742 research outputs found

    Methyl carbamates of phosphatidylethanolamines and phosphatidylserines reveal bacterial contamination in mitochondrial lipid extracts of mouse embryonic fibroblasts

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    Abstract The occurrence of methyl carbamates of phosphatidylethanolamines and phosphatidylserines in the lipid extract of mitochondria obtained from mouse embryonic fibroblasts was ascertained by hydrophilic interaction liquid chromatography with electrospray ionization single and multi-stage mass spectrometry, performed using sinergically a high resolution (quadrupole-Orbitrap) and a low resolution (linear ion trap) spectrometer. Two possible routes to the synthesis of methyl carbamates of phospholipids were postulated and evaluated: (i) a chemical transformation involving phosgene, occurring as a photooxidation by-product in the chloroform used for lipid extraction, and methanol, also used for the latter; (ii) an enzymatic methoxycarbonylation reaction due to an accidental bacterial contamination, that was unveiled subsequently on the murine mitochondrial sample. A specific lipid extraction performed on a couple of standard phosphatidyl-ethanolamines/-serines, based on purposely photo-oxidized chloroform and deuterated methanol, indicated route (i) as negligible in the specific case, thus highlighting the enzymatic route related to bacterial contamination as the most likely source of methyl carbamates. The unambiguous recognition of the latter might represent the starting point toward a better understanding of their generation in biological systems and a minimization of their occurrence when an artefactual formation is ascertained

    Corrigendum: “Measurement of ⁷³Ge(n,Îł) cross sections and implications for stellar nucleosynthesis” [Phys. Lett. B 790 (2019) 458–465]

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    Beam merging assisted by a bent crystal

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    Bunch merging is a well-established technique to increase the intensity of synchrotrons and the luminosity of circular colliders. We suggest to exploit a combination of channeling, volume reflection and amorphous interactions in a bent crystal for beam merging in a transfer line. Two beams converging into the bent crystal along special directions should emerge in almost parallel directions. A merging scenario is discussed, and data collected by the UA9 Collaboration are reprocessed to prove its feasibility. Comparison with magnetic stacking, which is a similar process, is presented

    Towards a muon collider

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    TF07 Snowmass Report: Theory of Collider Phenomena

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    11+11 pages, 343 contributors, 1 key formula; contribution to Snowmass 2021, draft report of the Theory Frontier topical group for Collider Phenomenology (TF07), comments and suggestions welcome ; v2: updated contributor listTheoretical research has long played an essential role in interpreting data from high-energy particle colliders and motivating new accelerators to advance the energy and precision frontiers. Collider phenomenology is an essential interface between theoretical models and experimental observations, since theoretical studies inspire experimental analyses while experimental results sharpen theoretical ideas. This report -- from the Snowmass 2021 Theory Frontier topical group for Collider Phenomenology (TF07) -- showcases the dynamism, engagement, and motivations of collider phenomenologists by exposing selected exciting new directions and establishing key connections between cutting-edge theoretical advances and current and future experimental opportunities. By investing in collider phenomenology, the high-energy physics community can help ensure that theoretical advances are translated into concrete tools that enable and enhance current and future experiments, and in turn, experimental results feed into a more complete theoretical understanding and motivate new questions and explorations

    Towards a muon collider

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    The role of antiplatelet therapies on incidence and mortality of hepatocellular carcinoma

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    Aim: To evaluate the impact of antiplatelet therapy (APT)on the incidence of hepatocellular carcinoma (HCC) and mortality following its treatment. Methods: A systematic literature search was performed using PubMed and Cochrane Central Register of Controlled Trials Databases. Two HCC clinical settings were explored: (i) incidence, and (ii) death after any HCC treatment. Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated to compare the pooled data between patients who received or did not receive APT. Results: A total of 20 studies were identified, of whom 15 focused on HCC incidence, including 2,685,009 patients, and five on post-treatment death, including 3281 patients. APT was associated with an overall reduced risk of HCC incidence (OR: 0.63; 95%CI = 0.51-0.79; p < 0.001) as well as of post-treatment mortality (OR: 0.54; 95%CI = 0.35-0.83; p = 0.006). Conclusions: Current data suggest that APT correlated with higher HCC incidence and poor overall survival following tumour treatment

    Neutron-induced fission cross sections of <math><mmultiscripts><mi>Th</mi><mprescripts/><none/><mn>232</mn></mmultiscripts></math> and <math><mmultiscripts><mi mathvariant="normal">U</mi><mprescripts/><none/><mn>233</mn></mmultiscripts></math> up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility

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    International audienceThe neutron-induced fission cross sections of Th232 and U233 were measured relative to U235 in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of Th232, and from 0.7 eV in case of U233), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of U233, previous results available in EXFOR, whereas in the case of Th232 these data were obtained from our measurement, using PPACs and targets tilted 45∘ with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those (p,f) data with our (n,f) data on Th232 and U233 and on other isotopes studied earlier at n_TOF using the same experimental setup

    Neutron-induced fission cross sections of Th 232 and U 233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility

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    The neutron-induced fission cross sections of 232^{232}Th and 233^{233}U were measured relative to 235^{235}U in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of 232^{232}Th, and from 0.7 eV in case of 233^{233}U), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of 233^{233}U, previous results available in EXFOR, whereas in the case of 232^{232}Th these data were obtained from our measurement, using PPACs and targets tilted 45∘ with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those (p,f) data with our (n,f) data on 232^{232}Th and 233^{233}U and on other isotopes studied earlier at n_TOF using the same experimental setup

    Predictors of serious adverse events and non-response in cirrhotic patients with primary biliary cholangitis treated with obeticholic acid

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    Background &amp; Aims: Obeticholic acid (OCA) has recently been restricted in patients with primary biliary cholangitis (PBC) with “advanced cirrhosis” because of its narrow therapeutic index. We aimed to better define the predicting factors of hepatic serious adverse events (SAEs) and non-response in cirrhotic patients undergoing OCA therapy. Methods: Safety and efficacy of treatment were evaluated in a cohort of consecutive PBC cirrhotic patients started with OCA. OCA response was evaluated according to the Poise criteria. Risk factors for hepatic SAEs and non-response were reported as risk ratios (RR) with 95% confidence intervals (CIs). Results: One hundred PBC cirrhotics were included, 97 Child-Pugh class A and 3 class B. Thirty-one had oesophageal varices and 5 had a history of ascites. Thirty-three per cent and 32% of patients achieved a biochemical response at 6 and 12 months respectively. Male sex (adjusted-RR 1.75, 95%CI 1.42–2.12), INR (1.37, 1.00–1.87), Child-Pugh score (1.79, 1.28–2.50), MELD (1.17, 1.04–1.30) and bilirubin (1.83, 1.11–3.01) were independently associated with non-response to OCA. Twenty-two patients discontinued OCA within 12 months: 10 for pruritus, 9 for hepatic SAEs (5 for jaundice and/or ascitic decompensation; 4 for upper digestive bleeding). INR (adjusted-RR 1.91, 95%CI 1.10–3.36), lower albumin levels (0.18, 0.06–0.51), Child-Pugh score (2.43, 1.50–4.04), history of ascites (3.5, 1.85–6.5) and bilirubin (1.30, 1.05–1.56), were associated with hepatic SAEs. A total bilirubin≄1.4&nbsp;mg/dl at baseline was the most accurate biochemical predictor of hepatic SAEs under OCA. Conclusions: An accurate baseline assessment is crucial to select cirrhotic patients who can benefit from OCA. Although OCA is effective in one third of cirrhotics, bilirubin level ≄1.4&nbsp;mg/dl should discourage from its use
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