A Novel Contact-Free Atrial Fibrillation Monitor- A Pilot Study

Aims Atrial fibrillation (AF) is a major cause of morbidity and mortality. Current guidelines support performing ECG screenings to spot atrial fibrillation in high-risk patients. The purpose of this study was to validate a new algorithm aimed to identify AF in patients measured with a recent FDA-cleared contact-free optical device. Methods and results Study participants were measured simultaneously using two devices: a contact-free optical system that measures chest motion-vibrations (investigational device, “Gili”) and a standard reference bed-side ECG monitor (Mindray®). Each reference ECG was evaluated by two board certified cardiologists that defined each trace as: regular rhythm, atrial fibrillation, other irregular rhythm or indecipherable/missing. A total of 3582, 30-sec intervals, pertaining to 444 patients (41.9% with a history of AF) were made available for analysis. Distribution of patients with active AF, other irregular rhythm and regular rhythm was 16.9%, 29.5% and 53.6% respectively. Following application of cross-validated machine learning approach, the observed sensitivity and specificity were 0.92 (95% CI: 0.91-0.93) and 0.96 (95% CI: 0.95-0.96) respectively. Conclusions This study demonstrates for the first time the efficacy of a contact-free optical device for detecting atrial fibrillation.

An integrated device for fast and sensitive immunosuppressant detection

The present paper describes a compact point of care (POC) optical device for therapeutic drug monitoring (TDM). The core of the device is a disposable plastic chip where an immunoassay for the determination of immunosuppressants takes place. The chip is designed in order to have ten parallel microchannels allowing the simultaneous detection of more than one analyte with replicate measurements. The device is equipped with a microfluidic system, which provides sample mixing with the necessary chemicals and pumping samples, reagents and buffers into the measurement chip, and with integrated thin film amorphous silicon photodiodes for the fluorescence detection. Submicrometric fluorescent magnetic particles are used as support in the immunoassay in order to improve the efficiency of the assay. In particular, the magnetic feature is used to concentrate the antibody onto the sensing layer leading to a much faster implementation of the assay, while the fluorescent feature is used to increase the optical signal leading to a larger optical dynamic change and consequently a better sensitivity and a lower limit of detection. The design and development of the whole integrated optical device are here illustrated. In addition, detection of mycophenolic acid and cyclosporine A in spiked solutions and in microdialysate samples from patient blood with the implemented device are reported. Graphical abstract

The Refractive Periscope – a Novel Concept

A periscope is an optical device whose function is to allow sighting of objects that are not in direct line of sight with the observer Eye/Screen/Detector. The concept behind the periscope is tilting the optical axis by breaking the rays of light with a mirror or prism so that the image is obtained in the desired location. The periscope has a variety of uses, many of which belong to the military realm. For example, observing from submarines above the sea level surface, looking at the war zone from inside of a tank, directing light into hidden places and more. In this article, the authors will review a new development based on wave guide concept which composes a tube with light reflective walls. This allows us to build a significantly Small-dimensional periscope with respect to a standard periscope that does not use lenses. The authors will also review a number of applications suitable for the reflection periscope.

Multifunctional Optical Device with a Continuous Tunability over 500 nm Spectral Range Using Polymerized Cholesteric Liquid Crystals

We report that polymerization makes a robust, practically applicable multifunctional optical device with a continuous wavelength tunable over 500 nm spectral range using UV-polymerizable cholesteric liquid crystals (CLCs). It can be used as a circular polarizer generating an extremely high degree of circularly polarized light with |g| = 1.85~2.00. It can also be used for optical notch filters, bandwidth-variable (from ~28 nm to ~93 nm) bandpass filters, mirrors, and intensity-variable beam splitters. Furthermore, this CLC device shows excellent stability owing to the polymerization of CLC cells. Its performance remains constant for a long time (~2 years) after a high-temperature exposure (170 °C for 1 h) and an extremely high laser beam intensity exposure (~143 W/cm2 of CW 532 nm diode laser and ~2.98 MW/cm2 of Nd: YAG pulse laser operation for two hours, respectively). The optical properties of polymerized CLC were theoretically analyzed by Berreman’s 4 × 4 matrix method. The characteristics of this device were significantly improved by introducing an anti-reflection layer on the device. This wavelength-tunable and multifunctional device could dramatically increase optical research efficiency in various spectroscopic works. It could be applied to many instruments using visible and near-infrared wavelengths.