49 research outputs found

    Min-protein oscillations in Escherichia coli with spontaneous formation of two-stranded filaments in a three-dimensional stochastic reaction-diffusion model

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    We introduce a three-dimensional stochastic reaction-diffusion model to describe MinD/MinE dynamical structures in Escherichia coli. This model spontaneously generates pole-to-pole oscillations of the membrane-associated MinD proteins, MinE ring, as well as filaments of the membrane-associated MinD proteins. Experimental data suggest MinD filaments are two-stranded. In order to model them we assume that each membrane-associated MinD protein can form up to three bonds with adjacent membrane associated MinD molecules and that MinE induced hydrolysis strongly depends on the number of bonds MinD has established.Comment: Corrected typos, changed conten

    3D PRINTED HYDROGEL GLUCOSE SENSOR ON ARGON PLASMA ACTIVATED POLYSTYRENE

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    This study presents a proof of principle concept for a two-dimensional bioprinted glucose sensor on Petri dishes that allows for glucose measurements in cell culture medium. To improve bioink adhesion, the polystyrene surfaces of standard Petri dishes are activated with argon plasma, which increases roughness and hydrophilicity. The bioink containing the sensor chemistry—namely fluorescently labeled ConA/Dextran embedded in alginate microbeads—was printed on the activated Petri dishes with an extrusion-based bioprinter. The printed sensor showed good stability and adhesive properties on polystyrene. The glucose concentration was examined using a standard fluorescence microscope with filters adapted to the emission wavelength of the donor and reference dyes. The printed glucose sensor showed high sensitivity and good linearity in a physiologically relevant range of glucose concentrations

    Health risk assessment of natural and artificial radionuclides in medicinal plants

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    In the present work, we determined activity concentrations of ten Medicinal herbs using gamma spectrometry. The radioactivity concentration of 226 Ra, 232 Th, 40 K and 137 Cs were 2.82, 0.63, 984.32, 0.28 Bq/kg, respectively. These doses are not hazardous to the general public's health. The mean values of radium equivalent activity (Raeq), absorbed dose rates (D), annual effective dose (De) and external hazard index (Hex) are 79.51 Bq/kg, 42.73 nGy-1 , 52.40 µSv and 0.21, respectively. Medicinal plants used to make tea do not contain a concentration of tested radionuclides that would cause negative consequences to one's health.Publishe

    Optimalni rokovi primene fungicida za suzbijanje Podosphaera leucotricha, prouzrokovača rđaste mrežavosti plodova breskve u Srbiji

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    Peach rusty spot has regularly occurred in Serbia in recent years, causing significant economic losses in the production of late maturing cultivars (Summerset, Suncrest, Fayette and O’Henry). Concerns regarding the etiology of this disease have been solved using molecular identification and cross-pathogenicity tests, which have proved that peach rusty spot is caused by Podosphaera leucotricha. The usual recommended strategy for its control, by multiple treatments starting from petal fall phenophase, has not proved satisfactory in agro-ecological conditions in Serbia. After testing the fungicide efficacy, a three-year study was carried out to determine the precise treatment terms and make the control of P. leucotricha more efficient. The investigation was conducted in the conditions of natural infection in a Summerset cultivar orchard at the locality of Bela Crkva, during the period 2006-2008. Nine different variants of both single and mixed treatments were tested, covering six defined peach growth phenophases - from green top, until the phenophase of second fruit falling. In the conditions of high levels of natural infection in the control plots, in all three investigation years the most efficient was the variant in which kresoxim-methyl was applied three times: in green top, pink bud and full bloom phenophases (91.69 - 91.92%), followed by the variant of treatments in the phenophases of rose bud, full bloom and petal fall (86.3-87.87%) and the variant of two treatments, performed in the phenophases of pink bud and full bloom (79.3-83.09%). The other tested variants showed significantly lower efficiency. The results obtained could significantly contribute to better peach fruit production, without losses caused by peach rusty spot which is commercially very important disease in Serbia.Rđasta mrežavost plodova breskve poslednjih godina u Srbiji redovno se javlja i u proizvodnji poznih sorti (Summerset, Suncrest, Fayette i O’Henry) nanoseći značajne ekonomske gubitke. Nedoumice u pogledu etiologije ove bolesti razrešene su na osnovu molekularne identifikacije i unakrsnih testova patogenosti čime je dokazano da rđastu mrežavost breskve izaziva Podosphaera leucotricha. Strategija kontrole P. leucotricha primenjena u svetu, po kojoj suzbijanje treba sprovoditi u višekratnim tretmanima od fenofaze precvetavanja, nije dala zadovoljavajuće rezultate u agroekološkim uslovima Srbije. Nakon izvršenih ispitivanja efikasnosti fungicida, obavljeno je trogodišnje istraživanje u cilju određivanja preciznih rokova tretiranja breskve radi uspostavljanja efikasne kontrole P. leucotricha. Ispitivanje je obavljeno u periodu od 2006. do 2008. godine, u zasadu breskve sorte Summerset, u uslovima prirodne zaraze na lokalitetu Bela Crkva. Testirano je devet različitih varijanti, koje su se sastojale iz kombinovanih i pojedinačnih tretiranja, tako da je pokriven period od šest definisanih fenofaza razvoja breskve, počevši od fenofaze zeleni vrh do fenofaze drugo opadanje plodova. U uslovima visokog nivoa prirodne zaraze u kontrolnim parcelama, najvišu efikasnost u sve tri godine ispitivanja ispoljila je varijanta u kojoj je kresoksim- metil primenjivan tri puta, u fenofazi zeleni vrh, roze pupoljak i cvetanje (91,69-91,92%), odmah zatim varijanta u kojoj su izvođeni tretmani u fenofazi roze pupoljak, cvetanje i precvetavanje (86,3-87,87%) i varijanta u okviru koje su bila vršena dva tretmana u fenofazi roze pupoljak i cvetanje (79,3-83,09%). Ostale varijante u ogledu ispoljile su znatno nižu efikasnost. Dobijeni rezultati značajno doprinose poboljšanom načinu proizvodnje breskve bez gubitaka izazvanih rđastom mrežavosti ploda, ekonomski sve značajnijeg oboljenja u Srbiji

    Electrospun Nickel Manganite (NiMn2O4) Nanocrystalline Fibers for Humidity and Temperature Sensing

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    Nickel manganite nanocrystalline fibers were obtained by electrospinning and subsequent calcination at 400 degrees C. As-spun fibers were characterized by TG/DTA, Scanning Electron Microscopy and FT-IR spectroscopy analysis. X-ray diffraction and FT-IR spectroscopy analysis confirmed the formation of nickel manganite with a cubic spinel structure, while N-2 physisorption at 77 K enabled determination of the BET specific surface area as 25.3 m(2)/g and (BJH) mesopore volume as 21.5 m(2)/g. The material constant (B) of the nanocrystalline nickel manganite fibers applied by drop-casting on test interdigitated electrodes on alumina substrate, dried at room temperature, was determined as 4379 K in the 20-50 degrees C temperature range and a temperature sensitivity of -4.95%/K at room temperature (25 degrees C). The change of impedance with relative humidity was monitored at 25 and 50 degrees C for a relative humidity (RH) change of 40 to 90% in the 42 Hz pi 1 MHz frequency range. At 100 Hz and 25 degrees C, the sensitivity of 327.36 +/- 80.12 k omega/%RH was determined, showing that nickel manganite obtained by electrospinning has potential as a multifunctional material for combined humidity and temperature sensing

    Alginate-derived activated carbon hybridized with NiMn2O4 for use in supercapacitors

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    Transition metal oxides (TMOs) are promising materials because of their specific properties enabling their application in energy solutions, such as their pseudocapacitive behavior enabling utilization as electrode materials in supercapacitors. Activated carbon is a material well known as an electric double layer capacitor (EDLC). Bringing together the two different capacitor materials- TMOs as pseudocapacitors and carbon materials as EDL capacitors is the goal for generating future generation supercapacitors. Nickel manganite is a material of interest because of various oxidation states of manganese which provide its reactivity in oxidoreduction reactions, enhancing the pseudocapacitive behavior. Herein, we synthesized nano-sized nickel manganite by a sol-gel combustion synthesis process using glycine as fuel and subsequent calcination process. The structure and morphology of synthesized material was investigated via XRD, FESEM, and FTIR spectroscopy. Specific surface area and was determined from measured nitrogen desorption/desorption isotherms. Activated carbon was obtained by pyrolytic carbonization of alginate hydrogel in nitrogen atmosphere and activation with KOH. The material was combined with synthesized NiMn2O4 nanopowder and tested as supercapacitor electrode. The second alternative was incorporating NiMn2O4 powder into alginate hydrogel, followed by pyrolysis in nitrogen atmosphere to obtain a NiMn2O4 -activated carbon composite. The obtained materials were electrochemically characterized with cyclic voltammetry (LV) and galvanostatic chronopotentiometry to get galvanostatic charge-discharge curves. We calculated high specific capacitance values ranging to several hundred F/g, showing our hybrid material is a promising electrode in a supercapacitor system

    Antibacterial and cytotoxic activities of naphthoquinone pigments from Onosma visianii Clem

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    In this study, the antibacterial and cytotoxic activities of isolated compounds from the roots of Onosma visianii were investigated. By using different chromatographic techniques and appropriate spectroscopic methods, the seven naphthoquinones were described: deoxyshikonin (1), isobutyrylshikonin (2), α-methylbutyrylshikonin (3), acetylshikonin (4), ß-hydroxyisovalerylshikonin (5), 5,8-O-dimethyl isobutyrylshikonin (6) and 5,8-O-dimethyl deoxyshikonin (7). Among the tested compounds, 3 and 4 exhibited the highest antibacterial activities toward all tested bacterial species (MIC50 and MIC90 for gram positive bacteria: 6.40 µg/mL-12.79 µg/mL and 6.82 µg/mL-13.60 µg/mL, respectively; for gram negative bacteria: 4.27 µg/mL-8.53 µg/mL and 4.77 µg/mL-9.54 µg/mL, respectively). Also, naphthoquinones 3 and 4 exhibited strong cytotoxic activity against MDA-MB-231 cells (IC50 values 86.0 µg/mL and 80.2 µg/mL, respectively), while compounds 1, 3, 4 and 5 significantly decreased viability of HCT116 cells (IC50 values of 97.8 µg/mL, 15.2 µg/mL, 24.6 µg/mL and 30.9 µg/mL, respectively). Our results indicated that all tested naphthoquinone pigments are potential candidates for clinical uses as antibacterial and cytotoxic agents

    Search for long-lived, multi-charged particles in pp collisions at root s=7 TeV using the ATLAS detector

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    A search for highly ionising, penetrating particles with electric charges from vertical bar q vertical bar = 2e to 6e is performed using the ATLAS detector at the CERN Large Hadron Collider. Proton-proton collision data taken at root s = 7 TeV during the 2011 running period, corresponding to an integrated luminosity of 4.4 fb(-1), are analysed. No signal candidates are observed, and 95% confidence level cross-section upper limits are interpreted as mass-exclusion lower limits for a simplified Drell-Yan production model. In this model, masses are excluded from 50 GeV up to 430, 480, 490, 470 and 420 GeV for charges 2e, 3e, 4e, 5e and 6e, respectively. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved

    Measurement of the top quark pair production cross section in pp collisions at root s=7 TeV in dilepton final states with ATLAS

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    A measurement of the production cross section of top quark pairs (t (t) over bar) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider is reported. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. Using a data sample corresponding to an integrated luminosity of 35 pb(-1), a t (t) over bar production cross section sigma(t (t) over bar) = 177 +/- 20(stat.) +/- 14(syst.) +/- 7(lum.) pb is measured for an assumed top quark mass of m(t) = 172.5 GeV. A second measurement requiring at least one jet identified as coming from a b quark yields a comparable result, demonstrating that the dilepton final states are consistent with being accompanied by b-quark jets. These measurements are in good agreement with Standard Model predictions. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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