124 research outputs found

    Assessment of dietary background exposure of the Irish adult population to dioxins and PCBs particularly taking into account additional exposure due to the 2008 Irish dioxin food contamination incident

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    Irish monitoring data on PCDD/Fs, DL-PCBs and Marker PCBs were collated and combined with Irish Adult Food Consumption Data, to estimate dietary background exposure of Irish adults to dioxins and PCBs. Furthermore, all available information on the 2008 Irish pork dioxin food contamination incident was collated and analysed with a view to evaluate any potential impact the incident may have had on general dioxin and PCB background exposure levels estimated for the adult population in Ireland. The average upperbound daily intake of Irish adults to dioxins Total WHO TEQ (2005) (PCDD/Fs & DLPCBs) from environmental background contamination, was estimated at 0.3 pg/kg bw/d and at the 95th percentile at 1 pg/kg bw/d. The average upperbound daily intake of Irish adults to the sum of 6 Marker PCBs from environmental background contamination ubiquitous in the environment was estimated at 1.6 ng/kg bw/d and at the 95th percentile at 6.8 ng/kg bw/d. Dietary background exposure estimates for both dioxins and PCBs indicate that the Irish adult population has exposures below the European average, a finding which is also supported by the levels detected in breast milk of Irish mothers. Exposure levels are below health based guidance values and/or Body Burdens associated with the TWI (for dioxins) or associated with a NOAEL (for PCBs). Given the current toxicological knowledge, based on biomarker data and estimated dietary exposure, general background exposure of the Irish adult population to dioxins and PCBs is of no human health concern. In 2008, a porcine fat sample taken as part of the national residues monitoring programme led to the detection of a major feed contamination incidence in the Republic of Ireland. The source of the contamination was traced back to the use of contaminated oil in a direct-drying feed operation system. Congener profiles in animal fat and feed samples showed a high level of consistency and pinpointed the likely source of fuel contamination to be a highly chlorinated commercial PCB mixture. To estimate additional exposure to dioxins and PCBs due to the contamination of pig and cattle herds, collection and a systematic review of all data associated with the contamination incident was conducted. A model was devised that took into account the proportion of contaminated product reaching the final consumer during the 90 day contamination incident window. For a 90 day period, the total additional exposure to Total TEQ (PCDD/F &DL-PCB) WHO (2005) amounted to 407 pg/kg bw/90d at the 95th percentile and 1911 pg/kg bw/90d at the 99th percentile. Exposure estimates derived for both dioxins and PCBs showed that the Body Burden of the general population remained largely unaffected by the contamination incident and approximately 10 % of the adult population in Ireland was exposed to elevated levels of dioxins and PCBs. Whilst people in this 10 % cohort experienced quite a significant additional load to the existing body burden, the estimated exposure values do not indicate approximation of body burdens associated with adverse health effects, based on current knowledge. The exposure period was also limited in time to approximately 3 months, following the FSAI recall of contaminated meat immediately on detection of the contamination. A follow up breast milk study on Irish first time mothers conducted in 2009/2010 did not show any increase in concentrations compared to the study conducted in 2002. The latter supports the conclusion that the majority of the Irish adult population was not affected by the contamination incident

    Measurement of Radiation Damage to 130nm Hybrid Pixel Detector Readout Chips

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    We present the first measurements of the performance of the Medipix3 hybrid pixel readout chip after exposure to significant x-ray flux. Specifically the changes in performance of the mixed mode pixel architecture, the digital periphery, digital to analogue converters and the e-fuse technology were characterised. A high intensity, calibrated x- ray source was used to incrementally irradiate the separate regions of the detector whilst it was powered. This is the first total ionizing dose study of a large area pixel detector fabricated using the 130nm CMOS technology

    A Narrative Review on the Unexplored Potential of Colostrum as a Preventative Treatment and Therapy for Diarrhea in Neonatal Dairy Calves

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    Diarrhea is the leading cause of morbidity and mortality in pre-weaned dairy calves and, as such, represents a significant animal health and welfare concern. Furthermore, digestive disease early in life is associated with several long-term consequences such as reduced growth rate and decreased milk yield during the first lactation, thus generating severe economic losses. The majority of diarrheic cases in young calves are treated with antimicrobials; however, it is necessary to develop alternative treatments, as excessive antimicrobial usage can lead to antimicrobial resistance and can negatively impact the gut microflora of a calf. Bovine colostrum is abundant in immune and bioactive factors that improve immune function and development. This rich and natural combination of immunoglobulins, natural antimicrobial factors, growth factors, anti-inflammatories and nutrients may be an attractive alternative to antimicrobials in the treatment of diarrhea in young dairy calves. There is evidence that supports the use of colostrum as an early treatment for diarrhea in young calves. Future research should investigate its therapeutic and economic effectiveness

    Investigation into levels of dioxins, furans, polychlorinated biphenyls and brominated flame retardants in fishery produce in Ireland

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    The Food Safety Authority of Ireland in collaboration with the Marine Institute and An Board Iascaigh Mhara (Sea Fisheries Board) has carried out a surveillance study of levels of dioxins (PCDDs), furans (PCDFs) polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs), specifically polybrominated diphenylethers (PBDEs) and hexabromocyclododecane (HBCD), in a variety of fish species and fishery products, including fresh and processed products available on the Irish market. The study was undertaken because of concern about the possible effects on human health of these bio-persistent environmental contaminants, known to be present in a number of foodstuffs, notably meat, fish, eggs and dairy products. The study showed that levels of PCDDs and PCDFs in Irish fish and fishery products available on the Irish market were well below existing EC legal limits for these contaminants as laid down in Regulation 466/2001. The lowest level was found in a sample of canned tuna (0.012 ng WHO TEQ/kg whole weight) with the highest level found in a farmed salmon sample (0.82 ng WHO TEQ/kg whole weight), compared with the maximum level under the legislation of 4 ng WHO TEQ/kg whole weight. The levels found were also below the new limits for dioxin-like PCBs (dl-PCBs) and for the sum of WHO-TEQs for PCDDs, PCDFs and dioxin-like PCBs, which were introduced in November, 2006 via Regulation 199/2006. The upper-bound mean levels of PCDDs, PCDFs and dioxin-like PCBs expressed as total WHOTEQs ranged from 0.05 – 2.15 ng/kg WHO TEQ whole weight, which can be compared with the new maximum level of 8 ng WHO TEQ/kg whole weight for the sum of PCDDs, PCDFs and dioxin-like PCBs. Results of this study are in line with those from previous FSAI studies on PCDD and PCDF levels in fish and also in meat, milk and eggs, and indicate relatively low levels of these contaminants in fishery produce available in the Irish marketplace. Reductions of PCDD/Fs and dl-PCBs in Irish farmed salmon were observed in comparison to levels measured in a previous FSAI/MI survey in 2001, in which a mean level of 4.02 ng WHO TEQ/kg whole weight was detected compared with 2.15 ng/kg WHO TEQ whole weight in the present study. Similar observations can be made for levels reported in a study carried out by An Board Iascaigh Mhara in 2004, in which a mean level of 1.75 ng WHO TEQ/kg whole weight was reported. Concentrations of brominated flame retardants were also low. The mean PBDE concentrations ranged from <0.31 to 3.71 µg/kg whole weight in canned tuna to farmed salmon respectively. Although there are no acceptable daily intake (ADI) or maximum limits set for PBDEs or HBCD, the levels of these contaminants found in the study were low, and are very unlikely to present a health risk to Irish consumers. Although fish is a recognised dietary source of PCDDs, PCDFs and PCBs, the health benefits of eating fish are well established, and on the basis of these results the FSAI considers that there is no need to alter current advice on fish consumption. Current advice is that consumers should eat two portions of fish a week, one of which should be oily. The full study report follows, providing further sampling details, analytical methodologies and discussion of the resulting datasets.Funder: Marine Institut

    Precision scans of the pixel cell response of double sided 3D pixel detectors to pion and x-ray beams

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    hree-dimensional (3D) silicon sensors offer potential advantages over standard planar sensors for radiation hardness in future high energy physics experiments and reduced charge-sharing for X-ray applications, but may introduce inefficiencies due to the columnar electrodes. These inefficiencies are probed by studying variations in response across a unit pixel cell in a 55μm pitch double-sided 3D pixel sensor bump bonded to TimePix and Medipix2 readout ASICs. Two complementary characterisation techniques are discussed: the first uses a custom built telescope and a 120GeV pion beam from the Super Proton Synchrotron (SPS) at CERN; the second employs a novel technique to illuminate the sensor with a micro-focused synchrotron X-ray beam at the Diamond Light Source, UK. For a pion beam incident perpendicular to the sensor plane an overall pixel efficiency of 93.0±0.5% is measured. After a 10o rotation of the device the effect of the columnar region becomes negligible and the overall efficiency rises to 99.8±0.5%. The double-sided 3D sensor shows significantly reduced charge sharing to neighbouring pixels compared to the planar device. The charge sharing results obtained from the X-ray beam study of the 3D sensor are shown to agree with a simple simulation in which charge diffusion is neglected. The devices tested are found to be compatible with having a region in which no charge is collected centred on the electrode columns and of radius 7.6±0.6μm. Charge collection above and below the columnar electrodes in the double-sided 3D sensor is observed

    The UA9 experimental layout

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    The UA9 experimental equipment was installed in the CERN-SPS in March '09 with the aim of investigating crystal assisted collimation in coasting mode. Its basic layout comprises silicon bent crystals acting as primary collimators mounted inside two vacuum vessels. A movable 60 cm long block of tungsten located downstream at about 90 degrees phase advance intercepts the deflected beam. Scintillators, Gas Electron Multiplier chambers and other beam loss monitors measure nuclear loss rates induced by the interaction of the beam halo in the crystal. Roman pots are installed in the path of the deflected particles and are equipped with a Medipix detector to reconstruct the transverse distribution of the impinging beam. Finally UA9 takes advantage of an LHC-collimator prototype installed close to the Roman pot to help in setting the beam conditions and to analyze the efficiency to deflect the beam. This paper describes in details the hardware installed to study the crystal collimation during 2010.Comment: 15pages, 11 figure, submitted to JINS

    Ni-62(n,gamma) and Ni-63(n,gamma) cross sections measured at the n_TOF facility at CERN

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    The cross section of the Ni-62(n,gamma) reaction was measured with the time-of-flight technique at the neutron time-of-flight facility n_TOF at CERN. Capture kernels of 42 resonances were analyzed up to 200 keV neutron energy and Maxwellian averaged cross sections (MACS) from kT = 5-100 keV were calculated. With a total uncertainty of 4.5%, the stellar cross section is in excellent agreement with the the KADoNiS compilation at kT = 30 keV, while being systematically lower up to a factor of 1.6 at higher stellar temperatures. The cross section of the Ni-63(n,gamma) reaction was measured for the first time at n_TOF. We determined unresolved cross sections from 10 to 270 keV with a systematic uncertainty of 17%. These results provide fundamental constraints on s-process production of heavier species, especially the production of Cu in massive stars, which serve as the dominant source of Cu in the solar system.Peer reviewedFinal Accepted Versio

    Review of hybrid pixel detector readout ASICs for spectroscopic X-ray imaging

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    Semiconductor detector readout chips with pulse processing electronics have made possible spectroscopic X-ray imaging, bringing an improvement in the overall image quality and, in the case of medical imaging, a reduction in the X-ray dose delivered to the patient. In this contribution we review the state of the art in semiconductor-detector readout ASICs for spectroscopic X-ray imaging with emphasis on hybrid pixel detector technology. We discuss how some of the key challenges of the technology (such as dealing with high fluxes, maintaining spectral fidelity, power consumption density) are addressed by the various ASICs. In order to understand the fundamental limits of the technology, the physics of the interaction of radiation with the semiconductor detector and the process of signal induction in the input electrodes of the readout circuit are described. Simulations of the process of signal induction are presented that reveal the importance of making use of the small pixel effect to minimize the impact of the slow motion of holes and hole trapping in the induced signal in high-Z sensor materials. This can contribute to preserve fidelity in the measured spectrum with relatively short values of the shaper peaking time. Simulations also show, on the other hand, the distortion in the energy spectrum due to charge sharing and fluorescence photons when the pixel pitch is decreased. However, using recent measurements from the Medipix3 ASIC, we demonstrate that the spectroscopic information contained in the incoming photon beam can be recovered by the implementation in hardware of an algorithm whereby the signal from a single photon is reconstructed and allocated to the pixel with the largest deposition
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