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We present a diakoptic approach to analysis of microwave transmission lines. The approach is based on the equivalence theorem. Presented results show that the diakoptic approach is much faster than the simultaneous analysis of the whole system. The proposed diakoptic approach decomposes the problem into smaller problems that can be independently solved, which makes this approach suitable for implementation on parallel processors.

This paper presents the results for three different antenna optimization problems that are found using the particle swarm optimizer (PSO). The outcomes found with PSO are compared to the outcomes found with other optimization algorithms to estimate the efficiency of PSO. The first problem is finding the optimal position of the feeding probe in a radiating rectangular waveguide. The second problem is finding the maximal forward gain of a Yagi antenna. The third problem is finding the optimal feeding of a broadside antenna array. The optimization problems have 2, 6, and 20 optimization variables respectively

We compared two optimization algorithms for finding the Pareto front of the one-antenna optimization problem. The first applied algorithm is nondominated sorting genetic algorithm (NSGA) that has proved itself over other variants of GA for finding the Pareto front by the mean of effectiveness. The second applied algorithm is the multiminima optimization algorithm based on the estimation of local minima (ELM), which has been restarted for different weighting factors used for forming the single cost-function. The comparison between these two algorithms is done in the sense of the total number of iterations (EM solver runs) needed for finding a good estimation of the Pareto front. The goal was to find the Pareto front in the optimization of a Yagi antenna for the highest possible forward gain and lowest reflection coefficient in the frequency range 295-305 MHz.

Benzodiazepines are well established as inhibitory modulators of memory processing. This effect is especially prominent when applied before the acquisition phase of a memory task. This minireview concentrates on the putative subtype selectivity of the acquisition-impairing action of benzodiazepines. Namely, recent genetic studies. and standard behavioral tests employing subtype-selective ligands pointed to the predominant involvement of two subtypes of benzodiazepine binding sites in memory modulation. Explicit memory learning seems to be affected through the GABA A receptors containing the α 1 and α 5 subunits, whereas the effects on procedural memory can be mainly mediated by the α 1 subunit. The pervading involvement of the α 1 subunit in memory modulation is not at all unexpected because this subunit is the major subtype, present in 60% of all GABA A receptors. On the other hand, the role of α 5 subunits, mainly expressed in the hippocampus, in modulating distinct forms of memory gives promise of selective pharmacological coping with certain memory deficit states.

The pharmacological approach, using subtype selective ligands, complements genetic studies on the specific contribution of individual receptor subtypes to the various effects of benzodiazepines.The aim of this study was to examine the relative significance of alpha1-containing GABA(A) receptors in the effects of modulators at the benzodiazepine site on anxiety and memory processes.We tested the effects of the nonselective antagonist flumazenil, the preferential alpha1-subunit selective antagonist beta-carboline-3-carboxylate-t-butyl ester (beta-CCt), the nonselective agonist midazolam, the preferential alpha1-subunit selective agonist zolpidem, and the nonselective inverse agonist methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) in a two-way active avoidance task in rats. The influence of flumazenil (10.0 mg/kg) and beta-CCt (30.0 mg/kg) on the effects of the two agonists were also examined. In the schedule 2 x 30 trials, drugs were administered i.p. 20 min before the training session. Avoidance responses in the training session are an anxiety-mediated behavior, whereas performance in the retention session relates to the effects on memory.Flumazenil and beta-CCt did not affect behavior. Midazolam (2.0 mg/kg) facilitated acquisition performance, while DMCM (1.0 and 2.0 mg/kg) induced the opposite effect. Flumazenil antagonized both effects. Beta-CCt potentiated the effect of midazolam, and partly antagonized the effect of DMCM. Midazolam (0.5 and 1.0 mg/kg) and zolpidem (1.0-3.0 mg/kg) impaired, while DMCM (0.1 mg/kg) facilitated the subjects' performance in the retention test. The amnesic effects were attenuated but not fully reversed, while the effect of DMCM was counteracted by both antagonists.The results indicate the alpha1-subunit interferes with the anxiolytic effect of a benzodiazepine site agonist and may contribute to the DMCM-induced anxiogenic effect. It is also substantially involved in the bidirectional memory processing in the active avoidance paradigm.

Recent research using genetically modified mice has pointed to the specific contribution of individual receptor subtypes to the various effects of benzodiazepines. The aim of this study was to examine the relative significance of alpha(1)-containing GABA(A) receptors in the effects of modulators at the benzodiazepine site in the elevated plus-maze (EPM) under dim red light in rats. We tested the effects of the non-selective antagonist flumazenil (0-20.0 mg/kg), the preferential alpha(1)-subunit selective antagonist beta-carboline-3-carboxylate-t-butyl ester (beta-CCt, 0-30.0 mg/kg), the non-selective agonist midazolam (0-2.0 mg/kg), the preferential alpha(1)-subunit selective agonist zolpidem (0-2.0 mg/kg) and the non-selective inverse agonist methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM, 0-2.0 mg/kg). The influence of flumazenil (10.0 mg/kg) and beta-CCt (30.0 mg/kg) on the effects of both kinds of agonists were also examined. The standard spatio-temporal parameters reflecting anxiety (percentage of open arm entries and time) and locomotion (closed and total arm entries) were analyzed. beta-CCt did not affect behavior, while flumazenil at the highest dose (20.0 mg/kg) decreased indices of open arm activity and total arm entries. Midazolam at the dose of 1.0 mg/kg significantly increased the percentage of open arm time, whereas at 2.0 mg/kg both anxiety-related parameters were increased. In contrast to the open arm entries, the open arm time was independent of the decreased closed arm entries, observed at 2.0 mg/kg. Flumazenil abolished these effects, whereas beta-CCt partially potentiated the anxiolytic actions of midazolam. Zolpidem significantly increased both open-arm indices at 1.0 mg/kg, but the effect was dependent on the decreased closed arm entries. The selectivity of the anxiolytic-like effects of zolpidem was further checked under brighter white illumination. In these settings, the influence on anxiety-related, but not activity-related parameters, was absent. All of the activity-related effects of midazolam and zolpidem were mainly counteracted by both antagonists. DMCM produced significant anxiogenic effects at 1.0 mg/kg (open arm time) and 2.0 mg/kg (both parameters). beta-CCt (30.0 mg/kg) and flumazenil at higher dose (20.0 mg/kg) antagonized the effects of DMCM. The results indicate the anxiolytic effects of a non-selective benzodiazepine site agonist involve a predominant role of subunits other than alpha(1), whereas the behavioral indices of the anxiolytic-like properties of an alpha(1)-selective ligand, if observed, depend on the experimental settings and the changes in locomotor activity, and hence were behaviorally non-specific. The present results generally correspond well to the behavioral findings with the genetically modified mice. On the other hand, the relative significance of the alpha(1)-subunit in the anxiogenic effects of DMCM could not be clearly deduced.

We present a relatively simple and robust algorithm for finding optimal and near optimal solutions for antenna design based on a combination of random and Nelder-Mead simplex algorithms. We considered the design of a Yagi-Uda antenna, as an example, for two reasons: it has many near optimal solutions; analysis of such an antenna is relatively quick. The presented combinations of random and Nelder-Mead methods are relatively simple and robust optimization algorithms. They can be advantageous in situations where the error function (the difference between the given criteria and the found solution) has many local minima of approximately the same depth or when formulation of the error function is complicated due to multiple involved criteria. Insight into near optimal solutions, which could be easily found using the proposed methods, offers more freedom in antenna design.

The purpose of the present study was to examine the influence of midazolam on the retrieval and acquisition rate of two-way active avoidance in rats. In the schedule 2 x 100 trials, the effects of midazolam (0.5-5.0 mg/kg), benzodiazepine binding site antagonist flumazenil (2.5-10.0 mg/kg), specific antagonist of GABA(A) receptor, bicuculline (0.5-4.0 mg/kg), and the blocker of GABA(A) receptor containing Cl(-) channels, picrotoxin (1.0-5.0 mg/kg), on the second day retrieval of avoidance performance were investigated, as well as the influence of the used blockers of GABA(A) receptor function on midazolam effects. Furthermore, the effect of midazolam (1.0 mg/kg) on acquisition rate in the 5 x 50 schedule, as well as the effects of third day treatment changing in that paradigm, was examined. Throughout the study, drugs were given intraperitoneally, 30 min before testing. Midazolam at the dose of 1.0 mg/kg facilitated avoidance retrieval, whereas flumazenil and bicuculline did not significantly change behavior. Picrotoxin (5.0 mg/kg) diminished performance. All three kinds of blockers used abolished facilitatory action of midazolam, confirming GABAergic mediation of the effect of benzodiazepine. Midazolam (1.0 mg/kg) increased acquisition rate during five consecutive days relative to saline, but without significant effect on the first day acquisition. In the case of third day changing of treatments, the intersection of regression rate lines was detected. Results from active avoidance paradigm experimentally support the findings from human studies that in certain circumstances, benzodiazepines, potentiating GABAergic neurotransmission, could produce retrieval-enhancing effects in memory tasks.

Antenna optimization usually leads to a black-box optimization problem with many local minima. The presented algorithm combines random search with information about the optimization space, obtained after each trial, to find local minima quickly. The probability of splitting parts of the space is proportional to the reciprocal of the error function and is updated after each iteration. The algorithm can be used as a standalone optimization procedure or as a starting stage in hybrid optimization.

U radu se kritički razmatraju postupci javne nabave prema važećem hrvatskom zakonodavstu te pretpostavke i postupci pravne zaštite sudionika.

This study investigated the impact of modulating the γ -aminobutyric acid A (GABA) A –benzodiazepine receptor complex activity on the rat frontal cortex slices oxygen consumption (QO 2 ), polarographically determined using the biological oxygen monitor. Throughout the study, diazepam, flumazenil and picrotoxin were administered i.p. 30 min before sacrificing animals and obtaining slice preparations, while GABA was added directly into the medium in the reaction chamber. GABA decreased QO 2 in concentrations of 5×10 −4 , 10 −2 and 5×10 −2 mol l −1 , while 10 −5 and 10 −6 mol l −1 GABA had no effect, as well as diazepam, flumazenil and picrotoxin. All diazepam doses (1, 2.5 and 5 mg kg −1 ) increased action of 5×10 −4 mol l −1 GABA, whereas 2.5 mg kg −1 dose amplified the effect of 10 −6 mol l −1 GABA. Flumazenil and picrotoxin (5 mg kg −1 both) blocked diazepam’s effects. Flumazenil augmented 10 −6 mol l −1 GABA effects, while picrotoxin and flumazenil abolished the effects of 5×10 −4 mol l −1 GABA. To our knowledge, this is the first study to examine the influence of modulation of GABA A –benzodiazepine receptor function on cerebral metabolism of oxygen in in vitro settings. The results are in accordance with those obtained in numerous in vivo studies, pointing to the moderate level of influence of GABA A –benzodiazepine receptor complex on QO 2 regulation.

The aim of the study was to investigate the morphology of mesothelial cells of the peritoneum of patients with terminal renal failure (TRF), taken by the biopsy immediately before the onset of peritonal dialysis (PD), and to compare it with the findings in patients with PD. The samples were prepared in the way standard for light microscopy and transmission electron microscopy. In patients with TRF intracytoplasmatic inclusions could be observed, unusual protrusions of mesothelial apical surfaces, deformation of mesothelial cells and their detachment from the basal membrane, as well as the dilatated cisternae of granulated endoplasmatic reticulum with filamentous structures in some of them. In patients on PD cytoplasmic protrusions of different shapes and contents were observed at the surface of mesothelial cells, multiplication of basal membrane, occurrence of young forms of mesothelial cells as well as the detachment of those cells from the basal lamina.

Introduction Neurosteroid dehydroepiandrosterone (DHEA) has been associated to various functions in the central nervous system, including modulation of memory and behavior. It has been suggested that the effects of DHEA are mediated through several neurotransmitter systems; however its mechanisms of action are not fully understood. This study aimed to investigate the behavioral profile of DHEA in the forced swim test (FST), and also its impact on locomotor activity. Methods FST was performed in a glass cylinder, 45 cm high, 20 cm diameter filled with water up to a height of 30 cm. On the first day, male Wistar rats were forced to swim for 15 min. Rats were re-exposed to the FST for a single 5 min session, after the acute and chronic challenge with saline or DHEA. The measurement of locomotor activity was performed in a clear Plexiglas box (40×25×35 cm) for 30 min without any habituation period. The data were analyzed by one-way ANOVA, followed by Dunnett's test. Results In FST, ANOVA indicated statistically significant effects of DHEA. Dunnett's analysis showed that DHEA significantly decreased the duration of immobility at the dose of 10 mg/kg, exerting acute, but also chronic antidepressant-like effects. However, DHEA did not induce significant differences in time of struggling behavior. ANOVA did not show a significant effect of treatment on locomotor activity. Conclusions These data experimentally support the findings that under certain circumstances, DHEA might have triggered the antidepressantlike effects in rats. Furthermore, these effects were not confounded by change in motor function.

U članku su prezentirana najnovija naučna dostignuća u oblasti radio-izviđanja signala sa frekvencijskim skakanjem. Verovatnoća otkrivanja signala sa frekvencijskim skakanjem pomoću najsavremenijih izviđačkih radio-prijemnika ili digitalnih radio-goniometara, proračunava se na opštim osnovama, pri čemu se posebna pažnja posvećuje višekanalnim izvidačkim radio-prijemnicima, pretraživanju sa preklapanjem i režimu frekvencijskog skakanja. U članku je detaljno opisano vremensko podešavanje koraka pretraživanja izviđačkog radio-prijemnika, sa korakom frekvencijskog skakanja izviđanog radio-signala. Da bi se problem pojednostavio, razmatrani su idealni uslovi., This article is intended to present the latest scientific findings about the interception of frequency hoping signals. The probability of intercepting frequency hopping signals by means of modern search receivers or scanning direction finders is calculated on a general basis and with particular attention to multichannel receivers and overlapping search and frequency hopping ranges. The article also deals in detail with the timing of the receiver sequence coinciding with the hopper sequence. For the sake of simplicity, ideal conditions are assumed.

The object of this theoretical investigation is to determine dynamic properties of such a layer which can provide a standard against which we may compare the results of non-destructive evaluation measurements. It is shown that phase velocity of such waves strongly depends on both direction of propagation and angle between two families of fibres.