Self repair

Aluminide and sUicide cementation coatings such as TaAl on tantalum and MoSi2 on molybdenum oxidize at slow rates and possess some inherent self-repair characteristics. Fine cracks that appear and are common to these coatings can be tolerated because stable, protective oxides form within the cracks and seal them. Thermal cycling, however, accelerates faUure because of thermal expansion mismatch that ultimately dismpts the protective oxide coating. 

Lead and Alloys Chemical leads of 99.9+ percent purity are used primarily in the chemical industiy in environments that form thin, insoluble, and self-repairable protective films, for example, salts such as sulfates, carbonates, or phosphates. More soluble films such as nitrates, acetates, or chlorides offer little protection. 

There are many grades of stainless steel, and some are virtually non-corrodible under ordinary atmospheric conditions. Their resistance results from the protective and normally self-repairing oxide film formed on the surface. However, under reducing conditions, or under conditions that prevent the access of oxygen, this film is not repaired, with consequent corrosion. 

Historically, the first capacitors using an electrocfiemical system were the electrolytic capacitors. Built like film capacitors, they have electrodes made of aluminum foil on which by electrochemical oxidation a thin film of aluminum oxide (i.e., 10 to lOOnm thick) is grown to serve as the dielectric. Solutions are used as the electrolyte which aid self-repair of the oxide film on aluminum after accidental damage. Such electrolytes are solutions of salts of a number of orgaiuc acids (trifluoroacetic, salicylic, and some others). Because of the small thickness of the oxide layer, electrolytic capacitors have a markedly higher capacity than film capacitors. They can thus be used in the microfarad range. 

Gregory, and it still applies - if you take a radio and delete a transistor from it and the result is that instead of a symphony you get a howl, you can t conclude that the function of the transistor was a howl suppressor. That is one of the major problems of knock-out studies, that they are compounded by the fact that if you take a transistor out of a radio it can t self-repair. In a developing animal, if you take out a gene, then what you get is compensatory plasticity, other processes taking over as well. So the interpretation of any of those knock-out studies is immensely complicated. 

Fault-tolerance capability and even self-repair ability of the molecular circuit... 

Such effects are likely to be important. The use of SP interactions to create bioinspired material properties (e.g., see Chap. 9) implies that the ultimate yield behavior of SP materials could depend on the mechanical response of supramolecular interactions. Paulusse and Sijbesma (2004) have also shown that ultrasound-generated shear stresses can mechanically tear apart coordination SPs, damage that is subsequently repaired during dynamic equilibration once the shear stresses are removed. The mechanical response of supramolecular interactions within materials has potentially important consequences in the context of self-repairing materials, where the mpture of sacrificial supramolecular interactions protects a permanent, underlying materials architecture. The dynamic repair of the SP component in... 

Kersey FR, Loveless DM, Craig SL. A hybrid polymer gel with controlled rates of cross-link rupture and self-repair. J R Soc Interface 2007 4 373-380. 

Liu Y-L, Chen Y-W. Thermally reversible cross-linked polyamides with high toughness and self-repairing ability from maleimide- and furan-functionalized aromatic polyamides. Macromol Chem Phys 2007 208 224-232. 

Kempermann, G., van Praag H., and Gage, F.H. (2000) Activity-dependent regulation of neuronal plasticity and self repair. Prog Brain Res 127 35—48. 

Thanks to the outside supply of substrates, such a cell should be capable of selfmaintenance and of self-reproduction, including replication of the membrane s components. However it would not make low-molecular-weight compounds and would not have redundancies for its own defense and security - all self-repair mechanisms are missing. Also, there is the problem of leakage and lack of concentration gradients and cell division would be simply due to a physically based statistical process. 

Man-made materials which can, to different degrees, self assemble, self diagnose, self repair, and recognize and discriminate physical and/or chemical stimuli, and, at the extreme, which have the capability of learning and self replicating The term is often considered to be synonymous with intelligent materials . 

Volume I, Adult Neurogenesis and Neural Stem Cells, provides an overview and in-depth analysis of the new field of stem cell research that is the generation of new neuronal cells and the existence of stem cells, in the adult brain of mammals. These discoveries have forced us to re-think and re-evaluate how the brain is functioning, and reveal that the adult brain has the potential for self-repair. This volume covers the basic science of adult neurogenesis and neural stem cell research, from the origin, mechanisms, function, and the therapeutic potential of adult NSCs. 

Even when methyl radicals are replaced by silanol units, the surface of the material does not remain hydrophilic (water-wettable) very long. Either the silanol groups condense with other silanol units to restore the siloxane structure, or unmodified chain segments migrate to the surface. In any case, a self-repair mechanisms underlies the recoverability of siloxane surfaces, and this is an important part of their durability. 

The opposite direction of transfer is also perfectly exploitable if required by the designer. Such PET processes are of course responsible for green plant photosynthesis [32-36], In the present simple instance the electron transfer is essentially reversed immediately following excitation. Such self-repair is essential following a potentially lethal PET process so that the molecular system is reasonably photostable. The important net result for us is that no luminescence is seen following excitation. This is the off state of the molecular switch. 

Shchukin DG Mohwald H, Self-repairing coatings containing active nanoreservoirs, Small, 2007, 3,... 

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