Quantification of the secretory glycoproteins of the subcommissural organ by a sensitive sandwich ELISA with a polyclonal antibody and a set of monoclonal antibodies against the bovine Reissner's fiber

The subcommissural organ (SCO) is an ependymal brain gland that releases glycoproteins into the ventricular cerebrospinal fluid where they condense to form the Reissner's fiber (RF). We have developed a highly sensitive and specific two-antibody sandwich enzyme-linked immunosorbent assay (ELISA) for the quantification of the bovine SCO secretory material. The assay was based on the use of the IgG fraction of a polyclonal antiserum against the bovine RF as capture antibody and a pool of three peroxidase-labeled monoclonal antibodies that recognize non-overlapping epitopes of the RF glycoproteins as detection antibody. The detection limit was 1 ng/ml and the working range extended from 1 to 4000 ng/ml. The calibration curve, generated with RF glycoproteins, showed two linear segments: one of low sensitivity, ranging from 1 to 125 ng/ml, and the other of high sensitivity between 125 and 4000 ng/ml. This assay was highly reproducible (mean intra- and interassay coefficient of variation 2.2% and 5.3%, respectively) and its detectability and sensitivity were higher than those of ELISAs using exclusively either polyclonal or monoclonal antibodies against RF glycoproteins. The assay succeeded in detecting and measuring secretory material in crude extracts of bovine SCO, culture medium supernatant of SCO explants and incubation medium of bovine RF; however, soluble secretory material was not detected in bovine cerebrospinal fluid

Mechanical Design Analysis of MQXFB, the 7.2-m-Long Low-β Quadrupole for the High-Luminosity LHC Upgrade

As part of the High-Luminosity Large Hadron Collider (LHC) Project, a set of Nb Snquadrupoles are being developed, aiming to enhance the performance of the inner triplets. The new magnets, identified as MQXFA and MQXFB, will share the same cross section with two different lengths, 4.2 and 7.2 m, respectively. During the magnet development, three short models were tested, along with a number of mechanical models, demonstrating the capability of the magnet cross section to achieve the specified performances. The same performances are now required for the full-length magnets. To ensure this, the authors studied the impact of the magnet length on the capability of the structure to provide an adequate support to the coils. Finite element and simplified analytical models were used to evaluate the impact of the magnet length on the stresses in the magnet ends and coil elongation during powering. The models were calibrated using the results from the short model tests, and used to provide an indication on the required prestress and its foreseen impact on the magnet performance.

Second-Generation Coil Design of the Nb3Sn low-β Quadrupole for the High Luminosity LHC

As part of the Large Hadron Collider (LHC) Luminosity upgrade program, the U.S.-LHC Accelerator Research Program collaboration and CERN are working together to design and build a 150-mm aperture Nb3Sn quadrupole for the LHC interaction regions. A first series of 1.5-m-long coils was fabricated and assembled in a first short model. A detailed visual inspection of the coils was carried out to investigate cable dimensional changes during heat treatment and the position of the windings in the coil straight section and in the end region. The analyses allow identifying a set of design changes which, combined with a fine tune of the cable geometry and a field quality optimization, were implemented in a new second-generation coil design. In this paper, we review the main characteristics of the first generation coils, describe the modification in coil layout and discuss their impact on parts design and magnet analysis

Assembly of a Mechanical Model of MQXFB, the 7.2-m-Long Low-β Quadrupole for the High-Luminosity LHC Upgrade

The Nb Sn low-β quadrupole MQXF is being developed as a part of the High-Luminosity large hadron collider (LHC) upgrade project. The magnet will be produced in two different configurations, sharing the same cross section but with different lengths. A 7.2-m mechanical model of MQXFB was recently assembled at european organization for nuclear research (CERN) with one copper coil, two low-grade coils, and one rejected coil. Coil dimensions were measured with a portable coordinate measurement machine. The coil pack shimming was designed in order to optimize the field quality and the contacts between the coils and the collars. The azimuthal preload target was defined using the short models experience. The mechanical behavior during loading was monitored by means of strain gauges. The results demonstrated that the structure can provide the required prestress to the coils.

Insertion Magnets

Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report. The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.Comment: 19 pages, Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Repor

Overview of the Quench Heater Performance for MQXF, the Nb3Sn Low-β Quadrupole for the High Luminosity LHC

In the framework of the high-luminosity upgrade of the Large Hadron Collider, the U.S. LARP collaboration and CERN are jointly developing a 150 mm aperture Nb Sn quadrupole for the LHC interaction regions. Due to the large stored energy density and the low copper stabilizer section, the quench protection of these magnets is particularly challenging, relying on a combination of quench heaters attached to the coil surface and coupling loss induced quench (CLIQ) units electrically connected to the coils. This paper summarizes the performance of the quench heater strips in different configurations relevant to machine operation. The analysis is focused on the inner layer quench heaters, where several heater strips failed during powering tests. Failure modes are discussed in order to address the technology issues and provide guidance for future tests.

Optimizing the use of pressurized bladders for the assembly of HL-LHC MQXFB magnets

The use of pressurized bladders for stress control of superconducting magnets was firstly proposed at Lawrence Berkeley National Laboratory (LBNL) in the early 2000s. Since then, the so-called bladders and keys procedure has become one of the reference techniques for the assembly of high-field accelerator magnets and demonstrators. Exploiting the advantages of this method is today of critical importance for Nb3Sn-based accelerator magnets, whose production requires the preservation of tight stress targets in the superconducting coils to limit the effects of the strain sensitivity and brittleness of the conductor. The present manuscript reports on the results of an experimental campaign focused on the optimization of the bladders and keys assembly process in the MQXFB quadrupoles. These 7.2 m long magnets shall be among the first Nb3Sn cryomagnets to be installed in a particle accelerator as a part of the High Luminosity upgrade of the LHC. One of the main practical implications of the bladders technique, especially important when applied to long magnets like MQXFB, is that to insert the loading keys, the opening of a certain clearance in the support structure is required. The procedure used so far for MQXF magnets involved an overstress in the coils during bladder inflation. The work presented here shows that such an overshoot can be eliminated thanks to additional bladders properly positioned in the structure. This optimized method was validated in a short model magnet and in a full-length mechanical model, becoming the new baseline for the series production at CERN. Furthermore, the results are supported by numerical predictions using Finite Element models

Arsenic exposure, diabetes-related genes and diabetes prevalence in a general population from Spain

Inorganic arsenic exposure may be associated with diabetes, but the evidence at low-moderate levels is not sufficient. Polymorphisms in diabetes-related genes have been involved in diabetes risk. We evaluated the association of inorganic arsenic exposure on diabetes in the Hortega Study, a representative sample of a general population from Valladolid, Spain. Total urine arsenic was measured in 1451 adults. Urine arsenic speciation was available in 295 randomly selected participants. To account for the confounding introduced by non-toxic seafood arsenicals, we designed a multiple imputation model to predict the missing arsenobetaine levels. The prevalence of diabetes was 8.3%. The geometric mean of total arsenic was 66.0 µg/g. The adjusted odds ratios (95% confidence interval) for diabetes comparing the highest with the lowest tertile of total arsenic were 1.76 (1.01, 3.09) and 2.14 (1.47, 3.11) before and after arsenobetaine adjustment, respectively. Polymorphisms in several genes including IL8RA, TXN, NR3C2, COX5A and GCLC showed suggestive differential associations of urine total arsenic with diabetes. The findings support the role of arsenic on diabetes and the importance of controlling for seafood arsenicals in populations with high seafood intake. Suggestive arsenic-gene interactions require confirmation in larger studies