171,202 research outputs found
Status and perspectives of the neutron time-of-flight facility n TOF at CERN
No full textThe neutron time-of-flight facility of CERN, called n_TOF, started its operation in 2001, and since then it plays a major role in the field of neutron cross-section measurements. The two beam-lines available provide an excellent combination of good energy resolution and high instantaneous neutron flux, combining the time-of-flight method with a powerful neutron spallation source. So far, a large number of experiments has been performed on a variety of isotopes of interest for nuclear astrophysics, advanced nuclear technologies, nuclear medicine, and for basic nuclear physics. After the CERN long shutdown, a new phase of data taking is planned to start in 2021. The R&D of a new spallation target is ongoing and its upgrade will bring important improvements in both beam lines, allowing the n_TOF Collaboration to perform new, challenging measurements
Galileo's Mathematization of Nature at the Crossroad between the Empiricist and the Kantian Tradition
No full textEmulsion templated scaffolds based on gelatin and glycosaminoglycans (Massimi: co-corresponding author)
No full textGelatin is one of the most commonly used biopolymer for creating cellular scaffolds due to its innocuous nature. To create stable gelatin scaffolds at physiological temperature (37 degrees C), chemical cross-linking is a necessary step. In a previous paper (Biomacromolecules 2006, 7, 3059-3068), cross-linking was carried out by either radical polymerization of the methacrylated derivative of gelatin (GMA) or through the formation of isopeptide bonds catalyzed by transglutaminase. The method of scaffold production was based on emulsion templating in which an organic phase is dispersed in the form of discrete droplets into a continuous aqueous solution of the biopolymer. Both kinds of scaffolds were tested as culture medium for hepatocytes. It turned out that the enzymatic cross-linked scaffold performed superiorily in this respect, even though it was mechanically less stable than the GMA scaffold. In the present paper, in an attempt to improve the biocompatibility of the GMA-based scaffold, biopolymers present in the extracellular matrix (ECM) were included in scaffold formulation, namely, chondroitin sulfate and hyaluronic acid. These biopolymers were derivatized with methacrylic moieties to undergo radical polymerization together with GMA. The morphology of the scaffolds was tuned to some extent by varying the volume fraction of the internal phase and to a larger extent by inducing a controlled destabilization of the precursor emulsion through the use of additives. In this way, scaffolds with 44% of the void volume attributable to voids with a diameter exceeding 60 microm and with 79% of the interconnect area attributable to interconnects with a diameter exceeding 20 microm in diameter could be successfully synthesized. To test whether the inclusion of ECM components into scaffold formulation resolves in an improvement of their biocompatibility with respect to GMA scaffolds, hepatocytes were seeded on both kinds of scaffolds and cell viability and function assays were carried out and compared
Programmazione per aree e tendenze occupazionali in una regione bifronte: l'Abruzzo tra Nord e Sud dell'Europa del 1992
No full text197 - Au(n, gamma) cross section in the resonance region
No full textThe (n, gamma) cross section of 197 - Au has been measured at n_TOF in the resolved resonance region, up to 5 keV, with the aim of improving the accuracy in an energy range where it is not yet considered standard. The measurements were performed with two different experimental setup and detection techniques, the total energy method based on C6D6 detectors, and the total absorption calorimetry based on a 4 BaF2 array. By comparing the data collected with the two techniques, two accurate sets of neutron-capture yields have been obtained, which could be the basis for a new evaluation leading to an extended cross-section standard. Overall good agreement is found between the n_TOF results and evaluated cross sections, with some significant exceptions for small resonances. A few resonances not included in the existing databases have also been observed
Retinoic acid modulates gap junctional intercellular communication in hepatocytes and hepatoma cells
No full textGap junctional communication permits the direct exchange of small molecules and ions and has been implicated in tissue homeostasis/metabolite exchange. The lack of gap junctional intercellular communication (GJIC) plays important roles in the promotion and progression of carcinogenesis. In the present study, we demonstrate that treatment of human hepatoma Hep G2 cells with retinoic acid (RA) results in increased amounts and phosphorylation of connexins, their stabilisation in plasma membrane plaques and enhanced GJIC. In cultured fetal hepatocytes, which represent a non-transformed, proliferating and incompletely differentiated liver system, the effects of RA are limited to the establishment of connexin in areas of cell-cell contact and the improvement of GJ1C. This suggests that modulation of cell-cell channel communication by RA occurs differently in these two experimental models: while RA is able to revert cell transformation in Hep G2 cells, in fetal hepatocytes it may induce the expression of a more differentiated phenotype
Characteristics and long-term outcome of infants with intracranial tumors diagnosed in the first year of life.
No full textn_TOF: Measurements of Key Reactions of Interest to AGB Stars
No full textIn the last 20 years, the neutron time-of-flight facility n_TOF at CERN has been providing relevant data for the astrophysical slow neutron capture process (s process). At n_TOF, neutron-induced radiative capture (n,γ) as well as (n,p) and (n,α) reaction cross sections are measured as a function of energy, using the time-of-flight method. Improved detection systems, innovative ideas and collaborations with other neutron facilities have lead to a considerable contribution of the n_TOF collaboration to studying the s process in asymptotic giant branch stars. Results have been reported for stable and radioactive samples, i.e.,24,25,26Mg,26Al,33S,54,57Fe,58,59,62,63Ni,70,72,73Ge,90,91,92,93,94,96Zr,139La,140Ce,147Pm,151Sm,154,155,157Gd,171Tm,186,187,188Os,197Au,203,204Tl,204,206,207Pb and209Bi isotopes, while others are being studied or planned to be studied in the near future. In this contribution, we present an overview of the most successful achievements, and an outlook of future challenging measurements, including ongoing detection system developments
Retinoic acid modulates gap junctional intercellular communication in hepatocytes and hepatoma cells
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