When Liu Liping heard this, she couldn't help but feel a little deflated, but after thinking about it, she asked Xu Yi again: "Then according to what you say, if I use normal saline as a mask, won't it be able to avoid the loss of ions in the stratum corneum, will this make the hydration faster, but will this affect the metabolism of deep tissues?"

Xu Yi shook his head: "Actually, it may not be of much use, no matter what kind of mask it is, not everyone will have an effect if they use it." ”

"Why?"

"How good a person's skin is, the most important influencing factor is the innate basis, plus the age factor, these are the fundamental factors that determine the quality of the skin. Even the best elderly people can hardly compare their skin with the worst skin compared to the worst adolescent children. In addition, the skin is also subject to a variety of factors such as environment, lifestyle habits and individual health level, and hydration can only solve the problem of skin dehydration, and nothing else can solve it. ”

Glancing at Liu Liping, Xu Yi continued: "As for you, I don't think it's worth doing it or not. You're still having acne, which is naturally due to a bacterial infection, and it also proves that your sebum production is a little too much. When there is a lot of sebum secretion, the skin's moisture retention performance is naturally good. As a student, most of the activities are indoors, outdoor activities are limited, and the nutritional status is not too good, so the lack of water in the skin may not be much. Even if you use moisturizer, it is not even good, after all, this thing also contains esters, which can make the acne on your face worse. ”

"Ah, is that so?" Liu Liping nodded.

Xu Yi nodded, and then said, "But if you want to make a salt water mask." I wouldn't strongly disagree, after all, it's just a way to hydrate. A little more and less water has not had such a big impact on the human body, and it has not rained in the provincial capital during this time. The air is naturally relatively dry, and most people will be more or less dry. At least people can feel more comfortable and feel better when making a mask. ”

"As for the hydrating effect, this saline solution will definitely be better than water, and the effect will naturally be longer-lasting, and it can still be slightly useful for some people with thick stratum corneum or a large number of cosmetics. As for the possibility of normal tissues, normal cells have the ability to self-regulate, so that this little salt water can affect anything.

"It's like going to the beach for a swim and jumping off a big living person. It is common for people to grow a groping pig hand to take advantage of a woman, but it is basically impossible to turn the whole person into a large piece of salted meat. ”

When Liu Liping heard this, she put her mind at ease and thought about trying to make a mask with saline next time, but then asked: "When you talk about seawater, I remember that people always say that it is easy to get sunburned by the sea." So why is it easy to get sunburned when swimming at the beach, is it because the summer is closer to the sun and the ultraviolet rays on the beach are stronger?"

Without waiting for Xu Yi to say anything, the fat man rushed to answer next to him: "I know this question!"

White-eyed fat man. Liu Liping said: "If you know it, just say it, but even if you don't speak, no one will sell you as a dumb person!"

The fat man said on the side: "Hehe, the seasonal change in the distance between the sun and the earth is actually negligible relative to the radius of the Earth's orbit. The biggest change is actually the angle between the sun and the earth. In summer, the angle is small, so the distance through the atmosphere is also shorter, so there is more ultraviolet light left. Third. Isn't that so?"

Seeing Xu Yi nodding, Liu Liping turned her head and asked the fat man, "Then what?"

The fat man grinned and said, "The rest of the questions are too simple. Do you still need me to explain this to you, third child!"

"No, it won't. Still pretending to be a big-tailed wolf!" Liu Liping turned her head to look at Xu Yi.

Xu Yi has never been to the beach, except for seeing some related diseases, there are only some theoretical things left, so he said with a smile: "I have never been to the beach, so I have to analyze it in combination with some patients and theories I have seen." ”

"Anyway, it's just chatting, and it's not for you to see a doctor, so there's no need to be so serious. ”

Xu Yi organized the language and said, "Many people say that the sea is strong because the beach and the sea surface reflect a lot of ultraviolet rays, plus the air is relatively clean, so it is particularly easy to sunburn, but I think it should not be so simple to look at this problem." ”

"What do you think?"

"Any kind of disease is often caused by a combination of factors, even if you accidentally break your foot when walking on a flat road, it is because of your own physiological defect such as laxity of ligaments, so even if it is sunburn, it is also caused by many factors. As he spoke, Xu Yi pointed to the door and said, "Just like this riverside, people come and go, and it's still sunny during this time, how many trees are there here, the open river, and the exterior decoration of those buildings, doesn't it still reflect ultraviolet rays, but have you heard of which one got sunburned after going back?"

Then Xu Yi asked again: "Xiao Liu, have you noticed where most of these people are sunburned?"

Liu Liping shook her head.

Xu Yi pointed to his body and said: "Most of the lesions in solar dermatitis are actually mainly on the shoulders and back, plus the outside of the two upper arms, but very few people get sunburned on their faces, do you know why?"

"Hey, isn't that about the same as a half-sleeve?"

Xu Yi smiled and nodded, "Yes, think about it again." ”

Liu Liping tried to give the answer: "Do you want to say that these places are places that are not often exposed to sunlight?"

Xu Yi nodded. "That's it, partly because these places don't have a lot of sunlight, and on the other hand, I think it's inseparable from the sea. ”

"Why?"

"There will be no one who dresses tightly to go to the beach, going to the bath will naturally be soaked in water for a long time, especially the shoulders and back, on the one hand, it is responsible for the movement of the upper limbs, on the other hand, it is necessary to keep the head above the water, which will naturally have a process of repeated soaking and repeated exposure, and even more, after going ashore, there are still people who do not wash, and then move in the sun, what do you say?"

Liu Liping shook her head. "I've never been to the beach either. I don't know. ”

"Fatty, what about you?"

Naturally, the fat man has been to the beach. said: "Anyway, it's just a white flower, and the body is dry." It wasn't comfortable at all, and I definitely went to rinse it. ”

Xu Yi smiled and nodded: "These white flowers are all crystals of salt, after a long time of contact with the skin, this salt will definitely penetrate into the skin, and this time will inevitably affect the salt content of the extracellular fluid in the skin." In order to adapt to the high and deep environment, skin cells will naturally exude outward, which is actually equivalent to dehydrating the cells. ”

"Short-term dehydration will not have much effect, but if the dehydration time is too long, it will inevitably affect the metabolism of cells. It will definitely cause some damage to skin cells. If you want to dehydrate the damaged cells, coupled with the ionization effect of ultraviolet rays, it will inevitably be easier to damage the skin, so it will naturally be more susceptible to sunburn at the beach. ”

Hu Yifei nodded and said, "You seem to have a certain truth in saying this, otherwise, our school's open-air swimming pool has been open for so long, and I haven't heard of a few sunburns." ”

Yan Peimin asked: "Does this have nothing to do with temperature? I always thought it had something to do with temperature." ”

Xu Yi smiled but didn't say anything, turned his head and asked Hu Yifei: "Boss, have you ever encountered electro-optic ophthalmia and electro-optic dermatitis during your internship?"

Hu Yifei nodded. Naturally, these people are often seen in the outpatient clinic.

After all, this is the time of rapid development of the provincial capital, and many migrant workers are recruited and go to work after simple training, and sometimes they don't understand this protection problem, and it is inevitable that there will be the basis for these diseases when they meet the black-hearted boss again.

"Then you notice that except for children, they don't understand. Looking at the ultraviolet lamp or the electro-optic ophthalmia caused by others burning electric welding, if it is a welder who has electro-optic dermatitis, most of them have electro-optic ophthalmitis. Not necessarily, and there are far more people with electro-optic ophthalmia than electro-optic dermatitis?"

Hu Yifei thought for a moment. "If you want to say that, that's true. ”

Xu Yi began to explain Yan Peimin's problem: "In fact, whether it is snow blindness, electro-optic ophthalmia, or electro-optic dermatitis. The essence is all the same. They are the result of acute damage to the cornea, conjunctiva or skin caused by large amounts of ultraviolet light. If it is related to temperature, this is obviously not true, not to say that snow blindness must be below zero when it occurs, just to say that the eyeball is also bare on the surface of the body, and there are tear glands to help moisten, and the surface temperature will obviously be lower than the skin. Therefore, this solar dermatitis must have nothing to do with the temperature, but it can only be said that this may also be because the sun shines on the skin, and the temperature can not spread in time, which increases the damage to the skin, thus aggravating the damage of solar dermatitis. ”

Liu Liping listened on the side, and felt a little fresh when she heard the word snow blindness, so she asked: "Third child, what is snow blindness, why have I never heard of this problem, is it blind when I see snow?"

Xu Yi smiled and shook his head: "We don't have much snow here in a year, and there are basically very few snow blinds." The reflectivity of the snow to sunlight can reach more than 90 percent, if you look at the snow for a long time, it will make the cornea and conjunctiva receive excessive ultraviolet radiation, after a few hours of incubation period, the patient has red and swollen eyelids, conjunctival hyperemia and edema, severe foreign body sensation and pain, fear of light, tearing and inability to open the eyes. ”

"Isn't it that I can't see clearly, and this doesn't affect the retina?"

Hu Yifei shook his head with a smile and said, "Of course not, this is the most common result of inflammatory exudation, the result of reduced corneal permeability, and the same is true of electro-optic ophthalmitis. ”

Xu Yi nodded. "Only a very small number of people with snow blindness will have damage to the retina, but this is extremely rare. The pupils can adjust the light that comes in, and if you're walking and the headlights are turned on by a car on the opposite side, you're definitely going to have to squint and look ahead. The snow is so bright, it exceeds the ability of pupil adjustment, why do you have to stare at things without heart?"

The fat man shouted next to him: "So that's the case, this screenwriter is really a cheat." (To be continued......)

PS: I'm sorry, I'm sorry, I thought I uploaded it yesterday, and I just found that it wasn't uploaded when I came back from shopping.