Search results for: Hidetoshi Nakashima

Authors: Tatsuya Kato, Masanobu Nagata, Hidetoshi Nakashima, Kazunori Matsuo

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Localization of mobile robots are important tasks for developing autonomous mobile robots. This paper proposes a method to estimate positions of a mobile robot using an omnidirectional camera on the robot. Landmarks for points of references are set up on a field where the robot works. The omnidirectional camera which can obtain 360 [deg] around images takes photographs of these landmarks. The positions of the robots are estimated from directions of these landmarks that are extracted from the images by image processing. This method can obtain the robot positions without accumulative position errors. Accuracy of the estimated robot positions by the proposed method are evaluated through some experiments. The results show that it can obtain the positions with small standard deviations. Therefore the method has possibilities of more accurate localization by tuning of appropriate offset parameters.

Keywords: mobile robots, localization, omnidirectional camera, estimating positions

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Authors: Jun-ichi Ochiai, Itsuki Noda, Ryo Kanamori, Keiji Hirata, Hitoshi Matsubara, Hideyuki Nakashima

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We conducted exhaustive simulations for data assimilation and evaluation of service quality for various setting in a new shared transportation system, called SAVS. Computational social simulation is a key technology to design recent social services like SAVS as new transportation service. One open issue in SAVS was to determine the service scale through the social simulation. Using our exhaustive simulation framework, OACIS, we did data-assimilation and evaluation of effects of SAVS based on actual tax-use data at Tajimi city, Japan. Finally, we get the conditions to realize the new service in a reasonable service quality.

Keywords: on-demand bus sytem, social simulation, data assimilation, exhaustive simulation

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Authors: Keiji Komatsu, Hayato Maruyama, Ariyuki Kato, Atsushi Nakamura, Shigeo Ohshio, Hiroki Akasaka, Hidetoshi Saitoh

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Violet Sr–Al–O:Eu2+ phosphor particles were synthesized from a metal–ethylenediaminetetraacetic acid (EDTA) solution of Sr, Al, Eu, and particulate alumina via spray drying and sintering in a reducing atmosphere. The crystal structures and emission properties at 85–300 K were investigated. The composition of the violet Sr–Al–O:Eu2+ phosphor particles was determined from various Sr–Al–O:Eu2+ phosphors by their emission properties’ dependence on temperature. The highly crystalline SrAl12O19:Eu2+ emission phases were confirmed by their crystallite sizes and the activation energies for the 4f5d–8S7/2 transition of the Eu2+ ion. These results showed that the material identification for the violet Sr–Al–O:Eu2+ phosphor was accomplished by the low-temperature luminescence measurements.

Keywords: low temperature luminescence spectroscopy, material identification, strontium aluminates phosphor, emission properties

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Authors: Gabriela T. Nakashima, Ana Larissa S. Hansted, Gabriela B. Belini, Carlos R. Sette Jr, Hiroyuki Yamamoto, Fabio M. Yamaji

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The aim of this study was to determine the interference from contaminants in the characterization of sugarcane straw. The sugarcane straw was collected after the harvest and taken to the drying oven, and then it was crushed in the mill type Willey. Analyzes of ash contents and Klason lignin were done in triplicate and high heating value (HHV) in duplicate, according to ASTM standard. The results obtained for the sugarcane straw were 5.29% for ash content, 29.87% for Klason lignin and 17.67 MJ.kg-1 for HHV. Also, the material was analyzed by scanning electron microscope (SEM). The presence of contaminants was observed, such as silica. The high amount of contaminants in the samples may impact the results of analyzes, also raising its values, for example in the Klason lignin content. These contaminants can also adversely affect the quality of the biomass. Even using the standards is important to know what the purpose of the analysis and care mainly of sampling.

Keywords: biomass, bioenergy, residues, solid fuel

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Authors: Noritaka Shigei, Kazuto Matsumoto, Yoshiki Nakashima, Hiromi Miyajima

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Although Mobile Wireless Sensor Networks (MWSNs), which consist of mobile sensor nodes (MSNs), can cover a wide range of observation region by using a small number of sensor nodes, they need to construct a network to collect the sensing data on the base station by moving the MSNs. As an effective method, the network construction method based on Virtual Rails (VRs), which is referred to as VR method, has been proposed. In this paper, we propose two types of effective techniques for the VR method. They can prolong the operation time of the network, which is limited by the battery capabilities of MSNs and the energy consumption of MSNs. The first technique, an effective arrangement of VRs, almost equalizes the number of MSNs belonging to each VR. The second technique, an adaptive movement method of MSNs, takes into account the residual energy of battery. In the simulation, we demonstrate that each technique can improve the network lifetime and the combination of both techniques is the most effective.

Keywords: mobile sensor node, relay of sensing data, residual energy, virtual rail, wireless sensor network

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Authors: Keiji Komatsu，Tetsuo Sekiya, Ayumu Toyama, Atsushi Nakamura, Ikumi Toda, Shigeo Ohshio, Hiroyuki Muramatsu, Hidetoshi Saitoh

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Yttrium oxide (Y2O3) films have been successfully deposited with yttrium-ethylenediaminetetraacetic acid (EDTA･Y･H) complexes prepared by various milling techniques. The effects of the properties of the EDTA･Y･H complex on the properties of the deposited Y2O3 films have been analyzed. Seven different types of the raw EDTA･Y･H complexes were prepared by various commercial milling techniques such as ball milling, hammer milling, commercial milling, and mortar milling. The milled EDTA･Y･H complexes exhibited various particle sizes and distributions, depending on the milling method. Furthermore, we analyzed the crystal structure, morphology and elemental distribution profile of the metal oxide films deposited on stainless steel substrate with the milled EDTA･Y･H complexes. Depending on the milling technique, the flow properties of the raw powders differed. The X-ray diffraction pattern of all the samples revealed the formation of Y2O3 crystalline phase, irrespective of the milling technique. Of all the different milling techniques, the hammer milling technique is considered suitable for fabricating dense Y2O3 films.

Keywords: powder sizes and distributions, flame spray coating techniques, Yttrium oxide

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Authors: Keiko Naito, Y. Nakashima, S. Yamauchi, Y. Kunitani, Y. Ishigami, K. Numata, M. Mizobe, Y. Homma, J. Takahashi, T. Inoue, T. Shiga, H. Funakoshi

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Background: A presence of severe acidemia, defined as pH < 7.2, is common during endotracheal intubation for critically ill patients in the emergency department (ED). Severe acidemia is widely recognized as a predisposing factor for intubation failure. However, it is unclear that acidemic condition itself actually makes endotracheal intubation more difficult. We aimed to evaluate if a presence of severe acidemia before intubation is associated with the lower first attempt intubation success rate in the ED. Methods: This is a retrospective observational cohort study in the ED of an urban hospital in Japan. The collected data included patient demographics, such as age, sex, and body mass index, presence of one or more factors of modified LEMON criteria for predicting difficult intubation, reasons for intubation, blood gas levels, airway equipment, intubation by emergency physician or not, and the use of the rapid sequence intubation technique. Those with any of the following were excluded from the analysis: (1) no blood gas drawn before intubation, (2) cardiopulmonary arrest, and (3) under 18 years of age. The primary outcome was the first attempt intubation success rates between a severe acidemic patients (SA) group and a non-severe acidemic patients (NA) group. Logistic regression analysis was used to test the first attempt success rates for intubations between those two groups. Results: Over 5 years, a total of 486 intubations were performed; 105 in the SA group and 381 in the NA group. The univariate analysis showed that the first attempt intubation success rate was lower in the SA group than in the NA group (71.4% vs 83.5%, p < 0.01). The multivariate logistic regression analysis identified that severe acidemia was significantly associated with the first attempt intubation failure (OR 1.9, 95% CI 1.03-3.68, p = 0.04). Conclusions: A presence of severe acidemia before endotracheal intubation lowers the first attempt intubation success rate in the ED.

Keywords: acidemia, airway management, endotracheal intubation, first-attempt intubation success rate

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Authors: Y. Kunitani, Y. Nakashima, S. Yamauchi, Y. Ishigami, K. Naito, K. Numata, M. Mizobe, Y. Homma, J. Takahashi, T. Inoue, T. Shiga, H. Funakoshi

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Background: Japanese Spotted Fever (JSF) is one of the Rickettsial infections, caused by Rickettsia japonica, which is transmitted by ticks. JSF is seen in limited area, such as Japan and South Korea. Its clinical triad is rash, eschar and fever. It often shows leukocytopenia, thrombopenia, elevated transaminase and high C-reactive protein (CRP). Sometimes it can be life-threatening due to disseminated intravascular coagulation or multiple organ failure. Study Aim: The aim of this study is to describe the features of JSF, as this unique infection is rapidly growing in Japan. Methods: This is a case series of JSF from 2009 to 2016, in Mie Prefectural Hospital in Japan. We collected JSF cases, which were diagnosed by polymerase chain reaction (PCR) of the skin or blood serum, or the elevation of the antibody titer of paired blood samples. Results: There were 43 JSF patients (19 male, 24 female) with a median age of 71 years [IQR:65-80]. The median body temperature was 38.1°C[IQR: 37.5-39.0]. 95% had a rash, 67% had eschar and 50% had fever. The median WBC count was 6,700 [IQR: 5,750-8,200] and leukocytopenia was observed in only 7%. The median platelet count was 14x104 [IQR10x104-17x104], thrombopenia was observed in 65%. The median aspartate transaminase (AST) was 53 IU/L [IQR: 41-93]; the median alanine aminotransferase (ALT) was 34 IU/L [IQR: 24-54]; the median CRP was 10.4 mg/dL [IQR:7.2-13.9]; the median lactate dehydrogenase (LDH) was 352IU/L [IQR:282-451]. CRP and LDH were elevated in almost all of the patients. Median length of stay in hospital was 8 days [IQR: 6-11]. All patients were treated with tetracycline and quinolone on the day of the presentation. There was no fatality from JSF. Conclusion: The patients with JSF classically presents with eschar, rash and fever. However, in this study, the half of the patients were afebrile. Although JSF is not a common infectious disease worldwide, if the patient had previously visited Japan or South Korea and presented with rash and eschar with or without fever, we should consider JSF as a potential diagnosis.

Keywords: infectious disease, Japanese spotted fever, Rickettsial disease, Rickettsia japonica

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Authors: Tettey Afi Pamela, Sotaro Fujii, Hidetoshi Saito, Kawaii Koichiro

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Introduction: Organisms employ adaptive mechanisms when faced with any stressor or risk of being wiped out. This has made it possible for them to survive in harsh environmental conditions such as increasing temperature, low pH, and anoxia. Some of the mechanisms they utilize include the expression of heat shock proteins, synthesis of cryoprotectants, and anhydrobiosis. Heat shock proteins (HSPs) have been widely studied to determine their involvement in stress tolerance among various organism, of which chironomid species have been no exception. We examined the survival and expression of genes encoding five (5) heat shock proteins (HSP70, HSP67, HSP60, HSP27, and HSP23) from Chironomus sulfurosus larvae reared from 1st instar at 25°C, 30°C, 35°C, and 40°C. Results: The highest survival rate was recorded at 30°C, followed by 25°C, then 35°C. Only a small percentage of C. sulfurosus survived at 40°C (14.5%). With regards to HSPs expression, some HSPs responded to an increase in high temperature. The relative expression levels were lowest at 30°C for HSP70, HSP60, HSP27, and HSP23. At 25°C and 40°C, HSP70, HSP67, HSP60, HSP27, and HSP23 had the highest expression. At 35°C, all had the lowest expression. Discussion: The expression of heat shock proteins varies from one species to another. We designated the genes HSP 70, HSP 67, HSP 60, HSP 27, and HSP 23 genes based on transcriptome analysis of C. sulfurosus. Our study can be termed as a long-heat shock study as C. sulfurosus was reared from the first instar to the fourth instar, and this might have led to a continuous induction of HSPs at 25°C. 40°C had the lowest survival but highest HSPs expression as C. sulfurosus larvae had to utilize HSPs for sustenance. These results and future high-throughput studies at both the transcriptome and proteome level will improve the information needed to predict the future geographic distribution of these species within the context of global warming.

Keywords: chironomid, heat shock proteins, high temperature, heat shock protein expression

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Authors: Kenichi Yamahara, Makiko Ohshima, Shunsuke Ohnishi, Hidetoshi Tsuda, Akihiko Taguchi, Toshihiro Soma, Hiroyasu Ogawa, Jun Yoshimatsu, Tomoaki Ikeda

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We have previously reported the therapeutic potential of rat fetal membrane(FM)-derived mesenchymal stem cells (MSCs) using various rat models including hindlimb ischemia, autoimmune myocarditis, glomerulonephritis, renal ischemia-reperfusion injury, and myocardial infarction. In this study, 1) we isolated and characterized MSCs from human amnion and chorion; 2) we examined their differences in the expression profile of growth factors and cytokines; and 3) we investigated the therapeutic potential and difference of these MSCs using murine hindlimb ischemia and acute graft-versus-host disease (GVHD) models. Isolated MSCs from both amnion and chorion layers of FM showed similar morphological appearance, multipotency, and cell-surface antigen expression. Conditioned media obtained from amnion- and chorion-derived MSCs inhibited cell death caused by serum starvation or hypoxia in endothelial cells and cardiomyocytes. Amnion and chorion MSCs secreted significant amounts of angiogenic factors including HGF, IGF-1, VEGF, and bFGF, although differences in the cellular expression profile of these soluble factors were observed. Transplantation of human amnion or chorion MSCs significantly increased blood flow and capillary density in a murine hindlimb ischemia model. In addition, compared to human chorion MSCs, human amnion MSCs markedly reduced T-lymphocyte proliferation with the enhanced secretion of PGE2, and improved the pathological situation of a mouse model of GVHD disease. Our results highlight that human amnionand chorion-derived MSCs, which showed differences in their soluble factor secretion and angiogenic/immuno-suppressive function, could be ideal cell sources for regenerative medicine.

Keywords: amnion, chorion, fetal membrane, mesenchymal stem cells

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Authors: Yuji Fujino, Kazu Amimoto, Kazuhiro Fukata, Masahide Inoue, Hidetoshi Takahashi, Shigeru Makita

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Aim: Pusher behavior (PB) is a disorder in which stroke patients shift their body weight toward the affected side of the body (the hemiparetic side) and push away from the non-hemiparetic side. These patients often use further pushing to resist any attempts to correct their position to upright. It is known that the subcortical white matter lesion (SWML) usually correlates of gait or balance function in stroke patients. However, it is unclear whether the SWML influences PB. The purpose of this study was to investigate if the damage of SWML affects the severity of PB on acute stroke patients. Methods: Fourteen PB patients without thalamic or cortical lesions (mean age 73.4 years, 17.5 days from onset) participated in this study. Evaluation of PB was performed according to the Scale for Contraversive Pushing (SCP) for sitting and/or standing. We used modified criteria wherein the SCP subscale scores in each section of the scale were >0. As a clinical measurement, patients were evaluated by the Stroke Impairment Assessment Set (SIAS). For the depiction of SWML, we used T2-weighted fluid-attenuated inversion-recovery imaging. The degree of damage on SWML was assessed using the Fazekas scale. Patients were divided into two groups in the presence of SWML (SWML+ group; Fazekas scale grade 1-3, SWML- group; Fazekas scale grade 0). The independent t-test was used to compare the SCP and SIAS. This retrospective study was approved by the Ethics Committee. Results: In SWML+ group, the SCP was 3.7±1.0 points (mean±SD), the SIAS was 28.0 points (median). In SWML- group, the SCP was 2.0±0.2 points, and the SIAS was 31.5 points. The SCP was significantly higher in SWML+ group than in SWML- group (p<0.05). The SIAS was not significant in both groups (p>0.05). Discussion: It has been considered that the posterior thalamus is the neural structures that process the afferent sensory signals mediating graviceptive information about upright body orientation in humans. Therefore, many studies reported that PB was typically associated with unilateral lesions of the posterior thalamus. However, the result indicates that these extra-thalamic brain areas also contribute to the network controlling upright body posture. Therefore, SMWL might induce dysfunction through malperfusion in distant thalamic or other structurally intact neural structures. This study had a small sample size. Therefore, future studies should be performed with a large number of PB patients. Conclusion: The present study suggests that SWML can be definitely associated with PB. The patients with SWML may be severely incapacitating.

Keywords: pushing behavior, subcortical white matter lesion, acute phase, stroke

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Authors: Gabriela T. Nakashima, Elias R. D. Padilla, Joao L. Barros, Gabriela B. Belini, Hiroyuki Yamamoto, Fabio M. Yamaji

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Biochar can be an alternative to use sugarcane trash. Biochar is a solid material obtained from pyrolysis, that is a biomass thermal degradation with low or no O₂ concentration. Pyrolysis transforms the carbon that is commonly found in other organic structures into a carbon with more stability that can resist microbial decomposition. Biochar has a versatility of uses such as soil fertility, carbon sequestration, energy generation, ecological restoration, and soil remediation. Biochar has a great ability to retain water and nutrients in the soil so that this material can improve the efficiency of irrigation and fertilization. The aim of this study was to characterize biochar produced from sugarcane trash in three different pyrolysis temperatures and determine the lowest temperature with the high yield and carbon content. Physical characterization of this biochar was performed to help the evaluation for the best production conditions. Sugarcane (Saccharum officinarum) trash was collected at Corredeira Farm, located in Ibaté, São Paulo State, Brazil. The farm has 800 hectares of planted area with an average yield of 87 t·ha⁻¹. The sugarcane varieties planted on the farm are: RB 855453, RB 867515, RB 855536, SP 803280, SP 813250. Sugarcane trash was dried and crushed into 50 mm pieces. Crucibles and lids were used to settle the sugarcane trash samples. The higher amount of sugarcane trash was added to the crucible to avoid the O₂ concentration. Biochar production was performed in three different pyrolysis temperatures (200°C, 325°C, 450°C) in 2 hours residence time in the muffle furnace. Gravimetric yield of biochar was obtained. Proximate analysis of biochar was done using ASTM E-872 and ABNT NBR 8112. Volatile matter and ash content were calculated by direct weight loss and fixed carbon content calculated by difference. Porosity measurement was evaluated using an automatic gas adsorption device, Autosorb-1, with CO₂ described by Nakatani. Approximately 0.5 g of biochar in 2 mm particle sizes were used for each measurement. Vacuum outgassing was performed as a pre-treatment in different conditions for each biochar temperature. The pore size distribution of micropores was determined using Horváth-Kawazoe method. Biochar presented different colors for each treatment. Biochar - 200°C presented a higher number of pieces with 10mm or more and did not present the dark black color like other treatments after 2 h residence time in muffle furnace. Also, this treatment had the higher content of volatiles and the lower amount of fixed carbon. In porosity analysis, while the temperature treatments increase, the amount of pores also increase. The increase in temperature resulted in a biochar with a better quality. The pores in biochar can help in the soil aeration, adsorption, water retention. Acknowledgment: This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil – PROAP-CAPES, PDSE and CAPES - Finance Code 001.

Keywords: proximate analysis, pyrolysis, soil amendment, sugarcane straw

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Authors: Eiji Nakamachi, Ryota Sakiyama, Koji Yamamoto, Yusuke Morita, Hidetoshi Sakamoto

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The regeneration of injured central nerve network caused by the cerebrovascular accidents is difficult, because of poor regeneration capability of central nerve system composed of the brain and the spinal cord. Recently, new regeneration methods such as transplant of nerve cells and supply of nerve nutritional factor were proposed and examined. However, there still remain many problems with the canceration of engrafted cells and so on and it is strongly required to establish an efficacious treating method of a central nerve system. Blackman proposed the electromagnetic stimulation method to enhance the axonal nerve extension. In this study, we try to design and fabricate a new three-dimensional (3D) bio-reactor, which can load a uniform AC magnetic field stimulation on PC12 cells in the extracellular environment for enhancement of an axonal nerve extension and 3D nerve network generation. Simultaneously, we measure the morphology of PC12 cell bodies, axons, and dendrites by the multiphoton excitation fluorescence microscope (MPM) and evaluate the effectiveness of the uniform AC magnetic stimulation to enhance the axonal nerve extension. Firstly, we designed and fabricated the uniform AC magnetic field stimulation bio-reactor. For the AC magnetic stimulation system, we used the laminated silicon steel sheets for a yoke structure of 3D chamber, which had a high magnetic permeability. Next, we adopted the pole piece structure and installed similar specification coils on both sides of the yoke. We searched an optimum pole piece structure using the magnetic field finite element (FE) analyses and the response surface methodology. We confirmed that the optimum 3D chamber structure showed a uniform magnetic flux density in the PC12 cell culture area by using FE analysis. Then, we fabricated the uniform AC magnetic field stimulation bio-reactor by adopting analytically determined specifications, such as the size of chamber and electromagnetic conditions. We confirmed that measurement results of magnetic field in the chamber showed a good agreement with FE results. Secondly, we fabricated a dish, which set inside the uniform AC magnetic field stimulation of bio-reactor. PC12 cells were disseminated with collagen gel and could be 3D cultured in the dish. The collagen gel were poured in the dish. The collagen gel, which had a disk shape of 6 mm diameter and 3mm height, was set on the membrane filter, which was located at 4 mm height from the bottom of dish. The disk was full filled with the culture medium inside the dish. Finally, we evaluated the effectiveness of the uniform AC magnetic field stimulation to enhance the nurve axonal extension. We confirmed that a 6.8 increase in the average axonal extension length of PC12 under the uniform AC magnetic field stimulation at 7 days culture in our bio-reactor, and a 24.7 increase in the maximum axonal extension length. Further, we confirmed that a 60 increase in the number of dendrites of PC12 under the uniform AC magnetic field stimulation. Finally, we confirm the availability of our uniform AC magnetic stimulation bio-reactor for the nerve axonal extension and the nerve network generation.

Keywords: nerve regeneration, axonal extension , PC12 cell, magnetic field, three-dimensional bio-reactor

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