Fast collective evasion in self-localized swarms of unmanned aerial vehicles.

A novel approach for achieving fast evasion in self-localized swarms of unmanned aerial vehicles (UAVs) threatened by an intruding moving object is presented in this paper. Motivated by natural self-organizing systems, the presented approach of fast and collective evasion enables the UAV swarm to avoid dynamic objects (interferers) that are actively approaching the group. The main objective of the proposed technique is the fast and safe escape of the swarm from an interferer discovered in proximity. This method is inspired by the collective behavior of groups of certain animals, such as schools of fish or flocks of birds. These animals use the limited information of their sensing organs and decentralized control to achieve reliable and effective group motion. The system presented in this paper is intended to execute the safe coordination of UAV swarms with a large number of agents. Similar to natural swarms, this system propagates a fast shock of information about detected interferers throughout the group to achieve dynamic and collective evasion. The proposed system is fully decentralized using only onboard sensors to mutually localize swarm agents and interferers, similar to how animals accomplish this behavior. As a result, the communication structure between swarm agents is not overwhelmed by information about the state (position and velocity) of each individual and it is reliable to communication dropouts. The proposed system and theory were numerically evaluated and verified in real-world experiments.

Unusual Chemistry in an Uncatalyzed Bromate-Aniline Oscillator: Ring-Contraction Oxidation of Aniline with Pulsative CO2 Production.

The bromate-aniline oscillatory reaction was discovered 4 decades ago, but neither the detailed mechanism nor the key products or intermediates of the reaction were described. We report herein a detailed study of this reaction, which yielded new insights. We found that oscillatory oxidation of aniline by acidic bromate proceeds, to a significant extent, via a novel reaction pathway with the periodic release of carbon dioxide. Several products were isolated, and their structures, not described so far, were justified on the basis of MS and NMR. One of the main products of the reaction associated with the CO2 release route can be assigned to 2,2-dibromo-5-(phenylimino)cyclopent-3-en-1-one. A number of known compounds produced in the studied reaction, including unexpected brominated 1-phenylpyrroles and 1-phenylmaleimides, were identified by comparison with standards. A mechanism is suggested to explain the appearance of the detected compounds, based on coupling of the anilino radical with the produced 1,4-benzoquinone. We assume that the radical adduct reacts with bromine to form a cyclopropanone intermediate that undergoes a Favorskii-type rearrangement. Further oxidation and bromination steps including decarboxylation lead to the found brominated phenyliminocyclopentenones. The detected derivatives of 1-phenylpyrrole could be produced by a one-electron oxidation of a proposed intermediate 2-phenylamino-5-bromocyclopenta-1,3-dien-1-ol followed by ß-scission with the abstraction of carbon monoxide. Such a mechanism is known from the combustion chemistry of cyclopentadiene. The proposed mechanism of this reaction provides a framework for understanding the observed oscillatory kinetics.

Metabolism of Scoparone in Experimental Animals and Humans.

Scoparone, a major constituent of the Chinese herbal medicine Yin Chen Hao, expresses beneficial effects in experimental models of various diseases. The intrinsic doses and effects of scoparone are dependent on its metabolism, both in humans and animals. We evaluated in detail the metabolism of scoparone in human, mouse, rat, pig, dog, and rabbit liver microsomes in vitro and in humans in vivo. Oxidation of scoparone to isoscopoletin via 6-O-demethylation was the major metabolic pathway in liver microsomes from humans, mouse, rat, pig and dog, whereas 7-O-demethylation to scopoletin was the main reaction in rabbit. The scoparone oxidation rates in liver microsomes were 0.8 - 1.2 µmol/(min*g protein) in mouse, pig, and rabbit, 0.2 - 0.4 µmol/(min*g protein) in man and dog, and less than 0.1 µmol/(min*g) in rat. In liver microsomes of all species, isoscopoletin was oxidized to 3-[4-methoxy-ρ-(3, 6)-benzoquinone]-2-propenoate and esculetin, which was formed also in the oxidation of scopoletin. Human CYP2A13 exhibited the highest rate of isoscopoletin and scopoletin oxidation, followed by CYP1A1 and CYP1A2. Glucuronidation of isoscopoletin and scopoletin was catalyzed by the human UGT1A1, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, and UGT2B17. Dog was most similar to man in scoparone metabolism. Isoscopoletin glucuronide and sulfate conjugates were the major scoparone in vivo metabolites in humans, and they were completely excreted within 24 h in urine. Scoparone and its metabolites did not activate key nuclear receptors regulating CYP and UGT enzymes. These results outline comprehensively the metabolic pathways of scoparone in man and key preclinical animal species.

The impact of sesquiterpenes ß-caryophyllene oxide and trans-nerolidol on xenobiotic-metabolizing enzymes in mice in vivo.

1. Sesquiterpenes, constituents of plant essential oil, are popular bioactive compounds due to the positive effect on human health, but their potential toxicity and possible herb-drug interactions are often omitted. In our in vivo study, we followed up the effect of p.o. administration of two sesquiterpenes ß-caryophyllene oxide (CAO) and trans-nerolidol (NER) on various xenobiotic-metabolizing enzymes in mice liver and small intestine. 2. To spot the early effect of studied compounds, enzymatic activity and mRNA levels were assessed 6 and 24 h after single dose. 3. CAO and NER markedly increased cytochromes P450 (CYP2B, 3A, 2C) activity and mRNA levels in both tissues. Liver also showed elevated activity of aldo-ketoreductase 1C and carbonyl reductase after treatment. Contrary, sesquiterpenes decreased NAD(P)H:quinone oxidoreductase 1 activity in small intestine. Among conjugation enzymes, only liver sulfotransferase activity was increased by sesquiterpenes. 4. Our results document that single dose of sesquiterpenes modulate activities and expression of several xenobiotic-metabolizing enzymes.

Antiarrhythmic effect of newly synthesized compound 44Bu on model of aconitine-induced arrhythmia -- compared to lidocaine.

The antiarrhythmic action of the newly developed compound 44Bu (an original compound that was synthesized at our Faculty of Pharmacy) was tested on a model of aconitine-induced arrhythmia and compared with the effect of lidocaine. Both tested substances were administered either as therapeutic or prophylactic agents. 44Bu was highly effective in reducing the occurrence of ventricular fibrillation from 94% to 8% by therapeutic administration, and to 0% by prophylactic administration. The overall mortality rate was significantly reduced by 44Bu from 100% to 25% in the case of therapeutic administration, and to 0% in the case of prophylactic administration. In contrast, there was not any significant difference between therapeutic and prophylactic administration of lidocaine. The occurrence of ventricular fibrillation dropped from 94% to 50% with therapeutic administration, and to 67% with prophylactic administration of lidocaine. The overall mortality rate was significantly reduced from 100% to 63% and to 67%, respectively. We conclude that the 44Bu compound is a highly effective agent in suppressing aconitine-induced arrhythmias. The antiarrhythmic effect of 44Bu was significantly more evident in comparison with lidocaine, particularly in the case of its prophylactic administration.

Redox-active silica nanoparticles. Part 1. Electrochemistry and catalytic activity of spherical, nonporous silica particles with nanometric diameters and covalently bound redox-active modifications.

Nonporous spherical silica nanoparticles resulting from a controlled Stöber process are covalently surface modified with redox-active molecules. Ferrocene, a ruthenium(II) complex with an N2P2Cl2 ligand set, and a sterically hindered biphenylamine are used as modifiers. The resulting materials are characterized by physical, spectroscopic, electrochemical, and chemical methods. The cyclic voltammetric behavior is studied in detail and reveals effects of charge transport by electron hopping along the surface of particles adsorbed on a Pt electrode. The ruthenium(II) complex remains catalytically active with respect to hydrogenation upon immobilization on the particles. Thus, the respective material provides a heterogenized homogeneous hydrogenation catalyst on a solid support.

Effect of a new ultrashort betalytic agent on aconitine-induced arrhythmia.

The anti-arrhythmic effect was tested on the model of aconitine-induced arrhythmia. The experiment was performed in vivo with 31 male Wistar laboratory rats. Group A was first administered aconitine and, after the onset of the first sinus rhythm disorders, the 44Bu compound was administered. Group B was first administered the 44Bu compound and only after that the aconitine. The control group was administered aconitine and saline as a replacement of the tested compound. In group A, there was a decrease in the ventricular fibrillation occurrence from 100 % to 8 % (p < 0.001) after the administration of the 44Bu compound. In the B group, the onsets of all monitored arrhythmia types were delayed by an average of 15.6 min. Ventricular rhythm occurrence was decreased from 100 to 20 %, as well as ventricular fibrillations, from 100 to 0 % (p < 0.001).