Exploration of gastric carcinogenesis from the relationship between bile acids and intestinal metaplasia and intragastric microorganisms (H. pylori and non-H. pylori).

Gastric cancer (GC) is a prevalent form of cancer, with Helicobacter pylori (H. pylori) infection being the most common risk factor. Recent studies have highlighted the role of long-term irritation of the gastric mucosa caused by bile reflux in the development of cancer. Bile acids (BAs), which are a significant component in bile reflux, have the potential to promote gastric carcinogenesis through various mechanisms. These mechanisms include the induction of intestinal metaplasia (IM), inhibition of H. pylori activity, modification of H. pylori colonization, and alteration of the abundance and composition of microorganisms in the stomach. Defining the mechanism of bile acid-induced gastric carcinogenesis could potentially be an effective approach to prevent GC. Hence, this paper aims to review the mechanism of bile acid-induced IM, the association between BAs and H. pylori infection as well as microorganisms in the stomach, and the correlation between BAs and gastric carcinogenesis. The ultimate goal is to elucidate the role of BAs in the development of GC.

Causal associations between serum amino acid levels and osteoarthritis: a Mendelian randomization study.

OBJECTIVE: The association between serum amino acid (AA) levels and osteoarthritis (OA) risk remains unclear. METHOD: We performed a two-sample Mendelian randomization (MR) analysis to analyze the causal effects of serum AA levels on the OA risk by using summary-level genome-wide association study (GWAS) data. Inverse variance weighted (IVW) and Wald ratio were used as the main analysis. We also applied MR-Egger, Weighted median and Robust Adjusted Profile Score (MR.RAPS) methods. Heterogeneity and horizontally pleiotropic outliers were checked. The causal effects of AAs on early-onset all OA were explored. We also performed multivariable MR (MVMR) and conducted the bidirectional MR. RESULTS: The results suggested that genetically predicted alanine (Ala), tyrosine (Tyr) and isoleucine (Ile) levels were significantly associated with OA risk [e.g., association between Ala and hip/knee OA risk: OR = 0.82, 95% confidence interval (CI) = 0.75-0.90, P = 1.54E-05]. The study yielded little evidence of associations between genetically predicted AA levels with early-onset all OA risk. When adjusting the body mass index (BMI) in the MVMR model, suggestive causal effects of Ala and Tyr were also identified, while the effects of Ile substantially attenuated with OA risk. No significant associations between OA and AA levels were observed after testing for bidirectionality. CONCLUSIONS: Some AAs, such as Ala, Tyr and Ile likely affects the OA risk especially at hip or knee joints. The findings highlight the important role that serum AAs might play in the development of OA and provided new treatment approaches to OA.

[Effect evaluation of "Smoking cessation: Doctor first"program in China].

Objective: To evaluate the effect of "Smoking cessation: Doctor first" program on smoking medical staff. Methods: From December 2016 to September 2019, 1 747 smoking medical staff from 54 units of China Tobacco Cessation Alliance were enrolled into"Smoking cessation: Doctor first"program. Demographic characteristics, smoking characteristics, degree of tobacco dependence, willingness to quit smoking and other related factors were collected during the baseline survey. Multivariate logistic regression model was used to analyze the related factors of willingness to quit. The subjects were given intensive smoking cessation intervention from October 2017 to September 2019, including education on the hazards of smoking, methods of smoking cessation and giving smoking cessation drugs. After intervention, the subjects were investigated about their smoking cessation progress and the effect of the project was evaluated. Results: The subjects were (41±11) years old, 91.9% (1 609/1 747) were male and 62.2% (1 086/1 747) were daily smokers. The main reasons for smoking included the influence of friends [697 (39.9%)], the need for social entertainment [629 (36.0%)], the relief of mental stress [589 (33.7%)] and the refreshment [459 (26.3%)]. At baseline, 52.9% (885/1 672) and 43.2% (755/1 747) smokers had intention to quit smoking and had planned to quit within one year, respectively. Multivariate logistic regression model analysis showed that: low education level [OR (95%CI) of high school and junior high school and below were 2.42 (1.61, 3.63) and 1.57 (1.18, 2.11)], daily smoking [OR (95%CI): 1.38 (1.06, 1.78)], thinking quitting smoking is not important [OR (95%CI): 4.15 (3.33, 5.18)] and having no quitting experience [OR (95%CI): 3.21 (2.53, 4.05)] were associated with no intention to quit smoking. After intensive smoking cessation intervention, 81.0% (1 415/1 747) smokers started to quit and 36.6% (518/1 415) quit smoking with drugs, both higher than the baseline level (all P values<0.001). By the end of the program, 60.2% (852/1 415) of the medical staff had quit smoking successfully. Conclusion: "Smoking cessation: Doctor first"program can improve the willingness to quit and the proportion of using smoking cessation drugs of medical staff.

Metabolic syndrome-related SNPs in HLA and TNF7L2 may be risk factors for generalized pustular psoriasis in Chinese Han population.

Background: Generalized pustular psoriasis (GPP) is a rare and severe type of psoriasis. Previous studies have reported that metabolic syndrome and its components have been associated with psoriasis. Objective: To investigate the association of metabolic syndrome-related single-nucleotide polymorphisms (SNPs) and GPP in Chinese Han population. Materials and Methods: One hundred and thirty-six (136) GPP patients and 965 healthy controls were recruited in the study. Approximately, 4 ml peripheral venous blood was collected from each participant. After collection, second-generation sequencing was used to detect genetic polymorphism of 15 SNPs. The plink 1.07 software package was used for statistical analysis. Results: Rs805303 (p = 0.01, OR = 0.70) and rs3177928 (p = 3.18E-07, OR = 2.66) in HLA were significantly different between the two groups. Moreover, rs4506565 (p = 1.41E-03, OR = 2.72) and rs7901695 (p = 9.39E-04, OR = 2.82) in TCF7L2 were significantly associated with GPP in patients without a previous history of PsV. Genotype analysis of rs4506565 and rs7901695 showed that under the recessive model, genotype frequencies of rs4506565 (p = 0.00, OR = 18.52) and rs7901695 (p = 0.00, OR = 18.44) were significantly different between GPP patients and healthy controls. Conclusion: Rs805303 and rs3177928 in HLA may increase the risk of GPP in the Chinese Han population. TCF7L2 may be a risk factor for GPP in patients without a previous history of PsV.

SF1670 inhibits apoptosis and inflammation via the PTEN/Akt pathway and thus protects intervertebral disc degeneration.

OBJECTIVE: Intervertebral disc degeneration (IVDD) is associated with the apoptosis of nucleus pulposus (NP) cells. Previous studies have shown that PTEN plays crucial roles in cell survival and apoptosis. The effect of PTEN inhibitors on cell survival following IVDD has been rarely examined. In this study, we investigated the protective effect of SF1670, as a specific PTEN inhibitor, on an in vitro NP cells degenerated model. PATIENTS AND METHODS: We collected human disc samples from IVDD patients and detected PTEN expression in them with different degenerated degrees. NP cells were isolated from the samples and exposed to IL-1ß with or without SF1670. Then, cells viability was determined by CCK-8 assay. We also measured the levels of collagen II, p16, p53, PTEN, Akt, aggrecan, caspase 3/9, Bax, Bcl-2, and several inflammatory factors in NP cells. RESULTS: We found that the expression of PTEN markedly increased in severely degenerated disc tissues. The data showed that IL-1ß upregulated the expressions of p16, p53, PTEN, caspase 3/9, and Bax, but decreased the expressions of collagen II, Akt, aggrecan, and Bcl-2. Surprisingly, the treatment with SF1670 could significantly reverse the regulatory effects of IL-1ß. Moreover, relative levels of IL-6, IL-8, TNF-α, and MMP3/9/13 were significantly suppressed by SF1670 stimuli compared with IL-1ß group. CONCLUSIONS: Overall, these results demonstrated that SF1670 prevented NP degradation via suppressing apoptosis and inflammation through inhibition of PTEN and activation of Akt. SF1670 may become a novel target for the therapy of IVDD in the future.

S-phase kinase-associated protein-2 (Skp2) promotes nucleus pulposus cell proliferation by inhibition of p27 in attenuating intervertebral disc degeneration.

OBJECTIVE: Nucleus pulposus (NP) cell proliferation plays a key role during the process of intervertebral disc degeneration (IDD). S-phase kinase-associated protein-2 (Skp2) has been proved as an important regulator for cell growth factors in vitro. Nonetheless, whether Skp2 attenuates IDD by mediating NP cell proliferation still remains unclear. Therefore, the aim of this study was to explore how Skp2 affected NP cell proliferation and the potential mechanism in vitro. PATIENTS AND METHODS: In this study, we first collected different degenerated human NP samples and isolated NP cells from these tissues. NP cell degenerated model was established with IL-1ß, and the cells were transfected with lentivirus to achieve Skp2 overexpression. Besides, SKPinC1 was used to suppress Skp2 expression in vitro. Western blot, RT-PCR, and immunocytofluorescence were applied to detect genetic differences among groups. Furthermore, cell viability and cell cycle were determined by CCK-8 assay and flow cytometry, respectively. RESULTS: Skp2 expression decreased significantly in degenerated disc samples (p<0.05). IL-1ß stimulation significantly promoted NP cell degeneration, which could be reversed by Skp2 overexpression (p<0.05). Meanwhile, Skp2 in IDD significantly inhibited the expression level of medial p27 and promoted cell cycle by CDK2 activation (p<0.05). In addition, Skp2 suppression affected NP cell proliferation in vitro. CONCLUSIONS: NP cells exhibited significantly inhibited proliferation ability when down-regulated the expression level of Skp2. Our findings provided a more meritorious viewpoint of Skp2 in NP cell proliferation. Furthermore, the above results suggested that Skp2 was a novel target in the treatment of IDD.

[Analysis of sleep quality of a prison police].

Objective: To investigate the sleep quality of prison policemen and explore its influencing factors, so as to provide reference for improving the sleep quality of prison policemen. Methods: In August 2013, 177 policemen in a prison were selected by cluster sampling. The sleep quality of 177 prison policemen was investigated by Pittsburgh Sleep Quality Index Scale and General Situation Questionnaire, and the influencing factors were analyzed. Results: The PSQI scores of 177 prison policemen were (7.47+3.80). There were significant differences between the PSQI scores of prison policemen and the normal adult norm (P<0.05). According to the standard of poor sleep quality, 84 prison policemen (47.46%) had poor sleep quality, and the prison policemen scored higher on daytime dysfunction, subjective sleep quality, sleeping time and sleeping time components. Single factor t test and single factor variance analysis showed that there were significant differences in sleep quality among prison policemen in gender, age, educational level and job classification (P <0.05). The results of multiple stepwise regression analysis showed that gender, age and job classification entered the regression equation with PSQI total score as dependent variable (ß=0.167, 0.270, 0.222) . Conclusion: The sleep quality of prison policemen is worse than that of normal adults, and is affected by gender, age, job classification and other factors, which should be paid attention to by prison administrators.

[Surgical technique and outcomes of uteri retrieval from brain-dead multi-organ donors: a preclinical research of human uterine transplantation].

Objective: To evaluate the surgical technique and outcomes of uteri retrieval from brain-dead multi-organ donors.This study is a preclinical research of human living uterine transplantation. Methods: From May, 2015 to May, 2017, four uteri retrieval procedures, characterized with radical hysterectomy and uterine vascular pedicles dissection, were performed in multi-organ brain-dead donors.The uterus was the third authorized organ after the kidney and liver retrieval procedures in the first two cases.The uterine pedicles included the uterus, ovaries, fallopian tubes, the upper one-third of the vagina and internal iliac vessels or external iliac vessels.The perfusion of the uterus was conducted after the retrieval for evaluating the availability, followed by histopathological examination of the uterine issues per 30 minutes. Results: Since the uterine vein was quite difficult to identify and dissect in the first two case, which result in the rupture of triple uterine veins.Therefore, the uterine venous vessels including uterine vein connected with internal iliac vein and internal iliac arteries were selected as vascular grafts and dissected successfully in the last two cases, which could be perfused with the mixture of 4 ℃ heparinized physiological saline through each artery because of shortening the surgical time and arranging the uterine procurement as the first authorized organ procedure.Mean (SD) operative time was 152.5±39.0 min (115-215 min, n=4). Conclusion: Our preliminary experience indicated that the uterus could be retrieved from the brain-dead multi-organ donors and transplanted to the recipient.The attempt of skeletonizing the uterine veins should be replaced by dissection of internal iliac vein.

[A survey of sleep quality of employed nurses in military hospitals].

Objective: To investigate the sleep quality of the employed nurses in three grade A tertiary military hospitals in Beijing, China and its influential factors and to provide a reference for improving the sleep quality of employed nurses. Methods: From January 2014 to January 2017, a questionnaire survey was carried out to investigate the sleep quality of 253 employed nurses in three grade A tertiary military hospitals in Beijing, China using the Pittsburgh Sleep Quality Index (PSQI) and a general status questionnaire. The results were compared with the adult norms to analyze the influential factors for sleep quality of the employed nurses. Results: The global PSQI score of the 253 employed nurses was 7.76 ± 3.53. Their global PSQI score and PSQI component scores were significantly higher than the adults norms (P<0.05) . And 54.94% of the employed nurses had poor sleep quality; they had high scores of daytime dysfunction (1.39±0.83) , sleep latency (1.67±0.94) , sleep quality (1.33±0.88) , and sleep time (1.23±0.78) . The one-way analysis of variance showed that the sleep quality of the employed nurses was associated with nursing age, educational background, professional title, whether to have children, frequency of night shifts, and department (P<0.05) . The multivariate logistic regression analysis showed that the risk factors for sleep quality of the employed nurses were technical secondary school education (OR=4.292) and emergency department and intensive care unit (OR=2.582) ; the protective factors for sleep quality of the employed nurses were outpatient department and assistant department (OR=0.312) , no children (OR=0.318) , and no night shift (OR=0.332) . Conclusion: The employed nurses in military hospitals have poorer sleep quality than the normal adults. The influential factors for sleep quality of employed nurses are educational background, department, whether to have children, and frequency of night shifts.

MicroRNA-122 regulates caspase-8 and promotes the apoptosis of mouse cardiomyocytes.

Cardiomyocyte apoptosis plays key roles in the pathogenesis of heart diseases such as myocardial infarction. MicroRNAs are important regulators of gene expression, which are also involved in the regulation of cardiomyocyte apoptosis. However, cardiomyocyte apoptosis regulated by microRNA (miR)-122 is largely unexplored. The aim of this study focused on the role of miR-122 in cardiomyocyte apoptosis. Cardiomyocytes were isolated from neonatal mice and primarily cultured. MiR-122 mimic and inhibitor were transfected to cardiomyocytes and verified by qRT-PCR. Cell viability and apoptosis post-transfection were assessed by MTT assay and flow cytometry, respectively. Changes in expression of caspase-8 were quantified by qRT-PCR and western blot. Results showed that miR-122 mimic and inhibitor successfully induced changes in miR-122 levels in cultured cardiomyocytes (P<0.01). MiR-122 overexpression suppressed viability and promoted apoptosis of cardiomyocytes (P<0.05), and miR-122 knockdown promoted cell viability and inhibited apoptosis (P<0.05). The mRNA and protein levels of caspase-8 were elevated by miR-122 overexpression (P<0.01) and reduced by miR-122 knockdown (P<0.001). These results suggest an inductive role of miR-122 in cardiomyocyte apoptosis, which may be related to its regulation on caspase-8.

[The effect of monrustet on the exhalation of nitric oxide and inflammatory cytokines in patients with asthma combined with OSAHS].

Objective:To study the effect of monrustet on fractional exhaled nitric oxide and inflammatory cytokines in the elderly with bronchial asthma combined obstructive sleep apnea hypopnea syndrome.Method:150 cases diagnosed as asthma were enrolled in this study. The patients were divided into bronchial asthma combined with OSAHS (n=72)and bronchial asthma (n=78). According to the different treatment methods , patients were divided into observation group and control group. Two groups were given common treatment with inhaled corticosteroids, and the observation group was taken orally montrast 10mg/night additionally. The fractional exhaled nitric oxide was detected before and after treatment. Serum were collected for detection of tumor necrosis factor alpha (TNR-α), Creactive protein (CRP) and interleukin 6 (IL-6), according to the sleep monitoring results, the sleep apnea low ventilation index (AHI) was calculated, and the changes of FeNO level,CRP,TNR-α,IL-6 and AHI were analyzed in the two groups.Result:Before treatment, the gender, age, degree of disease, FeNO level,TNR-α, CRP,IL-6 and AHI differences were not statistically significant in the two groups (P>0.05).After treatment, both groups of FeNO, TNR-α,CRP,IL-6 and AHI decreased before treatment (P < 0.05).The observation group was lower than the control group, and the difference was statistically significant (FeNO level, AHIP< 0.01,TNR-α, CRP,IL-6 P< 0.05).Conclusion::Montelukast can reduce the FeNO level, the expression of TNR-α, CRP, and IL-6 of patients of bronchial asthma combined with OSAHS. Further improvement of the patient's condition, and provide reference value for the clinical medicine of patients with asthma.

[Role of sleep apnea monitoring management platform in the treatment of patients with obstructive sleep apnea hypopnea syndrome].

Objective:To investigate the clinical significance and value of the sleep apnea monitoring management platform in the treatment of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) by comparing with the traditional continuous positive airway pressure (CPAP) card reader mode.Method:A total of 48 severe adult OSAHS patients from Department of Otorhinolaryngology Head and Neck Surgery-Sleep Medical Center of the Third People's Hospital of Honghe during the period of Nov. 2015 to Aug. 2016 were collected in this prospective study. All of them were diagnosed by PSG and treated with nasal continuous positive airway pressure. They were randomly divided into group A (n=24) and group B (n=24). Group A and B were treated with the traditional CPAP card reader mode and the sleep apnea monitoring management platform respectively. During the follow-up, the compliance, mean blood oxygen saturation, titration pressure, Epworth sleepiness scale after 1, 3, 6 and 12 month treatment were compared between two groups. Ttest was used to analyze the difference. Statistical significance was set at P <0.05.Result:Statistical analysis showed that there were significant difference in the compliance of using CPAP, mean blood oxygen saturation and Epworth sleepiness scale score between the two groups (P < 0.05), but the titration pressure had no difference between the two groups (P>0.05).Conclusion:Compared the sleep apnea monitoring management platform with traditional CPAP card reader mode in the treatment of OSAHS patients, the former could solve the problems during the CPAP use in time, improve the compliance of using CPAP, and which could increase the efficacy of CPAP. Thus, the sleep apnea monitoring management platform is of more clinical value and deserve promotion.

[Effects of ketotifen on fractional exhaled nitric oxide in patients with combined allergic rhinitis and asthma syndrome].

Objective:To study effects of ketotifen on fractional exhaled nitric oxide in patients with combined allergic rhinitis and asthma syndrome.Method:One hundred and twelve patients with asthma were selected from department of respiration, Affiliated Hospital of North China University of science and technology from January 2016 to 2017 in March. Eighty-four patients with allergic rhinitis were selected as the subjects, Randomly divided into two groups,including observed group(n=42) and control group(n=42).The control group was treated with antitussive,expectorant and inhaled corticosteroids, while the observed group in the control group combined with ketotifen 1 mg 2/ day oral treatment,the changes of FeNO and IL-17 in the two groups were compared after one month treament.Result:Before treatment, two groups of patients in general IL-17 and fractional exhaled nitric oxide ware no significant difference(P> 0.05).After treatment, compared to the control group, the observed group was significantly more effective,the difference was statistically significant(P <0.05);fractional exhaled nitric oxide in treatment group were lower than those in control group, the difference was statistically significant(P<0.05,P< 0.01).And the observed group was lower than the control group, and the differences were statistically significant,t(P<0.05).Conclusion:Ketotifen significantly reduce the FeNO of allergic rhinitis and asthma syndrome, reduce airway inflammation.

[Relationship between personality characteristics and turnover intention of medical staff in an infectious disease hospital].

Objective: To investigate the relationship between personality characteristics and turnover intention of the medical staff in an infectious diseases hospital. Methods: Using the cluster sampling method, a total of 366 members of medical staff were selected from different departments in an infectious disease hospital from May to August, 2013. The general information, such as sex, age, education level, and professional title, were collected and they were subjected to a survey using Cattell's 16 Personality Factor Questionnaire and Turnover Intention Scale. The data were subjected to logistic regression analysis. Results: Compared with the Chinese norm, the medical staff in the infectious disease hospital had significantly higher scores of intelligence, stability, bullying, excitability, perseverance, social boldness, fantasy, privateness, independence, and self-discipline and significantly lower scores of gregariousness, sensitivity, suspicion, anxiety, and tension (P<0.05). Of the 366 members of medical staff, 22 (6.01%) had a very low turnover intention, low in 152 (41.53%) , high in 61 (16.67%) , and very high in 131 (35.79%). The logistic regression analysis showed that sensitivity, suspicion, fantasy, privateness, anxiety, openness to change, and independence were the risk factors for turnover intention (P<0.05) . Conclusion: Compared with the Chinese norm, the medical staff in the infectious disease hospital have a better mental quality and a higher turnover intention. The individuals with sensitivity, suspicion, fantasy, and anxiety are prone to having turnover intention.

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.

Inversion of infrared imaging bolometer based on one-dimensional and three-dimensional modeling in HL-2A.

Linear regularization has been applied to the HL-2A infrared imaging bolometer to reconstruct local plasma emission with one-dimensional (1D) and three-dimensional (3D) modeling under the assumption of toroidal symmetry. In the 3D modeling, a new method to calculate the detector point response function is introduced. This method can be adapted to an arbitrarily shaped pinhole. With the full 3D treatment of the detector geometry, up to 50% of the mean-squared error is reduced compared with the 1D modeling. This is attributed to the effects of finite detector size being taken into account in the 3D modeling. Meanwhile, the number of the bolometer pixels has been optimized to 20 × 20 by making a trade-off between the number of bolometer pixels and the sensitivity of the system. The plasma radiated power density distributions have been calculated as a demonstration using 1D modeling and 3D modeling, respectively.

Development of frequency modulated continuous wave reflectometer for electron density profile measurement on the HL-2A tokamak.

The frequency modulated continuous wave reflectometer was developed for the first time on the HL-2A tokamak. The system utilizes a voltage controlled oscillator and an active multiplier for broadband coverage and detects as heterodyne mode. Three reflectometers have been installed and operated in extraordinary mode polarization on HL-2A to measure density profiles at low field side, covering the Q-band (33-50 GHz), V-band (50-75 GHz), and W-band (75-110 GHz). For density profile reconstruction from the phase shift of the probing wave, a corrected phase unwrapping method is introduced in this article. The effectiveness of the method is demonstrated. The density profile behavior of a fast plasma event is presented and it demonstrates the capability of the reflectometer. These diagnostics will be contributed to the routine density profile measurements and the plasma physics study on HL-2A.

Development of electron cyclotron emission imaging system on the HL-2A tokamak.

A 2D electron cyclotron emission imaging (ECEI) system has been developed for measurement of electron temperature fluctuations in the HL-2A tokamak. It is comprised of a front-end 24 channel heterodyne imaging array with a tunable RF range spanning 75-110 GHz, and a set of back-end ECEI electronics that together generate 24 × 8 = 192 channel images of the 2nd harmonic X-mode electron cyclotron emission from the HL-2A plasma. The simulated performance of the local oscillator (LO) optics and radio frequency (RF) optics is presented, together with the laboratory characterization results. The Gaussian beams from the LO optics are observed to properly cover the entire detector array. The ECE signals from the plasma are mixed with the LO signal in the array box, then delivered to the electronics system by low-loss microwave cables, and finally to the digitizers. The ECEI system can achieve temporal resolutions of ~µs, and spatial resolutions of 1 cm (radially) and 2 cm (poloidally).

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.

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.