YBa2Cu3O7–x (YBCO) coated conductors are emerging as an important option for magnets for energy systems and experimental science. One of the remaining challenges for YBCO superconducting magnets is ...quench protection, i.e. ensuring that the YBCO is not damaged due to a fault condition. One key issue is understanding the underlying causes of degradation during a quench. Here, the microstructure of a quenched, degraded sampled is compared to that of an unquenched control sample. To facilitate microstructural analysis of the YBCO surface, the Cu stabilizer and Ag cap layer were removed by etching. Reactions between the Cu etchant and YBCO proved to be a signature of Ag/YBCO delamination. Two types of pre-existing defects were identified as initiation points of degradation. Defects on the conductor edge resulting in delaminated Ag lead to dendritic flux avalanches and high local heating, which cause further Ag delamination. This self-propagating effect results in dendritic Ag delamination, which is seen through etchant–YBCO reactions. Defects within the YBCO layer result in breaches in the protective Ag layer such that Cu etchant penetrates and reacts with the YBCO. Energy-dispersive X-ray spectroscopy analysis showed similar reactions as in the edge degradation but also showed pure Ag particles, which indicates that the local temperature was sufficient to cause localized Ag melting.
The pulmonary metastasis of osteosarcoma (OS) occurs commonly, which resulted from anoikis resistant (AR) of tumor cells as reported by previous studies, but the exact roles of AR in osteosarcoma ...were not fully studied. Our previous investigations showed fatty acid synthase (FASN) was relating to clinical features of patients with OS. In this study, we aim to explore the functions of FASN in the AR OS cells in vitro and in vivo and study the downstream effectors of FASN. In the present study, we used our established cell model to study the AR. We revealed that AR promoted cell proliferation and migration as determined by colony formation assay and transwell assay. In addition, AR assisted tumor growth in vivo. In the AR cells, the expression of FASN was higher. Thus, we constructed lentiviruses to silence or overexpress FASN in four cell lines to study functions of FASN. Silence of FASN reduced cell colonies and migration while overexpression of FASN increased colonies and migration in suspended cells. Loss of functions of FASN induced cell apoptosis in suspended OS cells while gain of function of FASN suppressed apoptosis as determined by flow cytometry. We found the levels of p-ERK1/2 and Bcl-xL declined when FASN was silenced while they increased when FASN was overexpressed. In addition, results showed that the levels of FASN and its potential related molecules (p-ERK1/2 and Bcl-xL) increased in 143B-AR and MG-63-AR cells. In vivo study showed that inhibition of FASN decreased pulmonary metastasis of OS. In conclusion, we showed that anoikis resistant and FASN as two interactional factors facilitated the progress of osteosarcoma.
This paper reports the commissioning of the vertical magnetic measurement system and the room temperature (warm) and cryogenic (cold) magnetic field measurements of the first full-length (4.2 m) ...quadrupole built by the U.S. Accelerator Upgrade Project (AUP) (formerly the LARP collaboration) for the high luminosity upgrade of the Large Hadron Collider at CERN. The magnet, designated MQXFAP2, is a prototype preceding production for the AUP which will provide ten sets of 8.4-m superconducting insertion region quadrupoles for the Hi-Lumi Upgrade. The quadrupoles will be built by assembling two 4.2-m magnets in a single cryostat. Agreement between Brookhaven National Laboratory's (BNL's) and Lawrence Berkeley National Laboratory's (LBNL's) warm measurement data has indicated that the upgraded vertical magnetic measurement system at Brookhaven National Laboratory is ready for MQXFA magnet production testing. The cold magnetic measurement has been performed and preliminary data analysis has been conducted.
We have tested an intermediate-sized HTS stainless-steel (co-wound) insulated double pancake coil (<inline-formula><tex-math notation="LaTeX">\sim</tex-math></inline-formula>132 turns per coil) and ...discovered dynamic effects during sudden discharge on both millisecond and second scales. For soft break, the power supply is turned off suddenly but the shunt resistor (164 milliohm) is still connected; for hard break, a high voltage contactor is used to suddenly open the circuit so that the leads are completely open. Hard break is dangerous to traditionally insulated LTS magnets, but the SS-insulated HTS DPC retained integrity over <inline-formula><tex-math notation="LaTeX">></tex-math></inline-formula>80 charge-discharge cycles. Voltage decay curves for soft and hard breaks are studied on short and long timescales. On long timescales, we observe the expected exponential decay and measure the time constant to calculate contact resistance. On short timescales, we observe highly dynamic effects: a hyper-exponential decay suggesting that the inductance or contact resistance is suddenly changing with time, likely an indication of the <inline-formula><tex-math notation="LaTeX">RL</tex-math></inline-formula> circuit forming. Moreover, peak voltage immediately (ms) after the sudden discharge were collected and compared. It is found that the peak voltage in soft-discharge is proportional to the applied current, while the those in hard-break has an unique pattern and tends to stay flat even though the applied current increases.
Inflammatory responses of nucleus pulposus (NP) can induce imbalanced anabolism and catabolism of extracellular matrix, and the cytosolic dsDNA accumulation and STING–NF–κB pathway activation found ...in NP inflammation are considered as fairly important cause of intervertebral disc (IVD) degeneration. Herein, we constructed a siSTING delivery hydrogel of aldehyde hyaluronic acid (HA-CHO) and poly(amidoamine) PAMAM/siRNA complex to intervene the abnormal STING signal for IVD degeneration treatment, where the formation of dynamic Schiff base bonds in the system (siSTING@HPgel) was able to overcome the shortcomings such as low cellular uptake, short half-life, and rapid degradation of siRNA-based strategy. PAMAM not only formed complexes with siRNA to promote siRNA transfection, but also served as dynamic crosslinker to construct hydrogel, and the injectable and self-healing hydrogel efficiently and steadily silenced STING expression in NP cells. Finally, the siSTING@HPgel significantly eased IVD inflammation and slowed IVD degeneration by prolonging STING knockdown in puncture-induced IVD degeneration rat model, revealing that STING pathway was a therapeutic target for IVD degeneration and such novel hydrogel had great potential for being applied to many other diseases for gene delivery.
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•STING-NF-κB pathway activation was identified an important cause of intervertebral disc degeneration.•PAMAM was employed as both linker and gene vector for siRNA delivery.•The injectable self-healing hydrogel could significantly ease the IVD inflammation and degeneration by prolonging STING knockdown.•This novel hydrogel system opened new ways of thinking and had great potential for gene delivery.
2G HTS Coil Technology Development at SuperPower Honghai Song; Brownsey, P.; Yifei Zhang ...
IEEE transactions on applied superconductivity,
06/2013, Letnik:
23, Številka:
3
Journal Article, Conference Proceeding
Recenzirano
The second-generation high-temperature superconductor (2G HTS), Re-Ba-Cu-O coated conductors are known for strong mechanical properties and have numerous potential applications in high magnetic field ...research and electrical power systems. It has been noted in the community that coated conductors can be prone to performance degradation on thermal cycling when used in epoxy impregnated magnet windings. This degradation has been tied to the c -axis peel strength in the wire. SuperPower is addressing this issue with a short term approach of developing novel technologies in conductor post processing and coil winding technology, which allows building high quality coils with current generation conductor, and a longer term approach of improving wire production to build stronger wire with high c -axis peel strength.
A 1-MW industrial-scale high-temperature superconductor (HTS) dc induction heater is being designed and manufactured in Shanghai Jiao Tong University, China. This paper is to present the design and ...engineering analysis of a HTS magnet with iron yoke for this heater. This magnet is to generate a 0.5-T dc magnetic field in the iron's air gap, where the billet is rotated. To enhance the thermal stability, the no-insulation (NI) coil and metallic insulation (MI) coil (co-wind with stainless steel strips) is introduced to the magnet. The influence of the NI&MI technique on the magnet's ramping process is analyzed. A significant ramping delay occurs on both the NI and MI magnet. Joules losses are generated by the current "bypassing" through turn-to-turn contacts, which may lead to significant temperature rise on the coils. Higher ramping rate often means faster ramping process and higher temperature rise induced by ramping loss. The MI magnet shows a much shorter ramping time and lower ramping loss than its NI counterpart, due to higher turn-to-turn resistivity. The MI coil is more suitable than the NI coil for this large-scale magnet.
This paper presents the design and test results of the pancake coils for the 25 T, 100 mm bore solenoid that Brookhaven National Laboratory (BNL) is building for the Institute for Basic Science (IBS) ...in Korea for an Axion dark matter search. The design is based on second-generation (2G) high-temperature superconducting (HTS) tape with no-insulation winding. The major challenges in the high-field, large aperture solenoid are the large stresses and the quench protection. Moreover, the design should be robust for reliable operation in a user facility environment. The paper will also present the construction and test results of two ~100 mm bore double pancake coils creating a peak field of up to ~17 T and similar hoop stresses as will be in the 25 T solenoid. The coils were subject to several severe tests, including the simulations of large defects and extended quench studies at ~4 K. The most striking part of these studies was the demonstration of how fast (a few hundred milliseconds) these coils can turn from the superconducting state to the normal state (quench or thermal runaway). This removes the past concerns of protecting high-field HTS coils because of the low quench propagation velocities.
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