Optically Based Charge Injection System for Ionization Detectors

An optically coupled charge injection system for ionization based radiation detectors which allows a test charge to be injected without the creation of ground loops has been developed. An ionization like signal from an external source is brought into the detector through an optical fiber and injected into the electrodes by means of a photodiode. As an application example, crosstalk measurements on a liquid Argon electromagnetic calorimeter readout electrodes were performed

Progress on DC-DC Converters for a Silicon Tracker for the sLHC Upgrade

There is a need for DC-DC converters which can operate in the extremely harsh environment of the sLHC Si Tracker. The environment requires radiation qualification to a total ionizing radiation dose of 50 Mrad and a displacement damage fluence of 5 x 1014 /cm2 of 1 MeV equivalent neutrons. In addition a static magnetic field of 2 Tesla or greater prevents the use of any magnetic components or materials. In February 2007 an Enpirion EN5360 was qualified for the sLHC radiation dosage but the converter has an input voltage limited to a maximum of 5.5V. From a systems point of view this input voltage was not sufficient for the application. Commercial LDMOS FETs have developed using a 0.25 μm process which provided a 12 volt input and were still radiation hard. These results are reported here and in previous papers. Plug in power cards with ×10 voltage ratio are being developed for testing the hybrids with ABCN chips. These plug-in cards have air coils but use commercial chips that are not designed to be radiation hard. This development helps in evaluating system noise and performance. GaN FETs are tested for radiation hardness to ionizing radiation and displacement damage and preliminary results are given

Eye-Light on Age-Related Macular Degeneration: Targeting Nrf2-Pathway as a Novel Therapeutic Strategy for Retinal Pigment Epithelium

open6noThis work was supported by the University of Pavia [to MA, grant number BSR1744747; 2017] and the Italian Ministry of University and Research [to MA, FFABR2017]. The University of Bologna is acknowledged by MR [Grants from RFO].Age-related macular degeneration (AMD) is a common disease with a multifactorial aetiology, still lacking effective and curative therapies. Among the early events triggering AMD is the deterioration of the retinal pigment epithelium (RPE), whose fundamental functions assure good health of the retina. RPE is physiologically exposed to high levels of oxidative stress during its lifespan; thus, the integrity and well-functioning of its antioxidant systems are crucial to maintain RPE homeostasis. Among these defensive systems, the Nrf2-pathway plays a primary role. Literature evidence suggests that, in aged and especially in AMD RPE, there is an imbalance between the increased pro-oxidant stress, and the impaired endogenous detoxifying systems, finally reverberating on RPE functions and survival. In this in vitro study on wild type (WT) and Nrf2-silenced (siNrf2) ARPE-19 cells exposed to various AMD-related noxae (H2O2, 4-HNE, MG132 + Bafilomycin), we show that the Nrf2-pathway activation is a physiological protective stress response, leading downstream to an up-regulation of the Nrf2-targets HO1 and p62, and that a Nrf2 impairment predisposes the cells to a higher vulnerability to stress. In search of new pharmacologically active compounds potentially useful for AMD, four nature-inspired hybrids (NIH) were individually characterized as Nrf2 activators, and their pharmacological activity was investigated in ARPE-19 cells. The Nrf2 activator dimethyl-fumarate (DMF; 10 μM) was used as a positive control. Three out of the four tested NIH (5 μM) display both direct and indirect antioxidant properties, in addition to cytoprotective effects in ARPE-19 cells under pro-oxidant stimuli. The observed pro-survival effects require the presence of Nrf2, with the exception of the lead compound NIH1, able to exert a still significant, albeit lower, protection even in siNrf2 cells, supporting the concept of the existence of both Nrf2-dependent and independent pathways mediating pro-survival effects. In conclusion, by using some pharmacological tools as well as a reference compound, we dissected the role of the Nrf2-pathway in ARPE-19 stress response, suggesting that the Nrf2 induction represents an efficient defensive strategy to prevent the stress-induced damage.openCatanzaro M.; Lanni C.; Basagni F.; Rosini M.; Govoni S.; Amadio M.Catanzaro M.; Lanni C.; Basagni F.; Rosini M.; Govoni S.; Amadio M

Standard and Light-Cycler PCR methods for animal DNA species detection in animal feedstuffs

In this work four species-specific primers and probes were designed and evaluated for the detection and quantification of bovine, ovine, swine and chicken mitochondrial DNA in feeds. PCR primers were optimized using conventional and Real Time PCR, to detect short species-specific sequences amplifiable from heat treated material. Both methods confirmed the high specificity of the primers designed. Real time quantitative PCR assay allowed the detection of as few as 0.01 ng and 0.05 ng of ovine and bovine genomic DNA, respectively. The detection limit for swine and chicken genomic DNA was 0.5 ng. Sensitivity levels observed in DNA extracted from meat samples processed according to EU legislation were different compared to those in genomic DNAs previously described. They resulted in swine 5 fg of MBM DNA, in chicken 25 ng, in ovine and bovine 50 ng. We confirmed the efficiency and specificity of primers in RT-PCR to detect 0.5% of bovine, ovine, swine and chicken MBM in contaminated feedstuffs. (C) 2007 Elsevier Ltd. All rights reserved

Position resolution and particle identification with the ATLAS EM calorimeter

In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

Both 3,3′,5-triiodothyronine and 3,5-diodo-L-thyronine are able to repair mitochondrial DNA damage but by different mechanisms

This study evaluated the effect of 3,5-diiodo-L-thyronine (T2) and 3,5,3′-triiodo-L-thyronine (T3) on rat liver mitochondrial DNA (mtDNA) oxidative damage and repair and to investigate their ability to induce protective effects against oxidative stress. Control rats, rats receiving a daily injection of T2 (N+T2) for 1 week and rats receiving a daily injection of T3 (N+T3) for 1 week, were used throughout the study. In the liver, mtDNA oxidative damage [by measuring mtDNA lesion frequency and expression of DNA polymerase γ (POLG)], mtDNA copy number, mitochondrial biogenesis [by measuring amplification of mtDNA/nDNA and expression of peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α)], and oxidative stress [by measuring serum levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG)] were detected. T2 reduces mtDNA lesion frequency and increases the expression of POLG, and it does not change the mtDNA copy number, the expression of PGC-1α, or the serum levels of 8-OHdG. Therefore, T2, by stimulating the major mtDNA repair enzyme, maintains genomic integrity. Similar to T2, T3 decreases mtDNA lesion frequency but increases the serum levels of 8-OHdG, and it decreases the expression of POLG. Moreover, as expected, T3 increases the mtDNA copy number and the expression of PGC-1α. Thus, in T3-treated rats, the increase of 8-OHdG and the decrease of POLG indicate that there is increased oxidative damage and that the decreased mtDNA lesion frequency might be a consequence of increased mitochondrial biogenesis. These data demonstrate that both T2 and T3 are able to decrease in the liver mtDNA oxidative damage, but they act via different mechanisms

High resolution 3D imaging of living cells with sub-optical wavelength phonons

Label-free imaging of living cells below the optical diffraction limit poses great challenges for optical microscopy. Biologically relevant structural information remains below the Rayleigh limit and beyond the reach of conventional microscopes. Super-resolution techniques are typically based on the nonlinear and stochastic response of fluorescent labels which can be toxic and interfere with cell function. In this paper we present, for the first time, imaging of live cells using sub-optical wavelength phonons. The axial imaging resolution of our system is determined by the acoustic wavelength (λa = λprobe/2n) and not on the NA of the optics allowing sub-optical wavelength acoustic sectioning of samples using the time of flight. The transverse resolution is currently limited to the optical spot size. The contrast mechanism is significantly determined by the mechanical properties of the cells and requires no additional contrast agent, stain or label to image the cell structure. The ability to breach the optical diffraction limit to image living cells acoustically promises to bring a new suite of imaging technologies to bear in answering exigent questions in cell biology and biomedicine

3,5-Diiodo-L-thyronine modulates the expression of genes of lipid metabolism in a rat model of fatty liver.

Recent reports demonstrated that 3,5-diiodo-l-thyronine (T(2)) was able to prevent lipid accumulation in the liver of rats fed a high-fat diet (HFD). In this study, we investigated how the rat liver responds to HFD and T(2) treatment by assessing the transcription profiles of some genes involved in the pathways of lipid metabolism: oxidation, storage and secretion. The mRNA levels of the peroxisome proliferator-activated receptors (PPARα, PPARγ and PPARδ), and of their target enzymes acyl-CoA oxidase and stearoyl-CoA desaturase were evaluated by real-time RT-PCR. Moreover, the expression of the adipose triglyceride lipase involved in lipid mobilisation, of the main PAT proteins acting in lipid droplet (LD) turnover, and of apoprotein B (apo B), the major protein component of very low-density lipoproteins (VLDLs) were analysed. Overall, our data demonstrated that T(2) administration to HFD rats counteracts most of the hepatic transcriptional changes that occurred in response to the excess exogenous fat. In particular, our results suggest that T(2) may prevent the pathways leading to lipid storage in LDs, promote the processes of lipid mobilisation from LDs and secretion as VLDL, in addition to the stimulation of pathways of lipid oxidation. In conclusion, our findings might give an insight into the mechanisms underlying the anti-steatotic ability of T(2) and help to define the potential therapeutic role of T(2) for preventing or treating liver steatosis