1,199 research outputs found

    Angular and spatial distributions of protons channeled in a bent and radially deformed single-wall boron-nitride nanotubes

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    This study is devoted to the angular and spatial distribution of protons channeling through a bent and radially deformed single-wall boron-nitride nanotubes (SWBNNTs). These nanotubes are more thermal and chemical stable then carbon nanotubes, and they are good candidates for future channeling experiments. This investigation is continuation of our previous study [1, 2] and now we investigate channeling properties of SWBNNTs as a function of the very realistic effects: bending angle of nanotube and its radial deformation. For the first time we presented here investigation of these effects with boron-nitride nanotubes and combination of both effect. The angular and spatial distributions of channeled protons were generated using the Molière’s expression for the continuum potential of the SWBNNT’s atoms and computer simulation method. We also calculate the total yield of protons channeled in the nanotubes as a function of the bending angle. We demonstrate that varying bending angle and taking into account radial deformation we can get a significant rearrangement of the propagating protons within the boron-nitride nanotube. This investigation may be very useful to give us detailed information on the relevant interaction potentials inside SWBNNTs and for creating nanosized proton beams to be used in different applications in medicine and materials science. © 2019, Editura Academiei Romane. All rights reserved

    Angular and spatial distributions of protons channeled in a bent and radially deformed single-wall boron-nitride nanotubes

    Get PDF
    This study is devoted to the angular and spatial distribution of protons channeling through a bent and radially deformed single-wall boron-nitride nanotubes (SWBNNTs). These nanotubes are more thermal and chemical stable then carbon nanotubes, and they are good candidates for future channeling experiments. This investigation is continuation of our previous study [1, 2] and now we investigate channeling properties of SWBNNTs as a function of the very realistic effects: bending angle of nanotube and its radial deformation. For the first time we presented here investigation of these effects with boron-nitride nanotubes and combination of both effect. The angular and spatial distributions of channeled protons were generated using the Molière’s expression for the continuum potential of the SWBNNT’s atoms and computer simulation method. We also calculate the total yield of protons channeled in the nanotubes as a function of the bending angle. We demonstrate that varying bending angle and taking into account radial deformation we can get a significant rearrangement of the propagating protons within the boron-nitride nanotube. This investigation may be very useful to give us detailed information on the relevant interaction potentials inside SWBNNTs and for creating nanosized proton beams to be used in different applications in medicine and materials science. © 2019, Editura Academiei Romane. All rights reserved

    Bifid and secondary superior nasal turbinates

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    The lateral nasal wall contains the nasal turbinates (conchae) which are used as landmarks during functional endoscopic surgery. Various morphological pos- sibilities of turbinates were reported, such as bifidity of the inferior turbinate and extra middle turbinates, such as the secondary middle turbinate. During a retrospective cone beam computed tomography study of nasal turbinates in a patient we found previously unreported variants of the superior nasal turbina- tes. These had, bilaterally, ethmoidal and sphenoidal insertions. On the right side we found a bifid superior turbinate and on the left side we found a secondary superior turbinate located beneath the normal/principal one, in the superior nasal meatus. These demonstrate that if a variant morphology is possible for a certain turbinate, it could occur in any nasal turbinate but it has not been yet observed or reported.

    Inhibition of endothelial cell functions and of angiogenesis by the metastasis inhibitor NAMI-A

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    NAMI-A is a ruthenium-based compound with selective anti-metastasis activity in experimental models of solid tumours. We studied whether this activity was dependent on anti-angiogenic ability of NAMI-A. We thus investigated its in vitro effects on endothelial cell functions necessary for angiogenesis to develop, as well as its in vivo effects in the chick embryo chorioallantoic membrane model. Endothelial cell proliferation, chemotaxis, and secretion of the matrix-degrading enzyme metalloproteinase-2 were inhibited by NAMI-A in a dose-dependent manner, and without morphologic signs of cell apoptosis or necrosis. Lastly, NAMI-A displayed a dose-dependent in vivo anti-angiogenic activity in the chorioallantoic membrane model. These data suggest that the anti-angiogenic activity of NAMI-A can contribute to its anti-metastatic efficacy in mice bearing malignant solid tumours

    Helianthus annuus: A new important element of the non-arable and arable flora in Serbia’s region of southern Banat

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    Four species of the Helianthus genus have been found in the non-arable and arable communities in Vojvodina and Serbia, namely: H. annuus, H. tuberosus, H. decapetalus and H. scaberimus. Studies conducted hitherto have shown that Helianthus annuus has the highest frequency in all weed phytocoenoses examined so far. The spreading of H. decapetalus and H. scaberimus, introduced to Vojvodina from the neighboring Hungary and Romania, has still not assumed alarming proportions in quantitative terms, but a tendency has been observed of their further spreading. It is therefore necessary to monitor and study the trend of their expansion over the coming period.

    Organic Lamb Meat Production in Serbia Based on Autochthonous Zackel Breed: Opportunities and Challenges

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    The global growing tendency of lamb and mutton meat production has been emphasized. The fastest growing meat production industry on a global level is lamb and mutton meat production. Lamb meat production increase is primarily based on genetic improvement of sheep breeds, reproduction management and disease reduction. The new Strategy for Agriculture and Rural Development in Serbia from 2014 to 2024 defines goals and priorities for further development of agriculture. One of priority topics is the promotion of organic production. Organic lamb production is a great opportunity for rural regions development. Botanical composition analyses, as well as plants nutrition value, have shown that natural resources of regions in Serbia have great potentials for organic lamb production. Basic principles of organic production promote well adapted, autochthonous breeds. Various types of Zackel sheep are important genetic resources, evolutionary adapted on specific conditions and extreme climate. The study evaluated the value of various types of Zackel sheep populations in the regions where they are traditionally reared with special emphasis on some traits such as health status and robustness, important for organic production. Disease frequency analysis in different Zackel type populations has shown that gastrointestinal parasitic infections represent the main health problem in sheep farming. The introduction of veterinary medicine standards in organic sheep production is a great challenge. Considering that conventional prevention and medication are forbidden in organic production, veterinary control of parasitic infections is not satisfying. Our investigations are focused on preventive measure and genetic resistance/tolerance to parasitic infections of various types of Zackel sheep as very important for organic lamb production

    Management of facial paralysis following treatment of neurosurgical tumours

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    The purpose of this study is to present our experience on improving the quality of life of patients with facial paralysis due to an operated intracranial tumour, by performing minimally invasive static reanimation procedures. We reviewed the clinical information pertaining to neurosurgical patients with facial paralysis that underwent static reanimation. The study included 11 patients with complete facial nerve paralysis of all nerve branches, that reported different primary complaints upon presentation. The performed procedures consisted of gold plate insertion into the superior eyelid, inferior eyelid ectropion correction or suture suspension. The functional results were favourable in all cases and the resulting appearance was acceptable. The choice of the different techniques used is discussed. Good outcomes are possible using static reanimation with an adequate adaptation of the techniques to the main patient complaint

    Parazitski korovi - osnovne karakteristike, taksonomija, biodiverzitet i rasprostranjenje, I - vilina kosica (Cuscuta L.)

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    The first part of this study provides the basic characteristics of dedder (Cuscuta L.). The most important data concerning the taxonomy, diversity and distribution of Cuscuta are presented. There are eighteen Cuscuta species in Europe, while ten species have been found in the Balkans, including Serbia. Various Cuscuta species are hereby described in detail from the standpoints of taxonomy, biodiversity and chorology. The survey also contains all the relevant data concerning the plants on which certain Cuscuta species live as parasites.Prvi deo ove studije obuhvata prikaz osnovnih karakteristika viline kosice (Cuscuta L.). Dati su najvažniji podaci o taksonomiji, biodiverzitetu i rasprostranjenju vrsta roda Cuscuta. Utvrđeno je da u Evropi egzistira 18 vrsta roda Cuscuta, a 10 na Balkanskom poluostrvu i Srbiji. Detaljno su opisane vrste viline kosice sa taksonomskog, biodiverzitctskog i horološkog stanovišta. Izneti su podaci i o biljkama na kojima parazitiraju pojedine vrste viline kosice

    Biološka i ekološka proučavanja korova na području Srbije - razvoj, današnje stanje, perspektive

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    Weed diversity is highly pronounced in the territory of Serbia. Of a total of 3, 272 registered vascular plant species in Serbia, weeds account for 1,008. Such a wide range of weeds has resulted in a significant diversity of phytocoenological, ecological, anatomical-morphological, physiological and other characteristics of weed plants. The article gives a synthesized review of research into weed plant communities. Further on, some crucial results in ecological and ecophysiological research are presented, such as relating to water and photosynthetic regime, respiration intensity, compensation point, organic production, weed-to-weed and weed-to-cultivated plant relations (competition, allelopathy) and weed resistance to herbicides. Finally, based on a survey of hitherto research and the current status of weed science research, we pointed at possible directions for future biological and ecological weed research in Serbia.U radu je prvo dat sintetski pregled istraživanja korovskih biljnih zajednica. Zatim su pregledno prikazani najhitniji rezultati ekoloških odnosno kofizioloških proučavanja, koja se odnose na vodni i fotosintetski režim, intenzitet disanja, kompezacionu tačku, organsku produkciju, međusobne odnose između korova kao i korova i gajenih biljaka (kompeticija, alelopatija) i rezistentnost korova prema herbicidima. Na kraju je na osnovu rezimea dosadašnjih istraživanja i stanja u herbologiji danas, ukazano na pravce budućih bioloških i ekoloških proučavanja korova
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