth month of gestation and glandular distribution became evident from the fifth month in the larynx. Ciliated or nonciliated epithelium covered the cavity of the larynx, with the exception of the true vocal cord. Immunofluorescent examination revealed the presence of IgG in the fetal larynx, but there was little fluorescence for IgA, IgM and IgE. Secretory component (SC) synthesis, on the other hand, was found in each serous‐type glandular epithelium or acinus from the fourth month on. Our observations suggest that the local immune system by SC, which binds to IgA as SIgA in human laryngeal mucosa, is inherently acquired in the fetal larynx.