Cancer warning: UV curing

[james_s]

... He said it felt like he had sand in his eyes for several days.

Sounds like the same kind of burn you can get when when working without eye protection near someone who is electric arc welding.  My brother was at a job and got the same burns years back. He wasn't watching the welding work, he was just working nearby.  Lesson learned there.

Yeah arc welding makes a ton of UV light too. I've forgotten to cover various bits of skin a few times while arc welding and got a painful UV burn on a my skin.

[Njk]

Probably the same florescent tubes that were used for germicidal lamps and for erasing EPROMS. Those tubes had quartz envelopes instead of glass so the output contained huge amounts of UV-C, unlike regular glass tubes which blocked most of the UV-C.

Exactly. Medical "germicidal lamp" is a must have device. First, it can erase EPROM (the spectrum peak is just right, 253.7 nm). Second, it can heal a skin wound. Typically, a minor injure is self-healing. But sometimes not, and in that case clean the wound and expose it to UV-C light. For short time, less than a minute. Just use a mask to prevent a healthy skin around the wound from exposure. For me, it always worked excellent.

[thm_w]

"Using three different cell lines—adult human skin keratinocytes, human foreskin fibroblasts, and mouse embryonic fibroblasts—the researchers found that the use of these UV emitting devices for just one 20-minute session led to between 20 and 30 percent cell death, while three consecutive 20-minute exposures caused between 65 and 70 percent of the exposed cells to die."

This is odd because you'd think people would notice the skin death on your fingers if you regularly cure your nails?
But, I do have one of these nail curing lamps for conformal coating, and the max cure time is set as only 2 minutes, so maybe its not noticeable in that time frame.

I've also damaged some skin with a germicidal UV lamp, and its never healed properly, absolutely permanent damage, scary stuff.

warning, sugar can cause diabetes, salt and beer can cause kidney failure, esp beer can cause mental disorder... bla bla bla... who give a rat arse?

Tons of people who care about their health. 

[Njk]

But, I do have one of these nail curing lamps for conformal coating, and the max cure time is set as only 2 minutes, so maybe its not noticeable in that time frame.

Which type of conformal coating you're using? A UV-curable is not the best one, afaik

[thm_w]

But, I do have one of these nail curing lamps for conformal coating, and the max cure time is set as only 2 minutes, so maybe its not noticeable in that time frame.

Which type of conformal coating you're using? A UV-curable is not the best one, afaik

- Humiseal UV50LV UV cure
- MG chem 422C silicone conformal coating, acetone base
- Generic UV cure soldermask

No UV is not the best but there is no strong smell, so much less VOCs, and faster cure.

[Zero999]

Probably the same florescent tubes that were used for germicidal lamps and for erasing EPROMS. Those tubes had quartz envelopes instead of glass so the output contained huge amounts of UV-C, unlike regular glass tubes which blocked most of the UV-C.

Exactly. Medical "germicidal lamp" is a must have device. First, it can erase EPROM (the spectrum peak is just right, 253.7 nm). Second, it can heal a skin wound. Typically, a minor injure is self-healing. But sometimes not, and in that case clean the wound and expose it to UV-C light. For short time, less than a minute. Just use a mask to prevent a healthy skin around the wound from exposure. For me, it always worked excellent.

As mentioned above, UV curing lamps are completely different to germicidal lamps. They emit much longer, lower energy/frequency radiation, typically peaking around 360nm, which is a lot safer.

I've never heard of germicidal lamps being used on wounds. UV will kill bacteria, but also healthy tissue and can cause cancer.

Have there been any medical studies?

I would stick to ordinary antiseptic. It also damages healthy tissue, but at least it's not carcinogenic.

"Using three different cell lines—adult human skin keratinocytes, human foreskin fibroblasts, and mouse embryonic fibroblasts—the researchers found that the use of these UV emitting devices for just one 20-minute session led to between 20 and 30 percent cell death, while three consecutive 20-minute exposures caused between 65 and 70 percent of the exposed cells to die."

This is odd because you'd think people would notice the skin death on your fingers if you regularly cure your nails?

Perhaps it's because the skin cells on the surface are already dead?

I admit, I haven't read the entire study. If they've just tested it on living tissue, it doesn't prove the long wavelengths used to cure nail gel, cause cancer. Did they find out how much of the UV radiation is absorbed by the top layer of dead skin and take that into account? I would suspect a significant amount is absorbed, before it gets to living tissue.

warning, sugar can cause diabetes, salt and beer can cause kidney failure, esp beer can cause mental disorder... bla bla bla... who give a rat arse?

Tons of people who care about their health. 

There is a lot of unfounded panic over health. If you're worried, just wear glasses with a UV filter and sunscreen, when dealing with UV light. Note sunscreen is only been tested to block UVA and UVB, not UVC, and is probably no good to protect against UV from germicidal lamps and arc welding.

[Njk]

I've never heard of germicidal lamps being used on wounds. UV will kill bacteria, but also healthy tissue and can cause cancer.

Have there been any medical studies?

It must be well studied already because it's by no mean something new. I first learned about it a long time ago, in the military aviation. Poor nutrition, vet climate exhaustive duty roster, etc, etc. In that conditions, any accidental wound rarely could heal itself. A magic powders and greases usually were not effective, and the wound was getting bigger and bigger. The medical staff was well aware of that and our doctor did practice the UV therapy as the best method in such cases.

Sure if one can get enough funding, he can study that stuff all over again, as long as he wants, and to publish as many papers as he wants but I'm not interested. Because I know from personal experience that it just work. For me anyway. Of course any method can be abused. An attempt to erase all the germs by single long exposure would be a huge mistake. Use short daily exposure in the course of treatment for several days and all will be fine.

[Njk]

No UV is not the best but there is no strong smell, so much less VOCs, and faster cure.

I'm more used to 2K urethane coatings. Unfortunately, they're no more in fashion.

[thm_w]

As mentioned above, UV curing lamps are completely different to germicidal lamps. They emit much longer, lower energy/frequency radiation, typically peaking around 360nm, which is a lot safer.

I've never heard of germicidal lamps being used on wounds. UV will kill bacteria, but also healthy tissue and can cause cancer.

Have there been any medical studies?

I would stick to ordinary antiseptic. It also damages healthy tissue, but at least it's not carcinogenic.

Yeah would kill some bacteria. Apparently other effects as well, but its not extensively studied in human trials yet that I see:

It has been reported that with appropriate doses, UVC can selectively inactivate microorganisms, while preserving viability of mammalian host cells and, moreover, is reported to promote wound healing. Further, for treatment of wound infections, it is presumed that only limited numbers of repeated UVC irradiation doses would be required, while the UV-induced carcinogenic mutation is a long-term effect of prolonged use of UVC

Exposure of the skin to UV produces erythema, epidermal hyperplasia, increased blood flow in the microcirculation, and also has a bactericidal effect. 26,59 The induced erythema initiates the first phase of healing (inflammatory phase) by creating an inflammatory response via the mechanism of vasodilatation. This may be partially explained by the effects of UV light on the arachidonic acid pathway.60 In addition, UV light exposure induces cellular proliferation in the stratum corneum.61 This proliferation/thickening of the skin is a protective mechanism against further sunlight damage. UV avoidance and use of sunscreens are commonly advised during the re-epithelialization process as well as after wound closure. However, it is possible that the currently accepted practice of UV protection prevents the normal cutaneous response to injury, with melanocyte redistribution and pigmentation creating hypopigmented scars. Previous studies reported that UVC light per se could stimulate wound healing. It was found that UVC light-induced fibronectin release led to increased healing via wound contraction. 62 Fibronectin promotes cell migration and helps regulate cell growth and gene expression. Growth factors are released from epidermal cells exposed to UV irradiation, which further augments the healing cascade.

https://europepmc.org/article/med/7612137
https://www.liebertpub.com/doi/abs/10.1089/wound.2012.0366

Perhaps it's because the skin cells on the surface are already dead?

I admit, I haven't read the entire study. If they've just tested it on living tissue, it doesn't prove the long wavelengths used to cure nail gel, cause cancer. Did they find out how much of the UV radiation is absorbed by the top layer of dead skin and take that into account? I would suspect a significant amount is absorbed, before it gets to living tissue.

You are probably right, the photo is showing petri dishes. So this might be misrepresentation of the actual study.
Its not uncommon if you ask the scientists who performed the study, they will disagree with the news headline.