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Reduced brain insulin signaling and low CSF-to-plasma insulin ratios have been observed in patients with Alzheimer disease (AD). Furthermore, intracerebroventricular or IV insulin administration improve memory, alter evoked potentials, and modulate neurotransmitters, possibly by augmenting low brain levels. After intranasal administration, insulin-like peptides follow extracellular pathways to the brain within 15 minutes.

Hyperinsulinemia and insulin resistance are risk factors for memory impairment and Alzheimer disease (AD). Insulin regulates levels of the amyloid β-peptide (Aβ) in vitro in neuronal cultures and in vivo in the CSF of normal older adults.

Abstract: The interaction between fatigue and oxidation has been studied in IN 100,* a cast nickel based su-peralloy tested in laboratory air at 1000 C. The effect of fatigue cycling on oxidation was studied by quantitative metallography on polished specimens which were oxidized in a furnace and on strain cycled low cycle fatigue specimens. Thickness measurements have shown that matrix oxidation obeys a parabolic kinetics and is strongly enhanced by fatigue cycling. Measurements of oxide spikes have shown that interdendritic oxidation obeys at 1/4 kinetics and is weakly affected by cyclic straining. A phenomenological equation was proposed which accounts for this interaction through fatigue induced fracture events in the oxide scale. Analysis of the distribution histograms shows that the actual life to crack initiation is identical to the number of cycles to break the matrix oxide scale in the most critical areas.

This paper deals with a possible generalization of the traditional grain growth kinetic functions. A novel probabilistic model devoted to the grain growth prediction in alloys is presented. It is based on the extension of the traditional power law kinetic equation proposed by Beck. The Beck's isothermal kinetic equation is defined as D(t)=A*exp(-E/RT)*tm where D(t) is the grain size (diameter), t is the time, E is the activation energy, A is the preexponential factor, m is the time exponent, R is the universal gas constant and T is the absolute temperature. The novel probabilistic model proposed is based on the concept of the mixture of probability density functions. In this model it is assumed that during grain growth the activation energy (E) is not constant, but its distribution is determined by the initial grain morphology of alloys. More exactly speaking, it is supposed that the activation energy is a random variable which is characterized by the probability density function g(E) of the activation energy. By using appropriately selected probability density functions, different types of generalized grain growth kinetic equations can be established. Based on computer simulations, the application of the extended grain growth kinetic models is demonstrated by examples.

Defect free casting requires an excellent accordance between steel properties being cast and the technological parameters, especially from the aspect of inner quality and homogeneity of cast products. Typical serious defects of cast slabs is the centerline segregation (CLS). The centerline segregation in slabs develops in a very complicated way, the main factors influencing the CLS pattern are the macrosegregation and the shrinkage of solidifying melt in the mushy area. The centerline section of the slab can be characterized by different chemical composition compared to the average composition and it can contain shrinkage holes, discontinuities and inclusions. In the hot rolling process the complex shape of interdendritic holes will be modified depending on the strain applied. In chemical composition the difference remains and it can be identified even after the soaking period (over 1050 degC). As an example, the center part of an St52 grade hot rolled heavy plates and strips containing CLS can be characterized by a carbon content of 0,3-0,5 wt% and manganese content of 1,7-1,9 wt%. The segregation level - including the carbon content - can hardly be decreased by post heat treatment or annealing.

The Johnson-Mehl-Avrami-Kolmogorov (JMAK) kinetic equation is generally used for describing the progress of solid state diffusion-controlled transformations. The traditional JMAK model is applicable for modeling only monophase decomposition (precipitation) processes. This paper deals with possible generalizations of the classical JMAK kinetic model by taking into consideration the simultaneous occurrence of more parallel transformations. It is revealed that the Jones-Bhadeshia kinetic model belonging to the family of the strongly coupled multiphase models has only a limited practical application because it contains only few fitting parameters. Moreover, it has been shown and demonstrated that for predicting decomposition processes it is more advantageous to use a multiphase kinetic model including a finite set of ordinary autonomous differential equations.

Corrosion degradation was observed in a nuclear power plant spent fuel cooling system. A systematic and comprehensive investigation program was developed to reveal the root cause of the degradation. Series of corrosion tests, mechanical, microstructural and microbiological investigations were carried out. Also, simulations of the operating conditions and welding parameters were performed. Based on the results, the major contributors to the degradation process were identified and a possible degradation mechanism was proposed.