Numerical study of transient three-dimensional heat conduction problem with a moving heat source

A numerical study of transient three-dimensional heat conduction problem with a moving source is presented. For numerical solution Douglas-Gunn alternating direction implicit method is applied and for the moving heat source flux distribution Gaussian function is used. An influence on numerical solution of input parameters figuring in flux boundary conditions is examined. This include parameters appearing in Gaussian function and heat transfer coefficient from free convection boundaries. Sensitivity of cooling time from 800 to 500°C with respect to input parameters is also tested

Numerical analysis of temperature field during hardfacing process and comparison with experimental results

The three-dimensional transient nonlinear thermal analysis of the hard facing process is performed by using the finite element method. The simulations were executed on the open source Salome platform using the open source finite element solver Code_Aster. The Gaussian double ellipsoid was selected in order to enable greater possibilities for the calculation of the moving heat source. The numerical results were compared with available experimental results

alpha-Glucosidase inhibitory activity and cytotoxic effects of some cyclic urea and carbamate derivatives

The inhibitory activities of selected cyclic urea and carbamate derivatives (1-13) toward alpha-glucosidase (alpha-Gls) in in vitro assay were examined in this study. All examined compounds showed higher inhibitory activity (IC50) against alpha-Gls compared to standard antidiabetic drug acarbose. The most potent was benzyl (3,4,5-trimethoxyphenyl) carbamate (12) with IC50 = 49.85 +/- 0.10 mu M. In vitro cytotoxicity of the investigated compounds was tested on three human cancer cell lines HeLa, A549 and MDA-MB-453 using MTT assay. The best antitumour activity was achieved with compound 2 (trans-5-phenethyl-1-phenylhexahydro-1H-imidazo[4,5-c] pyridin-2(3H)-one) against MDA-MB-453 human breast cancer cell line (IC50 = 83.41 +/- 1.60 mu M). Cyclic ureas and carbamates showed promising anti-alpha-glucosidase activity and should be further tested as potential antidiabetic drugs. The PLS model of preliminary QSAR study indicated that, in planing the future synthesis of more potent compounds, the newly designed should have the substituents capable of polar interactions with receptor sites in various positions, while avoiding the increase of their lipophilicity

Leaching kinetics of Cs+ and Co2+ under dynamic conditions

The possibility of retaining Cs+ and Co2+ bound by immobilization processes in the cement matrix is defined as the subject of its investigation: the cement matrix formulation, the water/ cement ratio, the amount of waste, and the porosity of such a structure. Implementing the standard leaching method by Hespe the possibility of comparing different authors’ results was achieved. Diffusion and semi-empirical model were used to investigate the transport phenomenon in order to predict the leaching level for a long period of time. Leaching of Co2+ and Cs+ ions under dynamic conditions immobilized in the cement matrix dynamic conditions decreases with the increase of the sludge content, regarding porosity increase. The effects of the diffusion and surface washing are equalized, and the contribution ofthe matrix dissolution to the Cs + and Co2+ transport in the cement porous media increases, on average, for one order of magnitude. The semi-empirical model gives a better approximation for Co2+ and Cs+ leaching process for the duration ofthe experiment while both models significantly approximate leaching results in dynamic conditions. © 2019, Vinca Inst Nuclear Sci. All rights reserved

Is There a Possibility to Involve the Hormesis Effect on the Soybean with Glyphosate Sub-Lethal Amounts Used to Control Weed Species Amaranthus retroflexus L.?

Sub-lethal doses of herbicides can promote plant growth and have a positive effect on an organism this is called hormesis. The purpose of this study was to test the effects of sub-lethal doses of glyphosate on soybean (Glycine max(L.) Merr.) (1.8, 3.6, 7.2, 36, 180, and 720 g ha(-1)) and Amaranthus retroflexus L. (7.2, 36, 180, 720, 1440, and 2880 g ha(-1)). Different biological parameters, such as phytotoxicity, fresh weight, root length, content of photosynthetic pigments, and shikimate concentration, were measured. Glyphosate in doses of 1440 and 2880 g ha(-1) destroyed A. retroflexus plants. A fresh weight of A. retroflexus at a dose of 36 g ha(-1) was reduced by 76.31%, while for the soybean it was reduced by 19.26%. At the highest dose, the shikimate concentration was 145% in the soybean, while in A. retroflexus, the concentration increased by 58.80% compared to the control plants. All doses of glyphosate were statistically significantly different in terms of chlorophyll a content, while higher doses in A. retroflexus caused chlorophyll b to decrease. The change in the production of carotenoids was not statistically significant. The results showed that sub-lethal amounts of glyphosate did not lead to stimulation of measured parameters of soybean

Kultivacija matičnih i progenitorskih ćelija hematopoeze iz kostne srži hrčka

Hamster, a hibernating animal, is an important experimental model in research on the influence of hypothermia on different physiological processes. A simple procedure for cultivation and identification of hamster hematopoetic stem cells (HSC) and hematopoetic progenitor cells (HPC) is a premise for a successful investigation upon hypothermia effects on hematopoiesis. The aim of this work was to evaluate the utilization of commercially available methylcellulose media (MC) and recombinant mouse and human cytokines for hamster HSC and HPC assays, in order to enable further studies on these cells. Hamster bone marrow mononuclear cells (BMMNC) were plated in MC containing cytokines that support mouse or human HPC growth. Also, BMMNC were resuspended in cytokine supplemented liquid media and incubated for 5 weeks with a four day monitoring of viable cell number. We demonstrated that hamster hematopoietic progenitor cells committed for erythroid lineage and myeloid lineage successfully formed recognizable colonies in both mouse and human MC, while multipotent progenitor cells formed colonies only in mouse MC. We also defined conditions for the evaluation of hamster HSC activity in liquid cultures, based on continuous 5 weeks HSC proliferation. The obtained results verify the utilization of mouse specific MC for further research on hamster HPC biology during hypothermia.Fiziološka hibernacija u koju hrčci ulaze prilikom izlaganja niskim temperaturama, čini ove životinje zanimljivim eksperimentalnim modelom za ispitivanje hematopoeze u uslovima hipotermije. Preduslov za ovo ispitivanje je postojanje jednostavne metode za kultivaciju i identifikaciju hematopoetskih ćelija hrčka. Cilj ovog rada je bio da se ispita mogućnost kultivacije progenitorskih ćelija hematopoeze hrčka u kompletnoj metil celulozi dizajniranoj za kultivaciju mišijih i humanih hematopoetskih ćelija, kao i da se odrede optimalni uslovi za kultivaciju matičnih ćelija hematopoeze hrčka u tečnoj kulturi. Mononuklearne ćelije kostne srži hrčka su posađene u metil celulozu i u tečnu kulturu. Oba medijuma su sadržala kombinacije rekombinantnih mišijih i/ili humanih citokina. Kolonije progenitorskih ćelija opredeljenih za mijelopoezu i opredeljenih za eritropoezu su se formirale u metil celulozi dizajniranoj za kultivaciju mišijih i humanih hematopoetskih ćelija, dok su se primitivnije kolonije sastavljene od oba tipa ćelija (mijeloidna i eritrocitna loza) formirale samo u metil celulozi dizajniranoj za kultivaciju mišijih hematopoetskih ćelija. Osim toga, populacija matičnih ćelija hematopoeze hrčka je proliferisala u tečnim kulturama tokom 5 nedelja bez znakova opadanja proliferativnog potencijala. Ova istraživanja pokazuju da se primenjene metode mogu uspešno koristiti za ispitivanje hematopoeze kod hrčka

The Application of Experimental Design Methodology for the Investigation of Liquid Radioactive Waste Treatment

The sorption properties of waste facade, brick, and asphalt sample towards Sr(II), Co(II), and Ni(II) ions from single and multicomponent solutions were investigated. The highest sorption capacity was found for Ni(II) ions, while the most effective sorbent was facade. Simplex Centroid Mixture Design was used in order to investigate the sorption processes of ions from solutions with different composition as well as the competition between the cations. Based on the statistical analysis results, the equations for data modeling were proposed. According to the observations, the investigated solid matrices can be effectively used for the liquid radioactive waste treatment. Furthermore, the applied methodology turned out to be an easy and operational way for the investigations of multicomponent sorption processes

The metalanguage of a lexicographic definition in the descriptive dictionary (based on the dictionaries of the Serbian language)

In this paper we present the continuous hierarchical ordering of the first part of the definition of lexemes from the thematic group ‘buildings’ by analyzing the vertical organization of superordination of concepts in the lexicographical definition. We demonstrate that the vertical sequence mounts from a higher level of conceptual categorization, ‘localizer,’ in the form of complex and simple primitives (PLACE > SPACE [WHERE], SPACE > EXPANSE [SOMETHING THAT IS (BOUNDLESSLY) SPREADING IN EVERY DIRECTION]) and descends toward a lower hyperonimic level of ‘buildings’. The suggested model links meanings systematically, on a micro-level of meaning within the polysemic structure, and on a macrolevel of meanings of lexemes belonging to a thematic group/class, which is significant for the descriptive lexicography and for the modeling of semantic description in the electronic dictionary of the contemporary Serbian language. Such description could facilitate the cross-referencing of lexemes and advanced search, which is essential both for linguists and dictionary users.[Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 178009: Lingvistička istraživanja savremenog srpskog jezika i izrada Rečnika srpskohrvatskog književnog i narodnog jezika SANU

The influence of equilibration conditions and hydroxyapatite physico-chemical properties onto retention of Cu2+ ions

The influence of equilibration conditions and hydroxyapatite (HAP) physico-chemical properties onto retention of Cu2+ ions was studied in batch conditions. The amount of cation removed from the solution increased with increasing pH, reaching almost 100% at pH 3. 4 and 7 for 5 x 10(-4), 10(-3) and 5 x 10(-3) mol/dm(3) solutions. respectively. Contact time necessary for reaching equilibrium was found to increase with the increase of Cu2+ concentration. Kinetic and equilibrium data were best described by pseudo-second-order kinetic model and Langmuir theoretical model. The calculated values of separation factors and Gibbs free energy change confirmed that the sorption was spontaneous and thermodynamically feasible at room temperature. The experiments conducted using HAP samples with different physico-chemical characteristics have revealed that the amounts of sorbed Cu2+ depended mainly on the specific surface area and crystallinity of the applied powders. Desorption of Cu2+ was more efficient in acidic conditions than in the Solution of competing cation-Ca2+. The samples with higher sorption capacities also demonstrated higher stability; consequently, from the aspects of both higher sorption and lower desorption, utilization of low-crystalline HAP samples with high specific surface area was superior for immobilization of Cu2+ ions. Taking into account molar Cu/Ca ratios. observed final pH changes, copper speciation in the function of pH and the results of X-ray diffraction analyses, conclusions about sorption mechanisms at different experimental conditions were derived. (C) 2008 Elsevier B.V. All rights reserved