119 research outputs found

    Transverse polarization measurement of Λ hyperons in pNe collisions at √sNN = 68.4 GeV with the LHCb detector

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    A measurement of the transverse polarization of the Λ andΛ hyperons in pNe fixed-target collisions at √ sNN = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay Λ → pπ− together with its charge conjugated process, the integrated values measured are PΛ = 0.029 ± 0.019 (stat) ± 0.012 (syst), PΛ = 0.003 ± 0.023 (stat) ± 0.014 (syst). Furthermore, the results are shown as a function of the Feynman x variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements

    Study of b-hadron decays to Λc^+h-h' final states

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    Decays of Ξ − b and Ω − b baryons to Λ + c h −h ′− final states, with h −h ′− being π −π −, K−π\ud − and K−K− meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7 fb−1 of pp collisions collected at centre-of-mass energies √ s = 7, 8 and 13 TeV. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the B− → Λ + c pπ− mode, are measured, with Ξ − b → Λ + c K−π −, Ξ − b → Λ + c K−K− and Ω − b → Λ + c K−K− decays being observed at over 5 σ significance. The Ξ − b → Λ + c K−π − mode is also used to measure the Ξ − b production asymmetry, which is found to be consistent with zero. In addition, the B− → Λ + c pK− decay is observed for the first time, and its branching fraction is measured relative to that of the B− → Λ + c pπ− mode

    Precision measurement of the Ξb− baryon lifetime

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    A sample of pp collision data, corresponding to an integrated luminosity of 5.5 fb−1 and collected by the LHCb experiment during LHC Run 2, is used to measure the ratio of the lifetime of the Ξ− b baryon to that of the Λ0 b baryon, rτ ≡ τΞ− b =τΛ0 b . The value rτ = 1.076 0.013 0.006 is obtained, where the first uncertainty is statistical and the second systematic. This value is averaged with the corresponding value from Run 1 to obtain rRun 1;2 τ = 1.078 0.012 0.007. Multiplying by the world-average value of the Λ0 b lifetime yields τ Run 1;2 Ξ− b = 1.578 0.018 0.010 0.011 ps, where the uncertainties are statistical, systematic, and due to the limited knowledge of the Λ0 b lifetime. This measurement improves the precision of the current world average of the Ξ− b lifetime by about a factor of 2, and is in good agreement with the most recent theoretical predictions

    Observation of muonic Dalitz decays of chib mesons and precise spectroscopy of hidden-beauty states

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    The decays of the χb1(1P), χb2(1P), χb1(2P) and χb2(2P) mesons into the Υ(1S)µ +µ − final state are observed with a high significance using proton-proton collision data collected with the LHCb detector and corresponding to an integrated luminosity of 9 fb−1 . The newly observed decays together with the Υ(2S) → Υ(1S)π +π − and Υ(3S) → Υ(2S)π +π − decay modes are used for precision measurements of the mass and mass splittings for the hidden-beauty states

    1. In hypertensive women, both the results of the screening for hyperaldosteronism and of the evaluation of insulin resistance depend on the timing of assessment in relation to the ovarian cycle

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    We have reported that in low-renin hypertensive women the increment of plasma aldosterone that occurs in the luteal compared to the follicular phase of the ovarian cycle markedly increases the positivity for suspected primary hyperaldosteronism; it has also been reported that aldosteronism is associated with insulin resistance (IR) (Garg J.Clin.Endocrinol.Metab, 2010) and that IR slightly but significantly increases in the luteal phase in normotensive women (Yeung J.Clin.Endocrinol.Metab, 2010). We here report the results of a study on 31 women in the fertile age evaluated because of arterial hypertension in whom both aldosterone and HOMA-IR index (glucose*insulin/405) levels were investigated during the ovarian cycle. All measures (plasma aldosterone, PRA, insulin, glucose and progesterone levels) were done at the 5-7th (follicular phase) and 21-25th (luteal phase) day of the menstrual cycle, without hypotensive therapy or with doxazosin 4mg per day. All women reported a regular cycle, age: 41.7±8.4 [mean±SD] (range:19-53) years, BMI 25.1±4.6 (19.3-35.8) kg/m2. Compared to the follicular phase, in the luteal phase plasma progesterone (P), aldosterone (ALDO), renin activity (PRA), insulin (I) and HOMA-IR all increased significantly: P from 0.6±0.3 to 8.7±4.1 ng/mL (p15 ng/dL with ALDO/PRA>40 increased from 7/31 (23%) to 16/31 (52%); the proportion of HOMA-IR>2.5 increased from 3/22 (14%) to 6/22 (27%). Multiple regression analysis demonstrated that P - but not ALDO - and BMI were strong positive independent predictors of plasma insulin and HOMA-IR: univariate analysis 1.) I vs P p=0.016; vs BMI p<0.0001; 2.) HOMA-IR vs P p=0.065; vs BMI p<0.0001; multivariate analysis 1.) I vs P (p=<0.002) + BMI (p<0.0001); 2.) HOMA-IR vs P (p<0.02) + BMI (p<0.0001). These results in hypertensive women confirm that plasma aldosterone may greatly increase during the luteal phase of the ovarian cycle and suggest that also insulin resistance may increase to a greater extent than in normotensive women. The ovarian cycle is thus a source of variability of plasma aldosterone and of insulin resistance in hypertensive women in fertile age, with potential relevance in the diagnostic workup and pathophysiology of hypertension

    Antioxidants in the Diet and Cognitive Function: Which Role for the Mediterranean Life-style?

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    This review aims to focus on main antioxidants- abundantly contained in the diet- as well as of the whole Mediterranean diet and life-style and their relationship with cognitive function, especially critical in two phases of life, in children until adolescence and oldness. The role of emerging biochemical and molecular biomarkers as opportunity to estimate more accurately nutritional assumption and requirement, in terms of cognitive preservation and disease risk, will be also discussed. The cluster of factors within the Mediterranean pattern -which include not only nutritional, but also physical, social, and stimulating aspects- is still largely understudied as a whole, but it is proposed as attractive research area and tool for public health planning of prevention and intervention

    Modified in vitro release of the chronobiotic hormone melatonin from matrix tablets based on the marine sulfated polysaccharide ulvan

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    In the last decades the paradigm of including excipients in the formulations as inert substances, aiding production processes, has changed and they are now approached as multifunctional compounds. This means that several functions apply, spreading from the stabilization and modified release, to providing biocompatible properties and targeting moieties. In the present work, the algal sulfated polysaccharide ulvan, which remains a rather unexploited biomaterial for applications in the design of drug delivery systems, was used as a formulant in hydrophilic matrix systems, containing the chronobiotic hormone melatonin (MLT). The MLT&apos;s in vitro modified release profile in gastrointestinal-like fluids was probed. In general, the % release profile of MLT from ulvan-based tablets, was found to be relatively higher than that of the market drug Circadin® at pH 1.2 (2 h), with the exception of the formulations containing HPMC K15M. The release of most of the ulvan-based formulations follow a sigmoidal pattern (Super Case II mechanism, n &amp;gt; 0.89), which denotes that the drug release is controlled by polymer relaxation and/or erosion. © 201

    Early impairment of beta-cell function and insulin sensitivity characterizes normotolerant Caucasian women with previous gestational diabetes.

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    BACKGROUND AND AIMS: Women with previous gestational diabetes (pGDM) are at high risk of developing type 2 diabetes mellitus. The aim of this study was to evaluate insulin action and insulin secretion in women with pGDM. METHODS AND RESULTS: One hundred and fifty-three pGDM women and 45 with normal glucose tolerance during pregnancy (controls) were studied 1-3years after delivery. Insulin sensitivity (ISI) and beta-cell secretory capacity (beta-index) were derived from 75-g OGTT. Disposition Index was calculated as the product of beta-index and ISI. One hundred and twenty-two pGDM were normotolerant (NGT) and 31 had impaired glucose regulation (IGR) i.e. impaired glucose tolerance and/or impaired fasting glucose. NGT-pGDM, as compared to controls, had significant impairment in insulin action (ISI: 5.46+/-2.81 vs. 7.38+/-3.68, P<0.01) and insulin secretion (beta-index: 4.68+/-1.01 vs. 5.24+/-0.82 pmol/min/m(2); P<0.01). A further impairment was apparent in IGR-pGDM for beta-index (4.16+/-1.09; P<0.05). The disposition index was reduced in NGT-pGDM as compared to controls (33.9%) and further reduced in IGR-pGDM (28.6%, vs. NGT-pGDM; ANOVA P<0.001). In women of normal weight, ISI and beta-index were significantly (P<0.01) impaired in NGT-pGDM compared to controls and further reduced in IGR-pGDM, although a more pronounced defect in insulin secretion was apparent in these women (beta-index: 4.02+/-0.9; P<0.05). CONCLUSIONS: Normotolerant women with pGDM show both impairment in insulin secretion and action irrespective of body weight. A more pronounced defect in insulin secretion seems to characterize normal weight women while a more prominent defect in insulin action is found in overweight women
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