Cellular localization of p-tau217 in brain and its association with p-tau217 plasma levels

Recent studies highlight phosphorylated tau (p-tau) at threonine tau 217 (p-tau217) as a new promising plasma biomarker for pathological changes implicated in Alzheimer’s disease (AD), but the specific brain pathological events related to the alteration in p-tau217 plasma levels are still largely unknown. Using immunostaining techniques of postmortem AD brain tissue, we show that p-tau217 is found in neurofibrillary tangles (NFTs) and neuropil threads that are also positive for p-tau181, 202, 202/205, 231, and 369/404. The p-tau217, but not the other five p-tau variants, was also prominently seen in vesicles structure positive for markers of granulovacuolar degeneration bodies and multi-vesicular bodies. Further, individuals with a high likelihood of AD showed significantly higher p-tau217 area fraction in 4 different brain areas (entorhinal cortex, inferior temporal gyrus, and superior frontal gyrus) compared to those with Primary age related tauopathy or other non-AD tauopathies. The p-tau217 area fraction correlated strongly with total amyloid-beta (Aβ) and NFT brain load when the whole group was analyzed. Finally, the mean p-tau217 area fraction correlated significantly with p-tau217 concentrations in antemortem collected plasma specifically in individuals with amyloid plaques and not in those without amyloid plaques. These studies highlight differences in cellular localization of different p-tau variants and suggest that plasma levels of p-tau217 reflect an accumulation of p-tau217 in presence of Aβ plaque load.

Study on MnS Inclusion Aggregation along Continuous Casting Slab Thickness of Medium Carbon Structural Steel

Precipitation of MnS inclusions in steel affects the mechanical properties of the material significantly. The evolution of MnS inclusions along the continuous casting slab thickness and its influencing factors has not been clearly established and comprehensively studied. In this paper, solidification macrostructure, sulfur segregation and MnS inclusions in the continuous casting slab of medium carbon structural steel 45# were studied by various methods, including the metallographic observations, elemental analysis, scanning electron microscope (SEM) with Energy Dispersive Spectrometer (EDS) observation, automatic particle analysis, and thermodynamic calculations. The 2D/3D morphologies of MnS inclusions suggest that the sulfides turn from globular to rodlike, and further to dendritic shape along the slab thickness progressively. Furthermore, it was found that MnS inclusions are remarkably aggregated in the columnar crystals and the equiaxed crystals mixed zone, where the sulfides have the largest average diameter of 6.35 μm and the second maximum area fraction of 0.025% along the slab thickness. In order to reveal the mechanism of this phenomenon, the precipitation temperature of MnS inclusion in the 45# steel was clarified by thermodynamic calculation and experimental observation, and the quantitative relationships among the distribution of sulfur content, secondary dendrite arm spacing (SDAS), and precipitation area fraction of MnS inclusions were discussed. Moreover, the inclusion size was numerically predicted to compare with the measured value. The results indicate that the large SDAS, high sulfur content and low cooling rate accounting for the large-size aggregated MnS inclusions in the mixed zone. Unfortunately, the dendritic MnS inclusions, even if the average diameter exceeds 52 μm, can act as the nucleation sites for ferrites, and the distribution of the sulfides promotes uneven microstructure in the steel.

Microstructure Evolution of AlSn20Cu Alloy Prepared by Conventional Casting and Semi Continuous Casting during Rolling and Annealing

AlSn20Cu alloy is currently one of the most widely used bearing materials, and its microstructure is the most important indicator in application. In this paper, AlSn20Cu alloy ingots were prepared by two methods: ordinary casting and semi-continuous casting, and deformation and annealing process of the two ingots were studied. Scanning electron microscope (SEM) and Image Pro Plus software were used to observe and analyze the evolution of the microstructure, and the morphological information such as the average grain size and area fraction of the Sn phase was quantitatively characterized. The effects of casting method, deformation temperature, deformation amount and annealing temperature on the morphology of Sn phase were studied in this paper. Compared with ordinary casting, the cooling rate of semi-continuous casting is higher, so the Sn phase is smaller, the casting defects are less, and the deformability of the alloy is better. The AlSn20Cu alloy prepared by ordinary casting has better deformability at about 140 °C, while the AlSn20Cu alloy prepared by semi-continuous casting can be rolled and deformed at room temperature. When the deformation is greater than 40%, after annealing at 250 °C, the average grain size of the Sn phase in the AlSn20Cu alloy prepared by semi-continuous casting is around one hundred square microns and the area fraction is more than 10%, and the Sn phase morphology is better than ordinary casting alloy under any processing conditions.

Quantitative Characterization of the γ’ Phase Distribution in the Large-Scale Area of the Second-Generation Nickel-Based Single Crystal Blade DD5

Nickel-based single crystal superalloy blades have excellent high-temperature performance as the hot end part of the aero-engine turbine. The most important strengthening phase in the single crystal blade is the γ’ phase, and its morphology and size distribution directly affect the high temperature performance of the single crystal blade. In this work, scanning electron microscopy (SEM) was used to obtain the microscopic images of the γ’ phase in multiple large continuous fields of view in the transverse sections of single crystal blades, and the quantitative statistical characterization of the γ’ phase was performed by image segmentation method based on deep learning. The 20 μm × 20 μm region was selected from the primary dendrite arm, the secondary dendrite arm, and the interdendrite to statistically analyze the γ’ phases. The statistical results show that the average size of the γ’ phase at the position of the interdendrite is significantly larger than the average size of the γ’ phase at the position of the dendrite; the sizes of the γ’ phase at the primary dendrite arm, the secondary dendrite arm and the interdendrite all obey the normal distribution; about 3.17 × 107 γ’ phases are counted in 20 positions in the 5 transverse sections of the single crystal blade in a total area of 5 mm2, and the size, geometric morphology and area fraction of all γ’ phases are respectively counted. In this work, the quantitative parameters of the γ’ phases at 4 different positions of the section of the single crystal superalloy DD5 blade were compared, the size and area fraction of the γ’ phases at the leading edge and the trailing edge were smaller, and the shape of the γ’ phase of the leading edge and the trailing edge is closer to the cube.

Analysis of structural differences of Ag Nanoparticles generated using Thermal and E-beam process based on SEM image

The variation in applications of nanoparticles (NPs) comes from differences in their microstructures. This may be observed in the terms of variation in size, area fraction and even the morphology of the particles. It is mainly the size and topography of these particles which govern the mechanical, and optoelectronic properties and have a huge impact in Bio-medical engineering.

Analysis of structural differences of Ag Nanoparticles generated using Thermal and E-beam process based on SEM imaging

The variation in applications of nanoparticles (NPs) comes from differences in their microstructures. This may be observed in the terms of variation in size, area fraction and even the morphology of the particles. It is mainly the size and topography of these particles which govern the Mechanical, Optoelectronics, properties and have a huge impact in Bio-medical engineering.

Abstract P170: Similarities And Differences In The Vascular Impact Of Estrogen Loss Versus G Protein-coupled Estrogen Receptor Deletion

Women in their postmenopausal years have an increased risk of cardiovascular disease, and recent research suggests that increased vascular stiffness can be detected within a year of the onset of menopause. We have previously demonstrated that the G Protein-Coupled Estrogen Receptor (GPER) protects the vasculature without noticeable changes in blood pressure, but little is known about the underlying structural changes that provide protection. In this study we assessed the impact of estrogen and the G protein-coupled estrogen receptor (GPER) on vascular health, with the hypothesis that loss of estrogen or deletion of smooth muscle cell (smc)-GPER would similarly increase vascular stiffness. Female mice were separated into three cohorts: intact wildtype, ovariectomized (OVX), and GPER smc-KO. OVX occurred at 8 weeks of age and 8 weeks later blood pressure was measured via tail-cuff plethysmography, arterial stiffness was measured as pulse wave velocity (PWV) via high resolution ultrasound, and carotids were excised for biaxial pressure myography and imaging. Uterine weight in OVX mice (0.03 g) was significantly lower than intact mice (0.1 g; p=0.0002) confirming the loss of estrogen. No difference was observed in systolic blood pressure, however, both the OVX (1.5 m/s) and smc-KO (1.9 m/s) groups had significantly higher PWV than intact controls (1.2 m/s; p=0.02 and p=0.03, respectively). Carotids of OVX (366 μm) and smc-KO (389 μm) mice had a smaller outer diameter versus controls (441 μm; p >0.05) without a difference in thickness. Despite the similar responses of OVX and smc-KO groups, Masson’s trichrome staining of carotid sections showed significantly more smooth muscle area fraction in OVX (p=0.005), but not KO mice, and no difference in collagen area fraction. These data indicate that while estrogen loss and smc-KO of GPER both increase arterial stiffness, increased smooth muscle due to estrogen loss is likely not modulated through GPER. Future experiments will aim to understand how other components, such as extracellular matrix genes, may be affected by loss of GPER.

Effect of Microstructure on the Dimensional Stability of Extruded Pure Aluminum

High-performance extruded aluminum alloys with complex textures suffer significant dimension variation under environmental temperature fluctuations, dramatically decreasing the precision of navigation systems. This research mainly focuses on the effect of the texture of extruded pure aluminum on its dimensional stability after various annealing processes. The result reveals that a significant increment in the area fraction of recrystallized grains with <100> orientation and a decrement in the area fraction of grains with <111> orientation were found with increasing annealing temperature. Moreover, with the annealing temperature increasing from 150 °C to 400 °C, the residual plastic strain after twelve thermal cycles with a temperature range of 120 °C was changed from −1.6 × 10−5 to −4.5 × 10−5. The large amount of equiaxed grains with <100> orientation was formed in the microstructure of the extruded pure aluminum and the average grain size was decreased during thermal cycling. The area fraction of grain with <100> crystallographic orientation of the sample annealed at 400 °C after thermal cycling was 30.9% higher than annealed at 350 °C (23.7%) or at 150 °C (18.7%). It is attributed to the increase in the proportion of recrystallization grains with <100> direction as the annealing temperature increases, provided more nucleation sites for the formation of fine equiaxed grains with <100> orientation. The main orientation of the texture was rotated from parallel to <111> to parallel to <100> after thermal cycling. The change in the orientation of grains contributed to a change in interplanar spacing, which explains the change in the dimension along the extrusion direction during thermal cycling.