136 research outputs found

    POLIMER NANOKOMPOZITOK

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    A 2.1. fejezet műanyag nanokompozitokkal foglalkozik, különös tekintettel a járműiparban alkalmazható anyagok fejlesztésében elért eredményekre és az alkalmazási lehetőségekre

    LĂŠzerszinterelt prĂłbatestek kopĂĄs vizsgĂĄlata

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    A fémporok lézeres szinterezésével már funkcionális darabok is készíthetők. Az ismert alap mechanikai tulajdonságaik alapján nagy igénybevételű alkatrészekként gyártásánál is alkalmazhatóak. Mechanikusan működtetett alkatrészekként való használatukhoz a koptató igénybevétellel szembeni ellenállásuk megismerése szükséges. Cikkünkben MaragingSteel MS1 acélporból szinterezett próbatesteken és referencia anyagokon végeztünk koptató vizsgálatokat

    Study of 2D and 3D Methods for Worn Surface Analysis of Tool Materials

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    This paper is dealing with the comparison of the results given by different worn surface analysing methods. Maraging steel tool materials were used for the experiments. Specimens were produced by direct metal laser sintering from metal powder and by conventional way from rod having equivalent chemical content. The samples were age-hardened and surface treated by nitrocarburising and oxynitriding and they were tested by pin-on-disc type tribometer. The tribological behaviour was compared by using different methods for worn surface analysis. Worn area of the surface was determined by the surface profiles of 2D measurements and the worn surface volume was calculated by using 3D images of focus variation microscopy measurements

    Műanyag fröccsöntő szerszámbetétek szinterezési technológiája

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    Az 1.3 fejezet a szelektív lézer szinterezés, ezen belül is a DMLS (Direct Metal Laser Sintering) technológiával foglalkozik, bemutatja az eljárás jellemzőit, előnyeit és korlátait formakövető hűtőcsatornával rendelkező fröccsöntő szerszámbetétek gyártásában

    Enhanced Pollution Removal with Heat Reclamation in a Small Hungarian Wastewater Treatment Plant

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    The aim of the research is to outline the possibilities of utilizing waste heat in small municipal wastewater treatment plants. The facility, which was chosen as case-study, accepts about 2,300 m3 of raw sewage daily. In wintertime the wastewater temperature decreases to 10-14 °C which results in lower nitrification capacity based on measurement and validated model results. The excess heat of the wastewater would serve to increase the temperature of the aeration tank in order to enhance the microbiological activity and thus the efficiency of pollutant removal. The amount of reusable waste heat is calculated and with the help of dynamic simulation the effluent quality was determined to compare it with the original results. Increasing the temperature by 6 °C in the aerated tank, ammonium removal could be improved by 61%. This way not only the heat, but the nutrient pollution could be mitigated, too

    Membrane-Lipid Therapy in Operation: The HSP Co-Inducer BGP-15 Activates Stress Signal Transduction Pathways by Remodeling Plasma Membrane Rafts

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    Aging and pathophysiological conditions are linked to membrane changes which modulate membrane-controlled molecular switches, causing dysregulated heat shock protein (HSP) expression. HSP co-inducer hydroxylamines such as BGP-15 provide advanced therapeutic candidates for many diseases since they preferentially affect stressed cells and are unlikely have major side effects. In the present study in vitro molecular dynamic simulation, experiments with lipid monolayers and in vivo ultrasensitive fluorescence microscopy showed that BGP-15 alters the organization of cholesterol-rich membrane domains. Imaging of nanoscopic long-lived platforms using the raft marker glycosylphosphatidylinositol-anchored monomeric green fluorescent protein diffusing in the live Chinese hamster ovary (CHO) cell plasma membrane demonstrated that BGP-15 prevents the transient structural disintegration of rafts induced by fever-type heat stress. Moreover, BGP-15 was able to remodel cholesterol-enriched lipid platforms reminiscent of those observed earlier following non-lethal heat priming or membrane stress, and were shown to be obligate for the generation and transmission of stress signals. BGP-15 activation of HSP expression in B16-F10 mouse melanoma cells involves the Rac1 signaling cascade in accordance with the previous observation that cholesterol affects the targeting of Rac1 to membranes. Finally, in a human embryonic kidney cell line we demonstrate that BGP-15 is able to inhibit the rapid heat shock factor 1 (HSF1) acetylation monitored during the early phase of heat stress, thereby promoting a prolonged duration of HSF1 binding to heat shock elements. Taken together, our results indicate that BGP-15 has the potential to become a new class of pharmaceuticals for use in ‘membrane-lipid therapy’ to combat many various protein-misfolding diseases associated with aging

    Maternal Antibody Transmission in Relation to Mother Fluctuating Asymmetry in a Long-Lived Colonial Seabird: The Yellow-Legged Gull Larus michahellis

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    Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing passive immunity against infectious diseases to which hatchlings may be exposed, thereby affecting their fitness. It is nonetheless unclear whether the amount of maternal antibodies transmitted into egg yolks varies with female quality and egg laying order. In this paper, we investigated the transfer of maternal antibodies against type A influenza viruses (anti-AIV antibodies) by a long-lived colonial seabird, the yellow-legged gull (Larus michahellis), in relation to fluctuating asymmetry in females, i.e. the random deviation from perfect symmetry in bilaterally symmetric morphological and anatomical traits. In particular, we tested whether females with greater asymmetry transmitted fewer antibodies to their eggs, and whether within-clutch variation in yolk antibodies varied according to the maternal level of fluctuating asymmetry. We found that asymmetric females were in worse physical condition, produced fewer antibodies, and transmitted lower amounts of antibodies to their eggs. We also found that, within a given clutch, yolk antibody level decreased with egg laying order, but this laying order effect was more pronounced in clutches laid by the more asymmetric females. Overall, our results support the hypothesis that maternal quality interacts with egg laying order in determining the amount of maternal antibodies transmitted to the yolks. They also highlight the usefulness of fluctuating asymmetry as a sensitive indicator of female quality and immunocompetence in birds

    Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca)

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    Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female’s diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xanthophylls in the egg yolks decreased from Central Europe northwards. The most southern population (which is also the one found at the highest altitude) also showed relatively low carotenoid levels. Concentrations of β-carotene and zeaxanthin did not show any obvious geographical gradients. Egg yolks also contained proportionally more lutein and other xanthophylls in deciduous than in mixed or coniferous habitats. We suggest that latitudinal gradients in lutein and xanthophylls reflect the lower availability of lutein-rich food items in the northern F. hypoleuca populations and in montane southern populations, which start egg-laying earlier relative to tree phenology than the Central European populations. Similarly, among-habitat variation is likely to reflect the better availability of lutein-rich food in deciduous forests. Our study is the first to indicate that the concentration and profile of yolk carotenoids may show large-scale spatial variation among populations in different parts of the species’ geographical range. Further studies are needed to test the fitness effects of this geographical variation
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