Models for LRRK2-Linked Parkinsonism

Parkinson's disease (PD) is a progressive neurodegenerative movement disorder characterized by the selective loss of dopaminergic neurons and the presence of Lewy bodies. The pathogenesis of PD is not fully understood, but it appears to involve both genetic susceptibility and environmental factors. Treatment for PD that prevents neuronal death progression in the dopaminergic system and abnormal protein deposition in the brain is not yet available. Recently, mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified to cause autosomal-dominant late-onset PD and contribute to sporadic PD. Here, we review the recent models for LRRK2-linked Parkinsonism and their utility in studying LRRK2 neurobiology, pathogenesis, and potential therapeutics

The role of soot particles in the tribological behavior of engine lubricating oils

AbstractThis paper describes a study of the influence of soot contamination on the tribological behavior of engine lubricants. The candidate lubricants were a formulated engine lubricant, (CD SAE 15W-40) and a base oil (150SN). Soot particle contamination was simulated using carbon black with friction and wear measured using a four-ball tribometer. The results show that the antiwear and antifriction properties of the CD SAE 15W-40 formulated oil with varying carbon black contents were better than those of 150SN base oil. The antifriction properties of the SAE 15W‐40 formulated oil with the addition of 2wt% carbon black were strengthened. This was ascribed to uniformly dispersed carbon black and the additives in the CD SAE 15W-40. The antifriction properties of the 150SN base oil with 2, 4wt% carbon black content were upgraded via the addition of 2wt% dispersant polyisobutylene succinimide. The tribological effect of the carbon black in the lubricants was attributed to absorption and agglomerate effects

Effect of TiF₃ catalyst on the tribological properties of carbon black-contaminated engine oils

AbstractThe effects of a TiF3 catalyst on the tribological behaviour of carbon black-contaminated liquid paraffin and a fully formulated engine lubricating oil (CD SAE15W-40) were investigated using a four-ball tribological test. Scanning electronic microscopy with energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, surface roughness, and thermogravimetric analyses were used to investigate the surface element content, chemical valence state, surface roughness, and initial decomposition temperature of the oil samples, respectively. Results showed that the average wear scar diameter (AWSD) and friction coefficient of the two kinds of carbon black-contaminated lubricants decreased in the presence of 0.5wt% TiF3. The variation rates of the carbon black-contaminated liquid paraffin and fully formulated engine lubricating oil were 29.45% and 11.54%, respectively, and their initial decomposition temperatures decreased. These phenomena were ascribed to the decomposition of TiF3 catalyst into TiO2 and fluoride that resulted in the formation of improved boundary lubrication films. Moreover, for the fully formulated engine oil, the lubrication additive zinc dialkyldithiophosphate was catalyzed by TiF3, decomposing into polyphosphate, which aided the formation of mixture boundary lubrication films

Study on the Tribological Properties of F-T DS/ZnFe-LDH Composite Lubricating Material

The homemade soot capture device was used to burn Fischer-Tropsch synthetic diesel (F-T diesel) in order to simulate the combustion of F-T diesel in the engine and collect its soot (F-T DS, FS). The zinc-iron hydrotalcite (ZnFe-LDH) and the composite materials of FS and ZnFe-LDH (F-T DS/ZnFe-LDH, FS/ZnFe-LDH) were prepared by hydrothermal synthesis, and the similarities and differences in tribological characteristics of the above three lubricating materials such as 10# white oil (10# WO) lubricant additives were investigated. FS is an aggregation composed of amorphous carbon and graphite microcrystals. ZnFe-LDH is mainly composed of nanosheets, Zn, and Fe hydroxide particles, with a high degree of crystallization, while FS/ZnFe-LDH is a “sandwich layer” composed of nanosheets and soot particles. Because of the addition of cetyltrimethylammonium bromide and the grafting of a long carbon chain lipophilic group in the preparation process, FS/ZnFe-LDH has better anti-wear properties than the FS and ZnFe-LDH Effect. When FS/ZnFe-LDH is added at 0.2 wt.%, the average friction coefficient (AFC) and average wears scar diameter (AWSD) are at their lowest. Compared with pure 10# WO, the minimum values of AFC and AWSD have dropped by 36.84% and 22.58%, respectively. XPS analysis of the wear scar surface shows that when ZnFe-LDH and FS/ZnFe-LDH are used as lubricating additives of 10# WO, together with the organic matter in the white oil and the iron element in the friction pair, tribochemistry occurs under the combined action of the adsorption force and the tribochemical reaction, a friction protection film containing four elements of C, O, Fe, and Zn is formed on the surface of the wear scar, which effectively reduces the wear and reduces the friction coefficient

Study on the Tribological Properties of F-T DS/ZnFe-LDH Composite Lubricating Material

The homemade soot capture device was used to burn Fischer-Tropsch synthetic diesel (F-T diesel) in order to simulate the combustion of F-T diesel in the engine and collect its soot (F-T DS, FS). The zinc-iron hydrotalcite (ZnFe-LDH) and the composite materials of FS and ZnFe-LDH (F-T DS/ZnFe-LDH, FS/ZnFe-LDH) were prepared by hydrothermal synthesis, and the similarities and differences in tribological characteristics of the above three lubricating materials such as 10# white oil (10# WO) lubricant additives were investigated. FS is an aggregation composed of amorphous carbon and graphite microcrystals. ZnFe-LDH is mainly composed of nanosheets, Zn, and Fe hydroxide particles, with a high degree of crystallization, while FS/ZnFe-LDH is a “sandwich layer” composed of nanosheets and soot particles. Because of the addition of cetyltrimethylammonium bromide and the grafting of a long carbon chain lipophilic group in the preparation process, FS/ZnFe-LDH has better anti-wear properties than the FS and ZnFe-LDH Effect. When FS/ZnFe-LDH is added at 0.2 wt.%, the average friction coefficient (AFC) and average wears scar diameter (AWSD) are at their lowest. Compared with pure 10# WO, the minimum values of AFC and AWSD have dropped by 36.84% and 22.58%, respectively. XPS analysis of the wear scar surface shows that when ZnFe-LDH and FS/ZnFe-LDH are used as lubricating additives of 10# WO, together with the organic matter in the white oil and the iron element in the friction pair, tribochemistry occurs under the combined action of the adsorption force and the tribochemical reaction, a friction protection film containing four elements of C, O, Fe, and Zn is formed on the surface of the wear scar, which effectively reduces the wear and reduces the friction coefficient

Real-Time Indoor Positioning Approach Using iBeacons and Smartphone Sensors

For localization in daily life, low-cost indoor positioning systems should provide real-time locations with a reasonable accuracy. Considering the flexibility of deployment and low price of iBeacon technique, we develop a real-time fusion workflow to improve localization accuracy of smartphone. First, we propose an iBeacon-based method by integrating a trilateration algorithm with a specific fingerprinting method to resist RSS fluctuations, and obtain accurate locations as the baseline result. Second, as turns are pivotal for positioning, we segment pedestrian trajectories according to turns. Then, we apply a Kalman filter (KF) to heading measurements in each segment, which improves the locations derived by pedestrian dead reckoning (PDR). Finally, we devise another KF to fuse the iBeacon-based approach with the PDR to overcome orientation noises. We implemented this fusion workflow in an Android smartphone and conducted real-time experiments in a building floor. Two different routes with sharp turns were selected. The positioning accuracy of the iBeacon-based method is RMSE 2.75 m. When the smartphone is held steadily, the fusion positioning tests result in RMSE of 2.39 and 2.22 m for the two routes. In addition, the other tests with orientation noises can still result in RMSE of 3.48 and 3.66 m. These results demonstrate our fusion workflow can improve the accuracy of iBeacon positioning and alleviate the influence of PDR drifting

Synphilin-1 binds ATP and regulates intracellular energy status.

Recent studies have suggested that synphilin-1, a cytoplasmic protein, is involved in energy homeostasis. Overexpression of synphilin-1 in neurons results in hyperphagia and obesity in animal models. However, the mechanism by which synphilin-1 alters energy homeostasis is unknown. Here, we used cell models and biochemical approaches to investigate the cellular functions of synphilin-1 that may affect energy balance. Synphilin-1 was pulled down by ATP-agarose beads, and the addition of ATP and ADP reduced this binding, indicating that synphilin-1 bound ADP and ATP. Synphilin-1 also bound GMP, GDP, and GTP but with a lower affinity than it bound ATP. In contrast, synphilin-1 did not bind with CTP. Overexpression of synphilin-1 in HEK293T cells significantly increased cellular ATP levels. Genetic alteration to abolish predicted ATP binding motifs of synphilin-1 or knockdown of synphilin-1 by siRNA reduced cellular ATP levels. Together, these data demonstrate that synphilin-1 binds and regulates the cellular energy molecule, ATP. These findings provide a molecular basis for understanding the actions of synphilin-1 in energy homeostasis

Influence of Complete Coriolis Force on the Dispersion Relation of Ocean Internal-wave in a Background Currents Field

In this thesis, the influence of complete Coriolis force (the model includes both the vertical and horizontal components of Coriolis force) on the dispersion relation of ocean internal-wave under background currents field are studied, it is important to the study of ocean internal waves in density-stratified ocean. We start from the control equation of sea water movement in the background of the non-traditional approximation, and the vertical velocity solution is derived where buoyancy frequency N(z) gradually varies with the ocean depth z. The results show that the influence of complete Coriolis force on the dispersion relation of ocean internal-wave under background currents field is obvious, and these results provide strong evidence for the understanding of dynamic process of density stratified ocean internal waves

Influence of Complete Coriolis Force on the Dispersion Relation of Ocean Internal-wave in a Background Currents Field

In this thesis, the influence of complete Coriolis force (the model includes both the vertical and horizontal components of Coriolis force) on the dispersion relation of ocean internal-wave under background currents field are studied, it is important to the study of ocean internal waves in density-stratified ocean. We start from the control equation of sea water movement in the background of the non-traditional approximation, and the vertical velocity solution is derived where buoyancy frequency N(z) gradually varies with the ocean depth z. The results show that the influence of complete Coriolis force on the dispersion relation of ocean internal-wave under background currents field is obvious, and these results provide strong evidence for the understanding of dynamic process of density stratified ocean internal waves