WTC2005-64346 RAIL CORRUGATIONS CAUSED BY LOW COEFFICIENT OF FRICTION IN A SUBMARINE RAILWAY TUNNEL

ABSTRACT One of some types of rail corrugations is caused on railway rail surface in a submarine tunnel. It poses a large problem from the aspects of railway vehicle and railway track deterioration. In this paper, the mechanism of the rail corrugations was studied with the focus placed on roll-slip of wheel and rail interface. Traction and vertical force interacting between wheel and rail were investigated by a vehicle/track interaction model, and the coefficient of friction (COF) on rail surface was measured. Also, the rail surface was analysed with infrared to understand the chemical composition of surface layer influenced by salty and very humid atmosphere in the submarine tunnel. ß-FeOOH was found out as a cause of reducing COF on rail surface

Transplantation of vascular cells derived from human embryonic stem cells contributes to vascular regeneration after stroke in mice

<p>Abstract</p> <p>Background</p> <p>We previously demonstrated that vascular endothelial growth factor receptor type 2 (VEGF-R2)-positive cells induced from mouse embryonic stem (ES) cells can differentiate into both endothelial cells (ECs) and mural cells (MCs) and these vascular cells construct blood vessel structures in vitro. Recently, we have also established a method for the large-scale expansion of ECs and MCs derived from human ES cells. We examined the potential of vascular cells derived from human ES cells to contribute to vascular regeneration and to provide therapeutic benefit for the ischemic brain.</p> <p>Methods</p> <p>Phosphate buffered saline, human peripheral blood mononuclear cells (hMNCs), ECs-, MCs-, or the mixture of ECs and MCs derived from human ES cells were intra-arterially transplanted into mice after transient middle cerebral artery occlusion (MCAo).</p> <p>Results</p> <p>Transplanted ECs were successfully incorporated into host capillaries and MCs were distributed in the areas surrounding endothelial tubes. The cerebral blood flow and the vascular density in the ischemic striatum on day 28 after MCAo had significantly improved in ECs-, MCs- and ECs+MCs-transplanted mice compared to that of mice injected with saline or transplanted with hMNCs. Moreover, compared to saline-injected or hMNC-transplanted mice, significant reduction of the infarct volume and of apoptosis as well as acceleration of neurological recovery were observed on day 28 after MCAo in the cell mixture-transplanted mice.</p> <p>Conclusion</p> <p>Transplantation of ECs and MCs derived from undifferentiated human ES cells have a potential to contribute to therapeutic vascular regeneration and consequently reduction of infarct area after stroke.</p

Very Low Nucleation Rates of Glucose Isomerase Crystals under Microgravity in the International Space Station

In situ observation of the nucleation and growth of glucose isomerase (GI) crystals under microgravity was conducted using an optical microscope during the first flight of the Advanced Nano Step project undertaken in the International Space Station (ISS). Very low apparent nucleation rates (J’) of GI crystals in the solution and on the substrate of the growth container were confirmed compared with those on the ground. In particular, J’ of GI crystals in the solution were a few times lower than that on the substrate. The growth rates (R) of the {101} faces of GI crystals on the substrate and the apparent growth rates (R’) in the solution were measured. The very low nucleation rates allowed us to successfully measure R at a very high supersaturation region (up to ln(C/Ce) = 6), at which R cannot be measured on the ground

Augmentation of Neovascularizaiton in Hindlimb Ischemia by Combined Transplantation of Human Embryonic Stem Cells-Derived Endothelial and Mural Cells

BACKGROUND: We demonstrated that mouse embryonic stem (ES) cells-derived vascular endothelial growth factor receptor-2 (VEGF-R2) positive cells could differentiate into both endothelial cells (EC) and mural cells (MC), and termed them as vascular progenitor cells (VPC). Recently, we have established a method to expand monkey and human ES cells-derived VPC with the proper differentiation stage in a large quantity. Here we investigated the therapeutic potential of human VPC-derived EC and MC for vascular regeneration. METHODS AND RESULTS: After the expansion of human VPC-derived vascular cells, we transplanted these cells to nude mice with hindlimb ischemia. The blood flow recovery and capillary density in ischemic hindlimbs were significantly improved in human VPC-derived EC-transplanted mice, compared to human peripheral and umbilical cord blood-derived endothelial progenitor cells (pEPC and uEPC) transplanted mice. The combined transplantation of human VPC-derived EC and MC synergistically improved blood flow of ischemic hindlimbs remarkably, compared to the single cell transplantations. Transplanted VPC-derived vascular cells were effectively incorporated into host circulating vessels as EC and MC to maintain long-term vascular integrity. CONCLUSIONS: Our findings suggest that the combined transplantation of human ES cells-derived EC and MC can be used as a new promising strategy for therapeutic vascular regeneration in patients with tissue ischemia

WTC2005-64346 RAIL CORRUGATIONS CAUSED BY LOW COEFFICIENT OF FRICTION IN A SUBMARINE RAILWAY TUNNEL

ABSTRACT One of some types of rail corrugations is caused on railway rail surface in a submarine tunnel. It poses a large problem from the aspects of railway vehicle and railway track deterioration. In this paper, the mechanism of the rail corrugations was studied with the focus placed on roll-slip of wheel and rail interface. Traction and vertical force interacting between wheel and rail were investigated by a vehicle/track interaction model, and the coefficient of friction (COF) on rail surface was measured. Also, the rail surface was analysed with infrared to understand the chemical composition of surface layer influenced by salty and very humid atmosphere in the submarine tunnel. ß-FeOOH was found out as a cause of reducing COF on rail surface

Sirt1 plays an important role in mediating greater functionality of human ES/iPS-derived vascular endothelial cells.

OBJECTIVE: We previously succeeded in inducing and isolating vascular endothelial cells (ECs) from both human embryonic stem (ES) and induced pluripotent stem (iPS) cells. Here, we compared the functionality of human adult ECs (HAECs), human ES-derived ECs (ESECs) and human iPS-derived ECs (iPSECs). METHODS AND RESULTS: We compared the cell proliferative potential, potential for migration, and tolerance to oxidative stress. ESECs were significantly superior to HAECs in all of these cell functions. The cell functions of iPSECs were comparable to those of ESECSs and also superior to HAECs. We then analyzed the gene expressions of HAECs, ESECs and iPSECs, and observed that the expression level of Sirt1, a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase, is higher in ESECs and iPSECs than in HAECs. The inhibition of Sirt1 with a Sirt1-specific inhibitor and siRNA antagonized these differences between the three types of cells. CONCLUSIONS: Sirt1 plays a key role in the high cellular function of ESECs and iPSECs. Although further in vivo investigations are required, this study initially demonstrated the potential of ESECs and iPSECs as the cell source for regenerative medicine, and also showed the potential of ES cells as a useful tool for elucidating the molecular mechanism of cell aging

Highly Purified Glucose Isomerase Crystals Under Microgravity Conditions Grow as Fast as Those on the Ground Do

Suppression of convection flows (solute transportation) and of impurity incorporation into crystals seem to be the main reasons why the quality of protein crystals improves under microgravity, although their precise mechanisms have not been completely discovered yet. We tried to clarify effects of suppression of convection flows on crystallization processes by in-situ observation of straight steps on parallelogram-shaped spiral growth hillocks on the {110} faces of highly purified glucose isomerase (GI) crystals under microgravity conditions and on the ground. Lateral growth rates Vlateral of a spiral hillock on the {110} face of a glucose isomerase crystal in situ under microgravity and step velocities Vstep of the same configuration on the ground had similar maximum values. This similarity indicates the convection flow has a small, if any, influence on the growth rates of protein crystals, contrary to conventional expectations. From Vstep of the straight step in a particular direction, we calculated the vibrational frequency of a GI tetramer at a kink site of a step as (1182±3) s^(-1) with the assumption of zero activation energy of kink incorporation processes