Mixed pathology, with both Alzheimer’s disease and vascular abnormalities, is the most common cause of clinical dementia in the elderly. While usually thought to be concurrent diseases, the fact that ...changes in cerebral blood flow are a prominent early and persistent alteration in Alzheimer’s disease raises the possibility that vascular alterations and Alzheimer pathology are more directly linked. Here, we report that aged tau-overexpressing mice develop changes to blood vessels including abnormal, spiraling morphologies; reduced blood vessel diameters; and increased overall blood vessel density in cortex. Blood flow in these vessels was altered, with periods of obstructed flow rarely observed in normal capillaries. These changes were accompanied by cortical atrophy as well as increased expression of angiogenesis-related genes such as Vegfa, Serpine1, and Plau in CD31-positive endothelial cells. Interestingly, mice overexpressing nonmutant forms of tau in the absence of frank neurodegeneration also demonstrated similar changes. Furthermore, many of the genes we observe in mice are also altered in human RNA datasets from Alzheimer patients, particularly in brain regions classically associated with tau pathology such as the temporal lobe and limbic system regions. Together these data indicate that tau pathological changes in neurons can impact brain endothelial cell biology, altering the integrity of the brain’s microvasculature.
As the first example of a photocatalytic system for splitting water without additional cocatalysts and photosensitizers, the comparatively cost‐effective Cu2I2‐based MOF, Cu‐I‐bpy ...(bpy=4,4′‐bipyridine) exhibited highly efficient photocatalytic hydrogen production (7.09 mmol g−1 h−1). Density functional theory (DFT) calculations established the electronic structures of Cu‐I‐bpy with a narrow band gap of 2.05 eV, indicating its semiconductive behavior, which is consistent with the experimental value of 2.00 eV. The proposed mechanism demonstrates that Cu2I2 clusters of Cu‐I‐bpy serve as photoelectron generators to accelerate the copper(I) hydride interaction, providing redox reaction sites for hydrogen evolution. The highly stable cocatalyst‐free and self‐sensitized Cu‐I‐bpy provides new insights into the future design of cost‐effective d10‐based MOFs for highly efficient and long‐term solar fuels production.
No additives required: A low‐cost Cu2I2‐based MOF exhibits efficient photocatalytic H2 production without additional photosensitizers and cocatalysts. DFT calculations reveal a good band alignment with the water redox energy levels. The proposed mechanism demonstrates that Cu2I2 clusters in Cu‐I‐bpy (bpy=4,4′‐bipyridine) serve as photoelectron generators to accelerate copper(I) hydride interaction for hydrogen evolution.
A reduced graphene oxide (RGO)-ZnIn(2)S(4) nanosheet composite was successfully synthesized via an in situ controlled growth process. The as-obtained RGO-ZnIn(2)S(4) composite showed excellent ...visible light H(2) production activity in the absence of noble metal cocatalysts.
The single atom alloy of extended surfaces is known to provide remarkably enhanced catalytic performance toward heterogeneous hydrogenation. Here we demonstrate from first principles calculations ...that this approach can be extended to nanostructures, such as bimetallic nanoparticles. The catalytic properties of the single-Pd-doped Cu55 nanoparticles have been systemically examined for H2 dissociation as well as H atom adsorption and diffusion, following the concept of single atom alloy. It is found that doping a single Pd atom at the edge site of the Cu55 shell can considerably reduce the activation energy of H2 dissociation, while the single Pd atom doped at the top site or in the inner layers is much less effective. The H atom adsorption on Cu55 is slightly stronger than that on the Cu(111) surface; however, a larger nanoparticle that contains 147 atoms could effectively recover the weak binding of the H atoms. We have also investigated the H atom diffusion on the 55-atom nanoparticle and found that spillover of the produced H atoms could be a feasible process due to the low diffusion barriers. Our results have demonstrated that facile H2 dissociation and weak H atom adsorption could be combined at the nanoscale. Moreover, the effects of doping one more Pd atom on the H2 dissociation and H atom adsorption have also been investigated. We have found that both the doping Pd atoms in the most stable configuration could independently exhibit their catalytic activity, behaving as two single-atom-alloy catalysts.
is an invasive pathogen with high morbidity and mortality in the immunocompromised children and elderly. NOD-like receptor family pyrin domain containing 6 (NLRP6) plays an important role in the host ...innate immune response against pathogen infections. Our previous studies have shown that NLRP6 plays a negative regulatory role in host defense against
, but the underlying mechanism is still unclear. The further negative regulatory role of NLRP6 in the host was investigated in this study. Our results showed that NLRP6
mice in the lung had lower bacterial burdens after
infection and expressed higher level of tight junction (TJ) protein occludin compared to WT mice, indicating the detrimental role of NLRP6 in the host defense against
infection. Transcriptome analysis showed that genes related to leukocytes migration and recruitment were differentially expressed between wild-type (WT) and NLRP6 knockout (NLRP6
) mice during
infection. Also, NLRP6
mice showed higher expression of chemokines including C-X-C motif chemokine ligand 1 (CXCL1) and 2 (CXCL2) and lower gene expression of complement C3a receptor 1 (C3aR1) and P-selectin glycoprotein ligand-1 (PSGL-1) which are the factors that inhibit the recruitment of neutrophils. Furthermore, NLRP6
neutrophils showed increased intracellular bactericidal ability and the formation of neutrophil extracellular traps (NETs) during
infection. Taken together, our study suggests that NLRP6 is a negative regulator of neutrophil recruitment and function during
infection. Our study provides a new insight to develop novel strategies to treat invasive pneumococcal infection.
Two-dimensional (2D) crystalline materials have been regarded as promising sensor materials due to their large specific surface area, high sensitivity, and low cost. In the present work, based on the ...density functional theory (DFT) method, the sensor performance of novel silicon (Si)-doped nitrogenated holey graphene (SiC2N) toward five typical VOCs (HCHO, CH3OH, C3H6O, C6H6, and C2HCl3) and ammonia were systematically investigated. The results demonstrated that Si doping could effectively decrease the band gap of C2N and simultaneously provide active sites for gas adsorption. Through comprehensive analyses of adsorption energies and electronic properties, the SiC2N was found to exhibit high selectivity for O-containing VOCs (HCHO, CH3OH, and C3H6O) and NH3 via a covalent bond. Moreover, after the HCHO, CH3OH, C3H6O, and NH3 adsorption, the band gap of SiC2N greatly decreases from 1.07 eV to 0.29, 0.13, 0.25, and 0.12 eV, respectively, which indicated the enhancement the conductivity and enabled the SiC2N to be a highly sensitive resistive-type sensor. In addition, the SiC2N possesses a short recovery time. For instance, the recovery time of HCHO desorbed from SiC2N is 29.2 s at room temperature. Our work anticipates a wide range of potential applications of Si-doped C2N for the detection of toxic VOCs and ammonia, and supplies a valuable reference for the development of C2N-based gas sensors.
There exist a great many varieties of nanoparticles whose catalytic activities can be widely adjusted by changing their composition, shape, and size. Nørskov’s concepts to correlate the d-band ...center, adsorption energy, and activation energy offer an innovative approach to efficiently investigate the catalytic properties. Taking binary noble-metal polyhedral nanoparticles as representative systems, we found from first-principles simulations that the well-established scaling relations of the adsorption energies for extended surfaces can be seamlessly extended to the nanoscale. A systematic investigation of the correlation relations of the adsorption energies between the AH X groups and the corresponding A atoms in the binary noble-metal polyhedral nanoclusters of different compositions, shapes, and sizes clearly demonstrates the linear scaling relation. More remarkably, the scaling relation at the nanoscale can be effectively unified with the well-established scaling relations for extended surfaces. Such a description should be extremely helpful for the efficient screening of nanoparticles with superior catalytic properties.
Abstract The development of accurate and efficient interatomic potentials using machine learning has emerged as an important approach in materials simulations and discovery. However, the systematic ...construction of diverse, converged training sets remains challenging. We develop a deep learning-based interatomic potential for the Li 7 La 3 Zr 2 O 12 (LLZO) system. Our interatomic potential is trained using a diverse dataset obtained from databases and first-principles simulations. We propose using the coverage of the training and test sets as the convergence criteria for the training iterations, where the coverage is calculated by principal component analysis. This results in an accurate LLZO interatomic potential that can describe the structure and dynamical properties of LLZO systems meanwhile greatly reducing computational costs compared to density functional theory calculations. The interatomic potential accurately describes radial distribution functions and thermal expansion coefficient consistent with experiments. It also predicts the tetragonal-to-cubic phase transition behaviors of LLZO systems. Our work provides an efficient training strategy to develop accurate deep-learning interatomic potential for complex solid-state electrolyte materials, providing a promising simulation tool to accelerate solid-state battery design and applications.
The catalytic activity and selectivity of the Pd-doped Cu(111) surface toward the dehydrogenation of propane have been explored by density functional theory calculations with periodic boundary ...conditions. Four models with different Pd ensembles are introduced to represent the Pd/Cu(111) surface, where a surface single-atom catalyst model is built by alloying Cu with Pd. Calculations reveal that the d band center of the surface Pd atom is upshifted with the increased number of Pd atoms, resulting in an enhanced adsorbate–surface bonding strength and a reduced dehydrogenation barrier. The embedded Pd atoms can significantly improve the catalytic reactivity of the pure Cu surface, whereas the presence of the relatively inactive Cu surface is beneficial for the high selectivity toward propylene dehydrogenation. In general, the Pd/Cu(111) surface with the atomically dispersed palladium catalytic centers demonstrates good balance between the activity, selectivity, thermal stability and the maximum use of the noble metal, and shows great potential in the catalytic production of light olefins.
Using cetyltrimethylammonium bromide (CTAB) as the surfactant from the precursors of SnCl2·2H2O, the flower-shaped nano composite of tin oxide (SnO2) is prepared by the simple eco-friendly ...hydrothermal method. We can see that the as-prepared SnO2 sample has a rutile phase crystal structure with regular-shaped nanosheets, and the nanosheets were cross-assembled to form nanoflowers. The band gap of the as-prepared SnO2 sample is 2.26 eV, which is close to the calculated energy gap of 2.58 eV based on density functional theory. The sample is used to degrade the organic dye, and this preliminary application study indicates that the as-prepared SnO2 sample has good stability and reusability in the visible light assisted degradation of methyl orange. Through capture experiments, it is determined that electrons and holes play a major role in the degradation process. The reaction mechanism is also analyzed to indicate the internal relationship between the as-prepared SnO2 samples and its photocatalytic properties.
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