Killer immunoglobulin-like Receptors (KIR) haplogroups A and B track with Natural Killer Cells and Cytokine Profile in Aged Subjects: Observations from Octo/Nonagenarians in the Belfast Elderly Longitudinal Free-living Aging STudy (BELFAST)

BACKGROUND: Natural Killer Cells (NK) play an important role in detection and elimination of virus-infected, damaged or cancer cells. NK cell function is guided by expression of Killer Immunoglobulin-like Receptors (KIRs) and contributed to by the cytokine milieu. KIR molecules are grouped on NK cells into stimulatory and inhibitory KIR haplotypes A and B, through which NKs sense and tolerate HLA self-antigens or up-regulate the NK-cytotoxic response to cells with altered HLA self-antigens, damaged by viruses or tumours. We have previously described increased numbers of NK and NK-related subsets in association with sIL-2R cytokine serum levels in BELFAST octo/nonagenarians. We hypothesised that changes in KIR A and B haplotype gene frequencies could explain the increased cytokine profiles and NK compartments previously described in Belfast Elderly Longitudinal Free-living Aging STudy (BELFAST) octo/nonagenarians, who show evidence of ageing well. RESULTS: In the BELFAST study, 24% of octo/nonagenarians carried the KIR A haplotype and 76% KIR B haplotype with no differences for KIR A haplogroup frequency between male or female subjects (23% v 24%; p=0.88) or for KIR B haplogroup (77% v 76%; p=0.99). Octo/nonagenarian KIR A haplotype carriers showed increased NK numbers and percentage compared to Group B KIR subjects (p=0.003; p=0.016 respectively). There were no KIR A/ B haplogroup-associated changes for related CD57+CD8 ((high or low)) subsets. Using logistic regression, KIR B carriers were predicted to have higher IL-12 cytokine levels compared to KIR A carriers by about 3% (OR 1.03, confidence limits CI 0.99–1.09; p=0.027) and 14% higher levels for TGF-β (active), a cytokine with an anti-inflammatory role, (OR 1.14, confidence limits CI 0.99–1.09; p=0.002). CONCLUSION: In this observational study, BELFAST octo/nonagenarians carrying KIR A haplotype showed higher NK cell numbers and percentage compared to KIR B carriers. Conversely, KIR B haplotype carriers, with genes encoding for activating KIRs, showed a tendency for higher serum pro-inflammatory cytokines compared to KIR A carriers. While the findings in this study should be considered exploratory they may serve to stimulate debate about the immune signatures of those who appear to age slowly and who represent a model for good quality survivor-hood

Feasibility of ceiling-based luminance distribution measurements

There is a high relevancy in the luminance distribution related to the perceived visual comfort. Moreover, the required technology is maturing such that it is feasible to integrate such devices in lighting control systems, which is expected to improve the overall lighting quality in office environments, or to conduct long-term field studies. Preferably, the luminance distribution measurement corresponds to the visual field of the user. However, for long-term measurements this is not feasible as this causes interference. Therefore, this study aimed to find a suitable ceiling-based position for luminance distribution measurements. In a first phase, the most suitable ceiling-based measurement position was identified for four luminance based metrics: Desktop Luminance, Monitor Luminance, B40 Luminance, and Retinal Illuminance. The results showed that a ceiling-based position above the aisle with a 20° angle relative to the ceiling was the most suitable position because its field of view has large similarities with the field and angle of view of the user. In a second phase, the performance of this most suitable position found in phase 1 was assessed under real office conditions, and compared with the visual field of the user. The Desktop and Monitor Luminance achieved an acceptable accuracy with very basic commissioning. The Retinal illuminance was measured with a reasonable accuracy when an elaborate calibration procedure was applied. For the B40 Luminance, in all scenarios, inaccuracies above 20% were found. This study shows that ceiling-based measurements are feasible, except for the B40 luminance, however, one should account for the introduced uncertainty

Recommendations for long-term luminance distribution measurements: the spatial resolution

Currently, luminance distribution measurement devices are increasingly used because there is high relevancy in the luminance distribution to the perceived visual comfort, also technology is maturing. It is now feasible to conduct long-term measurements and integrate these devices into lighting control systems. This, however, can result in new issues such as privacy controversies and high computational costs, induced by high spatial resolutions. Therefore, this study aims to propose a spatial resolution that is able to measure the luminance accurately while minimizing privacy sensitivity and computational costs. This is done based on luminance distribution measurements in office environments. The accuracy of lower resolution luminance distributions is tested for the mean and maximum luminance and the illuminance. Additionally, the ability to recognize faces is measured as an indicator for privacy-sensitive content. Finally, the processing time is measured as an indicator for the computational costs. The results show that for mean luminance or illuminance measurements the spatial resolution can be reduced significantly to 440 x 330 and 720 x 540 pixels, respectively. This spatial resolution does not compromise the accuracy while minimizing the ability of automated facial recognition and reducing the computational costs significantly. However, for maximum luminance measurements, a high resolution of 3000 x 2250 pixels is deemed appropriate, although this does allow automated facial recognition and results in high computation costs. A toolbox has been developed to assist others in choosing a relevant spatial resolution for their luminance camera during long term luminance measurements in typical office environments

A multidirectional spectral measurement method and instrument to investigate non-image-forming effects of light

Light directionality, spectrum, and relevant radiometric or photometric quantity are believed essential factors influencing the magnitude of non-image-forming effects. In this paper, a measurement method and an instrument (the multidirectional spectroradiometer - MuS) is proposed, which considers different light incidents and spectra simultaneously, therefore, enables measurement of light characteristics relevant for non-image-forming effects. The MuS consists of four spectroradiometers measuring in different directions. Four spectrometers using optical fibers were configured to measure the spectral irradiance within a wavelength range from 200 to 1100 nm with ~5.7 nm pixel resolution. Application of the MuS facilitates a better understanding of the non-image-forming light characteristics of spaces. The MuS is tested with stable electric lighting and with dynamic daylight conditions and is proven reliable to perform continuous spectral measurements in different directions simultaneously. Results show a substantial difference in measured radiation magnitude and spectral distribution in different directions, which suggests varying impact on non-image-forming effects

Light for patient safety: impact of light on reading errors of medication labels

Background: In in-patient care facilities, 1 in 5 medication doses is administered incorrectly. A hospital environment which supports the performance of the health-care staff will positively impact patient safety. Objectives: Determine which lighting leads to the least reading mistakes of medication labels. Design: Experimental study with repeated measures. Setting: Study was performed under controlled conditions in the Netherlands. Participants: In total the data of 37 participants are analyzed and described. Inclusion criteria were: female, aged between either 18–30 years old (M = 26.0, SD = 3.1) or between 55 and 67 years old (M = 57.9, SD = 2.7) years old, with normal vision. Eligible participants were personally invited to participate. Methods: Per participant, the readability of three different labels (Blister, Baxter and Orange) and four different font sizes (4.5 pt, 3.5 pt, 3.0 pt, and 2.5 pt Arial Capital) were assessed under nine different light conditions (three illuminances (E),100lx, 500lx, and 1000lx and three correlated color temperatures (T cp ): 3000 K, 4000 K, and 6500 K). The participants had to read out loud text sequences of 10 letters per medication label. The numbers of errors were counted and analyzed. Results: The results show a significant difference between numbers of errors related to: 1. Light condition, 2. Age, 3. Label material, 4. Font size. The impact of the light condition is not identical for the different types of label and the font sizes. The impact of the light conditions is the strongest for the smallest font size (2.5 pt) and participants with Visual Acuity < 1. Conclusion: Lighting has an impact on the number of errors. Older people make more errors than younger people. The type of label has an impact on the number of errors made. The font size has an impact on number of errors made. For font sizes <4.5 pt (Arial), reading medication labels (Blister, Baxter and Orange) under illuminance levels of 100lx, will lead to significantly more errors than E ≥ 500lx. The light condition that generates the least errors for the total test population, all font sizes, and all different materials was the one with an E of 1000lx and a T cp of 4000 K. People with an insufficient Visual Acuity (VA) benefit most from a higher illuminance level, especially for the Orange labels. When the VA is well-adjusted (sufficient to good) and the font size is as recommended for medication labels (Arial Capital ≥ 4.5 pt) the impact of the lighting on number of errors is limited for all of the age groups