12 research outputs found
A comparison between characterization and biological properties of brazilian fresh and aged propolis
As propolis is a highly valued bee product, we aimed to verify the quality of aged propolis, investigating their phenolic and flavonoid composition, levels of toxic metals, radical scavenging and antimicrobial activities. Samples of fresh and aged propolis of six different beekeepers, from the same geographical location, were investigated in terms of their phenolic and flavonoid composition and levels of Pb, Cd, and Cr, as well as radical scavenging and antimicrobial activities. The two groups of propolis had similar qualitative composition by HPLC-PDA and ESI(-)-MS. Fresh propolis and aged propolis show no differences when average values of extraction yield, flavonoids, EC50, or MIC were compared and both types of propolis showed good antimicrobial activity at low concentrations. Only levels of phenolic compounds were higher in fresh propolis. The propolis samples considered in this study, aged or fresh, had similar qualitative composition, although they were collected in different periods. Samples only differed in their levels of total phenolic content. Moreover, aged propolis conserves significant radical scavenging and antimicrobial properties. We suggest that aged propolis should not be discarded but explored for alternative applications.As propolis is a highly valued bee product, we aimed to verify the quality of aged propolis, investigating their phenolic and flavonoid composition, levels of toxic metals, radical scavenging and antimicrobial activities. Material and Methods. Samples of2014FINEP - FINANCIADORA DE ESTUDOS E PROJETOSCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICOFAPESP - FUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULOFA - FUNDAĂĂO ARAUCĂRIA DE APOIO AO DESENVOLVIMENTO CIENTĂFICO E TECNOLĂsem informaçãosem informaçãosem informação10908/PPP/2006sem informaçãoThe study had financial support by Financiadora de Estudos e projetos (FINEP), Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq), Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP), Fundação AraucĂĄria (10908/PPP/2006), and P
Measurement of ZZ production in leptonic final states at {\surd}s of 1.96 TeV at CDF
In this paper we present a precise measurement of the total ZZ production
cross section in pp collisions at {\surd}s= 1.96 TeV, using data collected with
the CDF II detector corresponding to an integrated luminosity of approximately
6 fb-1. The result is obtained by combining separate measurements in the
four-charged (lll'l'), and two-charged-lepton and two-neutral-lepton (llvv)
decay modes of the Z. The combined measured cross section for pp {\to} ZZ is
1.64^(+0.44)_(-0.38) pb. This is the most precise measurement of the ZZ
production cross section in 1.96 TeV pp collisions to date.Comment: submitted to Phys. Rev. Let
Measurement of b hadron lifetimes in exclusive decays containing a J/psi in p-pbar collisions at sqrt(s)=1.96TeV
We report on a measurement of -hadron lifetimes in the fully reconstructed
decay modes B^+ -->J/Psi K+, B^0 --> J/Psi K*, B^0 --> J/Psi Ks, and Lambda_b
--> J/Psi Lambda using data corresponding to an integrated luminosity of 4.3
, collected by the CDF II detector at the Fermilab Tevatron. The
measured lifetimes are B^+ = , B^0 = and Lambda_b = . The lifetime ratios are B^+/B^0 = and Lambda_b/B^0 = . These are the most precise determinations
of these quantities from a single experiment.Comment: revised version. accepted for PRL publicatio
Search for High Mass Resonances Decaying to Muon Pairs in root s=1.96 TeV p(p)over-bar Collisions
We present a search for a new narrow, spin-1, high mass resonance decaying to mu(+)mu(-) + X, using a matrix-element-based likelihood and a simultaneous measurement of the resonance mass and production rate. In data with 4.6 fb(-1) of integrated luminosity collected by the CDF detector in p (p) over bar collisions at root s = 1960 GeV, the most likely signal cross section is consistent with zero at 16% confidence level. We therefore do not observe evidence for a high mass resonance and place limits on models predicting spin-1 resonances, including M > 1071 GeV/c(2) at 95% confidence level for a Z' boson with the same couplings to fermions as the Z boson
Measurement of b Hadron Lifetimes in Exclusive Decays Containing a J/Psi in p(p)over-bar Collisions at root s=1.96 TeV
We report on a measurement of b-hadron lifetimes in the fully reconstructed decay modes B+-> J/psi K+, B-0 -> J/psi K*(892)(0), B-0 -> J/psi K-s(0), and Lambda(0)(b)-> J/psi Lambda(0) using data corresponding to an integrated luminosity of 4.3 fb(-1), collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are tau(B+)=[1.639 +/- 0.009(stat)+/- 0.009(syst)]ps, tau(B-0)=[1.507 +/- 0.010(stat)+/- 0.008(syst)]ps, and tau(Lambda(0)(b))=[1.537 +/- 0.045(stat)+/- 0.014(syst)]ps. The lifetime ratios are tau(B+)/tau(B-0)=[1.088 +/- 0.009(stat)+/- 0.004(syst)] and tau(Lambda(0)(b))/tau(B-0)=[1.020 +/- 0.030(stat)+/- 0.008(syst)]. These are the most precise determinations of these quantities from a single experiment
An upper limit on the stochastic gravitational-wave background of cosmological origin
A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved gravitational-wave sources of astrophysical and cosmological origin. It should carry unique signatures from the earliest epochs in the evolution of the Universe, inaccessible to standard astrophysical observations1. Direct measurements of the amplitude of this background are therefore of fundamental importance for understanding the evolution of the Universe when it was younger than one minute. Here we report limits on the amplitude of the stochastic gravitational-wave background using the data from a two-year science run of the Laser Interferometer Gravitational-wave Observatory2 (LIGO). Our result constrains the energy density of the stochastic gravitational-wave background normalized by the critical energy density of the Universe, in the frequency band around 100 Hz, to be <6.9 10-6 at 95% confidence. The data rule out models of early Universe evolution with relatively large equation-of-state parameter3, as well as cosmic (super)string models with relatively small string tension4 that are favoured in some string theory models5. This search for the stochastic background improves on the indirect limits from Big Bang nucleosynthesis1, 6 and cosmic microwave background7 at 100 Hz