Free-electron lasers (FELs) are promising devices for generating light with laser-like properties in the extreme ultraviolet and X-ray spectral regions. Recently, FELs based on the self-amplified ...spontaneous emission (SASE) mechanism have allowed major breakthroughs in diffraction and spectroscopy applications, despite the relatively large shot-to-shot intensity and photon-energy fluctuations and the limited longitudinal coherence inherent in the SASE mechanism. Here, we report results on the initial performance of the FERMI seeded FEL, based on the high-gain harmonic generation configuration, in which an external laser is used to initiate the emission process. Emission from the FERMI FEL-1 source occurs in the form of pulses carrying energy of several tens of microjoules per pulse and tunable throughout the 65 to 20 nm wavelength range, with unprecedented shot-to-shot wavelength stability, low-intensity fluctuations, close to transform-limited bandwidth, transverse and longitudinal coherence and full control of polarization.
Complex I (NADH:ubiquinone oxidoreductase) is the first and largest multimeric complex of the mitochondrial respiratory chain. Human complex I comprises seven subunits encoded by mitochondrial DNA ...and 38 nuclear-encoded subunits that are assembled together in a process that is only partially understood. To date, mutations causing complex I deficiency have been described in all 14 core subunits, five supernumerary subunits, and four assembly factors. We describe complex I deficiency caused by mutation of the putative complex I assembly factor C20orf7. A candidate region for a lethal neonatal form of complex I deficiency was identified by homozygosity mapping of an Egyptian family with one affected child and two affected pregnancies predicted by enzyme-based prenatal diagnosis. The region was confirmed by microcell-mediated chromosome transfer, and 11 candidate genes encoding potential mitochondrial proteins were sequenced. A homozygous missense mutation in
C20orf7 segregated with disease in the family. We show that C20orf7 is peripherally associated with the matrix face of the mitochondrial inner membrane and that silencing its expression with RNAi decreases complex I activity.
C20orf7 patient fibroblasts showed an almost complete absence of complex I holoenzyme and were defective at an early stage of complex I assembly, but in a manner distinct from the assembly defects caused by mutations in the assembly factor NDUFAF1. Our results indicate that C20orf7 is crucial in the assembly of complex I and that mutations in
C20orf7 cause mitochondrial disease.
The mammography project at the SYRMEP beamline Dreossi, D; Abrami, A; Arfelli, F ...
European journal of radiology,
12/2008, Letnik:
68, Številka:
3
Journal Article, Conference Proceeding
Recenzirano
Abstract A clinical program for X-ray phase contrast (PhC) mammography with synchrotron radiation (SR) has been started in March 2006 at the SYRMEP beamline of Elettra, the SR facility in Trieste, ...Italy. The original beamline layout has been modified substantially and a clinical facility has been realized. In order to fulfill all security requirements, dedicated systems have been designed and implemented, following redundancy criteria and “fail safe” philosophy. Planar radiographic images are obtained by scanning simultaneously the patient and the detector through the stationary and laminar SR beam. In this first phase of the project a commercial screen-film system has been used as image receptor. Upon approval by the respective authorities, the mammography program is about half way to conclusion. Up to now about 50 patients have been examined. The patients are volunteers recruited by the radiologist after conventional examinations at the hospital resulted in an uncertain diagnosis. As an example one case of PhC SR mammography is shown and compared to conventional digital mammography. Preliminary analysis shows the high diagnostic quality of the PhC SR images that were acquired with equal or less delivered dose compared to the conventional ones.
A measurement of strange baryon and antibaryon production in Pb–Pb collisions has been carried out by the NA57 experiment at the CERN SPS, with 40 and 158 AGeV/c beam momentum. Results on Λ, Ξ and Ω ...hyperon yields at mid-rapidity in the most central 53% of Pb–Pb collisions at 40 AGeV/c are presented and compared with those obtained at higher energy, in the same collision centrality range.
The Λ and Ξ− yields per unit rapidity stay roughly constant while those of Ω−, Λ̄, Ξ̄+ and Ω̄+ increase when going to the higher SPS energy. Hyperon yields at the SPS are compared with those from the STAR experiment in sNN=130 GeV Au–Au collisions at RHIC.
The authors examine the radiation field produced in the vicinity of the main beam dump of the FERMI free-electron laser under the impact of a 1.4-GeV electron beam. Electromagnetic and neutron dose ...rates are calculated with the Fluka Monte Carlo code and compared with ionisation chamber and superheated drop detector measurements in various positions around the dump. Experimental data and simulation results are in good agreement with a maximum deviation of 25 % in a single location.
Together with the INFM and other Italian institutes, Sincrotrone Trieste has proposed and developed FERMI@ELETTRA in response to the Italian government's call for proposals from national institutes ...for a multipurpose pulsed laser X-ray source. The proposed FEL source will be located at the third-generation synchrotron radiation facility ELETTRA and will utilize the fully available 1.0-GeV normal conducting linac. The project is organized along three stages of development, allowing gradual improvements for the production of 40-, 10-, and 1.2-nm radiation. The first two phases involve upgrading the linac with a high-brightness photo-injector and bunch compressor for the generation of increasingly higher quality electron beams. The third phase requires both an increase in peak current and beam energy to 3.0GeV. The requirements of the user-community necessitate reproducible radiation sources with controllable polarization and wavelength. For this APPLE-type undulators will be implemented and seeding schemes will be used where possible. An overview of the proposal is presented elucidating linac upgrades and overall layout, electron beam simulations, and laser seed schemes.
AbstractThe NA57 experiment has measured strange baryon and antibaryon production in Pb-Pb collisions at 40 A GeV/c and 160 A GeV/c beam momenta. This presentation covers strangeness enhancement and ...transverse spectra from the 160 A GeV/c data, and energy dependence of the particle yields. Enhancement factors increase with increasing strangeness content of the particle, when production yields from Pb-Pb collisions are compared with those observed in p-Be and p-Pb interactions. The transverse mass spectra have been analysed both with exponential fits and using a transverse flow model.
The ALICE data acquisition system has been designed to support an aggregate event-building bandwidth of up to 2.5 GByte/s and a storage capability of up to 1.25 GByte/s to mass storage. A general ...framework called the ALICE Data Acquisition Test Environment (DATE) system has been developed as a basis for prototyping the components of the DAQ. DATE supports a wide spectrum of configurations from simple systems to more complex systems with multiple detectors and multiple event builders. Prototypes of several key components of the ALICE DAQ have been developed and integrated with the DATE system such as the ALICE Detector Data Link, the online data monitoring from ROOT and the interface to the mass storage systems. Combined tests of several of these components are being pursued during the ALICE Data Challenges. The architecture of the ALICE DAQ system will be presented together with the current status of the different prototypes. The recent addition of a Transition Radiation Detector (TRD) to ALICE has required a revision of the requirements and the architecture of the DAQ. This will allow for a higher level of data selection. These new opportunities and implementation challenges will also be presented.
The main purpose of the SYRMEP (SYnchrotron Radiation for MEdical Physics) research team is the investigation and development of innovative techniques for medical imaging. A dedicated beamline has ...been built at ELETTRA to evaluate the effectiveness of synchrotron-based techniques in medical radiology with particular interest to mammography, and more in general, to the imaging of biological and biomedical samples, either in planar or tomographic set-ups. Taking advantage of the high intensity and high spatial coherence of Synchrotron Radiation (SR), phase sensitive techniques such as Phase Contrast (PhC) and Diffraction Enhanced Imaging (DEI) can be applied. After successful studies carried out on test objects and in vitro samples, the research in mammography is aiming at in vivo clinical trials. For this purpose, the layout of the SYRMEP beamline has been substantially modified and the safety system has been completely redesigned to guarantee the compliance with current radiation protection guidelines. In the present paper, the main characteristics of the beamline and an overview of the results obtained in different contexts of biomedical imaging are presented. Moreover, the status of the project for clinical mammography is outlined.
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