147 research outputs found

    Possible background reductions in double beta decay experiments

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    The background induced by radioactive impurities of 208Tl^{208}\rm Tl and 214Bi^{214}\rm Bi in the source of the double beta experiment NEMO-3 has been investigated. New methods of data analysis which decrease the background from the above mentioned contamination are identified. The techniques can also be applied to other double beta decay experiments capable of measuring independently the energies of the two electrons.Comment: 15 pages, 13 figures, accepted in the Nuclear Instruments and Methods

    Probing New Physics Models of Neutrinoless Double Beta Decay with SuperNEMO

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    The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double beta decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double beta decay by measuring the decay half-life and the electron angular and energy distributions.Comment: 17 pages, 14 figures, to be published in E.P.J.

    Cyclodextrin modulation of gallic acid in vitro antibacterial activity

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    The substitution of large spectrum antibiotics for natural bioactive molecules (especially polyphenolics) for the treatment of wound infections has come into prominence in the pharmaceutical industry. However, the use of such molecules depends on their stability during environmental stress and on their ability to reach the action site without losing biological properties. The application of cyclodextrins as a vehicle for polyphenolics protection has been documented and appears to enhance the properties of bioactive molecules. Therefore, the encapsulation of gallic acid, an antibacterial agent with low stability, by -cyclodextrin, (2-hydroxy) propyl--cyclodextrin and methyl--cyclodextrin, was investigated. Encapsulation by -cyclodextrin was confirmed for pH 3 and 5, with similar stability parameters. The (2-hydroxy) propyl--cyclodextrin and methyl--cyclodextrin interactions with gallic acid were only confirmed at pH 3. Among the three cyclodextrins, better gallic acid encapsulation were observed for (2-hydroxy) propyl--cyclodextrin, followed by -cyclodextrin and methyl--cyclodextrin. The effect of cyclodextrin encapsulation on the gallic acid antibacterial activity was also analysed. The antibacterial activity of the inclusion complexes was investigated here for the first time. According to the results, encapsulation of gallic acid by (2-hydroxy) propyl--cyclodextrin seems to be a viable option for the treatment of skin and soft tissue infections, since this inclusion complex has good stability and antibacterial activity.The authors are grateful for the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project "BioHealth-Biotechnology and Bioengineering approaches to improve health quality", Ref. NORTE-07-0124-FEDER-000027, co-funded by the "Programa Operacional Regional do Norte" (ON.2-O Novo Norte), QREN, FEDER. The authors also acknowledge the project "Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB", Ref. FCOMP-01-0124-FEDER-027462. This work is, also, funded by FEDER funds through the Operational Programme for Competitiveness Factors-COMPETE and National Funds through FCT-Foundation for Science and Technology under the project PEst-C/CTM/UI0264/2011. Additionally, the authors would like to thank the FCT for the grant for E. Pinho (SFRH/BD/62665/2009)

    Limits on different Majoron decay modes of 100^{100}Mo and 82^{82}Se for neutrinoless double beta decays in the NEMO-3 experiment

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    The NEMO-3 tracking detector is located in the Fr\'ejus Underground Laboratory. It was designed to study double beta decay in a number of different isotopes. Presented here are the experimental half-life limits on the double beta decay process for the isotopes 100^{100}Mo and 82^{82}Se for different Majoron emission modes and limits on the effective neutrino-Majoron coupling constants. In particular, new limits on "ordinary" Majoron (spectral index 1) decay of 100^{100}Mo (T1/2>2.71022T_{1/2} > 2.7\cdot10^{22} y) and 82^{82}Se (T1/2>1.51022T_{1/2} > 1.5\cdot10^{22} y) have been obtained. Corresponding bounds on the Majoron-neutrino coupling constant are <(0.41.9)104 < (0.4-1.9) \cdot 10^{-4} and <(0.661.7)104< (0.66-1.7) \cdot 10^{-4}.Comment: 23 pages includind 4 figures, to be published in Nuclear Physics

    Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors

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    We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of 207Bi\rm ^{207}Bi and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.Comment: 16 pages, 10 figure

    Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils

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    The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in 208^{208}Tl and 214^{214}Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 m2m^2 of sensitive surface area, has been running in the Modane Underground Laboratory since February, 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in 208^{208}Tl. After more than one year of background measurement, a surface activity of the scintillators of A\mathcal{A}(208^{208}Tl) == 1.5 μ\muBq/m2^2 is reported here. Given this level of background, a larger BiPo detector having 12 m2^2 of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A\mathcal{A}(208^{208}Tl) << 2 μ\muBq/kg (90% C.L.) with a six month measurement.Comment: 24 pages, submitted to N.I.M.

    Investigation of Linum flavum (L.) Hairy Root Cultures for the Production of Anticancer Aryltetralin Lignans.

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    Collaboration with: Université d’Orléans, 28000 Chartres, France, Université de Picardie Jules Verne, F-80037 Amiens, France De Montfort University Open access articleLinum flavum hairy root lines were established from hypocotyl pieces using Agrobacterium rhizogenes strains LBA 9402 and ATCC 15834. Both strains were effective for transformation but induction of hairy root phenotype was more stable with strain ATCC 15834. Whereas similar accumulation patterns were observed in podophyllotoxin-related compounds (6-methoxy-podophyllotoxin, podophyllotoxin and deoxypodophyllotoxin), significant quantitative variations were noted between root lines. The influence of culture medium and various treatments (hormone, elicitation and precursor feeding) were evaluated. The highest accumulation was obtained in Gamborg B5 medium. Treatment with methyl jasmonate, and feeding using ferulic acid increased the accumulation of aryltetralin lignans. These results point to the use of hairy root culture lines of Linum flavum as potential sources for these valuable metabolites as an alternative, or as a complement to Podophyllum collected from wild stands

    Analysis of additivity and synergism in the anti-plasmodial effect of purified compounds from plant extracts

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    In the search for antimalarials from ethnobotanical origin, plant extracts are chemically fractionated and biological tests guide the isolation of pure active compounds. To establish the responsibility of isolated active compound(s) to the whole antiplasmodial activity of a crude extract, the literature in this field was scanned and results were analysed quantitatively to find the contribution of the pure compound to the activity of the whole extract. It was found that, generally, the activity of isolated molecules could not account on their own for the activity of the crude extract. It is suggested that future research should take into account the “drugs beside the drug”, looking for those products (otherwise discarded along the fractionation process) able to boost the activity of isolated active compounds

    Roflumilast in moderate-to-severe chronic obstructive pulmonary disease treated with longacting bronchodilators: two randomised clinical trials

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    Background Patients with chronic obstructive pulmonary disease (COPD) have few options for treatment. The efficacy and safety of the phosphodiesterase-4 inhibitor roflumilast have been investigated in studies of patients with moderate-to-severe COPD, but not in those concomitantly treated with longacting inhaled bronchodilators. The effect of roflumilast on lung function in patients with COPD that is moderate to severe who are already being treated with salmeterol or tiotropium was investigated. Methods In two double-blind, multicentre studies done in an outpatient setting, after a 4-week run-in, patients older than 40 years with moderate-to-severe COPD were randomly assigned to oral roflumilast 500 mu g or placebo once a day for 24 weeks, in addition to salmeterol (M2-127 study) or tiotropium (M2-128 study). The primary endpoint was change in prebronchodilator forced expiratory volume in 1s (FEV(1)). Analysis was by intention to treat. The studies are registered with ClinicalTrials.gov, number NCT00313209 for M2-127, and NCT00424268 for M2-128. Findings In the salmeterol plus roflumilast trial, 466 patients were assigned to and treated with roflumilast and 467 with placebo; in the tiotropium plus roflumilast trial, 371 patients were assigned to and treated with roflumilast and 372 with placebo. Compared with placebo, roflumilast consistently improved mean prebronchodilator FEV(1) by 49 mL (p<0.0001) in patients treated with salmeterol, and 80 mL (p<0.0001) in those treated with tiotropium. Similar improvement in postbronchodilator FEV(1) was noted in both groups. Furthermore, roflumilast had beneficial effects on other lung function measurements and on selected patient-reported outcomes in both groups. Nausea, diarrhoea, weight loss, and, to a lesser extent, headache were more frequent in patients in the roflumilast groups. These adverse events were associated with increased patient withdrawal. Interpretation Roflumilast improves lung function in patients with COPD treated with salmeterol or tiotropium, and could become an important treatment for these patients

    Measurement of the 2νββ decay half-life of 150Nd and a search for 0νββ decay processes with the full exposure from the NEMO-3 detector

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    We present results from a search for neutrinoless double-β (0νββ) decay using 36.6 g of the isotope 150Nd with data corresponding to a live time of 5.25 y recorded with the NEMO-3 detector. We construct a complete background model for this isotope, including a measurement of the two-neutrino double-β decay half-life of T2ν 1=2 ¼ ½9.34 0.22ðstatÞ þ0.62 −0.60 ðsystÞ × 1018 y for the ground state transition, which represents the most precise result to date for this isotope. We perform a multivariate analysis to search for 0νββ decays in order to improve the sensitivity and, in the case of observation, disentangle the possible underlying decay mechanisms. As no evidence for 0νββ decay is observed, we derive lower limits on half-lives for several mechanisms involving physics beyond the standard model. The observed lower limit, assuming light Majorana neutrino exchange mediates the decay, is T0ν 1=2 > 2.0 × 1022 y at the 90% C.L., corresponding to an upper limit on the effective neutrino mass of hmνi < 1.6–5.3 eV
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