△ Video: "Challenge Impossible"

CCTV News:Today is "119" Fire Day, and some people call fire fighters "retrograde heroes", because whenever there is a crisis, all people are retreating backwards, and only fire officers and soldiers are going retrograde. Touched by the spirit of courage to take responsibility and dedication for these lovely people, their superb skills are also impressive and admirable.

No, recently, an armed police fire fighter in Gansu province showed his exquisite skill of blindly cutting steel wires on light bulbs with a toothless saw in the inspirational program "Challenge Impossible".

Fire fighters blindly cut steel wire bulbs on the bulbs without any damage.

The soldier’s name is Li Haifeng, and his challenge is to blindly cut the steel wire fixed above the light bulb through a thick steel plate with a toothless saw.

△ Toothless saw

The distance between the steel wire and the bulb is only 0.01 mm.

After 45 seconds, the steel wire broke with a bang, and Li Haifeng quickly received the force, and the light bulb was not damaged at all.

In the end, Li Haifeng challenged successfully and won applause and exclamations at the scene. Of course, such skills are not limited to stage performances, but are more used in Li Haifeng’s rescue work.

For example, once, a 16-year-old boy couldn’t get the ring off his hand. After trying to cut the ring with tools such as steel bar breaker, pliers and saw, Li Haifeng decided to use a toothless saw.

He wrapped the boy’s hand with a towel in order to prevent the sparks from cutting from hurting his skin. During the cutting process, he kept watering the boy’s hands to cool down because of the fever.

In the end, Li Haifeng sawed off the ring with a toothless saw and successfully saved the boy’s finger.

After 17 years of practice, I have developed an extraordinary stunt.

When Li Haifeng challenged to cut the steel wire, he relied on hearing and touch. He said, "The right ear captures the sound of the engine, and the left ear distinguishes the friction of the grinding wheel." The summary of a short sentence embodies the sweat and hardships of 17 years.

In 1999, 19-year-old Li Haifeng joined the army from Hebei and became a fire fighter of Gansu Baiyin Fire Brigade. A few years before joining the army, Li Haifeng has been the squad leader of the rescue class, specializing in demolition technology. In 2010, he began to try to cut the steel wire on the light bulb with a toothless saw. From the initial watching to the later blindfolded cutting, Li Haifeng exchanged three years of tenacity and sweat for the unique skills in the country today.

"In three years, I chopped up more than 1,000 light bulbs." Li Haifeng said that from the initial lack of confidence and the discouragement of countless failures, he experienced painful hardships again and again. "Now, I have formed a deep feeling with the light bulb."

Facing the test of life and death, be a pioneer in emergency rescue again and again.

Since joining the army at the end of 1999, this military uniform has given Li Haifeng a strong sense of mission. At the age of 36, he rescued 188 people in distress, protected tens of millions of materials and property, and won many honors. He is currently the deputy director of the training department of Gansu Provincial Public Security Fire Brigade, and his injuries are as many as the awards he won.

Over-training and accidents in many rescue accidents, Li Haifeng suffered six fractures, numerous minor injuries, severe varicose veins in both legs, and unbearable pain at the fracture site every cloudy day. And he said: "There will be a lot of aerial work in fire fighting and rescue, and there will be many accidents in emergency rescue, which will inevitably lead to sprains and bruises, which is normal."

△ Li Haifeng blindly cut the steel wire fixed above the bulb through a thick steel plate with a toothless saw.

Now I have a skill, but I was afraid at the beginning. Li Haifeng recalled that in 2000, not long after he joined the army, he once performed a extinguishing task, and the squad leader asked Li Haifeng to set up the gas tank. "After the rescue of personnel was completed, in the face of the explosion of liquefied gas at any time, at the moment when all firefighters were ready to evacuate, the captain asked me to help the liquefied gas tank immediately. To be honest, I hesitated for a moment, because I was really scared. The liquefied gas tank was still breathing fire and could explode at any time. " Despite his inner fear, Li Haifeng did it at once. Just turning 20, he felt as if he had passed by death.

△ Li Haifeng participated in the second season of "Challenge Impossible".

I have participated in various rescues for more than 3,000 times in 17 years, but the more I have seen life and death, the deeper I feel awe. "I remember a multi-person car accident in Baiyin No.1 Road in 2013. When we rescued one of the ladies, she had no signs of life. At that time, her son kept crying, and her husband immediately knelt down and kept kowtowing to us and begged us to save her. At that time, I felt my heart was bleeding, and I really felt very ‘ Incompetence ’ . Life is particularly fragile, and all fame and fortune are not important in front of life. "

This job also gives Li Haifeng few opportunities to reunite with his family. Li Haifeng’s wife said in the program, "Although we get together less and leave more, the day we marry Li Haifeng, we are ready for all the psychological preparations we need to bear as a military spouse." A simple sentence made the host Dong Qing and many viewers shed tears on the spot.

Li Haifeng’s soul-shaking skill display is precisely because of his deep sense of responsibility and mission. He explained the word "hero" in peacetime with the most practical actions.

Benmao

Cloned cat

　　On the 19th of this month, the first commercial cloned cat in China was officially announced. This cloned cat named "Garlic" was born on July 21st this year. "Garlic" is also the first cloned cat in China.

　　It is understood that Huang Yu, the owner of the cloned cat "Garlic", chose cloning technology to restart a new life in order to commemorate the dead pet cat. This cloned cat was born on July 21st through natural delivery of surrogate cats.

　　Is the cloned cat "Garlic" the same as the deceased pet cat? Why is the coat color changed? Weekly reporter interviewed experts from Jiangsu Key Laboratory of Xenotransplantation to reveal the story behind cloning.

　　Cloning: the asexual reproduction of an organism

　　In 1963, Haldane, a population geneticist, first put forward the term "cloning" in a speech entitled "Biological Possibility of Human Race in the Next 20,000 Years".

　　In 1997, the news that a sheep named Dolly was born through cloning technology immediately attracted the attention of all over the world. Since then, cloning has become a hot topic for everyone.

　　Clone is a transliteration of the English word clone. Its original meaning refers to the cultivation of plants by asexual propagation or vegetative propagation of seedlings and shoots. With the passage of time, the connotation of cloning has expanded, which generally refers to the asexual reproduction of organisms through somatic cells and the population composed of offspring individuals with the same genotype formed by asexual reproduction; Usually, individuals or populations with exactly the same genes as the original individuals are produced by asexual reproduction using biotechnology.

　　In fact, cloning is no stranger to us. We often use this biological method of asexual reproduction in our daily life. For example, whenever spring blossoms, people who like to plant flowers and grass will do experiments in plant cutting. From a plant, cutting branches and cutting will get many plants with the same genetic material, which is cloning. Asexual reproduction is more common in lower organisms. The division and reproduction of bacteria and planarian is that the parent splits vertically or horizontally into two daughters, and then leaves the parent and becomes an independent individual, which also belongs to cloning.

　　However, does asexual reproduction exist in higher organisms? Scientists once thought that it was impossible to reproduce asexually from a mature somatic cell into a complete animal. Although a somatic cell contains a complete genetic information of an animal, somatic cells have been specialized. Generally speaking, liver cells can only produce liver tissue, and breast cells can only produce breast tissue … … The birth of Dolly sheep completely changed people’s understanding, and it pioneered the cloning of higher animals.

　　"First, the nucleus of a donor cell containing genetic material is transplanted into an egg cell with its nucleus removed, and then the two cells are integrated by micro-current stimulation, and then this new cell is promoted to divide and reproduce and develop into an embryo. When the embryo develops to a certain extent, it is implanted into the uterus of a surrogate animal to make the animal pregnant, and an animal with the same gene as the donor can be born." Li Rongfeng, a researcher at Jiangsu Provincial Key Laboratory of Xenotransplantation, introduced the cloning process of higher organisms.

　　She said that cloning technology does not need male-female mating, and does not need the combination of sperm and eggs. It only needs to extract a single cell from an animal, cultivate it into an embryo by artificial methods, and then implant the embryo into a female animal to breed a new individual. This cloned animal cultured with single cells has exactly the same characteristics as the single cell donor and is a "replica" of the single cell donor. Scientists in England and Oregon in the United States have successively cultivated Dolly, a cloned sheep, and Dolly, a cloned monkey. Scientists in China have gradually cultivated cloned cattle, cloned rabbits, cloned pigs and the latest cloned cats.

　　Wonderful cloning technology has shown broad application prospects, such as cultivating excellent livestock and producing experimental animals, producing transgenic animals, producing human embryonic stem cells for cell and tissue replacement therapy, replicating endangered animal species, preserving and spreading animal species resources, and maintaining ecological balance.

　　Four surrogate mothers gave birth to a cloned cat.

　　On January 9 this year, Huang Yu, the owner of the deceased pet cat, formally proposed to Beijing Xinuogu Biotechnology Co., Ltd. to clone "garlic" because he missed it too much.

　　After exploring the pre-experiments such as in vitro maturation culture conditions and parthenogenetic activation conditions of oocytes, the research and development experiment of cloned cats was officially started in August 2018, with a total of 152 experiments. Up to now, one surrogate cat has been successfully delivered, and one surrogate cat has been tested for pregnancy and delivery. In the "Garlic" project, a total of 4 surrogate cats were embryo-transferred. Among them, the surrogate cat CNTR258 was born naturally on July 21st, 2019, 66 days after embryo transfer, and the cloned cat Garlic was successfully produced. Garlic is a very cute British short-haired cat.

　　"Like the general principle of cloned sheep and cloned pigs, we knock out and enucleate the genes of surrogate cats after obtaining the oocytes of surrogate cats, and then implant the cells of cloned cats to form a fused cloned embryo for activation." Wang yining, deputy general manager of Beijing xinuogu biotechnology co., ltd, introduced the birth process of cloned cat "garlic".

　　"Judging from the current level of cloning technology, from the pregnancy of four surrogate cats, a cloned cat was successfully produced, and the success rate was high." Chen Dayuan, a researcher at the Institute of Zoology, Chinese Academy of Sciences, believes. Li Rongfeng also said that as a new cloned species, the pregnancy rate of 25% is very high. Take the cloned pigs of Jiangsu Provincial Key Laboratory of Heterogeneity Transplantation as an example. At present, one to three transgenic cloned pigs can be obtained after transplanting 100 embryos, and the cloning efficiency is about 3%.

　　Shi Zhensheng, a professor at the College of Animal Medicine of China Agricultural University, said: "The reproductive physiological characteristics of cats are different from those of most animals, because cats are not spontaneous ovulation animals, but one of the few ovulation-inducing animals. Their reproductive cycle is special, and cloning technology is difficult and complicated to operate. This successful breeding of cloned cats is one of the few successful cases in the world, marking a big step for China in the field of cloning. "

　　"For the public, spending 250,000 yuan to clone a cat may not be understandable. But I was very happy when I knew that the cloning price was 250,000 yuan. " Huang Yu, the owner of "Garlic", said that he had searched online, and there was a cloning company in South Korea that cloned cats and dogs at a price of 400,000 to 500,000, which was unacceptable. The domestic cloned cat price of 250,000 yuan is acceptable.

　　It can provide reference for cloning pandas.

　　On August 21st, the cloned cat "Garlic" was full moon. From the photos of garlic published on the Internet, we can find that there is a slight difference between the cloned garlic and the original garlic: there is a small black piece on the chin of the original garlic, but the cloned cat is gone; There are patterns on the left leg of the body, and the pattern of cloned cats grows on the right leg.

　　"There are epigenetic problems in the process of animal cloning. The so-called epigenetic problem is that environmental factors will lead to different gene expressions in organisms, but the genes themselves will not change." Li Rongfeng explained that the genes in the cloned cat’s gene nucleus are the same as the original genes from the cat’s cells, but there will be differences in gene expression during the reprogramming of somatic cells. The genes are inherited from the previous cats, but some genes are not expressed or over-expressed; In the cloned cat "garlic", there is a phenomenon that the coat color related genes are not expressed correctly.

　　Beijing Xinuogu Biotechnology Co., Ltd. also responded: "Cloning ensures that more than 99.9% genes are the same, but the hair gene expression is random. There are patterns on the body, and there is no guarantee of 100% consistency. " At the same time, Beijing Xinuogu Biotechnology Co., Ltd. also pointed out that cloned cats can not guarantee the same living conditions and feeding environment as ontologies, and their personalities may change.

　　So what changes may occur in personality? Li Rongfeng said that there are many acquired factors in the formation of cloned cats’ personalities, just as human twins will have different personalities in different environments; But there are some basic personality-determining genes. If they exist in the nucleus, their personality will not change greatly even if the environment is different.

　　What is the significance of the birth of the cloned cat "Garlic"? Li Rongfeng said that from the economic point of view, it is not as important as meat animals, but it caters to the emotional needs of some people, such as pet owners; It is also of great significance to be able to play a companion role.

　　"There is also a great significance in cloning cats, which are closer to giant pandas than pigs and dogs." Li Rongfeng said that the giant panda is a rare and endangered species and it is difficult to clone. The success of cloning cats can provide reference for the cloning of rare and endangered species such as giant pandas.

　　Reporter Zhang Xuan