893 research outputs found

    Mice lacking C1q or C3 show accelerated rejection of minor H disparate skin grafts and resistance to induction of tolerance

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    Complement activation is known to have deleterious effects on organ transplantation. On the other hand, the complement system is also known to have an important role in regulating immune responses. The balance between these two opposing effects is critical in the context of transplantation. Here, we report that female mice deficient in C1q (C1qa(−/−)) or C3 (C3(−/−)) reject male syngeneic grafts (HY incompatible) at an accelerated rate compared with WT mice. Intranasal HY peptide administration, which induces tolerance to syngeneic male grafts in WT mice, fails to induce tolerance in C1qa(−/−) or C3(−/−) mice. The rejection of the male grafts correlated with the presence of HY D(b)Uty-specific CD8(+) T cells. Consistent with this, peptide-treated C1qa(−/−) and C3(−/−) female mice rejecting male grafts exhibited more antigen-specific CD8(+)IFN-γ(+) and CD8(+)IL-10(+) cells compared with WT females. This suggests that accumulation of IFN-γ- and IL-10-producing T cells may play a key role in mediating the ongoing inflammatory process and graft rejection. Interestingly, within the tolerized male skin grafts of peptide-treated WT mice, IFN-γ, C1q and C3 mRNA levels were higher compared to control female grafts. These results suggest that C1q and C3 facilitate the induction of intranasal tolerance

    On the Effect of Corrosion Defects in the Collapse Pressure of Pipelines

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    ABSTRACT The loss of metal in a pipeline due to corrosion usually results in localized pits with various depths and irregular shapes on its external and internal surfaces. The effect of external corrosion defects was studied via a series of small-scale experiments and through a nonlinear numerical model based on the finite element method. After calibrated in view of the experimental results, the model was used to determine the collapse pressure as a function of material and geometric parameters of different pipes and defects

    Optimization of Supercritical Carbon Dioxide Extraction of Rice Bran Oil and γ-Oryzanol Using Multi-Factorial Design of Experiment

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    After rice harvesting, the milling processes generate many by-products including husk, bran, germs, and broken rice representing around 40% of the total grain. Bran, one of the external cereal layers, contains proteins, dietary fibers, minerals, and lipids. One of the most common rice bran utilization is the extraction of rice bran oil (RBO). Among all vegetable oils, RBO presents a unique chemical composition rich in antioxidant compounds such as γ-oryzanol that provide several beneficial properties. RBO is generally extracted by exploiting hexane, a solvent toxic to the environment and human health. The growing demand for this oil has led researchers to look for more sustainable extraction techniques. Supercritical carbon dioxide (SC-CO2) has been successfully applied to extract oil and functional compounds from several matrices. In this work, the SC-CO2 extraction of RBO was optimized using a Design of Experiment (DoE) on a pilot scale. "The DoE approach involving multilinear regression allowed modelling the yield in RBO and gamma oryzanol as a function of temperature and pressure, keeping the extraction time constant, as decided by the company. This approach made it possible to optimize the extraction yield and to identify the best temperature (40 °C), while also highlighting that pressure did not play any influential role in the process, at least concerning the analyzed experimental domain on this industrial plant. A model for computing the extraction yield as a function of temperature and pressure was obtained. This study shows that it is possible to obtain good quality RBO, rich in γ-oryzanol and essential fatty acids, using low temperatures and pressures, starting from a rice milling by-product. Graphical Abstract: [Figure not available: see fulltext.

    The Charge Form Factor of the Neutron at Low Momentum Transfer from the 2H⃗(e⃗,e′n)p^{2}\vec{\rm H}(\vec{\rm e},{\rm e}'{\rm n}){\rm p} Reaction

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    We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio GEn/GMnG^{n}_{E}/G^{n}_{M} was extracted from the beam-target vector asymmetry AedVA_{ed}^{V} at four-momentum transfers Q2=0.14Q^{2}=0.14, 0.20, 0.29 and 0.42 (GeV/c)2^{2}.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let

    Measurement of the proton electric to magnetic form factor ratio from \vec ^1H(\vec e, e'p)

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    We report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared Q2Q^2 from 0.15 to 0.65 (GeV/c)2^2. Significantly improved results on the proton electric and magnetic form factors are obtained in combination with previous cross-section data on elastic electron-proton scattering in the same Q2Q^2 region.Comment: 4 pages, 2 figures, submitted to PR

    Measurements of the Generalized Electric and Magnetic Polarizabilities of the Proton at Low Q2 Using the VCS Reaction

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    The mean square polarizability radii of the proton have been measured for the first time in a virtual Compton scattering experiment performed at the MIT-Bates out-of-plane scattering facility. Response functions and polarizabilities obtained from a dispersion analysis of the data at Q2=0.06 GeV2/c2 are in agreement with O(p3) heavy baryon chiral perturbation theory. The data support the dominance of mesonic effects in the polarizabilities, and the increase of beta with increasing Q2 is evidence for the cancellation of long-range diamagnetism by short-range paramagnetism from the pion cloud

    Investigation of the conjectured nucleon deformation at low momentum transfer

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    We report new precise H(e,e′p)π0(e,e^\prime p)\pi^0 measurements at the Δ(1232)\Delta(1232) resonance at Q2=0.127Q^2= 0.127 (GeV/c)2^2 using the MIT/Bates out-of-plane scattering (OOPS) facility. The data reported here are particularly sensitive to the transverse electric amplitude (E2E2) of the γ∗N→Δ\gamma^* N\to\Delta transition. Analyzed together with previous data yield precise quadrupole to dipole amplitude ratios EMR=(−2.3±0.3stat+sys±0.6model)EMR = (-2.3 \pm 0.3_{stat+sys} \pm 0.6_{model})% and CMR=(−6.1±0.2stat+sys±0.5model)CMR = (-6.1 \pm 0.2_{stat+sys}\pm 0.5_{model})% and for M1+3/2=(41.4±0.3stat+sys±0.4model)(10−3/mπ+)M^{3/2}_{1+} = (41.4 \pm 0.3_{stat+sys}\pm 0.4_{model})(10^{-3}/m_{\pi^+}). They give credence to the conjecture of deformation in hadronic systems favoring, at low Q2Q^2, the dominance of mesonic effects.Comment: 4 pages, 1figur

    Measurement of the Partial Cross Sections s(TT), s(LT) and [s(T)+epsilon*s(L)] of the p(e,e' pi+)n Reaction in the Delta(1232) Resonance

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    We report new precision p(e,e' pi+})n measurements in the Delta(1232) resonance at Q2 = 0.127(GeV/c)2 obtained at the MIT-Bates Out-Of-Plane scattering facility. These are the lowest, but non-zero, Q2 measurements in the pi+ channel. The data offer new tests of the theoretical calculations, particularly of the background amplitude contributions. The chiral effective field theory and Sato-Lee model calculations are not in agreement with this experiment
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