Assessing Human Eye Exposure to UV Light: A Narrative Review.

Exposure to ultraviolet light is associated with several ocular pathologies. Understanding exposure levels and factors is therefore important from a medical and prevention perspective. A review of the current literature on ocular exposure to ultraviolet light is conducted in this study. It has been shown that ambient irradiance is not a good indicator of effective exposure and current tools for estimating dermal exposure have limitations for the ocular region. To address this, three methods have been developed: the use of anthropomorphic manikins, measurements through wearable sensors and numerical simulations. The specific objective, limitations, and results obtained for the three different methods are discussed

Sun exposure to the eyes: predicted UV protection effectiveness of various sunglasses.

The aim of this study was to assess solar ultraviolet radiation (UVR) doses received by the eyes in different exposure situations, and to predict the sun protection effectiveness provided by various styles of sunglasses at facial, periorbital, and ocular skin zones including the cornea and accounting for different head positions. A 3D numeric model was optimized to predict direct, diffuse and reflected erythemally weighted UVR doses received at various skin zones. Precisely defined facial, periorbital, and ocular skin zones, sunglasses (goggles, medium-, and large-sized sunglasses) and three head positions were modeled to simulate daily (08:00-17:00) and midday (12:00-14:00) UVR doses. The shading from sunglasses' frame and lenses' UVR transmission were used to calculate a predictive protection factor (PPF [%]). Highest ocular daily UVR doses were estimated at the uncovered cornea (1718.4 J/m <sup>2</sup> ). Least sun protection was provided by middle-sized sunglasses with highest midday dose at the white lateral (290.8 J/m <sup>2</sup> ) and lateral periorbital zones (390.9 J/m <sup>2</sup> ). Goggles reached almost 100% protection at all skin zones. Large-sized sunglasses were highly effective in winter; however, their effectiveness depended on diffuse UVR doses received. In "looking-up" head positions highest midday UVR doses were received at the unprotected cornea (908.1 J/m <sup>2</sup> ), totally protected when large-sized sunglasses are used. All tested sunglass lenses fully blocked UVR. Sunglasses' protection effectiveness is strongly influenced by geometry, wearing position, head positions, and exposure conditions. Sunglasses do not totally block UVR and should be combined with additional protection means. 3D modeling allows estimating UVR exposure of highly sensitive small skin zones, chronically exposed and rarely assessed

Reusability of filtering facepiece respirators after decontamination through drying and germicidal UV irradiation.

During pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effectiveness of decontamination as well as the performance of the reused respirators. Disposable respirators were subjected to ultraviolet germicidal irradiation (UVGI) treatment at single or successive doses of 60 mJ/cm <sup>2</sup> after a short drying cycle (30 min, 70°C). The germicidal efficacy of this treatment was tested by spiking respirators with two staphylococcal bacteriophages (vB_HSa_2002 and P66 phages). The respirator performance was investigated by the following parameters: particle penetration (NaCl aerosol, 10-300 nm), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry and mechanical tensile tests. No viable phage particles were recovered from any of the respirators after decontamination (log reduction in virus titre >3), and no reduction in chemical or physical properties (SEM, particle penetrations <5%-6%) were observed. Increasing the UVGI dose 10-fold led to chemical alterations of the respirator filtration media (FTIR) but did not affect the physical properties (particle penetration), which was unaltered even at 3000 mJ/cm <sup>2</sup> (50 cycles). When respirators had been used by healthcare workers and undergone decontamination, they had particle penetration significantly greater than never donned respirators. This decontamination procedure is an attractive method for respirators in case of shortages during a SARS pandemic. A successful implementation requires a careful design and particle penetration performance control tests over the successive reuse cycles

Determining thresholds for spatial urban design and transport features that support walking to create healthy and sustainable cities:findings from the IPEN Adult study

An essential characteristic of a healthy and sustainable city is a physically active population. Effective policies for healthy and sustainable cities require evidence-informed quantitative targets. We aimed to identify the minimum thresholds for urban design and transport features associated with two physical activity criteria: at least 80% probability of engaging in any walking for transport and WHO's target of at least 15% relative reduction in insufficient physical activity through walking. The International Physical Activity and the Environment Network Adult (known as IPEN) study (N=11 615; 14 cities across ten countries) provided data on local urban design and transport features linked to walking. Associations of these features with the probability of engaging in any walking for transport and sufficient physical activity (≥150 min/week) by walking were estimated, and thresholds associated with the physical activity criteria were determined. Curvilinear associations of population, street intersection, and public transport densities with walking were found. Neighbourhoods exceeding around 5700 people per km(2), 100 intersections per km(2), and 25 public transport stops per km(2) were associated with meeting one or both physical activity criteria. Shorter distances to the nearest park were associated with more physical activity. We use the results to suggest specific target values for each feature as benchmarks for progression towards creating healthy and sustainable cities

The role of water fittings in intensive care rooms as reservoirs for the colonization of patients with Pseudomonas aeruginosa

International audienceOBJECTIVE: To assess the role of the water environment in the Pseudomonas aeruginosa colonization of patients in intensive care units in the absence of a recognized outbreak. DESIGN AND SETTING: Prospective, single-centre study over an 8-week period in two adult ICUs at a university hospital. Environmental samples were taken from the water fittings of rooms once per week, during a 8-week period. Patients were screened weekly for P. aeruginosa carriage. Environmental and humans isolates were genotyped by using pulsed-field gel electrophoresis. RESULTS: P. aeruginosa was detected in 193 (86.2%) of the 224 U-bend samples and 10 of the 224 samples taken from the tap (4.5%). Seventeen of the 123 patients admitted were colonized with P. aeruginosa. Only one of the 14 patients we were able to evaluate was colonized by a clone present in the water environment of his room before the patient's first positive sample was obtained. CONCLUSION: The role of the water environment in the acquisition of P. aeruginosa by intensive care patients remains unclear, but water fittings seem to play a smaller role in non-epidemic situations than expected by many operational hospital hygiene teams

Allele Intersection Analysis: A Novel Tool for Multi Locus Sequence Assignment in Multiply Infected Hosts

Wolbachia are wide-spread, endogenous α-Proteobacteria of arthropods and filarial nematodes. 15–75% of all insect species are infected with these endosymbionts that alter their host's reproduction to facilitate their spread. In recent years, many insect species infected with multiple Wolbachia strains have been identified. As the endosymbionts are not cultivable outside living cells, strain typing relies on molecular methods. A Multi Locus Sequence Typing (MLST) system was established for standardizing Wolbachia strain identification. However, MLST requires hosts to harbour individual and not multiple strains of supergroups without recombination. This study revisits the applicability of the current MLST protocols and introduces Allele Intersection Analysis (AIA) as a novel approach. AIA utilizes natural variations in infection patterns and allows correct strain assignment of MLST alleles in multiply infected host species without the need of artificial strain segregation. AIA identifies pairs of multiply infected individuals that share Wolbachia and differ in only one strain. In such pairs, the shared MLST sequences can be used to assign alleles to distinct strains. Furthermore, AIA is a powerful tool to detect recombination events. The underlying principle of AIA may easily be adopted for MLST approaches in other uncultivable bacterial genera that occur as multiple strain infections and the concept may find application in metagenomic high-throughput parallel sequencing projects

Tetradecylthioacetic Acid Increases Hepatic Mitochondrial β-Oxidation and Alters Fatty Acid Composition in a Mouse Model of Chronic Inflammation

The administration of tetradecylthioacetic acid (TTA), a hypolipidemic and anti-inflammatory modified bioactive fatty acid, has in several experiments based on high fat diets been shown to improve lipid transport and utilization. It was suggested that increased mitochondrial and peroxisomal fatty acid oxidation in the liver of Wistar rats results in reduced plasma triacylglycerol (TAG) levels. Here we assessed the potential of TTA to prevent tumor necrosis factor (TNF) α-induced lipid modifications in human TNFα (hTNFα) transgenic mice. These mice are characterized by reduced β-oxidation and changed fatty acid composition in the liver. The effect of dietary treatment with TTA on persistent, low-grade hTNFα overexpression in mice showed a beneficial effect through decreasing TAG plasma concentrations and positively affecting saturated and monounsaturated fatty acid proportions in the liver, leading to an increased anti-inflammatory fatty acid index in this group. We also observed an increase of mitochondrial β-oxidation in the livers of TTA treated mice. Concomitantly, there were enhanced plasma levels of carnitine, acetyl carnitine, propionyl carnitine, and octanoyl carnitine, no changed levels in trimethyllysine and palmitoyl carnitine, and a decreased level of the precursor for carnitine, called γ-butyrobetaine. Nevertheless, TTA administration led to increased hepatic TAG levels that warrant further investigations to ascertain that TTA may be a promising candidate for use in the amelioration of inflammatory disorders characterized by changed lipid metabolism due to raised TNFα levels

Novel approach to analysing large data sets of personal sun exposure measurements

Personal sun exposure measurements provide important information to guide the development of sun awareness and disease prevention campaigns. We assess the scaling properties of personal ultraviolet radiation (pUVR) sun exposure measurements using the wavelet transform (WT) spectral analysis to process long-range, high-frequency personal recordings collected by electronic UVR dosimeters designed to measure erythemal UVR exposure. We analysed the sun exposure recordings of school children, farmers, marathon runners and outdoor workers in South Africa, and construction workers and work site supervisors in New Zealand. We found scaling behaviour in all the analysed pUVR data sets. We found that the observed scaling changes from uncorrelated to long-range correlated with increasing duration of sun exposure. Peaks in the WT spectra that we found suggest the existence of characteristic times in sun exposure behaviour that were to some extent universal across our data set. Our study also showed that WT measures enable group classification, as well as distinction between individual UVR exposures, otherwise unattainable by conventional statistical methods

Inequitable walking conditions among older people: examining the interrelationship of neighbourhood socio-economic status and urban form using a comparative case study

<p>Abstract</p> <p>Background</p> <p>Supportive neighbourhood walking conditions are particularly important for older people as they age and who, as a group, prefer walking as a form of physical activity. Urban form and socio-economic status (SES) can influence neighbourhood walking behaviour. The objectives of this study were: a) to examine how urban form and neighbourhood SES inter-relate to affect the experiences of older people who walk in their neighbourhoods; b) to examine differences among neighbourhood stakeholder key informant perspectives on socio-political processes that shape the walkability of neighbourhood environments.</p> <p>Methods</p> <p>An embedded comparative case study examined differences among four Ottawa neighbourhoods that were purposefully selected to provide contrasts on urban form (inner-urban versus suburban) and SES (higher versus lower). Qualitative data collected from 75 older walkers and 19 neighbourhood key informants, as well as quantitative indicators were compared on the two axes of urban form and SES among the four neighbourhoods.</p> <p>Results and discussion</p> <p>Examining the inter-relationship of neighbourhood SES and urban form characteristics on older people's walking experiences indicated that urban form differences were accentuated positively in higher SES neighbourhoods and negatively in lower SES neighbourhoods. Older people in lower SES neighbourhoods were more affected by traffic hazards and more reliant on public transit compared to their higher SES counterparts. In higher SES neighbourhoods the disadvantages of traffic in the inner-urban neighbourhood and lack of commercial destinations in the suburban neighbourhood were partially offset by other factors including neighbourhood aesthetics. Key informant descriptions of the socio-political process highlighted how lower SES neighbourhoods may face greater challenges in creating walkable places. These differences pertained to the size of neighbourhood associations, relationships with political representatives, accessing information and salient neighbourhood association issues. Findings provide evidence of inequitable walking environments.</p> <p>Conclusion</p> <p>Future research on walking must consider urban form-SES inter-relationships and further examine the equitable distribution of walking conditions as well as the socio-political processes driving these conditions. There is a need for municipal governments to monitor differences in walking conditions among higher and lower SES neighbourhoods, to be receptive to the needs of lower SES neighbourhood and to ensure that policy decisions are taken to address inequitable walking conditions.</p

Insights into household transmission of SARS-CoV-2 from a population-based serological survey

Understanding the risk of infection from household- and community-exposures and the transmissibility of asymptomatic infections is critical to SARS-CoV-2 control. Limited previous evidence is based primarily on virologic testing, which disproportionately misses mild and asymptomatic infections. Serologic measures are more likely to capture all previously infected individuals. We apply household transmission models to data from a cross-sectional, household-based population serosurvey of 4,534 people ≥5 years from 2,267 households enrolled April-June 2020 in Geneva, Switzerland. We found that the risk of infection from exposure to a single infected household member aged ≥5 years (17.3%,13.7-21.7) was more than three-times that of extra-household exposures over the first pandemic wave (5.1%,4.5-5.8). Young children had a lower risk of infection from household members. Working-age adults had the highest extra-household infection risk. Seropositive asymptomatic household members had 69.4% lower odds (95%CrI,31.8-88.8%) of infecting another household member compared to those reporting symptoms, accounting for 14.5% (95%CrI, 7.2-22.7%) of all household infections