Investigation of effects of two environmental heavy metals in a combined exposure model on the nervous system in rats

In the present study, the interaction of inhalational and oral exposure to manganese and lead was investigated. Young adult male Wistar rats (2 x 10 per group) were treated orally with MnCl2 (15 and 60 mg/kg b.w.) or Pb acetate (80 and 320 mg/kg) for 3 or 6 weeks. Then, one half of the groups was further treated by intratracheal instillation of nanoparticulate MnO2 (2.63 mg/kg) or PbO (2 mg/kg) for an equal period of time. Body weight gain and signs of general toxicity were regularly checked. Finally, the rats’ motor behavior was tested in an open field box, and their spontaneous and evoked cortical electrical activity was recorded in urethane anesthesia. MnO2 nanoparticles caused disproportionately strong reduction of body weight gain but with Pb the weight effect was more dependent on dose. In the open field test, Mn caused hypomotility, more strongly after 6 weeks oral plus 6 weeks intratracheal than after 6 weeks oral treatment. Pb-treated rats showed increased ambulation but less rearing and somewhat longer local activity. Spontaneous cortical activity was shifted to higher frequencies after oral Mn application, but this change was not intensified by subsequent nanoparticle application. Oral Pb had an opposite effect. Cortical evoked potentials showed latency lengthening. In several cases, the effect of Mn and Pb was about as strong after 3 weeks oral plus 3 weeks intratracheal as after 6 weeks oral administration, although the summed dose was ca. two times lower in the former case. There can be a more-than-additive interaction between the amounts of heavy metals entering the organism in different routes and chemical forms

Petri Nets with Discrete Phase Type Timing: A Bridge Between Stochastic and Functional Analysis

Abstract The addition of timing specification in Petri Nets (PN) has followed two main lines: intervals for functional analysis or stochastic durations for performance and dependability analysis. The present paper proposes a novel technique to analyze time or stochastic PN models based on discretization. This technique can be seen as a bridge between the world of functional analysis and the world of stochastic analysis. The proposed discretization technique is based on the definition of a new construct called Discrete Phase Type Timing - DPT that can represent a discrete cumulative density function (cdf) over a finite support (or a deterministic cdf) as well as an interval with non-deterministic choice (or a deterministic duration). In both views, a preemption policy can be assigned and a strong (the transition must fire when the interval expires) or a weak (the transition can fire when the interval expires) firing semantics. The paper introduces the DPT construct and shows how the expanded state space can be built up resorting to a compositional approach based on Kronecker algebra. With this technique a functional model can be quantified by adding probability measures over the firing intervals without modifying the (compositional) structure of the PN model

Subacute exposure of rats by metal oxide nanoparticles through the airways: general toxicity and neuro-functional effects

In order to create an animal model of human inhalational exposure by industrial trAct metal fumes, nanoparticulate metal oxides (MnO2 , CdO2 , PbO) were synthesized and instilled into the trachea of rats 5 times a week for 6 weeks (metal doses per kg b.w.: 2.63 and 5.26 mg Mn; 0.04 and 0.4 mg Cd; 2 and 4 mg Pb). At the end, the rats’ body weight gain during the treatment was determined, the animals had an open field session to investigate their spontaneous motility, and finally spontaneous and stimulus-evoked cortical activity was recorded in urethane anaesthesia. Mn caused decrease of open field ambulation and rearing, Cd had no effect, whereas Pb caused decreased rearing and increased ambulation. Spontaneous cortical activity was shifted to higher frequencies with each metal. Cortical evoked potentials had lengthened latency, mainly with Mn and Cd; and increased frequency dependence with Cd and Pb but hardly with Mn. The effects proved indirectly that the metal content of the nanoparticles had access form the airways to the CNS. Our method seems suitable for modelling human nervous system damage due to inhaled nanoparticles

Tájesztétikai vizsgálatok a Medves-térség területén = Investigation of landscape aesthetics on the Medves region

A témában munkatársaimmal végzett eddigi kutatásaink során a tájesztétika elméleti és gyakorlati kérdéseit vizsgáltuk. Medves-térségi kutatási területünkön tájesztétikai vizsgálatokra alkalmas dokumentumokat (képeslapok, fotók, grafikák és festmények) rendszereztünk, majd kérdőívek segítségével adatokat gyűjtöttünk a területen élők és a turisták képeslapküldő szokásairól, elemeztük a megjelent képeslapok - a turizmusmarketing fontos eszközeinek - motívumrendszerét. A turisztikai szempontból rendkívül attraktív tájon ún. "festői utat" terveztünk, a terület két vára között beláthatósági térképet szerkesztettünk. Összegeztük a tájesztétika elméleti alapjait, kiemelve a tájkép, mint művészeti alkotás jelentőségét az évezredek során, illetve az embernek a folyton változó tájhoz fűződő kapcsolatát. Vizsgáltuk hogy jellegzetes tájképek milyen hatást gyakorolnak különböző korú (általános iskolai alsó- és felsőtagozatos, középiskolás, egyetemista) tanulókra és hallgatókra. Összegeztük a Medves-vidék idegenforgalmi szempontból jelentős, illetve a későbbiekben azzá tehető tájképi értékeket (vö. http://geography.hu/karancsi - Kutatások/Tájesztétika/Publikációk) | In this topic, together with my colleagues, we have mainly investigated theoretical and practical questions of landscape aesthetics. In our selected research area, the Medves-area we have built up an increased database (postcards, photos, paintigs and drawings) of documents applicable in landscape aesthetic research. Afterwards, using questionaires, we have collected information on the postcard-sending practice of tourists and locals, and analysed - applying the tools of tourism marketing - the motive-system of published postcards. We have produced a so-called 'painter's route' over the especially attractive landscapes of two castles in the research area. We have concluded and provided a theoretical basis to our research, emphasizing the importance of the landscape as an object of art in connection with the relation of humans to the ever-changing landscape. Moreover, we analysed the impact of landscape on students of different age (elementary and primary school, secondary school and university levels). A consecutive summary of landscape values with real or probable touristic importance has also been carried out (see http://geography.hu/karancsi - Kutatások/Tájesztétika/Publikációk)

Összetett reakciórendszerek egyensúlyi és kinetikai vizsgálata = Equilibrium and kinetic studies of complex chemical systems

A válaszreakciók korábban kidolgozott elméletére alapozva definiáltuk az egyensúlyi csatolás fogalmát. Bemutattuk, hogy - megfelelő körülmények között - szinte törvényszerűen jelentkeznek a Le Chatelier Braun elvnek látszólag ellentmondó jelenségek. Az egyensúlyi csatolás elméletileg megalapozott fogalom, s helyettesitheti a folyamatok egyszerüsitett értelmezéséböl származó, ellentmondásos termodinamikai csatolás fogalmát. Nyolc különböző összetett kinetikai rendszeren végeztünk kinetikai vizsgálatokat, s javasoltunk mechanizmust, amellyekkel számos egzotikus kinetikai jelenség (szuperkatalizis, mintázatképződés, tized-rendű reakció) értelmezhetővé vált. | Based on the theory of response reactions elaborated by us before, we have introduced the concept od equilibrium coupling. It was shown that - under appropriate conditions - the phenomena seemingly in contradiction with the L Catelier Barun principle are almost inevitable in multilple equilibrium systems. The equilibrium coupling is theorethically sound principle and may replace the concept of thermodynamic coupling which is originated from the simplified interpretation of the chemical reactions. Detailed kinetic studies have been carried out in eigth different complex kinetic systems. Based on the experiments appropriate mechanisms are suggested which interpret the different exotic phenomena (super-catalysis, pattern formation, formal reaction order of ten)

Ultra-low thermal conductivity in organic-inorganic hybrid perovskite CH3NH3PbI3

We report on the temperature dependence of thermal conductivity of single crystalline and polycrystalline organometallic perovskite CH3NH3PbI3. The comparable absolute values and temperature dependence of the two sample's morphologies indicate the minor role of the grain boundaries on the heat transport. Theoretical modelling demonstrates the importance of the resonant scattering in both specimens. The interaction between phonon waves and rotational degrees of freedom of CH3NH3+ sub-lattice emerges as the dominant mechanism for attenuation of heat transport and for ultralow thermal conductivity of 0.5 W/(Km) at room temperature