35 research outputs found

    Biologically active adamantane derivatives

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    Derivati adamantana prekrivaju vrlo široko područje biološke aktivnosti. U ovom prikazu obrađeni su karakteristični primjeri: virustatici i antiparkinsonici, antibiotici, citostatici, hipoglikernici, antiaritmici i antihipertonici, sedativi i antidepresanti, imunosupresivni agensi i spazmolitici. Veća biološka aktivnost derivata adamantana u odnosu na poznate lijekove posljedica je veće otpornosti prema metabolitičkoj razgradnji, veće lipofilnosti i bržeg transporta kroz membrane stanica.Adamantane derivatives cover a very broad spectrum of biological activities. In this review characteristic examples are described: virustatics and antiparkinsonics, antibiotics, cytostatics, hypoglycemics, sedatives and antidepressants, antiarrythmics and antihypertonics, immunosuppressive agents and spasmolytics. A higher biological activity of adamantane derivatives than that of some known drugs is a consequence of their higher lipophilicity more rapid transport through cell membranes and higher resistance to metabolitic degradation

    HYGIENE, WELFARE AND BEHAVIOUR OF LAYING HENS HOUSED IN CONVENTIONAL CAGES AND ALTERNATIVE SYSTEMS

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    U radu je prikazano istraživanje dva sustava smještaja nesilica za proizvodnju konzumnih jaja, klasični i alternativni (aviarij) s posebnim osvrtom na higijenu zraka, dobrobit i ponašanje neslica. Higijenska kakvoća zraka u alternativnim sustavima držanja značajno je lošija u odnosu na konvencionalne sustave glede sadržaja bakterija, gljivica, prašine i endotoksina. Što se tiče dobrobiti i zadovoljenja bihevioralnih potreba alternativni sustavi odnosno aviariji su prihvatljiviji, međutim ovi sustavi s higijenskog stajališta ne zadovoljavaju s obzirom na veći broj zaprljanih i polomljenih jaja, kao i povećanu mogućnost izbijanja bolesti.This paper demonstrate two housing systems for production consume eggs, clasical and alternative (aviary) with special overview on air hygiene, welfare and laying hens behaviour. Hygienic air quality in alternative housing systems is significantly worse in relations with conventional systems regarding content of bacteria, fungi, dust and endotoxins. Considering welfare and satisfaction of behavioral needs alternative systems are acceptable, however this systems from hygienic point of view do not satisfy considering more dirty and broken eggs as well as great possibility of diseases emerge

    Gljivice kao sastavni dio bioaerosola u nastambama za muzne krave i nesilice konzumnih jaja

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    The air of animal dwellings can contain great amounts of bioaerosol composed of dust, bacteria, fungi, and endotoxins. The composition may depend on animal species, building construction, animal accommodation, and microclimate parameters, to name just a few factors. Pathogens contained may be a serious threat to animal and human health. The aim of our study was to analyse the fungi aerosol content in a stable housing dairy cows and in a coop for laying hens over the three autumn months of 2007. The air was sampled on Petri dishes with Sabouraud glucose agar. After laboratory treatment, we identifi ed the most common fungi. Their count in the stable ranged from 3.98x103 CFU m-3 to 5.11x104 CFU m-3 and in the coop from 6.89 x104 CFU m-3 to 1.13x105 CFU m-3. The difference between the two animal dwellings was statistically different at the level of p<0.05. In both dwellings, the most common were the fungi Aspergillus sp., Penicillium sp., and yeasts, followed by Cladosporium sp., Fusarium sp., Mucor sp., Scopulariopsis sp., Alternaria sp., and Rhizopus sp. Our results are entirely in line with values reported in literature and are at the lower end of the range. They call for further investigation that would eventually lead to setting air quality standards for animal dwellings and to developing reliable monitoring systems in order to ensure safe food and safe environment.U zraku nastambi za držanje životinja stvaraju se znatne količine bioaerosola. Njega čine prašina, bakterije, gljivice, endotoksini i plinovi. Brojnost im ovisi o građevinsko-tehničkim značajkama nastambi, naseljenosti životinjama, načinu držanja, temperaturno-vlažnim odnosima u staji i aktivnostima oko hranjenja, mužnje, skupljanja jaja i drugih poslova. Ove čestice, ako su patogene, mogu biti ozbiljna prijetnja za zdravlje ljudi. Mjerenja su obavljana u staji muznih krava te u objektu za nesilice, 2007. godine, tijekom tri jesenja mjeseca. Zrak je uzorkovan na Petrijeve zdjelice sa Sabouraudovim glukoznim agarom, uređajem MAS 100. Nakon obrade u laboratoriju, prema osnovnim i mikromorfološkim osobinama poraslih kolonija identifi cirani su najčešće zastupljeni rodovi gljivica. Srednja vrijednost broja gljivica u zraku staje za muzne krave kretala se od 3,98x103 CFU m-3 do 5,11x104 CFU m-3. Broj gljivica u zraku objekta za nesilice kretao se od 6,89x104 CFU m-3 do 1,13x105 CFU m-3. Ove vrijednosti statistički su se značajno razlikovale na razini p<0,05. U obje pretraživane nastambe najčešće su bili zastupljeni rodovi Aspergillus, Penicillium i kvasnice. U manjem postotku utvrđene su gljivice iz rodova Cladosporium sp., Fusarium sp., Mucor sp., Scopulariopsis sp., Alternaria sp. i Rhizopus sp. Rezultati ovih istraživanja o kvantitativnom i kvalitativnom sastavu gljivica u zraku pretraženih nastambi potpuno su u skladu s vrijednostima zabilježenim u literaturi te se nalaze na donjim granicama opisanih raspona. Utvrđeni broj i rodovi gljivica ukazuju na nužnost daljnjih istraživanja te potrebu postavljanja standardnih vrijednosti glede kvalitete zraka u nastambama za životinje, kao i razvoj vjerodostojnog sustava praćenja navedenih čimbenika, s ciljem stvaranja sigurne hrane i sigurnog okoliša

    The radial distribution of dust species in young brown dwarf disks

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    We present a study of the radial distribution of dust species in young brown dwarf disks. Our work is based on a compositional analysis of the 10 and 20 micron silicate emission features for brown dwarfs in the Taurus-Auriga star-forming region. A fundamental finding of our work is that brown dwarfs exhibit stronger signs of dust processing in the cold component of the disk, compared to the higher mass T Tauri stars in Taurus. For nearly all of our targets, we find a flat disk structure, which is consistent with the stronger signs of dust processing observed in these disks. For the case of one brown dwarf, 2M04230607, we find the forsterite mass fraction to be a factor of ~3 higher in the outer disk compared to the inner disk region. Simple large-scale radial mixing cannot account for this gradient in the dust chemical composition, and some local crystalline formation mechanism may be effective in this disk. The relatively high abundance of crystalline silicates in the outer cold regions of brown dwarf disks provides an interesting analogy to comets. In this context, we have discussed the applicability of the various mechanisms that have been proposed for comets on the formation and the outward transport of high-temperature material. We also present Chandra X-ray observations for two Taurus brown dwarfs, 2M04414825 and CFHT-BD-Tau 9. We find 2M04414825, which has a ~12% crystalline mass fraction, to be more than an order of magnitude brighter in X-ray than CFHT-BD-Tau 9, which has a ~35% crystalline mass fraction. Combining with previous X-ray data, we find the inner disk crystalline mass fractions to be anti-correlated with the X-ray strength.Comment: Accepted in MNRA

    The complex circumstellar environment of HD142527

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    The recent findings of gas giant planets around young A-type stars suggest that disks surrounding Herbig Ae/Be stars will develop planetary systems. An interesting case is HD142527, for which previous observations revealed a complex circumstellar environment and an unusually high ratio of infrared to stellar luminosity. Its properties differ considerably from other Herbig Ae/Be stars. This suggests that the disk surrounding HD142527 is in an uncommon evolutionary stage. We aim for a better understanding of the geometry and evolutionary status of the circumstellar material around the Herbig Ae/Be star HD142527. We map the composition and spatial distribution of the dust around HD142527. We analyze SEST and ATCA millimeter data, VISIR N and Q-band imaging and spectroscopy. We gather additional relevant data from the literature. We use the radiative transfer code MCMax to construct a model of the geometry and density structure of the circumstellar matter, which fits all of the observables satisfactorily. We find that the disk of HD142527 has three geometrically distinct components separated by a disk gap running from 30 to 130 AU. There is a geometrically flat inner disk running from 0.3 AU up to 30 AU; an optically thin halo-like component of dust in the inner disk regions; and a massive self-shadowed outer disk running from 130 AU up to 200 AU. We derived a total dust mass in small grains of 10^-3 M0 and a vertical height of the inner wall of the outer disk of h = 60 AU. ....Comment: 13 pages, 17 figures. Accepted by A&A 14 January 201

    Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers

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    We present a review of the interplay between the evolution of circumstellar disks and the formation of planets, both from the perspective of theoretical models and dedicated observations. Based on this, we identify and discuss fundamental questions concerning the formation and evolution of circumstellar disks and planets which can be addressed in the near future with optical and infrared long-baseline interferometers. Furthermore, the importance of complementary observations with long-baseline (sub)millimeter interferometers and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics Review"; The final publication is available at http://www.springerlink.co

    Low abundance, strong features: Window-dressing crystalline forsterite in the disk wall of HD 100546

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    Forsterite is one of the crystalline dust species that is often observed in protoplanetary disks and solar system comets. Being absent in the interstellar medium, it must be produced during the disk lifetime. It can therefore serve as a tracer of dust processing and disk evolution, which can lead to a better understanding of the physical processes occurring in the disk, and possibly planet formation. However, the connection of these processes with the overall disk crystallinity remains unclear. We aim to characterize the forsterite abundance and spatial distribution in the disk of the Herbig Be star HD 100546, to investigate if a connection exists with the large disk gap. We use a 2D radiative transfer code, MCMax, to model the circumstellar dust around HD 100546. We use VISIR Q-band imaging to probe the outer disk geometry and mid-infrared features to model the spatial distribution of forsterite. The temperature-dependent shape of the 69 micron feature observed with Herschel PACS is used as a critical tool to constrain this distribution. We find a crystalline mass fraction of 40 - 60 %, located close to the disk wall between 13 and 20 AU, and possibly farther out at the disk surface. The forsterite is in thermal contact with the other dust species. We put an upper limit on the iron content of forsterite of 0.3 %. Optical depth effects play a key role in explaining the observed forsterite features, hiding warm forsterite from view at short wavelengths. The disk wall acts as a showcase: it displays a localized high abundance of forsterite, which gives rise to a high observed crystallinity, while the overall mass fraction of forsterite is a factor of ten lower.Comment: A&A accepted, 17 pages, 14 figure

    Morphological Evolution of Spiders Predicted by Pendulum Mechanics

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    [Background] Animals have been hypothesized to benefit from pendulum mechanics during suspensory locomotion, in which the potential energy of gravity is converted into kinetic energy according to the energy-conservation principle. However, no convincing evidence has been found so far. Demonstrating that morphological evolution follows pendulum mechanics is important from a biomechanical point of view because during suspensory locomotion some morphological traits could be decoupled from gravity, thus allowing independent adaptive morphological evolution of these two traits when compared to animals that move standing on their legs; i.e., as inverted pendulums. If the evolution of body shape matches simple pendulum mechanics, animals that move suspending their bodies should evolve relatively longer legs which must confer high moving capabilities.[Methodology/Principal Findings] We tested this hypothesis in spiders, a group of diverse terrestrial generalist predators in which suspensory locomotion has been lost and gained a few times independently during their evolutionary history. In spiders that hang upside-down from their webs, their legs have evolved disproportionately longer relative to their body sizes when compared to spiders that move standing on their legs. In addition, we show how disproportionately longer legs allow spiders to run faster during suspensory locomotion and how these same spiders run at a slower speed on the ground (i.e., as inverted pendulums). Finally, when suspensory spiders are induced to run on the ground, there is a clear trend in which larger suspensory spiders tend to run much more slowly than similar-size spiders that normally move as inverted pendulums (i.e., wandering spiders).[Conclusions/Significance] Several lines of evidence support the hypothesis that spiders have evolved according to the predictions of pendulum mechanics. These findings have potentially important ecological and evolutionary implications since they could partially explain the occurrence of foraging plasticity and dispersal constraints as well as the evolution of sexual size dimorphism and sociality.This paper has been written under a Ramón y Cajal research contract from the Spanish Ministry of Science and Culture (MEC) to JML and a FPI scholarship (BES-2005-9234) to GC. This work has been funded by MEC grants CGL2004-03153 and CGL2007-60520 to JML and GC, as well as CGL2005-01771 to EMPeer reviewe

    On the origin and evolution of the material in 67P/Churyumov-Gerasimenko

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    International audiencePrimitive objects like comets hold important information on the material that formed our solar system. Several comets have been visited by spacecraft and many more have been observed through Earth- and space-based telescopes. Still our understanding remains limited. Molecular abundances in comets have been shown to be similar to interstellar ices and thus indicate that common processes and conditions were involved in their formation. The samples returned by the Stardust mission to comet Wild 2 showed that the bulk refractory material was processed by high temperatures in the vicinity of the early sun. The recent Rosetta mission acquired a wealth of new data on the composition of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) and complemented earlier observations of other comets. The isotopic, elemental, and molecular abundances of the volatile, semi-volatile, and refractory phases brought many new insights into the origin and processing of the incorporated material. The emerging picture after Rosetta is that at least part of the volatile material was formed before the solar system and that cometary nuclei agglomerated over a wide range of heliocentric distances, different from where they are found today. Deviations from bulk solar system abundances indicate that the material was not fully homogenized at the location of comet formation, despite the radial mixing implied by the Stardust results. Post-formation evolution of the material might play an important role, which further complicates the picture. This paper discusses these major findings of the Rosetta mission with respect to the origin of the material and puts them in the context of what we know from other comets and solar system objects

    Speciation of nano and ionic form of silver with capillary electrophoresis-inductively coupled plasma mass spectrometry.

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    Research in the area of new nanomaterials has been given high priority as having an enormous economic potential. Due to marked antimicrobial effect, silver nanoparticles (AgNPs) are one of the most commercialized and successfully exploited nanomaterials in a wide range of medical and consumer products.In biological and environmental compartments, AgNPs undergo different transformations including interaction with organic molecules, such as proteins, and dissolution. Hyphenated systems consisting of capillary electrophoresis (CE) coupled to sensitive element detection like ICP-MS can be considered as the promising methods for speciation analysis of AgNPs. Here, we investigated applicability of different CE methods hyphenated to ICP-MS for speciation of AgNPs in biological systems.The paper presents approach to analyze species formed in interaction of AgNPs with metallothionein (MT) as model protein. As AgNPs might be coated by MTs in bio-fiuids, we installed first a CE-speciation method for MT-1 and MT-2. Although this separation was successful, no reproducible and well separated peaks for AgNPs or Ag* were achieved. Therefore, we focused on developing methods for separating MT-1, MT-2, Ag* and AgNPs. Several buffer conditions were tested to improve their separation and to minimize Ag-sticking to capillary walls. All compounds of interest in this paper, i.e. MT-1, MT-2, Ag+ and AgNPs, were well separated from each other using tetramethyl-ammoniumhydroxide as electrolyte. In mixed samples, we observed Ag+ being completely associated with MT-1, while Ag*-association with MT-2 was less: The highest quantity of Ag* was associated with a compound having low Cd-concentration, while another relevant fraction was bound to MT-2. Free Ag* was also seen in minor amounts whereas another Ag-peak at 8.13 min remains unknown. Most AgNPs remained free. AgNPs were only little associated with MT-1, the latter being split into two peak signals, whereas association with MT-2 was high. Only 15% of AgNPs remained unbound.We demonstrated CE hyphenated to the ICP-MS as promising and elegant technique to study AgNPs in biological systems. (C) 2018 Elsevier B.V. All rights reserved
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