A damper system that absorbs energy over a wide range of displacement amplitudes during building vibration was proposed. This system uses a serial connection of a metallic yielding component and viscoelastic damper with a displacement limit mechanism. Three types of the system were developed and tested: a diagonal bracing type, inverted V bracing type, and wall type. The test results showed that all these systems have damping ratios higher than 8% at small vibration amplitudes on the order of 0.1 mm. For a large vibration, a displacement limit mechanism with two pins limited the displacement of the viscoelastic damper as designed. Analytical simulations established that the system reduced the acceleration and the story drift to 60-70% and 80%, respectively, during a small earthquake compared with a conventional metallic yielding damper system. Furthermore, it showed an equivalent control performance during a severe earthquake. The damper system requires that a clearance be maintained for the displacement limit mechanism. However, this may be lost through construction error, residual displacement after an earthquake, and temperature effects. The changes in the clearance due to these effects were discussed.Corrugated steel plates have a high shear buckling strength; therefore, they need little stiffening. Multiple VE dampers were installed between the shear panel and beam of the building [26].The 'wall type' was applied in a 21-story steel hotel and office building complex in Hiroshima.
Dynamic loading test for VE damperA full-scale VE damper was tested during small vibrations, which are expected to affect human comfort. Figure 11 shows the test specimen. The VE material is the same as that used in the bracing types. This was a double-layered shear-type damper in which each layer consisted of 2.0-mm-thick press-vulcanized rubber adhered to steel plates. In the center of the VE damper, one stopper pin penetrated the damping layers. The diameters of the pin and the hole in the steel plates were 56 and 60 mm, respectively. It should be noted that the pin was fixed to the inner plate, whereas the pins of the bracing types were not fixed to any plates. In this system, when the displacement of the VE damper reaches 2 mm (0-p), the pin touches the outer steel plates and begins to restrict the displacement. This specimen was tested using a 50-kN dynamic loading test machine. The base of the inner plates was fixed to the reaction base of the machine, and the outer plates on the actuator head of the machine were guided by a linear motion rail. Two specimens were tested. Figure 10. Test results during quasi-static loading whose amplitude was gradually increased until story drift reached 23 mm. Figure 11. Test specimen of viscoelastic (VE) damper of 'wall type'.
This study is an evaluation of the effect of gastrointestinal cancer chemotherapy with short‐term periodic steroid premedication on bone metabolism. Primary endpoints were changes in bone mineral densities and metabolic bone turnover 16 weeks after initiation of chemotherapy.
ObjectiveFew data regarding the incidence of cancer-associated thromboembolism (TE) are available for Asian populations. We investigated the incidence of TE (TEi) and its risk factors among gastric and colorectal cancer (GCC) patients received chemotherapy in a daily practice setting.DesignA retrospective cohort study.SettingA single-institutional study that used data from Sapporo City General Hospital, Japan, on patients treated between January 2008 and May 2015.ParticipantsFive hundred Japanese GCC patients who started chemotherapy from January 2008 to May 2015.Primary and secondary outcome measuresTE was diagnosed by reviewing all the reports of contrast-enhanced CT performed during the follow-up period. All types of thrombosis detected by CT or additional imaging tests, such as venous TE, arterial TE and cerebral infarction, were defined as TE. Medical records of all identified patients were reviewed and potential risk factors for TE, including clinicopathological backgrounds, were collected. We defined the following patients as ‘active cancer’; patients with unresectable advanced GCC, cancer recurrence during or after completing adjuvant chemotherapy and/or presence of other malignant tumours.ResultsOf the 500 patients, 70 patients (14.0%) developed TE during the follow-up period. TEi was 9.2% and 17.3% in GCC patients, 18.1% and 3.5% in active and non-active cancer patients, and 24.0% and 12.9% in multiple and single primary, respectively. Multivariate logistic regression analysis showed that colorectal cancer (CRC) (OR 2.371; 95% CI 1.328 to 4.233), active cancer (OR 7.593; 95% CI 2.950 to 19.543) and multiple primary (OR 2.527; 95% CI 1.189 to 5.370) were independently associated with TEi.ConclusionTEi was 14.0% among Japanese GCC patients received chemotherapy, and was significantly higher among patients with CRC, active cancer and multiple primary than among those with gastric cancer, non-active cancer and single primary, respectively.Trial registration numberUMIN000018912.
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