Chapter 820

In the staircase classroom, Lu Weiwei's performance is really dazzling.

As everyone knows, Lu Weiwei, like officer Wang, is from the criminal investigation team of Furong Branch of Jiangnan City.

For forensic medicine, both of them belong to laymen, but the instructor Zhang Hui's question is not difficult to them.

This makes many forensic doctors who want to see jokes feel disappointed.

Zhang Hui was stunned, and then calmed down from his surprised eyes: "very Very well. Please have a seat

Lu Weiwei nodded, sat down and blinked her right eye at Gu Chen.

But suddenly there was a whisper.

"The police in Furong Branch of Jiangnan City are really good."

"Yes, two consecutive questions have been blurted out. It can be seen that people's knowledge reserves are not as much as usual."

"Shit, are all Xueba sent by Jiangnan City this time? No wonder they came to the training. "

……

Also see people bow their heads whisper, bareheaded instructor Zhang Hui cough twice, the scene just gradually quiet down.

"This female student just said very well. Yes, these characteristics make diatoms widely used in red tide detection, aquaculture, water quality monitoring, resource investigation, paleoenvironmental analysis, petroleum exploration, forensic identification and other fields."

"Moreover, diatoms belong to the diatoms of Bacillariophyta. Diatoms are phytoplankton. Diatoms can be found in almost all places on the earth where there is water retention, from small puddles formed by rainwater accumulation to as large as 71% of the earth's surface ocean."

"There are also diatoms that grow as terrestrial types on moist soil surfaces and exposed surfaces of other objects, and some float in the air."

Looking up at Gu Chen's direction, Zhang Hui finds that officer Wang and Lu Weiwei are clapping hands with Gu Chen.

Suddenly that relaxed brow again tight.

Zhang Hui coughed twice and said absently: "we all know that there are more than 16000 kinds of diatoms in the world, with body length of 1-200 μ M. diatoms are sensitive to water quality. Different water environments lead to different diatom communities."

"The most obvious feature is that the cell wall is highly silicified except for some species, forming two transparent shells, the top and the bottom, and a siliceous cell wall formed by the shell ring band. It is hard and stable, not easy to be damaged, and not affected by corruption and death."

"Even if concentrated sulfuric acid and nitric acid are boiled, it is difficult to destroy their texture features, so based on these characteristics, diatoms play a significant role in forensic detection."

Ppt pictures quickly turn to the next stage of blue copy.

Zhang Hui suddenly stood up and went to the whiteboard on the platform and wrote some copy materials on the whiteboard.

Looking back at the crowd, Zhang Hui hit the white board with the back of his hand and drew the key points.

"All of you have paid attention to this point. We all remember that because of the active breathing of the water users before birth, diatoms can be inhaled into the alveoli with the drowning fluid, enter the blood circulation, and distribute to various tissues and organs."

"Moreover, qualitative and quantitative analysis and comparison of diatoms in organs and water can not only directly determine the cause of death, but also help to infer the place of drowning."

When the medical students heard the speech, they all copied it into the record.

We may all know this, but it is the first time for many people to understand the characteristics of diatom.

Therefore, no matter who knows or doesn't know, we all bow down to take notes.

The scene painting style is very harmonious, but only Gu Chen in the back corner is still unmoved.

But it's not that Gu Chen is unwilling to take notes. It's just that Gu Chen has read the information in the municipal library a few months ago.

Instructor Zhang Huigang just said these contents, Gu Chen has already used the specialized level memory, the perfect record in the mind.

Wang and Lu Weiwei's answer just now is the best embodiment of their own verification of memory.

Zhang Hui felt that Gu Chen didn't give face.

From the beginning to the present, Gu Chen almost does not write, which is a very different kind of existence in the dogmatic training system.

Zhang Hui frowned and continued, "let's talk about a long-standing problem, that is, the identification of the cause of death in water."

Looking at Gu Chen's indifferent face, Zhang Hui chuckled: "I need a teaching assistant to help me write the whiteboard. I don't know Which student is willing to? "

The scene was quiet for a few seconds, and several students in the front row raised their right hands one after another.

However, after pretending to observe, Zhang Hui suddenly pointed to Gu Chen and said, "just The student, yes, you are the one sitting in the last row beside the female student who answered the question just now

"Me?" Gu Chen was suddenly called, but also directly stood up to confirm.

"Yes, you are." Instructor Zhang Hui reconfirmed.

Gu Chen walked out of his seat and walked down the stairs to the platform.

Zhang Hui handed the oily pen to Gu Chen and said with a smile, "this student, you can stand here and help me write the whiteboard."

"No problem." Gu Chen nodded slightly, took the oil pen, and went directly to the whiteboard.Zhang Hui took a long sigh of relief. He said that if the little Comrade stood on the platform and listened to his lecture, he should be able to concentrate his attention?

It's good for him to think about it

So Zhang Hui returned to his seat and continued to lecture.

"We just talked about a big problem, that is, the identification of the cause of death in water."

"Dudu Dudu..."

As soon as Zhang Hui's voice dropped, Gu Chen had already written the six characters "identification of the cause of death of the corpse" on the top of the whiteboard.

* Zhang Hui stole a glance at it, and was satisfied. He continued, "we all know that drowning is a form of death due to fluid blocking respiratory tract and alveoli, blocking gas exchange, hypoxia in the body, carbon dioxide retention, and thus suffocating."

As the voice dropped, Gu Chen had listed several key points, almost synchronized.

Zhang Hui didn't care, but went on to say: "according to the 2004 World Health Organization's global drowning report, 342000 people drown in the world every year, with an average of 42 deaths per hour."

"According to statistics, there are also about 60000 people drowning every year in China. Drowning is the third cause of accidental death in China and the first cause of death among children under 14 years old."

After seeing himself finish, Gu Chen suddenly stops writing.

Zhang Hui glanced at him and reminded him, "write it up."

"Drillmaster, your data don't seem to be very accurate." Gu Chen did not mean to continue, but questioned Zhang Hui.

The scene suddenly became lively

Everyone didn't expect that Gu Chen would question the data of instructor Zhang Hui face to face. In our opinion, is Gu Chen too floating?

For a moment, people were talking about it.

Seeing this, Zhang Hui asked Gu Chen, "what's your name, this student?"

"Gu Chen." Gu Chen said.

"Which unit are you from?" Zhang Hui asked again.

"The third criminal investigation group of Furong Branch of Jiangnan City." Gu Chen said.

Zhang Hui immediately hums a smile, way: "I say Gu Chen, I have read your file, you should not be a forensic doctor?"

Gu Chen nods.

"So how do you question my data?" Zhang Hui asked again.

Instead of saying anything, Gu Chen changed the global drowning report released by the World Health Organization in 2004 to 2014.

Subsequently, the data of 342000 people drowning in the world every year was revised to 372000.

Zhang Hui suddenly froze, he quickly looked down at the information in his hand, but suddenly surprised.

Gu Chen's modified data is no problem. Instead, it is a data error in the information on hand.

Indeed, the statistical report comes from 2014, but it is 2004, which is 10 years different.

However, in 2014, the number of drowning people was 372000, but the data on hand was 342000, a difference of 30000.

Zhang Hui was a little surprised

"How did Gu Chen know? Can he even know that my data is wrong? Isn't it amazing? "

Zhang Hui's heart a burst of panic, but picked up the information in his hand, fingerprint assistant Yang Ting said: "sample, this information is your collation, right?"

"Yes." Yang Ting nodded silently: "it is sorted out according to your manuscript."

"Look at you, carelessness." Zhang Hui threw the A4 paper data on the table, but he didn't have a good way: "you typed these data wrong."

"Hit Big mistake? " Yang Ting heard the speech, but also quickly self-examination: "won't it? How could it be a big mistake? "

Zhang Hui picked up the manuscript, tapped his fingers and said, "it is clearly written on my manuscript that according to the 2014 World Health Organization's global drowning report, 372000 people drown every year in the world, with an average of 42 deaths per hour."

"And you see what you've done? 2014 has become 2004, 372000 people have become 342000 people, you are too careless

"Is it?" Yang Ting was a little flustered.

She quickly from the file bag, Zhang Hui will give her to take out the manuscript, open a few pages for verification.

After a moment, Yang Ting's whole person was dumbfounded: "it's really wrong."

Glancing at Zhang Hui, Yang Ting also bowed her head to apologize and said: "sorry, it may be typing too fast, did not verify clearly, really sorry."

"Well, pay attention next time." Zhang Hui also waved his hand to let Yang Ting sit down first, and then said:

"our work must be rigorous. This time, it is just a report. If there is a data error in the laboratory operation stage next time, it is not generally serious. It is very likely that the results of our efforts will be paid to the East."

"Yes, yes, my pot." Yang Ting is also brave enough to take on the mistakes, but she doesn't quite understand: "but How does Gu Chen know that my data is wrong? I didn't show him the manuscript either? ""Yes, how did Gu Chen know that?"

There are many people who have doubts about the scene and Yang ting.

You know all this data? The heart says you ya should not even have recited Xinhua dictionary?

Zhang Hui is also stupefied, just now Yang Ting's question, but let himself feel confused.

Gu Chen was able to find the problem at the first time when his data was wrong.

More importantly, he can accurately express the real statistical data, which shows that Gu Chen also has some understanding of this report.

Zhang Hui looked up and down at Gu Chen, and then asked him, "Gu Chen, how do you know?"

"I read the WHO Global drowning report in 2014." Gu Chen said.

"Have you seen it?" Zhang Hui doubted and continued to ask him, "have you even contacted this one?"

"I read it in our Jiangnan library a few months ago." Gu Chen said.

Zhang Hui pinched his chin, but he could not set the channel: "but It's been a few months, and you can remember the data now? "

"Yes, but I still remember who estimates that the actual number could be twice as high."

"Well said." Seeing that Gu Chen can accurately tell these data, Zhang Hui's eyes have changed.

I feel that this young man has excellent memory and is far better than others.

After a burst of sweat, Zhang Hui picked up the writing pen on the desk and corrected the data. Then he said again:

"after all, due to the dense network of rivers and lakes in China, the number of drowning dead bodies that need to be identified every year is huge."

"The vast majority of drowning bodies found in rivers, lakes and seas are accidental deaths of drowning people. However, some drowning bodies have committed suicide or homicide, and it is not ruled out that throwing corpses into the water after death can be forged as accidental drowning deaths."

Zhang Hui glanced at Yang Ting, who immediately switched slides.

At this moment, the screen shows a picture of a city river.

One side of the city's River is cordoned off, while on the other side is a blue tent temporarily set up by the police.

Zhang Hui coughed twice and continued: "drowning deaths have occurred from time to time over the years, but detection is also very difficult."

"It's OK to have witnesses who can determine the cause of death, but for those drowning without witnesses, detection techniques are needed."

"and for fresh water corpses, drowning can be identified by typical signs of drowning, such as oral and nasal mushroom foam, water emphysema, and sediment in the respiratory tract."

"However, when more than 80% of the bodies in the water are found, they are highly corrupt, and the signs of drowning are no longer present."

"Moreover, autopsy and histological examination, whether there are specific pathological changes related to drowning, the cause of death identification has become a worldwide recognized problem, and the cause of death is the key to determine the nature of the case."

After a pause, Zhang Hui saw that Gu Chen had written down the main points, but he could not help saying, "this involves the handling work of the police."

"Because the cause of death is unknown, the case can not be determined, which easily leads to dissatisfaction of family members, public opinion speculation and media speculation."

"Therefore, our forensic medicine must accurately detect, find out the cause of death of the deceased, and give a satisfactory account to the family members, otherwise it will cause great trouble."

Seeing Gu Chen's tacit understanding on the whiteboard, Zhang Hui's attitude improved a lot. He asked Gu Chen casually, "Gu Chen, do you know any famous examples?"

Gu Chen stopped writing and thought about it carefully. Then he said, "the blue Cole incident happened in February 2013 in the United States is a typical example."

"That's right." Zhang Hui nodded slightly and said to the audience: "therefore, if the investigation is not thorough, it will cause a lot of social problems, which requires our rigorous work, so it puts forward higher requirements for our forensic examination."

After looking at Gu Chen, Zhang Hui said again, "Gu Chen, do you know what experiments have been done by our forensic workers in order to solve the problem of identifying the cause of death in water?"

All of a sudden, the scene was quiet, and all of them were sweating for Gu Chen.

Heart says instructor Zhang Hui this is to rely on Gu Chen?

You can't just pick one to collect wool, can you? You don't give the others a chance?

In fact, many forensic doctors know something about it, but Zhang Hui only gives Gu Chen the chance to answer. He also wants to take an entrance examination of this young man's real level.

After a few seconds of contemplation, Gu Chen's data flow in his brain began to roll rapidly and quickly floated into his mind.

Gu Chen raised his head and said: "forensic workers have studied diatom test, blood biochemical test, foreign matter element test, plant pollen spore test, chlorophyll-a test and other methods."

"However, except for diatom detection, other methods are limited to experimental research and have not been widely applied in forensic practice."

"Well said." Zhang Hui was very satisfied with Gu Chen's answer, so he said with a smile, "so diatom test, as I said, is the 'gold standard' for drowning diagnosis.""There are some controversies about how to judge whether to enter water before or after death, but diatom test has always been the most common method in forensic practice."

"But there are also doubts and controversies." Gu Chen rebutted back directly.

Zhang huiwrinkled and frowned, some unhappy, heart said that Gu Chen came to smash the scene?

But Gu Chen said it was right. Zhang Huigang wanted to open his mouth and sat next to another first-class police officer. "Guchen, you said there are also doubts and arguments about diatom detection. Why?"

"Because at present, most forensic doctors at home and abroad are using optical microscopy to detect diatoms in the organs of drowning deaths."

"The diatom test method can not directly determine the exact cause of death of drowning death, but it is helpful to determine the death site of drowning death by comparing the types and quantity of water samples in the drowning place of drowning death

Gu Chen seamless docking, his own views, and then said:

"although diatom test is used in drowning diagnosis, it has been more than 100 years old, but the value of diatom test has been controversial, mainly because of the current world, there are many methods of diatom testing used by legal and medical circles in various countries."

"The main method is to use the method of diatom enrichment and observation of diatom after the sample is extracted and digested," Gu Chen directly picked up the oily pen and wrote on the white board

Looking back at the audience, Gu Chen went up and explained to you, "because diatoms are widely distributed in nature, fresh water, sea water, air and food, especially vegetables, are common."

"In addition, passive pollution of body in water, atypical drowning and entering water after death, and dead bodies in some areas where diatoms are absent, and the pollution problems of the experiment itself, in fact, include many factors such as containers and reagents, which make the diatom test controversial in the diagnosis of drowning. "

when people heard the words, they nodded frequently, which seemed to make sense.

However, Gu Chen's old problems were made. He immediately treated this as the scene of the crime, and explained to the public: "in fact, domestic and foreign diatom testing laboratories have been using the technology of boiling digestion with strong acid, centrifugation and optical microscopy."

"These traditional technologies have obvious defects, which are not only the above pollution problems, but also the following aspects The recovery rate of diatom extracted from organ inspection material is low, the sensitivity of inspection is poor and the false negative rate is high. "

"However, diatom is small in size and low in content, limited by the magnification of light microscope, and it is easy to miss and mischeck."

"Cough." Seeing Gu Chen snatched his right to speak, the instructor Zhang Hui complained and coughed two times to remind him.

But Gu Chen did not pay attention to it, and continued with a loud finger: "diatom test requires species identification of the diatoms detected."

"Forensic inspectors usually lack the expertise of diatom taxonomy and misjudge other foreign body properties as diatoms, which restricts the application of diatom test in drowning diagnosis to some extent."

"OK All right. " Seeing Gu Chen gushing, there is no stop meaning, the instructor Zhang Hui is a little panicked, and quickly interrupts: "guchen, you still sit back."

……

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