Effect of correlated colour temperature and illuminance levels on user's visual perception under LED lighting in Taiwan.

This study aimed to utilise the characteristics of light-emitting diode (LED) lighting, including the adjustable correlated colour temperature (CCT) and illuminance levels, to evaluate the effects of various CCT and illuminance level combinations on visual perception and their patterns under different lighting conditions. Five white light balances with different CCTs were created together with four levels of illuminance. Based on the patterns of visual perception, when the CCT increased with the illuminance levels, the participants' visual perception changed from dim, boring, and sleepy to intense, vivid, energetic, and bright. As the CCT decreased, the participants gradually perceived the lighting as warm and relaxing. As illuminance levels increased, dim and unpleasant feelings progressively changed to bright and pleasant ones. The study attempted to identify lighting combinations that can respond to different psychological needs and can be used as a guide in the future design of lighting equipment. Practitioner summary: Appropriate lighting conditions could aid individuals in increasing the quality of life. This study conducted an experiment to evaluate the effects of various correlated colour temperature and illuminance level combinations on visual perception by using LED lighting. The results showed the effect of the different lighting combinations on the visual perception of the participants. Abbreviation: LED: light-emitting diode; CCT: correlated colour temperature; K: Kelvin; lx: Lux; CIE: Commission Internationale de l'Eclairage; ANSI: American National Standards Institute.

Recurrent pregnancy loss: A summary of international evidence-based guidelines and practice.

BACKGROUND: Recurrent pregnancy loss (RPL) is defined as two or more pregnancy losses. It affects <5% of couples. There are many proposed causes; however, in a significant proportion of cases, the cause is unknown. OBJECTIVE: The aim of this paper is to provide a summary of the aetiology, investigations and management of RPL, which is based on the three most recent international guidelines on RPL (European Society of Human Reproduction and Embryology, 2017; American Society for Reproductive Medicine, 2012; and the Royal College of Obstetricians and Gynaecologists, 2011). DISCUSSION: Management of RPL should occur in a specialised clinic. Appropriate investigations include karyotyping of parents and products of conception, two-dimensional/three-dimensional ultrasonography with sonohysterography, thyroid function tests, and antibodies and testing for acquired thrombophilias. Management options encompass some lifestyle modifications for smoking, alcohol, illicit drug use and caffeine consumption. Acquired thrombophilias should be treated with unfractionated heparin and low-dose aspirin.