Application of random sample consensus method for parameter estimation of reflectometry density profile in toroidal plasma.

Microwave reflectometry diagnostics have been widely used to measure density profiles in fusion plasma. However, the high sensitivity of the diagnostics to plasma turbulence often results in large radial deviations in the edge density profile and causes difficulty in profile evaluation. To improve the performance of profile evaluation, a modified RANdom SAmple Consensus (RANSAC) method has been applied to fit the density profiles measured by reflectometry on the experimental advanced superconducting tokamak. Compared with the traditional least-squares method, the modified RANSAC method is much more efficient and robust in fitting the experimental profiles. Furthermore, a combination of RANSAC and a genetic algorithm (GA-RANSAC) is used to further optimize the profile evaluation procedure. The results show that this GA-RANSAC method yields better performance and stabler convergence than the modified RANSAC alone.

Nucleation and Growth Bottleneck in the Conductivity Recovery Dynamics of Nickelate Ultrathin Films.

We investigate THz conductivity dynamics in NdNiO3 and EuNiO3 ultrathin films (15 unit cells, u.c., ∼5.7 nm thick) following a photoinduced thermal quench into the metallic state and reveal a clear contrast between first- and second-order dynamics. While in EuNiO3 the conductivity recovers exponentially, in NdNiO3 the recovery is nonexponential and slower than a simple thermal model. Crucially, it is consistent with first-order dynamics and well-described by a 2d Avrami model, with supercooling leading to metastable phase coexistence on the nano- to mesoscopic scale. This novel observation is a fundamentally dynamic manifestation of the first-order character of the insulator-to-metal transition, which the nanoscale thickness of our films and their fast cooling rate enable us to detect. The large transients seen in our films are promising for fast electronic (and magnetic) switching applications.

[Evaluation of peer support education mode for type 2 diabetes control in rural residents].

Objective: To evaluate the intervention effects of peer support education mode for type 2 diabetes control in rural residents. Methods: A random cluster sampling method has been used, including 300 rural residents aged above 18 years old from three villages (184 in control group, 116 in intervention group), in order to proceed the physical check-up and health education programs. Unchanged rate, transfer rate of patients, rate of impaired glucose tolerance, turn normal rate and other biochemical indicators of patients and people with impaired glucose tolerance from control group and intervention group were analyzed, to evaluate the intervention effects of peer support education mode. Results: The glycemic control rate of intervention group for patients and people with impaired glucose tolerance (72.2% and 71.4%) were higher than control group (43.6% and 26.7%), but the unchanged rate of intervention group (13.9% and 0.0%) were lower than control group (42.3% and 73.3%). Patients with diabetes or glucose intolerance in the education group improved significantly in waist-to-hip ratio, uric acid, total cholesterol and HDL-C. Glycemic hemoglobin level also improved significantly in diabetes patients of the education group. Conclusion: Peer support for education intervention seemed beneficial for diabetic control. The combination of education and effect evaluation was important in the evaluation of diabetes prevention and control. Peer support education also benefited the blood glucose control in general population.

Development of an ordinary mode multi-channel correlation reflectometer on EAST tokamak.

An ordinary-mode polarized multi-channel correlation reflectometer has been developed on the Experimental Advanced Superconducting Tokamak (EAST). The system with four different probing frequencies (i.e., 20.4 GHz, 24.8 GHz, 33 GHz, and 40 GHz) and two poloidally spaced receiving antennas can realize both the radial correlation measurement and the poloidal correlation measurement. These diagnostics focus on the measurement of density fluctuation in the pedestal region to investigate the turbulence transport and H-mode physics on EAST. In this article, the system hardware design, the key component tests, and the system performance are shown in detail.

Multi-channel poloidal correlation reflectometry on experimental advanced superconducting tokamak.

A new multi-channel poloidal correlation reflectometry is developed at Experimental Advanced Superconducting Tokamak. Eight dielectric resonator oscillators with frequencies of 12.5 GHz, 13.5 GHz, 14.5 GHz, 15 GHz, 15.5 GHz, 16 GHz, 17 GHz, and 18 GHz are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together. The output waves are launched by one single antenna after passing through a 20 dB directional coupler which can provide the reference signal. Two poloidally separated antennae are installed to receive the reflected waves from plasma. The reference and reflected signals are down-converted by mixing with a quadrupled signal from a phase-locked source with a frequency of 14.2 GHz and the IF signals pass through the filter bank. The resulting signals from the mixers are detected by I/Q demodulators. The setup enables the measurement of density fluctuation at 8 (radial) × 2 (poloidal) spatial points. A coherent mode with an increasing velocity from 50 kHz to 100 kHz is observed by using the system. The mode is located in the steep gradient region of the pedestal.

Characterization and in vitro cellular uptake of PEG coated iron oxide nanoparticles as MRI contrast agent.

Monodisperse magnetic iron oxide nanoparticles (MNPs), coated with PEG at different molecular weight, were prepared via self-assembly method. The particle diameters were measured by dynamic light scattering and transmission electron microscope. Increasing the molecular weight of PEG in the coating polymer increased the overall particles diameter. As coating thickness increased, the saturation magnetization (Ms) and T2 relaxivity decreased. The interactions of these MNPs with macrophage cells were also investigated. The results showed that cellular uptakes of MNPs depended on nanoparticle concentration and surface chemistry. The results of this study will have implications on the chemical design of nanomaterials for bio-imaging and bio-detection.

Induction of lactoferrin expression in murine ES cells by retinoic acid and estrogen.

Lactoferrin is an iron-binding glycoprotein present in high concentrations in milk and exocrine fluids such as bile and tears. Many functions have been attributed to lactoferrin, including antimicrobial and antiviral activities, immunomodulation, and cell growth regulation. Lactoferrin expression is controlled by different regulators, including retinoic acid and estrogen. However, the expression pattern of lactoferrin in mammalian early development has not yet been reported. Murine embryonic stem cells are pluripotent cells that can contribute to all tissues and were used for this study. We show here that while no lactoferrin protein or mRNA was detected in untreated murine embryonic stem cells, retinoic acid and estrogen can induce high levels lactoferrin expression in these cells. Expression, demonstrated by reverse transcription-polymerase chain reaction, Western blot, immunofluorescence, and ELISA assay, was dose and time dependent. Our study provides an in vitro model for examining lactoferrin expression in early development and differentiation.