Response reduction factor of irregular RC buildings in Kathmandu valley

Most current seismic design includes the nonlinear response of a structure through a response reduction factor （R）. This allows the designer to use a linear elastic force-based approach while accounting for nonlinear behavior and deformation limits. In fact, the response reduction factor is used in modem seismic codes to scale down the elastic response of a structure. This study focuses on estimating the actual ＇R＇ value for engineered design/construction of reinforced concrete （RC） buildings in Kathmandu valley. The ductility and overstrength of representative RC buildings in Kathmandu are investigated. Nonlinear pushover analysis was performed on structural models in order to evaluate the seismic performance of buildings. Twelve representative engineered irregular buildings with a variety of characteristics located in the Kathmandu valley were selected and studied. Furthermore, the effects of overstrength on the ductility factor, beam column capacity ratio on the building ductility, and load path on the response reduction factor, are examined. Finally, the results are further analyzed and compared with different structural parameters of the buildings.

Seismic response reduction analysis of large chassis base-isolated structure under long-period ground motions

Long-period structures(e.g.Isolated structures)tend to produce pseudo-resonance with low frequency compo-nents of long-period ground motions,resulting in the increase in damage.Stiffness mutation occurs due to the set-back in the upper body of the large chassis structure.In the parts with stiffness mutation,the torsion effect caused by the tower is far greater than that of the chassis itself.In this study,a total of 273 ground motions are collected and then filtered into four types,including the near-field ordinary,near-field pulse,far-field ordinary,and far-field harmonic.An 8-degree(0.2 g)fortified large chassis base-isolated structure is established.Furthermore,ETABS program software is used to conduct nonlinear time history analysis on the isolation and seismic model under bi-directional earthquake ground motions.The comparison results show that the seismic isolation effect of the base-isolated structure under long-period ground motions is worse than that associated with ordinary ground motions when the seismic response reduction rate of the large base floor significantly decreases compared with that of the tower.When the inter-story displacement angle and the displacement of isolation layer of the chassis exceeds the limit of Code for Seismic Design of Buildings(GB 50011-2010),it is recommended to adopt composite seismic isolation technology or add limit devices.Under the condition of long-period ground motions,the base-isolated structure reduces the lateral-torsional coupling effect of the large chassis structure,while the torsion response of large chassis’top layer increases.Under long-period ground motions with the same acceleration peak,the response of the base-isolated structure increases much more than that of the seismic structure and the consideration of this impact is suggested to be added to the Code.

Study on Improvement of Seismic Performance of Transmission Tower Using Viscous Damper

The earthquake resistance of transmission tower has been often discussed from the viewpoint of reinforcing the foundation of steel tower, but there are also few studies considering the damping characteristics of the tower. This paper focuses on the viscous damper which has been adopted for seismic reinforcement of bridges in recent years. The purpose of this study is to improve the seismic performance of steel tower by giving the high damping to the tower. We construct a single tower model considering the influence of transmission line, and then simulate the vibration characteristics and seismic behavior of the tower by the eigenvalue analysis and the dynamic response analysis. The results show that the transmission tower with viscous damper can reduce its own response effectively and drastically. This research concludes that it is necessary to consider the extreme increase of steel tower＇s response depending on the seismic wave and the collapse of steel tower can be avoided by using the optimum damper in the design of the transmission tower.

Seismic Response of Magnetically Levitated House

This study explored the seismic response of a house supporting base sides with a polymeric displacement control material and by magnetically levitating the foundation base. In this paper, we explore the possibility and efficacy of a seismic-isolated detached house as described above from both a shaking table experiment of model and three-dimensional finite element analysis. The seismic-isolated model showed stable response and its acceleration response was significantly reduced compared to the base-fixed model in the shaking table test. Three-dimensional finite element analysis was possible to simulate the experimental results. In the seismic response analysis of a full-scale detached house, the seismic-isolated model showed response reduction and its residual displacement was smaller than that of the sliding-base isolation model.

A tactical nanomissile mobilizing antitumor immunity enables neoadjuvant chemo-immunotherapy to minimize postsurgical tumor metastasis and recurrence

Neoadjuvant chemotherapy has become an indispensable weapon against high-risk resectable cancers,which benefits from tumor downstaging.However,the utility of chemotherapeutics alone as a neoadjuvant agent is incapable of generating durable therapeutic benefits to prevent postsurgical tumor metastasis and recurrence.Herein,a tactical nanomissile(TALE),equipped with a guidance system(PD-L1 monoclonal antibody),ammunition(mitoxantrone,Mit),and projectile bodies(tertiary amines modified azobenzene derivatives),is designed as a neoadjuvant chemo-immunotherapy setting,which aims at targeting tumor cells,and fast-releasing Mit owing to the intracellular azoreductase,thereby inducing immunogenic tumor cells death,and forming an in situ tumor vaccine containing damage-associated molecular patterns and multiple tumor antigen epitopes to mobilize the immune system.The formed in situ tumor vaccine can recruit and activate antigen-presenting cells,and ultimately increase the infiltration of CD8^(+)T cells while reversing the immunosuppression microenvironment.Moreover,this approach provokes a robust systemic immune response and immunological memory,as evidenced by preventing 83.3%of mice from postsurgical metastasis or recurrence in the B16-F10 tumor mouse model.Collectively,our results highlight the potential of TALE as a neoadjuvant chemo-immunotherapy paradigm that can not only debulk tumors but generate a long-term immunosurveillance to maximize the durable benefits of neoadjuvant chemotherapy.

Synthesis of poly(ethylene glycol)-SS-poly(ε-caprolactone)-SS-poly(ethylene glycol)triblock copolymers via end-group conjugation and self-assembly for reductively responsive drug delivery

In this study,we describe a simple synthesis route to prepare triblock copolymers with disulfide-linkers,poly(ethylene glycol)-SS-poly(ε-caprolactone)-SS-poly(ethylene glycol)(PEG-SS-PCL-SS-PEG)for application in the reductively responsive release of doxorubicin(DOX).To synthesize PEG-SS-PCL-SS-PEG,two end-groups of PCL-diol were first modified with cystamine to introduce disulfide bonds and subsequently conjugated with PEG-NHS via carbodiimide chemistry.PEG-SS-PCL-SSPEG fabricated into polymeric micelles with stable structure and different nanoscale sizes via adjusting the PCL chain length,showing obvious reductive responsiveness and fast drug release of encapsulated DOX in the presence of glutathione(GSH).Moreover,DOX-loaded PEG-SS-PCL-SS-PEG micelles exhibited higher therapeutic efficacy than reduction-insensitive PEG-b-PCL micelles in vitro.Thus,end-groups conjugation is a simple and straightforward strategy to introduce intelligent responsiveness in biocompatible block copolymers and improve their therapeutic efficacy.