Archive for the ‘Science’ Category

Good for Use

March 11, 2011

There is an interesting study I just read about today: A glove on your hand can change your mind. In language, “right” is good and “left” is often bad (just look at the French word for “left”, gauche, or the Spanish word for left hand, siniestra, a cognate of sinister). It turns out, that really is related to our handedness. Studies show that left-handers, “left” is good. From the article:

In experiments by psychologist Daniel Casasanto, when people were asked which of two products to buy, which of two job applicants to hire, or which of two alien creatures looks more intelligent, right-handers tended to choose the product, person, or creature they saw on their right, but most left-handers chose the one on their left.

Admittedly, it is a subtle effect, but it is there nonetheless.

But here is the cool part: right-handers’ reactions could be changed by temporarily changing them into lefties. They did so merely by having the right-handers put on a rather awkward ski glove on their right hand for about 12 minutes. At that point the subjects started showing a preference for “left is good.”

How is this related to barefooting? There is no study extending this work to feet, but somehow I just want to think that maybe putting shoes on feet (much more awkward then even a ski glove) can also influence how one perceives good and bad in the world. Maybe that can account for the totally unreasonable reaction that bare feet often seem to elicit.

I guess we ought to call it shoddy thinking.

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Vampire spiders and “human” scent

February 17, 2011

There is a recent study out about how vampire spiders are attracted to human scent. These spiders eat mosquitoes, and in Africa where they live, those mosquitoes often have recently feasted on human blood.

Jumping or Vampire Spider

As noted in this article, “Jumping spiders that love smelly socks could help fight malaria“, the spiders are often found in tall grass adjacent to human dwellings. What the study found was that the spiders spend more time (i.e., are more attracted to) smelly socks, and the conclusion is that they are thereby more attracted to a human odor. You can also see more in this blog post, Vampire spider drawn to the smell of human feet.

So, what is wrong with this picture?????

Who says that smelly socks smell like humans? Smelly socks have their odor because of all the bacteria that live inside shoes, where they thrive on the warm, dark, moist environment there. Real bare feet are not “smelly.” Yes, they probably have a (faint) odor, but it is a real stretch to say that the smell of the bacteria have anything to do with bare feet, or the odor of humans. If anything, the feet of those who regularly go barefoot probably smell more of what they are walking in.

And this study was in Kenya, where many people there really do go barefoot (or at least sandaled) all the time. The whole study is biased by a shod viewpoint. How would these spiders become familiar with the odor of shod feet in Kenya?

Yet, we are assured, in this comment, that “Real sweaty socks (as opposed to synthetic, which just don’t work as well) are a commonly-used attractant for human-feeding mosquitoes, so it works well enough as a “human” smell for some of our ectoparasites.” It may be that really sweaty socks are used as an attractant, but, really, how do they know that those arthropods are not somehow attracted to some other aspect of the bacteria growing on those socks, and not some human odor? (I also note that synthetic materials are not as conducive to bacterial growth!). How do we know that these mosquitoes and spiders are not tagging on the bacteria themselves? I somehow doubt that such a test had been done, and that these shoddy researchers have just assumed that this is a valid indicator.

It is always valuable to look beneath the unexamined assumptions of various studies.

Da Nile

December 17, 2010

It’s more than just a river in Egypt.

A week ago there was an article in The Detroit News entitled Barefoot craze hits everyday footwear. It’s mainly just a plug for a shoe made by Sanuk that they call a “Sidewalk Sandal”. It is yet another minimal support shoe (though, of course, it is not barefoot). I suppose if you have to wear something on your feet for your job, it’s better than nothing. (Huh? What am I saying? Of course, nothing is better. Let me try again: if you have to wear something on your feet for your job, it is probably among the least burdensome. How’s that? But I digress.)

But then the article makes the mistake of talking to the usual coterie of barefoot-ignorant and barefoot-hostile podiatrists:

Podiatrists aren’t thrilled with this celebration of shoelessness. People wear shoes, they say, because in modern society they need them.

Really? Why? Any support for this? Of course not.

Few people have an ideal foot type that doesn’t require support, said Brett Sachs, a Wheat Ridge, Colo., podiatrist. “Most people I see are ones who have flat feet or high arches or are getting other types of symptoms related to the fact they don’t have the support their feet should provide them and stress is getting redistributed to other parts of the body.”

Now this is just crap. How the heck did our remote ancestors ever manage to survive? Practically everybody has an ideal foot type that doesn’t require support. That’s the way evolution works. That’s what was found in the Hoffman study I often cite. This guy, in his daily practice, sees nothing but feet that have problems because they spend all their time in stiff-soled shoes that make them dependent upon getting support. And then he thinks that feet are naturally that way.

I’m reminded of how, for the longest time, it was thought that back belts were the way to go to prevent job-related back injuries. Everybody knew it. Until an actual study was done. A Prospective Study of Back Belts for Prevention of Back Pain and Injury, by James T. Wassell, et al. in The Journal of the American Medical Associationa, December 6, 2000, Vol. 284, No. 21, p. 2727, found no effect at all.

Barefoot advocates say going shoeless makes them feel more powerful, but Clinton Holland, an Englewood, Colo., podiatrist, doesn’t buy it.

“The whole idea of strengthening your feet by not wearing shoes, there’s nothing that backs that up,” he said. But he’s not opposed to shrinking from support.

“I tell patients, if it helps you, do it,” he says. “If it feels better, then knock yourself out.”

OK, I’ve read few things quite as moronical. He is basically saying that exercising a body part will not strengthen it. Really? But it is so nice (and condescending) of him to let us know that he will deign to let us go barefoot. It would be nice, though, if he recognized the limits of his practice.

I’ve mentioned before that podiatrists rarely see people who go barefoot all the time, so they just don’t have experience in the area. When they were in medical school, the learned tons of information, but all that information had been distilled for them (that’s what medical school does—distills and presents the information they need in their practice), and that information had been based on studying a shod population. And when it comes to barefooting, they are operating outside of their field of expertise and often don’t even know it.

It is kind of like examples we see on Monsters Inside Me in which somebody picks up some tropical parasite, and that person has to go through a whole slew of doctors before they find one who actually knows what is going on.

Immune System

December 15, 2010

Over at the Facebook page for The Barefoot Book, author Daniel Howell asks:

Is there a connection between shoes & immunity? Many long-time barefooters report stronger immune systems.

I answered:

I’d be very careful generalizing. This is one area in which confirmation bias could be very, very strong, and an area in which one should be suspicious of anecdotes. I think a careful study with decent controls would really be needed to tease out any effect.

Let me go into more detail here.

First of all, what is confirmation bias? It is the tendency for humans to remember things that agree with what they already think and to forget those that disagree. This effect has been well-demonstrated in many cognitive studies. So, what we need to do is conduct well-designed studies that remove such bias.

Quite a few barefooters report fewer colds since they started going barefoot. Could that be from a barefoot-induced improved immune system? Well, I suppose it’s possible, but I personally tend to doubt it.

I’ve noticed that I tend to get fewer colds since going barefoot. But let me note how confirmation bias and other confounding factors could work into that. First, I have not kept careful track of my colds over the past years, so I really don’t know if I am getting fewer of them now. It may seem that way to me, but without accurate records, that could just be confirmation bias. Second, my kids are older now and have (mostly) left the house. When they were really little, it seems they were always bringing a cold home, and of course I’d catch it. As they grew older, they didn’t need such close care, and were much more careful about covering their noses when they sneezed, so transmission vectors were reduced. And now with them mostly out of the house, the opportunity for catching something from them is really, really reduced.

Now, that period coincides with my taking up barefooting. Without decent controls, it would be easy to attribute fewer colds to barefooting instead of what is the more likely explanation: fewer chances to get a cold.

There is also the question of mechanism. How might going barefooting increase the efficacy of the immune system when it comes to colds? Without at least a scientifically plausible mechanism, it all seems unlikely. I can think of two possible mechanisms, both fairly weak. First, we’ve noted that going barefoot can improve circulation. Maybe that does something, but the circulation is really only in the feet, and I don’t see how a cold virus would notice that, or how that would effectively raise the immune system. Second, and this one is more plausible, stress has been shown to depress the immune system. So if going barefoot gives you a better feeling of contentment and reduces stress, then it could improve your immune system. I’m not sure this is a really strong effect, though.

So, this is why I say it would really take a decent study to figure it all out.

So far I’ve focused only on colds. There are other areas in which I think barefooting might have a larger impact on the immune system. One reason may be the Hygiene Hypothesis, which suggests that an overly clean environment, one that our ancestors did not have, might insufficiently stimulate the immune system and lead to allergies. Of course, if you go barefoot, your body is physically exposed to a lot of dirt, so it could help with allergies.

In addition, there is the famous anecdote of the guy who cured himself of a severe allergy by infecting himself with hookworm. There has also been a study backing that up.

I can see another way the immune system could be strengthened. For all the hiking I do, I do occasionally get small dings on my foot, and those dings come into direct contact with the soil and soil micro-organisms. Of course, my immune system has to react to that. What I seem to have noticed is that (look out for confirmation bias!) while originally I would get some redness as my immune system had to develop new antibodies, the more I barefooted, the less redness would result, presumably because my body could call upon my pre-existing antibodies against those soil bacteria. That could come in handy if my body gets exposed to such bacteria in other contexts, and might give me an immunological advantage over a person who had not had such previous exposure.

Bottom line: there is some possible anecdotal evidence, but it needs to be backed up with carefully designed studies.

Flat Feet versus Fallen Arches

December 8, 2010

A couple of weeks ago, over at America’s Podiatrist, Dr. Nirenberg asked, “Can Barefoot Running & Walking Fix Flat Feet?” He references a study, The Influence of Footwear on the Prevalence of Flat Foot: A Survey of 2300 Children, by Udaya Bhaskara Rao and Benjamin Joseph (The Journal of Bone and Joint Surgery, Vol. 74-B, No. 4, July 1992, p. 525. The study was conducted on children in India.

Below is the criteria they used for grading an arch as high, normal, or flat:

Definitions of arch types

What they found was that while 2.8% of the children who went barefoot all the time had “flat” feet, 8.6% of those who wore footwear had “flat” feet. They also found that the more shoe-like the footwear, the more of the children had “flat” feet.

There was a related study done a few years later, “The Influence of Footwear on the Prevalence of Flat Foot: A Survey of 1846 Skeletally Mature Adults“, by V. Sachithanandam and Benjamin Joseph (The Journal of Bone and Joint Surgery, Vol. 77-B, No. 2, March 1995, p. 254. In this one, they compared the prevalence of flat feet based on the reported age at which the adult started wearing shoes. They found a 1.75% rate of flat feet in those who didn’t start wearing shoes until over the age of 16, and about 3.25% for those who started wearing shoes earlier.

It sure looks like wearing shoes contributes to a lower arch.

But what does that have to do with flat feet? Many folks confuse a flat foot (that is, a foot with a low arch) with fallen arches. In fact, Dr. Nirenberg says as much as he starts his blog entry:

Flat feet is a condition where the arch of the feet undergo collapse and flatten: That is why it is often also referred to as fallen arches. Individuals with flat feet can suffer from a variety of foot ailments, pain, and fatigue, which can also extend to the legs and back.

I do not think this correctly describes the situation. To understand what is going on, we have to go way back to a much earlier study, “Conclusions Drawn from a Comparative Study of the Feet of Barefooted and Shoe-wearing Peoples, by Phil. Hoffman, M.D., St. Louis. (The American Journal of Orthopedic Surgery (1905)). Dr. Hoffman had a chance to examine barefoot natives at the Louisiana Purchase Exposition in 1904. He checked their arches and found a fair proportion of them did have low arches. However, and this is important, he did not see any pathologies associated with those “flat” feet. As he put it

If these statistics are a fair index for all feet, the conclusion is justified that weakness of the longitudinal arch rarely results in its depression, and that flat foot as a pathological entity hardly exists.

The height of the arch appeared to bear no relationship to the gait. In shoe-wearers, the affection commonly called flat foot is often associated with more than ordinary eversion of the foot on standing and walking. This eversion is due not to the low arch, but to the associated weakness or stiffness of the joints of the foot and weakness of the muscles controlling them.

In other words, among the barefooted, having a low arch, or “flat” feet, has nothing to do with whether you have a “fallen” or “weak” arch. A weak or fallen arch, a result of wearing shoes and thereby failing to keep those muscles and tendons and ligaments strong (also pointed out by Dr. Nirenberg), is a different condition than merely having a flat foot (or naturally low arch).

So, can walking and running barefoot fix a flat foot? No. But can it fix a fallen arch? Almost assuredly. Will it raise the arch? Maybe.

Obviously, as any physical therapist can tell you, using a previously inactive body part will strengthen it. It will not only strengthen that part, but all the other parts associated with it. Muscles, bones, ligaments, tendons will all respond to the greater use. I can see how it would be possible that toning all those parts could raise the arch as they are all strengthened. Obviously, there is some anecdotal evidence that this is so, but I’ve not seen studies that demonstrate it.

However, as the Hoffman study shows, who cares? It doesn’t matter! It’s not the height of the arch that matters, it is the underlying physiological structure, and you get that from going barefoot whether your arch rises or not.

In my own case, I have no idea if my arches are really raised since I started going barefoot. They do look raised, though. However, much of that just could be the appearance caused by the much thicker pads on my feet now. Since the pads get thicker on the non-arch parts of the foot, that can give the appearance of a higher arch.

One more point: There are reports of over-use injuries in those who just start going barefoot. These are the sorts of people who try to run long distance before all the muscles and bones and stuff have had a chance to properly strengthen (this can take around 6 weeks, and probably it is not fully there until 6 months). Since I also play tennis, I can relate this to tennis. If you never played tennis before and suddenly picked up the sport and starting playing hours on end, hitting as hard as you can, you have a very good chance of picking up tennis elbow. The parts of your arm need strengthening first, and it has to be worked up to (it also helps to work on technique!). Same with any sort of extended or extreme barefooting.

Athlete’s Foot

December 1, 2010

Those concerned about bare feet always seem to mention athlete’s foot. Here is part of a Question and Answer from Dermatology Insights, Volume 3, Number 1, page 30 (2002). It was published by American Academy of Dermatology. I’ve emphasized some of the text:

Q: Why does athlete’s foot develop?

A: Athlete’s foot is a term used to describe a fungus infection of the feet. The correct term for athlete’s foot is tinea pedis. The fungi that cause athlete’s foot grow in moist, damp places. Sweaty feet, not drying feet well after swimming or bathing, tight shoes and socks, and a warm climate all contribute to the development of athlete’s foot. It’s commonly believed that athlete’s foot is highly contagious — that you can easily catch it from walking barefoot in the locker room. This is not true. Experiments to infect healthy skin with athlete’s foot have failed and often one family member may have it without infecting others living in the same house. It’s not clear why some people develop athlete’s foot and others don’t.

. . .

Q: How can you prevent athlete’s foot?

A: Wash your feet daily, and always dry your feet thoroughly, especially in between your toes. Avoid tight footwear, especially in the summer. Sandals are the best warm weather footwear. You should also use an anti-fungal powder on your feet and in your shoes during the summer. Alternate shoes so that they have a chance to dry out at least 24 hours before re-wearing them. Cotton socks (or socks made of a material that takes moisture away from the skin) are best and you should change them if they become damp. Whenever possible, go barefoot at home. Athlete’s foot does not occur among people who traditionally go barefoot. It’s moisture, sweating and lack of proper ventilation of the feet that present the perfect setting for the fungus of athlete’s foot to grow.

I might add that going barefoot all the time, not just at home, is even better.

Also, this is the source of the quote about athlete’s foot on the web page of The Society for Barefoot Living.

Did Cavemen Get Athlete’s Foot?

November 21, 2010

That’s the title of one of the sections of the FYI feature in the December 2010 issue of Popular Science (p. 102).

Yours truly is quoted in it:

But just walking around in fungus doesn’t cause athlete’s foot. Cavemen would have had to have worn shoes. “It turns out that athlete’s foot is a disease of shod populations,” says Bob Neinast, the lead blogger for the Society for Barefoot Living. “Anyone can pick up the fungus, but the thing to keep in mind is that it grows really well in a warm, dark, moist environment. That’s the inside of a shoe.” People who go barefoot, Neinast says, rarely get athlete’s foot, most likely because exposure to fresh air keeps their feet too dry for the fungus to take hold and multiply.

The article then goes on to ask if cavemen actually went barefoot. People (or at least some people) have probably been wearing footwear for at least 40,000 years. According to scientific papers by Erik Trinkhaus, you can tell if people are wearing shoes because the toes, which are used quite a bit by barefoot people, have smaller bones in the shod. Those papers are Anatomical evidence for the antiquity of human footwear use and Anatomical evidence for the antiquity of human footwear: Tianyuan and Sunghir. But also don’t forget that, for most people back then and for a long time, shoes were expensive. They would probably only be worn when really needed.

Anyways, the Popular Science article then goes on to talk to Cody Lundin, of Dual Survivor fame. He suggests that, if they did get athlete’s foot, they might have had a remedy:

If you take the green parts of a juniper plant and boil them, the mix makes a wonderful fungicide that will work on athlete’s foot. Indigenous people might have used it. Works great on jock itch, too.

Of course, being a barefooter, I have no need of it.

You can read the full article in Popular Science.

Footsore

October 10, 2010

Bare feet are not a panacea. Like any other part of the body, they can be overworked. While going barefooted offers relief from many of the inflictions of shoes, sometimes shoes are tools (just as many articles of clothing are tools) that can extend our capabilities. But I prefer that the choice between the two be a balancing, and a conscious choice.

That said, you may be guessing (correctly) that I am a bit footsore at the moment. On Thursday I did a 12-mile hike. This is farther than I managed to hike during the entire month of September. So, I was a bit out of shape, and my feet were definitely out of shape.

I actually had no problem during the hike. I was down at Lake Hope State Park. There are a bunch of trails just north of the lake. These have a bit of scree, and with the recent lack of rain, the ground is fairly hard, so the trails can be a bit of a challenge. Nonetheless, as I said, I really didn’t have much problem. I think part of that is that the body, while in use, builds up endorphins during use, and it is only after they have faded away that one feels the aftereffects.

Which I did.

On Friday I was footsore. You will usually see references to “footsore” in Civil War reminiscences, since many of the Confederate forces (and some Union ones) were barefoot and did long marches so. But I’ve also seen references to shod soldiers getting footsore, too. (And I’ve read a lot about shod soldiers getting blisters from their shoes, something that happens quite rarely to the barefooted). I still had no problem getting around; it is just that if I tried to walk on a more knobby surface, I had to take it slowly and easily.

On Saturday and Sunday, though, the Columbus Metroparks System was putting on a few guided hikes at Clear Creek Metro Park. So I was a bit worried if I might be able to handle those hikes.

I need not have worried. By Saturday morning, my soles were still just a bit tender, so I took a dose of ibuprofen. And that was that. The hike started for a short bit on a gravel road. I made sure to walk on the less gravelly parts, and only got zinged once or twice. After that, the hike (a fairly short 2 miles) was off-trail on forest detritus, mostly leaves. And it was wonderful.

Sunday’s hike was similar, though it was on a regular path. By now there was just a minor reminder of being footsore. Again, there were patches of dry and hard soil, and pebbles. Again, I started the hike with some ibuprofen (just in case), but once I got into it, the endorphins kicked in again, and I was comfortable. Again, it was a wonderful hike.

It’s not too surprising that being footsore cannot last too long. For any of our remote ancestors, anyone who was really hobbled by long walks would not have survived very long to produce ancestors. And while it has been a while since (at least) my ancestors did such long-distance barefoot traveling, that capability still resides within us.

There is a famous passage in about the adaptability of feet in a scientific paper by Samuel Shulman, “Survey in China and India of Feet that have Never Worn Shoes,” The Journal of the National Association of Chiropodists (1949):

One hundred and eighteen of those interviewed were rickshaw coolies. Because these men spend very long hours each day on cobblestone or other hard roads pulling their passengers at a run it was of particular interest to survey them. If anything, their feet were more perfect than the others. All of them, however, gave a history of much pain and swelling of the foot and ankle during the first few days of work as a rickshaw puller. But after a rest of two days or a week’s more work on their feet, the pain and swelling passed away and never returned again. There is no occupation more strenuous for the feet than trotting a rickshaw on hard pavement for many hours each day yet these men do it without pain or pathology.

Yup. It takes just a bit to build one’s feet back up. And now I’m off to play some barefoot tennis, footsore no more.

[Update: Tennis went just fine, but that was on a smooth hardcourt surface. What still bothers me is my driveway, which is old asphalt with quite a bit of gravel sticking up. I still feel that and have to walk gingerly. It still feels a lot better than putting on shoes.]

A Barefoot Running Injury Epidemic?

May 29, 2010

Here is a new article talking about The Barefoot Running Injury Epidemic. The author notes

Darwin Fogt, PT, owner of Evolution Physical Therapy in Culver City, CA, is alarmed by a stark new trend at his facility: runners with injuries caused by barefoot (or virtually barefoot) running. Fogt says he has four or five current patients with heel injuries clearly resulting from a switch to barefoot running and has recently treated another 12 to 15 others.

These injuries are happening both for real and fake barefoot runners. (Yeah, I’m using “fake” to gently tweak those who call running in shoes such as Vibrams “barefoot”.) The article does wonder whether the increase is due solely to the increase in barefoot running, due to books such as Christopher McDougall’s Born to Run. If all runners are getting injured at the same rate, but there are more barefoot runners now, one would expect there to be more injured barefoot runners.

But I suspect that there is more going on. Others, such as Ken Bob Saxton, note that if you try to start minimalist running in things like Vibrams, you will not be getting good feedback from your soles, which can tell you when you are overdoing it. How the heck are the runners being discussed getting specifically heel injuries? About the only way to do that is to run barefoot as if you are still wearing shoes.

There is something else, too. If you just go right out and try to run barefoot after having encased your feet in shoes for 20-50 years, you should expect the internal muscles, tendons, ligaments, and bones to look just as pasty as the outsides of your feet. It is well known that you have to use your body to strengthen it. Shoes are crutches; shoes are support. When you take your feet out of shoes, they will be weak. Incredibly weak.

It’s like taking your leg out of a cast. You wouldn’t expect to be able to do weightlifting or sprinting, yet people take their feet out of shoes and expect to immediately be able to run just like they did with their support. Instead, you really do have to work up to it. Just as when you get a cast off, you have to undergo rehabilitation in order to regain strength and the underlying supportive tissue, so too do your feet need similar rehab.

You also need to retrain your brain. If you run in shoes, you’ve learned a specific way to run in them. That won’t necessarily work when you run barefoot. If you had started as a kid, you would have slowly and methodically worked out the right technique, but if you take your adult technique and try to retrofit it to barefoot running, it’s no wonder things don’t necessarily work right.

We Need to Lead Reporters by the Nose

April 4, 2010

There is a nice CNN iReport that talks to Julian Romero about barefoot running. It hits all the usual high points about how it is better for your feet, and that it doesn’t make your feet all ugly looking (which seems to be a common misunderstanding). Julian does a very good job.

Now, iReports are created by average people, not reporters, but if CNN likes them, they will “vet” them, and add the CNN logo to the ones they have vetted. This video is one of those.

While the video is fine, the accompanying text suffers from the usual defect that reporters indulge in. The final paragraph of the text says:

What would a Doctor say about the health risks of running barefoot. I spoke with Doctor Fred Nicola, Orthopedic Surgeon and team physician for the Oakland Raiders. Dr. Nicola said, “Barefoot running is acceptable when running short distances on dirt, grass, or track. Long distance running, especially on payment, is not good. It can cause long term damage” Long term damage can include; “plantar fasciisitis, ankle and mid foot arthritis, and serious tendonitis, which can lead to severe foot problems” He also said, “as you get older you loose the natural cushioning on the sole of the foot, and wearing an adequate shoe with support and cushioning will protect the natural foot arches, and protect against damage caused by repetitive impact”.

Dr. Nicola does not agree that it is better for the average runner to go barefoot, but,” for some subsets of runners it may be acceptable.

It’s the usual entrenched podiatrist position, offered without the podiatrist having any experience in the subject matter.

I have no idea, because of the iReport format, whether Julian would have had any chance to sway such a comment, so this is not intended as any criticism of him. But what I’d like to do is offer to folks some suggestions for something to do if you are ever interviewed by a reporter.

You have to keep in mind that “journalism” these days suffers from “he said, she said” syndrome. That is, the reporter seems to think they are doing their job if, after talking to one person, they find another person with an opposing point of view. The reporters make no effort to find out which person has the facts on their side (much of political discourse seems to be driven by this lack of fact-finding).

Thus, I’d like to offer the following points to bring up when talking to a reporter:

Just a couple of suggestions that might improve the accuracy of these media stories.


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