The role of the CC chemokine CCL17 in a mouse model of Alzheimer’s disease

In Alzheimer's disease (AD), inflammatory processes are critically involved by cells releasing neurotoxic or neurotrophic factors influencing survival of neurons and synapses, and thereby cognitive behavior. Several chemokines and their receptors have been shown to be upregulated in AD and play a crucial role in plaque deposition, microglia and astrocyte activation, and cognitive behavior in AD mouse models. Mice, expressing the human Amyloid precursor protein (APP) and presenilin-1 (PS1) and deficient for the endogenous CC chemokine CCL17 (APP/PS1-CCL17E/E mice) showed a WT-like learning and memory performance in Morris water maze together with reduced levels of soluble Abeta oligomers and Abeta42 peptides at 12-14 months of age, when cognitive deficits and plaque deposition are fully developed in normal APP/PS1. Surprisingly, APP/PS1-CCL17E/E mice exhibit equivalent reactive GFAP-positive astrocytes, but enhanced microgliosis. CD11b-positive microglial cells derive from CNS-resident microglia and from peripheral Ly6C(high) CCR2-positive monocytes / macrophages infiltrating the CNS of APP/PS1-CCL17E/E mice. Increased CCL22, but not CCL2 expression was found in the hippocampus of APP/PS1-CCL17E/E mice, suggesting a potential convergent recruitment mechanism of Ly6C(high) CCR2-positive CCR4-positive monocytes. For the first time, it could be demonstrated that microglia isolated from the CNS of APP/PS1 mice express CCL17. The cognate receptor CCR4 is expressed by neonatal microglia upon LPS stimulation, indicating a para- or autocrine signaling. As indicated by increased hippocampal IL-6 and IL-10 expression, APP/PS1-CCL17E/E mice showed an altered inflammatory response in the CNS. Furthermore, CCL17E/E microglia, but not macrophages, showed enhanced expression of IL-10 (in vitro) and MMR expression (in vivo). Phagocytosis assay of fluorescence-labeled Abeta1-42 peptide revealed an increased uptake by neonatal microglia, but not by BM-derived macrophages of CCL17E/E mice. The underlying mechanism possibly involves the recruitment of peripheral macrophages into the CNS, accompanied by a more anti-inflammatory and neurotrophic milieu. Furthermore, enhanced Abeta clearance is indicated by increased uptake and enhanced neprilysin expression level

Frictional properties of AZ80 and ZE10 magnesium alloys under dry and lubricated contact conditions

The frictional properties of two types of magnesium alloys, i.e. AZ80 and ZE10 were investigated. A purpose-developed sheet metal forming simulator was used to conduct the experiments under constant plastic deformation. Both lubricated and dry sliding contact conditions were simulated and the effect of key process parameters such as contact pressure and sliding velocity on the frictional properties of these alloys were investigated. Due to the different sliding velocities, the contact pressure rose during each experiment which enables the measurement of the coefficient of friction for a wide range of contact pressures. The results showed an increase in the friction coefficients of both alloys with increasing contact pressure. Furthermore, a decrease of the friction coefficient was observed for higher sliding velocities. (C) 2014 The Authors. Published by Elsevier Ltd.Ramezani, M.; Neitzert, T.; Pasang, T.; Sellés Cantó, MÁ. (2014). Frictional properties of AZ80 and ZE10 magnesium alloys under dry and lubricated contact conditions. Elsevier. doi:10.1016/j.proeng.2014.10.242

Defective Adaption of Erythrocytes During Acute Hypoxia Injury in an Elderly Population

The present study investigated the changes in several erythrocyte oxidative stress biomarkers in hypoxic elderly individuals to analyze the deleterious effects of low oxyhemoglobin saturation in an elderly population. We collected blood samples from one normoxic middle-aged group and two groups composed of individuals older than 75 years of age: one normoxic group and one hypoxic group. Aging appeared to provoke a defective erythrocyte antioxidant defense associated with increased oxidative damage in the elderly population. Acute hypoxia activated an insufficient antioxidant defense response as suggested by the oxidative damage observed. The oxidative imbalance presented in older participants and increased in hypoxia participants had a direct effect on glyceraldehyde-3-phosphate dehydrogenase cell distribution. Oxidative stress levels altered Band 3 protein and mediated caspase-3 activation in erythrocyte from the aged group although it was not extended to hypoxic individuals. Therefore, aged participants appeared to activate an insufficient antioxidant response against hypoxia-related oxidative stress.Instituto Carlos III (FISS-06-RD06/0013/0011); Ministerio de Agricultura and FEDER (INIA RTA2007-00087-C02-02); FICYT (Gobierno del Principado de Asturias) (IB09-134)

Defect Dynamics in Proton Irradiated CH3NH3PbI3 Perovskite Solar Cells

Perovskite solar cells have been shown to be of extraordinary radiation hardness, considering high energetic 68 MeV proton irradiation with doses up to 1013 p cm amp; 8722;2. In this study electrical and photoelectrical properties of perovskite solar cells with and without proton irradiation are analyzed in detail. The results reveal that proton irradiation improves the open circuit voltage, fill factor, and recombination lifetime of photogenerated charge carriers in perovskite solar cells. These enhancements are mainly a result of the lower nonradiative recombination losses in the proton irradiated devices. The proton treatment creates shallow traps, which may be associated with the proton induced point defects due to the displacements of atoms in the inorganic Pb I framework, which act as unintentional doping sources and partially compensate deep traps originated from the photodegradation of methylammonium molecule

Radiation Hardness and Self Healing of Perovskite Solar Cells

The radiation hardness of CH3 NH3 PbI3 -based solar cells is evaluated from in situ measurements during high-energy proton irradiation. These organic-inorganic perovskites exhibit radiation hardness and withstand proton doses that exceed the damage threshold of crystalline silicon by almost 3 orders of magnitude. Moreover, after termination of the proton irradiation, a self-healing process of the solar cells commences