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This study develops and proposes a research approach founded on linking two novel theoretical frameworks for analysing and explaining relational strategies at intercultural workplace meetings, namely, the Multi-Level Model (MLM) and Cultural Self Perception (CSP). The approach is tested through a case study of a problematic meeting in an intercultural workplace in China. At this meeting, the Chinese and western expatriate participants both carefully adopted a range of relational strategies for problem talk. However, the interactions still evolved into a severe confrontation between the Chinese and expatriate participants. The cultural differences in relational strategies are explored on three levels, namely, tum-taking, speech act and situational context. The analysis indicates that while the relational strategies of the expatriate speakers can only be found on the speech act level, those of the Chinese speakers can be found on all of the three levels. Even on the speech act level, there are significant differences between the Chinese and expatriate speakers. It is argued that the communicative breakdown was caused by clashes of expectations of relational strategies for problem talk at meetings, and such differences can be explained by drawing on the framework of CSP. The investigation in this case study thus demonstrates that the combination of the frameworks of MLM and CSP can facilitate both systematic analysis of interactive strategies at different levels and in-depth understanding of the cultural roots for the choices of relational strategies at intercultural workplace meetings.

Development of dry powder inhaler (DPI) formulations for respiratory diseases, such as Tuberculosis (TB), is challenging. The major limitation of current marketed DPIs is low delivery efficiency. In addition, delivered dose variation is also a challenging problem in the development and design of DPI formulations due to the poor flowability and dispersibility of the powder formulation. Furthermore, antibiotic drugs used in TB or other respiratory infectious diseases have to be administered in a relatively large dose for pulmonary delivery. However, currently there is no high dose conventional lactose based DPI formulations available. Therefore, I propose an innovative approach to solve these problems through the engineering of particulate lactose by wet granulation. Lactose is the commonly used carrier particle for DPI formulations. Although it was widely believed that carrier particles with smaller diameters were preferable to maximize aerosolization efficiency (the ability of the drugs to be delivered to the lung), it was found recently that lactose carriers with large size also can improve aerosol performance, especially when combined with greater surface roughness and an appropriately designed inhaler device. In the first study, after the engineered particulate lactose was manufactured, the relationship between the physico-chemical properties, e.g. size, of the granulated lactose and the DPI aerosol performance was investigated. It was concluded that poorer or enhanced dispersion performance is not an inherent property to the significantly large size of granulated lactose carriers as previously contended. Relatively large granulated lactose has improved flowability and increased surface roughness with increasing size fraction, which were properties for formulating high drug loaded DPI formulations. It was found that the aerosol performance of the high drug loaded DPI formulation depended significantly on the specific APIs and also the inhalation flow rate used in the cascade impactor study. DPI aerosol performance is the interplay of formulation, patient inhalation effort and device design. The device design was therefore modified and optimized to further improve the aerosol performance. In the end, with the optimized device and granulated lactose as the carrier, a high drug loaded rifampicin DPI formulation with improved aerosol performance (fine particle fraction around 70%), better blending uniformity and potential low systemic toxicity was achieved.

Highly compliant, biocompatible polydimethylsiloxane (PDMS) micropillar (micro-cantilever) arrays have been used as a force transducer to measure the cellular contraction forces. The basic sensing principle of these devices relies on converting lateral deflections to corresponding reaction forces using appropriate beam bending models. While these micropillar-based force transducers have many benefits over previous methods, the time/frequency dependent modulus of PDMS materials and the low aspect ratio of micropillars greatly compromise accuracy in calculation of cellular forces and understanding of cellular response mechanism. In addition, recently there is an increasing demand to explore the multifunctionality of PDMS materials, such as electrical properties, besides the role of pure mechanical structural material. Adding conducting fillers into the PDMS matrix will enable the unique tunability in both mechanical and electrical properties for the composites. However, the phase separation and high volume fraction are two major issues that limit the practical applications. This dissertation addresses three critical technical issues for next-generation, high accuracy and tunable polymeric bio-transducers: 1) viscoelastic properties of PDMS, 2) force conversion models for micro-cantilever beams, and 3) mechanical and electrical properties characterization of PDMS and conducting polymer nanowire composites. This research provides a comprehensive characterization of the viscoelastic properties of PDMS, in the time domain (relaxation modulus) and frequency domain (complex modulus), using advanced nanoindentation techniques. Both theoretical models and experimental methodologies are presented to improve the extraction accuracy of viscoelastic properties. The viscoelastic moduli of PDMS are incorporated into analytical and numerical models to convert the micropillar deflections into corresponding forces. The models are ultimately utilized to calculate the loading rate and beating frequency dependent cellular contraction forces with improved accuracy. In addition, the electrical and mechanical properties of PDMS composites are systematically studied using impedance spectroscopy and nanoindentation techniques. The effect of conducting polymer nanowire concentration on the dielectric constant and elastic modulus of the composites is analyzed by appropriate model. This dissertation demonstrates a comprehensive method for viscoelastic characterization, modeling, and analysis associated with the bending behavior of PDMS micropillar arrays, providing a more in-depth and physically accurate conversion model for force measurement applications. The scientific insights from the in-depth study of the viscoelasticity of PDMS will contribute to the analysis of many other soft polymer materials at micro/nano scales commonly used in biomedical research.