78 research outputs found

    Orbit and trajectory measurement with low intensity lead ion beams in the SPS

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    The orbit measurement system of the CERN SPS was designed to measure the position of dense proton beams with an intensity of up to 0.28 A. The lower design limit for the lead ion beam intensity has been fixed at 35mA. This requires a substantial extension of the dynamic range. We describe the properties of the system and its modifications together with the results obtained for sulphur ion beams in the past and lead ions more recently

    LHC BPM design

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    Already in 1997, 8 years before the expected commissioning date of the LHC, the design of the detectors for the orbit system has to be completely terminated. The paper describes the BPM design highlighting the chain of arguments that have led to this particular solution

    Intensity and bunch length measurement for lepton beam in the injection lines of the SPS and LEP

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    We describe a system which is used operationally to measure the absolute intensity of single lepton bunches in a beam transfer line. It is based on the detailed knowledge of every single item of a complex measuring chain that comprises a beam coupler on one end and an acquisition system on the other end. This knowledge can be acquired by a well tested theoretical model and careful measurement of the transfer function of each processing module. A precision better than 3 % can be obtained and no external calibration is required. A value for the bunch length can be deduced from a spectral intensity measurement at two well chosen frequencies

    Performance of the new SPS beam position orbit system (MOPOS)

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    The orbit and trajectory measurement system COPOS of the CERN SPS accelerator has been in operation since the construction of the machine in 1976. Over the years the system has been slightly modified in order to follow the evolving demands of the machine, in particular for its operation as a p-pbar collider and, since 1991, for the acceleration of heavy ions. In 1995 the performance of the system was reviewed and the following shortcomings were identified: - lack of turn-by-turn position measurements due to the 1ms integration time of the voltage to frequency converters used for the analogue to digital conversion (to be compared with a revolution time of 23 ms), - ageing effects on the 200 MHz resonating input filters, which had over the years drifted out of tolerance. As a consequence the signal to noise ratio, the linearity and the absolute precision were affected, - the calibration system based on electromechanical relays had become very unreliable, such that frequent calibrations were no longer possible, - a remote diagnostic for the observation of timing signals relative to the beam signals was missing. For the above reasons a large-scale upgrade program was launched, the results of which are described in the following sections

    Ultra-Rapid Warming Yields High Survival of Mouse Oocytes Cooled to −196°C in Dilutions of a Standard Vitrification Solution

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    Intracellular ice is generally lethal. One way to avoid it is to vitrify cells; that is, to convert cell water to a glass rather than to ice. The belief has been that this requires both the cooling rate and the concentration of glass-inducing solutes be very high. But high solute concentrations can themselves be damaging. However, the findings we report here on the vitrification of mouse oocytes are not in accord with the first belief that cooling needs to be extremely rapid. The important requirement is that the warming rate be extremely high. We subjected mouse oocytes in the vitrification solution EAFS 10/10 to vitrification procedures using a broad range of cooling and warming rates. Morphological survivals exceeded 80% when they were warmed at the highest rate (117,000°C/min) even when the prior cooling rate was as low as 880°C/min. Functional survival was >81% and 54% with the highest warming rate after cooling at 69,000 and 880°C/min, respectively. Our findings are also contrary to the second belief. We show that a high percentage of mouse oocytes survive vitrification in media that contain only half the usual concentration of solutes, provided they are warmed extremely rapidly; that is, >100,000°C/min. Again, the cooling rate is of less consequence

    Genetic polymorphism of the iron-regulatory protein-1 and -2 genes in age-related macular degeneration

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    Iron can be involved in the pathogenesis of AMD through the oxidative stress because it may catalyze the Haber–Weiss and Fenton reactions converting hydrogen peroxide to free radicals, which can induce cellular damage. We hypothesized that genetic polymorphism in genes related to iron metabolism may predispose individuals to the development of AMD and therefore we checked for an association between the g.32373708 G>A polymorphism (rs867469) of the IRP1 gene and the g.49520870 G>A (rs17483548) polymorphism of the IRP2 gene and AMD risk as well as the modulation of this association by some environmental and life-style factors. Genotypes were determined in DNA from blood of 269 AMD patients and 116 controls by the allele-specific oligonucleotide-restriction fragment length polymorphism and the polymerase chain reaction-restriction fragment length polymorphism. An association between AMD, dry and wet forms of AMD and the G/G genotype of the g.32373708 G>A-IRP1 polymorphism was found (OR 3.40, 4.15, and 2.75). On the other hand, the G/A genotype reduced the risk of AMD as well as its dry or wet form (OR 0.23, 0.21, 0.26). Moreover, the G allele of the g.49520870 G>A-IRP2 polymorphism increased the risk of the dry form of the disease (OR 1.51) and the A/A genotype and the A allele decreased such risk (OR 0.43 and 0.66). Our data suggest that the g.32373708 G>A-IRP1 and g.49520870 G>A-IRP2 polymorphisms may be associated with increased risk for AMD

    Application of the rainbow trout derived intestinal cell line (RTgutGC) for ecotoxicological studies: molecular and cellular responses following exposure to copper.

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    There is an acknowledged need for in vitro fish intestinal model to help understand dietary exposure to chemicals in the aquatic environment. The presence and use of such models is however largely restrictive due to technical difficulties in the culturing of enterocytes in general and the availability of appropriate established cell lines in particular. In this study, the rainbow trout (Oncorhynchus mykiss) intestinal derived cell line (RTgutGC) was used as a surrogate for the "gut sac" method. To facilitate comparison, RTgutGC cells were grown as monolayers (double-seeded) on permeable Transwell supports leading to a two-compartment intestinal model consisting of polarised epithelium. This two-compartment model divides the system into an upper apical (lumen) and a lower basolateral (portal blood) compartment. In our studies, these cells stained weakly for mucosubstances, expressed the tight junction protein ZO-1 in addition to E-cadherin and revealed the presence of polarised epithelium in addition to microvilli protrusions. The cells also revealed a comparable transepithelial electrical resistance (TEER) to the in vivo situation. Importantly, the cell line tolerated apical saline (1:1 ratio) thus mimicking the intact organ to allow assessment of uptake of compounds across the intestine. Following an exposure over 72 h, our study demonstrated that the RTgutGC cell line under sub-lethal concentrations of copper sulphate (Cu) and modified saline solutions demonstrated uptake of the metal with saturation levels comparable to short term ex situ gut sac preparations. Gene expression analysis revealed no significant influence of pH or time on mRNA expression levels of key stress related genes (i.e. CYP3A, GST, mtA, Pgp and SOD) in the Transwell model. However, significant positive correlations were found between all genes investigated suggesting a co-operative relationship amongst the genes studied. When the outlined characteristics of the cell line are combined with the division of compartments, the RTgutGC double seeded model represents a potential animal replacement model for ecotoxicological studies. Overall, this model could be used to study the effects and predict aquatic gastrointestinal permeability of metals and other environmentally relevant contaminants in a cost effective and high throughput manner

    Diversity and ethics in trauma and acute care surgery teams: results from an international survey

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    Background: Investigating the context of trauma and acute care surgery, the article aims at understanding the factors that can enhance some ethical aspects, namely the importance of patient consent, the perceptiveness of the ethical role of the trauma leader, and the perceived importance of ethics as an educational subject. Methods: The article employs an international questionnaire promoted by the World Society of Emergency Surgery. Results: Through the analysis of 402 fully filled questionnaires by surgeons from 72 different countries, the three main ethical topics are investigated through the lens of gender, membership of an academic or non-academic institution, an official trauma team, and a diverse group. In general terms, results highlight greater attention paid by surgeons belonging to academic institutions, official trauma teams, and diverse groups. Conclusions: Our results underline that some organizational factors (e.g., the fact that the team belongs to a university context or is more diverse) might lead to the development of a higher sensibility on ethical matters. Embracing cultural diversity forces trauma teams to deal with different mindsets. Organizations should, therefore, consider those elements in defining their organizational procedures. Level of evidence: Trauma and acute care teams work under tremendous pressure and complex circumstances, with their members needing to make ethical decisions quickly. The international survey allowed to shed light on how team assembly decisions might represent an opportunity to coordinate team member actions and increase performance

    Time for a paradigm shift in shared decision-making in trauma and emergency surgery? Results from an international survey

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    Background: Shared decision-making (SDM) between clinicians and patients is one of the pillars of the modern patient-centric philosophy of care. This study aims to explore SDM in the discipline of trauma and emergency surgery, investigating its interpretation as well as the barriers and facilitators for its implementation among surgeons. Methods: Grounding on the literature on the topics of the understanding, barriers, and facilitators of SDM in trauma and emergency surgery, a survey was created by a multidisciplinary committee and endorsed by the World Society of Emergency Surgery (WSES). The survey was sent to all 917 WSES members, advertised through the society’s website, and shared on the society’s Twitter profile. Results: A total of 650 trauma and emergency surgeons from 71 countries in five continents participated in the initiative. Less than half of the surgeons understood SDM, and 30% still saw the value in exclusively engaging multidisciplinary provider teams without involving the patient. Several barriers to effectively partnering with the patient in the decision-making process were identified, such as the lack of time and the need to concentrate on making medical teams work smoothly. Discussion: Our investigation underlines how only a minority of trauma and emergency surgeons understand SDM, and perhaps, the value of SDM is not fully accepted in trauma and emergency situations. The inclusion of SDM practices in clinical guidelines may represent the most feasible and advocated solutions
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