Improvement of the homogeneity of magnetic field by the attenuation of a selected component with an open superconducting shield made of commercial tapes

Homogeneous magnetic fields are needed in many applications. The resolution of medical imaging techniques depends on the quality of the magnetic field, as does the efficiency of electron cooling systems used at particle accelerators. Current methods of improving homogeneity require complex arrangements of magnet windings. In this work, the application of commercial superconducting tapes for this purpose is analyzed experimentally and numerically. The shielding effect exhibited by the superconductors can be used to control the shape of the magnetic field. An open magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. To form a shield, the superconducting tapes are wound on a former. Then, it is positioned coaxially inside an electromagnet. The measurements are performed in the DC magnetic field and at zero-field cooling conditions. A numerical model is developed to further analyze the magnetic field. New simplifications and proper constraints allow the use of an axial symmetry despite relatively complex geometry of the shields. Results from the simplified model and obtained experimentally are consistent. The decrease of radial component of the magnetic field and the significant improvement of its homogeneity are observed in a shielded region. The decrease of shielding quality with the increase of an applied magnetic field is observed. Empirical formulas describing the dependence of shielding quality on the geometry and the critical current of the shield are developed

Complex research of the unclosed HTS shield for improving homogeneity of the magnetic field

Abstract Homogeneous magnetic fields are required in different applications. The resolution of MRI techniques depends on the quality of the magnetic field, as well as the efficiency of electron cooling systems used at particle accelerators. Unclosed magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. The shield is a lengthwise winding made from YBCO tapes are wound along a carcass generatrix. Then it is positioned coaxially inside an electromagnet. The measurements were carried out under quasistationary conditions, magnetic fields up to 1 kG at 77K. This paper discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.</jats:p

Complex research of the unclosed HTS shield for improving homogeneity of the magnetic field

Abstract Homogeneous magnetic fields are required in different applications. The resolution of MRI techniques depends on the quality of the magnetic field, as well as the efficiency of electron cooling systems used at particle accelerators. Unclosed magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. The shield is a lengthwise winding made from YBCO tapes are wound along a carcass generatrix. Then it is positioned coaxially inside an electromagnet. The measurements were carried out under quasistationary conditions, magnetic fields up to 1 kG at 77K. This paper discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.</jats:p

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

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

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

SPINAL BLOCKS WITH AND WITHOUT MORPHINE IN WOMEN UNDERGOING HYSTERECTOMIES- A RANDOMIZED STUDY

To study whether a group of patients going through abdominal hysterectomies under general anesthesia could reduce their time of discharge and consumption of parenteral opioids by adding morphine to an intrathecal block. Methods: Sixty seven healthy women, undergoing abdominal hysterectomies. Patients had general anesthesia in combination with spinal blocks. Randomization between intrathecal blocks with morphine (group 1) and without morphine (group 2), in combination with either postoperative intermittent (group 1) or patient controlled analgesia (group 2). Results: The median time to discharge in group 1 was 53 hours and in group two 69 hours. Time of discharge was not statistically significant (p = 0.51). The patients in group 2 had significantly higher visual analogue scores for pain postoperatively. More postoperative opioids were also consumed in that group (p&lt;0.0001). Furthermore, significantly more patients in group 2 compared to group1 indicated that they had suffered from major nausea (p=0.01)