Implementation and characterisation of a sterilisation module consisting of novel 265 nm UVC LED packages

To efficiently fight against the COVID-19 pandemic, a sterilisation module using 265 nm UVC LED packages was developed. In this paper, the performance of the sterilisation module in terms of irradiance uniformity, junction temperature increase and sterilisation efficiency were characterised. The irradiance uniformity fluctuation across the four corners and the centre point in a 130 mm × 130 mm area was below 10%, exhibiting good uniformity. Uniform irradiance was important to achieve consistent sterilisation, which was the primary difference between the UVC LED package developed and commercial UVC LED packages. Key to achieving uniform irradiance was the structure, consisting of a stacked silicon reflector and a secondary optical lens designed by ray tracing simulation. The junction temperature increase of the 265 nm UVC LED package driving at 200 mA was only 28°C, sufficiently low to exhibit better reliability and performance. A 99.99% sterilisation efficiency on E. coli bacteria was achieved within one minute with UV dosage of 2.7 mJ/cm2 at 200 mA driving current. From the results, the novel 265 nm UVC LED package was a time-efficient solution for disinfection purposes. © 2021 The Hong Kong Institution of Engineers.

Racial/Ethnic Differences in Social Health of Older Adults in a Northern California Healthcare System

Background: The COVID-19 pandemic heightened concerns about the social health of older adults and potential exacerbation of racial disparities in health, well-being, and healthcare access. Methods: We used weighted data for 4282 Kaiser Permanente Northern California (KPNC) members aged 65-85 who responded to the 2020 KPNC Member Health Survey to estimate prevalence of frequent loneliness, lack of social support, financial strains, and other stressors during the prior 12 months. Results: Overall, 5% often felt lonely or socially isolated, and 37% often did not get sufficient social/emotional support (Figure). While approximately 4% had problems “making ends meet”, 10% worried about financial security. Cost led to 2-3% being food insecure, eating less healthy foods, and delaying/foregoing medical care, and 11% delaying/foregoing dental care. Black adults were most likely to report these financial strains, as well as experience harassment/ discrimination and worry about neighborhood violence. Asian/Pacific Islander adults (API) were most likely (57%) and White adults least likely (32%) to report lack of social/emotional support. Conclusions: While many older adults experienced adverse financial and social circumstances during the pandemic, Black adults were more likely than White adults to indicate financial and healthcare access strains. More research is needed on effective screening for financial and other social risks in diverse older adult populations to deliver socially and culturally appropriate care to vulnerable populations.