Non-inductive plasma vertical position measurement for the 1056 s discharge on EAST.

Vertical position stability plays a crucial role in maintaining safe and reliable plasma operation for long-pulse fusion devices. In general, the vertical position is measured by using inductive magnetic coils installed inside the vacuum vessel; however, the integration drift effects are inherent for steady-state or long-pulse plasma operation. Developing a non-magnetic approach provides a fusion reactor-relevant steady-state solution that avoids the negative impact of integration drift. In this paper, we compare the non-inductively determined vertical position achieved by line-integrated interferometer and polarimeter measurements to that employing an inductive flux loop for a 1056 s discharge recently achieved on EAST (Experimental Advanced Superconducting Tokamak). Experimental results show that the non-inductive measurement is more robust than flux loops after 300 s if the integrator is not reset to suppress integrator drift. Real-time vertical position control using the non-inductive system is proposed for the next EAST experimental campaign.

Experimental Evidence of Intrinsic Current Generation by Turbulence in Stationary Tokamak Plasmas.

High-ß_{θe} (a ratio of the electron thermal pressure to the poloidal magnetic pressure) steady-state long-pulse plasmas with steep central electron temperature gradient are achieved in the Experimental Advanced Superconducting Tokamak. An intrinsic current is observed to be modulated by turbulence driven by the electron temperature gradient. This turbulent current is generated in the countercurrent direction and can reach a maximum ratio of 25% of the bootstrap current. Gyrokinetic simulations and experimental observations indicate that the turbulence is the electron temperature gradient mode (ETG). The dominant mechanism for the turbulent current generation is due to the divergence of ETG-driven residual flux of current. Good agreement has been found between experiments and theory for the critical value of the electron temperature gradient triggering ETG and for the level of the turbulent current. The maximum values of turbulent current and electron temperature gradient lead to the destabilization of an m/n=1/1 kink mode, which by counteraction reduces the turbulence level (m and n are the poloidal and toroidal mode number, respectively). These observations suggest that the self-regulation system including turbulence, turbulent current, and kink mode is a contributing mechanism for sustaining the steady-state long-pulse high-ß_{θe} regime.

[Clinical research of a continuous auscultation recorder based on artificial intelligence].

Objective: To investigate the feasibility and clinical significance of a continuous auscultation recorder of bowel sounds based on artificial intelligence in monitoring the bowel sounds. Methods: From November 1,2018 to August 12,2019, a continuous auscultation recorder of bowel sounds was applied to monitor the perioperative bowel sounds of 31 patients undergoing colorectal surgery, in order to discovery underlying rules which might be used to guide clinical practice. Results: After the operation, the bowel sounds continued to exist for (1.8±0.8) h, and then gradually weakened or disappeared, and recovered gradually after (11.2±3.5) h. The first exhaust and the first defecation were detected at the time of (22.7±5.8) h and (28.7±6.9) h after surgery, respectively. The bowel sounds rate increased after eating, and decreased significantly after exhaust/defecation. Conclusions: The continuous auscultation recorder of bowel sounds based on artificial intelligence was safe and effective, which can afford help to clinical evaluation.

Error correction associated with stray light for Faraday-effect polarimetry system on EAST.

The polarimeter-interferometer system with 11 double-pass radial-view measurement chords has the ability to provide electron density and plasma current profiles, making it exceptionally useful in daily operation on the Experiment Advanced Superconducting Tokamak. However, due to limited optical access and intrinsic feedback, the stray lights arising from spurious reflections along the optical path (unwanted reflections from various optical components/mounts and transmissive optical elements such as windows, waveplates, and lenses as well as the detectors) distort the Faraday rotation measurements. Furthermore, the feedback light from the retro-reflector which is used to realize the double-pass configuration makes it even worse. A data processing approach to decrease the stray light influence is reported in this paper. Based on the theoretical model developed, the Faraday rotation angle is extracted by subtracting the deviation term which can be calculated with a simplified model. With this approach, the Faraday rotation oscillation during density ramp-up can be reduced from 2°-5° to 0.5°-1.5°, which reduces the Faraday rotation measurement errors significantly.

Special configuration of a very large Schmidt telescope for extensive astronomical spectroscopic observation.

A special reflecting Schmidt telescope is used to observe celestial objects. The telescope has an aperture of 4m, f ratio of 5, and a 5° field of view. Its optical axis is fixed and tilted 25° to the horizontal that runs from south to north. The celestial objects were observed for 1.5 h as they passed through the meridian. The shape of the reflecting Schmidt plate has to be changed with each different declination δ and in the tracking process. This is achieved with active optics. The sky area to be observed is -10° ≤ δ ≤ +90°. There are plans to place ~4000 optical fibers on the telescope focal surface that will lead to a dozen spectrographs.

Altered mercaptopurine metabolism, toxic effects, and dosage requirement in a thiopurine methyltransferase-deficient child with acute lymphocytic leukemia.

Thiopurine methyltransferase deficiency, inherited as an autosomal codominant trait, is associated with aberrant mercaptopurine metabolism leading to excessive cellular accumulation of 6-thioguanine nucleotides, the active metabolites of mercaptopurine. We describe a case of severe thiopurine methyltransferase deficiency (activity less than 1 U/8 x 10(8) erythrocytes) in a young girl with acute lymphocytic leukemia. The level of 6-thioguanine nucleotide in the patient's erythrocytes was seven times the population median value, and she had intolerable hematologic toxic effects during postremission therapy with a standard dosage of mercaptopurine (75 mg/m2 per day). Subsequent therapy with 6% of this dosage (10 mg/m2 three times weekly) yielded erythrocytic 6-thioguanine nucleotide concentrations consistently above the population median but not associated with prohibitively toxic effects. This case demonstrates that thiopurine methyltransferase deficiency does not absolutely contraindicate mercaptopurine therapy, and it also provides insight into the mechanism of excessive toxic effects of mercaptopurine sometimes observed in children with acute lymphocytic leukemia.

Determination of the enantiomers of verapamil and norverapamil in serum using coupled achiral-chiral high-performance liquid chromatography.

An assay for the plasma concentration of the enantiomers of verapamil and its metabolite norverapamil has been developed using the improved version of the alpha 1-acid glycoprotein chiral stationary phase (CHIRAL AGP-CSP) coupled to a shielded hydrophobic phase (Hisep) column. The Hisep column was used to separate verapamil and norverapamil from the plasma components and from each other and to quantitate the total verapamil and norverapamil concentrations. The eluents containing verapamil and norverapamil are then selectively transferred to the CHIRAL AGP-CSP where the enantiomers were stereochemically resolved and the enantiomeric composition determined. The system is the first reported for the serum concentration of the enantiomers of verapamil after the clinical administration of the drug and the first to stereochemically resolve and quantitate the enantiomers of norverapamil.

The measurement of warfarin enantiomers in serum using coupled achiral/chiral, high-performance liquid chromatography (HPLC).

An assay for the serum concentration of the enantiomers of warfarin, R-warfarin and S-warfarin, has been developed using a bovine serum albumin chiral stationary phase (BSA-CSP) coupled to a Pinkerton internal-surface reverse-phase (ISRP) achiral column. The ISRP column is used to separate R,S-warfarin from the serum components and warfarin metabolites and to quantitate the total R,S-warfarin concentration. The eluent containing R,S-warfarin is then selectively transferred to the BSA-CSP, where the enantiomers are stereochemically resolved (alpha = 1.19) and the enantiomeric composition is determined. This system is sensitive and accurate, does not require extensive precolumn manipulations, and can be automated for use in large-scale clinical studies.