Topological map-based approach for localization and mapping memory optimization

Robotics in agriculture faces several challenges, such as the unstructured characteristics of the environments, variability of luminosity conditions for perception systems, and vast field extensions. To implement autonomous navigation systems in these conditions, robots should be able to operate during large periods and travel long trajectories. For this reason, it is essential that simultaneous localization and mapping algorithms can perform in large-scale and long-term operating conditions. One of the main challenges for these methods is maintaining low memory resources while mapping extensive environments. This work tackles this issue, proposing a localization and mapping approach called VineSLAM that uses a topological mapping architecture to manage the memory resources required by the algorithm. This topological map is a graph-based structure where each node is agnostic to the type of data stored, enabling the creation of a multilayer mapping procedure. Also, a localization algorithm is implemented, which interacts with the topological map to perform access and search operations. Results show that our approach is aligned with the state-of-the-art regarding localization precision, being able to compute the robot pose in long and challenging trajectories in agriculture. In addition, we prove that the topological approach innovates the state-of-the-art memory management. The proposed algorithm requires less memory than the other benchmarked algorithms, and can maintain a constant memory allocation during the entire operation. This consists of a significant innovation, since our approach opens the possibility for the deployment of complex 3D SLAM algorithms in real-world applications without scale restrictions.     

Hydrophobization of hair to improve the interfacial adhesion between hair and high-density polyethylene

Concerned about environmental pollution, and aware of the comfort that polyethylene provides for daily human life, this work sought to replace a percentage of high-density polyethylene (HDPE) with human or bovine hair. Hair is natural, abundant, light weight, non-toxic, and disposed of as garbage. The main disadvantage of natural composites is the interfacial adhesion. To increase the interfacial adhesion between hair and HDPE, stearic acid or oleic acid was chemically anchored on the hair surface, which leads to an improved contact angle hysteresis and hydrophobicity. Dynamic-mechanical properties of the composites were investigated focusing on the type of carboxylic acid used (stearic or oleic acid), hair length, hair type (human or bovine) and amount of hair used in the composite. Taking 40°C as a reference, using 15% of hair with a length of 1 ± 0.15 mm, the highest storage modulus value was obtained with HDPE with human hair modified with oleic acid, exceeding the value of the storage modulus of HDPE by 67.64%. Increasing storage modulus on composites indicates of interfacial interaction and chemical affinity improvement between hair and polyethylene.     

A self-training automatic infant-cry detector

Neural Computing and Applications - Infant cry is one of the first distinctive and informative life signals observed after birth. Neonatologists and automatic assistive systems can analyse infant...     

Optimization of N-Piperidinyl-Benzimidazolone Derivatives as Potent and Selective Inhibitors of 8-Oxo-Guanine DNA Glycosylase 1

8-oxo Guanine DNA Glycosylase 1 is the initiating enzyme within base excision repair and removes oxidized guanines from damaged DNA. Since unrepaired 8-oxoG could lead to G : C→T : A transversion, base removal is of utmost importance for cells to ensure genomic integrity. For cells with elevated levels of reactive oxygen species this dependency is further increased. In the past we and others have validated OGG1 as a target for inhibitors to treat cancer and inflammation. Here, we present the optimization campaign that led to the broadly used tool compound TH5487. Based on results from a small molecule screening campaign, we performed hit to lead expansion and arrived at potent and selective substituted N-piperidinyl-benzimidazolones. Using X-ray crystallography data, we describe the surprising binding mode of the most potent member of the class, TH8535. Here, the N-Piperidinyl-linker adopts a chair instead of a boat conformation which was found for weaker analogues. We further demonstrate cellular target engagement and efficacy of TH8535 against a number of cancer cell lines.     

Amine‐Catalyzed Asymmetric Epoxidation of α,β‐Unsaturated Aldehydes

The direct organocatalytic enantioselective epoxidation of α,β‐unsaturated aldehydes with different peroxides is presented. Proline, chiral pyrrolidine derivatives, and amino acid‐derived imidazolidinones catalyze the asymmetric epoxidation of α,β‐unsaturated aldehydes. In particular, protected commercially available α,α‐diphenyl‐ and α,α‐di(β‐naphthyl)‐2‐prolinols catalyze the asymmetric epoxidation reactions of α,β‐unsaturated aldehydes with high diastereo‐ and enantioselectivities to furnish the corresponding 2‐epoxy aldehydes in high yield with up to 97:3 dr and 98 % ee. The use of non‐toxic catalysts, water and hydrogen peroxide, urea hydroperoxide or sodium percarbonate as the oxygen sources could make this reaction environmentally benign. In addition, one‐pot direct organocatalytic asymmetric tandem epoxidation‐Wittig reactions are described. The reactions were highly diastereo‐ and enantioselective and provide a rapid access to 2,4‐diepoxy aldehydes. Moreover, a highly stereoselective one‐pot organocatalytic asymmetric cascade epoxidation‐Mannich reaction, which proceeds via the combination of iminium and enamine activation, is presented. The mechanism and stereochemistry of the amino acid‐ and chiral pyrrolidine‐catalyzed direct asymmetric epoxidation of α,β‐unsaturated aldehydes are also discussed.