670 nm laser light and EGCG complementarily reduce amyloid-β aggregates in human neuroblastoma cells: basis for treatment of Alzheimer's disease?

Objective: The aim of the present study is to present the results of in vitro experiments with possible relevance in the treatment of Alzheimer's disease (AD). Background Data: Despite intensive research efforts, there is no treatment for AD. One root cause of AD is the extra- and intracellular deposition of amyloid-beta (A{beta}) fibrils in the brain. Recently, it was shown that extracellular A{beta} can enter brain cells, resulting in neurotoxicity. Methods: After internalization of A{beta}(42) into human neuroblastoma (SH-EP) cells, they were irradiated with moderately intense 670-nm laser light (1000 Wm(-2)) and/or treated with epigallocatechin gallate (EGCG). Results: In irradiated cells, A{beta}(42) aggregate amounts were significantly lower than in nonirradiated cells. Likewise, in EGCG-treated cells, A{beta}(42) aggregate amounts were significantly lower than in non-EGCG-treated cells. Except for the cells simultaneously laden with A{beta}(42) and EGCG, there was a significant increase in cell numbers in response to laser irradiation. EGCG alone had no effect on cell proliferation. Laser irradiation significantly increased ATP levels in A{beta}(42)-free cells, when compared to nonirradiated cells. Laser-induced clearance of Aβ(42) aggregates occurred at the expense of cellular ATP. Conclusions: Irradiation with moderate levels of 670-nm light and EGCG supplementation complementarily reduces A{beta} aggregates in SH-EP cells. Transcranial penetration of moderate levels of red to near-infrared (NIR) light has already been amply exploited in the treatment of patients with acute stroke; the blood-brain barrier (BBB) penetration of EGCG has been demonstrated in animals. We hope that our approach will inspire a practical therapy for AD

Microstructural evolution of a delta containing nickel-base superalloy during heat treatment and isothermal forging

The next generation of aerospace gas turbine engines need to operate at higher temperatures and stresses to improve their efficiency and reduce emissions. These operating conditions are beyond the capability of existing nickel-base superalloys, requiring the development of new high temperature materials. Controlling the microstructures of these new materials is key to obtaining the required properties and, therefore, it is critical to understand how these alloys respond to processing and heat treatment. Here, the microstructural evolution of V207M, a new δ containing, nickel-base superalloy, has been investigated following heat treatment and forging. The solvus temperatures of the γ′ and δ phases, determined by differential scanning calorimetry and microscopy, were found to be ~985 and ~1060 °C respectively. Isothermal forging of the alloy was conducted at 1000, 1050 and 1100 °C, corresponding to different volume fractions of retained δ. Considerable softening was observed prior to steady state flow when forging at 1000 °C, whilst only steady state flow occurred at 1050 and 1100 °C. The steady state flow process was believed to be dominated by dynamic recovery in the γ phase, with an activation energy of 407 kJmol−1. Samples that exhibited flow softening also showed a significant change in the orientation of the δ precipitates, preferentially aligning normal to the forging axis, and this reorientation was thought to be the cause of the observed flow softening

Recrystallization of amorphous nano-tracks and uniform layers generated by swift-ion-beam irradiation in lithium niobate.

The thermal annealing of amorphous tracks of nanometer-size diameter generated in lithium niobate (LiNbO3) by Bromine ions at 45 MeV, i.e., in the electronic stopping regime, has been investigated by RBS/C spectrometry in the temperature range from 250°C to 350°C. Relatively low fluences have been used (<1012 cm−2) to produce isolated tracks. However, the possible effect of track overlapping has been investigated by varying the fluence between 3×1011 cm−2 and 1012 cm−2. The annealing process follows a two-step kinetics. In a first stage (I) the track radius decreases linearly with the annealing time. It obeys an Arrhenius-type dependence on annealing temperature with activation energy around 1.5 eV. The second stage (II) operates after the track radius has decreased down to around 2.5 nm and shows a much lower radial velocity. The data for stage I appear consistent with a solid-phase epitaxial process that yields a constant recrystallization rate at the amorphous-crystalline boundary. HRTEM has been used to monitor the existence and the size of the annealed isolated tracks in the second stage. On the other hand, the thermal annealing of homogeneous (buried) amorphous layers has been investigated within the same temperature range, on samples irradiated with Fluorine at 20 MeV and fluences of ∼1014 cm−2. Optical techniques are very suitable for this case and have been used to monitor the recrystallization of the layers. The annealing process induces a displacement of the crystalline-amorphous boundary that is also linear with annealing time, and the recrystallization rates are consistent with those measured for tracks. The comparison of these data with those previously obtained for the heavily damaged (amorphous) layers produced by elastic nuclear collisions is summarily discussed

THE CONTRIBUTION OF LATTICE MATCHING TO THE INTERFACIAL ENERGY BETWEEN DISSIMILAR MATERIALS

The interfacial energy of boundaries between dissimilar materials can be described as function of the lattice mismatch, the chemical interaction and the interfacial entropy of the boundaries. Based on experiments involving a sphere-rotation method and undercooling measurements of (solid/liquid) phase mixtures in a droplet dispersion, an attempt is made to separate the influence of the different contributions. The atomic structure of interphase boundaries between noble metals and ionic crystals can be described by the "lock-in" model : low energy interphase boundaries were found if close packed rows of atoms at the "surface" of the metal crystal lock into the "valleys" between close packed rows of atoms at the "surface" of the ionic crystal. At higher temperatures the relative stability of different interphase boundary structures may change depending on the degree of axial commensuration and the related interfacial entropies. Hence, the contribution of lattice matching to the interfacial energy can decrease or vanish completely in some cases, resulting in a commensurate/incommensurate phase transition (e.g. for Au/Al2O3). Furthermore, the droplet undercooling experiments demonstrate that good matching between two crystal lattices (substrate/nucleus) can favour formation of metastable phases due to the lowering of the activation barrier for nucleation during crystallization from a highly undercooled liquid

COMMON FACTORS CONTROLLING GRAIN AND PHASE BOUNDARY ENERGY

The low energy interfaces identified recently for the case of silver-silver grain boundaries as well as gold-LiF and silver-nickel interfaces by the method of sintering of spheres to flat substrate, were analysed in a unified way. The special properties of some of those interfaces can be understood by taking into account that the following factors lead to a decrease of the interfacial energy : i. a high fraction of atoms of one crystal locked in valleys on the surface of the other crystal, ii. the locked atoms form close packed rows thus decreasing the elastic strain energy, iii. in sectors separated by the locked atomic rows both crystals surfaces are parallel to low energy planes, iv. the energy necessary to "unlock" an atom is higher than the energy of thermal vibrations

ENERGY AND STRUCTURE OF INTERPHASE BOUNDARIES

The energy of interphase boundaries between noble metals (Au, Cu) and various ionic crystals (LiF, NaCl, KCl, MgO, Al2O3, mica) was investigated by means of the plate/sphere method. The results obtained suggest that the coincidence model is not applicable to describe the structure of interphase boundaries of low energy between noble metals and ionic crystals. The atomic structure of the low energy boundaries observed may be understood in terms of the proposed "lock-in model". Moreover the energy of interphase boundaries seems to be strongly dependant on the temperature. Measurements of the energy of Cu/MgO and Au/Al2O3 interphase boundaries at 550°C and 950°C indicate the existence of a transition from an energetically anisotropic boundary structure into an isotropic one