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Dielectric spectroscopy was used to determine both the real (e 0 ) and imaginary (e 00 ) parts of dielectric permittivity of a novel material, a mixture of liquid crystal 5 Ã CB and Al 2 O 3 powder. The main objective was to investigate the influence of surface on the molecular dynamics of 5 Ã CB. The high-frequency process was related to the reorientation of molecules around their short axes, the same results obtained for bulk 5 Ã CB. We find an additional low-frequency relaxation processes. This process was attributed to the surface polarization (molecules anchoring themselves to surface of Al 2 O 3 particles). The crystallization kinetics of cholesteric liquid crystal (LC) to the metastable crystalline phase was also studied.

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The purpose of this study was to examine the accuracy of HR measurements by the PTN-104 sensor in comparison to the fingertip pulse oximeter, which is a photoplethysmographic sensor (PPG). Twelve healthy participants underwent the same protocol during a single visit. Measurements were taken after each participant completed an initial rest period of 5 minutes and after 1-minute of exercising comprising of 30 squats. Each subject had the PTN-104 sensor attached to the index finger and a fingertip pulse oximeter to the opposite one. When examining the data in aggregate, there was a strong correlation between the PTN-104 sensor and PPG for HR (r = 0.988) with a mean bias of −2.55 bpm (95 % LoA +5.0, −10.1). The PTN-104 sensor satisfied validity criteria for HR monitors, however, showed a lower accuracy for measurements at rest, which is surprising. Due to the noticed limitations, this study should be repeated with a larger group of subjects and the PTN-104 sensor should be compared to the gold standard method for measuring HR, which is ECG.