367 research outputs found

    Lysine blockage of milk proteins in infant formula impairs overall protein digestibility and peptide release

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    During heat processing of milk and dairy products, for example infant formula, the Maillard reaction occurs. In vitro and animal studies suggest that Maillard reaction induced lysine blockage impairs protein digestibility. Most studies that investigate the effect of glycation on protein digestion use a mixture of isolated milk protein with reducing sugars. In this study, infant formulas with 6.5%, 8.4%, 11.2%, 14.8%, 20.8%, and 44.5% of blocked lysine (BL) were digested in an in vitro infant digestion model and tested for protein hydrolysis and peptide release. OPA (o-phthalaldehyde) assay was used to assess the degree of protein hydrolysis. SDS-PAGE was conducted to monitor the hydrolysis of specific proteins. Peptides formed after gastric and intestinal digestion were identified by LC/MS. Protein hydrolysis of the 6.5% BL sample was significantly higher after 10 minutes of intestinal digestion compared to all other samples. Most differences were observed after intestinal digestion. A significant change in peptide patterns was observed for the 45% BL sample resulting in a relatively higher number of peptides with more than 14 amino acids. Mainly casein-derived peptides were affected. Overall, the average peptide length was significantly increased for the 44.5% BL glycated product (on average 10.2 amino acids for 6-21% BL vs. 11.4 amino acids for 45% BL; p < 0.001). In conclusion, glycation of milk proteins in an infant formula product can impair overall protein digestibility. These findings emphasize the importance of mild processing and having low BL levels in infant formula to ensure optimal digestion of proteins.</p

    Correlation gap in the heavy-fermion antiferromagnet UPd_2Al_3

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    The optical properties of the heavy-fermion compound UPd2_2Al3_3 have been measured in the frequency range from 0.04 meV to 5 meV (0.3 to 40 cm1^{-1}) at temperatures 2K<T<3002 {\rm K}<T< 300 K. Below the coherence temperature T50T^*\approx 50 K, the hybridization gap opens around 10 meV. As the temperature decreases further (T20T\leq 20 K), a well pronounced pseudogap of approximately 0.2 meV develops in the optical response; we relate this to the antiferromagnetic ordering which occurs below TN14T_N\approx 14 K. The frequency dependent mass and scattering rate give evidence that the enhancement of the effective mass mainly occurs below the energy which is associated to the magnetic correlations between the itinerant and localized 5f electrons. In addition to this correlation gap, we observe a narrow zero-frequency conductivity peak which at 2 K is less than 0.1 meV wide, and which contains only a fraction of the delocalized carriers. The analysis of the spectral weight infers a loss of kinetic energy associated with the superconducting transition.Comment: RevTex, 15 pages, 7 figure

    First Observation of Coherent π0\pi^0 Production in Neutrino Nucleus Interactions with Eν<E_{\nu}< 2 GeV

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    The MiniBooNE experiment at Fermilab has amassed the largest sample to date of π0\pi^0s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of π0\pi^0s produced in mineral oil (CH2_2) and the first observation of coherent π0\pi^0 production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 ±\pm1.1 (stat) ±\pm2.5 (sys))% of all exclusive NC π0\pi^0 production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for νμνe\nu_{\mu} \to \nu_e oscillations.Comment: Submitted to Phys. Lett.

    Search for Λc+pK+π\Lambda_c^+ \to p K^+ \pi^- and Ds+K+K+πD_s^+ \to K^+ K^+ \pi^- Using Genetic Programming Event Selection

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    We apply a genetic programming technique to search for the double Cabibbo suppressed decays Λc+pK+π\Lambda_c^+ \to p K^+ \pi^- and Ds+K+K+πD_s^+ \to K^+ K^+ \pi^-. We normalize these decays to their Cabibbo favored partners and find BR(\text{BR}(\Lambda_c^+ \to p K^+ \pi^-)/BR()/\text{BR}(\Lambda_c^+ \to p K^- \pi^+)=(0.05±0.26±0.02)) = (0.05 \pm 0.26 \pm 0.02)% and BR(\text{BR}(D_s^+ \to K^+ K^+ \pi^-)/BR()/\text{BR}(D_s^+ \to K^+ K^- \pi^+)=(0.52±0.17±0.11)) = (0.52\pm 0.17\pm 0.11)% where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find <0.46< 0.46 % and <0.78 < 0.78% respectively. This is the first successful use of genetic programming in a high energy physics data analysis.Comment: 10 page

    Post-harvest quality of fresh-marketed tomatoes as a function of harvest periods

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    Losses on tomato business chain start at harvest, a two-months period. At the beginning of the harvest, fruits concentrate at the basal part of the plant, then in the middle, and finally at the top, and undergo changes in diameter and maturity indexes as harvest progresses. The aim of this work was to evaluate the impact of handling at three different periods: (I) 15 days, (II) 30 days, and (III) 45 days after the beginning of harvest. Tomatoes were ordinarily grown and harvested in to bamboo baskets, and transferred to plastics boxes. Fruits were classified according to ripening stage and diameter, and evaluated for mechanical damage and external defects caused by harvesting procedures. The time required for the harvest operation was measured; damage to fruits (%) and weight loss (%), caused either in the field and/or during the harvesting process, were taken into consideration and related to the final quality of fruit after storage for 21 days. The same methodology was used all through the production and harvest cycle. The highest % fruit damage occurred during period II, a longer harvest time than the other two periods. Fruits not submitted to handling showed lower weight loss than handled fruits. Fruits harvested in period II and stored for 21 days showed higher losses due to mechanical injury

    A Non-parametric Approach to the D+ to K*0bar mu+ nu Form Factors

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    Using a large sample of D+ -> K- pi+ mu+ nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first measurements of the helicity basis form factors free from the assumption of spectroscopic pole dominance. We also present the first information on the form factor that controls the s-wave interference discussed in a previous paper by the FOCUS collaboration. We find reasonable agreement with the usual assumption of spectroscopic pole dominance and measured form factor ratios.Comment: 14 pages, 5 figures, and 2 tables. We updated the previous version by changing some words, removing one plot, and adding two tables. These changes are mostly stylisti

    Dalitz plot analysis of D_s+ and D+ decay to pi+pi-pi+ using the K-matrix formalism

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    FOCUS results from Dalitz plot analysis of D_s+ and D+ to pi+pi-pi+ are presented. The K-matrix formalism is applied to charm decays for the first time to fully exploit the already existing knowledge coming from the light-meson spectroscopy experiments. In particular all the measured dynamics of the S-wave pipi scattering, characterized by broad/overlapping resonances and large non-resonant background, can be properly included. This paper studies the extent to which the K-matrix approach is able to reproduce the observed Dalitz plot and thus help us to understand the underlying dynamics. The results are discussed, along with their possible implications on the controversial nature of the sigma meson.Comment: To be submitted to Phys.Lett.B A misprint corrected in formula

    Measurement of the branching ratio of the decay D^0 -> \pi^-\mu^+\nu relative to D^0 -> K^-\mu^+\nu

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    We present a new measurement of the branching ratio of the Cabibbo suppressed decay D^0\to \pi^-\mu^+\nu relative to the Cabibbo favored decay D^0\to K^-\mu^+\nu and an improved measurement of the ratio |\frac{f_+^{\pi}(0)}{f_+^{K}(0)}|. Our results are 0.074 \pm 0.008 \pm 0.007 for the branching ratio and 0.85 \pm 0.04 \pm 0.04 \pm 0.01 for the form factor ratio, respectively.Comment: 13pages, 3 figure
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