Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

The Wide-field Spectroscopic Telescope (WST) Science White Paper

The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat

Cytotoxicity and genotoxicity of salicylate‐ and calcium silicate‐based root canal sealers on primer human periodontal ligament fibroblasts

Abstract The aim of this study was to evaluate the biocompatibility of epoxy-resin-based AHPlus, salicylate-based MTA-Fillapex and calcium silicate-based iRootSP root canal sealers. Cytotoxicity was assessed by XTT test. The extracts from sealers of different setting times were serially diluted. Cell viability was calculated as the percentage of the control group (100%). The optimal concentration of each sealer was used at genotoxicity test, and micronuclei formations were detected. Statistical analyses were done by using Kruskal–Wallis and Dunn post hoc test with Bonferroni correction. AHPlus and MTA-Fillapex showed the lowest percentage of cell viability at higher concentrations (1:1, 1:2, 1:4), especially at first 12 h. iRootSP showed higher viability at all concentrations and times than AHPlus and MTA-Fillapex. At genotoxicity assay, AHPlus increased the number of micronuclei. MTA-Fillapex slightly induced micronucleus formation (not significant) and iRootSP was not increased. In conclusion, calcium silicate-based iRootSP had lowest cytotoxic and genotoxic potential and can be considered as a highly biocompatible material.Selcuk University, Scientific Research Projects Coordination Unit (SUBAP No:12202014)

Anchored fibrous chrysotile silica and its ability in using nitrogen basic centers on cation complexing from aqueous solution

Amorphous silica gel obtained through natural chrysotile was lixiviated with hydrochloric acid, which was chemically modified with organosilanes (H3CO)(3)SiR, where R corresponds to the organic moieties -CH2CH2CH2NH2 and -CH2CH2CH2NHCH2CH2NH2, yielding solids named SIL1 and SIL2. These anchored silicas showed 2.14 +/- 0.05 and 1.90 +/- 0.04 mmol g(-1) of attached amino groups on surfaces SIL1 and SIL2, respectively. The isotherms of adsorption data were obtained by batchwise process, whose values were adjusted to a modified Langmuir equation. The maximum adsorption capacity showed the sequence for copper and cobalt as 1.02, 0.35 mmol g(-1) on SIL2 and 0.71, 0.26 mmol g(-1) on SIL1, respectively. By using calorimetric titration, the enthalpy change of the adsorption process was 18.77 +/- 0.75 and -43.29 +/- 1.08 kJ mol(-1) for copper, 12.70 +/- 0.57 and -169.3 +/- 1.23 kJ mol(-1) for cobalt on SIL1 and SIL2, respectively. Negative Gibbs free energy values are in agreement with the spontaneity of the proposed reactions involving both divalent cations, when complexed by basic amino groups attached to pendant chain covalently bonded to the inorganic surface. (C) 2003 Elsevier B.V. All rights reserved.22741699859