Oxime bonds dispersed in the backbones of the synthetic polymers, while young in the current spectrum of the biomedical application, are rapidly extending into their own niche. In the present work, oxime linkages were confirmed to be a robust tool for the design of pH-sensitive polymeric drug delivery systems. The triblock copolymer (PEG-OPCL-PEG) consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic oxime-tethered polycaprolactone (OPCL) was successfully prepared by aminooxy terminals of OPCL ligating with aldehyde-terminated PEG (PEG-CHO). Owing to its amphiphilic architecture, PEG-OPCL-PEG self-assembled into the micelles in aqueous media, validated by the measurement of critical micelle concentration (CMC). The MTT assay showed that PEG-OPCL-PEG exhibited low cytotoxicity against NIH/3T3 normal cells. Doxorubicin (DOX) as a model drug was encapsulated into the PEG-OPCL-PEG micelles. Drug release study revealed that the DOX release from micelles was significantly accelerated at mildly acid pH of 5.0 compared to physiological pH of 7.4, suggesting the pH-responsive feature of the drug delivery systems with oxime linkages. Flow cytometry and confocal laser scanning microscopy (CLSM) measurements indicated that these DOX-loaded micelles were easily internalized by living cells. MTT assay against HeLa cancer cells showed DOX-loaded PEG-OPCL-PEG micelles had a high anticancer efficacy. All of these results demonstrate that these polymeric micelles self-assembled from oxime-tethered block copolymers are promising carriers for the pH-triggered intracellular delivery of hydrophobic anticancer drugs.

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SUMMARY The self‐centering prestressed concrete (SCPC) moment resisting frame (MRF) with web friction devices (WFDs) is a new type of structure that integrates advantages of post‐tensioned precast concrete MRFs and self‐centering steel MRFs. In this paper, the configuration of the connection and design guidelines are presented. To further reduce damage to the connection under cyclic loading and facilitate implementation in practice, several significant improvements are proposed and experimentally validated in this study, including the following: (i) the welded connection is replaced by the bolted connection; (ii) aluminum plates are used for friction instead of brass plates to reduce the material costs without decreasing the energy dissipation capacity; and (iii) post‐tensioned tendons at the corners of the beam are replaced by a bundle of tendons at the beam centroid in order to facilitate the field assembly. The resulting improvements of seismic performances are experimentally demonstrated by 10 cyclic tests of two full‐scale SCPC beam–column connections. Numerical simulation of the proposed connection is conducted using the Open System for Earthquake Engineering Simulation (OpenSees) to replicate the experimental results. Seismic behaviors are taken into account, such as the gap opening/closing at the beam–column interface, the self‐centering capacity, and the friction energy dissipation. Good agreement is observed between the numerical simulation and the test results. The proposed SCPC connection with bolted WFDs is demonstrated to have good performance when subjected to cyclic loading. Copyright © 2013 John Wiley & Sons, Ltd.

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This paper presents a new method for the nonlinear analysis of steel frames subject to fire and explosion loading conditions. The proposed method subsumes conventional nonlinear analysis in that it can be applied to the two cases of fire and explosion loading in isolation and, more significantly, within the same analysis. The resulting integrated approach can therefore be used to study the behaviour of steel members and frames subject to scenarios of explosion loading followed by fire, effectively enabling the influence of explosion on the fire resistance to be evaluated. The paper describes the component beam-column formulations and discusses their incorporation within an adaptive analysis framework, which is largely responsible for the considerable efficiency of the proposed method. Details of the required elasto-plastic material models are finally presented, including the adopted models for steel subject to elevated temperatures, creep and high strain-rates.The companion paper provides several verification and application examples, using the nonlinear analysis program ADAPTIC, which demonstrate the accuracy and efficiency of the proposed method, and which investigate the influence of explosion on the fire resistance of steel members and frames.

The companion paper presents a new adaptive method for integrated fire and explosion analysis of steel frames. This paper verifies the new developments, implemented within the nonlinear analysis program ADAPTIC, particularly against the results of experiments on steel members and frames subjected to fire. The benefits of adaptive nonlinear analysis are then highlighted by means of an example which demonstrates its computational superiority over conventional nonlinear analysis.Finally, parametric studies on column and frame configurations subject to the successive actions of explosion and fire are undertaken using the developed integrated analysis tool. The results of these preliminary studies indicate that the damage induced by moderate explosion loading can significantly influence the fire resistance of steel structures. Collectively, the capabilities and efficiency of the developed environment emphasise the important role that it can play in further studies aimed at generating design guidance.

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SUMMARYThis paper revisits the problem of robust stability analysis and synthesis for linear parameter varying (LPV) systems. By introducing two new slack variables, new conditions for the polyquadratic stability and for the affine quadratic stability of LPV systems are presented in terms of linear matrix inequalities. These results are then applied for robust controller synthesis. Owing to the extra freedom degree introduced by the real slack variable, this proposed approach could lead to less conservative results than that of from the literature, especially for robust controller synthesis. The effectiveness and superiority are demonstrated by the comparison between this proposed approach and the existing results on a well-known numerical example.