Soft X-ray Photography Research Articles

Observations of Bark Tissues of 12 Angiospermous Trees by Soft X-ray Photography

Observations of Bark Tissues of 12 Angiospermous Trees by Soft X-ray Photography

Anticancer Effect of Biodegradable Magnesium on Hepatobiliary Carcinoma: An In Vitro and In Vivo Study.

Biliary-stent implantation has become an effective treatment for patients with malignant obstructive jaundice caused by hepatobiliary carcinoma. Stent restenosis due to tumor ingrowth is a common problem. In this study, we assessed a biodegradable form of magnesium (Mg) for its anticancer effect on hepatobiliary carcinoma, compared to the conventional stent material of titanium (Ti). The results showed that a Mg extract inhibited proliferation and induced apoptosis in human cholangiocarcinoma cells, while a Mg plate inhibited cell adhesion and destroyed the cytoskeleton in the process of biodegradation. In animal experiments with H22 tumor-bearing mice, Mg wires implanted in tumors exhibited an inhibitory effect on their growth compared with Ti wires. Fifteen days after implantation of metal wires, the mean tumor volume and weight in the Mg group were significantly smaller than in the Ti group. We observed the dynamic-degradation process of Mg wires in tumors and generation of H2 gas via soft X-ray photography and scanning electron microscopy. Histopathological analyses showed that apoptosis of tumor cells around Mg wires significantly increased, expression of carbonic anhydrase 9 significantly decreased, and the upstream protein hypoxia-inducible factor 1-alpha also decreased to some extent. Taken together, these results indicated that biodegradable Mg had antitumor properties both in vitro and in vivo, suggesting its potential application as a novel material for biodegradable biliary stents.

高温環境下におけるクロスプライCFRTP積層板のトランスバースクラック発生及び累積挙動の評価

The effects of environment temperature on initiation and multiplication of transverse crack in cross-ply carbon fiber reinforced thermoplastic (CFRTP) laminates have been investigated. Static tensile tests for the cross-ply laminates and the 90° unidirectional laminates were carried out at room temperature, 93 °C and 130 °C, respectively. The transverse cracks were observed by soft X-ray photography. The tensile strength and the failure strain in the cross-ply laminates and the 90° unidirectional laminates at high temperature decreased compared to the values at room temperature. It was also found that the behavior of initiation and multiplication of the transverse cracks in the cross-ply laminates was changed due to the environment temperature. The experimental results under different temperature were analyzed by Weibull distribution on the basis of probabilistic model. Next, the energy release rate was calculated due to formation of a new micro crack based on the Weibull distribution. The predicted transverse crack density by Weibull distribution was compared with the experiment result and the reasonability of using Weibull distribution to CFRTP cross-ply laminates under high temperature was verified. It was found that the critical energy release rate of CFRTP laminates has decreased at high temperature and the experimental results showed that the matrix strength was decreased at high temperature. Also, the fiber-matrix interfacial fracture on the fracture surface of the 90° unidirectional laminates was observed in some areas at high temperature whereas the matrix fracture was observed at room temperature. Therefore, it was suggested that the interface strength between polymer and fiber was decreased at high temperature.

高温環境下における熱可塑性CFRP積層板のトランスバースクラック発生・進展挙動調査

The effects of environment temperature on initiation and propagation of transverse crack in cross-ply carbon fiber reinforced thermoplastic (CFRTP) laminates have been investigated. Static tensile tests for the cross-ply laminates and the 90° unidirectional laminates were carried out at room temperature and high temperature (366K). The transverse cracks were observed by soft X-ray photography. In consequence, the tensile strength and the failure strain in the cross-ply laminates and the 90° unidirectional laminates at 366K decreased compared to the values at room temperature. It was also found that the behavior of initiation and propagation of the transverse cracks in the cross-ply laminates was changed due to the environment temperature. Fiber-matrix interfacial fracture on the fracture surface of the 90° unidirectional laminates was observed in some areas at high temperature whereas matrix fracture was observed at room temperature. Therefore, it was suggested that the interface strength between polymer and fiber was decreased at high temperature.

Prediction of initiation of transverse cracks in cross-ply CFRP laminates under fatigue loading by fatigue properties of unidirectional CFRP in 90° direction

A fatigue life to the initiation of transverse cracks in cross-ply carbon fiber-reinforced plastic (CFRP) laminates has been predicted using properties of the fatigue strength of unidirectional CFRP in the 90° direction. In the experiments, unidirectional [90]12 laminates were used to obtain a plot of maximum stress versus number of cycles to breaking, and two types of cross-ply laminates of [0/904]S and [0/906]S were used to evaluate the initiation and multiplication of transverse cracks under fatigue loading. Transverse cracks were studied by optical microscopy and soft X-ray photography. Analytical and experimental results showed good agreement, and the fatigue life for transverse crack initiation in cross-ply laminates was predicted successfully from the fatigue strength properties of the unidirectional CFRP in the 90° direction. The prediction results showed a conservative fatigue life than the experimental results.

Comparative Studies on Cotton Seed Germinability with Tetrazolium Viability Test and X-ray Contrast Methods

Seed viability testing provides valuable information for assessing seed lot germinability. However, most testing methods require destruction of seed prior to test. Because the dissected seeds for viability test cannot be used further evaluation, the nondestructively X-ray photography technique that can be applied for the evaluation of seed quality has been developed. In order to know the validity and accuracy of X-ray photography technique in seed evaluation test that conducted to remove the abnormal seed from a seed lot, we have compared the results from tetrazolium viability test, germination test and X-ray contrast method in cotton. Metallic salts treatment increased the efficiency of X-ray photographic method by enhancing the penetration of X-ray in abnormal or damaged seeds rather than normal seeds that have strong and well-organized tissues in seed. Cotton seeds presoaked for 16 hr in distilled water followed by soaking into metallic salt solution (5% NaI in water) for 60 min were easily classified seeds into dead seed and viable seed based on the radiography images obtained by X-ray radiation. We concluded that soft X-ray photography was reliable to find out the various defective characters due to heat and mechanical damage of seeds.

Evaluation of transverse crack initiation in interlaminar toughened CFRP cross-ply laminates under cyclic loading

Initiation and growth behaviors of a transverse crack occurred in interlaminar toughened CFRP cross-ply laminates under cyclic loading were evaluated. Specimens whose stacking sequence is [0/904]S and [0/906]S were formed with T800S/3900-2B prepreg. The specimen edges were observed with an optical microscope and a laser microscope to investigate the behavior of transverse crack initiation and growth. To observe the edge surface of the specimen at arbitrary loading cycles, a replica technique was used. In addition, soft X-ray photography was used to observe internal damage. The number of cycles to transverse crack initiation was predicted quantitatively by applying the normalized modified Paris law, which shows the relationship between transverse crack density growth rate and normalized energy release rate range associated with transverse crack formation. Analytical results showed good agreement with experimental results. It was found that transverse crack initiation in interlaminar toughened CFRP laminates can be evaluated by applying the normalized modified Paris law. Moreover, in comparison to the laminates with and without toughened layers, the fatigue life to transverse crack initiation was prolonged due to the toughened layers. From damage observation, it was cleared that a transverse crack path to the thickness direction of the laminate was prevented by polyamide particles in the toughened layers. Therefore, it was found that the toughened layers dispersed polyamide particles to prevent delamination are effective for obstructing initiation of a transverse crack under cyclic loading.

Are Dyslipidemia Following Obesity and Hyperglycemia as an Indicator of Diabetes Involved in Dental Caries Development in Zucker Rats?

Several studies indicated that both obesity and diabetes are related to dental caries development, but their involvement remains unclear. Thus, we investigated the effect of obesity and diabetes on dental caries development using obese Zucker fatty (ZF) rats, obese Zucker diabetic fatty (ZDF) rats, and Zucker lean (Lean) rats as controls. Eight ZF, 6 ZDF, and 7 Lean male rats were studied. We macroscopically examined the mandibular and maxillary molars and evaluated soft X-ray photographs for caries development. From each group, 5 mandibles and maxillae were examined histologically. The ZF rats’ average body weight was more than twice that of the other 2 groups, but the ZDF and Lean rats had comparable body weights. The average triglyceride and total cholesterol levels were elevated in the ZF and ZDF rats, but the ZF rats’ average triglyceride and total cholesterol levels were three times and twice, respectively, those of the ZDF rats. The ZDF rats became diabetic after 13 weeks of age and demonstrated a high blood glucose level (>500 mg/dL) after 23 weeks of age. The ZF rats had a significantly higher blood glucose level than that of Lean rats after 23 weeks of age but had about one-half that of the ZDF rats. The ZDF rats had significantly more molar caries and greater alveolar bone resorption than the other two groups; the ZF rats’ caries and bone resorption were moderately higher than those of the Lean rats. Histopathologically, crown caries progressed to apical periodontitis in 20% and 50% of the ZF and ZDF rats’ molars, respectively, corresponding to the alveolar bone resorption on the soft X-ray film. Dyslipidemia and hyperglycemia may involve dental caries development and obesity or diabetes could enable lesion progression to apical periodontitis in Zucker rats; diabetes enhances dental caries to a greater extent than obesity.

ステレオガイド下マンモトーム生検における標本撮影補助具の有効性の検討

ステレオガイド下マンモトーム生検における標本撮影補助具の有効性の検討

Alveolar bone regeneration using absorbable poly(L-lactide-co-ɛ-caprolactone)/β-tricalcium phosphate membrane and gelatin sponge incorporating basic fibroblast growth factor

The aim of this study was to evaluate the effects of combining a porous poly(L-lactide-co-ɛ-caprolactone)/β-tricalcium phosphate membrane and gelatin sponge incorporating basic fibroblastic growth factor (bFGF) on bone regeneration in mandibular ridges. Four full-thickness saddle-type defects (10 mm long × 5 mm deep) were symmetrically created in both edentulous mandibular alveolar ridges of 6 beagles. The dome-shaped membrane was secured to each defect site, and a gelatin sponge containing 200 μg bFGF was implanted on the left side of each defect (experimental group). Only the membranes (control group) were secured to the defect sites on the right. Three and 6 months later, 3 animals were killed. Bone regeneration was analyzed by soft X-ray photographs, micro-computed tomography (CT) images, and peripheral quantitative CT (pQCT), and then examined histologically. Soft X-ray examination revealed an increase in new bone volume in the experimental group 6 months postoperatively. pQCT showed that immature bone density was higher in the experimental group. Micro-CT images revealed well formed new bone along the original contour of the dome-shaped membrane in the experimental group. Histologically, inflammatory infiltration of tissue surrounding the membranes was slight. These results suggest that combining the poly( L-lactide-co-ɛ-caprolactone)/β-tricalcium phosphate membrane and bFGF-gelatin sponge is promising for alveolar ridge reconstruction.

Skeletal development and deformities in cultured larval and juvenile seven-band grouper, Epinephelus septemfasciatus (Thunberg)

The seven-band grouper, Epinephelus septemfasciatus (Thunberg), is currently recognized as a potential new species for aquaculture in Japan. This study describes normal and abnormal skeletal development of the jaw and vertebrae in cultured larvae and early juveniles of E. septemfasciatus. The ontogenetic stages at which skeletal deformities of jaw and vertebra developed were also described for this species. Osteological observations were made using a clearing and staining method for larvae and soft X-ray photographs for juveniles. A high incidence of skeletal deformities was observed in the jaws and vertebral column during the larval and juvenile stages. Most of the jaw deformities were explained by an abnormal maxilla curvature. Jaw deformities were visually evident from flexion stage after ossification of the deformed elements. Deformities in the vertebral column (mostly lordosis) were observed from the post-larval stage and became more evident as growth proceeded. The lordosis generally occurred on the positions of the 8–11th vertebra. These types of deformities are compared with those of other species, and possible causative factors of the skeletal deformities are discussed.

High-cycle fatigue characteristics of quasi-isotropic CFRP laminates

High-cycle fatigue characteristics of quasi-isotropic carbon fiber reinforced plastic (CFRP) laminates [−45/0/45/90]s up to 108 cycles were investigated. To assess the fatigue behavior in the high-cycle region, fatigue tests were conducted at a frequency of 100 Hz, since it is difficult to investigate the fatigue characteristics in high-cycle at 5 Hz. Then, the damage behavior of the specimen was observed with a microscope, soft X-ray photography and a 3D ultrasonic inspection system. In this study, to evaluate quantitative characteristics of both transverse crack propagation and delamination growth in the high-cycle region, the energy release rate associated with damage growth in the width direction was calculated. Transverse crack propagation and delamination growth in the width direction were evaluated based on a modified Paris law approach. The results revealed that transverse crack propagation delayed under the test conditions of less than σ max/σ b = 0.3 of the applied stress level.

407 Cross-Ply CFRP積層板の高サイクル疲労におけるトランスバースクラック及び層間はく離進展挙動の調査(高分子/高分子基複合材料1)

Damage growth behavior of transverse crack and delamination in cyclic loading was studied with cross-ply laminates of carbon fiber reinforced plastics (CFRPs) composite. Damage of the specimens during the fatigue test was observed by soft X-ray photography. It was found that delamination growth behavior depended on the inter-laminer stress and the out-plane stress in thickness direction caused by free-edge effect. Quasi-isotropic, [45/0/-45/90]_s, laminates, are applied large peering stress at free edges of the specimen when the specimen is subjected to tensile stress. Therefore they showed edge delamination. On the other hands, cross-ply, [0/90_6]_s laminates, are applied large inter-laminer shear stress at transverse crack tips, and show local delamination originated by a transverse crack. Under the high-cycle loading, it was observed that depending on the applied stress level delamination growth behavior differed.

Effect of simvastatin on residual ridge resorption after tooth extraction

To observe the effect of simvastatin carried by poly (lactide-co-glycolide) (PLGA) on residual ridge resorption following tooth extraction. Sixty male Wistar rats were divided into experimental groups and control groups (30 rats/group). PLGA was immediately implanted with or without simvastatin into extraction sockets of the mandibular incisors. Soft X-ray photography, bone mineral density (BMD) and histopathologic study were conducted at 7, 14, 28, 56, and 84 days after implantation. The relative length values of residual alveolar ridge of the experimental groups were greater than those of the controls at 14, 28, 56, and 84 days after implantation, and there was a significant difference between the experimental and control groups (P < 0.05). The BMD of the specific region was higher in the experimental groups [(7.101 +/- 0.025), (7.178 +/- 0.039), and (7.162 +/- 0.052) g/cm(2)] than that in the control groups [(7.074 +/- 0.014), (7.117 +/- 0.012), and (7.059 +/- 0.037) g/cm(2)] (P < 0.05) after 28, 56, and 84 days. Light microscopy showed that bone formation rate and quality of the experimental group were better than those in the control group at the same time. Simvastatin carried by PLGA could induce bone formation of tooth socket. Local application of simvastatin would be potential to preserve the length and bone volume of alveolar ridge after tooth extraction.

Within-Stem Water Distribution in Living Trees Of Some Conifers

Water distributions within living stems of 11 species from three conifer families were observed with soft X-ray photography. The moisture contents at breast height of the trees were also measured. In all but one case, sapwood was almost saturated with free water. Intermediate wood, which was a narrow white band located between the sapwood and heartwood, was generally common in species with coloured heartwood. In heartwood, water distribution varied not only among species, but also within species, and even within a stem. In seven of the 11 species investigated, well-developed wetwood (the phenomenon of free water accumulated in heartwood) was observed. The frequent presence of wetwood led to the conclusion that it was a common feature in some groups of conifers. It is suggested that the view that wetwood is an abnormal feature may be incorrect because so far wetwood surveys have only focused on a few species that are important for forestry, e.g., hard pines. An extensive survey of many specimens belonging to various species is required to understand the mechanism of wetwood development.

Quantitative and qualitative influence on oral hard tissues of neonatal rats born to mothers given methamphetamine during pregnancy

We conducted research as part of a series of studies on the influence on various oral tissues of the offspring of mothers that were given methamphetamine (MA) during pregnancy. The mandibular strength during the growth process of newborn rats from mothers that had received MA was compared with normal newborns. Methamphetamine hydrochloride was continually administered to mother rats (MA group) every day from conception to the day before delivery. Observations of the newborn were made at birth, two, three, four and five weeks. Newborn rats from mothers who had been administered the same amount of physiological saline solution were used as controls. Peripheral quantitative computed tomography (pQCT) was used to measure bone strength to determine bone mineral density and bone structures. A complete determination was made after soft X-ray photography of the mandible. No significant difference was observed in mandibular growth from the menton to the gonion between the MA and the control groups throughout the experimental period. Although no difference was noted in trabecular bone, a significant difference was seen in cortical bone, which tended to become thinner in the MA group. In addition, the cortical bones in the MA group showed lower values for bone mineral density and bone mineral content compared with those in the control group. We concluded that the mandibular strength of neonatal rats of mothers that had received MA was weak, and could break easily compared with normal infants. These results indicate that the problems of female methamphetamine drug users extend to influence on the oral hard tissue formations of their offspring.

Life-history traits in insect inclusions associated with bamboo galls

Abstract We examined the life-history traits of insect inclusions in bamboo galls induced by the gall maker, Aiolomorphus rhopaloides Walker (Hymenoptera: Eurytomidae) in a bamboo stand. Eight hymenopteran and one dipteran species were detected using soft X-ray photography of the galls and insect emergence from the galls. Aiolomorphus rhopaloides was the gall maker and Diomorus aiolomorphi Kamijo (Torymidae) was its inquiline. Homoporus japonicus Ashmead (Pteromalidae) and Eupelmus sp. (Eupelmidae) are likely to be primary parasitoids of the larva of A. rhopaloides. Eurytoma sp. (Eurytomidae), Sycophila sp. (Eurytomidae) and Norbanus sp. (Pteromalidae) are thought to be facultative hyperparasitoids. Cecidomyiidae sp. is thought to be the inquiline of A. rhopaloides galls. Leptacis sp. (Platygastridae) probably parasitizes the larvae of Cecidomyiidae sp. Larvae of A. rhopaloides appeared in galls in July with the percentage of larvae decreasing in September, before overwintering as pupae. The growth of D. aiolomorphi larvae within galls may be faster than that of A. rhopaloides. The percentage of parasitoids in galls was low in July, but increased until winter. Aiolomorphus rhopaloides and D. aiolomorphi emerged from mid-April to early May, and from late April to early June, respectively. From overwintering galls, six other hymenopteran species emerged between late May and late June; one dipteran Cecidomyiidae sp. emerged between mid-April and early May.

Stem water transport of Lithocarpus edulis, an evergreen oak with radial-porous wood

The stem water conducting system of an evergreen broad-leaved oak, Lithocarpus edulis (Mak.) Nakai, was investigated. Evergreen broad-leaved oaks (Lithocarpus, Castanopsis, Cyclobalanopsis, Quercus) belonging to the Quercoideae are a major component of Asian monsoon forests, and are characterized by the possession of radial-porous wood. A characteristic of radial-porous wood is the development of aggregate rays between radially oriented files of vessels. We measured the distribution of vessel lumen diameters in a stem cross section and calculated the theoretical water conductivity of the wood. The radial profile of the heat pulse velocity (HPV) was measured for an intact whole tree under field conditions and compared with the theoretical distribution of water conductivity. Soft X-ray photographs of frozen stem sections indicated that most of the vessel lumina were filled with water, including those of vessels more than 20 years old. Even when vessels were relatively wide (lumen diameters > 100 microm), cavitation was negligible. The rate of water uptake from the cut stem base correlated closely with HPV (r = 0.96), and HPV closely reflected the mean volume flow per stem sectional area (SFVS) around the sensor probes. However, the ray tissue sharply inhibited heat transfer, and the positioning of the probes strongly affected the absolute value of HPV. It was also found that HPV more closely reflected the mean sap flow velocity in the vessels than did SFVS.

10104 擬似等方性CFRP積層板の高サイクル疲労特性(疲労およびき裂進展,OS10 先進材料の力学と強度)

This paper describes high-cycle fatigue characteristics of quasi-isotropic CFRP laminates [-45/0/45/90]_s to 10^8 cycles. To investigate the fatigue behavior in the high-life region, the fatigue tests were conducted with frequency of 100Hz since it's difficult to conduct its with 5Hz and the damage behavior of the specimen was observed with a microscope, a soft X-ray photography and a 3D ultrasonic inspection system. In this study, to evaluate quantitive characteristics of transverse crack propagation in the high-cycle region, the energy release rate associated with transverse crack growth to the width direction was calculated and the transverse crack growth to the width direction was evaluated based on a modified Paris-law approach.

ラット下顎切歯抜歯窩の治癒過程に関する研究

Prosthodontic treatment is difficult if the alveolar ridge is low or thin. To develop a method for alveolar ridge preservation after tooth extraction, we need an experimental model of a small animal, in which we can analyze the socket healing easily and quantitatively. The purpose of the present study was to establish such an experimental model. Ten weeks old male rats of Wistar strain were used. The edge of the right mandibular incisor was cut every three days three times and the incisor was extracted at three days after the final cut. The animals were sacrificed 0, 1, 2, 4, 8, 12 weeks after the extraction and the mandibles were dissected out. The length of the alveolar bone was measured on soft X-ray photographs and bone mineral content was measured with a dual energy X-ray absorptiometer (DEXA). Then, transverse sections of the alveolar bone were prepared. Periodic three-times cutting of the edge of the mandibular incisor made the extraction easy. Quantitative analyses of new bone formation in the socket and the resorption of the alveolar bone were possible with soft X-ray photography and DEXA. The histological findings corresponded well with the data from the soft X-ray photos and DEXA measurements. The present results demonstrated the possibility of simple and quantitative analyses of socket healing after the extraction of rat mandibular incisors. This experimental model would be useful for developing a method to prevent atrophy of the alveolar ridge after tooth extraction.