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Ludwig, F.

Publications and source records attributed to Ludwig, F..

3 recordsLinked to original sources

Predicting resprouting of Platanus x hispanica following branch pruning by means of machine learning

O_LIResprouting is a crucial survival strategy following the loss of branches, being it by natural events or artificially by pruning. The prediction of resprouting patterns on a physiological basis is a highly complex approach. However, trained gardeners try to predict a trees resprouting after pruning purely based on their empirical knowledge and a visual check of the trees geometry. In this study, we explore in how far such predictions can also be made by algorithms, especially using machine learning. C_LIO_LITable-topped annually pruned Platanus x hispanica trees at a nursery were documented with terrestrial LiDAR scanners in two consecutive years. Topological structures for these trees were abstracted from point clouds by cylinder fitting. Then, new shoots and trimmed branches were labelled on corresponding cylinders. Binary and multiclass classification models were tested for predicting the location and number of new sprouts. C_LIO_LIThe accuracy for predicting whether having or not new shoots on each cylinder reaches 90.8% with the LGBMClassifier, the balanced accuracy is 80.3%. The accuracy for predicting the exact numbers of new shoots with GaussianNB model is 82.1% but its balanced accuracy is reduced to 42.9%. C_LIO_LIThe results were validated with a separate evaluation dataset. It proves a feasibility in predicting resprouting patterns after pruning using this approach. Different tree species, tree forms, and other variables should be addressed in further research. C_LI

plant biology↗

Cooperative dynamics of DNA grafted magnetic nanoparticles optimize magnetic biosensing and coupling to DNA origami

Magnetic nanoparticles (MNPs) enable unique capabilities for biosensing and actuation via coupling to DNA origami, yet how DNA grafting density affects their dynamics and accessibility remains poorly understood. Here, we demonstrate functionalization of MNPs with single-stranded DNA (ssDNA) via click chemistry conjugation with tunable grafting density. Several complementary methods show that particle translational and rotational dynamics exhibit a sigmoidal dependence on ssDNA grafting density. At low densities ssDNA strands are coiled and cause small changes to particle dynamics, while at high densities they form polymer brushes that cooperatively change particle dynamics. Intermediate ssDNA densities show the highest magnetic biosensing sensitivity for detection of target nucleic acids. Finally, we demonstrate that MNPs with high grafting densities are required to efficiently couple them to DNA origami. These results together establish ssDNA grafting density as a critical parameter for functionalization of MNPs for use in a broad range of applications.

biochemistry↗

Locomotion induced by medial septal glutamatergic neurons is linked to intrinsically generated persistent firing

The medial septum and diagonal band of Broca (MSDB) serve as a central hub in an ascending brainstem pathway that conveys sensory and motor signals to the limbic system. However, the cellular and circuit mechanisms underlying these functions remain unclear. Here, we show that transient optogenetic activation of MSDB VGluT2 neurons initiates a structured arousal sequence - beginning with facial movements, followed by pupil dilation and locomotion. Neuropixels recordings reveal persistent MSDB neuronal activity that strongly correlates with arousal-related behaviors. We demonstrate that persistent firing (PF) is an intrinsic property of a subset of MSDB neurons, independent of ongoing synaptic input. PF neurons and putative GABAergic theta-bursting neurons predicted movement initiation, with population activity scaling with initiation magnitude, unlike other MSDB populations. These findings identify PF in the MSDB as a central neural mechanism that orchestrates the transition from preparatory movements to full behavioral engagement, bridging sensory input with locomotor arousal and supporting state transitions within the limbic system.

neuroscience↗