Relative luminosity measurement of the LHC with the ATLAS forward calorimeter

In this paper it is shown that a measurement of the relative luminosity changes at the LHC may be obtained by analysing the currents drawn from the high voltage power supplies of the electromagnetic section of the forward calorimeter of the ATLAS detector. The method was verified with a reproduction of a small section of the ATLAS forward calorimeter using proton beams of known beam energies and variable intensities at the U-70 accelerator at IHEP in Protvino, Russia. The experimental setup and the data taking during a test beam run in April 2008 are described in detail. A comparison of the measured high voltage currents with reference measurements from beam intensity monitors shows a linear dependence on the beam intensity. The non-linearities are measured to be less than 0.5 % combining statistical and systematic uncertainties.Comment: 16 page

Construction, assembly and tests of the ATLAS electromagnetic barrel calorimeter

The construction and assembly of the two half barrels of the ATLAS central electromagnetic calorimeter and their insertion into the barrel cryostat are described. The results of the qualification tests of the calorimeter before installation in the LHC ATLAS pit are given

Construction, assembly and testing of the ATLAS hadronic end-cap calorimeter

The construction and assembly of the four wheels of the ATLAS hadronic end-cap calorimeter and their insertion into the two end-cap cryostats are described. The results of the qualification tests prior to installation of the two cryostats in the ATLAS experimental cavern are reviewed

The elimination half-life of crystalloid fluid is shorter in female than in male volunteers: a retrospective population kinetic analysis

BACKGROUND: A recent review article suggests that elimination of infused crystalloid fluid might occur faster in females than in males. To study this question, a population kinetic analysis was performed to compare the turnover of buffered Ringer’s solution when infused at different rates in males and females. METHODS: Data were retrieved from seven series of experiments where 44 intravenous infusions of Ringer’s acetate had been given to female volunteers and 67 to male volunteers. Frequent measurements of the blood hemoglobin and the urinary excretion were used as input in a kinetic two-volume model with micro-constants and covariates, using a nonlinear mixed effects software. The key outcome measure was the rate of irreversible elimination of infused fluid, which was expressed as the half-life, obtained as the excreted urine divided by the modeled plasma volume expansion over time. RESULTS: The half-life amounted to 24 min (95 % confidence interval, 21–27) in the females and 38 min (33–42) in the males. The urinary excretion differed somewhat less than suggested by these figures during the experimental period (3–4 h) because the plasma volume became less expanded in the females. This was due to that fluid that had been distributed peripheral tissues (the interstitium) returned slightly more slowly to the central fluid space (the plasma) in the females. Gender did not serve as a statistically significant covariate to other rate constants in the kinetic model. CONCLUSIONS: The half-life of infused Ringer’s acetate was 60 % longer in healthy male volunteers than in female volunteers. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13293-016-0105-7) contains supplementary material, which is available to authorized users

Bead arrays for antibody and complement profiling reveal joint contribution of antibody isotypes to C3 deposition

The development of antigen arrays has provided researchers with great tools to identify reactivities against self or foreign antigens from body fluids. Yet, these approaches mostly do not address antibody isotypes and their effector functions even though these are key points for a more detailed understanding of disease processes. Here, we present a bead array-based assay for a multiplexed determination of antigen-specific antibody levels in parallel with their properties for complement activation. We measured the deposition of C3 fragments from serum samples to reflect the degree of complement activation via all three complement activation pathways. We utilized the assay on a bead array containing native and citrullinated peptide antigens to investigate the levels of IgG, IgM and IgA autoantibodies along with their complement activating properties in serum samples of 41 rheumatoid arthritis patients and 40 controls. Our analysis revealed significantly higher IgG reactivity against the citrullinated fibrinogen β and filaggrin peptides as well as an IgA reactivity that was exclusive for citrullinated fibrinogen β peptide and C3 deposition in rheumatoid arthritis patients. In addition, we characterized the humoral immune response against the viral EBNA-1 antigen to demonstrate the applicability of this assay beyond autoimmune conditions. We observed that particular buffer compositions were demanded for separate measurement of antibody reactivity and complement activation, as detection of antigen-antibody complexes appeared to be masked due to C3 deposition. We also found that rheumatoid factors of IgM isotype altered C3 deposition and introduced false-positive reactivities against EBNA-1 antigen. In conclusion, the presented bead-based assay setup can be utilized to profile antibody reactivities and immune-complex induced complement activation in a high-throughput manner and could facilitate the understanding and diagnosis of several diseases where complement activation plays role in the pathomechanism

Volume kinetic development and application [Elektronisk resurs]

Background: Fluid therapy is a cornerstone in shock resuscitation in a such as treatment of anesthesia induce down regulation of the circulation and also restores many different types of dehydrated states. Current guidelines for fluid therapy are, however, based on experience, rules of thumb and effect-related end points, such as restoration of physiological parameters, which do not directly represent the volume effect of the fluid. Many efforts have been made to measure the actual volume effect of different fluids. The methods used are mainly based on isotope labeling of substances. Such a method has two inherent limitations. One is that labeling of substances results in volume estimations from the dispersal of the substance in the body, often leading to the conclusion that the volume effect of the fluid acts in the same space. The second limitation is the stationary result for each labeled substance infused. Such a method is not suited for dynamic analysis of fluid volume dispersal and elimination, whereas volume kinetics provides a time resolution. Methods: This thesis is based on the analysis of serial measurements of blood hemoglobin concentration in conjunction with intravenous fluid infusion, analyzed by a lest sqare regression curve rifting procedure. In paper I, the dilution-time profile was used to calculate the relative intravascular percentage of the infused amount of volume. In papers II-V, the analysis was based on volume kinetics using four different models. Results: Paper I showed that hypotension might modulate the preference of fluid to remain in the intravascular compartment. Papers II-V showed similar volume kinetic parameter results when no bleeding was induced and that the obtained volumes were significantly smaller than the expected extracellular spaces. Paper IV showed that hemorrhage resulted in a clearly reduced rate of elimination and that the V1 reduced by about the hemorrhaged volume. The use of urine volume as an input measurement in the two-volume model was justified when there was a high degree of intercorrelation between the elimination rate parameter and the parameter for the peripheral fluid space (paper III). Paper V compared the efficiency of five different infusion fluids and showed that volume kinetics could be used to analyze of the mechanism behind altered fluid handling. Conclusion: Time dilution profiles can be used to analyze the functional mechanisms controlling fluid distribution and elimination. The obtained parameters were the about same in experiments using different infusion volumes and rates. When strong parameter intercorrelation occurs, it is justified to use the urine volume in the calculation to reduce the estimated parameters so as to enhance the precision in the remaining ones. Additionally, serial analyze of blood dilution and volume kinetic interpretations were useful for creating a dynamic dosage scheme for hemorrhage in volunteers and also in the comparison between different fluids pinpointing the specific functional mechanisms causing differences in fluid handling. Thus, volume kinetics provides a new tool for the analysis of fluid dynamics. Volume kinetics is also a tool for the analysis of the mechanisms of pathological fluid handling, such as in septicemia, anesthesia, or heart failure (comparative studies)