Remote Inspection, Measurement and Handling for LHC

Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-date and future development plans

TRANSPORT AND INSTALLATION OF CRYO-MAGNETS IN CERN'S LARGE HADRON COLLIDER TUNNEL

The arcs of the Large Hadron Collider (LHC) will contain around 1700 main superconducting dipoles and quadrupoles. The long and heavy magnets are supported on fragile composite support posts inside a cryostat to reduce the heat in-leak to the magnets' super fluid helium bath. The presence of fragile components and the need to avoid geometry changes make the cryo-magnets very difficult to handle and transport. The transport and installation of the LHC cryo-magnets in the LEP tunnels originally designed for smaller, lighter LEP magnets has required development of completely new handling solutions. The paper explains the constraints imposed by the cryo-magnet characteristics, the existing tunnel infrastructure and schedule considerations. The development and realisation of transport and handling solutions are described, starting from conceptual design, through manufacture and testing to the installation of the first cryo-magnet. Integration studies to verify and reserve space needed for manoeuvre and the preparation of the infrastructure for transport and installation operations are also presented. The paper includes conclusions and some of the lessons learned

Otras voces: cartilla de citación

Esta cartilla pretende incentivar en los eafitenses una cultura del respeto por los derechos de autor y la honestidad académica . Esta contiene los estilos de citación más utilizados para la realización de trabajos académicos, además de dar las indicaciones sobre la localización de estos en línea y en la Biblioteca

Ultrasound propagation in the sodium borosilicate glass system

Measurements of ultrasound wave velocity and attenuation are used to investigate the structure of Na(_2)O-B(_2)O(_3)-SiO(_2) glasses. The propagation characteristics of longitudinal and shear waves between 1.3 K and 400 K at frequencies between 12 MHz and 60 MHz are dominated by a broad and intense acoustic loss peak whose height and position are frequency sensitive. Of the previously proposed models for the mechanism of the acoustic loss, which also occurs in other inorganic glasses, the ultrasound absorption is most consistent with a thermally activated structural relaxation involving the transverse vibration of an oxygen atom between two potential wells of equal or nearly equal depth in the plane of a non linear cation-oxygen-cation bond. An Akhieser type acoustic phonon-thermal phonon interaction is shown no to be responsible for the observed loss. An attempt frequency of l0(^13)Hz and a distribution of activation energies out to 12 K cal/mole but with a mean value of about 3 K cal/mole are found for the relaxation mechanism in the Na(_2)O-B(_2)O(_3)-SiO(_2) glasses. The absolute value and the temperature coefficient of ultrasound velocity, and the maximum acoustic loss are strongly dependent on the total Na(_2)O content of the glasses. Ultrasound propagation characteristics are also affected by phase-separation inducing heat treatment: the steady rise in the height of the loss peak and the complex behaviour of the ultrasound velocity with time of treatment suggest that structural rearrangement is still taking place in the individual glassy phases even after long periods of heat treatment. Also reported is the existence of a small acoustic loss peak at liquid helium temperatures in the Na(_2)O-B(_2)O(_2)-SiO(_2) glasses. This feature of the ultrasound absorption spectrum is characteristic of many tetrahedrally coordinated inorganic glasses. On the assumption of an Arrhenius activation process for this loss peak, an activation energy of 60 ± 15 cal/mole and an attempt frequency of 10(^10) to 10(^12) Hz is indicated

Genetic Loci associated with C-reactive protein levels and risk of coronary heart disease.

Plasma levels of C-reactive protein (CRP) are independently associated with risk of coronary heart disease, but whether CRP is causally associated with coronary heart disease or merely a marker of underlying atherosclerosis is uncertain. To investigate association of genetic loci with CRP levels and risk of coronary heart disease. We first carried out a genome-wide association (n = 17,967) and replication study (n = 13,615) to identify genetic loci associated with plasma CRP concentrations. Data collection took place between 1989 and 2008 and genotyping between 2003 and 2008. We carried out a mendelian randomization study of the most closely associated single-nucleotide polymorphism (SNP) in the CRP locus and published data on other CRP variants involving a total of 28,112 cases and 100,823 controls, to investigate the association of CRP variants with coronary heart disease. We compared our finding with that predicted from meta-analysis of observational studies of CRP levels and risk of coronary heart disease. For the other loci associated with CRP levels, we selected the most closely associated SNP for testing against coronary heart disease among 14,365 cases and 32,069 controls. Risk of coronary heart disease. Polymorphisms in 5 genetic loci were strongly associated with CRP levels (% difference per minor allele): SNP rs6700896 in LEPR (-14.8%; 95% confidence interval [CI], -17.6% to -12.0%; P = 6.2 x 10(-22)), rs4537545 in IL6R (-11.5%; 95% CI, -14.4% to -8.5%; P = 1.3 x 10(-12)), rs7553007 in the CRP locus (-20.7%; 95% CI, -23.4% to -17.9%; P = 1.3 x 10(-38)), rs1183910 in HNF1A (-13.8%; 95% CI, -16.6% to -10.9%; P = 1.9 x 10(-18)), and rs4420638 in APOE-CI-CII (-21.8%; 95% CI, -25.3% to -18.1%; P = 8.1 x 10(-26)). Association of SNP rs7553007 in the CRP locus with coronary heart disease gave an odds ratio (OR) of 0.98 (95% CI, 0.94 to 1.01) per 20% lower CRP level. Our mendelian randomization study of variants in the CRP locus showed no association with coronary heart disease: OR, 1.00; 95% CI, 0.97 to 1.02; per 20% lower CRP level, compared with OR, 0.94; 95% CI, 0.94 to 0.95; predicted from meta-analysis of the observational studies of CRP levels and coronary heart disease (z score, -3.45; P < .001). SNPs rs6700896 in LEPR (OR, 1.06; 95% CI, 1.02 to 1.09; per minor allele), rs4537545 in IL6R (OR, 0.94; 95% CI, 0.91 to 0.97), and rs4420638 in the APOE-CI-CII cluster (OR, 1.16; 95% CI, 1.12 to 1.21) were all associated with risk of coronary heart disease. The lack of concordance between the effect on coronary heart disease risk of CRP genotypes and CRP levels argues against a causal association of CRP with coronary heart disease

Probiotic Use and Their Effect on IBS Symptoms: A Review of Literature

Aim: Probiotics are an attractive therapy for patients dealing with irritable bowel syndrome (IBS) in light of decreased financial costs, fewer medications, and a more natural approach. In this review of literature our purpose was to answer the following PICO question: “In adults with IBS, how does supplemental probiotic use compared to no probiotic use affect IBS symptoms?” Methods: In our review of the literature, the databases searched were CINAHL, MEDLINE, Cochrane, PubMed, Google Scholar, and Onesearch from the years 2008-2018; from which we found ten articles published within the last six years. Results: Seventy percent of the articles reviewed for our research identified that both the experimental (probiotic) and control (placebo) groups showed equal significant improvement in the management of IBS symptoms. Sixty percent of our articles studying multispecies versus monospecies probiotic therapy observed a greater therapeutic response when using probiotics in combination rather than individually. Lastly, 60% observed a therapeutic response in the reduction of IBS symptoms. Conclusion: The results of our review indicated that there was significant evidence for the use of probiotics in alleviating symptoms of IBS. However, the benefit of probiotics was equal to that of the placebo or not significantly greater. Therefore, we concluded that a pilot of change in practice should be considered, but there is still a need for further investigation on this topic. Keywords: Probiotics, Efficacy, Irritable Bowel Syndrome, Treatment, Management, Therapeutic, Effective

Genetically encoded photocross-linkers determine the biological binding site of exendin-4 peptide in the N-terminal domain of the intact human glucagon-like peptide-1 receptor (GLP-1R)

The glucagon-like peptide-1 receptor (GLP-1R) is a key therapeutic target in the management of type II diabetes mellitus, with actions including regulation of insulin biosynthesis and secretion, promotion of satiety, and preservation of β-cell mass. Like most class B G protein-coupled receptors (GPCRs), there is limited knowledge linking biological activity of the GLP-1R with the molecular structure of an intact, full-length, and functional receptor·ligand complex. In this study, we have utilized genetic code expansion to site-specifically incorporate the photoactive amino acid p-azido-l-phenylalanine (azF) into N-terminal residues of a full-length functional human GLP-1R in mammalian cells. UV-mediated photolysis of azF was then carried out to induce targeted photocross-linking to determine the proximity of the azido group in the mutant receptor with the peptide exendin-4. Cross-linking data were compared directly with the crystal structure of the isolated N-terminal extracellular domain of the GLP-1R in complex with exendin(9–39), revealing both similarities as well as distinct differences in the mode of interaction. Generation of a molecular model to accommodate the photocross-linking constraints highlights the potential influence of environmental conditions on the conformation of the receptor·peptide complex, including folding dynamics of the peptide and formation of dimeric and higher order oligomeric receptor multimers. These data demonstrate that crystal structures of isolated receptor regions may not give a complete reflection of peptide/receptor interactions and should be combined with additional experimental constraints to reveal peptide/receptor interactions occurring in the dynamic, native, and full-length receptor state

An Experimental Area for Short Baseline Neutrino Physics on the CERN Neutrino Beam to Gran Sasso

A new neutrino beam line from the CERN SPS to the Gran Sasso laboratory in Italy is presently under study. The new neutrino beam will allow both long baseline and short baseline neutrino oscillation experiments to be performed. This report presents a conceptual design of the short baseline experimental area to be located at a distance of 1858 m from the neutrino target

Genetic Variation in the SLC8A1 Calcium Signaling Pathway Is Associated With Susceptibility to Kawasaki Disease and Coronary Artery Abnormalities.

BACKGROUND: Kawasaki disease (KD) is an acute pediatric vasculitis in which host genetics influence both susceptibility to KD and the formation of coronary artery aneurysms. Variants discovered by genome-wide association studies and linkage studies only partially explain the influence of genetics on KD susceptibility. METHODS AND RESULTS: To search for additional functional genetic variation, we performed pathway and gene stability analysis on a genome-wide association study data set. Pathway analysis using European genome-wide association study data identified 100 significantly associated pathways (P<5×10-4). Gene stability selection identified 116 single nucleotide polymorphisms in 26 genes that were responsible for driving the pathway associations, and gene ontology analysis demonstrated enrichment for calcium transport (P=1.05×10-4). Three single nucleotide polymorphisms in solute carrier family 8, member 1 (SLC8A1), a sodium/calcium exchanger encoding NCX1, were validated in an independent Japanese genome-wide association study data set (meta-analysis P=0.0001). Patients homozygous for the A (risk) allele of rs13017968 had higher rates of coronary artery abnormalities (P=0.029). NCX1, the protein encoded by SLC8A1, was expressed in spindle-shaped and inflammatory cells in the aneurysm wall. Increased intracellular calcium mobilization was observed in B cell lines from healthy controls carrying the risk allele. CONCLUSIONS: Pathway-based association analysis followed by gene stability selection proved to be a valuable tool for identifying risk alleles in a rare disease with complex genetics. The role of SLC8A1 polymorphisms in altering calcium flux in cells that mediate coronary artery damage in KD suggests that this pathway may be a therapeutic target and supports the study of calcineurin inhibitors in acute KD