Gas bubbles of nanometer size were produced on atomically flat solid surfaces and imaged by atomic force microscopy (AFM) in tapping mode in water. In AFM images, nanobubbles appeared like bright spheres. Some of the bubbles remained stable for hours during the experiments. The bubbles were disturbed under high load during AFM imaging. A related mechanism is discussed.

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Abstract. The purpose of this paper is to study the shapes and stabilities of biomembranes within the framework of exterior differential forms. After a brief review of the current status in theoretical and experimental studies on the shapes of biomembranes, a geometric scheme is proposed to discuss the shape equation of closed lipid bilayers, the shape equation and boundary conditions of open lipid bilayers and two-component membranes, the shape equation and in-plane strain equations of cell membranes with cross-linking structures, and the stabilities of closed lipid bilayers and cell membranes. The key point of this scheme is to deal with the variational problems on the surfaces embedded in three-dimensional Euclidean space by using exterior differential forms.

Huntington's disease (HD) is characterized by preferential loss of the medium spiny neurons in the striatum. Using CRISPR/Cas9 and somatic nuclear transfer technology, we established a knockin (KI) pig model of HD that endogenously expresses full-length mutant huntingtin (HTT). By breeding this HD pig model, we have successfully obtained F1 and F2 generation KI pigs. Characterization of founder and F1 KI pigs shows consistent movement, behavioral abnormalities, and early death, which are germline transmittable. More importantly, brains of HD KI pig display striking and selective degeneration of striatal medium spiny neurons. Thus, using a large animal model of HD, we demonstrate for the first time that overt and selective neurodegeneration seen in HD patients can be recapitulated by endogenously expressed mutant proteins in large mammals, a finding that also underscores the importance of using large mammals to investigate the pathogenesis of neurodegenerative diseases and their therapeutics.