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The discriminatory power of the UVB variable is somewhat limited in this study, because UVB radiation is low at this time of the year, particularly at the high northern latitude of UK—larger effects might be observed if variation in UVB is greater. We only used ambient UVB, and did not capture individual behavioural differences that would determine the actual level of vitamin D synthesis in the skin, such as duration and time of day spent outside, clothing, etc. It is important to note that time of year is the strongest predictor of vitD-UVB. To avoid bias control dates were assigned to follow the same distribution as case dates, which might have led to artificially diminished differences in vitD-UVB between cases and controls, however analysis relating to hospitalisation and death are not affected by this. We also conducted an analysis of the genetically-predicted vitamin D and a number of state-of-the-art MR analyses. However, the main limitation is the lack of power. Given the small number of COVID-19 patients and the relatively small percentage of variance (4.2%) explained by vitamin D-related genetic variants, this MR study was not adequately powered to detect small causal effect and negative results should be interpreted with caution. Additionally, MR studies only consider linear effects between 25-OHD levels and COVID-19 risk, which do not capture what happens at the extremes of vitamin D deficiency. Therefore, it cannot rule out the possibility that seriously ill patients (due to an underlying pathology) with extremely low vitamin D levels could be predisposed to COVID-19 infection and increased COVID-19 severity and mortality. Furthermore, 25-OHD levels are the used biomarker of vitamin D status in the study population, nevertheless, they correlate poorly with the active form of vitamin D (1,25-OH2D), which exerts the effects of vitamin D on a cellular level. Thus, this study cannot exclude effects of 1,25-OH2D on COVID-19 risk.

Another limitation of this cohort relates to the fact that not all participants have been tested for present (or past) COVID-19 infection; consequentially, taking participants who were not tested as controls could be a potential source of bias, given that misclassification of controls might be substantial due to the presence of asymptomatic infected individuals, further driving our findings to the null. This is evident from the 1:2 ratio between outpatient vs. inpatient cases. It should be acknowledged that the COVID-19 cases in UK biobank have a high rate of hospitalisation due to the very limited and targeted testing at this stage of the pandemic in the UK, so this study reflects mainly those with more severe COVID-19 and gives less information about true infection risk, or risk of milder disease. In addition, we excluded individuals with a negative COVID-19 testing result from the controls due to the risk of those being false negatives. Although there is a risk of introducing selection bias, we believe that the risk of introducing misclassification bias if we included them in the analysis could be higher22,23. Additionally, given the presence of asymptomatic infected individuals, taking participants who were not tested as controls could also be another potential source of bias. Our study assessed the effect of genetically predicted vitamin D levels on COVID-19 risk while taking into consideration of ambient UVB radiation during the pandemic. We show an indication of an inverse association between genetically predicted vitamin D levels and severe COVID-19. Findings from our study are consistent with a recent randomised controlled trial (RCT) that found protective effect of vitamin D supplementation among those hospitalised with COVID-1924. However, other clinical trials did not show an effect. For instance, a randomised trial of 240 patients showed that supplementation with a single very large dose of 200,000 IU of vitamin D3 that increased serum vitamin D levels (21–44 ng/ml) was nonetheless ineffective in decreasing the length of hospital stay or any other clinical outcomes among hospitalized patients with severe COVID-1925. It has been estimated that one SD change in standardized natural-log transformed 25-OHD levels corresponds to a change in 25-OHD levels of 29.2 nmol/l in vitamin D insufficient individuals (serum 25-OHD levels 50 nmol/l), which is comparable to the 21.2 nmol/l mean increase in 25-OHD levels conferred by taking daily 400 IU of cholecalciferol, the amount of vitamin D most often found in vitamin D supplements26. This estimation has clinical implication on the dose of vitamin D supplement for disease prevention. Given the lack of highly effective therapies against COVID-19, it is important to remain open-minded to emerging results from rigorously conducted studies of vitamin D.

In conclusion, we found no significant associations between COVID-19 risk and measured 25-OHD levels after adjusted for covariates, but this finding is limited by the fact that the vitamin D levels were measured on average 11 years before the pandemic. Ambient UVB was strongly and inversely associated with COVID-19 hospitalization and death. The main MR analysis did not show that genetically-predicted vitamin D levels were causally associated with COVID-19 risk, although MR sensitivity analyses indicated a potential causal effect. Overall, the effect of vitamin D levels on the risk or severity of COVID-19 remains controversial, further studies are needed to validate vitamin D supplementation as a means of protecting against worsened COVID-19.

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Since the spread of virus causing COVID-19 continues, experts recommended wearing homemade facemasks when surgical or N95 masks are not available to prevent the spread of the pandemic. While such makeshift masks are more economical and accessible in low-capita countries, the effectiveness of cloth masks has not been studied in depth.

In Physics of Fluids, researchers from the Indian Institute of Science studied the fate of a large-sized surrogate cough droplets at different velocities, corresponding from mild to severe, while using various locally procured fabrics as masks.

“Our results show cotton, towel-based fabrics were most effective among the considered fabrics and must be stitched together as multiple layers for making homemade facemasks,” said author Saptarshi Basu. “A three or more-layered homemade mask is recommended, since it can suppress aerosolization significantly.”

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A Science Immunology analysis of patient samples collected before the #COVID19 pandemic shows that killer #Tcells that can recognize #SARSCoV2, despite never having encountered the virus before, are located in tissues, rather than circulating in blood.

Tissue-resident memory CD8+ T cells in unexposed oropharyngeal lymphoid tissue exhibit specificity for SARS-CoV-2.

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A research team from Nanjing University has used cochlear organoids to identify drugs that can promote the regeneration of hair cells. The study, published in Stem Cell Reports, also identifies a signaling pathway as a potential target for hearing restoration.

Hearing is a complex multistep process that allows us to detect sound and involves three key parts of the ear – the outer, middle and inner ear. Sound waves are collected by the pinna of the outer ear and are funneled into the ear canal until they meet the ear drum (tympanic membrane), causing it to vibrate.

The resulting vibrations are transmitted to the ossicles – comprising a chain of three small bones called malleus, incus and stape – located within the middle ear. Movement of the bones transmits the sound vibrations to the inner ear, sending a signal to the cochlea (a hollow spiraling structure filled with fluid). Vibrations cause the fluid within the cochlea to ripple, forming waves that stimulate the movement of hair cells positioned on the top of the basilar membrane that separates the two fluid-filled chambers running along the cochlea.

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The story illuminates the way that many scientific discoveries become life-changing innovations: with decades of dead ends, rejections and battles over potential profits, but also generosity, curiosity and dogged persistence against scepticism and doubt. “It’s a long series of steps,” says Paul Krieg, a developmental biologist at the University of Arizona in Tucson, who made his own contribution in the mid-1980s, “and you never know what’s going to be useful”.

Hundreds of scientists had worked on mRNA vaccines for decades before the coronavirus pandemic brought a breakthrough.

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Pandemic lockdown forces a new perspective on designs for futuristic AI-based computing devices.

Isaac Newton’s groundbreaking scientific productivity while isolated from the spread of bubonic plague is legendary. University of California San Diego physicists can now claim a stake in the annals of pandemic-driven science.

A team of UC San Diego researchers and colleagues at Purdue University have now simulated the foundation of new types of artificial intelligence computing devices that mimic brain functions, an achievement that resulted from the COVID-19 pandemic lockdown. By combining new supercomputing materials with specialized oxides, the researchers successfully demonstrated the backbone of networks of circuits and devices that mirror the connectivity of neurons and synapses in biologically based neural networks.

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Ending the global sanitation crisis — jack sim, founder world toilet organization.

Around 2 billion people worldwide still lack access to the basic tools of improved sanitation (toilets and latrines). One billion people still have to defecate in the open, and at least 10% of the world’s population is thought to consume food irrigated by raw wastewater. An estimated 800,000 children, younger than 5 years of age, perish from diarrhea each year, including conditions related to cholera, dysentery, hepatitis A, typhoid and polio.

Mr. Jack Sim is the Founder of the World Toilet Organization (https://www.worldtoilet.org/), an organization established with the aim to break the taboo around toilets and this global sanitation crisis.

Mr. Sim is also the founder of the Restroom Association of Singapore, the World Toilet Day initiative, and Bottom of the Pyramid (BOP) Hub.

In 2,001 for “creating good will and bringing the subject into the open” and “mobilizing national support in providing on-the-ground expertise”, Mr. Sim received the Schwab Foundation award for Social Entrepreneur of the Year.

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Reducing naturally occurring errors in protein synthesis (production) improves both health and lifespan, finds a new study in simple model organisms led by researchers at UCL and MRC London Institute of Medical Sciences.

The novel findings, published in Cell Metabolism, are the first to demonstrate a direct link between fewer mistakes and longevity.

Explaining the study, lead author Dr. Ivana Bjedov (UCL Cancer Institute), said: We commonly hear about DNA mutations, which can cause cancer, and are considered one of the underlying causes of ageing.

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