Human keypoint detection for close proximity human-robot interaction

We study the performance of state-of-the-art human keypoint detectors in the context of close proximity human-robot interaction. The detection in this scenario is specific in that only a subset of body parts such as hands and torso are in the field of view. In particular, (i) we survey existing datasets with human pose annotation from the perspective of close proximity images and prepare and make publicly available a new Human in Close Proximity (HiCP) dataset; (ii) we quantitatively and qualitatively compare state-of-the-art human whole-body 2D keypoint detection methods (OpenPose, MMPose, AlphaPose, Detectron2) on this dataset; (iii) since accurate detection of hands and fingers is critical in applications with handovers, we evaluate the performance of the MediaPipe hand detector; (iv) we deploy the algorithms on a humanoid robot with an RGB-D camera on its head and evaluate the performance in 3D human keypoint detection. A motion capture system is used as reference. The best performing whole-body keypoint detectors in close proximity were MMPose and AlphaPose, but both had difficulty with finger detection. Thus, we propose a combination of MMPose or AlphaPose for the body and MediaPipe for the hands in a single framework providing the most accurate and robust detection. We also analyse the failure modes of individual detectors -- for example, to what extent the absence of the head of the person in the image degrades performance. Finally, we demonstrate the framework in a scenario where a humanoid robot interacting with a person uses the detected 3D keypoints for whole-body avoidance maneuvers.Comment: 8 pages 8 figure

Highly diastereo and enantioselective synthesis of α-spiro-δ-lactams via organocascade reaction

An asymmetric synthesis of α-spiro-δ-lactam via organocascade reaction from easily accessible starting materials is reported. The catalytic sequence undergoes enantioselective Michael addition of β-ketoamide to α,β-unsaturated aldehyde catalysed by a secondary amine catalyst, followed by hemiaminal annulation. Optically enantiopure compounds with two contiguous stereogenic centres are obtained in good yields and excellent selectivities (up to >20:1 dr and up to >99% ee)

Stereoselective Cyclopropanation of Boron Dipyrromethene (BODIPY) derivatives by an organocascade reaction

The synthesis of enantiopure chiral boron dipyrromethenes (BODIPYs) is of importance due the intrinsic properties of BODIPYs as fluorophores that could be used as probes for molecular sensing. The present study reports an asymmetric organocatalytic cascade reaction of meso-chloromethyl BODIPY derivatives with α,β-unsaturated aldehydes catalyzed by a chiral secondary amine. The corresponding BODIPY-derived cyclopropanes were produced in isolated yields 66–98%, and with diastereomeric ratios 3/2->20/1, and 92–99% ee for major diastereomer. The synthetic utility of the protocol was exemplified on a set of additional transformations of the corresponding optically pure compounds. In addition, a study explaining the reaction mechanism (DFT computations) and photophysical characterization of all enantioenriched products were accomplished

Molecular basis of the 14-3-3 protein-dependent activation of yeast neutral trehalase Nth1

The 14-3-3 proteins, a family of highly conserved scaffolding proteins ubiquitously expressed in all eukaryotic cells, interact with and regulate the function of several hundreds of partner proteins. Yeast neutral trehalases (Nth), enzymes responsible for the hydrolysis of trehalose to glucose, compared with trehalases from other organisms, possess distinct structure and regulation involving phosphorylation at multiple sites followed by binding to the 14-3-3 protein. Here we report the crystal structures of yeast Nth1 and its complex with Bmh1 (yeast 14-3-3 isoform), which, together with mutational and fluorescence studies, indicate that the binding of Nth1 by 14-3-3 triggers Nth1's activity by enabling the proper 3D configuration of Nth1's catalytic and calcium-binding domains relative to each other, thus stabilizing the flexible part of the active site required for catalysis. The presented structure of the Bmh1:Nth1 complex highlights the ability of 14-3-3 to modulate the structure of a multidomain binding partner and to function as an allosteric effector. Furthermore, comparison of the Bmh1:Nth1 complex structure with those of 14-3-3:serotonin N-acetyltransferase and 14-3-3:heat shock protein beta-6 complexes revealed similarities in the 3D structures of bound partner proteins, suggesting the highly conserved nature of 14-3-3 affects the structures of many client proteins