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Search Results: 1 - 10 of 176 matches for " Hiroomi Okuyama "
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The Expression of Surfactant Proteins A and D in the Intestines and Pancreas of Murine Fetuses  [PDF]
Ryuta Saka, Hiroomi Okuyama, Kaoru Uchida, Kumiko Nakahira, Takashi Sasaki, Satoko Nose, Masahiro Nakayama, Masahiro Fukuzawa, Itaru Yanagihara
Open Journal of Pediatrics (OJPed) , 2014, DOI: 10.4236/ojped.2014.41002

Purpose: Surfactant proteins exist in the digestive tract and may play an important role in the host defense. However, the expression of surfactant proteins in the premature digestive system remains unclear. The aim of this study was to investigate the expression of surfactant proteins in the intes-tines and pancreas of murine fetuses. Methods: Immunostaining for SP-A and SP-D was assessed in the small intestine and pancreas of ICR murine fetuses on days 15, 16, 17 and 18 of gestation (normal duration of pregnancy: 19 - 21 days). RT-PCR was performed to detect the expression of spa and spd mRNA in the small intestine and pancreas on day 16, 17 and 18 of gestation. Results: Immunoreactivity for SP-A and SP-D in the

Numerical Analysis on Wood Pyrolysis in Pre-Vacuum Chamber  [PDF]
Hiroki Homma, Hiroomi Homma, Muhammad Idris
Journal of Sustainable Bioenergy Systems (JSBS) , 2014, DOI: 10.4236/jsbs.2014.43014

In the previous experimental work, a new technology system for wood pyrolysis was developed to aim at mitigating climate change, global warming, and energy crisis as well as enhancing low electrification in rural areas in developing countries. The new technology system equipped with a pre-vacuum chamber requires low cost and less maintenance. However, large wood pyrolysis in the pre-vacuum chamber is rather complicated. To obtain a good understanding of the previous experimental results, a numerical analysis taking account of heat-mass transfer and chemical reaction is carried out. Two-step general reaction model is proposed for the numerical analysis. The first stage is volatile and char formation from the wood pieces and the second state is decomposition of the volatile to five species including vapor of tar. In this analysis, chemical formulae of the volatile and the tar are successfully identified hypothetically. The results obtained by this numerical analysis can explain the experimental results reasonably and provide useful information about time evolution of volatile formation, temperature change in pre-vacuum chamber with time, and species mole concentration decomposed from the volatile.

Effects of Secondary Chamber on Gas Yield by Pre-Vacuum Chamber Pyrolysis of Rubber Wood  [PDF]
Hiroki Homma, Hiroomi Homma, Sihar Siahaan
Journal of Sustainable Bioenergy Systems (JSBS) , 2017, DOI: 10.4236/jsbs.2017.71001
Abstract: Global warming awareness criticizes further usage of fossil fuels and insists promotion of renewable energy usage. Additionally, many people in rural areas of developing countries cannot access electricity. To solve this sort of energy crisis including global warming, current authors developed a proto-type of a pyrolysis plant equipped with a prevacuum chamber, which can be used to produce combustible gases for an engine generator in rural areas where people cannot access electricity. The plant is simple and easily maintained in consideration of special conditions that a rural area can receive very few maintenance service, technical assistance, and supply of spare parts. However, gas yield obtained by the proto-type of plant was around 20 wt% of feedstock. One way to enhance gas yield from this proto-type of plant is to utilize reaction of secondary tar cracking. This research work aims to examine possibility of gas yield enhancement keeping a simple structure of the proto-type of plant and using a simple technique of secondary tar cracking. Two tar cracking methods are examined: one is homogeneous tar cracking and the other is heterogeneous tar cracking using catalysis. In the homogeneous tar cracking, pyrolysis gases must be heated up to 650oC to 700oC and in the heterogeneous tar cracking, wood char is used as catalysis, because wood char is byproduct of pyrolysis. It is concluded that the homogeneous tar cracking is quite unlikely in the secondary chamber, but on the other hand, heterogeneous tar cracking using wood char can produce 30 wt% of gas yield from 1 kg of feedstock.
Effects of Improving Public Services for Tourism Developments in Islands: The Case of Remote Islands in Nagasaki, Japan  [PDF]
Tadahiro Okuyama, Hayato Ishihara
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.36018
Abstract: Growths of numbers of tourists who stay long-term in tourism sites are an important policy for local governments in islands due to their locations that are far from urban areas. However, many tourists hesitate to stay long-term in islands owing to not only the expensive travel costs but also the lack of public services in islands. The purpose of this study is to examine effects of improving public services in islands for tourists’ willingness to pays (WTPs) and non-tourists’ attitudes for long-term stays. Data on tourism activity for islands, Nagasaki, Japan were used. Respondents were asked about their WTPs for long-term stays and their needs for public services of islands; reductions of costs for rent or purchasing houses for long-term stays and travel costs, easy to take a vacation, to enhance medical services, educational services and job search services. The logit model was used for estimations. Median and mean values of WTPs (per year) were calculated JPY 151,629 (USD 1184) and JPY 242,110 (USD 3008). Positive effects on five public services (without travel costs) were confirmed. For example, the median values of WTPs were increased to JPY 478,369 (USD 5943) when the medical services were improved, and JPY 1,484,704 (USD 18,446) when all public services were improved. The results showed that improvement of public services have the effect 1) to improve tourists’ benefits and 2) to change many non-tourists’ attitudes from the rejection of staying long term in islands to the acceptance. Thus, results indicate that it would be better for central and/or local governments in islands to enhance islands’ public services.
Wood Pyrolysis in Pre-Vacuum Chamber  [PDF]
Hiroki Homma, Hiroomi Homma, Yusrizal  , Muhammad Idris
Journal of Sustainable Bioenergy Systems (JSBS) , 2013, DOI: 10.4236/jsbs.2013.34033

Climate change, global warming, and energy crisis are critical issues to be solved urgently in a global framework. Alternative energy and renewable energy technologies must be quickly developed to be substituted for fossil fuels like oil, gases, and coal. USA, UE, and Japan invested huge budgets to develop biomass renewable energy technology. Their target is to develop a commercial base large-scaled plant. On the other hand, in developing countries, especially in rural areas, people who can access electricity is still less than 70%, To decelerate or prevent global warming and improve electrification in rural areas, a new technology for wood pyrolysis, which requires low manufacturing cost and less maintenance, and of which gases are directly applicable to the gas engine generator, is developed in a laboratory scale. This paper reports the performance of this new plant and effects of several parameters on the performance. It is concluded that the new technology is quite feasible in rural areas, and upgrading of the plant is easily possible.

Coffee Modulates the Function of Brain-Derived Neurotrophic Factor (BDNF) in Human Neuroblastoma SH-SY5Y Cells  [PDF]
Shota Kakio, Yosuke Nakazawa, Megumi Funakoshi-Tago, Hiroomi Tamura
Neuroscience & Medicine (NM) , 2015, DOI: 10.4236/nm.2015.64025
Abstract: Recent epidemiological studies showed that daily coffee consumption is associated with a lower risk for several neurological disorders such as Alzheimer’s disease and Parkinson’s disease; however, the molecular mechanisms responsible for the protective effect of coffee against neurological disorders have not been elucidated. As brain-derived neurotrophic factor (BDNF) promotes neuronal survival and protects against neuronal damage, we investigated the effects of coffee on BDNF signaling using human neuroblastoma SH-SY5Y cells. We found that brewed coffee exerted an inhibitory effect on the autophosphorylation of tropomyosin receptor kinase B (TrkB), a BDNF receptor. Additionally, coffee reduced the phosphorylation of Akt in BDNF-treated SH-SY5Y cells. Treatment with coffee did not affect the TrkB receptor on the cell surface. The major constituents of coffee, such as caffeine, caffeic acid, chlorogenic acid, and trigonelline had no effect on TrkB phosphorylation induced by BDNF. In addition, coffee reduced the BDNF-induced increase in BDNF gene expression and the neurite outgrowth promoted by BDNF. Our data suggest that the protective effect of coffee reported in epidemiological studies against neurological disorders may not be associated with BDNF signaling through TrkB.
On absolute generalized N"orlund summability of orthogonal series
Y. Okuyama
Tamkang Journal of Mathematics , 2002, DOI: 10.5556/j.tkjm.33.2002.161-166
Abstract: In this paper, we shall prove a general theorem which contains two theorems on the absolute N"orlund summability and the absolute Riesz summability of orthogonal series.
Keetai Meeru: Younger People's Mobile Written Communication in Japan
OKUYAMA, Yoshiko
Electronic Journal of Contemporary Japanese Studies , 2009,
Abstract: Mobile phone technology is rapidly permeating our everyday lives. In Japan, the mobile phone, or keitai, is considered an absolute necessity for work and personal use. The most frequent users of keitai are Japanese adolescents. This article describes the recent developments and characteristics of keitai meeru (e-mail via mobile phones), a popular form of communication amongst Japanese youth. The data presented here was derived from multiple sources: a survey taken of approximately 900 middle school, high school, and university students in the summer of 2006, interviews with teenage informants, and participant observations collected in 2006 and 2007. The main purpose of this study was to identify changes in the characteristics of keitai meeru reported in previous studies and to provide a more current perspective on school and gender-based differences in Japanese youth cyber communication. The study first highlights the findings of the quantitative data which include some statistically significant school- and gender-based differences in the frequency, purposes, and reasons for keitai meeru communication. The study then summarizes the informants' personal views in contrast to the perspectives of the surveyed adolescents.
Wess-Zumino Term in Tachyon Effective Action
Kazumi Okuyama
Physics , 2003, DOI: 10.1088/1126-6708/2003/05/005
Abstract: We show that the source of RR field computed from the boundary state describing the decay of a non-BPS brane is reproduced by a particular form of the Wess-Zumino term in the tachyon effective action. We also obtain a simple expression of the S-charge associated with rolling tachyons.
Ghost Kinetic Operator of Vacuum String Field Theory
Kazumi Okuyama
Physics , 2002, DOI: 10.1088/1126-6708/2002/01/027
Abstract: Using the data of eigenvalues and eigenvectors of Neumann matrices in the 3-string vertex, we prove analytically that the ghost kinetic operator of vacuum string field theory obtained by Hata and Kawano is equal to the ghost operator inserted at the open string midpoint. We also comment on the values of determinants appearing in the norm of sliver state.
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