11.2.1 Intrinsic Mechanisms

General description. Incomplete penetration describes the condition in which the weld fails to reach the bottom of the weld joint, resulting in a notch located at the root of the weld (Fig. 15.12). This critical defect can substantially reduce the intrinsic mechanical strength of the joint and can combine with environmental factors to produce corrosion fatigue (Chap. 10), stress-corrosion cracking (Chap. 9), or crevice corrosion (Chap. 2). 

Distinguish between the extrinsic and intrinsic mechanisms of blood coagulation... 

Activated factor XII leads to the activation of factor XI in turn, activated factor XI, along with Ca++ ions and factor IV, leads to activation of factor IX. Activated factor IX, along with Ca++ ions, factor VIII, and PF3, leads to the activation of factor X. From the point of factor X activation, the extrinsic and intrinsic mechanisms follow the same pathway to fibrin formation. 

Smoothness of the endothelial lining prevents contact activation of the intrinsic mechanism. 

Several studies suggest that cortistatin expression correlates with the sleep homeostat. The concentration of cortistatin mRNA oscillates with the light-dark cycle in rats, with maximal levels at the end of the dark (i.e. active) period. Further, the steady-state concentration of cortistatin mRNA increases four-fold after sleep deprivation, and returns to normal levels after sleep rebound, indicating that the expression of the peptide is associated with sleep demand (Spier de Lecea, 2000). Preliminary studies in cortical slices suggest that cortistatin-14 increases cortical synchronization by enhancing the H-current. Thus, cortistatin and somatostatin may be part of the intrinsic mechanisms of the cerebral cortex that are involved in the maintenance of excitability. 

Khatiwala, C.B., Peyton, S.R., and Putnam, A.J. (2006) Intrinsic mechanical properties of the extracellular matrix affect the behavior of pre-osteoblastic MC3T3-E1 cells. Am. J. Physiol. Cell Physiol. 290, C1640-C1650. 

The intrinsic mechanical properties of plastics and composites are different from those of conventional materials ... 

Schroder D, Schwarz H (2007) Intrinsic Mechanisms of Oxidation Reactions as Revealed by Gas-Phase Experiments. 22 1-15... 

In many physicochemical interactions which are subject to the same intrinsic mechanism, the free energy change is proportional to the enthalpy. 

Considering the second requirement, that is, good dynamic mechanical properties ePTFE-based arterial prostheses must satisfy to improve their functional patency, there are not so many ways to reach this goal. Unfortunately, and due to the intrinsic mechanical characteristics of PTFE, the mechanical behaviour of these prostheses cannot be easily modified. However, different ways have been explored on the one hand, an optimisation of the design of the prostheses... 

Intrinsic Mechanisms of Oxidation Reactions as Revealed by Gas-Phase Experiments... 

Abstract Oxidation catalysis is of extreme importance in many areas of chemistry. The intrinsic mechanisms of oxidation reachons are, however, quite often understood only rather poorly, and catalyst research is mostly, if not exclusively, based on enhrely empirical approaches. In this respect, gas-phase experiments can provide a complementary approach in that they can allow the investigation of the elementary processes in oxidation catalysis step by step. By such, some general insight can be obtained, which may assist in the development of more efficient oxidahon catalysts. 

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