Damage accumulation

To describe the damage in stage I, a damage accumulation law is proposed ... 

Systematic cell degradation and death, apoptosis, on the other hand, is thought to be necessary to avoid cell damage accumulating so as to cause incorrect differentiation. The process is very complicated involving activation of a number of destructive enzymes where once more increase in cell calcium often initiates the hydrolyses using special internal calcium-dependent enzymes, calpains (see Demaurex in Further Reading). 

The degradation of composites has been reviewed by Bank and co-workers [1] and in the work at the National Physical Laboratory (see Section 12.11). Apart from the special circumstances of damage accumulation in fatigue, the models are the same as those applying to plastics in general. 

Information on the fatigue, moisture diffusion and damage accumulation in polymer composites is understood to be available in the Delaware Composites Design Encyclopedia [21]. 

Nevertheless, drugs effects can compete with BrdU uptake in DNA synthesis machinery in case of antimetabolites treatments [20] or after lacking ability to incorporate following DNA damages accumulation or in case of presence of apoptotic cells. Moreover, when cells are delayed between Gi to S (early S, ES) or S to G2/M (late S, LS), only DNA content analysis make accurate quantifications impossible [25],... 

In this section we will review the current knowledge of ion damage accumulation and chemical profiles in as-implanted single-crystal SiC. We will investigate the effects of the postimplant annealing process in Section 4.3. Results for the 4H- and 6H-SiC polytypes will also be presented. 

Figure 4.6 shows data that summarize the current knowledge about damage accumulation in SiC versus ion mass and implantation temperature. Almost all the experimental data that will be discussed from here on concerns the Si sublattice. In a first approximation, they can be considered representative of the whole SiC network because it has been observed that damage accumulations on the Si and C sublattices are rather similar (see Figure 4.4). The data in Figure 4.6 refer to both 3.5° off-axis 6H-SiC and 8° off-axis 4H-SiC wafers implanted at 60° off the wafer normal. The dose rate was in the range 1 X 10 cm" sec" to 8 x 10 cm secbut...

Figure 4.7 Influence of the dose rate on damage accumulation in 4H-SIC for fixed ion mass and ion energy (a) damage at the peak of the Si sublattice versus increasing dose rate and increasing implantation temperature (b) evaluation of the energy activation for the phenomenon responsible of the shift versus temperature shown in part (a). (From [26], 2003 American Institute of Physics. Reprinted with permission.)...

Mechanistically, the formation of malonaldehyde and TBA-active DNA-bound material is not yet fully understood. While free malonaldehyde increases linearly with dose (G = 0.1 x 10 7 mol J 1 = 1.7% of OH), the efficiency of forming TBA-active DNA-bound material markedly decreases with increasing dose, that is when the integrity of the DNA is getting lost upon damage accumulation. At one stage, 02- seems to play a role, since the yield of total TBA-active material is G = 0.3 x 10"7 mol J-1 in N20/02-saturated and 0.2 x 10"7 mol J 1 in ( -saturated solution (at 100 Gy). As compared to N20/02, the OH yield is about half in 02-saturated solutions, but the 02 yield is markedly enhanced (Chap. 2.2). This could point to hydroperoxides as precursors of the TBA-active material, but details remain open. Yet, a G value of 0.2 x 10"7 mol J 1 (02-saturated) indicates that this type of lesion is not an unimportant one, about 7% of OH. 

We will construct an example to demonstrate a progressive degradation (damage accumulation) modeling approach to combine multiple degradation effects. We consider chemical degradation due to,... 

Fig. 4.5 Stress and inclusion analysis studies can be independently performed on this control arm, but both would give an erroneous location of failure, because damage accumulation is dependent upon both entities...

The paper deals with the study of process modifications of the elastic-mechanical characteristics of materials, the damage accumulation, the output of the limit state criteria for them. 

To track the progression of corrosion damage accumulation on anodized surfaces it is often desirable to use more simplified analysis approaches, especially when many replicate samples are to be examined. Since the effects of sealing are confined to the highest measured frequencies and those due to corro-... 

Free radicals may play a role in diseases and accelerate aging. In the course of everyday life, reactive oxygen species are encountered in the environment and produced in the body. These compounds break down into short-lived hydroxyl radicals, which can react with the body s proteins and DNA. The resulting damage accumulates and may result in heart disease, cancer, and premature aging. 

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