A prototype of the MeV gamma-ray imaging camera based on the full reconstruction of the Compton process has been developed. This camera consists of a micro-TPC that is a gaseous Time Projection ...Chamber (TPC) and scintillation cameras. With the information of the recoil electrons and the scattered gamma-rays, this camera detects the energy and incident direction of each incident gamma-ray. We developed a prototype of the MeV gamma-ray camera with a micro-TPC and a NaI(Tl) scintillator, and succeeded in reconstructing the gamma-rays from 0.3 to 1.3
MeV. Measured angular resolutions of ARM (Angular Resolution Measure) and SPD (Scatter Plane Deviation) for 356
keV gamma-rays were
18
∘
and
35
∘
, respectively.
In this paper, we show the influence of intrachannel crosstalk in an optical switch network. The intrachannel crosstalk is mainly due to a signal that is not sufficiently blocked by the optical ...switch. The signal has a broadband spectrum and causes coherent crosstalk at the optical switching node. We investigate analytically the relationship between the channel isolation of the optical switching node that the optical switch network comprises and the crosstalk penalty due to the broadband signal. We confirm experimentally that the relationship is suited to the optical switch network that emulates an optical cross-connect system. We also show experimentally that it is important to use the optical switch with a high channel isolation level in the entire range of the signal bandwidth in order to suppress the impairment due to the crosstalk. We confirm that in a 50-GHz spaced system, a 44-Gb/s return-to-zero differential quadrature phase-shift-keying signal is sufficiently transmitted without a crosstalk penalty through 24 optical switching nodes, comprising wavelength selective filters with a high channel isolation level in the entire range of the signal bandwidth.
A/Hong Kong/483/97 (H5N1) influenza virus (HK483) isolated from the third patient during the outbreak of chicken and human influenza in Hong Kong in 1997 was shown to be neurovirulent in mice. HK483 ...was inoculated intranasally to mice, and the invasion routes of the virus in the central nervous system (CNS) were investigated by immunohistochemical and in situ hybridization. The pathological changes consisted of bronchopneumonia, ganglionitis, and nonpurulent encephalomyelitis of the brain stem and the anterior part of the thoracic cord. Viral antigens and viral nucleic acids (RNA and mRNA) were demonstrated in the pterygopalatine, trigeminal and superior ganglions prior to or simultaneously with their detection in the CNS. The antigens and nucleic acids were also observed in the olfactory bulb from an early stage of the infection. In the spinal cord, virus-infected cells were first demonstrated in the grey matter of the thoracic cord. The virus, which primarily replicated in the lungs, was considered to invade the thoracic cord via cardiopulmonary splanchnic nerves and sympathetic nerves. These findings indicate that the virus reached the CNS through afferent fibers of the olfactory, vagal, trigeminal, and sympathetic nerves following replication in the respiratory mucosa.
Abstract Anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA) is a rare anomaly. It may contribute to myocardial ischemia or sudden death, although the lesion is usually ...asymptomatic. We report a sudden death case of a 58-year-old man with ARCAPA coexisting with severe atherosclerotic coronary artery disease. He had been healthy until he complained of chest pain, several days before death, despite the discovery of heart murmur in childhood and suspicion of valvular heart disease. The autopsy revealed not only typical findings of the right coronary anomaly with well-developed collateral circulations but also severe atherosclerotic lesions of the left coronary artery, and ischemic change of the myocardium in the left and right coronary arterial perfusion territory. In addition to the “coronary steal” phenomenon primarily caused by ARCAPA, the reduced flow of both coronary arteries and further increase of “coronary steal” due to atherosclerotic obstructive coronary disease might have contributed to the patient’s death.
To inspect volume expansion effect on the morphological features of martensite under continuous cooling conditions in which the transformation area (i.e. austenite) steadily decreases, we observed ...the martensitic transformation behaviour of 0.9C steel in-situ on free surfaces. The microstructural evolution of surface martensite with an abnormal grain size and that of coarse and fine lath martensites was observed, in the stated order, under continuous cooling conditions; each martensite exhibited a different morphology. The differences in martensite morphology are discussed from elastic strain viewpoint induced by incipient-formed martensite..
The realization of high-intensity, pulsed spallation neutron sources such as J-PARC in Japan and SNS in the US has brought time-of-flight (TOF) based neutron techniques to the fore and spurred the ...development of new detector technologies. When combined with high-resolution imaging, TOF-based methods become powerful tools for direct imaging of material properties, including crystal structure/internal strain, isotopic/temperature distributions, and internal and external magnetic fields. To carry out such measurements in the high-intensities and high gamma backgrounds found at spallation sources, we have developed a new time-resolved neutron imaging detector employing a micro-pattern gaseous detector known as the micro-pixel chamber (μPIC) coupled with a field-programmable-gate-array-based data acquisition system. The detector combines 100μm-level (σ) spatial and sub-μs time resolutions with low gamma sensitivity of less than 10−12 and a rate capability on the order of Mcps (mega-counts-per-second). Here, we demonstrate the application of our detector to TOF-based techniques with examples of Bragg-edge transmission and neutron resonance transmission imaging (with computed tomography) carried out at J-PARC. We also consider the direct imaging of magnetic fields with our detector using polarized neutrons.
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