Aβ-40 Y10F Increases βfibrils Formation but Attenuates the Neurotoxicity of Amyloid-β Peptide

Alzheimer’s disease (AD) is characterized by the abnormal aggregation of amyloid-β peptide (Aβ) in extracellular deposits known as senile plaques. The tyrosine residue (Tyr-10) is believed to be important in Aβ-induced neurotoxicity due to the formation of tyrosyl radicals. To reduce the likelihood of cross-linking, here we designed an Aβ-40 analogue (Aβ-40 Y10F) in which the tyrosine residue was substituted by a structurally similar residue, phenylalanine. The aggregation rate was determined by the Thioflavin T (ThT) assay, in which Aβ-40 Y10F populated an ensemble of folded conformations much quicker and stronger than the wild type Aβ. Biophysical tests subsequently confirmed the results of the ThT assay, suggesting the measured increase of β-aggregation may arise predominantly from enhancement of hydrophobicity upon substitution and thus the propensity of intrinsic β-sheet formation. Nevertheless, Aβ-40 Y10F exhibited remarkably decreased neurotoxicity compared to Aβ-40 which could be partly due to the reduced generation of hydrogen peroxide. These findings may lead to further understanding of the structural perturbation of Aβ to its fibrillation

Research on the classic power supply modes of AC/DC distribution network

With the rapid development of distributed generation and power electronic technology, it is a tendency to develop the DC distribution network based on the AC type. And it is an urgent need to solve the problem of reasonably planning of AC/DC distribution network. In this paper, the application scenarios of AC/DC distribution network are analyzed based on the distribution characters of power sources and loads. The basic modules are analyzed, and the DC voltage grade sequences, electric power network structure, equipment, configuration of distribution automation are proposed. Furthermore, 5 classic power supply modes are proposed according to the analyzed application scenarios. The research results provide technical reference for the future AC/DC distribution network planning and design

Day-ahead optimal dispatching of AC/DC hybrid system

In this paper, a distributed energy resource (DER) optimal scheduling method for AC/DC hybrid systems with power electronic transformer (PET) is proposed. Firstly, a PET scheduling model considering loss is established. Secondly, an optimal scheduling model of the AC/DC hybrid system with PET is established. Finally, the optimal scheduling model of the AC/DC system with PET is verified by a case and the effect of PET efficiency on the operating state of the system is discussed. The results show that using the power regulation ability of PET, the distributed generation can be fully absorbed and the operating cost of the system can be reduced

Short-term Forecast of Multiple Loads in Integrated Energy System Based on IPSO-WNN

Accurate short-term energy load forecasting has a considerable influence on the economic scheduling and optimal operation of integrated energy system. This study proposes an improved particle swarm optimization-wavelet neural network (IPSO-WNN) method for short-term load forecasting of integrated energy system. First, Kendall rank correlation coefficient in Copula theory is used to analyze the correlation among the influencing factors, through which the influencing factors with strong correlation are selected as input variables of the model. Secondly, chaos algorithm and adaptive weight selection strategy are introduced in the POS-WNN forecasting model to improve the prediction accuracy. Therefore, a short-term load forecasting model of integrated energy system based on IPSO-WNN is established. Finally, the analysis of examples shows that the load prediction accuracy is significantly improved based on the IPSO-WNN model compared with the traditional forecasting model

Chitosan Oligosaccharides Inhibit/Disaggregate Fibrils and Attenuate Amyloid β-Mediated Neurotoxicity

Alzheimer’s disease (AD) is characterized by a large number of amyloid-β (Aβ) deposits in the brain. Therefore, inhibiting Aβ aggregation or destabilizing preformed aggregates could be a promising therapeutic target for halting/slowing the progression of AD. Chitosan oligosaccharides (COS) have previously been reported to exhibit antioxidant and neuroprotective effects. Recent study shows that COS could markedly decrease oligomeric Aβ-induced neurotoxicity and oxidative stress in rat hippocampal neurons. However, the potential mechanism that COS reduce Aβ-mediated neurotoxicity remains unclear. In the present study, our findings from circular dichroism spectroscopy, transmission electron microscope and thioflavin T fluorescence assay suggested that COS act as an inhibitor of Aβ aggregation and this effect shows dose-dependency. Moreover, data from thioflavin T assay indicated that COS could significantly inhibit fibrils formation and disrupt preformed fibrils in a dose-dependent manner. Furthermore, the addition of COS attenuated Aβ1-42-induced neurotoxicity in rat cortical neurons. Taken together, our results demonstrated for the first time that COS could inhibit Aβ1-42 fibrils formation and disaggregate preformed fibrils, suggesting that COS may have anti-Aβ fibrillogenesis and fibril-destabilizing properties. These findings highlight the potential role of COS as novel therapeutic agents for the prevention and treatment of AD