116 research outputs found

    MPC Builder for Autonomous Drive: Automatic Generation of MPCs for Motion Planning and Control

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    This study presents a new framework for vehicle motion planning and control based on the automatic generation of model predictive controllers (MPCs) named MPC Builder. In this framework, several components necessary for MPC, such as prediction models, constraints, and cost functions, are prepared in advance. The MPC Builder then generates various MPCs online in a unified manner according to traffic situations. This scheme enabled us to represent various driving tasks with less design effort than typical switched MPC systems. The proposed framework was implemented considering the continuation/generalized minimum residual (C/GMRES) method optimization solver, which can reduce computational costs. Finally, numerical experiments on multiple driving scenarios were presented.Comment: 8 pages, 9 figure

    Point-focusing monochromator crystal realized by hot plastic deformation of a Ge wafer

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    A point-focusing Johansson monochromator crystal prepared by hot-pressing a Ge single-crystal wafer is demonstrated. By using 333 diffraction, Cu Kα radiation was focused onto a small spot

    Stein Variational Guided Model Predictive Path Integral Control: Proposal and Experiments with Fast Maneuvering Vehicles

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    This paper presents a novel Stochastic Optimal Control (SOC) method based on Model Predictive Path Integral control (MPPI), named Stein Variational Guided MPPI (SVG-MPPI), designed to handle rapidly shifting multimodal optimal action distributions. While MPPI can find a Gaussian-approximated optimal action distribution in closed form, i.e., without iterative solution updates, it struggles with multimodality of the optimal distributions, such as those involving non-convex constraints for obstacle avoidance. This is due to the less representative nature of the Gaussian. To overcome this limitation, our method aims to identify a target mode of the optimal distribution and guide the solution to converge to fit it. In the proposed method, the target mode is roughly estimated using a modified Stein Variational Gradient Descent (SVGD) method and embedded into the MPPI algorithm to find a closed-form "mode-seeking" solution that covers only the target mode, thus preserving the fast convergence property of MPPI. Our simulation and real-world experimental results demonstrate that SVG-MPPI outperforms both the original MPPI and other state-of-the-art sampling-based SOC algorithms in terms of path-tracking and obstacle-avoidance capabilities. Source code: https://github.com/kohonda/proj-svg_mppiComment: 7 pages, 5 figure

    Noninvasive quantification of regional ventricular function in rats: Assessment of serial change and spatial distribution using ultrasound strain analysis

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    Background: The optimal method for quantitative assessment of regional ventricular function in rats remains unclear. The goal of this study was to investigate the use of ultrasonic strain rate (SR) and strain analysis in evaluating the serial change and spatial distribution of regional contractile function in rats. Methods: In all, 22 anesthetized rats underwent incremental dobutamine infusion (protocol 1) for assessment of serial change or underwent coronary ligation (protocol 2) for assessment of spatial distribution. For protocol 1, the serial change of systolic SR and strain during dobutamine was measured in the posterior myocardium on the short-axis view, and the systolic strain was compared with the percent change in wall thickening. For protocol 2, the spatial distribution of strain profile was analyzed in normal, peripheral ischemic, and central ischemic regions that were identified by myocardial contrast echocardiography. Results: In protocol 1, the incremental dobutamine infusion resulted in a gradual increase in peak systolic SR. In contrast, peak systolic strain increased with low-dose dobutamine but tended to decrease for higher doses of dobutamine. Further, the serial change of peak systolic strain corresponded to changes in percent change in wall thickening, but the strain values were always lower than percent change in wall thickening. In protocol 2, the strain profile indicated postsystolic thickening in the peripheral ischemic region and indicated systolic wall thinning in the central ischemic region. Conclusions: Ultrasonic determination of SR and strain is an accurate and noninvasive method of quantitation of the serial change and spatial distribution of regional contractile function in rats. Copyright 2005 by the American Society of Echocardiography.Hirano T, Asanuma T, Azakami R, Okuda K, Ishikura F, Beppu S. Noninvasive quantification of regional ventricular function in rats: assessment of serial change and spatial distribution using ultrasound strain analysis. J Am Soc Echocardiogr. 2005 Sep;18(9):907-12. doi: 10.1016/j.echo.2005.01.009

    Impact of the Coronary Flow Reduction at Rest on Myocardial Perfusion and Functional Indices Derived from Myocardial Contrast and Strain Echocardiography

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    Background: The severity of the coronary flow reduction that corresponds to myocardial perfusion and functional abnormalities remains unclear. We estimated the impact of various severities of flow-limiting coronary stenosis at rest on myocardial perfusion and functional indices from myocardial contrast echocardiography and tissue strain imaging and characterized the relationship between both the indices. Methods: Four levels of flow-limiting stenoses (slight, mild, moderate, severe) of the left circumflex coronary artery were examined in 10 open-chest dogs. In the left circumflex coronary artery area, plateau videointensity and time to plateau (TP) of the replenishment curve from myocardial contrast echocardiography were calculated for perfusion analysis, and peak systolic strain and postsystolic strain index (PSI) from tissue strain imaging were measured for functional analysis. Results: Plateau videointensity and peak systolic strain tended to decrease with increased severity of stenosis, although these differences did not reach the level of statistical significance. TP and PSI were significantly increased in the context of moderate (≥30-<50%) and severe (≥50%) flow reduction when compared to baseline values (TP, moderate 1.69 ± 0.20 and severe 1.77 ± 0.25 vs baseline 0.93 ± 0.17, P < .01, respectively; PSI, moderate 0.96 ± 0.15 and severe 1.28 ± 0.32 vs baseline 0.59 ± 0.18, P < .05 and P < .01, respectively). Further, TP and PSI were positively correlated with flow reduction (r = 0.81 and r = 0.84, P < .0001, respectively), and PSI was positively correlated with TP (r = 0.72, P < .0001). Conclusions: In contrast to conventional indices, such as plateau videointensity and peak systolic strain, novel indices, such as TP and PSI, were both able to detect 30% or greater coronary flow reduction at rest. © 2006 American Society of Echocardiography.Okuda K, Asanuma T, Hirano T, Masuda K, Otani K, Ishikura F, Beppu S. Impact of the coronary flow reduction at rest on myocardial perfusion and functional indices derived from myocardial contrast and strain echocardiography. J Am Soc Echocardiogr. 2006 Jun;19(6):781-7. doi: 10.1016/j.echo.2005.10.016

    Dysbindin Regulates the Transcriptional Level of Myristoylated Alanine-Rich Protein Kinase C Substrate via the Interaction with NF-YB in Mice Brain

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    BACKGROUND: An accumulating body of evidence suggests that Dtnbp1 (Dysbindin) is a key susceptibility gene for schizophrenia. Using the yeast-two-hybrid screening system, we examined the candidate proteins interacting with Dysbindin and revealed one of these candidates to be the transcription factor NF-YB. METHODS: We employed an immunoprecipitation (IP) assay to demonstrate the Dysbindin-NF-YB interaction. DNA chips were used to screen for altered expression of genes in cells in which Dysbindin or NF-YB was down regulated, while Chromatin IP and Reporter assays were used to confirm the involvement of these genes in transcription of Myristoylated alanine-rich protein kinase C substrate (MARCKS). The sdy mutant mice with a deletion in Dysbindin, which exhibit behavioral abnormalities, and wild-type DBA2J mice were used to investigate MARCKS expression. RESULTS: We revealed an interaction between Dysbindin and NF-YB. DNA chips showed that MARCKS expression was increased in both Dysbindin knockdown cells and NF-YB knockdown cells, and Chromatin IP revealed interaction of these proteins at the MARCKS promoter region. Reporter assay results suggested functional involvement of the interaction between Dysbindin and NF-YB in MARCKS transcription levels, via the CCAAT motif which is a NF-YB binding sequence. MARCKS expression was increased in sdy mutant mice when compared to wild-type mice. CONCLUSIONS: These findings suggest that abnormal expression of MARCKS via dysfunction of Dysbindin might cause impairment of neural transmission and abnormal synaptogenesis. Our results should provide new insights into the mechanisms of neuronal development and the pathogenesis of schizophrenia

    Application of Bio-Based Wrinkled Surfaces as Cell Culture Scaffolds

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    Microscopic surface architectures that can be easily manufactured have been in demand as mechano-structural cues for tissue engineering. Microscopic surface reliefs synthesized by wrinkling were expected as cell culture scaffolds for cell proliferation, control of cellular alignment and differentiation, and spheroid generation. We previously developed bio-based wrinkled films prepared via lignification-mimetic reactions and drying. Although these films are expected as a candidate for cell culture scaffolds, stability and morphology of the wrinkled surfaces in aqueous buffer solutions were not explored. Here, we investigate the surface morphologies of the wrinkled films in phosphate-buffered saline, and their application to 3T3 cell culture. The wrinkled film prepared with the immersion treatment at 40 °C maintained its wrinkled structure in phosphate-buffered saline even after five days, although the wrinkles were broadened by hydration of the skin layer. Interestingly, higher cell numbers were observed in the 3T3 cell culture using the wrinkled film than using flat film with the same surface composition. In addition, the high biocompatibility of the wrinkled film was confirmed by in vivo experiments. These results strongly encourage application of the wrinkled film as a mechano-structural cue. Studies of the advanced applications for the wrinkled films are now in progress

    OryzaExpress: An Integrated Database of Gene Expression Networks and Omics Annotations in Rice

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    Similarity of gene expression profiles provides important clues for understanding the biological functions of genes, biological processes and metabolic pathways related to genes. A gene expression network (GEN) is an ideal choice to grasp such expression profile similarities among genes simultaneously. For GEN construction, the Pearson correlation coefficient (PCC) has been widely used as an index to evaluate the similarities of expression profiles for gene pairs. However, calculation of PCCs for all gene pairs requires large amounts of both time and computer resources. Based on correspondence analysis, we developed a new method for GEN construction, which takes minimal time even for large-scale expression data with general computational circumstances. Moreover, our method requires no prior parameters to remove sample redundancies in the data set. Using the new method, we constructed rice GENs from large-scale microarray data stored in a public database. We then collected and integrated various principal rice omics annotations in public and distinct databases. The integrated information contains annotations of genome, transcriptome and metabolic pathways. We thus developed the integrated database OryzaExpress for browsing GENs with an interactive and graphical viewer and principal omics annotations (http://riceball.lab.nig.ac.jp/oryzaexpress/). With integration of Arabidopsis GEN data from ATTED-II, OryzaExpress also allows us to compare GENs between rice and Arabidopsis. Thus, OryzaExpress is a comprehensive rice database that exploits powerful omics approaches from all perspectives in plant science and leads to systems biology

    A novel biomarker TERTmRNA is applicable for early detection of hepatoma

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    <p>Abstract</p> <p>Backgrounds</p> <p>We previously reported a highly sensitive method for serum human telomerase reverse transcriptase (hTERT) mRNA for hepatocellular carcinoma (HCC). α-fetoprotein (AFP) and des-γ-carboxy prothrombin (DCP) are good markers for HCC. In this study, we verified the significance of hTERTmRNA in a large scale multi-centered trial, collating quantified values with clinical course.</p> <p>Methods</p> <p>In 638 subjects including 303 patients with HCC, 89 with chronic hepatitis (CH), 45 with liver cirrhosis (LC) and 201 healthy individuals, we quantified serum hTERTmRNA using the real-time RT-PCR. We examined its sensitivity and specificity in HCC diagnosis, clinical significance, ROC curve analysis in comparison with other tumor markers, and its correlations with the clinical parameters using Pearson relative test and multivariate analyses. Furthermore, we performed a prospective and comparative study to observe the change of biomarkers, including hTERTmRNA in HCC patients receiving anti-cancer therapies.</p> <p>Results</p> <p>hTERTmRNA was demonstrated to be independently correlated with clinical parameters; tumor size and tumor differentiation (P < 0.001, each). The sensitivity/specificity of hTERTmRNA in HCC diagnosis showed 90.2%/85.4% for hTERT. hTERTmRNA proved to be superior to AFP, AFP-L3, and DCP in the diagnosis and underwent an indisputable change in response to therapy. The detection rate of small HCC by hTERTmRNA was superior to the other markers.</p> <p>Conclusions</p> <p>hTERTmRNA is superior to conventional tumor markers in the diagnosis and recurrence of HCC at an early stage.</p
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