573 research outputs found

    The role of high-speed rail in regional development

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (p. 175-178).by Hitoshi Ono.M.S

    Reconstruction of ancestral brains: Exploring the evolutionary process of encephalization in amniotes

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    AbstractThere is huge divergence in the size and complexity of vertebrate brains. Notably, mammals and birds have bigger brains than other vertebrates, largely because these animal groups established larger dorsal telencephali. Fossil evidence suggests that this anatomical trait could have evolved independently. However, recent comparative developmental analyses demonstrate surprising commonalities in neuronal subtypes among species, although this interpretation is highly controversial. In this review, we introduce intriguing evidence regarding brain evolution collected from recent studies in paleontology and developmental biology, and we discuss possible evolutionary changes in the cortical developmental programs that led to the encephalization and structural complexity of amniote brains. New research concepts and approaches will shed light on the origin and evolutionary processes of amniote brains, particularly the mammalian cerebral cortex

    The Effects of Molybdenum, Wolfram and Copper on the Solubility of Graphite in Liquid Iron and a Method for Calculation of the Activity Coefficient of Carbon in Multicomponent Alloys

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    The effects of molybdenum, wolfram and copper on the solubility of graphite in liquid iron have been studied at 1550°C. Interaction parameters at graphite saturation are given as follows : A general approximate equation for calculating the activity coefficient of carbon in a multicomponent alloy can be given as follows : The validity of this equation was discussed by using the present data. Interaction parameters for infinitely dilute and graphite saturated solutions were compared and discussed

    Settlement Fund Circulation Problem

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    In the economic activities, the central bank has an important role to cover payments of banks, when they are short of funds to clear their debts. For this purpose, the central bank timely puts funds so that the economic activities go smooth. Since payments in this mechanism are processed sequentially, the total amount of funds put by the central bank critically depends on the order of the payments. Then an interest goes to the amount to prepare if the order of the payments can be controlled by the central bank, or if it is determined under the worst case scenario. This motivates us to introduce a brand-new problem, which we call the settlement fund circulation problem. The problems are formulated as follows: Let G=(V,A) be a directed multigraph with a vertex set V and an arc set A. Each arc ain A is endowed debt d(a)ge 0, and the debts are settled sequentially under a sequence pi of arcs. Each vertex vin V is put fund in the amount of p_{pi}(v)ge 0 under the sequence. The minimum/maximum settlement fund circulation problem (Min-SFC/Max-SFC) in a given graph G with debts d: Arightarrow mathbb{R}_{+}cup {0} asks to find a bijection pi:Ato {1,2,dots,|A|} that minimizes/maximizes the total funds sum _{vin V}p_{pi }(v). In this paper, we show that both Min-SFC and Max-SFC are NP-hard; in particular, Min-SFC is (I) strongly NP-hard even if G is (i) a multigraph with |V|=2 or (ii) a simple graph with treewidth at most two,and is (II) (not necessarily strongly) NP-hard for simple trees of diameter four, while it is solvable in polynomial time for stars. Also, we identify several polynomial time solvable cases for both problems

    Premovement Silent Period of Erector Spinae and Reaction Times of Bulky Muscles in Ballistic Standing-up Movement

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    The appearance rate of premovement silent periods (PMSs) of the erector spinae and EMG-reaction times of the obliquus abdominis and quadriceps femoris were examined during fast ballistic standing-up movement in the normal adults and hemiplegics. The average appearance rate of PMSs in hemiplegics was lower than in normal subjects, but no significant laterality was observed in either groups. Reaction times of trunk muscles also showed no significant laterality in either the normal subjects or the hemiplegics. Considering the relation between the appearance rate of PMS and the motion velocity, the PMS did not seem to reflect the central processing efficacy itself, which can be evaluated by reaction time measurement. Electromyographic study of the PMS may provide an indicator of the central coordination mechanism of the trunk and extremities

    Immunohistochemistry of YAP and dNp63 and survival analysis of patients bearing precancerous lesion and oral squamous cell carcinoma

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    Background: Yes-associated protein (YAP) is a candidate oncogene in various human cancers, and recently, it has been reported that YAP expression and its activity was enhanced by Delta Np63. However, the role of YAP and Delta Np63 expression in carcinogenesis and progression of oral squamous cell carcinoma (OSCC) has been unknown. Therefore, we investigated how YAP and Delta Np63 influence carcinogenesis and progression of OSCC. Methods: We performed immunohistochemical analyses in whole tissue samples to investigate YAP and Delta Np63 expression in normal oral mucosa, epithelial hyperplasia, oral epithelial dysplasia (OED; low/high grade), carcinoma in situ (CIS), and OSCC. Furthermore, in OSCC, we analyzed clinical significance by using Kaplan-Meier survival analysis. Results: In normal oral mucosa and epithelial hyperplasia, YAP expression was primarily confined to the basal and parabasal layers, but YAP expression was elevated in OED, CIS, and OSCC. In OED, YAP and Delta Np63 expression levels were markedly higher in high grade than in low grade. In OSCC groups, YAP and Delta Np63 expression patterns tended to differ according to histopathological differentiation of OSCC. Furthermore, the YAP high expression group, which showed YAP staining in >50% positive cells with strong cytoplasmic staining or >10% positive cells with nuclear reactivity, showed a tendency to have a poor survival rate. Conclusion: YAP and Delta Np63 expression levels correlated with grade of oral OED. Additionally, YAP expression was associated with OSCC survival rate. Our results suggested that YAP and Delta Np63 expression might serve as predictive markers to distinguish OSCC development and progression

    Clinical study on primary screening of oral cancer and precancerous lesions by oral cytology

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    Background This study was conducted to compare the histological diagnostic accuracy of conventional oral-based cytology and liquid-based cytology (LBC) methods. Methods Histological diagnoses of 251 cases were classified as negative (no malignancy lesion, inflammation, or mild/moderate dysplasia) and positive [severe dysplasia/carcinoma in situ (CIS) and squamous cell carcinoma (SCC)]. Cytological diagnoses were classified as negative for intraepithelial lesion or malignancy (NILM), oral low-grade squamous intraepithelial lesion (OLSIL), oral high-grade squamous intraepithelial lesion (OHSIL), or SCC. Cytological diagnostic results were compared with histology results. Results Of NILM cytology cases, the most frequent case was negative [LBCn = 50 (90.9%), conventionaln = 22 (95.7%)]. Among OLSIL cytodiagnoses, the most common was negative (LBCn = 34; 75.6%, conventionaln = 14; 70.0%). Among OHSIL cytodiagnoses (LBCn = 51, conventionaln = 23), SCC was the most frequent (LBCn = 31; 60.8%, conventionaln = 7; 30.4%). Negative cases were common (LBCn = 13; 25.5%, conventionaln = 14; 60.9%). Among SCC cytodiagnoses SCC was the most common (LBCn = 16; 88.9%, conventionaln = 14; 87.5%). Regarding the diagnostic results of cytology, assuming OHSIL and SCC as cytologically positive, the LBC method/conventional method showed a sensitivity of 79.4%/76.7%, specificity of 85.1%/69.2%, false-positive rate of 14.9%/30.7%, and false-negative rate of 20.6%/23.3%. Conclusions LBC method was superior to conventional cytodiagnosis methods. It was especially superior for OLSIL and OHSIL. Because of the false-positive and false-negative cytodiagnoses, it is necessary to make a comprehensive diagnosis considering the clinical findings
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