Visible Light Communication System Based on Software Defined Radio: Performance Study of Intelligent Transportation and Indoor Applications

In this paper, our first attempt at visible light communication system, based on software defined radio (SDR) and implemented in LabVIEW is introduced. This paper mainly focuses on two most commonly used types of LED lights, ceiling lights and LED car lamps/tail-lights. The primary focus of this study is to determine the basic parameters of real implementation of visible light communication (VLC) system, such as transmit speed, communication errors (bit-error ratio, error vector magnitude, energy per bit to noise power spectral density ratio) and highest reachable distance. This work focuses on testing various multistate quadrature amplitude modulation (M-QAM). We have used Skoda Octavia III tail-light and Phillips indoor ceiling light as transmitters and SI PIN Thorlabs photodetector as receiver. Testing method for each light was different. When testing ceiling light, we have focused on reachable distance for each M-QAM variant. On the other side, Octavia tail-light was tested in variable nature conditions (such as thermal turbulence, rain, fog) simulated in special testing box. This work will present our solution, measured parameters and possible weak spots, which will be adjusted in the future.

Passive Ceiling Light Disinfection System to Reduce Bioburden in an Intensive Care Unit

A ceiling-installed narrow spectrum (402–420 nm) bactericidal blue light disinfection system was installed in a large suburban medical intensive care unit (ICU) and evaluated for implementation feasibility and effectiveness in reducing environmental bioburden. Installation of 54 ceiling devices was accomplished at low cost and with minimal ICU process disruption. Postinstallation high-touch surface colony counts were significantly lower than preinstallation. Linear mixed modeling demonstrated a 21% average overall decrease in colony count after installation, with consistent reduction in colony counts starting from week 4 postinstallation. Automated technology is potentially more efficient in reducing environmental bioburden in the acute care setting compared with other bioburden reducing methods or can provide a robust compliment to manual cleaning.

Operation Field Illuminance in Dentistry

Dental treatment zone and operation field illuminance estimation were made in this study. Treatment zone illuminance was 500 lx under conventional fluorescent lamp based lighting and 1000 lx in a case of additional ceiling light use. Operation field illuminance under a dental operating light varied from 4000 lx to 14000 lx in dependence on an oral cavity zone and a patient position. The maximal illuminance level was achieved at upper incisors in a patient supine position, the minimal one was achieved at upper molars in patient upright position. Using of light emitting diode (LED) headlight increased the illuminance up to 2000 lx in average. The use of intraoral light sources provided adequate operating field illuminance in range (7000–18000) lx in molars area where illumination of dental operating light are not enough. The study results allow recommendation of ceiling lights and intraoral lights as additional light sources.

Influence of bilirubin photoisomers on unbound bilirubin measurement in clinical settings

Background Measured unbound bilirubin concentration is influenced by bilirubin photoisomers. Bilirubin photoisomers are produced even with only a slight light exposure, and clinical samples are inevitably exposed to light. The objective of the study was to evaluate the influence of bilirubin photoisomers on the measurement of unbound bilirubin using serum of jaundiced neonates during blue light phototherapy. Methods Five neonates treated with phototherapy for hyperbilirubinaemia were enrolled. The samples were taken 12 h after initiation of phototherapy. Samples were processed by irradiation with blue light, by indoor ceiling light, by both blue light and indoor ceiling light or shaded. Bilirubin subfractions, total bilirubin and unbound bilirubin were measured. Results Compared with the non-irradiated samples, the (EZ)-cyclobilirubin concentration and (ZE)-bilirubin/(ZZ)-bilirubin ratio significantly increased in the blue light-irradiated samples, the (ZE)-bilirubin/(ZZ)-bilirubin ratio significantly increased in the indoor ceiling light-irradiated samples, and the (EZ)-cyclobilirubin, (EZ)-bilirubin and (ZE)-bilirubin/(ZZ)-bilirubin ratio significantly increased in the samples irradiated with both lights. No change was noted in unbound bilirubin in any group. Conclusions We consider that changes in bilirubin photoisomers induced by light exposure during clinical practice do not influence the measured unbound bilirubin concentration.