Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglial surface receptor genetically linked to the risk for Alzheimer’s disease (AD). A proteolytic product, soluble TREM2 (sTREM2), is abundant in the cerebrospinal fluid and its levels positively correlate with neuronal injury markers. To gain insights into the pathological roles of sTREM2, we studied sTREM2 in the brain of 5xFAD mice, a model of AD, by direct stereotaxic injection of recombinant sTREM2 protein or by adeno-associated virus (AAV)-mediated expression. We found that sTREM2 reduces amyloid plaque load and rescues functional deficits of spatial memory and long-term potentiation. Importantly, sTREM2 enhances microglial proliferation, migration, clustering in the vicinity of amyloid plaques and the uptake and degradation of Aβ. Depletion of microglia abolishes the neuroprotective effects of sTREM2. Our study demonstrates a protective role of sTREM2 against amyloid pathology and related toxicity and suggests that increasing sTREM2 can be explored for AD therapy.
An active absorption device is proposed based on vanadium dioxide metamaterials. By controlling the conductivity of vanadium dioxide, resonant absorbers are designed to work at wide range of terahertz frequencies. Numerical results show that a broadband terahertz absorber with nearly 100% absorptance can be achieved, and its normalized bandwidth of 90% absorptance is 60% under normal incidence for both transverse-electric and transverse-magnetic polarizations when the conductivity of vanadium dioxide is equal to 2000 Ωcm. Absorptance at peak frequencies can be continuously tuned from 30% to 100% by changing the conductivity from 10 Ωcm to 2000 Ωcm. Absorptance spectra analysis shows a clear independence of polarization and incident angle. The presented results may have tunable spectral applications in sensor, detector, and thermophotovoltaic device working at terahertz frequency bands.
The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C 66 H 4 from a soot of a low-pressure combustion of benzene−acetylene−oxygen. Unambiguously characterized by single-crystal X-ray diffraction, the C 66 H 4 renders a nonclassical geometry incorporating two heptagons and two pairs of fused pentagons in a C 2v symmetry. The common vertexes of the fused pentagons are bonded with four hydrogen atoms to convert the hydrogen-linking carbon atoms from sp 2 to sp 3 hybridization, which together with the adjacent heptagons essentially releases the sp 2 -bond strains on the abutting-pentagon sites of the diheptagonal fused pentagon C 66 (dihept-C 66 ). DFT computations suggest the possibility for an in situ hydrogenation process leading to stabilization of the dihept-C 66 . In addition, the experiments have been carried out to study heptagon-dependent properties of dihept-C 66 H 4 , indicating the key responsibility of the heptagon for changing hydrocarbon activity and electronic properties. The present work with the unprecedented doubleheptagon-containing hydrofullerene successfully isolated and identified as one of the low-pressure combustion products shows that the heptagon is a new building block for constructing fullerene products in addition to pentagons and hexagons in lowpressure combustion systems.
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