ABSTRACT
Modern spatial transcriptomics methods can target thousands of different types of RNA transcripts in a single slice of tissue. Many biological applications demand a high spatial density of transcripts relative to the imaging resolution, leading to partial mixing of transcript rolonies in many voxels; unfortunately, current analysis methods do not perform robustly in this highly-mixed setting. Here we develop a new analysis approach, BARcode DEmixing through Non-negative Spatial Regression (BarDensr): we start with a generative model of the physical process that leads to the observed image data and then apply sparse convex optimization methods to estimate the underlying (demixed) rolony densities. We apply BarDensr to simulated and real data and find that it achieves state of the art signal recovery, particularly in densely-labeled regions or data with low spatial resolution. Finally, BarDensr is fast and parallelizable. We provide open-source code as well as an implementation for the 'NeuroCAAS' cloud platform.
Subject(s)
Spatial Regression , Algorithms , Computer Simulation , TranscriptomeABSTRACT
BACKGROUND: Tension band wiring and plate fixation are common techniques used to stabilize simple olecranon fractures and osteotomies of the olecranon. All suture fixation is an alternative technique but has not been compared previously to these traditional methods. The aim of this study was to compare the clinical and radiographic outcomes of the three techniques. METHODS: One hundred and sixty-eight consecutive Mayo type 1 and 2 olecranon fractures (n = 138) and olecranon osteotomies (n = 30) with a minimum follow-up time of one year were compared. The primary outcome measure was the rate of re-operation. Secondary outcome measures were the incidence of complications, rate of radiographic union and incidence of radiographic reduction loss. RESULTS: Fixation was performed using tension band wiring in 89 patients, plating in 38 patients and suture fixation in 41 patients. There was no significant difference in the fracture type according to the Mayo classification between the groups. The re-operation rate was significantly higher in the tension band wiring group (36%) compared with both the plate group (11%, p = 0.03) and the suture group (2%, p = 0.002). There were two revision fixations in the tension band wiring group and one in the suture group. There was one asymptomatic non-union in the suture group. All other fractures and osteotomies achieved radiographic union. CONCLUSION: Suture fixation of simple olecranon fractures and osteotomies was reliable in providing stable union and had a significantly lower re-operation rate when compared with tension band wiring.
ABSTRACT
Johnston's organ is the largest mechanosensory organ in Drosophila; it analyzes movements of the antenna due to sound, wind, gravity, and touch. Different Johnston's organ neurons (JONs) encode distinct stimulus features. Certain JONs respond in a sustained manner to steady displacements, and these JONs subdivide into opponent populations that prefer push or pull displacements. Here, we describe neurons in the brain (aPN3 neurons) that combine excitation and inhibition from push/pull JONs in different ratios. Consequently, different aPN3 neurons are sensitive to movement in different parts of the antenna's range, at different frequencies, or at different amplitude modulation rates. We use a model to show how the tuning of aPN3 neurons can arise from rectification and temporal filtering in JONs, followed by mixing of JON signals in different proportions. These results illustrate how several canonical neural circuit components-rectification, opponency, and filtering-can combine to produce selectivity for complex stimulus features.
