On Vortex-induced Oscillation of Bluff Bodies

This paper considers the classification of vortex-induced oscillations and the geometrical shape effects on them. The following points are considered : 1) the flow pattern around the section, 2) the relation between the onset critical reduced velocity and the critical reduced velocity which is defined as the reciprocal of the Strouhal Number and 3) the relation between the two onset critical reduced velocities of vortex-induced oscillations (in the heaving and the torsional mode). Also, an estimation of “the onset critical reduced velocity” and “the allowable amplitude concerning the fatigue failure of steel” of vortex-induced oscillation is described

State of the art and future prospect of maintenance and operation of road tunnel

Abstract: In Japan, road tunnels have increased in both total length and number, and there are some tunnels still in service that were completed more than 50 years ago. In order to maintain such tunnels efficiently with decreasing public funds, deformation of tunnels should be detected at an early stage, and appropriate measures taken at the right time. This paper describes the present status, problems, and future prospects for road tunnel maintenance in Japan

Remnant tissue enhances early postoperative biomechanical strength and infiltration of Scleraxis-positive cells within the grafted tendon in a rat anterior cruciate ligament reconstruction model.

When ruptured, ligaments and tendons have limited self-repair capacity and rarely heal spontaneously. In the knee, the Anterior Cruciate Ligament (ACL) often ruptures during sports activities, causing functional impairment and requiring surgery using tendon grafts. Patients with insufficient time to recover before resuming sports risk re-injury. To develop more effective treatment, it is necessary to define mechanisms underlying ligament repair. For this, animal models can be useful, but mice are too small to create an ACL reconstruction model. Thus, we developed a transgenic rat model using control elements of Scleraxis (Scx), a transcription factor essential for ligament and tendon development, to drive GFP expression in order to localize Scx-expressing cells. As anticipated, Tg rats exhibited Scx-GFP in ACL during developmental but not adult stages. Interestingly, when we transplanted the flexor digitorum longus (FDP) tendon derived from adult Scx-GFP+ rats into WT adults, Scx-GFP was not expressed in transplanted tendons. However, tendons transplanted from adult WT rats into Scx-GFP rats showed upregulated Scx expression in tendon, suggesting that Scx-GFP+ cells are mobilized from tissues outside the tendon. Importantly, at 4 weeks post-surgery, Scx-GFP-expressing cells were more frequent within the grafted tendon when an ACL remnant was preserved (P group) relative to when it was not (R group) (P vs R groups (both n = 5), p<0.05), and by 6 weeks, biomechanical strength of the transplanted tendon was significantly increased if the remnant was preserved (P vsR groups (both n = 14), p<0.05). Scx-GFP+ cells increased in remnant tissue after surgery, suggesting remnant tissue is a source of Scx+ cells in grafted tendons. We conclude that the novel Scx-GFP Tg rat is useful to monitor emergence of Scx-positive cells, which likely contribute to increased graft strength after ACL reconstruction