We report observations of saturation effects in a Ce:LuAG and Eu-doped nitride ceramic phosphor for conversion of blue laser light for white light generation. The luminous flux from the phosphors material increases linearly with the input power until saturation effects limit the conversion. It is shown that the temperature of the phosphor layer influences the saturation power level and the conversion efficiency. It is also shown that the correlated color temperature (CCT), phosphor conversion efficiency and color rendering index (CRI) are dependent both on the incident power and spot size diameter of the illumination. A phosphor conversion efficiency up to 140.8 lm/W with CRI of 89.4 was achieved. The saturation in a ceramic phosphor, when illuminated by high intensity laser diodes, is estimated to play the main role in limiting the available luminance from laser-based lighting systems.

The overuse of antibiotics is accelerating the bacterial resistance, and therefore there is a need to reduce the amount of antibiotics used for treatment. Here, we demonstrate in vitro that specific wavelengths in a narrow range around 296 nm are able to eradicate bacteria in the biofilm state (grown for 24 hours) more effectively, than antibiotics and the combination of irradiation and antibiotics is even better, introducing a novel concept light assisted antibiotics. The investigated wavelength range was 249 nm to 338 nm with an approximate step of 5 nm. The novel concept that consists of a UV irradiation treatment followed by a tobramycin treatment can significantly reduce the amount of antibiotics needed for eradicating mature bacterial biofilms. The efficiency of the proposed light assisted antibiotics method was compared to combinatory antibiotic treatment and highly concentrated antibiotic monotherapy. The eradication efficacies, on mature biofilms, achieved by light assisted antibiotic and by the antibiotic monotherapy at approximately 10-fold higher concentration, were equivalent. The present achievement could motivate the development of light assisted antibiotic treatments for treating infections.

Since few foods are naturally rich in vitamin D, novel food products with a high content of vitamin D are needed to decrease the prevalence of vitamin D deficiency. Pork cracklings are Danish snacks with high contents of protein and fat. They are consumed mostly during wintertime when sun exposure cannot fulfil human needs for vitamin D₃. Pork cracklings were produced in an industrially friendly manner from UVB LED illuminated pork rind, using a combination of sous vide (85 °C, 60 min) and roasting in the oven (200 °C, 20 min). Thermal processing resulted in a significant loss of vitamin D₃ (>90%). Thus, the process was optimized by the UVB exposure of pork cracklings, i.e., after thermal processing. The produced pork cracklings had a vitamin D₃ level of ~10 µg/100 g, with a possibility of tailoring its final content. Furthermore, the fat content at 15–20% was a reduction of 50% compared to marketed products in 2021. No significant difference was found in the content of vitamin D₃ during 31 days of storage in the air. A consumer preference test (n = 53) indicated that >80% of participants liked the product and saw its potential as a new food source of vitamin D₃.

Background: Retrospective studies conducted in psychiatric wards have indicated a shorter duration of stay for depressed inpatients in bright compared to dim daylight-exposed rooms, pointing to a possible antidepressant effect of daylight conditions. Dynamic LED lighting, aiming to mimic daylight conditions, are currently been installed in several hospitals, but their feasibility is poorly investigated. Methods: To investigate the feasibility of these systems, we developed and installed a LED-lighting system in four rooms in a psychiatric inpatient ward. The system could function statically or dynamically regarding light intensity and colour temperature. The system consisted of (A) a large LED luminaire built into the window jamb mimicking sunlight reflections, (B) two LED light luminaires in the ceiling and (C) a LED reading luminaire. In the static mode, the systems provided constant light from A and B. In the dynamic mode, the system changed light intensity and colour temperature using A, B and C. Patients with unipolar or bipolar depression were randomised to dynamic or static LED lighting for 4 weeks, in addition to standard treatment. Primary outcome was the rate of patients discontinuing the trial due to discomfort from the lighting condition. Secondary outcomes were recruitment and dropout rates, visual comfort, depressive symptoms and suicidal ideation. Results: No participants discontinued due to discomfort from the LED lighting. Recruitment rate was 39.8%, dropout from treatment rates were 56.3% in the dynamic group and 33.3% in the static group. 78.1% in the dynamic group were satisfied with the lighting compared with 71.8% in the static group. Discomfort from the light (glare) was reported by 11.5% in the dynamic group compared to 5.1% in the static group. Endpoint suicidal scores were 16.8 (10.4) in the dynamic and 16.3 (14.9) in the static group. The lighting system was 100% functional. The light sensor system proved unstable. Conclusion: Dropout from treatment was high primarily due to early discharge and with a lack of endpoint assessments. The feasibility study has influenced an upcoming large-scale dynamic lighting efficacy trial where we will use a shorter study period of 3 weeks and with more emphasis on endpoint assessments. The lighting was well tolerated in both groups, but some found intensity too low in the evening. Thus, we will use higher intensity blue-enriched light in the morning and higher intensity amber (blue-depleted) light in the evening in the upcoming study. The light sensor system needs to be improved Trial registration: ClinicalTrials.gov: NCT03363529

The overuse of antibiotics is accelerating the bacterial resistance, and therefore there is a need to reduce the amount of antibiotics used for treatment. Here, we demonstrate that specific wavelengths in a narrow range around 296 nm are able to eradicate bacteria in the biofilm state more effectively, than antibiotics and the combination of irradiation and antibiotics is even better, introducing a novel concept light assisted antibiotics . The investigated wavelength range was 249 nm to 338 nm with an approximate step of 5 nm. The novel concept can significantly reduce the amount of antibiotics needed for eradicating mature bacterial biofilms. The irradiation treatment was combined with tobramycin and its efficiency was compared to combinatory antibiotic treatment and highly concentrated antibiotic monotherapy. The eradication efficacies, on mature biofilms, achieved by light assisted antibiotic and by the antibiotic monotherapy at 10-fold higher concentration, were equivalent. The present achievement could motivate the development of light assisted antibiotic treatments for treating infections.

The talk reviews how visible and UV solid state lighting in the future may be used in biomedical applications such as cancer therapy, disinfection of specific bacteria, and improved health by using light-induced enhancement of vitamin D.