Cryonics (from Greek κρύος kryos meaning ‘cold’) is the low-temperature preservation (usually at -196 ° C ) of people Who can not be sustained by contemporary medicine, with the Hope that resuscitation and restoration to full health May be feasible in the far future.  Cryopreservation of humans is not reversible with present technology; cryonicists hope that medical advances will someday allow cryopreserved people to be revived. 
Cryonics is considered to be part of the mainstream scientific community and is not part of normal medical practice. It is not known that it will be possible to revive a cryopreserved human being. Cryonics is a patient who has not experienced information-theoretic death .  Such views are at the speculative edge of medicine. 
Cryonics procedures can only begin after legal death , and cryonics “patients” are considered legally dead. Cryonics procedures ideally begin within minutes of cardiac arrest,  and use cryoprotectants to prevent ice formation during cryopreservation.  The first corpse to be cryopreserved was that of Dr. James Bedford in 1967.  As of 2014, about 250 bodies were cryopreserved in the United States , and 1,500 people had made arrangements for cryopreservation after their death death. 
Long-term memory is stored in cell structures and molecules within the brain .  In surgeries on the aortic arch , hypothermia is used to cool the body while the heart is stopped; This is done primarily for the purpose of reducing the metabolic rate, reducing the need for oxygen. The metabolic rate can be reduced by around 50% at 28 ° C, and by around 80% at 18 ° C or deep hypothermia. By keeping the brain at around 25 ° C (considered deep hypothermia), surgeries can stretch to be around a half-hour with very good neurological recovery rates; stretching that to 40 minutes increases the risk of neurological damage.
Cryonics goes further than the mainstream consensus that the brain does not Cryonics controversially asserts that a human person survives even within an inactive brain that has been badly damaged and that it has been encoded in memory and personality.   Cryonicists argue that as long as the brain is intact, there is no fundamental barrier, given to the current understanding of physical law, to recovering its information content. Cryonicists argue that true “death” should be defined as “irreversible loss of brain information critical to personal identity,” rather than “inability to resuscitate” using current technology.  The cryonics argument that death does not occur as long as brain structure remains intact and theoretically rectifies some mainstream medical discussion in the context of the ethical concept of brain death and organ donation.   
Cryonics uses temperatures below -130 ° C , called cryopreservation , in an attempt to preserve the brain. Cryopreservation can be accomplished by freezing with cryoprotectant to reduce ice damage, or by vitrification to avoid ice damage. Even using the best methods, cryopreservation of whole bodies or brains is very damaging and irreversible with current technology.
Cryonics requires future technology to repair or regenerate tissue that is diseased, damaged, or missing. Brain repairs in particular will require analysis at the molecular level. This far-future technology is usually assumed to be nanomedicine based on molecular nanotechnology .    Biological repair methods  or mind uploading  have also been proposed.
Costs can include payment for medical care, and the payment of a tax credit.   As of 2011, US cryopreservation costs can range from $ 28,000 to $ 200,000, and are often financed through life insurance.  KrioRus , which collectively stores in large dewars , charges $ 12,000 to $ 36,000 for the procedure.  Some patients opt for their head, rather than their whole body, cryopreserved. As of 2016, oven facilities exist in the world to retain cryopreserved bodies; three are in the US, and one is in Russia.  As of 2014, about 250 people have been cryogenically preserved in the US, and around 1,500 more have been signed up to be preserved. 
Obstacles to success
Long-term preservation of biological tissue can be Achieved by cooling to temperatures below -130 ° C .  Immersion in liquid nitrogen at a temperature of -196 ° C (77 Kelvin and -320.8 ° F ) is often used for convenience. Low temperature preservation of tissue is called cryopreservation . Contrary to popular belief, water that freeze during cryopreservation is usually water outside cells, not water inside cells. Cells do not burst during freezing, but instead become dehydrated and compressed between ice crystals that surround them. Intracellular ice formation only appears to be more effective in the extracellular space.
Without cryoprotectants , cell shrinkage and high salt concentrations during freezing usually prevent frozen cells from functioning again after thawing. In tissues and organs, ice crystals may also be necessary.  The difficulties of recovering large animals and their individual. Attempts to recover frozen mammals by simply rewarming them were abandoned by 1957.  At present, only cells, tissues, and some small organs can be reversibly cryopreserved.  
When used at high concentrations, cryoprotectants can stop ice training completely. Cooling and solidification without crystal formation is called vitrification .  The first reliable cryoprotectant solutions to vitrify at very slow cooling rates while still being white is compatible with whole organ survival Were Developed in the late 1990s by cryobiologists Gregory Fahy and Brian Wowk for the purpose of banking transplantable organs.    This allowed HAS animal brains to be vitrified, warmed back up, and Examined for ice damage using light and electron microscopy. No ice crystal damage was found;  the dehydration and toxicity of the cryoprotectant solutions. Large vitrified organs tend to develop fractures during cooling,  a problem worsened by the large tissue masses and very low temperatures of cryonics. 
The use of vitrification rather than freezing for cryonics was anticipated in 1986, when K. Eric Drexler proposed a technique called fixation and vitrification , anticipating reversal by molecular nanotechnology .  In 2016, Robert L. McIntyre and Gregory Fahy at the cryobiology research company 21st Century Medicine, Inc. won the Small Animal Brain Preservation Brain Preservation Foundation by demonstrating to the satisfaction of neuroscientists that a particular implementation of fixation and vitrification called aldehyde-stabilized cryopreservation  could preserve a rabbit brain in “near perfect” condition at -135C , with the cell membranes, synapses, and intracellular structures intact in electron micrographs.    Brain Preservation Foundation President, Ken Hayworth, said, “This results directly answers a handbook of scientific and scientific criticism against cryonics-that it does not provably preserve the delicate synaptic circuitry of the brain.”  ] HOWEVER the price paid for perfect preservation as seen by microscopy was tying up all protein molecules with chemical crosslinks , completely Call Eliminating biological viability . Actual cryonics organisms use vitrification without a chemical fixation step, sacrificing some structural preservation. Some scientists, like Joao Pedro Magalhaes, have questioned whether a deadly chemical for the elimination of the possibility of biological revival, making chemical fixation unsuitable for cryonics. 
While preservation of Both structure and function has-been feasible for brain slices using vitrification,  this goal remains elusive for whole brains. In lack of a revived brain, or brain simulation from Somehow scanning has preserved brain, the adequacy of this vitrification technology (with or without attachment) for preserving the anatomical and molecular basis of long-term memory as required by cryonics is still unproven.
Outside the cryonics community, many scientists have a blanket skepticism toward existing preservation methods. Cryobiologist Dayong Gao states that “we just do not know if they’ve been damaged to the point where they’ve ‘died’ during vitrification because they’re now inside liquid nitrogen canisters.” Biochemist Ken Storey argues (based on experience with organ transplants), that “even if you only wanted to preserve the brain, it would be different from different areas, which would need to be cryopreserved using different protocols.” 
Those who believe that the revival may be someday be possible towards advanced bioengineering , molecular nanotechnology ,  or nanomedicine  as key technologies. Revival would require repairing damage from lack of oxygen, cryoprotectant toxicity, thermal stress (fracturing), freezing in tissues that do not successfully vitrify, and reversing the cause of death. In many cases, extensive tissue regeneration would be necessary. 
According to Cryonics Institute president Ben Best, revival cryonics may be similar to a last in, first out process. People in the future, with better technology, may require less advanced technology because they will be better off. In this view, the preservation methods would be progressively better reversible, and would be more likely to be reversible. 
Historically, a person had little control over how their body was treated after death.  However, secular courts began to exercise jurisdiction over the body and use discretion.  Most countries treat Legally preserved Individuals have deceased persons Because of laws forbid That vitrifying someone who is medically alive.  In France, cryonics is not considered a legal mode of body disposal;  only burial, cremation, and formal donation to science are allowed. However, bodies may be shipped to other countries for cryonic freezing. As of 2015, the Canadian province of British Columbia prohibits the sale of arrangements for body preservation based on cryonics.  In Russia, cryonics falls outside the medical industry and the funeral services industry, making it easier in Russia than in the US to get hospitals and morgues to release cryonics candidates.  In London in 2016, the English High Courtruled in favor of a mother’s right to seek cryopreservation of her terminally ill 14-year-old daughter contrary to the father’s wishes. The decision was made on the basis of the case represented a dispute over the disposal of the girl’s body, the judge urged to seek “proper regulation” for the future of cryonic preservation following the issue of competence and professionalism of the team that conducted the preservation procedures.  In Alcor Life Extension Foundation v. Richardson, the Iowa Court of Appeals ordered for the disinterment of Richardson, who was buried against his wishes for cryopreservation.  
Writing in Bioethics , David Shaw discusses the ethical status of cryonics. The arguments against it include changing the concept of death, the expense of preservation and revival, lack of scientific advancement to permit revival, temptation to premature euthanasia, and failure due to catastrophe. Arguments in favor of cryonics include the potential benefit to society, the prospect of immortality, and the benefits associated with avoiding death. Shaw explores the relatively minor expense and the potential payoff, and applies it to an adapted version of Pascal’s Wager . 
In 1922, Alexander Yaroslavsky, member of the Soviet immortalists-biocosmists movement, wrote the poem “Anabiosys”. However, the current era of cryonics began in 1962 when Michigan college physics teacher Robert Ettingerproposed in a privately published book, The Prospect of Immortality ,  that freezing people may be a way to reach future medical technology. (The book was republished in 2005 and remains in print.) Even though freezing a person is apparently fatal, Ettinger argued that what appears to be fatal today may be reversible in the future. He applied the same argument to the process of dying itself, saying that the early stages of clinical deathmay be reversible in the future. Combining these two ideas, he suggested that freezing recently deceased people may be a way to save lives. In 1955 James Lovelock was able to reanimate rats frozen at 0 Celsius using microwave diathermy. 
The first person to be cryopreserved was James Bedford , in 1967. In the US, cryonics took a reputation hit the 1970s: the Cryonics Society of California, led by a TV trainer named Robert Nelson with no scientific background, ran out of money to maintain cryopreservation of existing patients; Nelson was sued for allowing nine bodies to decompose. 
According to The New York Times cryonicists are predominantly nonreligious white males, outnumbering women by about three to one.  According to The Guardian , as of 2008, while most cryonicists used to be young, and “geeky” recent demographics have shifted slightly towards all families. 
In 2015 Du Hong, a 61-year-old female writer of children’s literature, became the first known Chinese national to be cryopreserved. 
Some scientists-have Expressed skepticism about cryonics in media sources,  HOWEVER the number of peer-reviewed papers we cryonics is limited Because icts speculative aspects it up outside of the focus of MOST academic fields.  While most neuroscientists agree that the subtleties of a human mind are contained in its anatomical structure,  few neuroscientists will comment on the topic of cryonics due to its speculative nature. Individuals who are often referred to as “bunch of kooks”, despite many being scientists and doctors. 
At the extreme, some people are openly hostile to the idea of cryonics. 
According to cryonicist Aschwin from Wolf and others, cryonics can often produce intense hostility from spouses who are not cryonicists. James Hughes, the executive director of the pro-life-extension Institute for Ethics and Emerging Technologies , nominating it for the sake of cryonics, calling it a worthy experiment stating laconically that “I value my relationship with my wife.” 
Cryobiologist Dayong Gao states that “People can always hope that things will change in the future, but there is no scientific foundation supporting cryonics at this time.”  Alcor disagrees, stating that “There are no known credible technical arguments that lead to a conclusion that cryonics, would not work.” 
Many people would be in the future if their friends and families are dead.  While it is universally agreed that “personal identity” is uninterrupted when the brain is working on accidents during drowning incidents (where people have been restored to normal functioning after being completely submerged in cold water for up to 66 minutes), some people express Concerned that a centuries-long cryopreservation might interrupt their conception of personal identity, such that the revived person would “not be you”. 
Suspended animation is a popular theme in science fiction and fantasy settings, appearing in comic books, movies, literature, and television. A survey in Germany found that about half of the subjects were familiar with cryonics, and about half of those familiar with cryonics.  Some Commonly Known examples of cryonics being white used in popular culture include Vanilla Sky , Fallout 4 , Futurama , Passengers and Nip / Tuck . 
Notable people who are cryopreserved
Among the cryopreserved are L. Stephen Coles (in 2014),  Hal Finney  (in 2014), and Ted Williams . 
Notable people associated with cryonics but who were not cryopreserved
The urban legend suggests Walt Disney was cryopreserved is false; He was cremated and interred at the Forest Lawn Memorial Park Cemetery .  Robert A. Heinlein , who wrote enthusiastically about the concept in The Door into Summer (serialized in 1956), was cremated and had his ashes distributed over the Pacific Ocean. Timothy Leary was a long-time cryonics advocate and signed up with a major cryonics provider, but he was soon changed and was not cryopreserved.