Spatial modeling of epidermal nerve fiber patterns

Peripheral neuropathy is a condition associated with poor nerve functionality. Epidermal nerve fiber (ENF) counts per epidermal surface are dramatically reduced and the two-dimensional (2D) spatial structure of ENFs tends to become more clustered as neuropathy progresses. Therefore, studying the spatial structure of ENFs is essential to fully understand the mechanisms that guide those morphological changes. In this article, we compare ENF patterns of healthy controls and subjects suffering from mild diabetic neuropathy by using suction skin blister specimens obtained from the right foot. Previous analysis of these data has focused on the analysis and modeling of the spatial ENF patterns consisting of the points where the nerves enter the epidermis, base points, and the points where the nerve fibers terminate, end points, projected on a 2D plane, regarding the patterns as realizations of spatial point processes. Here, we include the first branching points, the points where the nerve trees branch for the first time, and model the three-dimensional (3D) patterns consisting of these three types of points. To analyze the patterns, spatial summary statistics are used and a new epidermal active territory that measures the volume in the epidermis that is covered by the individual nerve fibers is constructed. We developed a model for both the 2D and the 3D patterns including the branching points. Also, possible competitive behavior between individual nerves is examined. Our results indicate that changes in the ENFs spatial structure can more easily be detected in the later parts of the ENFs.

Modulation of Donor Alkyl Terminal Chains with the Shifting Branching Point Leads to the Optimized Morphology and Efficient All-Small-Molecule Organic Solar Cells

Terminal group modification is one of the most influential factors for small-molecular donors compared with their polymer counterparts, resulting in an opportunity to optimize the morphology of all-small-molecule organic solar cells (ASM-OSCs). In this article, we report three novel small-molecular donors with branching points at the 1-, 2-, and 3-positions in alkyl terminal chains, called BSCl-C1, BSCl-C2, and BSCl-C3, respectively. Using IDIC-4Cl as the acceptor, the subtle branching position shift achieves a dramatic disparity in photovoltaic parameters, as indicated by the short circuit current (J_sc) changing from 4.9 to 20.1 to 14.2 mA cm^-2 and the fill factor varying from 33.9 to 71.3 to 67.0% for BSCl-C1, BSCl-C2, and BSCl-C3, respectively. The best device performance of 12.40% is obtained by the BSCl-C2:IDIC-4Cl system, which not only ranks among the top values reported to date but also exhibits low energy loss in systems that use IDIC as acceptors. The notable device performance based on BSCl-C2 is attributed to the optimized phase morphology caused by the strong molecular crystallinity and suitable intermolecular interaction with IDIC-4Cl. These results demonstrate that suitably tuning the branching position of terminal groups could promote the high performance of ASM-OSCs.