Adam Galuszka

Planning in Multi-agent Environment Using Strips Representation and Non-cooperative Equilibrium Strategy

In multi-agent (multi-robot) environment each agent tries to achieve its own goals leading usually to goals conflict. However, there exists a group of problems with conflicting goals, satisfaction of which is possible simultaneously. Such problems can be modelled as a STRIPS system (for instance Block World environment). If STRIPS planning problem is invertible than it is possible to apply planning under uncertainty methodologies to solve inverted problem and then find a plan that solves multi-agent problem. In the paper, a multi-agent Block World environment is presented as an invertible STRIPS problem. Two cases are considered: when goals conflict and do not conflict. A necessary condition of plan existence is formulated. In the case when goals conflict and agents have different goal preferences we show that it is possible to use non-cooperative equilibrium strategy for modification of the plan found previously. This modification guarantees the best solution (in the sense of non-cooperative equilibrium) for all agents in some cases.

Hand landmarks detection and localization in color images

This paper introduces a new method for detecting and localizing hand landmarks in 2D color images. Location of the hand landmarks is an important source of information for recognizing hand gestures, effectively exploited in a number of recent methods which operate from the depth maps. However, this problem has not yet been satisfactorily solved for 2D color images. Here, we propose to analyze the skin-presence masks, as well as the directional image of a hand using the distance transform and template matching. This makes it possible to detect the landmarks located both at the contour and inside the hand masks. Moreover, we performed an extensive experimental study to compare the proposed method with a number of state-of-the-art algorithms. The obtained quantitative and qualitative results clearly indicate that our approach outperforms other methods, which may help improve the existing gesture recognition systems.

Antidepressant- and Anxiolytic-Like Effects of New Dual 5-HT1A and 5-HT7 Antagonists in Animal Models

The aim of this study was to further characterize pharmacological properties of two phenylpiperazine derivatives: 1-{2-[2-(2,6-dimethlphenoxy)ethoxy]ethyl}-4-(2-methoxyphenyl)piperazynine hydrochloride (HBK-14) and 2-[2-(2-chloro-6-methylphenoxy)ethoxy]ethyl-4-(2- methoxyphenyl)piperazynine dihydrochloride (HBK-15) in radioligand binding and functional in vitro assays as well as in vivo models. Antidepressant-like properties were investigated in the forced swim test (FST) in mice and rats. Anxiolytic-like activity was evaluated in the four-plate test in mice and elevated plus maze test (EPM) in rats. Imipramine and escitalopram were used as reference drugs in the FST, and diazepam was used as a standard anxiolytic drug in animal models of anxiety. Our results indicate that HBK-14 and HBK-15 possess high or moderate affinity for serotonergic 5-HT2, adrenergic α1, and dopaminergic D2 receptors as well as being full 5-HT1A and 5-HT7 receptor antagonists. We also present their potent antidepressant-like activity (HBK-14—FST mice: 2.5 and 5 mg/kg; FST rats: 5 mg/kg) and (HBK-15—FST mice: 1.25, 2.5 and 5 mg/kg; FST rats: 1.25 and 2.5 mg/kg). We show that HBK-14 (four-plate test: 2.5 and 5 mg/kg; EPM: 2.5 mg/kg) and HBK-15 (four-plate test: 2.5 and 5 mg/kg; EPM: 5 mg/kg) possess anxiolytic-like properties. Among the two, HBK-15 has stronger antidepressant-like properties, and HBK-14 displays greater anxiolytic-like activity. Lastly, we demonstrate the involvement of serotonergic system, particularly 5-HT1A receptor, in the antidepressant- and anxiolytic-like actions of investigated compounds.

Generalized Backpropagation through Time for Continuous Time Neural Networks and Discrete Time Measurements

This paper deals with the problem of identification of continuous time dynamic neural networks when the measurements are given only at discrete time moments, not necessarily uniformly distributed. It is shown that the modified adjoint system, generating the gradient of the performance index, is a continuous-time system with jumps of state variables at moments corresponding to moments of measurements.

The antidepressant-like activity of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one involves serotonergic 5-HT1A and 5-HT2A/C receptors activation

Xanthone derivatives have been shown to posses many biological properties. Some of them act within the central nervous system and show neuroprotective or antidepressant-like properties. Taking this into account we investigated antidepressant-like activity in mice and the possible mechanism of action of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-11) - a new xanthone derivative. We demonstrated that HBK-11 produced antidepressant-like effects in the forced swim test and tail suspension test, comparable to that of venlafaxine. The combined treatment with sub-effective doses of HBK-11 and fluoxetine (but not reboxetine or bupropion) significantly reduced the immobility in the forced swim test. Moreover, the antidepressant-like activity of HBK-11 in the aforementioned test was blocked by p-chlorophenylalanine, and significantly reduced by serotonergic 5HT1A receptor antagonist - WAY-1006335 and 5HT2A/C receptor antagonist - ritanserin. As none of the above treatments influenced the spontaneous locomotor activity, it can be concluded that HBK-11 mediates its activity through a serotonergic system, and its antidepressant-like effect involves 5HT1A and 5HT2A/C receptor activation. Furthermore, at antidepressant-like doses HBK-11 did not cause the mice to display locomotor deficits in rotarod or chimney tests. Considering the pharmacokinetic profile, HBK-11 demonstrated rapid absorption after i.p. administration, high clearance value, short terminal half-life, very high volume of distribution and incomplete bioavailability. The compound studied had good penetration into the brain tissue of mice. Since studied xanthone derivative seems to present interesting, untypical mechanism of antidepressant-like action i.e. 5HT2A/C receptor activation, it may have a potential in the treatment of depressive disorders, and surely requires further studies.

HBK-7 - A new xanthone derivative and a 5-HT1A receptor antagonist with antidepressant-like properties.

Xanthone derivatives possess many biological properties, including neuroprotective, antioxidant or antidepressant-like. In this study we aimed to investigate antidepressant- and anxiolytic-like properties of a new xanthone derivative - 6-methoxy-4-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-7), as well as its possible mechanism of action, and the influence on cognitive and motor function. HBK-7 in our earlier studies showed high affinity for serotonergic 5-HT1A receptor. We determined the affinity of HBK-7 for CNS receptors and transporters using radioligand assays and examined its intrinsic activity towards 5-HT1A receptor. We evaluated antidepressant- and anxiolytic-like activity of HBK-7 in the mouse forced swim test, and four-plate test, respectively. We examined the influence on locomotor activity in mice to determine if the effect observed in the forced swim test was specific. We used step-through passive avoidance and rotarod tests to evaluate the influence of HBK-7 on cognitive and motor function, respectively. HBK-7 showed moderate affinity for dopaminergic D2 receptor and very low for serotonergic 5-HT2A, adrenergic α2 receptors, as well as serotonin transporter. Functional studies revealed that HBK-7 was a 5-HT1A receptor antagonist. HBK-7 (10mg/kg) decreased immobility time in the forced swim test. Combined treatment with sub-effective doses of HBK-7 and fluoxetine reduced immobility of mice in the forced swim test. Pretreatment with p-chlorophenylalanine and WAY-100,635 antagonized the antidepressant-like effect of HBK-7. Neither of the treatments influenced locomotor activity of mice. HBK-7 at antidepressant-like dose did not impair memory or motor coordination in mice. We demonstrated that HBK-7 was a 5-HT1A receptor antagonist with potent, comparable to mianserin, antidepressant-like activity. HBK-7 mediated its effect through serotonergic system and its antidepressant-like action required the activation of 5-HT1A receptors. At active dose it did not influence cognitive and motor function. Since 5-HT1A receptor antagonists may accelerate the occurrence of antidepressant effect, our findings highlight their potential as future antidepressants.

Chemically Homogenous Compounds with Antagonistic Properties at All α1-Adrenoceptor Subtypes but not β1-Adrenoceptor Attenuate Adrenaline-Induced Arrhythmia in Rats

Studies proved that among all α1-adrenoceptors, cardiac myocytes functionally express only α1A- and α1B-subtype. Scientists indicated that α1A-subtype blockade might be beneficial in restoring normal heart rhythm. Therefore, we aimed to determine the role of α1-adrenoceptors subtypes (i.e., α1A and α1B) in antiarrhythmic effect of six structurally similar derivatives of 2-methoxyphenylpiperazine. We compared the activity of studied compounds with carvedilol, which is β1- and α1-adrenoceptors blocker with antioxidant properties. To evaluate the affinity for adrenergic receptors, we used radioligand methods. We investigated selectivity at α1-adrenoceptors subtypes using functional bioassays. We tested antiarrhythmic activity in adrenaline-induced (20 μg/kg i.v.), calcium chloride-induced (140 and 25 mg/kg i.v.) and barium chloride-induced (32 and 10 mg/kg i.v.) arrhythmia models in rats. We also evaluated the influence of studied compounds on blood pressure in rats, as well as lipid peroxidation. All studied compounds showed high affinity toward α1-adrenoceptors but no affinity for β1 receptors. Biofunctional studies revealed that the tested compounds blocked α1A-stronger than α1B-adrenoceptors, but except for HBK-19 they antagonized α1A-adrenoceptor weaker than α1D-subtype. HBK-19 showed the greatest difference in pA2 values—it blocked α1A-adrenoceptors around seven-fold stronger than α1B subtype. All compounds showed prophylactic antiarrhythmic properties in adrenaline-induced arrhythmia, but only the activity of HBK-16, HBK-17, HBK-18, and HBK-19 (ED50 = 0.18–0.21) was comparable to that of carvedilol (ED50 = 0.36). All compounds reduced mortality in adrenaline-induced arrhythmia. HBK-16, HBK-17, HBK-18, and HBK-19 showed therapeutic antiarrhythmic properties in adrenaline-induced arrhythmia. None of the compounds showed activity in calcium chloride- or barium chloride-induced arrhythmias. HBK-16, HBK-17, HBK-18, and HBK-19 decreased heart rhythm at ED84. All compounds significantly lowered blood pressure in normotensive rats. HBK-18 showed the strongest hypotensive properties (the lowest active dose: 0.01 mg/kg). HBK-19 was the only compound in the group, which did not show hypotensive effect at antiarrhythmic doses. HBK-16, HBK-17, HBK-18, HBK-19 showed weak antioxidant properties. Our results indicate that the studied 2-methoxyphenylpiperazine derivatives that possessed stronger α1A-adrenolytic properties (i.e., HBK-16, HBK-17, HBK-18, and HBK-19) were the most active compounds in adrenaline-induced arrhythmia. Thus, we suggest that the potent blockade of α1A-receptor subtype is essential to attenuate adrenaline-induced arrhythmia.

Translation STRIPS planning in multi-robot environment to linear programming

In the paper multi-robot environment with STRIPS representation is considered. Under some assumptions such problems can be modelled as a STRIPS system (for instance Block World environment) with one initial state and disjunction of goal states. If STRIPS planning problem is invertible then it is possible to apply machinery for planning in the presence of incomplete information to solve the inverted problem and then to find a solution for the original problem. To reduce computational complexity of this approach a transformation to Linear Programming problem is proposed. Simulations illustrate the reduced problem.

Planning as Artificial Intelligence Problem - Short Introduction and Overview

Planning belongs to fundamental AI domains. Examples of planning applications are manufacturing, production planning, logistics and agentics. Over the decades planning techniques were improved and now they are able to capable real environment problems in the presence of uncertain and incomplete information. This article introduces the notion of so called classical planning, indicating connected with this computational complexity problems and possible ways of treating uncertainty.

The antidepressant- and anxiolytic-like activities of new xanthone derivative with piperazine moiety in behavioral tests in mice

Objectives: Xanthones are flavonoids with numerous activities, including antioxidant, antidepressant., or anxiolytic-like. Therefore, the aim of our study was to determine antidepressant- and anxiolytic-like properties of four xanthone derivatives (3-chloro-5-[(4-methylpiperazin-1-yl)methyl]-9H-xanthen-9-one dihydrochloride [HBK-5], 6-methoxy-2-[(4-methylpiperazin-1-yl) methyl]-9H-xanthen-9-one dihydrochloride, 2-[(4-benzylpiperazin-1-yl) methyl]-6-methoxy-9H-xanthen-9-one dihydrochloride, 2-{[4-(2-methoxyphenyl) piperazin-1-yl] methyl}-9H-xanthen-9-one hydrochloride), as well as the influence on cognitive and motor function of active compounds, using animal models. Materials and Methods: To determine the antidepressant-like activity, we used forced swim test (FST) and tail suspension test (TST) in mice. We evaluated anxiolytic-like properties in the four-plate test in mice. We studied the influence on cognitive and motor function in passive avoidance step-through and chimney tests, respectively. Results: The antidepressant-like activity (in both FST and TST) showed only HBK-5. Moreover, the compound was also active in the four-plate test, which suggests that it possessed anxiolytic-like properties. HBK-5 did not cause any cognitive and motor deficits in mice at antidepressant- and anxiolytic-like doses. Conclusions: HBK-5 may have potential in the treatment of depression or anxiety disorders, but this issue needs further studies.