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A girl attended our clinic with inflammation of the marginal gingiva. The surfaces of central incisors had severe enamel defects caused by trauma to the primary incisors. Swollen but non-ulcerated gingiva was present on the surface of the left central incisor. The gingival mass was surgically removed. Immunohistochemical analyses revealed that the resected mass included epithelial tissue expressing odontogenic ameloblast-associated protein (ODAM), which is a marker of junctional epithelium. It was likely ectopic junctional epithelium that had formed due to disorganization of the enamel organ during development caused by dental trauma to the primary incisors.

Fatigue pre-cracking performance and fracture toughness in polycrystalline tungsten (W) and molybdenum (Mo) have been investigated in relation to grain boundary (GB) configuration with respect to the crack advance direction. Sub-sized, single edge notched bend (SENB) specimens with three different orientations, R-L (ASTM notation) for a forged Mo rod and L-S and T-S for a rolled W plate, were pre-cracked in two steps: fully uniaxial compression fatigue loading to provoke crack initiation and its stable growth from the notch root, and subsequent 3-point bend (3PB) fatigue loading to extend the crack. The latter step intends to minimize the influence of the residual tensile stresses generated during compression fatigue by moving the crack tip away from the plastic zone. It is shown that fatigue pre-cracking performance, especially pre-crack extension behavior, is significantly affected by the specimen orientation. The R-L orientation, giving the easiest cracking path, permitted crack extension completely beyond the plastic zone, while the L-S and T-S orientations with the thickness cracking direction of the rolled plate sustained the crack lengths around or possibly within the plastic zone size due to difficulty in crack advance through an aligned grain structure. Room temperature fracture toughness tests revealed that the 3PB fatigued specimens exhibited appreciably higher fracture toughness by about 30% for R-L, 40% for L-S and 60% for T-S than the specimens of each orientation pre-cracked by compression fatigue only. This indicates that 3PB fatigue provides the crack tip front out of the residual tensile stress zone by crack extension or leads to reduction in the residual stresses at the crack tip front. Strong dependence of fracture toughness on GB configuration was evident. The obtained fracture toughness values are compared with those in the literature and its strong GB configuration dependence is discussed in connection with the appearance of pop-in.

Fracture toughness of the divertor armor in ITER needs to be elucidated for prediction of the response of armor materials to intense heat loading. The present study has been performed to establish a method for inserting a well, defined fatigue precrack into the test specimens and measure the reliable fracture toughness values of tungsten (W) materials that exhibit low temperature brittleness. Sub-sized, single edge notched bend (SENB) specimens with two orientations, L -T and T-L, taken from a commercially available pure W plate manufactured in accordance with the ITER material specifications (ITER specification W, ALMT-grade), were precracked in two-step fatigue loading: fully uniaxial compression fatigue to provoke a crack from the notch tip, and subsequent 3-point bend (3 PB) fatigue to extend the crack length for the minimization of influence of the residual tensile stresses generated by compression fatigue. During compression and 3 PB fatigue loading the fatigue crack was closely monitored by continuous in-situ observations on the notch tip. Continuous tracing of the crack tip position has enabled capture of the fatigue cracking behavior as a kinematic response in a rolled W material, disclosing a marked difference in crack inducement and extension between the two orientations. 3 PB fracture testing of the precracked specimens at room temperature (RT) yielded ~10 MPa√m for the T-L and 12~13 MPa√m for the L -T orientation as fracture toughness: anisotropic variation in fracture toughness of the W plate is comparatively small. Fracture surface observations reveal that a crack path is entirely transgranular for the L -T, while crack propagation involves intergranular fracture to a large extent for the T-L orientation. These results obtained are discussed and compared with the literature data.

To compare sub-solid nodules detectability (SSND) between ultra-low-dose chest digital tomosynthesis (ULD-CDT) with/without iterative reconstruction (IR) and chest radiography (CR) by using low-dose computed tomography (LDCT) as the standard of reference (SOR).Institutional Review Board approved this study and written informed consent was obtained. In a single visit, 79 subjects underwent ULD-CDT at 120 kV and 10 mA, CR and LDCT (effective dose: 0.171, 0.117 and 3.52 mSv, respectively). Sixty-three coronal images were reconstructed using CDT with/without IR. SOR as to SSN presence was determined based on LDCT images. Seven radiologists recorded SSN presence and locations by continuously-distributed rating. Receiver-operating characteristic (ROC) analysis was used to compare SSND of ULD-CDT with/without IR and CR, in total and subgroups classified by nodular longest diameter (LD) (or9 mm) and mean CT attenuation value (CTAV) (or-600 Hounsfield of Unit (HU)). Detection sensitivity (DS) was compared among 4 groups classified by combination of the identical thresholds: nodular LD (9 mm) and mean CTAV (-600 HU) in each of ULD-CDT with/without IR and CR with Friedman and Wilcoxon signed rank test.SSND for total 105 SSNs as well as larger SSNs with nodular LD of 9 mm or more at ULD-CDT with IR was higher than either that at ULD-CDT without IR or CR, as the areas under the ROC curve were 0.66 ± 0.02, 0.59 ± 0.01 and 0.52 ± 0.01, respectively (p 0.05). DS at ULD-CDT with IR was 69.5 ± 10.8% in groups with larger (LD 9 mm) and more-attenuated (-600 HU) SSNs, and higher than in the other 3 groups (p 0.05).ULD-CDT with IR demonstrated better SSND than that without IR or CR, with increased DS for larger and more-attenuated SSNs compared with the remaining ones.

We investigated whether the use of a newly developed columnar-crystal-type photostimulable-phosphor plate (CP1M200, referred to as system C) helps to provide improved edge-enhanced effect in phase contrast imaging. Physical characteristics of 2 conventional particulate-crystal-type photostimulable-phosphor plates (RP-5PM, referred to as system A and RP-6M, referred to as system B) and system C were measured. Then, an acrylic plate phantom and RMI152 phantom were imaged using 3 types of plates, and the edge-enhancement effects were evaluated based on the profile curve of the acrylic plate phantom. Visual evaluation of the RMI152 phantom images was conducted. The results showed that the modulation transfer function (MTF) of system C was superior to those of the other systems. The WS of system C was superior to those of the other systems in the low frequency band region, and inferior to those of the other systems in the high frequency band region. The presence of an edge-enhanced image was not detectable in the profile curve of the acrylic plate in system A, although that was shown in systems B and C due to their excellent sharpness. In the visual image evaluation of the RMI152 phantom, image quality of system C was superior to those of the other systems. Phase contrast imaging with a digital detector of a columnar-crystal-type photostimulable-phosphor plate is considered to provide improved edge-enhancement over that of conventional plates.

It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase contrast imaging with x-ray from synchrotron radiation or micro-focus x-ray tubes. In this study, we conducted the phase contrast imaging of a plastic fiber and plant seeds using a customized mammography equipment with a 0.1 mm focal spot, and the improvement of image sharpness was evaluated in terms of spatial frequency response of the images. We observed that the image contrast of the plastic fiber was increased by edge enhancement, and, as predicted elsewhere, spectral analysis revealed that as the spatial frequencies of the x-ray images increased, so did the sharpness gained through phase contrast imaging. Thus, phase contrast imaging using a practical molybdenum anode tube with a 0.1 mm-focal spot would benefit mammography, in which the morphological detectability of small species such as micro-calcifications is of great concern. And detectability of tumor-surrounded glandular tissues in dense breast would be also improved by the phase contrast imaging.

Phase contrast images were obtained experimentally by using a customized mammography unit with a nominal focal spot size of 100 microm and variable source-to-image distances of up to 1.5 m. The purpose of this study was to examine the applicability and potential usefulness of phase contrast imaging for mammography. A mammography phantom (ACR156 RMI phantom) was imaged, and its visibility was examined. The optical density of the phantom images was adjusted to approximately 1.3 for both the contact and phase contrast images. Forty-one observers (18 medical doctors and 23 radiological technologists) participated in visual evaluation of the images. Results showed that, in comparison with the images of contact mammography, the phantom images of phase contrast imaging demonstrated statistically significantly superior visibility for fibers, clustered micro-calcifications, and masses. Therefore, phase contrast imaging obtained by using the customized mammography unit would be useful for improving diagnostic accuracy in mammography.

胃,十二指腸潰瘍穿孔に対する保存的治療法の適応を明確にすることを目的として,保存的治療の成功した32例をA群(胃6例,十二指腸26例),保存的治療から手術に移行した5例(胃2例,十二指腸3例)をB群としてretrospectiveに検討した. A群の特徴はB群に比し1) 若年である, 2) 初診時のCT, USにおいて左,右横隔膜下,脾腎境界,モリソン窩,肝下面,左,右傍結腸溝,ダグラス窩のうち腹水貯留部位は2カ所以内である, 3) 腹部筋性防御が初診後24時間以内に軽快する, 4) 腹水量は経時的に減少する,という点にあり,これらを満たすことが保存的治療の適応条件と考えられた.手術移行への遅延は合併症や入院期間を遷延させるため,保存的治療を行う場合には臨床所見の変化を緻密に観察し,手術に移行するタイミングを逃さないことが重要と思われた.

The noise power spectra of radiographic film have been used to analyze the graininess of radiography. Furthermore, it has recently become clear that graininess analysis, especially at low space frequencies, is needed for quantitative evaluation of a radiographic screen/film system. This paper describes a method for analysis of film at low space frequencies that is based on the maximum entropy method (MEM). This method can determine the basic order of MEM to maximize the ratio of the order to the power spectrum at low space frequencies. Experimental results confirmed that the noise power to express the radiographic influence on films can be precisely measured at ultralow space frequencies.

To compare detectability of simulated ground-glass nodules (GGNs) on chest digital tomosynthesis (CDT) among 12 images obtained at 6 radiation doses using 2 reconstruction algorithms and to analyze its association with nodular size and density.74 simulated GGNs [5, 8 and 10 mm in diameter/-630 and -800 Hounsfield units (HU) in density] were placed in a chest phantom in 14 nodular distribution patterns. 12 sets of coronal images were obtained using CDT at 6 radiation doses: 120 kV-10 mA/20 mA/80 mA/160 mA, 100 kV-80 mA and 80 kV-320 mA with and without iterative reconstruction (IR). 10 radiologists recorded GGN presence and locations by continuously distributed rating. GGN detectability was compared by receiver operating characteristic analysis among 12 images and detection sensitivities (DS) were compared among 12 images in subgroups classified by nodular diameters and densities.GGN detectability at 120 kV-160 mA with IR was similar to that at 120 kV-80 mA with IR (0.614 mSv), as area under receiver operating characteristic curve was 0.798 ± 0.024 and 0.788 ± 0.025, respectively, and higher than six images acquired at 120 kV (p 0.05). For nodules of -630 HU/8 mm, DS at 120 kV-10 mA without IR was 73.5 ± 6.0% and was similar to that by the other 11 data acquisition methods (p = 0.157). For nodules of -800 HU/10 mm, DS both at 120 kV-80 mA and 120 kV-160 mA without IR was improved by IR (56.3 ± 11.9%) (p 0.05).CDT demonstrated sufficient detectability for larger more-attenuated GGNs (8 mm) even in the lowest radiation dose (0.17 mSv) and improved detectability for less-attenuated GGNs with the diameter of 10 mm at submillisievert with IR. Advances in knowledge: IR improved detectability for larger less-attenuated simulated GGNs on CDT.

An AISI 1020-grade mild steel, with a small amount of aluminum, was spray-formed by nitrogen gas-atomization and deposition. The spray-formed 1020 steel contained 0.05 mass% of nitrogen and 0.06 mass% of aluminum. Rolling the spray deposit at 1123 K for a thickness reduction of 70% and subsequent normalizing at low austenitic temperatures produced a fully dense steel having a refined ferrite grain size as small as 3 μm. This grain refinement resulted from the pinning of prior austenite grain boundaries by fine AlN particles which precipitated during the thermomechanical treatments. Room-temperature tensile properties (YS: 550 MPa, UTS: 630 MPa, elongation: 23%), exceeding those of conventional microalloyed high-strength low alloy steels, were achieved in the normalized state. The AlN-pinned fine-grained microstructure survived subsequent re-austenizing at temperatures as high as 1273 K. When tensile-tested in the austenite region at 1123 K, the microalloyed 1020 steel showed a large elongation exceeding 200%.

This paper presents a novel system to track a moving human in living environment. The tracking technique is based on dead reckoning navigation in which the location of the traveler is estimated from measurements of moving distance and direction. The proposed system consists of a portable instrument of the pedestrian and a monitoring instrument in a base station. In the pedestrian portable instrument, the present position is detected at every step from the number of walking steps from the pedometer and the direction from the terrestrial magnetic sensor. In the base station, the map matching process is applied to the positional data transmitted by the portable telephone, and the walking trajectory is depicted on the display of a PC. From the experiments for tracking the walking of a healthy person in an urban area, a residential area, and a mountain path, it is confirmed that the proposed system can track the movement. Also, by transmitting the environmental sound around the pedestrian such as announcement of bus stops through a portable telephone, the possibility is shown for pedestrian tracking including movement by public transport. © 2000 Scripta Technica, Electron Comm Jpn Pt 3, 83(7): 12–21, 2000

Magnetic properties of GdCoC 2 and GdNiC 2 are investigated by means of magnetization measurement of single crystals and 155 Gd Mossbauer spectroscopy of powdered samples. GdCoC 2 is an antiferromagnet below T N = 15.6 K and shows an order-order transition at T t = 14.0 K. The measurements of 155 Gd Mossbauer effect and magnetization process reveal that the Gd moments align noncollinearly by an angle of 48° from the a -axis in the c -plane. GdNiC 2 is an antiferromagnet below T N = 20.0 K. The Gd moments align noncollinearly by angles of 18° from the c -axis and 45° from the a -axis in the c -plane. By the 155 Gd Mossbauer measurements, crystal field parameters are derived to be A 2 0 = -498 K/ a 0 2 in GdCoC 2 and A 0 2 = 277 K/ a 0 2 in GdNiC 2 .

Magnetic properties of powdered and single-crystalline DyNiC2 are investigated by means of magnetization measurement, neutron diffraction and 161Dy Mossbauer spectroscopy. DyNiC2 is a noncollinear antiferromagnet below TN = 7.6 K. Below Tt1 = 3.3 K there exists a commensurate antiferromagnetic phase described by a propagation vector of [ 1 2 1 2 0 ]. The Dy moments of 9.0μB align with a direction defined by angles of θ = 49° from the c-axis and φ = 34° from the a-axis in the c-plane at 1.5 K. The commensurate and incommensurate phases coexist between Tt1 and Tt2 = 5.0 K. The incommensurate phase with a sinusoidal moment modulation is described by a propagation vector of [ 1 2 1 2 − δ 0 ] (δ = 0.11) where the moments modulated with an amplitude of 9.2μB align with a direction of θ = 45° and φ = 77° at 4.2 K. The assumption that the moment component along the a-axis decreases with increasing temperature between Tt1 and Tt2 gives satisfactory explanation about anomalous behaviors in temperature dependences of magnetic susceptibility and neutron reflection intensities.

The magnetic properties of DyCoC2 have been investigated by means of magnetization measurements, powder neutron diffraction and 161Dy Mossbauer spectroscopy. The magnetization versus temperature curves of a single-crystalline sample reveal that the magnetic structure of DyCoC2 is a simple collinear ferromagnetic one below TC = 10.0 K. At 4.2 K, the magnitude of the Dy moment is 8.7(1)μB, whose direction is defined by an angle of 38.0(5)° from the a-axis toward the c-axis. The magnetic structure and the magnitude of the moment are also confirmed by the results of powder neutron diffraction experiments and 161Dy Mossbauer spectroscopy, respectively.

We investigated the neonatal entrance-surface dose (ESD) and doses of scattered radiation emitted by a digital mobile X-ray system. The system is equipped with a novel flat-panel detector and is used in the neonatal intensive care unit. In the present study, the following three experiments were performed on frequently used X-ray-imaging condition: (1) the digital characteristics of the FPD were evaluated; (2) the ESD to a water-equivalent phantom was measured with a patient skin dosimeter (PSD); and (3) the scattered radiation around the incubator was measured with an ionization chamber survey meter. The digital characteristic curve showed that the system had excellent linearity and that the contrast characteristics were not affected by the tube voltage in the range of 50–110 kV. The ESD was 51–52 μGy with an 8-cm-thick phantom and 33–34 μGy with a 4.5-cm phantom, for one exposure. The doses measured around the incubator were 0.1–0.6 μSv or below measurable limits. Use of the new device demonstrates the potential of reducing the ESD to the patient and operator.

With use of the phase shift of X-rays that occurs when they pass through an object, phase-contrast imaging (herein referred to as “phase imaging”) can produce images different from those of conventional contact imaging (herein referred to as “conventional imaging”). For this reason, assessment of the image quality based on noise-equivalent quanta (NEQ) and detective quantum efficiency (DQE) which does not include object-based information may not be appropriate for comparison of image quality between phase and conventional images. As an alternative method, we conceived a new image-quality assessment method with images that contain information about an object. First, we constructed images with an object and without an object under the same imaging parameters; then, we obtained two-dimensional power spectra by Fourier transform of those images. Second, we calculated the radial direction distribution function with the power spectra, and the distribution of signal intensity, which we defined as a signal intensity distribution function (SIDF). In this way, differences in image quality were evaluated relatively based on the SIDF of the imaged object. In our study, we first confirmed that phase-imaging evaluation was not appropriate by comparing NEQ and DQE of conventional, magnification, and phase imaging. Further, comparing the image quality of projected plant seeds by employing conventional, magnification, and phase imaging, we found that the phase-imaging method provided a higher image quality regarding edge sharpness than did conventional and magnification imaging. Therefore, based on these results, our image assessment method is considered useful for evaluation of images which include object-based information.

The medium-range structure of a heat-treated Al 85 Y 10 Ni 5 amorphous alloy was investigated by small-angle X-ray scattering, calorimetric analysis, wide-angle X-ray diffraction and transmission electron microscope measurements. It is observed that crystalline particles having a definite boundary are precipitated by annealing at supercooled liquid temperatures and that most of the precipitates consist of the Al fcc crystalline phase. The integrated intensities of the small-angle scattering and the Guinier radii of the precipitates increase on annealing for time duration ∼ 5.4 ks, the integrated intensities and the Guinier radii are invariant, i.e., growth of the precipitates ceases. After annealing for 518.4 ks, the diameters of the precipitates exhibit a narrow distribution centered around 200 A.

声門閉鎖不全と呼吸嚥下協調不全が原因で唾液を誤嚥し、無気肺を形成したと思われる頸髄損傷者に対し、従来のCPTに加え、発声練習と呼吸嚥下協調訓練を実施したところ、効果的であった。急性期頸髄損傷者では、反回神経損傷、挿管による声帯圧迫、頸部の肢位と周囲筋の過剰な筋活動、麻酔の方法等が無気肺や誤嚥の原因となる可能性があリ注意が必要である。特に、嗄声がみられる場合は、声帯機能の観察が不可欠と思われる。

It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase contrast imaging with x-ray from synchrotron radiation or micro-focus x-ray tubes. In this study, we conducted the phase contrast imaging of a plastic fiber and plant seeds using a customized mammography equipment with a 0.1 mm focal spot, and the improvement of image sharpness was evaluated in terms of spatial frequency response of the images. We observed that the image contrast of the plastic fiber was increased by edge enhancement, and, as predicted elsewhere, spectral analysis revealed that as the spatial frequencies of the x-ray images increased, so did the sharpness gained through phase contrast imaging. Thus, phase contrast imaging using a practical molybdenum anode tube with a 0.1 mm-focal spot would benefit mammography, in which the morphological detectability of small species such as microcalcifications is of great concern. And detectability of tumor-surrounded glandular tissues in dense breast would be also improved by the phase contrast imaging.

RATIONALE AND OBJECTIVES The image quality of a newly developed full-field digital phase contrast mammography (PCM) system and of a conventional screen-film (SF) mammography system were compared via images of a phantom and receiver operating characteristic (ROC) analysis of clinical images. METHODS Magnified (1.75X) PCM images were scanned (sampling rate, 43.75 microm) and then reduced to original-sized, 25-micron pixel images printed on photothermographic film. Along with corresponding SF images, the phantom images were evaluated subjectively, and the clinical images of 38 patients were subjected to ROC analysis of mass and microcalcification. RESULTS In the image quality of a phantom, the PCM exceeded the SF. In both mass and microcalcification, the ROC analysis Az values of the PCM clinical images surpassed those of the SF images. CONCLUSION The PCM provides better images than the SF. Clinical trials suggest superior detection of both mass and microcalcification by full-field digital PCM over conventional SF mammography.

We report a patient for whom systemic chemotherapy using gemcitabine was effective against local recurrence of pancreatic cancer. A 58-year-old man underwent pancreatoduodenectomy for a pancreatic head cancer. The diagnosis was Stage IVb poorly-differentiated tubular adenocarcinoma, scirrhous type, pT4, PL (+), P0, H0, pN2. However, after 21 months, gastrointestinal bleeding occurred. Gastroscopy and CT examination revealed a mass at the cut-end of the pancreas invading the stomach. The serum CA19-9 level was found to be elevated. Systemic chemotherapy was performed with a regimen of gemcitabine 1,000 mg/m2/week for 2 weeks, followed by a week rest. The recurrent tumor in the stomach disappeared, and the mass at the cut-end of the pancreas became small. The serum CA 19-9 level regained the normal value. Two years after the diagnosis of recurrence, he returned to work, and his chemotherapy is being continued as an outpatient.

The significance of hepatic arterial infusion chemotherapy (HAI) for the prognosis of metastatic colorectal cancer is controversial. We applied a clinical scoring system to find good candidates for HAI after hepatic resection. Ninety-four consecutive cases of hepatic metastases resected at a single institute were analyzed retrospectively. The cases were divided into 4 subgroups: those with a low risk score (0-2 points) with and without HAI and those with a high risk score (3-5 points) with and without HAI. The number of cases and the cumulative 5 year survival rate of each case were as follows: low risk score with HAI (n = 17) 64.1%, low risk score without HAI (n = 25) 27.4%, high risk score with HAI (n = 28) 16.9%, and high risk score without HAI (n = 24) 14.7%, respectively. These results suggest that hepatic resection with HAI seemed to contribute to the outcome for selected cases. The clinical scoring system may identify good candidates for HAI as well as predict recurrence after hepatic resection for metastatic colorectal cancer.

Sintering mechanism and physical properties of a Mo2FeB2, especially Cr containing (Mo2-xFe1-xCr2x)B2 ternary borides were studied for deepening the understanding of basic characteristics of newly developed Mo2FeB2 boride base cermets. Cr addition to the Mo2FeB2 significantly improved its sinterability due to the formation of a transient liquid phase. Cr containing Mo2FeB2 borides have excellent physical properties such as high hardness and young's modulus and are promising candidates for hard material applications.