Sequential growth and etching of Au nanoparticles in solution are observed in situ using the graphene liquid cell electron microscopy. Observation reveals that concentration of etching ions in aqueous growth solution leads transition from nanoparticle growth to its etching. At each step, the authors demonstrate different kinetics for both morphological evolutions and reaction rates. This study will likely benefit design strategies of nanoparticles with specific size or shape.

Mushroom-shaped phase change memory (PCM) consisting of a Cr/In(3)Sb(1)Te(2) (IST)/TiN (bottom electrode) nanoarray was fabricated via block copolymer lithography and single-step dry etching with a gas mixture of Ar/Cl(2). The process was performed on a high performance transparent glass-fabric reinforced composite film (GFR Hybrimer) suitable for use as a novel substrate for flexible devices. The use of GFR Hybrimer with low thermal expansion and flat surfaces enabled successful nanoscale patterning of functional phase change materials on flexible substrates. Block copolymer lithography employing asymmetrical block copolymer blends with hexagonal cylindrical self-assembled morphologies resulted in the creation of hexagonal nanoscale PCM cell arrays with an areal density of approximately 176 Gb/in(2).

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This paper proposes a novel method for the automatic quantification of amyloid positron emission tomography (PET) using the deep learning (DL)-based spatial normalization (SN) of PET images, which does not require magnetic resonance imaging (MRI) or computed tomography images of the same patient.The accuracy of the method was evaluated for three different amyloid PET radiotracers compared to MRIparcellation-based PET quantification using FreeSurfer. Methods:A deep neural network model used for the SN of amyloid PET images was trained using 994 multicenter amyloid PET images (367 18 F-Flutemetamol and 627 18 F-Florbetaben) and the corresponding 3D MRIs of patients with Alzheimer's disease or mild cognitive impairment, and cognitively normal subjects. For comparison, PET SN was also conducted using the SPM12 program (SPM-based SN). The accuracy of DL-and SPM-based SN and standardized uptake value ratio (SUVR) quantification relative to the FreeSurfer-based estimation in individual brain spaces was evaluated using 148 other amyloid PET images (64 18 F-Flutemetamol and 84 18 F-Florbetaben). Additional external validation was performed using an unseen independent external dataset (30 18 F-Flutemetamol, 67 18 F-Florbetaben, and 39 18 F-Florbetapir).Results: Quantification results using the proposed DL-based method showed stronger correlations with the FreeSurfer estimates than SPM-based SN using MRI did. For example, the slope, y-intercept and R 2 values between SPM and FreeSurfer for the global cortex were 0.869, 0.113, and 0.946, respectively. In contrast, the slope, y-intercept, and R 2 values between the proposed DL-based method and FreeSurfer were 1.019, -0.016, and 0.986, respectively. The external validation study also demonstrated better performance of the proposed method without MR images than that of SPM with MRI. In most brain regions, the proposed method outperformed the SPM SN in terms of linear regression parameters and intraclass correlation coefficients. Conclusion:We evaluated a novel DL-based SN method, which allows quantitative analysis of amyloid 4 brain PET images without structural MRI. The quantification results using the proposed method showed a strong correlation with MRI-parcellation-based quantification using FreeSurfer for all clinical amyloid radiotracers. Therefore, the proposed method will be useful for investigating Alzheimer's disease and related brain disorders using amyloid PET scans.

Gold Nanocrystals Direct observation for growth and etching of colloidal nanocrystals will likely benefit rational design of specific nanoparticles. In this study, the graphene liquid cell electron microscopy not only provides the environment for growth and oxidative etching of colloidal gold nanocrystals, but also proves whole process from growth to etching. Direct observation demonstrates different kinetics at each step. More details can be found in article number http://doi.wiley.com/10.1002/pssa.201800949 by Sang Yun Kim, Jong Min Yuk, and co‐workers.