Time filter

Source Type

Science, Japan

Yamagata K.,Nihon University | Yamagata K.,NihonUniversity | Yamamoto M.,Nihon University | Kawakami K.,The University of Shimane | And 2 more authors.
Neuroscience | Year: 2014

In stroke-prone spontaneously hypertensive rats (SHRSP/Izm), ischemia induces swelling of astrocytes, a process that subsequently leads to neuronal death. Following ischemic insult, arginine vasopressin (AVP) can induce edema and l-serine released by astrocytes supports the survival of neuronal cells. The purpose of this study was to examine whether AVP contributed to the regulation of l-serine production following ischemic stroke. Here, we used cultured astrocytes from SHRSP/Izm rats and Wistar Kyoto rats (WKY/Izm) to examine whether AVP changed the production of l-serine and/or altered gene expression levels of the neural amino acid transporter (. Slc1a4), 3-phosphoglycerate dehydrogenase (. Phgdh) and serine racemase (. SRR). Furthermore, using astrocytes from the congenic rat SHRpch1_18 strain having quantitative trait loci (QTL) of stroke, we examined expression of those genes under conditions of hypoxia and reoxygenation (H/R). The expression levels of ASCT1 protein, the genes described above and l-serine levels were determined by Western blotting (WB), RT-PCR, real-time quantitative RT-PCR and HPLC. AVP increased the production of l-serine and the expression of Slc1a4 in WKY/Izm and SHRSP/Izm astrocytes. The production of l-serine and the expression of Slc1a4 were lower in SHRSP/Izm than in WKY/Izm cells. This difference was not seen with Phgdh. In the SHRpch1_18 strain, the expression of Slc1a4 and Phgdh significantly decreased after H/R. AVP-mediated enhanced expression of ASCT1 was blocked by the addition of bumetanide. These results suggest that the AVP-mediated attenuated expression of ASCT1 in astrocytes is associated with reduced l-serine production in SHRSP/Izm astrocytes. We hypothesize that reduction of gene expression by AVP might be related to the induction of stroke in the SHRpch1_18 rat strain. © 2014 IBRO.

Ishimaru S.,I2S2 Co. | Hata I.,Nihon University | Mikami J.,NihonUniversity | Kimiduka M.,I2S2 Co.
Journal of Structural and Construction Engineering | Year: 2010

This paper presents a simple design method for tuned dynamic mass systems (T.D.M.S.) consisted of dynamic mass-viscous damper-spring devices. The systems are designed by the law of geometric mean as a tuning rule, which is derived from the properties of the invariant point theory. The paper indicates that performance of the structure basically depends on the auxiliary stiffness factor which is the ratio of the stiffness of the devices to that of the main structure. And it also shows that the structures with T.D.M.S. can easily hold viscous damping factors more than 0.20 for the 1s t and 2 n d modes, when the auxiliary stiffness factor is controlled more than 0.25.

An experiment on the growing and harvesting of willow trees aimed at short rotation forestry was conducted in northern Japan. Willows were harvested using a sugarcane harvester from southern Japan during its agricultural off-season. The growing experiment showed the high potential of willow plantations to produce woody biomass of more than 10 dry-t/ha/y. The harvesting experiment showed that space for turning around, one line in one row as a planting method, a growing cycle of three years, and an extractor fan in the harvester are necessary for mechanical harvesting. Mechanical harvesting was considered to have little influence on willow regeneration provided that the machine cut reasonably well-grown trees. The system performance of harvesting and collecting willow billets in a hypothetical model field was calculated as 22.4 m3/h, suggesting the feasibility of supplying low-cost wood chips.

Discover hidden collaborations