Side-chain pyrene functional poly(vinyl alcohol) (PVA) was synthesized by using ''click chemistry'' strategy. First, partial tosylation of PVA with p-toluene sulfonyl chloride were performed. The resulting PVA-Ts polymer was then quantitatively converted into poly(vinyl alcohol)-azide (PVA-N 3 ) in the presence of NaN 3 /DMF at 60 C. Propargyl pyrene was prepared independently as a photoactive click component. Finally, azido functionalized PVA was coupled to propargyl pyrene with high efficiency by click chemistry. Incorporation of pyrene functionality in the resulting polymer was confirmed by spectral analysis. It is also shown that pyrene functionalized PVA (PVA-Py) exhibited characteristic fluorescence properties and improved solubility in highly polar solvents such as water, DMSO, and DMF as well as less polar solvent such as THF compared with pristine PVA. V

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When a solute is injected into a straight circular tube through which a solvent is in steady laminar flow it spreads out longitudinally under the combined effect of molecular diffusion and advection with the flow. Taylor (1953) showed that, provided there is no density difference between the solute and the solvent, the distribution of mean concentration satisfies a diffusion equation with a certain longitudinal diffusivity for large times and with respect to axes moving with the discharge velocity. In the present paper it is shown by a general argument that this statement remains true if the pipe is uniformly curved. An expression is given for the diffusivity, valid when the radius of curvature is sufficiently large. For all common liquids and most gases the diffusivity is reduced by the curvature. The rest of the paper deals with the effects of buoyancy forces caused by a density difference between the solute and the solvent, when the tube is horizontal. It is shown that in general a longitudinal diffusivity does not exist and an equation is derived that replaces the diffusion equation if the effects of buoyancy are small. A prediction from this equation is that buoyancy should not have a noticeable effect on the longitudinal dispersion for Péclet numbers near a certain value at which the two opposing influences of horizontal spreading due to gravity and lateral mixing due to secondary flow are in balance. This prediction is consistent with some observations made by Reejhsinghani, Gill & Barduhn (1966).

In the past decade, extensive research on dielectric properties of biological tissues led to characterization of dielectric property discrepancy between the malignant and healthy tissues. Such discrepancy enabled the development of microwave therapeutic and diagnostic technologies. Traditionally, dielectric property measurements of biological tissues is performed with the well-known contact probe (open-ended coaxial probe) technique. However, the technique suffers from limited accuracy and low loss resolution for permittivity and conductivity measurements, respectively. Therefore, despite the inherent dielectric property discrepancy, a rigorous measurement routine with open-ended coaxial probes is required for accurate differentiation of malignant and healthy tissues. In this paper, we propose to eliminate the need for multiple measurements with open-ended coaxial probe for malignant and healthy tissue differentiation by applying support vector machine (SVM) classification algorithm to the dielectric measurement data. To do so, first, in vivo malignant and healthy rat liver tissue dielectric property measurements are collected with open-ended coaxial probe technique between 500 MHz to 6 GHz. Cole-Cole functions are fitted to the measured dielectric properties and measurement data is verified with the literature. Malign tissue classification is realized by applying SVM to the open-ended coaxial probe measurements where as high as 99.2% accuracy (F1 Score) is obtained.

In this study, a novel pillar[5]arene-quinoline (P5-Q) as an organic material is used to fabricate Langmuir-Blodgett (LB) thin films and its organic vapor sensing properties have been investigated. The LB deposition process is characterized by UV-visible spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM) and quartz crystal microbalance (QCM) techniques. The typical frequency shift per layer is obtained as 31.75 Hz per layer and the deposited mass onto a quartz crystal is calculated to be 539.69 ng per layer (2.03 ng mm). The fitted surface plasmon resonance (SPR) data were utilized to calculate the film thickness of this material. The thickness of a single layer is calculated to be 1.26 ± 0.09 nm. QCM and SPR systems are used to investigate gas sensing performance of macrocyclic LB films during exposure to Volatile Organic Compounds (VOCs). The macrocyclic LB thin films are more sensitive to dichloromethane than that of other vapors used in this study. The sensitivity and detection limit performance of the P5-Q QCM sensor to dichloromethane vapor were calculated to be 14.751 Hz ppm and 0.203 ppm, respectively. These results demonstrated that the P5-Q material is promising as an organic vapor sensing device at room temperature. Despite Langmuir-Blodgett being a traditional technique in colloid and interface science, this study presents the first gas sensor application for pillararene LB films. Because of the unique symmetric pillar architecture of P5-Q, self-assembly of pillar[5]arene molecules should afford various characteristic nanometer-scale architectures such as micelles, vesicles, and tubes.

The Quartz Crystal Microbalance (QCM) system is utilized to investigate the relationship between mass uptake and associated swelling for Langmuir-Blodgett (LB) organic thin films obtained from pyrene endcapped polystyrene (PS). The study was carried out using three different molecular weights of polymeric chains. The changes in resonance frequency associated with mass changes can be attributed to the swelling behavior of polymeric thin films during vapor absorption. This swelling is due to the capturing of organic vapor molecules in the sensor environment. To quantify real-time QCM data for swelling, early-time Fick's law of diffusion was adopted to fit the results, and a good linear relationship was observed between the mass uptake and square root of the swelling time. The diffusion coefficients for swelling were thus obtained from the slopes of the fitting curves and was found to be correlation with the amount of organic vapor content in the cell. It was also observed that diffusion of the organic vapor into higher molecular weight polystyrene thin films are much faster than low molecular weight ones in sensor applications. Diffusion coefficients were found to be 0.2-3.0 Â 10 À16, 5.0-13 Â 10 À16, and 1.0-1.6 Â 10 À15 cm 2 /s for PS1, PS2, and PS3 LB thin films, respectively.

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