Measuring the free fall of antihydrogen

After the first production of cold antihydrogen by the ATHENA and ATRAP experiments ten years ago, new second-generation experiments are aimed at measuring the fundamental properties of this anti-atom. The goal of AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is to test the weak equivalence principle by studying the gravitational interaction between matter and antimatter with a pulsed, cold antihydrogen beam. The experiment is currently being assembled at CERN's Antiproton Decelerator. In AEGIS, antihydrogen will be produced by charge exchange of cold antiprotons with positronium excited to a high Rydberg state (n > 20). An antihydrogen beam will be produced by controlled acceleration in an electric-field gradient (Stark acceleration). The deflection of the horizontal beam due to its free fall in the gravitational field of the earth will be measured with a moire deflectometer. Initially, the gravitational acceleration will be determined to a precision of 1%, requiring the detection of about 105 antihydrogen atoms. In this paper, after a general description, the present status of the experiment will be reviewed

Improved astrophysical rate for the 18O(p,α)15N reaction by underground measurements

The 18O(p,\u3b1)15N reaction affects the synthesis of 15N, 18O and 19F isotopes, whose abundances can be used to probe the nucleosynthesis and mixing processes occurring deep inside asymptotic giant branch (AGB) stars. We performed a low-background direct measurement of the 18O(p,\u3b1)15N reaction cross-section at the Laboratory for Underground Nuclear Astrophysics (LUNA) from center of mass energy Ec.m.=340keV down to Ec.m.=55keV, the lowest energy measured to date corresponding to a cross-section of less than 1 picobarn/sr. The strength of a key resonance at center of mass energy Er=90keV was found to be a factor of 10 higher than previously reported. A multi-channel R-matrix analysis of our and other data available in the literature was performed. Over a wide temperature range, T=0.01\u20131.00GK, our new astrophysical rate is both more accurate and precise than recent evaluations. Stronger constraints can now be placed on the physical processes controlling nucleosynthesis in AGB stars with interesting consequences on the abundance of 18O in these stars and in stardust grains, specifically on the production sites of oxygen-rich Group II grains

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

Exploring the WEP with a pulsed cold beam of antihydrogen

The AEGIS experiment, currently being set up at the Antiproton Decelerator at CERN, has the objective of studying the free fall of antimatter in the Earth's gravitational field by means of a pulsed cold atomic beam of antihydrogen atoms. Both duration of free fall and vertical displacement of the horizontally emitted atoms will be measured, allowing a first test of the WEP with antimatter

Relative contact density and <i>o</i>-Ps lifetime as measured in some molecular solids and polymers (symbols are explained in <b>Table 1</b>).

<p>Relative contact density and <i>o</i>-Ps lifetime as measured in some molecular solids and polymers (symbols are explained in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109937#pone-0109937-t001" target="_blank"><b>Table 1</b></a>).</p

Dependence of the number <i>n</i> on the radius <i>r</i>₀ of the cavity trapping Ps.

<p>Dependence of the number <i>n</i> on the radius <i>r</i>₀ of the cavity trapping Ps.</p

Relative contact density <i>η</i> and <i>o</i>-Ps lifetime <i>τ</i> in some molecular solids and polymers.

a<p>Polytetrafluoroethylene.</p>b<p>Atactic polypropylene.</p>c<p>Polyethylene.</p>d<p>Poly(methyl methacrylate).</p>e<p>2(4-tert-Butylphenyl)-5-(4-byphenylyl)1,3,4-oxadiazol.</p>f<p>2,5-Diphenyl-1,3,4-oxadiazol.</p>g<p>2,5-Diphenyl-oxazol.</p><p>Relative contact density <i>η</i> and <i>o</i>-Ps lifetime <i>τ</i> in some molecular solids and polymers.</p

Pemetrexed-induced acute kidney failure following irreversible renal damage: two case reports and literature review

Background: Pemetrexed (PEM) is a new-generation multitargeted antifolate agent with a demonstrated broad-spectrum activity in several types of human cancers, including non-small cell lung cancer (NSCLC) and mesothelioma. Major side effects include dose-limiting hematologic toxicities. PEM nephrotoxicity is well known; however, its frequency is considered to be low. Case Presentation: Here we report two cases of acute kidney injury (AKI) related to PEM administration (500 mg/m2) in patients with NSCLC. The first patient required hemodialysis treatment and was submitted to renal biopsy which showed acute tubular damage and interstitial edema without acute tubular necrosis. No other potential nephrotoxic agents were identified. The second patient developed AKI, not proven by biopsy and did not require renal replacement therapy. Both patients, on regular supplementation with folic acid and vitamin B12, concomitantly developed myelosuppression and even several months after PEM withdrawal, showed only a modest improvement of renal function. Conclusions: PEM is an antifolate antineoplastic agent with a broad-spectrum activity in locally advanced or metastatic NSCLC. It has been shown that PEM allows longer survival. The risk of acute or chronic kidney disease may be one of the prices to be paid for this success

Clinical usefulness of autoantibodies to M-type phospholipase A2 receptor (PLA2R) for monitoring disease activity in idiopathic membranous nephropathy (IMN)

Autoantibodies to M-type phospholipase A2 receptor (PLA2R) are specific markers of idiopathic membranous nephropathy (IMN). They can differentiate IMN from other glomerular diseases and primary from secondary forms of MN. Preliminary data suggest that anti-PLA2R antibody titer correlates with disease activity but more solid evidence is needed.To evaluate the performance of anti-PLA2R antibody for monitoring nephropathy activity, 149 anti-PLA2R antibody measurements were performed during the follow-up of 42 biopsy proven IMN consecutive patients. Patients were enrolled either at time of diagnosis (33 cases, inception cohort) or after diagnosis (9 patients, non-inception cohort).Anti-PLA2R detection was performed using the highly sensitive transfected cell-based indirect immunofluorescence (IIFT).Over the follow-up there was a linear time-trend of decreasing proteinuria (P < 0.001), increasing serum albumin (P < 0.001) and decreasing PLA2R antibody levels (P = 0.002). There was a statistically significant association between changes in PLA2R antibody levels and the clinical course of PLA2R-positive IMN. The positive PLA2R serum antibody status was linearly associated with increasing proteinuria and decreasing serum albumin over time, compared with negative antibody status. Moreover, the strong correlation between the clinical conditions and PLA2R antibody levels allowed the prediction of prevalence distribution of patients with active disease, partial and complete remission. Over the course of the follow-up, the probability of halving proteinuria increased 6.5 times after disappearance of PLA2R antibodies.Our data suggest that the serial evaluation of anti-PLA2R antibodies could help in optimal timing and duration of the immunosuppressive therapy, reducing over(under)-treatment and associated side-effects