At the same time, it is essential to consider repair methods that will be able to cope with the most severe damage that might actually occur in practice.
No comments from Merkle. Chemistry can be Critique darticle scientifique at 0 Kelvin. The next problem is how Critique darticle scientifique obtain the necessary information.
Can it be supplied on wires small enough to thread through capillaries without warming the tissue through resistive or frictional heating? Radicals and Pressure Dr. Solving these problems seems to be not just a matter of engineering, but also of creating an entirely new branch of chemistry or materials sciencei.
This is not just a detail to be left to future designers: This might be called "full stabilization. This technical simplicity is gained by relaxing the philosophical criteria, which is a tradeoff that some will not wish to make.
Extruded lipids and proteins cannot be reinserted into the membrane until the cell volume is once again increased because there is no room for them. This might be called "minimal stabilization.
Despite my opinions, some quite intelligent people take the opposite view. An interesting question is the degree of general acceptance of minimally stabilized chemical synthesis.
As an aside, frozen synthesis would allow the cryoprotectant concentration and even the type of cryoprotectant to be varied from tissue to tissue or even cell to cell to achieve optimal tissue-specific cryoprotectant concentrations.
Although he says that temperature of repair is left open, he clearly favors repair at temperatures below the glass transition temperature, e. The revised structural data base clearly specifies such an object the brain and specifies its structure in precise molecular detail.
This seems to leave the "slamming" approach as the main possibility. Consider that image analysis systems with good resolution store individual images at megabytes or more per 2-D frame, exclusive of any analysis of the image.
And this is the Critique darticle scientifique that cryobiologists have had with cryonics all along. Finally, tissue will be brittle below Tg and may be brittle even at temperatures moderately above this. Of course, we can also apply high pressure.
At body temperature, nanomachines could be powered by chemical energy the way metabolism is powered. Assuming that the two time scales are even in the same ballpark amounts to pure handwaving.
By both minimizing freezing damage and maximizing repair capabilities we will achieve the highest possible probability of success. Analysis of the fundamental speed limits produces numbers that are shockingly good and were not needed to support the basic case. In simple organisms the growth of every single cell and of every single synapse is determined genetically.
Any denatured proteins will also prefer to be denatured under the prevailing conditions. The structure being examined was taken apart. But the "slamming" approach and the "jamming" approach are fundamentally similar, the main difference being the time scale over which energy is applied.
How can energy be translated from the macroscopic to the molecular level? Clearly, given a specific molecule, and given that we are pulling on it hard enough to rupture a bond, one of two things will be true. Critique darticle scientifique, without more detailed calculations which, as indicated above, may be impossiblethe biological time scales and the nanotechnological repair time scales assuming that nanotechnological repair is possible at C in the first place cannot be related to one another.
The fairly long sections of the paper looking at projected future memory and computational capacities were intended specifically to address that issue. While questions about the fundamental physical limits of computation have attracted a great deal of interest for rather obvious economic reasonsno one has yet to my knowledge published a paper discussing the fundamental physical limits to the speed of synthesis of a complex object.
Much as the rapid heating proposal is charming, a proposal of Dr. It seeks only to describe peripheral issues of information content, computational speed, etc. An issue which I view as completely irrelevant, but which causes some people concern, is the retention of the "original" atoms.
Such an attempt, if successful, should send doubting cryobiologists packing and make the world safe for cryonics forever. Thus, repair would restore the original person with the original cellular structure and the original molecules, but the molecules would have been allowed to diffuse within their cellular compartments or diffuse two-dimensionally within a membrane much as they would normally do.
The importance of this paper lies in its attempt to demonstrate the likely feasibility of cryonics through a series of logical and mathematical arguments. I assume the cracks are "clean" low temperature fractures. Merkle does not really address the issue of determining WHERE molecules ought to be and carrying out the actual procedure of repositioning them.
The following taxonomy is not intended to be exhaustive, but is intended to provide the reader with a feeling for the range of possibilities available.Critique de l’article; Il s’agit d’un article scientifique du domaine de la neuropsychiatrie.
Comme tout article scientifique il se doit de répondre à une question ou de résoudre un problème. Nous verrons dans cette critique dans quelle mesure il s’y applique/5(1).
On ne article scientifique peut en effet en aucun cas se limiter & la lecture des r&urn& pour se faire une idle fiable sur une ques- tion. 11 faut toujours avoir un ceil critique sur les donn&es qui ont permis de tirer des conclusions.
Notez que tout article cité dans un document scientifique doit avoir été lu. Quand on dit lu, ça veut dire qu’il faut que vous ayez vérifié que l’article dit bien ce que vous avancez. II — Les principes de la communication médicale scientifique.
III — La structure du rapport d'une étude. IV — Les principes de la lecture critique. V — La lecture critique Pages: Nov 17, · Les principaux critères à retenir pour l'identification d'un article de revue scientifique sont présentés dans cette vidéo.
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