The acoustical characterization of clay pots in Ottoman architecture through experimental and numerical analysis.

In medieval age, clay pots are utilized as multi-functional building elements serving not only for structural and ventilative purposes but also for the improvement of the acoustic qualities of the space. Although the medieval usage of acoustic pots is vaguely connected with the acoustic vessels of Vitruvius, their employment is also interpreted as cavity resonators as in the case of Süleymaniye Mosque. The 16th century edifice designed by Sinan the Architect Laureate is a significant example among its European counterparts with 224 clay pots embedded into its central dome. The present work aims to discuss the contribution of clay pots in acoustics of historical edifices focusing on Süleymaniye Mosque. In this study, a clay pot sample employed in the mosque is reproduced and impedance tube measurements are held. The results are then compared with finite element model simulations carried out to examine the effective frequency range of the clay pots. Finally, the data acquired from numerical simulations and the experimental measurements are applied in ray tracing simulations. The final results reinforce the contribution of clay pots on the improvement of sound energy decay rate measured after the final restorations within the mosque with repaired pots.

Surface modification on acoustic wave biosensors for enhanced specificity.

Changes in mass loading on the surface of acoustic biosensors result in output frequency shifts which provide precise measurements of analytes. Therefore, to detect a particular biomarker, the sensor delay path must be judiciously designed to maximize sensitivity and specificity. B-cell lymphoma 2 protein (Bcl-2) found in urine is under investigation as a biomarker for non-invasive early detection of ovarian cancer. In this study, surface chemistry and biofunctionalization approaches were evaluated for their effectiveness in presenting antibodies for Bcl-2 capture while minimizing non-specific protein adsorption. The optimal combination of sequentially adsorbing protein A/G, anti-Bcl-2 IgG and Pluronic F127 onto a hydrophobic surface provided the greatest signal-to-noise ratio and enabled the reliable detection of Bcl-2 concentrations below that previously identified for early stage ovarian cancer as characterized by a modified ELISA method. Finally, the optimal surface modification was applied to a prototype acoustic device and the frequency shift for a range of Bcl-2 concentration was quantified to demonstrate the effectiveness in surface acoustic wave (SAW)-based detection applications. The surface functionalization approaches demonstrated here to specifically and sensitively detect Bcl-2 in a working ultrasonic MEMS biosensor prototype can easily be modified to detect additional biomarkers and enhance other acoustic biosensors.

A urinary Bcl-2 surface acoustic wave biosensor for early ovarian cancer detection.

In this study, the design, fabrication, surface functionalization and experimental characterization of an ultrasonic MEMS biosensor for urinary anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) detection with sub ng/mL sensitivity is presented. It was previously shown that urinary Bcl-2 levels are reliably elevated during early and late stages of ovarian cancer. Our biosensor uses shear horizontal (SH) surface acoustic waves (SAWs) on surface functionalized ST-cut Quartz to quantify the mass loading change by protein adhesion to the delay path. SH-SAWs were generated and received by a pair of micro-fabricated interdigital transducers (IDTs) separated by a judiciously designed delay path. The delay path was surface-functionalized with monoclonal antibodies, ODMS, Protein A/G and Pluronic F127 for optimal Bcl-2 capture with minimal non-specific adsorption. Bcl-2 concentrations were quantified by the resulting resonance frequency shift detected by a custom designed resonator circuit. The target sensitivity for diagnosis and identifying the stage of ovarian cancer was successfully achieved with demonstrated Bcl-2 detection capability of 500 pg/mL. It was also shown that resonance frequency shift increases linearly with increasing Bcl-2 concentration.