292 research outputs found
Constraining dark energy models using the lookback time to galaxy clusters and the age of the universe
An impressive amount of different astrophysical data converges towards the
picture of a spatially flat universe undergoing a today phase of accelerated
expansion. The nature of the dark energy dominating the energy content of the
universe is still unknown and a lot of different scenarios are viable
candidates to explain cosmic acceleration. Most of the methods employed to test
these cosmological models are essentially based on distance measurements to a
particular class of objects. A different method, based on the lookback time to
galaxy clusters and the age of the universe, is used here. In particular, we
constrain the characterizing parameters of three classes of dark energy
cosmological models to see whether they are in agreement with this kind of
data, based on time measurements rather than distance observations.Comment: 13 pages, 8 figures, accepted for publication on Physical Review
Status of Salerno Laboratory (Measurements in Nuclear Emulsion)
A report on the analysis work in the Salerno Emulsion Laboratory is
presented. It is related to the search for nu_mu->nu_tau oscillations in CHORUS
experiment, the calibrations in the WANF (West Area Neutrino Facility) at Cern
and tests and preparation for new experiments.Comment: Proc. The First International Workshop of Nuclear Emulsion Techniques
(12-24 June 1998, Nagoya, Japan), 15 pages, 11 figure
Rotating Electromagnetic Waves in Toroid-Shaped Regions
Electromagnetic waves, solving the full set of Maxwell equations in vacuum,
are numerically computed. These waves occupy a fixed bounded region of the
three dimensional space, topologically equivalent to a toroid. Thus, their
fluid dynamics analogs are vortex rings. An analysis of the shape of the
sections of the rings, depending on the angular speed of rotation and the major
diameter, is carried out. Successively, spherical electromagnetic vortex rings
of Hill's type are taken into consideration. For some interesting peculiar
configurations, explicit numerical solutions are exhibited.Comment: 27 pages, 40 figure
Comparison of meat quality characteristics and oxidative stability between conventional and free-range chickens
The aim of this research was to evaluate quality traits and oxidative stability of meat products from free range (FR) and conventionally (C) raised chickens as they actually reach consumers in the Italian retail market. FR female and male chickens (n=1500 + 1500), medium growing Isa strain, were raised under commercial conditions for 56 (1.8 kg of live wt.) and 70 d (3.1 kg of live wt.), respectively; C female and male birds (n=5000 + 5000) were a fast growing hybrid (Ross 708) and were separately raised for 39 (1.9 kg of live wt.) and 50 d (3.1 kg of live wt.), respectively. A total of 96 chickens (equally divided by production system and sex) were slaughtered into 2 separate sessions, to obtain the main two commercial categories (rotisserie and cut-up, respectively). After slaughtering, 12 carcasses of each treatment group were randomly selected and used to assess quality properties, chemical composition and oxidation stability of breast and leg meat. C birds had dramatic higher carcass and breast meat yield, whereas FR had higher wing and leg yields. FR birds exhibited higher water holding capacity in both breast and leg meat. Although shear force did not differ in breast meat, legs from FR birds were tougher. Fatty acid composition of FR breast and thigh meat of both categories were characterized by a higher PUFA n-6-/n-3 ratio. In general, a low lipid oxidation level (peroxide value (PV) < 1.3 meq O2/kg of lipid and thiobarbituric acid reactive substances (TBARs) < 0.2 mg MDA/kg of sample) was found in breast and legs, regardless of the commercial category. However, the C system significantly increased PV in rotisserie thigh meat, whereas FR led to a significantly higher TBARs in breast meat. Our results demonstrated that free range can modify the properties of chicken meat and also highlighted the importance of the animal genetic background to select nutritional strategies to improve meat quality traits and oxidative stability in poultry
Effect of dietary thymol supplementation on lipid oxidation of chicken legs as related to storage conditions
The aim of this research was to evaluate the effect of dietary thymol supplementation on lipid oxidation of chicken leg meat during refrigerated shelf-life. Chickens belonging to Ross 308 hybrid were raised under experimental conditions up to 3 kg of live weight, using three dietary treatments: control (without supplementation, C), treatment 1 (C+0.1% w/w thymol supplementation, T1) and treatment 2 (C+0.2% w/w thymol supplementation, T2). After slaughtering, the chicken legs with skin were stored under conventional (CON) and modified atmosphere (MAP) at temperature of 2-4°C for 14 days. Lipid oxidation was monitored by the determination of primary (peroxide value, PV) and secondary (thiobarbituric acid reactive substances, TBARs) products at 3, 7, 10 and 14 days of storage under both CON and MAP conditions and compared with values found on fresh meat. The three different dietary treatments did not significantly affect the lipid oxidation parameters. PV ranged between 0.5-13.0, 0.7-13.0 and 1.0-11.0 meq O2/kg of lipid in poultry meat obtained with C, T1 and T2 diets, respectively. TBARs varied between 0.1-0.7, 0.1- 0.6 and 0.2-0.5 mg MDA/kg of meat in poultry meat obtained with C, T1 and T2 diets, respectively. On the other hand, interaction effect of diets and storage conditions were significant (P≤0.05) in PV formation, as it was delayed under MAP (maximum PV level after 2 and 5 days of storage in C and thymol-containing diets, respectively) with respect to conventional storage (PV apex after 2 days of storage). However, not significant differences (P≥0.05) were found on TBARs level as related to storage conditions. In conclusion, this study demonstrated that dietary thymol supplementation coupled to MAP storage conditions delay lipid oxidation of chicken legs with skin, thus improving their shelf-life
CD157 signaling promotes survival of acute myeloid leukemia cells and modulates sensitivity to cytarabine through regulation of anti-apoptotic Mcl-1.
CD157/BST-1 (a member of the ADP-ribosyl cyclase family) is expressed at variable levels in 97% of patients with acute myeloid leukemia (AML), and is currently under investigation as a target for antibody-based immunotherapy. We used peripheral blood and bone marrow samples from patients with AML to analyse the impact of CD157-directed antibodies in AML survival and in response to cytarabine (AraC) ex vivo. The study was extended to the U937, THP1 and OCI-AML3 AML cell lines of which we engineered CD157-low versions by shRNA knockdown. CD157-targeting antibodies enhanced survival, decreased apoptosis and reduced AraC toxicity in AML blasts and cell lines. CD157 signaling activated the PI3K/AKT/mTOR and MAPK/ERK pathways and increased expression of Mcl-1 and Bcl-XL anti-apoptotic proteins, while decreasing expression of Bax pro-apoptotic protein, thus preventing Caspase-3 activation. The primary CD157-mediated anti-apoptotic mechanism was Bak sequestration by Mcl-1. Indeed, the Mcl-1-specific inhibitor S63845 restored apoptosis by disrupting the interaction of Mcl-1 with Bim and Bak and significantly increased AraC toxicity in CD157-high but not in CD157-low AML cells. This study provides a new role for CD157 in AML cell survival, and indicates a potential role of CD157 as a predictive marker of response to therapies exploiting Mcl-1 pharmacological inhibition
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