Far-UVC light safely kills ( or inactivate ) airborne coronaviruses
The researchers found that more than 99.9% of the exposed virus had been killed by a very low exposure to far-UVC light.
Based on their results, the researchers estimate that continuous exposure to far-UVC light at the current regulatory limit would kill 90% of airborne viruses in about 8 minutes, 95% in about 11 minutes, 99% in about 16 minutes, and 99.9% in about 25 minutes.
Manuela Buonanno, David Welch, Igor Shuryak, David J. Brenner. Far-UVC light (222 nm) efficiently and safely inactivates airborne human coronaviruses. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-67211-2
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The hippocampus lost about 30 percent of capacity in low light in just 4 weeks as well as a steep decline in brain derived neurotrophic factor (Animal Model)
* Grass rats were housed in either a 12: 12 h bright light–dark (brLD, 1,000 lux) or dim light-dark (dimLD, 50 lux) cycle.
Light modulates hippocampal function and spatial learning in a diurnal rodent species: A study using male nile grass rat (Arvicanthis niloticus)DOI: 10.1002/hipo.22822
- Spanish research has shown that blue LED light can irreparably damage the cells in the eye’s retina
- This is not the first time energy-saving bulbs have been criticised – fluorescent bulbs emit dangerous UV light
PUBLISHED: 08:13 EST, 14 May 2013 | UPDATED: 16:01 EST, 14 May 2013
Eco-friendly LED lights may damage your eyes, according to new research.
A study has discovered that exposure to LED lights can cause irreparable harm to the retina of the human eye.
LED lights have been touted as a super-efficient alternative to traditional bulbs because they use up to 85 per cent less energy and each bulb can last up to 10 years.
In April, Philips, the world’s biggest lighting maker, reported a 38 per cent jump in LED light sales from last year.
A Spanish study has shown that the light emitted by LED bulbs can damage the cells in the retina. Some experts are now calling for a filter to be fitted in the bulbs (file picture)
They are already widely used in mobile phones, televisions, computer screens and can also be fitted as a replacement for traditional lighting in the home.
LEDs are much more expensive that traditional bulbs – costing around £25 for an equivalent 100w compared to around £1 for an incandescent bulb – although manufacturers claim that consumers make their money back because the use such little energy.
The government announced it was phasing out incandescent bulbs in 2007 after an EU directive banned their use. The 100w bulb was the first to go in 2009 and lower wattage bulbs continue to be phased out gradually.
The ban caused public outrage as customers were forced to spend large sums of money on lighting that not only gave an unpleasantly ‘cold’ light but also caused some people to report symptoms of itchy skin and headaches.
The government’s Enhanced Capital Allowance Scheme, which was brought in to help cut UK carbon emissions, is also pushing the use of LED lighting by offering businesses added tax relief if they use LED and other low-energy bulbs.
Dr. Celia Sánchez-Ramos, of Complutense University in Madrid and who led the study, explained that light from LEDs, or light-emitting diodes, comes from the short-wave, high-energy blue and violet end of the visible light spectrum.
Incandescent bulbs (left) are being phased out in favour of low-energy alternatives such as CFLs (right), but there are concerns about the safety of the new generation of so-called ‘environmentally friendly’ lighting
She said that prolonged, continuous exposure to this light may be enough to damage a person’s retina.
The retina is composed of light-sensitive tissue that is responsible for detecting light and in turn allowing us to see.
‘This problem is going to get worse, because humans are living longer and children are using electronic devices from a young age, particularly for schoolwork,’ Sánchez-Ramos told ThinkSpain.com.
Enterprising: Lighting shop owner Kerry Nicholau, from Twickenham, stockpiled 3000 incandescent bulbs after 75 watt bulbs were phased out in 2011
‘Eyes are not designed to look directly at light — they are designed to see with light,’ Sánchez-Ramos said.
Her comments are partly based on her 2012 study that was published in the journal Photochemistry and Photobiology.
The study found that LED radiation caused significant damage to human retinal pigment epithelial cells in vitro.
Sánchez-Ramos added that modern humans have their eyes open for roughly 6,000 hours a year, and are exposed to artificial light for the majority of that time.
Some experts have called for the LED lights to have built-in filters to cut out the blue glare.
This is not the first time energy-saving lights have come under scrutiny for safety reasons. Compact fluorescent light bulbs, or CFLs, have been criticized for the high levels of mercury they contain as well as the UV radiation they can emit.
LED lights have also been blamed for the changing hues of masterpieces in art galleries.
A study carried out by the University of Antwerp earlier this year found that LED lights were bleaching the paint on works by Van Gogh and Cézanne.
Miniature laser operates at room temperature and defies the diffraction limit of light
A Northwestern University research team has found a way to manufacture single laser devices that are the size of a virus particle and that operate at room temperature. These plasmonic nanolasers could be readily integrated into silicon-based photonic devices, all-optical circuits and nanoscale biosensors.
Reducing the size of photonic and electronic elements is critical for ultra-fast data processing and ultra-dense information storage. The miniaturization of a key, workhorse instrument — the laser — is no exception.
The results are published in the journal Nano Letters.
“Coherent light sources at the nanometer scale are important not only for exploring phenomena in small dimensions but also for realizing optical devices with sizes that can beat the diffraction limit of light,” said Teri Odom, a nanotechnology expert who led the research.
Odom is the Board of Lady Managers of the Columbian Exposition Professor of Chemistry in the Weinberg College of Arts and Sciences and a professor of materials science and engineering in the McCormick School of Engineering and Applied Science.
“The reason we can fabricate nano-lasers with sizes smaller than that allowed by diffraction is because we made the lasing cavity out of metal nanoparticle dimers — structures with a 3-D ‘bowtie’ shape,” Odom said.
These metal nanostructures support localized surface plasmons — collective oscillations of electrons — that have no fundamental size limits when it comes to confining light.
The use of the bowtie geometry has two significant benefits over previous work on plasmon lasers: (1) the bowtie structure provides a well-defined, electromagnetic hot spot in a nano-sized volume because of an antenna effect, and (2) the individual structure has only minimal metal “losses” because of its discrete geometry.
“Surprisingly, we also found that when arranged in an array, the 3-D bowtie resonators could emit light at specific angles according to the lattice parameters,” Odom said.
The Nano Letters paper, titled “Plasmonic Bowtie Nanolaser Arrays,” is available at http://dx.doi.org/10.1021/nl303086r.
|IMAGE:Alpesh Patel, a rising MCG School of Dentistry junior, studies the effects of a blue curing light on tumors.|
A blue curing light used to harden dental fillings also may stunt tumor growth, Medical College of Georgia researchers say.
“The light sends wavelengths of blue-violet light to the composite, which triggers hardening,” says Alpesh Patel, a rising MCG School of Dentistry junior. “The light waves produce free radicals that activate the catalyst and speed up polymerization of the composite resin. In oral cancer cells, though, those radicals cause damage that decreases cell growth and increases cell death.”
Mr. Patel, who has been working with Dr. Jill Lewis, associate professor of oral biology, Dr. Regina Messer, associate professor of oral rehabilitation and oral biology, and Dr. John Wataha, adjunct professor of oral rehabilitation and oral biology, studied 10 tumor-bearing mice, five treated with the light and five untreated.
He exposed half the mice to the blue light for 90 seconds a day for 12 days. Then the tumors were extracted and each one was split into two sections. Half were used to create slides for tissue analysis, and half were frozen to prepare protein extracts.
Tissue analysis indicated an approximate 10 percent increase in cell suicide, or apoptosis, in the light-treated tumors. The frozen protein extracts revealed a nearly 80 percent decrease in cell growth in the light-treated tumors.
“The decrease in cell growth, combined with increased apoptosis, helps explain why the tumors didn’t grow as much because you have cells that aren’t dividing and you have cells that are committing suicide,” Mr. Patel says.
Dr. Lewis predicts treating the tumors with blue light sooner will increase the rate of apoptosis, possibly preventing the tumor from ever becoming measurable and easing treatment.
“One desirable feature we’ve observed with the blue light is that non-cancerous cells appear unaffected at light doses that kill tumor cells,” says Dr. Lewis. “We’re thinking that some day, blue light therapy may serve as an adjunct to conventional cancer therapy. Patients may, therefore, receive lower doses of chemotherapy, which would decrease the adverse effects most cancer patients experience from standard chemotherapy regimens.”
Mr. Patel presented his findings at the 2008 American Association for Dental Research Student Research Group DENTSPLY/Caulk competition, winning third place in the basic science category. He and rising junior MCG School of Dentistry student Beth Rainwater were two of only seven students nationwide to be selected for the competition