Analytic perturbation solution to the capacitance system of a hyberboloidal tip and a rough surface

The capacitance system of a hyperboloidal tip and a rough surface is usually encountered in analyzing electrostatic force microscopy images. In this letter, a perturbation approach has been applied to solve for the electric potential of this system, in which the rough surface is treated as perturbation from a flat one. For the first-variation solution, the boundary value problem is represented in the prolate-spheroidal coordinate system and solved in terms of a generalized Fourier series involving conical functions. Based on this solution, the tip-surface Coulombic interaction can be computed. Sample calculations have been applied to sinusoidal surface profilesPeer ReviewedPostprint (published version

A Neurotrophic Mechanism Directs Sensory Nerve Transit in Cranial Bone

The flat bones of the skull are densely innervated during development, but little is known regarding their role during repair. We describe a neurotrophic mechanism that directs sensory nerve transit in the mouse calvaria. Patent cranial suture mesenchyme represents an NGF (nerve growth factor)-rich domain, in which sensory nerves transit. Experimental calvarial injury upregulates Ngf in an IL-1 beta/TNF-alpha-rich defect niche, with consequent axonal ingrowth. In calvarial osteoblasts, IL-1 beta and TNF-alpha stimulate Ngf and downstream NF-kappa B signaling. Locoregional deletion of Ngf delays defect site re-innervation and blunted repair. Genetic disruption of Ngf among LysM-expressing macrophages phenocopies these observations, whereas conditional knockout of Ngf among Pdgfra-expressing cells does not. Finally, inhibition of TrkA catalytic activity similarly delays re-innervation and repair. These results demonstrate an essential role of NGF-TrkA signaling in bone healing and implicate macrophage-derived NGF-induced ingrowth of skeletal sensory nerves as an important mediator of this repair

Lysosomal protein surface expression discriminates fat- from bone-forming human mesenchymal precursor cells

Tissue resident mesenchymal stem/stromal cells (MSCs) occupy perivascular spaces. Profiling human adipose perivascular mesenchyme with antibody arrays identified 16 novel surface antigens, including endolysosomal protein CD107a. Surface CD107a expression segregates MSCs into functionally distinct subsets. In culture, CD107a(low) cells demonstrate high colony formation, osteoprogenitor cell frequency, and osteogenic potential. Conversely, CD107a(high) cells include almost exclusively adipocyte progenitor cells. Accordingly, human CD107a(low) cells drove dramatic bone formation after intramuscular transplantation in mice, and induced spine fusion in rats, whereas CD107a(high) cells did not. CD107a protein trafficking to the cell surface is associated with exocytosis during early adipogenic differentiation. RNA sequencing also suggested that CD107a(low) cells are precursors of CD107a(high) cells. These results document the molecular and functional diversity of perivascular regenerative cells, and show that relocation to cell surface of a lysosomal protein marks the transition from osteo- to adipogenic potential in native human MSCs, a population of substantial therapeutic interest

Transcriptomic Analysis of Aedes aegypti Innate Immune System in Response to Ingestion of Chikungunya Virus

Aedes aegypti (L.) is the primary vector of emergent mosquito-borne viruses, including chikungunya, dengue, yellow fever, and Zika viruses. To understand how these viruses interact with their mosquito vectors, an analysis of the innate immune system response was conducted. The innate immune system is a conserved evolutionary defense strategy and is the dominant immune system response found in invertebrates and vertebrates, as well as plants. RNA-sequencing analysis was performed to compare target transcriptomes of two Florida Ae. aegypti strains in response to chikungunya virus infection. We analyzed a strain collected from a field population in Key West, Florida, and a laboratory strain originating from Orlando. A total of 1835 transcripts were significantly expressed at different levels between the two Florida strains of Ae. aegypti. Gene Ontology analysis placed these genes into 12 categories of biological processes, including 856 transcripts (up/down regulated) with more than 1.8-fold (p-adj (p-adjust value) ≤ 0.01). Transcriptomic analysis and q-PCR data indicated that the members of the AaeCECH genes are important for chikungunya infection response in Ae. aegypti. These immune-related enzymes that the chikungunya virus infection induces may inform molecular-based strategies for interruption of arbovirus transmission by mosquitoes