Development of solid state terahertz interferometer for the first plasma on HL-2M tokamak.

A solid state terahertz interferometer has been developed on the recent commissioned HL-2M tokamak. It can work in a wide frequency region of 220-325 GHz, and the terahertz wave is generated from a low frequency phase locked voltage controlled oscillator with the frequency multiplying technique. A phase processor based on field programmable gate array (FPGA) technology is designed for the heterodyne interferometer, and it contributes to real-time display of electron density. To extract phase information, a novel numerical algorithm related to fast Fourier transform is written on the FPGA chip and enables one to obtain phase shift without being affected by amplitude variation induced by plasma absorption or frequency modulation from the outer electromagnetic environment. The interferometer achieves minimum measurable electron density in the order of 1016 m-3. With the plasma diagnosis, electron density and low frequency tearing mode have been measured during the first experimental campaign.

[Analysis of risk factors for lymphoma patients dying of cardiovascular disease].

Objective: To understand and explore the risk factors of the death of lymphoma patients from cardiovascular disease. Methods: The medical records and death information of 1 173 patients with lymphoma were collected, cases that died from cardiovascular disease were screened. A binary logistic regression model was used to analyze the independent risk factors of patients with lymphoma died from cardiovascular disease. Results: Among 1 173 patients with lymphoma, 75 (6.4%) died of cardiovascular disease, including 27 cases of coronary heart disease, 25 cases of stroke, 7 cases of hypertension, 5 cases of sudden cardiac death, 4 cases of pulmonary embolism, 3 cases of heart failure, 4 cases of others. Among the patients who survived for more than 5 years, 16.1% (35/217) died of cardiovascular disease. Among those who survived for more than 10 years, 11.7% (7/60) died of cardiovascular disease. Multivariate Logistic regression analysis showed that the primary site of lymphoma (OR=0.521, P=0.039), stage (stage Ⅱ: OR=2.487, P=0.016; stage Ⅲ: OR=3.233, P=0.002) and cardiovascular toxicity in the course of diagnosis and treatment (OR=3.019, P=0.001) are independent influencing factors for the death of cardiovascular disease in patients with lymphoma. Patients whose primary sites of lymphoma were lymph nodes had lower risk of dying from cardiovascular disease, while the patients with stage Ⅱ to Ⅲ stage and cardiovascular toxicity during diagnosis and treatment had higher risk of dying from cardiovascular disease. Conclusions: Cardiovascular disease is an important factor affecting the survival of patients with lymphoma. With the extension of survival time, the risk of dying from cardiovascular disease increases significantly. The primary site, tumor stage, and cardiovascular toxicity that occur during the diagnosis and treatment may be the independent influencing factors for patients with lymphoma that die from cardiovascular disease.

[Analysis of the characteristics of second primary malignancy affecting the survival of lymphoma patients].

Objective: To analyze the characteristics of the second primary tumor affecting the survival of patients with lymphoma, and to explore the risk factors of death from the second primary tumor. Methods: The medical records and related death information of 1 173 lymphoma patients who had already died with known causes were collected. The basic causes of death and the characteristics of patients who died of the second primary tumor were analyzed. Cox regression model was used to analyze the risk factors of lymphoma patients who died of the second primary tumor. Results: Among the 1 173 patients who had died, 94 (8.0%) died of the second primary tumor, 935 (79.7%) died of the primary lymphoma and 144 (12.3%) died of other diseases. The second primary tumor accounted for 17.5% (38/217) of all causes of death in patients with the survival period of more than 5 years, and the second primary tumor accounted for 28.3% (17/60) of all causes of death in patients with the survival period of more than 10 years. Among 94 cases who died of second primary tumors, 31 died of lung cancer, 15 died of gastric cancer, 13 died of liver cancer, 9 died of pancreatic cancer, 6 died of colorectal cancer, 6 died of second primary lymphoma and 14 died of other types of tumors. Univariate Cox regression analysis showed that age, first-line treatment effect, and chest or mediastinal radiotherapy were associated with the death from second primary tumors for lymphoma patients (all P<0.05). Multivariate Cox regression analysis showed that the effect of first-line treatment (P=0.030) and the chest or mediastinal radiotherapy (P=0.039) were independent factors for the death of lymphoma patients from the second primary tumor. Conclusions: The second primary tumor is an important factor affecting the survival of lymphoma patients, and the risk of death from second primary tumors increases significantly over time. The effect of first-line treatment and radiotherapy in the chest or mediastinum are independent factors for the death of lymphoma patients from the second primary tumor.

[The health status of radiation workers and the analysis of crystalline lens results].

Objective: To understand the healthy status of radiation workers on the staff in Nanjing, and to analysis the relationship between abnormal crystalline lens and its influencing factors. Methods: We described physical indicators including blood pressure (BP) 、blood sugar (BG) 、thyroid B ultrasound、crystalline lens、chromosome and so on among 3 349 radiation workers on the staff in the year 2016 from Jan 1 to Dec 31, and the abnormal results of crystalline lens were analyzed statistically. Results: The rate of abnormal BP、BG、WBC、Thyroid B ultrasound、crystalline lens was 19.0%、2.2%、5.8%、30.0%、3.6% respectively; The rate of chromosome aberration was 0.1%, and the chromosomal micronuclei are all within normal range. With the rate of abnormal crystalline lens increasing in age and working years, statistical significance both existed in the trend; Compared to the lowest group, the risk of abnormal crystalline lens increased 3.86 times in ≥60 year old group and 3.16 times in ≥30 years working group; The risk of abnormal crystalline lens in nosocomial radation group was higher than non-medical group; There's no found in smoking and drinking alcohol increasing the risk. Morphologically, dot abnormal focused on 30~39 years old and 0~9 working years group, while lamellar abnormal concentrated upon ≥60 year old、≥30 working years group; Age and working-year were both the risk factors of lamellar abnormal; The risk of lamellar abnormal in nosocomial radiation group was significantly higher than non-medical group. Conclusion: Existing nisk foctions in the radiation work has a serious impact on several healthy physiology indicators, the more prominent was crystalline lens. Attention should be paid to eye protection and comprehensive health management.

[To investigate the correlation of nasal secretions of eosinophils and lung function after the treatment of budesonide in the allergic rhinitis patients].

Objective:To identify the relationship between nasal secretion eosinophilia and pulmonary function of patients with AR after treatment of intranasal budesonide.Method:Fifty patients with moderate to severe AR were selected, and compared to 50 normals, all had pulmonary function and nasal secretion of eosinophil number check, experimental group of AR received budesonide+loratadine treatment for 3 months, and then had lung function and nasal secretion eosinophil again, analysised the trends of change between two. Result:Eosinophils of AR patients was higher than its of control group (P<0.05), lung function index MMEF and nasal secretion eosinophilia of 50 AR patients had a negative relationship(r=-0.945，P<0.05).Treated with eosinophils the number of nasal secretion eosinophilia of AR decreased 10 + 5.6, the difference compared to the before of the treatment was statistically significant(P<0.05), compared to the normal control group was significant(P<0.05). After the treatment of budesonide, the trends of change between nasal secretion eosinophils and pulmonary function was a positive correlation(r=0.803,P<0.01). Conclusion:The higher the number of eosinophils in nasal secretions of patients with AR, the more obvious the decline of lung function. After the treatment with budesonide, the more eosinophils decreased in patients with AR, the more obvious the improvement of pulmonary function.

Synchronization of Geodesic Acoustic Modes and Magnetic Fluctuations in Toroidal Plasmas.

The synchronization of geodesic acoustic modes (GAMs) and magnetic fluctuations is identified in the edge plasmas of the HL-2A tokamak. Mesoscale electric fluctuations (MSEFs) having components of a dominant GAM, and m/n=6/2 potential fluctuations are found at the same frequency as that of the magnetic fluctuations of m/n=6/2 (m and n are poloidal and toroidal mode numbers, respectively). The temporal evolutions of the MSEFs and the magnetic fluctuations clearly show the frequency entrainment and the phase lock between the GAM and the m/n=6/2 magnetic fluctuations. The results indicate that GAMs and magnetic fluctuations can transfer energy through nonlinear synchronization. Such nonlinear synchronization may also contribute to low-frequency zonal flow formation, reduction of turbulence level, and thus confinement regime transitions.

On the interplay between neoclassical tearing modes and nonlocal transport in toroidal plasmas.

This Letter presents the first observation on the interplay between nonlocal transport and neoclassical tearing modes (NTMs) during transient nonlocal heat transport events in the HL-2A tokamak. The nonlocality is triggered by edge cooling and large-scale, inward propagating avalanches. These lead to a locally enhanced pressure gradient at the q = 3/2 (or 2/1) rational surface and hence the onset of the NTM in relatively low ß plasmas (ßN < 1). The NTM, in return, regulates the nonlocal transport by truncation of avalanches by local sheared toroidal flows which develop near the magnetic island. These findings have direct implications for understanding the dynamic interaction between turbulence and large-scale mode structures in fusion plasmas.

Observation of Double Impurity Critical Gradients for Electromagnetic Turbulence Excitation in Tokamak Plasmas.

The impact of impurity ions on a pedestal has been investigated in the HL-2A Tokamak, at the Southwestern Institute of Physics, Chengdu, China. Experimental results have clearly shown that during the H-mode phase, an electromagnetic turbulence was excited in the edge plasma region, where the impurity ions exhibited a peaked profile. It has been found that double impurity critical gradients are responsible for triggering the turbulence. Strong stiffness of the impurity profile has been observed during cyclic transitions between the I-phase and H-mode regime. The results suggest that the underlying physics of the self-regulated edge impurity profile offers the possibility for an active control of the pedestal dynamics via pedestal turbulence.

Development of the radial neutron camera system for the HL-2A tokamak.

A new radial neutron camera system has been developed and operated recently in the HL-2A tokamak to measure the spatial and time resolved 2.5 MeV D-D fusion neutron, enhancing the understanding of the energetic-ion physics. The camera mainly consists of a multichannel collimator, liquid-scintillation detectors, shielding systems, and a data acquisition system. Measurements of the D-D fusion neutrons using the camera have been successfully performed during the 2015 HL-2A experiment campaign. The measurements show that the distribution of the fusion neutrons in the HL-2A plasma has a peaked profile, suggesting that the neutral beam injection beam ions in the plasma have a peaked distribution. It also suggests that the neutrons are primarily produced from beam-target reactions in the plasma core region. The measurement results from the neutron camera are well consistent with the results of both a standard (235)U fission chamber and NUBEAM neutron calculations. In this paper, the new radial neutron camera system on HL-2A and the first experimental results are described.

[Effects of nasal steroids on pulmonary function in patients with allergic rhinitis].

Objective:The aim of this study was to observe the changes of pulmonary function in patients with allergic rhinitis and the effect of nasal glucocorticoid on pulmonary function.Method:Ninety patients with Moderate and severe AR and 50 healthy control subjects were recruited.All participates accepted a pulmonary function test and make a statistical analysis.90 patients of AR were divided into two groups:A group(50) and B group(40).A group treated with nasal budesonide and loratadine,while B group treated with nasal normal saline and loratadine.After 3 months,all patients reviewed the lung function.Result:Comparing with control,FEV1.0/FVC,MMEF,FEF50% and FEF75% reduced significantly in AR group(P<0.01),after 3 months,the treatment of A group compared before:FEV1.0/FVC(P<0.05),MMEF,FEF50% and FEF75%(P<0.01) had statistical significance.Compared B group after the treatment:FEF75% (P<0.05) was significant.After the treatment of group A compared with normal group:there was no significance.Conclusion:The reduced pulmonary function of allergic rhinitis paitents is mainly due to the small airway dysfunction.Budesonide is superior to loratadine to improve the pulmonary function.

Diagnostics for energetic particle studies on the HL-2A tokamak.

About 13 kinds of diagnostics for energetic particle physics studied on the HuanLiuqi-2A (commonly referred to as HL-2A) tokamak are described in this paper. Their measurement ranges, resolutions, and arrangement are presented. Three under-construction diagnostics including imaging fast ion D-alpha, scintillator matrix (for hard X-ray detection), and bundle fission chamber are described in detail.

The motional Stark effect polarimeter in the HL-2A tokamak.

A 7-channel motional Stark effect polarimeter based on four polarizers and a spectrometer has been developed in the HL-2A tokamak, which is the first time successful utilizing this kind of polarimeter on a tokamak. The accuracy of the angle can reach ±0.25° in the calibration experiments. Pilot experiments of measuring the magnetic pitch angle have been successfully carried out in the weak motional Stark effect plasma discharge with toroidal magnetic field of ~1.3 T and beam energy of ~25 keV/amu. The pitch angles of magnetic field are obtained for 7 spatial points covering 24 cm along major radius with time resolution of 40 ms; the profiles of safety factor are obtained by combining with the Equilibrium and Reconstruction Fitting Code. The core value of safety factor (q) is less than 1 during the sawtooth oscillation and the position of q = 1 surface is well consistent with the results measured by soft X-ray array.

Diamagnetic measurements by concentric loops in the HL-2A tokamak.

The diamagnetic concentric loop method in the HL-2A tokamak is described in this article. The system consists of two concentric poloidal loops with different areas enclosing the plasma column and a short time constant differential integrator, RC < 1 ms. The diamagnetic flux in HL-2A ranges from 1 mWb to 2 mWb for typical discharges with plasma current Ip = 100-400 kA. The integrator output ranges from 0.1 V to 0.2 V with time constant RC = 0.5 ms, and differential area ΔS∕Sout ≈ 7%. Using hybrid analog-digital compensation, the integration drift can be well compensated within 5 mV∕10 s, which can meet the requirement of the concentric loop system. In this method, the measurement of differential area ΔS is not required. The vacuum toroidal flux can be compensated by adjusting the resistance in the integration circuit for several discharges with toroidal field only, which minimizes the additional error produced by a measurement of differential area. The diamagnetic concentric loop system improved the signal to noise ratio by using the short time constant integration. The system with a resolution of ±0.2 kJ can be used to study rapid changes in plasma stored energy, such as the additional power absorbed by the plasma, and the energy loss caused by edge localized modes.

Dynamics of low-intermediate-high-confinement transitions in toroidal plasmas.

The dynamic features of the low-intermediate-high-(L-I-H) confinement transitions on HL-2A tokamak are presented. Here we report the discovery of two types of limit cycles (dubbed type-Y and type-J), which show opposite temporal ordering between the radial electric field and turbulence intensity. In type-Y, which appears first after an L-I transition, the turbulence grows first, followed by the localized electric field. In contrast, the electric field leads type-J. The turbulence-induced zonal flow and pressure-gradient-induced drift play essential roles in the two types of limit cycles, respectively. The condition of transition between types-Y and -J is studied in terms of the normalized radial electric field. An I-H transition is demonstrated to occur only from type-J.

Apoptosis of peripheral T cells in rodent cardiac allograft recipients induced by donor-specific transfusion with impaired inducible costimulator/B7 homologous protein allorecognition.

OBJECTIVE: To investigate apoptosis of the CD8(+) T cells (Tc) subpopulation in rodent cardiac allograft recipients, which were treated by donor specific transfusion combined with blockade of Inducible costimulator (ICOS)/B7 homologous protein (B7h) costimulation. METHODS: Donor hearts were heterotopically transplanted into the necks of recipient mice using Chen's technique. Postoperative graft survival was recorded. Both the percentage of CD3(+)CD8(+)ICOS(+) Tc in recipients' peripheral blood and the apoptosis of CD8(+) Tc in recipient draining lymph nodes were detected by flow cytometry analysis. RESULTS: In comparison with the allogeneic group, the survival of cardiac grafts was prolonged by combined treatment with 5 × 10(6) ICOS-Fc-targeted B cells on day 0 of transplantation and 10 mg/kg/d ICOS-Fc on days 0 to 6 (84.38 ± 29.14 days versus 7.00 ± 0.76 days, P < .01). The treatment group showed a stable CD8(+)Tc clone size in recipient peripheral blood (49.4% ± 3.11% versus 50.0% ± 2.46%, P > .05); however, the percentage of CD3(+)CD8(+)ICOS(+) Tc decreased significantly compared with the allogeneic group (7.5% ± 2.02% versus 14.0% ± 3.03%, P < .05). Compared with allogeneic group, apoptosis of the CD8(+) Tc subpopulation in recipient draining lymph nodes was up-regulated significantly at postoperative 7 days in the treatment group (19.53% ± 5.10% versus 8.70 ± 3.14%, P < .05). CONCLUSION: Apoptosis of CD8(+) Tc in recipient draining lymph nodes was enhanced by pretreatment with donor specific transfusion and impaired ICOS/B7h allorecognition, which may have been associated with the variation in the CD3(+)CD8(+)ICOS(+) Tc subpopulation in peripheral blood and at least partially contributed to unresponsiveness toward cardiac allograft.

Inhibition of T-cell expansion caused by inducible costimulator/B7h costimulation blockade in direct allorecognition pathway.

OBJECTIVE: Inducible costimulator (ICOS)/B7h costimulation plays a crucial role in acute and chronic allograft rejection. To test the role of the ICOS signal in T-cell activation and expansion, we used ICOS-Fc-targeted B cells as donor antigen presenting cells to challenge the allogeneic response in vitro. METHODS: In vitro, the binding of ICOS-Fc with B7h on splenic B cells was confirmed by flow cytometry analysis. To evaluate the capacity of ICOS-Fc-targeted B cells to elicit an allogeneic response in vitro, we performed mixed lymphocyte reactions. RESULTS: The binding of B7h on splenic B cells by ICOS-Fc was confirmed at a saturating concentration of 100 µg/mL. Blockade of ICOS/B7h in direct allorecognition depressed proliferation of alloreactive T cells in vitro. CONCLUSIONS: ICOS/B7h signal plays an important role in direct allorecognition, eliciting allogeneic responses in vitro.

Time-frequency analysis for microwave reflectometry data processing in the HL-2A tokamak.

The Choi-Williams distribution (CWD) technique is introduced as a time-frequency tool for processing data measured from the new developed homodyne and the fixed frequency reflectometry in the HL-2A tokamak. The comparison between spectrogram and CWD for the simulated signal is presented. It indicates that the CWD can greatly improve the representation of the time-frequency content of the multi-components signal. Its effectiveness is demonstrated through two applications in HL-2A, which are the extraction of beat frequencies from the frequency modulated-continuous wave reflectometry (FM-CW) and the characterizing of the fluctuations. The density profile inversed from the group delay of the FM-CW and the density fluctuations deduced from the fixed-frequency reflectometry would be more reliable and accurate by using the CWD technique.

Measurements of the fast electron bremsstrahlung emission during electron cyclotron resonance heating in the HL-2A tokamak.

A fast electron bremsstrahlung (FEB) diagnostic technique based on cadmium telluride (CdTe) detector has been developed recently in the HL-2A tokamak for measurements of the temporal evolution of FEB emission in the energy range of 10-200 keV. With a perpendicular viewing into the plasma on the equatorial plane, the hard x-ray spectra with eight different energy channels are measured. The discrimination of the spectra is implemented by an accurate spectrometry. The system also makes use of fast digitization and software signal processing technology. An ambient environment of neutrons, gammas, and magnetic disturbance requires careful shielding. During electron cyclotron resonance heating, the generation of fast electrons and the oscillations of electron fishbone (e-fishbone) have been found. Using the FEB measurement system, it has been experimentally identified that the mode strongly correlates with the electron cyclotron resonance heating produced fast electrons with 30-70 keV.

Observation of a spontaneous particle-transport barrier in the HL-2A tokamak.

Using the profile analysis, the density perturbation transport analysis, and the Doppler reflectometry measurement, for the first time a spontaneous and steady-state particle-transport barrier has been evidenced in the Ohmic plasmas in the HL-2A tokamak with no externally applied momentum or particle input except the gas puffing. A threshold in density has been found for the observation of the barrier. The particle diffusivity is well-like, and the convection is found to be inward outside the well and outward inside the well. The formation of the barrier coincides with the transition between the trapped electron mode and the ion temperature gradient driven mode.