Development of a real-time impedance matching system for ion cyclotron resonance heating in experimental advanced superconducting tokamak.

To achieve stable operation of an ion cyclotron resonance heating (ICRH) system in the Experimental Advanced Superconducting Tokamak (EAST), a real-time impedance matching system needs to be established to respond to antenna load variation during long pulse discharges. A new impedance matching method based on capacitors was proposed in this study. By considering the reflected voltage of the transmission line as the feedback parameter, the real-time impedance-matching system can quickly control the motors based on a programmable logic controller to determine the minimum reflection voltage. A real-time impedance matching system was successfully used on the test platform in the laboratory and on the ICRH system in EAST. A significant result is that we can match the variable impedance within 1 s by suitably adjusting the motor controller to ensure high-power and long-pulse operation of the ICRH system to satisfy the requirements of the EAST experiment.

Design and analysis of radio frequency window for the China Fusion Engineering Test Reactor ion cyclotron range of frequency heating system.

The Ion Cyclotron Range of Frequency (ICRF) heating system of the China Fusion Engineering Test Reactor (CFETR) is intended to provide plasma heating with a minimum power output of 20 MW, which demands the Radio Frequency (RF) window to possess a higher performance requirement. This paper presents the design of an RF window for the CFETR ICRF heating system and focuses primarily on the design and confirmation of its electromagnetic performance. The RF window can be effectively matched in the operating frequency range and has an S11 of under -59 dB. The geometry of the cone type ceramics was optimized to reduce the surface tangential electric field distribution. An analysis of the electric field distribution of the RF window at 50 kV indicates that the pressure side was below 2.3 kV/mm and the vacuum side was below 1.3 kV/mm. Furthermore, a transmission line test bench with an open-terminated setup was constructed to conduct withstand voltage tests on the mockup, and the results showed that the mockup could withstand 62 kV for 2 s and 47 kV for 120 s.

[Comparison of the efficacy of irreversible electroporation and conversional resection for locally advanced pancreatic cancer].

Objective: To compare the short-term and long-term prognosis of irreversible electroporation(IRE) and conversional resection for locally advanced pancreatic cancer(LAPC). Methods: The clinical and pathological data of 98 LAPC patients who underwent IRE or conversional resection at the Department of Pancreatobiliary Surgery,Sun Yat-sen University Cancer Center from August 2015 to December 2020 were retrospectively collected and analyzed.The study comprised of 53 males and 45 females, with age(M(IQR)) of 57.5(13.5)years old(range:20 to 87 years old). Fifty-three patients received IRE treatment(IRE group) and 45 patients received surgical resection(resection group). The differences of clinical and pathological data between both groups were not significant(all P<0.05). The Mann-Whitney U test was used for quantitative data and the χ2 test was used for categorical data.Survival was analyzed using Kaplan-Meier method and compared using Log-rank test. Results: The operation time and intraoperative blood loss were 5.0(2.4)hours and 50(100) ml in the IRE group,respectively,which were significantly less than those of resection group(7.0(3.3)hours and 400(200)ml,both P<0.05).The hospital stay and hospitalization cost were 9.0(3.0)days and 79 154 (83 738) yuan in the IRE group,respectively,which were also significantly less than those in the resection group(16.0(8.5)days and 109 557(37 795)yuan,both P<0.05).The complication rate of IRE group was significantly lower than that of the resection group(18.8% vs. 55.6%,χ2=14.270,P<0.01).The median overall survival(OS) time of IRE group was 28.9 months(95%CI:23.2 to 34.6 months),with the 1-,2-,and 3-year OS rates of 91.6%,61.7%,and 24.6%,respectively.The median survival of OS of resection group was 27.1 months(95%CI:20.9 to 33.3 months),with the 1-,2-,and 3-year OS rates of 81.8%,53.9%,and 30.3%,respectively.There was no significant difference in OS between the two groups(χ2=0.900,P=0.760).The median progression free survival(PFS) time of IRE group was 18.0 months(95%CI:14.7 to 21.3 months),with the 1-,2-,and 3-year PFS rates of 68.3%,29.7%,and 9.9%,respectively.The median survival of PFS of resection group was 11.1 months(95%CI:6.1 to 16.2 months),with the 1-,2-,and 3-year PFS rates of 45.2%,21.9%,and 14.6%,respectively.There was no significant difference in PFS between the two groups(χ2=1.850,P=0.170). Conclusion: IRE can achieve similar survival for LAPC and may has less complications compared to those with conversion resection.

Impedance matching system using triple liquid stub tuners for high-power ion cyclotron resonance heating in EAST tokamak.

Ion cyclotron resonance heating (ICRH), one of the main auxiliary methods, for high-power and long-pulse plasma heating had been developed in Experimental Advanced Superconducting Tokamak (EAST). An impedance matching system, one important part of ICRH, had been developed for high-power injection and transmitter protection by reducing the reflected power from the antenna. The input impedance in the outlet of the stub tuner can be measured by voltage-current probes installed on the coaxial transmission line between the antenna and triple liquid stub tuners, and the optimum liquid levels in the stub tuners can be calculated based on the input impedance. The calculation and adjustment process of the optimum liquid levels are described comprehensively in this article. Finally, impedance matching had been achieved between two shots during EAST experiments. In the near future, a real-time impedance matching system will be developed to prevent large variations of the ICRH antenna impedance and achieve steady-state and long-pulse operation with the ICRH system.

[Combining intraoperative ultrasound-guided irreversible electroporation with chemotherapy for treating locally advanced pancreatic cancer: a clinical report of 64 cases].

Objective: To examine the safety and clinical efficacy of ultrasound-guided irreversible electroporation (IRE) using the open surgery approach, after induction chemotherapy, in the treatment of locally advanced pancreatic cancer (LAPC) . Methods: The data of 64 LAPC patients who underwent ultrasound-guided IRE using the open surgery approach after induction chemotherapy at Department of Pancreatobiliary Surgery, Sun Yat-sen University Cancer Center from August 2015 to March 2019 were retrospectively analyzed. The study comprised of 30 males and 34 females, with median age of 58.5 years old (range: 34 to 87 years old) , were included in this study.The tumor was located in the pancreatic head and body/tail in 30 and 34 patients, respectively.The largest recorded tumor size was 6.1 cm (≤4.0 cm: n=35; >4.0 cm: n=29) .To create an electric field around the tumor, Two to six probes were parallelly inserted into each patient's tumor, based on the size of the tumor, at a distance of 2 cm apart through the transverse mesocolon in a caudal-to-cranial direction.According to the numerical sequence of patients undergoing ultrasound-guided IRE, the first 15 cases and following 49 patients were categorized as the primary and secondary treatment group, respectively.T text or χ(2) test was analyzed to the data between two groups.The study endpoints were overall survival (OS) and progression free survival (PFS) , which were investigated using Kaplan-Meier method, and their differences were compared using log-rank test. Results: The overall length of hospital stay was (8.9±2.7) days (range: 5 to 20 days) . Four patients were lost to follow-up.The study follow-up rate was 93.8%, with a median follow-up time of 29.3 months (range: 13.5 to 55.7 months) .The median OS and PFS of the entire cohort was 24.6 months (95% CI: 22.0 to 27.3 months) and 12.0 months (95%CI: 8.8 to 15.2 months) , respectively.One month after IRE, abdominal pain was significantly relieved in 95.3% of the patients (t=-28.55, P<0.01) .The rate of complications in the entire cohort was 20.3% and all were classified as grade B.Of them, pancreatic fistula, incisional infection, and upper gastrointestinal hemorrhage were observed in 7, 4, and 2 cases, respectively.The rate of complications for patients in the primary and secondary treatment groups were significantly different (10/15 vs. 6.1%) , respectively (χ(2)=26.01, P<0.01) .Further, two deaths were observed after IRE in the primary treatment group, while none was observed in the secondary treatment group. Conclusions: Ultrasound-guided IRE using the open surgery approach after induction chemotherapy is found to be safe and effective in treating patients with LAPC.However, these findings should be validated in prospective randomized trials before wide clinical application.

Ion cyclotron emission diagnostic system on the experimental advanced superconducting tokamak and first detection of energetic-particle-driven radiation.

A passive and noninvasive diagnostic system based on high-frequency B-dot probes (HFBs) has been designed and developed for the measurement and identification of ion cyclotron emission (ICE) in the Experimental Advanced Superconducting Tokamak (EAST). Details of the hardware components of this system including HFBs, direct current blockers, radio frequency splitters, filters, and power detectors as well as data acquisition systems are presented. A spectrum analyzer is used in addition to the ordinary speed acquisition card for data registration and analysis. The reliability of a HFB based diagnostic system has been well validated during the 2018 spring experiments on the EAST. ICE signals corresponding to fundamental cyclotron frequency of hydrogen ions and harmonics of deuterium ions were observed in experiments where deuterium plasmas were heated with deuterium neutral beams. The field dependence of ICE has been verified by recent experiments with three different background magnetic fields. The observed ratio of the ICE frequency is consistent with the ratio of the magnetic field intensity within measurement errors of a few percent.

Construction of three different recombinant scorpion fusion proteins with bifunctional activity.

This is the first report of three different fusion proteins with an antitumor-analgesic peptide obtained from Chinese scorpion Buthus martensii Karsch (BmKAGAP). The fusion proteins were constructed in the form of chimeric toxins, aiming to obtain bifunctional analgesic and antitumor activity. The fusion proteins consisted of luteinizing hormone-releasing hormone (LHRH), three different types of flexible linkers (L1, Ser-Ser-His-His-His-His-His-His-Ser-Ser-Gly-Leu-Val-Pro-Arg-Gly-Ser-His-Met; L2, Gly-Gly-Gly-Ser-Gly-Gly-Gly-Ser; L3, Ser-Gly-Gly-Ser-Gly-Gly-Ser-Gly-Gly-Gly-Ser-Ser-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Ser), and BmKAGAP. The genes coding three fusion proteins were cloned and expressed in E. coli in soluble form. Following two successive column chromatographic separations, purified fusion proteins were obtained. These fusion proteins exhibited analgesic activity in mice and were cytotoxic to a hepatocellular carcinoma cell line Hep3B.

Oxidative reactivity of S-nitrosoglutathione with Hantzsch 1,4-dihydropyridine.

[formula: see text] S-Nitrosoglutathione oxidized 4-substituted Hantzsch 1,4-dihydropyridines in CH3CN/H2O or CH3CN/phosphate aqueous buffer solution to give aromatic products in various yields.