2,012 research outputs found

    The use of electrical discharge for ignition and control of combustion of solid propellants

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    As the first step of the study of the combustion control of solid propellants by electrical discharges, the effects of an arc discharge, which flows along the burning surface, on the burning rate and on the increase of enthalpy of the combustion product were investigated. For specially devised composite propellants, which are composed of Al and Teflon powders, it was shown that the combination can be controlled by an arc discharge; the combustion continues when the arc discharge is applied and is interrupted when the arc discharge breaks. In the present investigation, it was also shown that an arc discharge coupled with a high-frequency electrical discharge has potential as an effective ignition method for solid propellants. For the application of this type of combustion control to an ignitor for a solid propellant rocket motor or to a control rocket motor, this method lacks flexibility in the configuration scale and needs relatively high electric power at the present stage

    Notes on Some Carboniferous Corals from Taishaku District, Hiroshima Prefecture, Japan

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    This paper gives the results of investigations on corals, obtained from the Carboniferoes rocks of the Taishaku district, Hiroshima Prefecture, Japan, with special reference to their stratigraphic distribution and geological age. Lithostrotionella taishakuensis, n. sp., Stylidophyllum yokomizoi, n. sp. and Pseudoparona taisyakuana are described and illustrated in the last chapter

    Expanding the role of tachykinins in the neuroendocrine control of reproduction

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    Reproductive function is driven by the hormonal interplay between the gonads and brain–pituitary axis. Gonadotropin-releasing hormone (GnRH) is released in a pulsatile manner, which is critical for the attainment and maintenance of fertility; however, GnRH neurons lack the ability to directly respond to most regulatory factors, and a hierarchical upstream neuronal network governs its secretion. We and others proposed a model in which Kiss1 neurons in the arcuate nucleus (ARC), called as KNDy neurons, release kisspeptin (a potent GnRH secretagogue) in a pulsatile manner to drive GnRH pulses under the coordinated autosynaptic action of its cotransmitters, the tachykinin neurokinin B (NKB, stimulatory) and dynorphin (inhibitory). Numerous genetic and pharmacological studies support this model; however, additional regulatory mechanisms (upstream of KNDy neurons) and alternative pathways of GnRH secretion (kisspeptin independent) exist, but remain ill defined. In this aspect, attention to other members of the tachykinin family, namely substance P (SP) and neurokinin A (NKA), has recently been rekindled. Even though there are still major gaps in our knowledge about the functional significance of these systems, substantial evidence, as discussed below, is placing tachykinin signaling as an important pathway for the awakening of the reproductive axis and the onset of puberty to physiological GnRH secretion and maintenance of fertility in adulthood

    Farnesyl diphosphate synthase is involved in the resistance to zoledronic acid of osteosarcoma cells.

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    We recently demonstrated original anti-tumor effects of zoledronic acid (Zol) on osteosarcoma cell lines independently of their p53 and Rb status. The present study investigated the potential Zol-resistance acquired by osteosarcoma cells after prolonged treatment. After 12 weeks of culture in the presence of 1 microm Zol, the effects of high doses of Zol (10-100 microm) were compared between the untreated rat (OSRGA, ROS) and human (MG63, SAOS2) osteosarcoma cells and Zol-pretreated cells in terms of cell proliferation, cell cycle analysis, migration assay and cytoskeleton organization. Long-term treatment with 1 microm Zol reduced the sensitivity of osteosarcoma cells to high concentrations of Zol. Furthermore, the Zol-resistant cells were sensitive to conventional anti-cancer agents demonstrating that this resistance process is independent of the multidrug resistance phenotype. However, as similar experiments performed in the presence of clodronate and pamidronate evidenced that this drug resistance was restricted to the nitrogen-containing bisphosphonates, we then hypothesized that this resistance could be associated with a differential expression of farnesyl diphos-phate synthase (FPPS) also observed in human osteosarcoma samples. The transfection of Zol-resistant cells with FPPS siRNA strongly increased their sensitivity to Zol. This study demonstrates for the first time the induction of metabolic resistance after prolonged Zol treatment of osteosarcoma cells confirming the therapeutic potential of Zol for the treatment of bone malignant pathologies, but points out the importance of the treatment regimen may be important in terms of duration and dose to avoid the development of drug metabolic resistance

    Implications of Dorsalis Pedis Artery Anatomical Variants for Dorsal Midfoot Surgery

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    Background: The dorsalis pedis artery (DPA) usually branches into the arcuate artery (AA) from its lateral side which in turn crosses the bases of the lateral four metatarsals. The DPA then passes into the first interosseous space, where it divides into the first metatarsal artery and the deep plantar artery. In this study, we aimed to determine the extent of variation in the DPA and the distance between the AA and the tarsometatarsal (TMT) joint with the aim of reducing the risk of vascular complications arising from dorsal midfoot surgery. Methods: In 29 fresh cadaveric feet, we examined the course of the DPA and the distance between the AA and the TMT joint on computed tomography images with barium sulfate contrast. Results: The DPA was observed to have a standard course in 11 of the 29 cases (37.9%) but did not give rise to the AA and lateral tarsal artery or branches of the plantar arterial arch supplied the second to fourth metatarsal spaces in 10 of 29 cases (34.5%). The mean closest distance from the TMT joint to the AA at the second, third, and fourth metatarsal level in the sagittal plane was 11.4 mm, 14.6 mm, and 17.1 mm, respectively. Conclusions: We found substantial variation in the arterial anatomy of the DPA system across the dorsal midfoot

    Distances from the deep plantar arch to the lesser metatarsals at risk during osteotomy : a fresh cadaveric study

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    Background: The deep plantar arch is formed by anastomosis of the lateral and deep plantar arteries. Osteotomy of the lesser metatarsals is often used to treat metatarsalgia and forefoot deformity. Although it is known that some blood vessels supplying the lesser metatarsals are prone to damage during osteotomy, there is little information on the distances between the deep plantar arch and the three lesser metatarsals. The aims of this study were to identify the distances between the deep plantar arch and the lesser metatarsals and to determine how osteotomy could damage the arch. Methods: Enhanced computed tomography scans of 20 fresh cadaveric feet (male, n = 10; female, n = 10; mean age 78.6 years at the time of death) were assessed. The specimens were injected with barium via the external iliac artery, and the distance from the deep plantar arch to each lesser metatarsal was measured on axial and sagittal images. Results: The shortest distances from the deep plantar arch to the second, third, and fourth metatarsals in the axial plane were 0.5, 2.2, and 2.8 mm, respectively. The shortest distances from the distal epiphysis to a line passing through the deep plantar arch perpendicular to the longitudinal axis of the lesser metatarsal in the sagittal plane were 47.0, 45.7, and 46.4 mm, respectively, and those from the tarsometatarsal joint were 23.0, 21.0, and 18.6 mm. The deep plantar arch ran at the level of the middle third, within the proximal portion of this third in 11/20 (55.0%), 7/20 (35.0%), and 5/16 (31.2%) specimens, respectively, and at the level of the proximal third in 9/20 (45.0%), 13/20 (65.0%), and 11/16 (68.8%). Conclusions: Overpenetration into the medial and plantar aspect of the second metatarsal or the proximal and plantar aspect of the fourth metatarsal during shaft or proximal osteotomy could easily damage the deep plantar arch. Shaft or proximal osteotomy approximately 45–47 mm proximal to the distal epiphysis or 18–23 mm distal to the tarsometatarsal joint on the plantar aspect could interrupt blood flow in the deep plantar arch

    Stratigraphy and Geologic Structure of the Tsukumi Limestone Group

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    Tsukumi limestone group, distributed in the eastern part of Oita Prefecture, is a conspicuous member of the Chichibu Terrain of the Outer Zone of Southwest Japan. The stratigraphic succession of the group is in descending order as follows: Permian formations Upper formation Dolomitic, oolitic limestone Limestone conglomerate Middle formation Dark-grey or light-grey limestone, containing the Yabeina globosa faunule and Neoschwagerina-Waagenophyllum fauna. Limestone-conglomerate, containing the Neoschwagerina-Verbeekina faunule. Lower formation Black sandy shale and sandstone Grey limestone, yielding the Pseudoschwagerina-Pseudofusulina-Stylidophyllum fauna. Carboniferous formation Oolitic, grey limestone, containing the Fusulinella faunule. The group is covered by the so-called Aso welded-tuff, loam and gravel bed. The geologic structure of the Tsukumi limestone group in the Suisyozan area is characterized by the zonal arrangement of the limestone formations and intercalations, which seems to be a result from the deformation of synclinorium. The structure is modified by many strike-faults or subparallel ones which are accompanied with the conspicuous fault-zone composed of sheared blocks of limestone and sandy-shale. Many normal or slightly diagonal faults cut the structure mentioned. The Tsukumi limestone group is separated from the adjoining non-calcareous formations, the Okukawachi and the Kozono, by the manifest faults dipping northwardly or vertically.今村外治教授退官記念特集

    Gene expression profiling in rats with depressive-like behavior

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    Individual differences indicate stronger phenotypes than model animals especially in behavioral studies, and some animals show unexpected behaviors in control and animal model groups. High-throughput analysis including cDNA microarray analysis are more affected by individual differences, because more samples are needed to reduce the difference in multiple factor analysis than single factor analysis such as real-time PCR. We measured the depressive-like behavior of over 100 normal rats in the forced swimming test and selected the rats for control and depression group from them to minimize the individual difference using data of force swimming test. Here, we provided the detail of methods and quality control parameters for the cDNA microarray data. This dataset can reflect the increase of depressive-like behavior. The dataset is deposited in the gene expression omnibus (GEO), series GSE63377

    ケイタイガクテキ カンテン カラ ミタ セイタイ チョウセツ ブッシツ ノ ハタラキ

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    My initial research was focused on the nervous system and endocrine organs, and analyzed the neuroendocrinological mechanism of regulating biological systems by investigating the locations and functions of neurotransmitters and steroid-metabolizing enzymes using mainly morphological techniques. Research areas spread over several related fields including neural development, stress reaction, bone metabolism and anomalies of human anatomy. Based on a morphological viewpoint, my future research should be advanced to revise conventional ideas or to make novel discoveries

    Entry points of nutrient arteries at risk during osteotomy of the lesser metatarsals : a fresh cadaveric study

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    Background: Osteotomies of the lesser (second to fourth) metatarsals are often used to correct forefoot deformities. However, certain areas of the lesser metatarsals where arteries may be prone to damage during surgery, and the resulting nonunion and delayed union could cause serious problems. This study sought to identify the nutrient arteries of the lesser metatarsals and to determine how osteotomy could injure these vessels. Methods: Enhanced computed tomography scans of 21 ft (male, n = 10; female, n = 11; mean age 78.6 years at the time of death) were assessed. Twenty-one lower limbs in 21 cadaveric specimens were injected with barium via the external iliac artery, and the points at which the nutrient arteries entered the lesser metatarsals were identified on axial and coronal images. Results: Each nutrient artery entered the lateral or medial plantar aspect of the lesser metatarsal in the middle third (just proximal to the middle point of the metatarsal) or proximal third obliquely from a distal direction. The mean ± standard deviation (SD) distances from the dorsal plane of the second, third, and fourth metatarsals to the point of entry of the nutrient artery in the axial plane were 8.2 ± 1.5, 7.6 ± 1.2, and 7.6 ± 1.5 mm, respectively. The mean ± SD distances from the distal epiphysis to the point of entry of the nutrient artery into the second, third, and fourth metatarsals in the coronal plane were 3.3 ± 1.1, 3.1 ± 1.0, and 2.8 ± 1.2 mm, respectively. The mean ± SD distances from the distal epiphysis to the point of entry of the nutrient artery into the second, third, and fourth metatarsals in the coronal plane were 46.0 ± 5.2, 40.9 ± 2.6, and 39.1 ± 3.7 mm, respectively. The mean ± SD distances from the proximal epiphysis to the entry point of the nutrient artery into the second, third, and fourth metatarsals in the coronal plane were 23.8 ± 4.7, 25.8 ± 4.3, and 25.0 ± 3.2 mm, respectively. Conclusions: Distal metatarsal osteotomies might be safer than shaft or proximal osteotomy to avoid disruption of the nutrient artery, leading to delayed consolidation of the osteotomy and nonunion
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