Towards Intuitive HMI for UAV Control

In the last decade, UAVs have become a widely used technology. As they are used by both professionals and amateurs, there is a need to explore different control modalities to make control intuitive and easier, especially for new users. In this work, we compared the most widely used joystick control with a custom human pose control. We used human pose estimation and arm movements to send UAV commands in the same way that operators use their fingers to send joystick commands. Experiments were conducted in a simulation environment with first-person visual feedback. Participants had to traverse the same maze with joystick and human pose control. Participants' subjective experience was assessed using the raw NASA Task Load Index.Comment: 2022 International Conference on Smart Systems and Technologies (SST

Towards Instance Segmentation-Based Litter Collection with Multi-Rotor Aerial Vehicle

This paper presents a novel aerial robotics application of instance segmentation-based floating litter collection with a multi-rotor aerial vehicle (MRAV). In the scope of the paper, we present a review of the available datasets for litter detection and segmentation. The reviewed datasets are used to train a Mask-RCNN neural network for instance segmentation. The neural network is off-board deployed on an edge computing device and used for litter position estimation. Based on the estimated litter position, we plan a path based on a quadratic Bezier curve for the litter pickup. We compare different trajectory generation methods for the object pickup. The system is verified in a laboratory environment. Eventually, we present practical considerations and improvements necessary to enable autonomous litter collection with MRAV

A membrane-bound esterase PA2949 from Pseudomonas aeruginosa is expressed and purified from Escherichia coli

Pseudomonas aeruginosa strain 1001 produces an esterase (EstA) that can hydrolyse the racemic methyl ester of b-acetylthioisobutyrate to produce the (D)-enantiomer, which serves as a precursor of captopril, a drug used for treatment of hypertension. We show here that PA2949 from P. aeruginosa PA01, a homologue of EstA, can efficiently be expressed in an enzymatically active form in E. coli. The enzyme is membrane-associated as demonstrated by cell fractionation studies. PA2949 was purified to homogeneity after solubilisation with the nonionic detergent, Triton X-100, and was shown to possess a conserved esterase catalytic triad consisting of Ser137–His258–Asp286. Our results should allow the development of an expression and purification strategy to produce this biotechnologically relevant esterase in a pure form with a high yield

Novel insights into biosynthesis and uptake of rhamnolipids and their precursors

The human pathogenic bacterium Pseudomonasaeruginosa produces rhamnolipids, glycolipids with functionsfor bacterial motility, biofilm formation, and uptake of hydrophobicsubstrates. Rhamnolipids represent a chemically heterogeneousgroup of secondary metabolites composed of one ortwo rhamnose molecules linked to one or mostly two 3-hydroxyfatty acids of various chain lengths. The biosyntheticpathway involves rhamnosyltransferase I encoded by the rhlABoperon, which synthesizes 3-(3-hydroxyalkanoyloxy)alkanoicacids (HAAs) followed by their coupling to one rhamnose moiety.The resulting mono-rhamnolipids are converted to dirhamnolipidsin a third reaction catalyzed by therhamnosyltransferase II RhlC. However, the mechanism behindthe biosynthesis of rhamnolipids containing only a singlefatty acid is still unknown. To understand the role of proteinsinvolved in rhamnolipid biosynthesis the heterologous expressionof rhl-genes in non-pathogenic Pseudomonas putidaKT2440 strains was used in this study to circumvent the complexquorum sensing regulation in P. aeruginosa. Our resultsreveal that RhlA and RhlB are independently involved inrhamnolipid biosynthesis and not in the form of a RhlAB heterodimercomplex as it has been previously postulated.Furthermore, we demonstrate that mono-rhamnolipids providedextracellularly as well as HAAs as their precursors are generallytaken up into the cell and are subsequently converted todi-rhamnolipids by P. putida and the native host P. aeruginosa.Finally, our results throw light on the biosynthesis ofrhamnolipids containing one fatty acid,which occurs by hydrolyzationof typical rhamnolipids containing two fatty acids,valuable for the production of designer rhamnolipids with desiredphysicochemical properties

Implications of Below-Ground Allelopathic Interactions of Camelina sativa and Microorganisms for Phosphate Availability and Habitat Maintenance

Toxic breakdown products of young Camelina sativa (L.) Crantz, glucosinolates can eliminate microorganisms in the soil. Since microorganisms are essential for phosphate cycling, only insensitive microorganisms with phosphate-solubilizing activity can improve C. sativa’s phosphate supply. In this study, 33P-labeled phosphate, inductively coupled plasma mass spectrometry and pot experiments unveiled that not only Trichoderma viride and Pseudomonas laurentiana used as phosphate-solubilizing inoculants, but also intrinsic soil microorganisms, including Penicillium aurantiogriseum, and the assemblies of root-colonizing microorganisms solubilized as well phosphate from apatite, trigger off competitive behavior between the organisms. Driving factors in the competitiveness are plant and microbial secondary metabolites, while glucosinolates of Camelina and their breakdown products are regarded as key compounds that inhibit the pathogen P. aurantiogriseum, but also seem to impede root colonization of T. viride. On the other hand, fungal diketopiperazine combined with glucosinolates is fatal to Camelina. The results may contribute to explain the contradictory effects of phosphate-solubilizing microorganisms when used as biofertilizers. Further studies will elucidate impacts of released secondary metabolites on coexisting microorganisms and plants under different environmental conditions

The Metagenome-Derived Enzymes LipS and LipT Increase the Diversity of Known Lipases

Triacylglycerol lipases (EC 3.1.1.3) catalyze both hydrolysis and synthesis reactions with a broad spectrum of substrates rendering them especially suitable for many biotechnological applications. Most lipases used today originate from mesophilic organisms and are susceptible to thermal denaturation whereas only few possess high thermotolerance. Here, we report on the identification and characterization of two novel thermostable bacterial lipases identified by functional metagenomic screenings. Metagenomic libraries were constructed from enrichment cultures maintained at 65 to 75°C and screened resulting in the identification of initially 10 clones with lipolytic activities. Subsequently, two ORFs were identified encoding lipases, LipS and LipT. Comparative sequence analyses suggested that both enzymes are members of novel lipase families. LipS is a 30.2 kDa protein and revealed a half-life of 48 h at 70°C. The lipT gene encoded for a multimeric enzyme with a half-life of 3 h at 70°C. LipS had an optimum temperature at 70°C and LipT at 75°C. Both enzymes catalyzed hydrolysis of long-chain (C12 and C14) fatty acid esters and additionally hydrolyzed a number of industry-relevant substrates. LipS was highly specific for (R)-ibuprofen-phenyl ester with an enantiomeric excess (ee) of 99%. Furthermore, LipS was able to synthesize 1-propyl laurate and 1-tetradecyl myristate at 70°C with rates similar to those of the lipase CalB from Candida antarctica. LipS represents the first example of a thermostable metagenome-derived lipase with significant synthesis activities. Its X-ray structure was solved with a resolution of 1.99 Å revealing an unusually compact lid structure

The Effects of Cocaine on Different Redox Forms of Cysteine and Homocysteine, and on Labile, Reduced Sulfur in the Rat Plasma Following Active versus Passive Drug Injections

Received: 28 November 2012 / Revised: 19 April 2013 / Accepted: 6 May 2013 / Published online: 16 May 2013 The Author(s) 2013. This article is published with open access at Springerlink.comThe aim of the present studies was to evaluate cocaine-induced changes in the concentrations of different redox forms of cysteine (Cys) and homocysteine (Hcy), and products of anaerobic Cys metabolism, i.e., labile, reduced sulfur (LS) in the rat plasma. The above-mentioned parameters were determined after i.p. acute and subchronic cocaine treatment as well as following i.v. cocaine self-administration using the yoked procedure. Additionally, Cys, Hcy, and LS levels were measured during the 10-day extinction training in rats that underwent i.v. cocaine administration. Acute i.p. cocaine treatment increased the total and protein-bound Hcy contents, decreased LS, and did not change the concentrations of Cys fractions in the rat plasma. In turn, subchronic i.p. cocaine administration significantly increased free Hcy and lowered the total and protein-bound Cys concentrations while LS level was unchanged. Cocaine self-administration enhanced the total and protein-bound Hcy levels, decreased LS content, and did not affect the Cys fractions. On the other hand, yoked cocaine infusions did not alter the concentration of Hcy fractions while decreased the total and protein-bound Cys and LS content. This extinction training resulted in the lack of changes in the examined parameters in rats with a history of cocaine self-administration while in the yoked cocaine group an increase in the plasma free Cys fraction and LS was seen. Our results demonstrate for the first time that cocaine does evoke significant changes in homeostasis of thiol amino acids Cys and Hcy, and in some products of anaerobic Cys metabolism, which are dependent on the way of cocaine administration