444 research outputs found

    Evidence for electron-phonon interaction in Fe1āˆ’x_{1-x}Mx_{x}Sb2_{2} (M=Co, Cr) single crystals

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    We have measured polarized Raman scattering spectra of the Fe1āˆ’x_{1-x}Cox_{x}Sb2_{2} and Fe1āˆ’x_{1-x}Crx_{x}Sb2_{2} (0ā‰¤xā‰¤\leq x\leq 0.5) single crystals in the temperature range between 15 K and 300 K. The highest energy B1gB_{1g} symmetry mode shows significant line asymmetry due to phonon mode coupling width electronic background. The coupling constant achieves the highest value at about 40 K and after that it remains temperature independent. Origin of additional mode broadening is pure anharmonic. Below 40 K the coupling is drastically reduced, in agreement with transport properties measurements. Alloying of FeSb2_2 with Co and Cr produces the B1g_{1g} mode narrowing, i.e. weakening of the electron-phonon interaction. In the case of Ag_{g} symmetry modes we have found a significant mode mixing

    Application of a widely-used tropical anti-worm agent, mebendazole, in modern oncology

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    Although clinical trials have not been completed, it has already been confirmed that mebendazole, a well-known anti-parasitic drug widely used in the tropical areas, inhibits cancer cell growth. Preclinical studies show that mebendazole notably impedes the growth of malignant and metastatic tumors such as osteosarcoma and soft tissue sarcoma, melanoma, carcinoma (lung, colorectal, breast, ovarian, hepatocellular and adrenocortical), acute myeloid leukaemia, glioblastoma multiforme andĀ  meduloblastoma. Mebendazole can induce the depolymerization of microtubules in neoplasms and newly formed vasculature, stopping tumor growth and neoangiogenesis, along with other proposed mechanisms of action.Keywords: Anthelmintic, Mebendazole, Cancer treatment, Antimicrotubullar effect, Antineoangiogenesi

    On Some Properties of Silver Iodide

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    In order to obtain the relation between several factors affecting the colloido-chemical properties of silver iodide in the heterogeneous exchange processes, the following measurements were carried out: determination of the adsorption capacity of silver iodide (radiometry) tempered from 20 up to 400 Ā°c, dry aged for 20 days to 5 years, pressed at 500 and 1500 kg cm-2 (on dried isoelectric precipitate); determination of the relation between particle size (electron microscopy) and crystallite size (X-ray diffraction analysis), and of the adsorption capacity of AgI (formed by dilution of KI + AgI complex solution) in the presence of sodium laurylsulphate (SLS); determination of the surface area (BET) of the tempered isoelectric dried silver iodide; determination of particle size and determination of the volume fraction of cubic and hexagonal modifications of AgI in the tempered samples. In conclusion, the effect of the inner surface as a possible relevant factor for the elucidation of the influence of surface active substances on acceleration of the exchange rate is pointed out. Interactions with sodium laurylsulphate are also discussed

    Ecological analysis of aquatic macroinvertebrate communities in three types of running waters in Belgrade region

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    Proučavanjem zajednica akvatičnih makrobeskičmenjaka tekućih voda na području Beograda u periodu 2007-2011. godina zabeleženo je 115 taksona iz 48 porodica, 8 klasa i 5 razdela. Istraživani vodotoci nalaze se pod velikim antropogenim stresom i prema važećem Pravilniku o parametrima ekoloÅ”kog i hemijskog statusa povrÅ”inskih voda i parametrima hemijskog i kvantitativnog statusa podzemnih voda (Službeni glasnik RS 74/2011), svrstani su u tri tipa i to: tip 1, vrlo velike ravničarske reke sa dominacijom finog nanosa ā€“ Dunav i Sava; tip 2, velike reke sa dominacijom srednje krupnog nanosa ā€“ Kolubara; i tip 3, male i srednje velike reke nadmorske visine do 500 m sa dominacijom krupnog nanosa ā€“ Topčiderska i Železnička reka. Istraživanja su vrÅ”ena od 2007. do 2011. godine u periodu visokih voda (maj/jun) i niskih voda (septembar/oktobar). Takođe je koriŔćen i materijal prikupljen u periodu od 1996. do 2000. godine od strane istaživača laboratorije Odeljenja za hidroekologiju i zaÅ”titu voda Instituta za bioloÅ”ka istraživanja "SiniÅ”a Stanković" Univerziteta u Beogradu. U tipu 1 vodotoka na području Beograda zabeležena su 63 taksona u Dunavu i 43 u Savi, sa dominacijom oligoheta. Najveći broj taksona zabeležen je u tipu 2 vodotoka, 78 taksona u Kolubari, sa dominacijom insekatske komponente u zajednici. U tipu 3 vodotoka, u Topčiderskoj i Železničkoj reci, zabeleženo je 25, odnosno 36 taksona, pri čemu je u Topčiderskoj reci dominirala grupa oligoheta, dok su u Železničkoj reci najveći udeo u zajednici imale hironomide. Poređenjem sa rezultatima prethodnih istraživanja, analizirane su promene u sastavu i strukturi zajednica u istraživanim tokovima. Rezultati multivarijantne analize ukazuju da je karakterističnoj distribuciji vrsta u sva tri tipa istraživanih vodotoka u najvećoj meri doprineo hemijski sastav sedimenta. Fizički i hemijski parametri vode su takođe, u velikoj meri, pokazali uticaj na zajednice akvatičnih beskičmenjaka. Uočeno je da je u velikim rekama efikasnije razmatrati vezu zajednice akvatičnih beskičmenjaka i viÅ”emesečne prosečne vrednosti fizičkih i hemijskih parametara vode, dok su u manjim vodotocima bujičnog karaktera trenutno izmerene vrednosti pokazale veći uticaj na zajednice akvatičnih beskičmenjaka...During the survey of the communities of aquatic macroinvertebrates of rivers and streams in Belgrade region 115 taxa from 48 families, 8 classes and 5 phyla were detected. These waterbodies are under a high anthropogenic stress and, based on the Regulation on the parameters of the ecological and chemical status of surface waters and the parameters of the chemical and quantitative status of groundwater (Official Gazette of RS 74/2011), they are classified into three types: Type 1, large lowland rivers with the domination of fine bottom sediments ā€“ the Danube and the Sava River; Type 2, large rivers with the domination of medium sized sediments ā€“ the Kolubara River; and Type 3, small to medium sized rivers at elevation of up to 500 m, with the domination of the hard bottom substrate ā€“ the Topčiderska River and the Železnička River. The research was carried out from 2007 to 2011, in the period of high water levels (May/June) and of low water levels (September/October). Additional material, collected from 1996 to 2000 by researchers from the laboratory of the Department of Aquatic Ecology of the Institute for Biological Research "SiniÅ”a Stanković" of the University of Belgrade, was also included in the analyses. In the Type 1 watercourses in Belgrade region, 63 taxa were recorded in the Danube and 43 in the Sava River, with Oligochaeta as the dominant group. The largest number of taxa were identified in the Type 2 watercourses, 78 taxa in the Kolubara River, with the dominance of the insect component of the community. In the Type 3 watercourses, in the Topčiderska River and the Železnička River, 25 and 36 taxa were recorded, respectively. While Oligochaeta prevailed in the Topčiderska River, Chironomidae were the dominant group in the Železnička River. Changes in the composition and structure of communities in the studied streams were observed following the comparison with the previous findings. The results of a multivariate analysis indicate that the chemical composition of the sediment largely contributed to the characteristic distribution of species in all three investigated watercourses. Physical and chemical parameters of water also showed a significant impact on communities of aquatic invertebrates. Our results suggest that it is more effective to analyse the relation of the average values of chemical parameters across several months and macroinvertebrate assemblages in the case of large rivers, while for smaller size watercourses of torrential character, the current values of chemical parameters were better correlated with these communities and had a greater impact on them..

    Streamlining collection of training samples for object detection and classification in video

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