Design and Assembly of a Large-aperture Nb3Sn Cos-theta Dipole Coil with Stress Management in Dipole Mirror Configuration

The stress-management cos-theta (SMCT) coil is a new concept which has been proposed and is being developed at Fermilab in the framework of US Magnet Development Program (US-MDP) for high-field and/or large-aperture accelerator magnets based on low-temperature and high-temperature superconductors. The SMCT structure is used to reduce large coil deformations under the Lorentz forces and, thus, the excessively large strains and stresses in the coil. A large-aperture Nb3Sn SMCT dipole coil has been developed and fabricated at Fermilab to demonstrate and test the SMCT concept including coil design, fabrication technology and performance. The first SMCT coil has been assembled with 60-mm aperture Nb3Sn coil inside a dipole mirror configuration and will be tested separately and in series with the insert coil. This paper summarizes the large-aperture SMCT coil design and parameters and reports the coil fabrication steps and its assembly in dipole mirror configuration

Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands

Recent advancements in the critical current density (Jc) of Nb$_{3}$Sn conductors, coupled with a large effective filament size, have drawn attention to the problem of magnetothermal instabilities. At low magnetic fields, the quench current of such high Jc Nb$_{3}$Sn strands is significantly lower than their critical current because of the above-mentioned instabilities. An adiabatic model to calculate the minimum current at which a strand can quench due to magneto-thermal instabilities is developed. The model is based on an 'integral' approach already used elsewhere [1]. The main difference with respect to the previous model is the addition of the self-field effect that allows to describe premature quenches of non-magnetized Nb$_{3}$Sn strands and to better calculate the quench current of strongly magnetized strands. The model is in good agreement with experimental results at 4.2 K obtained at Fermilab using virgin Modified Jelly Roll (MJR) strands with a low Residual Resistivity Ratio (RRR) of the stabilizing copper. The prediction of the model at 1.9 K and the results of the tests carried out at CERN, at 4.2 K and 1.9 K, on a 0.8 mm Rod Re-Stack Process (RRP) strand with a low RRR value are discussed. At 1.9 K the test revealed an unexpected strand performance at low fields that might be a sign of a new stability regime

Assessing the Association between Serum Ferritin, Transferrin Saturation, and C-Reactive Protein in Northern Territory Indigenous Australian Patients with High Serum Ferritin on Maintenance Haemodialysis

Copyright © 2017 SandawanaWilliam Majoni et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Objective. To determine the significance of high serum ferritin observed in Indigenous Australian patients on maintenance haemodialysis in the Northern Territory, we assessed the relationship between ferritin and transferrin saturation (TSAT) as measures of iron status and ferritin and C-reactive protein (CRP) as markers of inflammation. Methods. We performed a retrospective cohort analysis of data from adult patients (≥18 years) on maintenance haemodialysis (>3 months) from 2004 to 2011. Results. There were 1568 patients. The mean age was 53.9 (11.9) years. 1244 (79.3%) were Indigenous. 44.2% () were male. Indigenous patients were younger (mean age [52.3 (11.1) versus 57.4 (15.2), ]) and had higher CRP [14.7 mg/l (7–35) versus 5.9 mg/l (1.9–17.5), ], higher median serum ferritin [1069 µg/l (668–1522) versus 794.9 µg/l (558.5–1252.0), ], but similar transferrin saturation [26% (19–37) versus 28% (20–38), ]. We observed a small positive correlation between ferritin and TSAT (, ), no correlation between ferritin and CRP ( = 0.001, ), and positive association between high serum ferritin and TSAT (), Indigenous ethnicity (), urea reduction ratio (), and gender () after adjustment in mixed regression analysis. Conclusion. Serum ferritin and TSAT may inadequately reflect iron status in this population. The high ferritin was poorly explained by inflammation

High Energy & High Luminosity γγ\gamma\gamma Colliders

With the best of modern standard lasers, high-energy $\gamma\gamma$ colliders from electron beams of E larger than 250 GeV are only possible at the expense of photon luminosity, i.e. 10 times lower than for photon colliders at c.m. energies below 0.5 TeV. For existing state-of-the art lasers, an optimistic upper energy limit for x=4.8 is an electron beam of less than 250 GeV. This Snowmass21 Contributed Paper shows how Free Electron Lasers (FEL) pave the way for High Energy & High Luminosity $\gamma\gamma$ colliders. We present and assess a conceptual design study of a FEL with wavelength of 2.4 $\mu$m and an x-factor in the range of 2 to 40, to maximize the luminosity of a $\gamma\gamma$ collider as second interaction region of 0.5 TeV to 10 TeV c.m. $e^+e^-$ colliders.Comment: Contribution to Snowmass 202

Linear and profilometric changes of the mucosa following soft tissue augmentation in the zone of aesthetic priority:A systematic review and meta-analysis

OBJECTIVES: To assess the outcomes of soft tissue augmentation, in terms of change in level and thickness of mid-buccal mucosa, at implants sites in the zone of the aesthetic priority. MATERIAL AND METHODS: MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials databases were searched (last search on 1 June 2020). Inclusion criteria were studies reporting outcomes of different materials and timing of grafting in patients undergoing soft tissue augmentation at implant sites in the aesthetic zone with a follow-up of ≥1 year after implant placement. Outcome measures assessed included changes in level and thickness of mid-buccal mucosa, implant survival, peri-implant health and patients' satisfaction. RESULTS: Eighteen out of 2,185 articles fulfilled the inclusion criteria. Meta-analysis revealed a significant difference in vertical mid-buccal soft tissue change (0.34 mm, 95% CI: 0.13-0.56, p = .002) and mid-buccal mucosa thickness (0.66 mm, 95% CI: 0.35-0.97, p < .001) following immediate implant placement in favour of the use of a graft versus no graft. Mean difference in mid-buccal mucosa level following delayed implant placement (0.17 mm, 95% CI: 0.01-0.34, p = .042) was also in favour of the use of a graft versus no graft. With regard to mucosa thickness, the use of a graft was not in favour compared with no graft following delayed implant placement (0.22 mm, 95% CI: -0.04-0.47, p = .095). Observed changes remained stable in the medium term. CONCLUSION: Soft tissue augmentation in the zone of the aesthetic priority results in less recession and a thicker mid-buccal mucosa following immediate implant placement and less recession in mid-buccal mucosa following delayed implant placement compared with no graft

Jagged2 controls the generation of motor neuron and oligodendrocyte progenitors in the ventral spinal cord

In the developing spinal cord, motor neurons (MNs) and oligodendrocytes arise sequentially from a common pool of progenitors. However, the genetic network responsible for this neurogenesis to gliogenesis switch is largely unknown. A transcriptome analysis identified the Notch ligand Jagged2 (JAG2) as a Sonic hedgehog-regulated factor transiently expressed in MN progenitors (pMNs). In vivo loss- and gain-of-function experiments show that JAG2 schedules the differentiation of the pMN progenitors. At early developmental stages, Olig2 expressing pMN progenitors that enter the differentiation pathway exclusively generate MNs. At these times, the activation of the Notch pathway by JAG2 maintains selected pMN progenitors in an undifferentiated state by two mechanisms; first it inhibits MN generation by reducing Olig2 proteins levels, and second it directly inhibits the premature generation of oligodendrocyte progenitors (OLPs) by maintaining high levels of Hes5. Later, extinction of JAG2 from the pMN results in the loss of Hes5 expression, heralding the gliogenic phase of pMN progenitors. Strikingly, downregulation of JAG2 in pMN progenitors is sufficient to promote the precocious generation of OLPs. Together these data provide evidence that JAG2 is a key regulator of the timely and ordered generation of two of the defining cell types in the spinal cord, MNs and OLPs

Design of a Probe for Strain Sensitivity Studies of Critical Current Densities in SC Wires and Tapes

The design of a variable-temperature probe used to perform strain sensitivity measurements on LTS wires and HTS wires and tapes is described. The measurements are intended to be performed at liquid helium temperatures (4.2 K). The wire or tape to be measured is wound and soldered on to a helical spring device, which is fixed at one end and subjected to a torque at the free end. The design goal is to be able to achieve {+-} 0.8 % strain in the wire and tape. The probe is designed to carry a current of 2000A

Patch angioplasty during carotid endarterectomy using different materials has similar clinical outcomes

OBJECTIVE: Patch angioplasty during carotid endarterectomy is commonly used to treat carotid artery stenosis. However, the choice of which patch to use is still a matter of debate. Autologous venous material has disadvantages such as wound-related problems at the harvest site and a prolonged intervention time. These limitations can be bypassed when synthetic or biological patches are used. Both materials have been associated with divergent advantages and disadvantages. Therefore, the aim of our study was to compare the long-term follow-up outcomes in patients who received carotid endarterectomy and closure with either bovine pericardial patch or polyester patch. METHODS: A retrospective cohort study was conducted, including all patients who underwent primary carotid endarterectomy and closure with bovine pericardial patch or polyester patch between January 2010 and December 2020 at our tertiary referral center. In 2015, bovine pericardial patch was introduced as an alternative for polyester. The primary outcome was the occurrence of transient ischemic attack or cerebrovascular accident during follow-up and secondary outcomes included restenosis, reintervention, all-cause mortality, and patch infection. Cox proportional hazard models were utilized and hazard ratios with 95%-confidence interval were used to predict the above-mentioned outcomes. RESULTS: 417 carotid endarterectomy patients were included. 254 (61%) patients received bovine pericardial patch and 163 received (39%) polyester. The mean age was 70.2 ± 8.7 and 67% were male. The median follow-up time was 15 (12-27) months for bovine pericardial patch and 42 (16-60) months for polyester (p<0.001). Postoperative hematoma (≤30 days) was significantly lower in the bovine pericardial patch cohort (2% bovine pericardial patch vs 6% polyester; p=0.047). No other significant differences on short-term outcomes were found. Univariable cox regression analyses showed no significant differences between the effect estimates of polyester and bovine pericardial patch on transient ischemic attack or cerebrovascular accident (p=0.106), restenosis (p=0.211), reintervention (p=0.549), and all-cause mortality (p=0.158). No significant differences were found after adjusting for confounders in the multivariable analyses: transient ischemic attack or cerebrovascular accident, (p=0.939), restenosis (p=0.057), reintervention (p=0.193) and all-cause mortality (p=0.742). Three patients with a polyester patch had patch infection compared to none of the patients in the group who received a bovine pericardial patch. CONCLUSION: This large retrospective study showed comparable safety and durability of both bovine pericardial patch and polyester suggesting that both patch types can be safely applied for carotid endarterectomy with patch angioplasty. Patch infection was rare while absent in the bovine pericardial patch group

Study of effects of deformation in Nb3Sn multi filamentary strands

In the process that leads a flawless Nb{sub 3}Sn round strand to become part of a Rutherford cable first, and of a coil next, the same cabling process affects strands of different kinds in different ways, from filament shearing to subelement merging to composite decoupling. Due to plastic deformation, after cabling the filament size distributions in a strand usually change. The average filament size typically increases, as does the width of the distribution. This is consistent with the low field transport current of strands in cables being typically lower and less reproducible than for round strands [1]. To better understand the role of filament size in instabilities and to simulate cabling deformations, strands to be used in cables can be tested by rolling them down to decreasing sizes to cover an ample range of relative deformations. A procedure is herein proposed that uses both microscopic analysis and macroscopic measurements of material properties to study the effects of deformation