Bellybutton: accessible and customizable deep-learning image segmentation.

The conversion of raw images into quantifiable data can be a major hurdle and time-sink in experimental research, and typically involves identifying region(s) of interest, a process known as segmentation. Machine learning tools for image segmentation are often specific to a set of tasks, such as tracking cells, or require substantial compute or coding knowledge to train and use. Here we introduce an easy-to-use (no coding required), image segmentation method, using a 15-layer convolutional neural network that can be trained on a laptop: Bellybutton. The algorithm trains on user-provided segmentation of example images, but, as we show, just one or even a sub-selection of one training image can be sufficient in some cases. We detail the machine learning method and give three use cases where Bellybutton correctly segments images despite substantial lighting, shape, size, focus, and/or structure variation across the regions(s) of interest. Instructions for easy download and use, with further details and the datasets used in this paper are available at pypi.org/project/Bellybuttonseg .

Role of Molecular Layering in the Enhanced Mechanical Properties of Stable Glasses.

The density, degree of molecular orientation, and molecular layering of vapor-deposited stable glasses (SGs) vary with substrate temperature (Tdep) below the glass-transition temperature (Tg). Density and orientation have been suggested to be factors influencing the mechanical properties of SGs. We perform nanoindentation on two molecules which differ by only a single substituent, allowing one molecule to adopt an in-plane orientation at low Tdep. The reduced elastic modulus and hardness of both molecules show similar Tdep dependences, with enhancements of 15-20% in reduced modulus and 30-45% in hardness at Tdep ≈ 0.8Tg, where the density of vapor-deposited films is enhanced by ∼1.4% compared to that of the liquid-quenched glass. At Tdep < 0.8Tg, one of the molecules produces highly unstable glasses with in-plane orientation. However, both systems show enhanced mechanics. Both the modulus and hardness correlate with the degree of layering, which is similar in both systems despite their variable stability. We suggest that nanoindentation performed normal to the film's surface is influenced by the tighter packing of the molecules in this direction.